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llvm-project/llvm/tools/dsymutil/DwarfLinker.cpp
James Henderson a3acf99e59 [DWARF] Rework debug line parsing to use llvm::Error and callbacks 
Reviewed by: dblaikie, JDevlieghere, espindola

Differential Revision: https://reviews.llvm.org/D44560

Summary:
The .debug_line parser previously reported errors by printing to stderr and
return false. This is not particularly helpful for clients of the library code,
as it prevents them from handling the errors in a manner based on the calling
context. This change switches to using llvm::Error and callbacks to indicate
what problems were detected during parsing, and has updated clients to handle
the errors in a location-specific manner. In general, this means that they
continue to do the same thing to external users. Below, I have outlined what
the known behaviour changes are, relating to this change.

There are two levels of "errors" in the new error mechanism, to broadly
distinguish between different fail states of the parser, since not every
failure will prevent parsing of the unit, or of subsequent unit. Malformed
table errors that prevent reading the remainder of the table (reported by
returning them) and other minor issues representing problems with parsing that
do not prevent attempting to continue reading the table (reported by calling a
specified callback funciton). The only example of this currently is when the
last sequence of a unit is unterminated. However, I think it would be good to
change the handling of unrecognised opcodes to report as minor issues as well,
rather than just printing to the stream if --verbose is used (this would be a
subsequent change however).

I have substantially extended the DwarfGenerator to be able to handle
custom-crafted .debug_line sections, allowing for comprehensive unit-testing
of the parser code. For now, I am just adding unit tests to cover the basic
error reporting, and positive cases, and do not currently intend to test every
part of the parser, although the framework should be sufficient to do so at a
later point.

Known behaviour changes:
  - The dump function in DWARFContext now does not attempt to read subsequent
  tables when searching for a specific offset, if the unit length field of a
  table before the specified offset is a reserved value.
  - getOrParseLineTable now returns a useful Error if an invalid offset is
  encountered, rather than simply a nullptr.
  - The parse functions no longer use `WithColor::warning` directly to report
  errors, allowing LLD to call its own warning function.
  - The existing parse error messages have been updated to not specifically
  include "warning" in their message, allowing consumers to determine what
  severity the problem is.
  - If the line table version field appears to have a value less than 2, an
  informative error is returned, instead of just false.
  - If the line table unit length field uses a reserved value, an informative
  error is returned, instead of just false.
  - Dumping of .debug_line.dwo sections is now implemented the same as regular
  .debug_line sections.
  - Verbose dumping of .debug_line[.dwo] sections now prints the prologue, if
  there is a prologue error, just like non-verbose dumping.

As a helper for the generator code, I have re-added emitInt64 to the
AsmPrinter code. This previously existed, but was removed way back in r100296,
presumably because it was dead at the time.

This change also requires a change to LLD, which will be committed separately.

llvm-svn: 331971
2018-05-10 10:51:33 +00:00

4447 lines
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//===- tools/dsymutil/DwarfLinker.cpp - Dwarf debug info linker -----------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "BinaryHolder.h"
#include "DebugMap.h"
#include "MachOUtils.h"
#include "NonRelocatableStringpool.h"
#include "dsymutil.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/Hashing.h"
#include "llvm/ADT/IntervalMap.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/PointerIntPair.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Triple.h"
#include "llvm/ADT/Twine.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/BinaryFormat/MachO.h"
#include "llvm/CodeGen/AccelTable.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/DIE.h"
#include "llvm/Config/config.h"
#include "llvm/DebugInfo/DIContext.h"
#include "llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h"
#include "llvm/DebugInfo/DWARF/DWARFContext.h"
#include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
#include "llvm/DebugInfo/DWARF/DWARFDie.h"
#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
#include "llvm/DebugInfo/DWARF/DWARFSection.h"
#include "llvm/DebugInfo/DWARF/DWARFUnit.h"
#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDwarf.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCTargetOptions.h"
#include "llvm/MC/MCTargetOptionsCommandFlags.inc"
#include "llvm/Object/MachO.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Object/SymbolicFile.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/DJB.h"
#include "llvm/Support/DataExtractor.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/LEB128.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/ThreadPool.h"
#include "llvm/Support/ToolOutputFile.h"
#include "llvm/Support/WithColor.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include <algorithm>
#include <cassert>
#include <cinttypes>
#include <climits>
#include <cstdint>
#include <cstdlib>
#include <cstring>
#include <limits>
#include <map>
#include <memory>
#include <string>
#include <system_error>
#include <tuple>
#include <utility>
#include <vector>
namespace llvm {
namespace dsymutil {
namespace {
/// Helper for making strong types.
template <typename T, typename S> class StrongType : public T {
public:
template <typename... Args>
explicit StrongType(Args... A) : T(std::forward<Args>(A)...) {}
};
/// It's very easy to introduce bugs by passing the wrong string pool. By using
/// strong types the interface enforces that the right kind of pool is used.
struct UniqueTag {};
struct OffsetsTag {};
using UniquingStringPool = StrongType<NonRelocatableStringpool, UniqueTag>;
using OffsetsStringPool = StrongType<NonRelocatableStringpool, OffsetsTag>;
/// Small helper that resolves and caches file paths. This helps reduce the
/// number of calls to realpath which is expensive. We assume the input are
/// files, and cache the realpath of their parent. This way we can quickly
/// resolve different files under the same path.
class CachedPathResolver {
public:
/// Resolve a path by calling realpath and cache its result. The returned
/// StringRef is interned in the given \p StringPool.
StringRef resolve(std::string Path, NonRelocatableStringpool &StringPool) {
StringRef FileName = sys::path::filename(Path);
SmallString<256> ParentPath = sys::path::parent_path(Path);
// If the ParentPath has not yet been resolved, resolve and cache it for
// future look-ups.
if (!ResolvedPaths.count(ParentPath)) {
SmallString<256> RealPath;
sys::fs::real_path(ParentPath, RealPath);
ResolvedPaths.insert({ParentPath, StringRef(RealPath).str()});
}
// Join the file name again with the resolved path.
SmallString<256> ResolvedPath(ResolvedPaths[ParentPath]);
sys::path::append(ResolvedPath, FileName);
return StringPool.internString(ResolvedPath);
}
private:
StringMap<std::string> ResolvedPaths;
};
/// Retrieve the section named \a SecName in \a Obj.
///
/// To accommodate for platform discrepancies, the name passed should be
/// (for example) 'debug_info' to match either '__debug_info' or '.debug_info'.
/// This function will strip the initial platform-specific characters.
static Optional<object::SectionRef>
getSectionByName(const object::ObjectFile &Obj, StringRef SecName) {
for (const object::SectionRef &Section : Obj.sections()) {
StringRef SectionName;
Section.getName(SectionName);
SectionName = SectionName.substr(SectionName.find_first_not_of("._"));
if (SectionName != SecName)
continue;
return Section;
}
return None;
}
template <typename KeyT, typename ValT>
using HalfOpenIntervalMap =
IntervalMap<KeyT, ValT, IntervalMapImpl::NodeSizer<KeyT, ValT>::LeafSize,
IntervalMapHalfOpenInfo<KeyT>>;
using FunctionIntervals = HalfOpenIntervalMap<uint64_t, int64_t>;
// FIXME: Delete this structure.
struct PatchLocation {
DIE::value_iterator I;
PatchLocation() = default;
PatchLocation(DIE::value_iterator I) : I(I) {}
void set(uint64_t New) const {
assert(I);
const auto &Old = *I;
assert(Old.getType() == DIEValue::isInteger);
*I = DIEValue(Old.getAttribute(), Old.getForm(), DIEInteger(New));
}
uint64_t get() const {
assert(I);
return I->getDIEInteger().getValue();
}
};
class CompileUnit;
struct DeclMapInfo;
/// A DeclContext is a named program scope that is used for ODR
/// uniquing of types.
/// The set of DeclContext for the ODR-subject parts of a Dwarf link
/// is expanded (and uniqued) with each new object file processed. We
/// need to determine the context of each DIE in an linked object file
/// to see if the corresponding type has already been emitted.
///
/// The contexts are conceptually organized as a tree (eg. a function
/// scope is contained in a namespace scope that contains other
/// scopes), but storing/accessing them in an actual tree is too
/// inefficient: we need to be able to very quickly query a context
/// for a given child context by name. Storing a StringMap in each
/// DeclContext would be too space inefficient.
/// The solution here is to give each DeclContext a link to its parent
/// (this allows to walk up the tree), but to query the existence of a
/// specific DeclContext using a separate DenseMap keyed on the hash
/// of the fully qualified name of the context.
class DeclContext {
friend DeclMapInfo;
unsigned QualifiedNameHash = 0;
uint32_t Line = 0;
uint32_t ByteSize = 0;
uint16_t Tag = dwarf::DW_TAG_compile_unit;
unsigned DefinedInClangModule : 1;
StringRef Name;
StringRef File;
const DeclContext &Parent;
DWARFDie LastSeenDIE;
uint32_t LastSeenCompileUnitID = 0;
uint32_t CanonicalDIEOffset = 0;
public:
using Map = DenseSet<DeclContext *, DeclMapInfo>;
DeclContext() : DefinedInClangModule(0), Parent(*this) {}
DeclContext(unsigned Hash, uint32_t Line, uint32_t ByteSize, uint16_t Tag,
StringRef Name, StringRef File, const DeclContext &Parent,
DWARFDie LastSeenDIE = DWARFDie(), unsigned CUId = 0)
: QualifiedNameHash(Hash), Line(Line), ByteSize(ByteSize), Tag(Tag),
DefinedInClangModule(0), Name(Name), File(File), Parent(Parent),
LastSeenDIE(LastSeenDIE), LastSeenCompileUnitID(CUId) {}
uint32_t getQualifiedNameHash() const { return QualifiedNameHash; }
bool setLastSeenDIE(CompileUnit &U, const DWARFDie &Die);
uint32_t getCanonicalDIEOffset() const { return CanonicalDIEOffset; }
void setCanonicalDIEOffset(uint32_t Offset) { CanonicalDIEOffset = Offset; }
bool isDefinedInClangModule() const { return DefinedInClangModule; }
void setDefinedInClangModule(bool Val) { DefinedInClangModule = Val; }
uint16_t getTag() const { return Tag; }
StringRef getName() const { return Name; }
};
/// Info type for the DenseMap storing the DeclContext pointers.
struct DeclMapInfo : private DenseMapInfo<DeclContext *> {
using DenseMapInfo<DeclContext *>::getEmptyKey;
using DenseMapInfo<DeclContext *>::getTombstoneKey;
static unsigned getHashValue(const DeclContext *Ctxt) {
return Ctxt->QualifiedNameHash;
}
static bool isEqual(const DeclContext *LHS, const DeclContext *RHS) {
if (RHS == getEmptyKey() || RHS == getTombstoneKey())
return RHS == LHS;
return LHS->QualifiedNameHash == RHS->QualifiedNameHash &&
LHS->Line == RHS->Line && LHS->ByteSize == RHS->ByteSize &&
LHS->Name.data() == RHS->Name.data() &&
LHS->File.data() == RHS->File.data() &&
LHS->Parent.QualifiedNameHash == RHS->Parent.QualifiedNameHash;
}
};
/// This class gives a tree-like API to the DenseMap that stores the
/// DeclContext objects. It also holds the BumpPtrAllocator where
/// these objects will be allocated.
class DeclContextTree {
BumpPtrAllocator Allocator;
DeclContext Root;
DeclContext::Map Contexts;
/// Cache resolved paths from the line table.
CachedPathResolver PathResolver;
public:
/// Get the child of \a Context described by \a DIE in \a Unit. The
/// required strings will be interned in \a StringPool.
/// \returns The child DeclContext along with one bit that is set if
/// this context is invalid.
///
/// An invalid context means it shouldn't be considered for uniquing, but its
/// not returning null, because some children of that context might be
/// uniquing candidates.
///
/// FIXME: The invalid bit along the return value is to emulate some
/// dsymutil-classic functionality.
PointerIntPair<DeclContext *, 1>
getChildDeclContext(DeclContext &Context, const DWARFDie &DIE,
CompileUnit &Unit, UniquingStringPool &StringPool,
bool InClangModule);
DeclContext &getRoot() { return Root; }
};
/// Stores all information relating to a compile unit, be it in its original
/// instance in the object file to its brand new cloned and linked DIE tree.
class CompileUnit {
public:
/// Information gathered about a DIE in the object file.
struct DIEInfo {
/// Address offset to apply to the described entity.
int64_t AddrAdjust;
/// ODR Declaration context.
DeclContext *Ctxt;
/// Cloned version of that DIE.
DIE *Clone;
/// The index of this DIE's parent.
uint32_t ParentIdx;
/// Is the DIE part of the linked output?
bool Keep : 1;
/// Was this DIE's entity found in the map?
bool InDebugMap : 1;
/// Is this a pure forward declaration we can strip?
bool Prune : 1;
/// Does DIE transitively refer an incomplete decl?
bool Incomplete : 1;
};
CompileUnit(DWARFUnit &OrigUnit, unsigned ID, bool CanUseODR,
StringRef ClangModuleName)
: OrigUnit(OrigUnit), ID(ID), Ranges(RangeAlloc),
ClangModuleName(ClangModuleName) {
Info.resize(OrigUnit.getNumDIEs());
auto CUDie = OrigUnit.getUnitDIE(false);
if (!CUDie) {
HasODR = false;
return;
}
if (auto Lang = dwarf::toUnsigned(CUDie.find(dwarf::DW_AT_language)))
HasODR = CanUseODR && (*Lang == dwarf::DW_LANG_C_plus_plus ||
*Lang == dwarf::DW_LANG_C_plus_plus_03 ||
*Lang == dwarf::DW_LANG_C_plus_plus_11 ||
*Lang == dwarf::DW_LANG_C_plus_plus_14 ||
*Lang == dwarf::DW_LANG_ObjC_plus_plus);
else
HasODR = false;
}
DWARFUnit &getOrigUnit() const { return OrigUnit; }
unsigned getUniqueID() const { return ID; }
void createOutputDIE() {
NewUnit.emplace(OrigUnit.getVersion(), OrigUnit.getAddressByteSize(),
OrigUnit.getUnitDIE().getTag());
}
DIE *getOutputUnitDIE() const {
if (NewUnit)
return &const_cast<BasicDIEUnit &>(*NewUnit).getUnitDie();
return nullptr;
}
bool hasODR() const { return HasODR; }
bool isClangModule() const { return !ClangModuleName.empty(); }
const std::string &getClangModuleName() const { return ClangModuleName; }
DIEInfo &getInfo(unsigned Idx) { return Info[Idx]; }
const DIEInfo &getInfo(unsigned Idx) const { return Info[Idx]; }
uint64_t getStartOffset() const { return StartOffset; }
uint64_t getNextUnitOffset() const { return NextUnitOffset; }
void setStartOffset(uint64_t DebugInfoSize) { StartOffset = DebugInfoSize; }
uint64_t getLowPc() const { return LowPc; }
uint64_t getHighPc() const { return HighPc; }
bool hasLabelAt(uint64_t Addr) const { return Labels.count(Addr); }
Optional<PatchLocation> getUnitRangesAttribute() const {
return UnitRangeAttribute;
}
const FunctionIntervals &getFunctionRanges() const { return Ranges; }
const std::vector<PatchLocation> &getRangesAttributes() const {
return RangeAttributes;
}
const std::vector<std::pair<PatchLocation, int64_t>> &
getLocationAttributes() const {
return LocationAttributes;
}
void setHasInterestingContent() { HasInterestingContent = true; }
bool hasInterestingContent() { return HasInterestingContent; }
/// Mark every DIE in this unit as kept. This function also
/// marks variables as InDebugMap so that they appear in the
/// reconstructed accelerator tables.
void markEverythingAsKept();
/// Compute the end offset for this unit. Must be called after the CU's DIEs
/// have been cloned. \returns the next unit offset (which is also the
/// current debug_info section size).
uint64_t computeNextUnitOffset();
/// Keep track of a forward reference to DIE \p Die in \p RefUnit by \p
/// Attr. The attribute should be fixed up later to point to the absolute
/// offset of \p Die in the debug_info section or to the canonical offset of
/// \p Ctxt if it is non-null.
void noteForwardReference(DIE *Die, const CompileUnit *RefUnit,
DeclContext *Ctxt, PatchLocation Attr);
/// Apply all fixups recorded by noteForwardReference().
void fixupForwardReferences();
/// Add the low_pc of a label that is relocated by applying
/// offset \p PCOffset.
void addLabelLowPc(uint64_t LabelLowPc, int64_t PcOffset);
/// Add a function range [\p LowPC, \p HighPC) that is relocated by applying
/// offset \p PCOffset.
void addFunctionRange(uint64_t LowPC, uint64_t HighPC, int64_t PCOffset);
/// Keep track of a DW_AT_range attribute that we will need to patch up later.
void noteRangeAttribute(const DIE &Die, PatchLocation Attr);
/// Keep track of a location attribute pointing to a location list in the
/// debug_loc section.
void noteLocationAttribute(PatchLocation Attr, int64_t PcOffset);
/// Add a name accelerator entry for \a Die with \a Name.
void addNamespaceAccelerator(const DIE *Die, DwarfStringPoolEntryRef Name);
/// Add a name accelerator entry for \a Die with \a Name.
void addNameAccelerator(const DIE *Die, DwarfStringPoolEntryRef Name,
bool SkipPubnamesSection = false);
/// Add various accelerator entries for \p Die with \p Name which is stored
/// in the string table at \p Offset. \p Name must be an Objective-C
/// selector.
void addObjCAccelerator(const DIE *Die, DwarfStringPoolEntryRef Name,
bool SkipPubnamesSection = false);
/// Add a type accelerator entry for \p Die with \p Name which is stored in
/// the string table at \p Offset.
void addTypeAccelerator(const DIE *Die, DwarfStringPoolEntryRef Name,
bool ObjcClassImplementation,
uint32_t QualifiedNameHash);
struct AccelInfo {
/// Name of the entry.
DwarfStringPoolEntryRef Name;
/// DIE this entry describes.
const DIE *Die;
/// Hash of the fully qualified name.
uint32_t QualifiedNameHash;
/// Emit this entry only in the apple_* sections.
bool SkipPubSection;
/// Is this an ObjC class implementation?
bool ObjcClassImplementation;
AccelInfo(DwarfStringPoolEntryRef Name, const DIE *Die,
bool SkipPubSection = false)
: Name(Name), Die(Die), SkipPubSection(SkipPubSection) {}
AccelInfo(DwarfStringPoolEntryRef Name, const DIE *Die,
uint32_t QualifiedNameHash, bool ObjCClassIsImplementation)
: Name(Name), Die(Die), QualifiedNameHash(QualifiedNameHash),
SkipPubSection(false),
ObjcClassImplementation(ObjCClassIsImplementation) {}
};
const std::vector<AccelInfo> &getPubnames() const { return Pubnames; }
const std::vector<AccelInfo> &getPubtypes() const { return Pubtypes; }
const std::vector<AccelInfo> &getNamespaces() const { return Namespaces; }
const std::vector<AccelInfo> &getObjC() const { return ObjC; }
/// Get the full path for file \a FileNum in the line table
StringRef getResolvedPath(unsigned FileNum) {
if (FileNum >= ResolvedPaths.size())
return StringRef();
return ResolvedPaths[FileNum];
}
/// Set the fully resolved path for the line-table's file \a FileNum
/// to \a Path.
void setResolvedPath(unsigned FileNum, StringRef Path) {
if (ResolvedPaths.size() <= FileNum)
ResolvedPaths.resize(FileNum + 1);
ResolvedPaths[FileNum] = Path;
}
private:
DWARFUnit &OrigUnit;
unsigned ID;
std::vector<DIEInfo> Info; ///< DIE info indexed by DIE index.
Optional<BasicDIEUnit> NewUnit;
uint64_t StartOffset;
uint64_t NextUnitOffset;
uint64_t LowPc = std::numeric_limits<uint64_t>::max();
uint64_t HighPc = 0;
/// A list of attributes to fixup with the absolute offset of
/// a DIE in the debug_info section.
///
/// The offsets for the attributes in this array couldn't be set while
/// cloning because for cross-cu forward references the target DIE's offset
/// isn't known you emit the reference attribute.
std::vector<
std::tuple<DIE *, const CompileUnit *, DeclContext *, PatchLocation>>
ForwardDIEReferences;
FunctionIntervals::Allocator RangeAlloc;
/// The ranges in that interval map are the PC ranges for
/// functions in this unit, associated with the PC offset to apply
/// to the addresses to get the linked address.
FunctionIntervals Ranges;
/// The DW_AT_low_pc of each DW_TAG_label.
SmallDenseMap<uint64_t, uint64_t, 1> Labels;
/// DW_AT_ranges attributes to patch after we have gathered
/// all the unit's function addresses.
/// @{
std::vector<PatchLocation> RangeAttributes;
Optional<PatchLocation> UnitRangeAttribute;
/// @}
/// Location attributes that need to be transferred from the
/// original debug_loc section to the liked one. They are stored
/// along with the PC offset that is to be applied to their
/// function's address.
std::vector<std::pair<PatchLocation, int64_t>> LocationAttributes;
/// Accelerator entries for the unit, both for the pub*
/// sections and the apple* ones.
/// @{
std::vector<AccelInfo> Pubnames;
std::vector<AccelInfo> Pubtypes;
std::vector<AccelInfo> Namespaces;
std::vector<AccelInfo> ObjC;
/// @}
/// Cached resolved paths from the line table.
/// Note, the StringRefs here point in to the intern (uniquing) string pool.
/// This means that a StringRef returned here doesn't need to then be uniqued
/// for the purposes of getting a unique address for each string.
std::vector<StringRef> ResolvedPaths;
/// Is this unit subject to the ODR rule?
bool HasODR;
/// Did a DIE actually contain a valid reloc?
bool HasInterestingContent;
/// If this is a Clang module, this holds the module's name.
std::string ClangModuleName;
};
/// Check if the DIE at \p Idx is in the scope of a function.
static bool inFunctionScope(CompileUnit &U, unsigned Idx) {
while (Idx) {
if (U.getOrigUnit().getDIEAtIndex(Idx).getTag() == dwarf::DW_TAG_subprogram)
return true;
Idx = U.getInfo(Idx).ParentIdx;
}
return false;
}
} // namespace
void warn(Twine Warning, Twine Context) {
WithColor::warning() << Warning + "\n";
if (!Context.isTriviallyEmpty())
WithColor::note() << Twine("while processing ") + Context + "\n";
}
bool error(Twine Error, Twine Context) {
WithColor::error() << Error + "\n";
if (!Context.isTriviallyEmpty())
WithColor::note() << Twine("while processing ") + Context + "\n";
return false;
}
void CompileUnit::markEverythingAsKept() {
unsigned Idx = 0;
setHasInterestingContent();
for (auto &I : Info) {
// Mark everything that wasn't explicit marked for pruning.
I.Keep = !I.Prune;
auto DIE = OrigUnit.getDIEAtIndex(Idx++);
// Try to guess which DIEs must go to the accelerator tables. We do that
// just for variables, because functions will be handled depending on
// whether they carry a DW_AT_low_pc attribute or not.
if (DIE.getTag() != dwarf::DW_TAG_variable &&
DIE.getTag() != dwarf::DW_TAG_constant)
continue;
Optional<DWARFFormValue> Value;
if (!(Value = DIE.find(dwarf::DW_AT_location))) {
if ((Value = DIE.find(dwarf::DW_AT_const_value)) &&
!inFunctionScope(*this, I.ParentIdx))
I.InDebugMap = true;
continue;
}
if (auto Block = Value->getAsBlock()) {
if (Block->size() > OrigUnit.getAddressByteSize() &&
(*Block)[0] == dwarf::DW_OP_addr)
I.InDebugMap = true;
}
}
}
uint64_t CompileUnit::computeNextUnitOffset() {
NextUnitOffset = StartOffset + 11 /* Header size */;
// The root DIE might be null, meaning that the Unit had nothing to
// contribute to the linked output. In that case, we will emit the
// unit header without any actual DIE.
if (NewUnit)
NextUnitOffset += NewUnit->getUnitDie().getSize();
return NextUnitOffset;
}
/// Keep track of a forward cross-cu reference from this unit
/// to \p Die that lives in \p RefUnit.
void CompileUnit::noteForwardReference(DIE *Die, const CompileUnit *RefUnit,
DeclContext *Ctxt, PatchLocation Attr) {
ForwardDIEReferences.emplace_back(Die, RefUnit, Ctxt, Attr);
}
void CompileUnit::fixupForwardReferences() {
for (const auto &Ref : ForwardDIEReferences) {
DIE *RefDie;
const CompileUnit *RefUnit;
PatchLocation Attr;
DeclContext *Ctxt;
std::tie(RefDie, RefUnit, Ctxt, Attr) = Ref;
if (Ctxt && Ctxt->getCanonicalDIEOffset())
Attr.set(Ctxt->getCanonicalDIEOffset());
else
Attr.set(RefDie->getOffset() + RefUnit->getStartOffset());
}
}
void CompileUnit::addLabelLowPc(uint64_t LabelLowPc, int64_t PcOffset) {
Labels.insert({LabelLowPc, PcOffset});
}
void CompileUnit::addFunctionRange(uint64_t FuncLowPc, uint64_t FuncHighPc,
int64_t PcOffset) {
Ranges.insert(FuncLowPc, FuncHighPc, PcOffset);
this->LowPc = std::min(LowPc, FuncLowPc + PcOffset);
this->HighPc = std::max(HighPc, FuncHighPc + PcOffset);
}
void CompileUnit::noteRangeAttribute(const DIE &Die, PatchLocation Attr) {
if (Die.getTag() != dwarf::DW_TAG_compile_unit)
RangeAttributes.push_back(Attr);
else
UnitRangeAttribute = Attr;
}
void CompileUnit::noteLocationAttribute(PatchLocation Attr, int64_t PcOffset) {
LocationAttributes.emplace_back(Attr, PcOffset);
}
void CompileUnit::addNamespaceAccelerator(const DIE *Die,
DwarfStringPoolEntryRef Name) {
Namespaces.emplace_back(Name, Die);
}
void CompileUnit::addObjCAccelerator(const DIE *Die,
DwarfStringPoolEntryRef Name,
bool SkipPubSection) {
ObjC.emplace_back(Name, Die, SkipPubSection);
}
void CompileUnit::addNameAccelerator(const DIE *Die,
DwarfStringPoolEntryRef Name,
bool SkipPubSection) {
Pubnames.emplace_back(Name, Die, SkipPubSection);
}
void CompileUnit::addTypeAccelerator(const DIE *Die,
DwarfStringPoolEntryRef Name,
bool ObjcClassImplementation,
uint32_t QualifiedNameHash) {
Pubtypes.emplace_back(Name, Die, QualifiedNameHash, ObjcClassImplementation);
}
namespace {
/// The Dwarf streaming logic
///
/// All interactions with the MC layer that is used to build the debug
/// information binary representation are handled in this class.
class DwarfStreamer {
/// \defgroup MCObjects MC layer objects constructed by the streamer
/// @{
std::unique_ptr<MCRegisterInfo> MRI;
std::unique_ptr<MCAsmInfo> MAI;
std::unique_ptr<MCObjectFileInfo> MOFI;
std::unique_ptr<MCContext> MC;
MCAsmBackend *MAB; // Owned by MCStreamer
std::unique_ptr<MCInstrInfo> MII;
std::unique_ptr<MCSubtargetInfo> MSTI;
MCCodeEmitter *MCE; // Owned by MCStreamer
MCStreamer *MS; // Owned by AsmPrinter
std::unique_ptr<TargetMachine> TM;
std::unique_ptr<AsmPrinter> Asm;
/// @}
/// The file we stream the linked Dwarf to.
raw_fd_ostream &OutFile;
uint32_t RangesSectionSize;
uint32_t LocSectionSize;
uint32_t LineSectionSize;
uint32_t FrameSectionSize;
/// Emit the pubnames or pubtypes section contribution for \p
/// Unit into \p Sec. The data is provided in \p Names.
void emitPubSectionForUnit(MCSection *Sec, StringRef Name,
const CompileUnit &Unit,
const std::vector<CompileUnit::AccelInfo> &Names);
public:
DwarfStreamer(raw_fd_ostream &OutFile) : OutFile(OutFile) {}
bool init(Triple TheTriple);
/// Dump the file to the disk.
bool finish(const DebugMap &);
AsmPrinter &getAsmPrinter() const { return *Asm; }
/// Set the current output section to debug_info and change
/// the MC Dwarf version to \p DwarfVersion.
void switchToDebugInfoSection(unsigned DwarfVersion);
/// Emit the compilation unit header for \p Unit in the
/// debug_info section.
///
/// As a side effect, this also switches the current Dwarf version
/// of the MC layer to the one of U.getOrigUnit().
void emitCompileUnitHeader(CompileUnit &Unit);
/// Recursively emit the DIE tree rooted at \p Die.
void emitDIE(DIE &Die);
/// Emit the abbreviation table \p Abbrevs to the debug_abbrev section.
void emitAbbrevs(const std::vector<std::unique_ptr<DIEAbbrev>> &Abbrevs,
unsigned DwarfVersion);
/// Emit the string table described by \p Pool.
void emitStrings(const NonRelocatableStringpool &Pool);
/// Emit the swift_ast section stored in \p Buffer.
void emitSwiftAST(StringRef Buffer);
/// Emit debug_ranges for \p FuncRange by translating the
/// original \p Entries.
void emitRangesEntries(
int64_t UnitPcOffset, uint64_t OrigLowPc,
const FunctionIntervals::const_iterator &FuncRange,
const std::vector<DWARFDebugRangeList::RangeListEntry> &Entries,
unsigned AddressSize);
/// Emit debug_aranges entries for \p Unit and if \p DoRangesSection is true,
/// also emit the debug_ranges entries for the DW_TAG_compile_unit's
/// DW_AT_ranges attribute.
void emitUnitRangesEntries(CompileUnit &Unit, bool DoRangesSection);
uint32_t getRangesSectionSize() const { return RangesSectionSize; }
/// Emit the debug_loc contribution for \p Unit by copying the entries from
/// \p Dwarf and offsetting them. Update the location attributes to point to
/// the new entries.
void emitLocationsForUnit(const CompileUnit &Unit, DWARFContext &Dwarf);
/// Emit the line table described in \p Rows into the debug_line section.
void emitLineTableForUnit(MCDwarfLineTableParams Params,
StringRef PrologueBytes, unsigned MinInstLength,
std::vector<DWARFDebugLine::Row> &Rows,
unsigned AdddressSize);
/// Copy over the debug sections that are not modified when updating.
void copyInvariantDebugSection(const object::ObjectFile &Obj, LinkOptions &);
uint32_t getLineSectionSize() const { return LineSectionSize; }
/// Emit the .debug_pubnames contribution for \p Unit.
void emitPubNamesForUnit(const CompileUnit &Unit);
/// Emit the .debug_pubtypes contribution for \p Unit.
void emitPubTypesForUnit(const CompileUnit &Unit);
/// Emit a CIE.
void emitCIE(StringRef CIEBytes);
/// Emit an FDE with data \p Bytes.
void emitFDE(uint32_t CIEOffset, uint32_t AddreSize, uint32_t Address,
StringRef Bytes);
/// Emit Apple namespaces accelerator table.
void emitAppleNamespaces(AccelTable<AppleAccelTableStaticOffsetData> &Table);
/// Emit Apple names accelerator table.
void emitAppleNames(AccelTable<AppleAccelTableStaticOffsetData> &Table);
/// Emit Apple Objective-C accelerator table.
void emitAppleObjc(AccelTable<AppleAccelTableStaticOffsetData> &Table);
/// Emit Apple type accelerator table.
void emitAppleTypes(AccelTable<AppleAccelTableStaticTypeData> &Table);
uint32_t getFrameSectionSize() const { return FrameSectionSize; }
};
} // end anonymous namespace
bool DwarfStreamer::init(Triple TheTriple) {
std::string ErrorStr;
std::string TripleName;
StringRef Context = "dwarf streamer init";
// Get the target.
const Target *TheTarget =
TargetRegistry::lookupTarget(TripleName, TheTriple, ErrorStr);
if (!TheTarget)
return error(ErrorStr, Context);
TripleName = TheTriple.getTriple();
// Create all the MC Objects.
MRI.reset(TheTarget->createMCRegInfo(TripleName));
if (!MRI)
return error(Twine("no register info for target ") + TripleName, Context);
MAI.reset(TheTarget->createMCAsmInfo(*MRI, TripleName));
if (!MAI)
return error("no asm info for target " + TripleName, Context);
MOFI.reset(new MCObjectFileInfo);
MC.reset(new MCContext(MAI.get(), MRI.get(), MOFI.get()));
MOFI->InitMCObjectFileInfo(TheTriple, /*PIC*/ false, *MC);
MSTI.reset(TheTarget->createMCSubtargetInfo(TripleName, "", ""));
if (!MSTI)
return error("no subtarget info for target " + TripleName, Context);
MCTargetOptions Options;
MAB = TheTarget->createMCAsmBackend(*MSTI, *MRI, Options);
if (!MAB)
return error("no asm backend for target " + TripleName, Context);
MII.reset(TheTarget->createMCInstrInfo());
if (!MII)
return error("no instr info info for target " + TripleName, Context);
MCE = TheTarget->createMCCodeEmitter(*MII, *MRI, *MC);
if (!MCE)
return error("no code emitter for target " + TripleName, Context);
MCTargetOptions MCOptions = InitMCTargetOptionsFromFlags();
MS = TheTarget->createMCObjectStreamer(
TheTriple, *MC, std::unique_ptr<MCAsmBackend>(MAB), OutFile,
std::unique_ptr<MCCodeEmitter>(MCE), *MSTI, MCOptions.MCRelaxAll,
MCOptions.MCIncrementalLinkerCompatible,
/*DWARFMustBeAtTheEnd*/ false);
if (!MS)
return error("no object streamer for target " + TripleName, Context);
// Finally create the AsmPrinter we'll use to emit the DIEs.
TM.reset(TheTarget->createTargetMachine(TripleName, "", "", TargetOptions(),
None));
if (!TM)
return error("no target machine for target " + TripleName, Context);
Asm.reset(TheTarget->createAsmPrinter(*TM, std::unique_ptr<MCStreamer>(MS)));
if (!Asm)
return error("no asm printer for target " + TripleName, Context);
RangesSectionSize = 0;
LocSectionSize = 0;
LineSectionSize = 0;
FrameSectionSize = 0;
return true;
}
bool DwarfStreamer::finish(const DebugMap &DM) {
bool Result = true;
if (DM.getTriple().isOSDarwin() && !DM.getBinaryPath().empty())
Result = MachOUtils::generateDsymCompanion(DM, *MS, OutFile);
else
MS->Finish();
return Result;
}
void DwarfStreamer::switchToDebugInfoSection(unsigned DwarfVersion) {
MS->SwitchSection(MOFI->getDwarfInfoSection());
MC->setDwarfVersion(DwarfVersion);
}
/// Emit the compilation unit header for \p Unit in the debug_info section.
///
/// A Dwarf section header is encoded as:
/// uint32_t Unit length (omitting this field)
/// uint16_t Version
/// uint32_t Abbreviation table offset
/// uint8_t Address size
///
/// Leading to a total of 11 bytes.
void DwarfStreamer::emitCompileUnitHeader(CompileUnit &Unit) {
unsigned Version = Unit.getOrigUnit().getVersion();
switchToDebugInfoSection(Version);
// Emit size of content not including length itself. The size has already
// been computed in CompileUnit::computeOffsets(). Subtract 4 to that size to
// account for the length field.
Asm->emitInt32(Unit.getNextUnitOffset() - Unit.getStartOffset() - 4);
Asm->emitInt16(Version);
// We share one abbreviations table across all units so it's always at the
// start of the section.
Asm->emitInt32(0);
Asm->emitInt8(Unit.getOrigUnit().getAddressByteSize());
}
/// Emit the \p Abbrevs array as the shared abbreviation table
/// for the linked Dwarf file.
void DwarfStreamer::emitAbbrevs(
const std::vector<std::unique_ptr<DIEAbbrev>> &Abbrevs,
unsigned DwarfVersion) {
MS->SwitchSection(MOFI->getDwarfAbbrevSection());
MC->setDwarfVersion(DwarfVersion);
Asm->emitDwarfAbbrevs(Abbrevs);
}
/// Recursively emit the DIE tree rooted at \p Die.
void DwarfStreamer::emitDIE(DIE &Die) {
MS->SwitchSection(MOFI->getDwarfInfoSection());
Asm->emitDwarfDIE(Die);
}
/// Emit the debug_str section stored in \p Pool.
void DwarfStreamer::emitStrings(const NonRelocatableStringpool &Pool) {
Asm->OutStreamer->SwitchSection(MOFI->getDwarfStrSection());
std::vector<DwarfStringPoolEntryRef> Entries = Pool.getEntries();
for (auto Entry : Entries) {
if (Entry.getIndex() == -1U)
break;
// Emit the string itself.
Asm->OutStreamer->EmitBytes(Entry.getString());
// Emit a null terminator.
Asm->emitInt8(0);
}
}
void DwarfStreamer::emitAppleNamespaces(
AccelTable<AppleAccelTableStaticOffsetData> &Table) {
Asm->OutStreamer->SwitchSection(MOFI->getDwarfAccelNamespaceSection());
auto *SectionBegin = Asm->createTempSymbol("namespac_begin");
Asm->OutStreamer->EmitLabel(SectionBegin);
emitAppleAccelTable(Asm.get(), Table, "namespac", SectionBegin);
}
void DwarfStreamer::emitAppleNames(
AccelTable<AppleAccelTableStaticOffsetData> &Table) {
Asm->OutStreamer->SwitchSection(MOFI->getDwarfAccelNamesSection());
auto *SectionBegin = Asm->createTempSymbol("names_begin");
Asm->OutStreamer->EmitLabel(SectionBegin);
emitAppleAccelTable(Asm.get(), Table, "names", SectionBegin);
}
void DwarfStreamer::emitAppleObjc(
AccelTable<AppleAccelTableStaticOffsetData> &Table) {
Asm->OutStreamer->SwitchSection(MOFI->getDwarfAccelObjCSection());
auto *SectionBegin = Asm->createTempSymbol("objc_begin");
Asm->OutStreamer->EmitLabel(SectionBegin);
emitAppleAccelTable(Asm.get(), Table, "objc", SectionBegin);
}
void DwarfStreamer::emitAppleTypes(
AccelTable<AppleAccelTableStaticTypeData> &Table) {
Asm->OutStreamer->SwitchSection(MOFI->getDwarfAccelTypesSection());
auto *SectionBegin = Asm->createTempSymbol("types_begin");
Asm->OutStreamer->EmitLabel(SectionBegin);
emitAppleAccelTable(Asm.get(), Table, "types", SectionBegin);
}
/// Emit the swift_ast section stored in \p Buffers.
void DwarfStreamer::emitSwiftAST(StringRef Buffer) {
MCSection *SwiftASTSection = MOFI->getDwarfSwiftASTSection();
SwiftASTSection->setAlignment(1 << 5);
MS->SwitchSection(SwiftASTSection);
MS->EmitBytes(Buffer);
}
/// Emit the debug_range section contents for \p FuncRange by
/// translating the original \p Entries. The debug_range section
/// format is totally trivial, consisting just of pairs of address
/// sized addresses describing the ranges.
void DwarfStreamer::emitRangesEntries(
int64_t UnitPcOffset, uint64_t OrigLowPc,
const FunctionIntervals::const_iterator &FuncRange,
const std::vector<DWARFDebugRangeList::RangeListEntry> &Entries,
unsigned AddressSize) {
MS->SwitchSection(MC->getObjectFileInfo()->getDwarfRangesSection());
// Offset each range by the right amount.
int64_t PcOffset = Entries.empty() ? 0 : FuncRange.value() + UnitPcOffset;
for (const auto &Range : Entries) {
if (Range.isBaseAddressSelectionEntry(AddressSize)) {
warn("unsupported base address selection operation",
"emitting debug_ranges");
break;
}
// Do not emit empty ranges.
if (Range.StartAddress == Range.EndAddress)
continue;
// All range entries should lie in the function range.
if (!(Range.StartAddress + OrigLowPc >= FuncRange.start() &&
Range.EndAddress + OrigLowPc <= FuncRange.stop()))
warn("inconsistent range data.", "emitting debug_ranges");
MS->EmitIntValue(Range.StartAddress + PcOffset, AddressSize);
MS->EmitIntValue(Range.EndAddress + PcOffset, AddressSize);
RangesSectionSize += 2 * AddressSize;
}
// Add the terminator entry.
MS->EmitIntValue(0, AddressSize);
MS->EmitIntValue(0, AddressSize);
RangesSectionSize += 2 * AddressSize;
}
/// Emit the debug_aranges contribution of a unit and
/// if \p DoDebugRanges is true the debug_range contents for a
/// compile_unit level DW_AT_ranges attribute (Which are basically the
/// same thing with a different base address).
/// Just aggregate all the ranges gathered inside that unit.
void DwarfStreamer::emitUnitRangesEntries(CompileUnit &Unit,
bool DoDebugRanges) {
unsigned AddressSize = Unit.getOrigUnit().getAddressByteSize();
// Gather the ranges in a vector, so that we can simplify them. The
// IntervalMap will have coalesced the non-linked ranges, but here
// we want to coalesce the linked addresses.
std::vector<std::pair<uint64_t, uint64_t>> Ranges;
const auto &FunctionRanges = Unit.getFunctionRanges();
for (auto Range = FunctionRanges.begin(), End = FunctionRanges.end();
Range != End; ++Range)
Ranges.push_back(std::make_pair(Range.start() + Range.value(),
Range.stop() + Range.value()));
// The object addresses where sorted, but again, the linked
// addresses might end up in a different order.
llvm::sort(Ranges.begin(), Ranges.end());
if (!Ranges.empty()) {
MS->SwitchSection(MC->getObjectFileInfo()->getDwarfARangesSection());
MCSymbol *BeginLabel = Asm->createTempSymbol("Barange");
MCSymbol *EndLabel = Asm->createTempSymbol("Earange");
unsigned HeaderSize =
sizeof(int32_t) + // Size of contents (w/o this field
sizeof(int16_t) + // DWARF ARange version number
sizeof(int32_t) + // Offset of CU in the .debug_info section
sizeof(int8_t) + // Pointer Size (in bytes)
sizeof(int8_t); // Segment Size (in bytes)
unsigned TupleSize = AddressSize * 2;
unsigned Padding = OffsetToAlignment(HeaderSize, TupleSize);
Asm->EmitLabelDifference(EndLabel, BeginLabel, 4); // Arange length
Asm->OutStreamer->EmitLabel(BeginLabel);
Asm->emitInt16(dwarf::DW_ARANGES_VERSION); // Version number
Asm->emitInt32(Unit.getStartOffset()); // Corresponding unit's offset
Asm->emitInt8(AddressSize); // Address size
Asm->emitInt8(0); // Segment size
Asm->OutStreamer->emitFill(Padding, 0x0);
for (auto Range = Ranges.begin(), End = Ranges.end(); Range != End;
++Range) {
uint64_t RangeStart = Range->first;
MS->EmitIntValue(RangeStart, AddressSize);
while ((Range + 1) != End && Range->second == (Range + 1)->first)
++Range;
MS->EmitIntValue(Range->second - RangeStart, AddressSize);
}
// Emit terminator
Asm->OutStreamer->EmitIntValue(0, AddressSize);
Asm->OutStreamer->EmitIntValue(0, AddressSize);
Asm->OutStreamer->EmitLabel(EndLabel);
}
if (!DoDebugRanges)
return;
MS->SwitchSection(MC->getObjectFileInfo()->getDwarfRangesSection());
// Offset each range by the right amount.
int64_t PcOffset = -Unit.getLowPc();
// Emit coalesced ranges.
for (auto Range = Ranges.begin(), End = Ranges.end(); Range != End; ++Range) {
MS->EmitIntValue(Range->first + PcOffset, AddressSize);
while (Range + 1 != End && Range->second == (Range + 1)->first)
++Range;
MS->EmitIntValue(Range->second + PcOffset, AddressSize);
RangesSectionSize += 2 * AddressSize;
}
// Add the terminator entry.
MS->EmitIntValue(0, AddressSize);
MS->EmitIntValue(0, AddressSize);
RangesSectionSize += 2 * AddressSize;
}
/// Emit location lists for \p Unit and update attributes to point to the new
/// entries.
void DwarfStreamer::emitLocationsForUnit(const CompileUnit &Unit,
DWARFContext &Dwarf) {
const auto &Attributes = Unit.getLocationAttributes();
if (Attributes.empty())
return;
MS->SwitchSection(MC->getObjectFileInfo()->getDwarfLocSection());
unsigned AddressSize = Unit.getOrigUnit().getAddressByteSize();
const DWARFSection &InputSec = Dwarf.getDWARFObj().getLocSection();
DataExtractor Data(InputSec.Data, Dwarf.isLittleEndian(), AddressSize);
DWARFUnit &OrigUnit = Unit.getOrigUnit();
auto OrigUnitDie = OrigUnit.getUnitDIE(false);
int64_t UnitPcOffset = 0;
if (auto OrigLowPc = dwarf::toAddress(OrigUnitDie.find(dwarf::DW_AT_low_pc)))
UnitPcOffset = int64_t(*OrigLowPc) - Unit.getLowPc();
for (const auto &Attr : Attributes) {
uint32_t Offset = Attr.first.get();
Attr.first.set(LocSectionSize);
// This is the quantity to add to the old location address to get
// the correct address for the new one.
int64_t LocPcOffset = Attr.second + UnitPcOffset;
while (Data.isValidOffset(Offset)) {
uint64_t Low = Data.getUnsigned(&Offset, AddressSize);
uint64_t High = Data.getUnsigned(&Offset, AddressSize);
LocSectionSize += 2 * AddressSize;
if (Low == 0 && High == 0) {
Asm->OutStreamer->EmitIntValue(0, AddressSize);
Asm->OutStreamer->EmitIntValue(0, AddressSize);
break;
}
Asm->OutStreamer->EmitIntValue(Low + LocPcOffset, AddressSize);
Asm->OutStreamer->EmitIntValue(High + LocPcOffset, AddressSize);
uint64_t Length = Data.getU16(&Offset);
Asm->OutStreamer->EmitIntValue(Length, 2);
// Just copy the bytes over.
Asm->OutStreamer->EmitBytes(
StringRef(InputSec.Data.substr(Offset, Length)));
Offset += Length;
LocSectionSize += Length + 2;
}
}
}
void DwarfStreamer::emitLineTableForUnit(MCDwarfLineTableParams Params,
StringRef PrologueBytes,
unsigned MinInstLength,
std::vector<DWARFDebugLine::Row> &Rows,
unsigned PointerSize) {
// Switch to the section where the table will be emitted into.
MS->SwitchSection(MC->getObjectFileInfo()->getDwarfLineSection());
MCSymbol *LineStartSym = MC->createTempSymbol();
MCSymbol *LineEndSym = MC->createTempSymbol();
// The first 4 bytes is the total length of the information for this
// compilation unit (not including these 4 bytes for the length).
Asm->EmitLabelDifference(LineEndSym, LineStartSym, 4);
Asm->OutStreamer->EmitLabel(LineStartSym);
// Copy Prologue.
MS->EmitBytes(PrologueBytes);
LineSectionSize += PrologueBytes.size() + 4;
SmallString<128> EncodingBuffer;
raw_svector_ostream EncodingOS(EncodingBuffer);
if (Rows.empty()) {
// We only have the dummy entry, dsymutil emits an entry with a 0
// address in that case.
MCDwarfLineAddr::Encode(*MC, Params, std::numeric_limits<int64_t>::max(), 0,
EncodingOS);
MS->EmitBytes(EncodingOS.str());
LineSectionSize += EncodingBuffer.size();
MS->EmitLabel(LineEndSym);
return;
}
// Line table state machine fields
unsigned FileNum = 1;
unsigned LastLine = 1;
unsigned Column = 0;
unsigned IsStatement = 1;
unsigned Isa = 0;
uint64_t Address = -1ULL;
unsigned RowsSinceLastSequence = 0;
for (unsigned Idx = 0; Idx < Rows.size(); ++Idx) {
auto &Row = Rows[Idx];
int64_t AddressDelta;
if (Address == -1ULL) {
MS->EmitIntValue(dwarf::DW_LNS_extended_op, 1);
MS->EmitULEB128IntValue(PointerSize + 1);
MS->EmitIntValue(dwarf::DW_LNE_set_address, 1);
MS->EmitIntValue(Row.Address, PointerSize);
LineSectionSize += 2 + PointerSize + getULEB128Size(PointerSize + 1);
AddressDelta = 0;
} else {
AddressDelta = (Row.Address - Address) / MinInstLength;
}
// FIXME: code copied and transformed from MCDwarf.cpp::EmitDwarfLineTable.
// We should find a way to share this code, but the current compatibility
// requirement with classic dsymutil makes it hard. Revisit that once this
// requirement is dropped.
if (FileNum != Row.File) {
FileNum = Row.File;
MS->EmitIntValue(dwarf::DW_LNS_set_file, 1);
MS->EmitULEB128IntValue(FileNum);
LineSectionSize += 1 + getULEB128Size(FileNum);
}
if (Column != Row.Column) {
Column = Row.Column;
MS->EmitIntValue(dwarf::DW_LNS_set_column, 1);
MS->EmitULEB128IntValue(Column);
LineSectionSize += 1 + getULEB128Size(Column);
}
// FIXME: We should handle the discriminator here, but dsymutil doesn't
// consider it, thus ignore it for now.
if (Isa != Row.Isa) {
Isa = Row.Isa;
MS->EmitIntValue(dwarf::DW_LNS_set_isa, 1);
MS->EmitULEB128IntValue(Isa);
LineSectionSize += 1 + getULEB128Size(Isa);
}
if (IsStatement != Row.IsStmt) {
IsStatement = Row.IsStmt;
MS->EmitIntValue(dwarf::DW_LNS_negate_stmt, 1);
LineSectionSize += 1;
}
if (Row.BasicBlock) {
MS->EmitIntValue(dwarf::DW_LNS_set_basic_block, 1);
LineSectionSize += 1;
}
if (Row.PrologueEnd) {
MS->EmitIntValue(dwarf::DW_LNS_set_prologue_end, 1);
LineSectionSize += 1;
}
if (Row.EpilogueBegin) {
MS->EmitIntValue(dwarf::DW_LNS_set_epilogue_begin, 1);
LineSectionSize += 1;
}
int64_t LineDelta = int64_t(Row.Line) - LastLine;
if (!Row.EndSequence) {
MCDwarfLineAddr::Encode(*MC, Params, LineDelta, AddressDelta, EncodingOS);
MS->EmitBytes(EncodingOS.str());
LineSectionSize += EncodingBuffer.size();
EncodingBuffer.resize(0);
Address = Row.Address;
LastLine = Row.Line;
RowsSinceLastSequence++;
} else {
if (LineDelta) {
MS->EmitIntValue(dwarf::DW_LNS_advance_line, 1);
MS->EmitSLEB128IntValue(LineDelta);
LineSectionSize += 1 + getSLEB128Size(LineDelta);
}
if (AddressDelta) {
MS->EmitIntValue(dwarf::DW_LNS_advance_pc, 1);
MS->EmitULEB128IntValue(AddressDelta);
LineSectionSize += 1 + getULEB128Size(AddressDelta);
}
MCDwarfLineAddr::Encode(*MC, Params, std::numeric_limits<int64_t>::max(),
0, EncodingOS);
MS->EmitBytes(EncodingOS.str());
LineSectionSize += EncodingBuffer.size();
EncodingBuffer.resize(0);
Address = -1ULL;
LastLine = FileNum = IsStatement = 1;
RowsSinceLastSequence = Column = Isa = 0;
}
}
if (RowsSinceLastSequence) {
MCDwarfLineAddr::Encode(*MC, Params, std::numeric_limits<int64_t>::max(), 0,
EncodingOS);
MS->EmitBytes(EncodingOS.str());
LineSectionSize += EncodingBuffer.size();
EncodingBuffer.resize(0);
}
MS->EmitLabel(LineEndSym);
}
static void emitSectionContents(const object::ObjectFile &Obj,
StringRef SecName, MCStreamer *MS) {
StringRef Contents;
if (auto Sec = getSectionByName(Obj, SecName))
if (!Sec->getContents(Contents))
MS->EmitBytes(Contents);
}
void DwarfStreamer::copyInvariantDebugSection(const object::ObjectFile &Obj,
LinkOptions &Options) {
MS->SwitchSection(MC->getObjectFileInfo()->getDwarfLineSection());
emitSectionContents(Obj, "debug_line", MS);
MS->SwitchSection(MC->getObjectFileInfo()->getDwarfLocSection());
emitSectionContents(Obj, "debug_loc", MS);
MS->SwitchSection(MC->getObjectFileInfo()->getDwarfRangesSection());
emitSectionContents(Obj, "debug_ranges", MS);
MS->SwitchSection(MC->getObjectFileInfo()->getDwarfFrameSection());
emitSectionContents(Obj, "debug_frame", MS);
MS->SwitchSection(MC->getObjectFileInfo()->getDwarfARangesSection());
emitSectionContents(Obj, "debug_aranges", MS);
}
/// Emit the pubnames or pubtypes section contribution for \p
/// Unit into \p Sec. The data is provided in \p Names.
void DwarfStreamer::emitPubSectionForUnit(
MCSection *Sec, StringRef SecName, const CompileUnit &Unit,
const std::vector<CompileUnit::AccelInfo> &Names) {
if (Names.empty())
return;
// Start the dwarf pubnames section.
Asm->OutStreamer->SwitchSection(Sec);
MCSymbol *BeginLabel = Asm->createTempSymbol("pub" + SecName + "_begin");
MCSymbol *EndLabel = Asm->createTempSymbol("pub" + SecName + "_end");
bool HeaderEmitted = false;
// Emit the pubnames for this compilation unit.
for (const auto &Name : Names) {
if (Name.SkipPubSection)
continue;
if (!HeaderEmitted) {
// Emit the header.
Asm->EmitLabelDifference(EndLabel, BeginLabel, 4); // Length
Asm->OutStreamer->EmitLabel(BeginLabel);
Asm->emitInt16(dwarf::DW_PUBNAMES_VERSION); // Version
Asm->emitInt32(Unit.getStartOffset()); // Unit offset
Asm->emitInt32(Unit.getNextUnitOffset() - Unit.getStartOffset()); // Size
HeaderEmitted = true;
}
Asm->emitInt32(Name.Die->getOffset());
// Emit the string itself.
Asm->OutStreamer->EmitBytes(Name.Name.getString());
// Emit a null terminator.
Asm->emitInt8(0);
}
if (!HeaderEmitted)
return;
Asm->emitInt32(0); // End marker.
Asm->OutStreamer->EmitLabel(EndLabel);
}
/// Emit .debug_pubnames for \p Unit.
void DwarfStreamer::emitPubNamesForUnit(const CompileUnit &Unit) {
emitPubSectionForUnit(MC->getObjectFileInfo()->getDwarfPubNamesSection(),
"names", Unit, Unit.getPubnames());
}
/// Emit .debug_pubtypes for \p Unit.
void DwarfStreamer::emitPubTypesForUnit(const CompileUnit &Unit) {
emitPubSectionForUnit(MC->getObjectFileInfo()->getDwarfPubTypesSection(),
"types", Unit, Unit.getPubtypes());
}
/// Emit a CIE into the debug_frame section.
void DwarfStreamer::emitCIE(StringRef CIEBytes) {
MS->SwitchSection(MC->getObjectFileInfo()->getDwarfFrameSection());
MS->EmitBytes(CIEBytes);
FrameSectionSize += CIEBytes.size();
}
/// Emit a FDE into the debug_frame section. \p FDEBytes
/// contains the FDE data without the length, CIE offset and address
/// which will be replaced with the parameter values.
void DwarfStreamer::emitFDE(uint32_t CIEOffset, uint32_t AddrSize,
uint32_t Address, StringRef FDEBytes) {
MS->SwitchSection(MC->getObjectFileInfo()->getDwarfFrameSection());
MS->EmitIntValue(FDEBytes.size() + 4 + AddrSize, 4);
MS->EmitIntValue(CIEOffset, 4);
MS->EmitIntValue(Address, AddrSize);
MS->EmitBytes(FDEBytes);
FrameSectionSize += FDEBytes.size() + 8 + AddrSize;
}
namespace {
/// Partial address range for debug map objects. Besides an offset, only the
/// HighPC is stored. The structure is stored in a map where the LowPC is the
/// key.
struct DebugMapObjectRange {
/// Function HighPC.
uint64_t HighPC;
/// Offset to apply to the linked address.
int64_t Offset;
DebugMapObjectRange(uint64_t EndPC, int64_t Offset)
: HighPC(EndPC), Offset(Offset) {}
DebugMapObjectRange() : HighPC(0), Offset(0) {}
};
/// Map LowPC to DebugMapObjectRange.
using RangesTy = std::map<uint64_t, DebugMapObjectRange>;
using UnitListTy = std::vector<std::unique_ptr<CompileUnit>>;
/// The core of the Dwarf linking logic.
///
/// The link of the dwarf information from the object files will be
/// driven by the selection of 'root DIEs', which are DIEs that
/// describe variables or functions that are present in the linked
/// binary (and thus have entries in the debug map). All the debug
/// information that will be linked (the DIEs, but also the line
/// tables, ranges, ...) is derived from that set of root DIEs.
///
/// The root DIEs are identified because they contain relocations that
/// correspond to a debug map entry at specific places (the low_pc for
/// a function, the location for a variable). These relocations are
/// called ValidRelocs in the DwarfLinker and are gathered as a very
/// first step when we start processing a DebugMapObject.
class DwarfLinker {
public:
DwarfLinker(raw_fd_ostream &OutFile, const LinkOptions &Options)
: OutFile(OutFile), Options(Options) {}
/// Link the contents of the DebugMap.
bool link(const DebugMap &);
void reportWarning(const Twine &Warning, const DebugMapObject &DMO,
const DWARFDie *DIE = nullptr) const;
private:
/// Remembers the newest DWARF version we've seen in a unit.
void maybeUpdateMaxDwarfVersion(unsigned Version) {
if (MaxDwarfVersion < Version)
MaxDwarfVersion = Version;
}
/// Emit warnings as Dwarf compile units to leave a trail after linking.
bool emitPaperTrailWarnings(const DebugMapObject &DMO, const DebugMap &Map,
OffsetsStringPool &StringPool);
/// Keeps track of relocations.
class RelocationManager {
struct ValidReloc {
uint32_t Offset;
uint32_t Size;
uint64_t Addend;
const DebugMapObject::DebugMapEntry *Mapping;
ValidReloc(uint32_t Offset, uint32_t Size, uint64_t Addend,
const DebugMapObject::DebugMapEntry *Mapping)
: Offset(Offset), Size(Size), Addend(Addend), Mapping(Mapping) {}
bool operator<(const ValidReloc &RHS) const {
return Offset < RHS.Offset;
}
};
const DwarfLinker &Linker;
/// The valid relocations for the current DebugMapObject.
/// This vector is sorted by relocation offset.
std::vector<ValidReloc> ValidRelocs;
/// Index into ValidRelocs of the next relocation to consider. As we walk
/// the DIEs in acsending file offset and as ValidRelocs is sorted by file
/// offset, keeping this index up to date is all we have to do to have a
/// cheap lookup during the root DIE selection and during DIE cloning.
unsigned NextValidReloc = 0;
public:
RelocationManager(DwarfLinker &Linker) : Linker(Linker) {}
bool hasValidRelocs() const { return !ValidRelocs.empty(); }
/// Reset the NextValidReloc counter.
void resetValidRelocs() { NextValidReloc = 0; }
/// \defgroup FindValidRelocations Translate debug map into a list
/// of relevant relocations
///
/// @{
bool findValidRelocsInDebugInfo(const object::ObjectFile &Obj,
const DebugMapObject &DMO);
bool findValidRelocs(const object::SectionRef &Section,
const object::ObjectFile &Obj,
const DebugMapObject &DMO);
void findValidRelocsMachO(const object::SectionRef &Section,
const object::MachOObjectFile &Obj,
const DebugMapObject &DMO);
/// @}
bool hasValidRelocation(uint32_t StartOffset, uint32_t EndOffset,
CompileUnit::DIEInfo &Info);
bool applyValidRelocs(MutableArrayRef<char> Data, uint32_t BaseOffset,
bool isLittleEndian);
};
/// Keeps track of data associated with one object during linking.
struct LinkContext {
DebugMapObject &DMO;
BinaryHolder BinHolder;
const object::ObjectFile *ObjectFile;
RelocationManager RelocMgr;
std::unique_ptr<DWARFContext> DwarfContext;
RangesTy Ranges;
UnitListTy CompileUnits;
LinkContext(const DebugMap &Map, DwarfLinker &Linker, DebugMapObject &DMO,
bool Verbose = false)
: DMO(DMO), BinHolder(Verbose), RelocMgr(Linker) {
// Swift ASTs are not object files.
if (DMO.getType() == MachO::N_AST) {
ObjectFile = nullptr;
return;
}
auto ErrOrObj = Linker.loadObject(BinHolder, DMO, Map);
ObjectFile = ErrOrObj ? &*ErrOrObj : nullptr;
DwarfContext = ObjectFile ? DWARFContext::create(*ObjectFile) : nullptr;
}
/// Clear compile units and ranges.
void Clear() {
CompileUnits.clear();
Ranges.clear();
}
};
/// Called at the start of a debug object link.
void startDebugObject(LinkContext &Context);
/// Called at the end of a debug object link.
void endDebugObject(LinkContext &Context);
/// \defgroup FindRootDIEs Find DIEs corresponding to debug map entries.
///
/// @{
/// Recursively walk the \p DIE tree and look for DIEs to
/// keep. Store that information in \p CU's DIEInfo.
///
/// The return value indicates whether the DIE is incomplete.
bool lookForDIEsToKeep(RelocationManager &RelocMgr, RangesTy &Ranges,
UnitListTy &Units, const DWARFDie &DIE,
const DebugMapObject &DMO, CompileUnit &CU,
unsigned Flags);
/// If this compile unit is really a skeleton CU that points to a
/// clang module, register it in ClangModules and return true.
///
/// A skeleton CU is a CU without children, a DW_AT_gnu_dwo_name
/// pointing to the module, and a DW_AT_gnu_dwo_id with the module
/// hash.
bool registerModuleReference(const DWARFDie &CUDie, const DWARFUnit &Unit,
DebugMap &ModuleMap, const DebugMapObject &DMO,
RangesTy &Ranges,
OffsetsStringPool &OffsetsStringPool,
UniquingStringPool &UniquingStringPoolStringPool,
DeclContextTree &ODRContexts, unsigned &UnitID,
unsigned Indent = 0);
/// Recursively add the debug info in this clang module .pcm
/// file (and all the modules imported by it in a bottom-up fashion)
/// to Units.
Error loadClangModule(StringRef Filename, StringRef ModulePath,
StringRef ModuleName, uint64_t DwoId,
DebugMap &ModuleMap, const DebugMapObject &DMO,
RangesTy &Ranges, OffsetsStringPool &OffsetsStringPool,
UniquingStringPool &UniquingStringPool,
DeclContextTree &ODRContexts, unsigned &UnitID,
unsigned Indent = 0);
/// Flags passed to DwarfLinker::lookForDIEsToKeep
enum TraversalFlags {
TF_Keep = 1 << 0, ///< Mark the traversed DIEs as kept.
TF_InFunctionScope = 1 << 1, ///< Current scope is a function scope.
TF_DependencyWalk = 1 << 2, ///< Walking the dependencies of a kept DIE.
TF_ParentWalk = 1 << 3, ///< Walking up the parents of a kept DIE.
TF_ODR = 1 << 4, ///< Use the ODR while keeping dependents.
TF_SkipPC = 1 << 5, ///< Skip all location attributes.
};
/// Mark the passed DIE as well as all the ones it depends on as kept.
void keepDIEAndDependencies(RelocationManager &RelocMgr, RangesTy &Ranges,
UnitListTy &Units, const DWARFDie &DIE,
CompileUnit::DIEInfo &MyInfo,
const DebugMapObject &DMO, CompileUnit &CU,
bool UseODR);
unsigned shouldKeepDIE(RelocationManager &RelocMgr, RangesTy &Ranges,
const DWARFDie &DIE, const DebugMapObject &DMO,
CompileUnit &Unit, CompileUnit::DIEInfo &MyInfo,
unsigned Flags);
unsigned shouldKeepVariableDIE(RelocationManager &RelocMgr,
const DWARFDie &DIE, CompileUnit &Unit,
CompileUnit::DIEInfo &MyInfo, unsigned Flags);
unsigned shouldKeepSubprogramDIE(RelocationManager &RelocMgr,
RangesTy &Ranges, const DWARFDie &DIE,
const DebugMapObject &DMO, CompileUnit &Unit,
CompileUnit::DIEInfo &MyInfo,
unsigned Flags);
bool hasValidRelocation(uint32_t StartOffset, uint32_t EndOffset,
CompileUnit::DIEInfo &Info);
/// @}
/// \defgroup Linking Methods used to link the debug information
///
/// @{
class DIECloner {
DwarfLinker &Linker;
RelocationManager &RelocMgr;
/// Allocator used for all the DIEValue objects.
BumpPtrAllocator &DIEAlloc;
std::vector<std::unique_ptr<CompileUnit>> &CompileUnits;
LinkOptions Options;
public:
DIECloner(DwarfLinker &Linker, RelocationManager &RelocMgr,
BumpPtrAllocator &DIEAlloc,
std::vector<std::unique_ptr<CompileUnit>> &CompileUnits,
LinkOptions &Options)
: Linker(Linker), RelocMgr(RelocMgr), DIEAlloc(DIEAlloc),
CompileUnits(CompileUnits), Options(Options) {}
/// Recursively clone \p InputDIE into an tree of DIE objects
/// where useless (as decided by lookForDIEsToKeep()) bits have been
/// stripped out and addresses have been rewritten according to the
/// debug map.
///
/// \param OutOffset is the offset the cloned DIE in the output
/// compile unit.
/// \param PCOffset (while cloning a function scope) is the offset
/// applied to the entry point of the function to get the linked address.
/// \param Die the output DIE to use, pass NULL to create one.
/// \returns the root of the cloned tree or null if nothing was selected.
DIE *cloneDIE(const DWARFDie &InputDIE, const DebugMapObject &DMO,
CompileUnit &U, OffsetsStringPool &StringPool,
int64_t PCOffset, uint32_t OutOffset, unsigned Flags,
DIE *Die = nullptr);
/// Construct the output DIE tree by cloning the DIEs we
/// chose to keep above. If there are no valid relocs, then there's
/// nothing to clone/emit.
void cloneAllCompileUnits(DWARFContext &DwarfContext,
const DebugMapObject &DMO, RangesTy &Ranges,
OffsetsStringPool &StringPool);
private:
using AttributeSpec = DWARFAbbreviationDeclaration::AttributeSpec;
/// Information gathered and exchanged between the various
/// clone*Attributes helpers about the attributes of a particular DIE.
struct AttributesInfo {
/// Names.
DwarfStringPoolEntryRef Name, MangledName, NameWithoutTemplate;
/// Offsets in the string pool.
uint32_t NameOffset = 0;
uint32_t MangledNameOffset = 0;
/// Value of AT_low_pc in the input DIE
uint64_t OrigLowPc = std::numeric_limits<uint64_t>::max();
/// Value of AT_high_pc in the input DIE
uint64_t OrigHighPc = 0;
/// Offset to apply to PC addresses inside a function.
int64_t PCOffset = 0;
/// Does the DIE have a low_pc attribute?
bool HasLowPc = false;
/// Does the DIE have a ranges attribute?
bool HasRanges = false;
/// Is this DIE only a declaration?
bool IsDeclaration = false;
AttributesInfo() = default;
};
/// Helper for cloneDIE.
unsigned cloneAttribute(DIE &Die, const DWARFDie &InputDIE,
const DebugMapObject &DMO, CompileUnit &U,
OffsetsStringPool &StringPool,
const DWARFFormValue &Val,
const AttributeSpec AttrSpec, unsigned AttrSize,
AttributesInfo &AttrInfo);
/// Clone a string attribute described by \p AttrSpec and add
/// it to \p Die.
/// \returns the size of the new attribute.
unsigned cloneStringAttribute(DIE &Die, AttributeSpec AttrSpec,
const DWARFFormValue &Val, const DWARFUnit &U,
OffsetsStringPool &StringPool,
AttributesInfo &Info);
/// Clone an attribute referencing another DIE and add
/// it to \p Die.
/// \returns the size of the new attribute.
unsigned cloneDieReferenceAttribute(DIE &Die, const DWARFDie &InputDIE,
AttributeSpec AttrSpec,
unsigned AttrSize,
const DWARFFormValue &Val,
const DebugMapObject &DMO,
CompileUnit &Unit);
/// Clone an attribute referencing another DIE and add
/// it to \p Die.
/// \returns the size of the new attribute.
unsigned cloneBlockAttribute(DIE &Die, AttributeSpec AttrSpec,
const DWARFFormValue &Val, unsigned AttrSize);
/// Clone an attribute referencing another DIE and add
/// it to \p Die.
/// \returns the size of the new attribute.
unsigned cloneAddressAttribute(DIE &Die, AttributeSpec AttrSpec,
const DWARFFormValue &Val,
const CompileUnit &Unit,
AttributesInfo &Info);
/// Clone a scalar attribute and add it to \p Die.
/// \returns the size of the new attribute.
unsigned cloneScalarAttribute(DIE &Die, const DWARFDie &InputDIE,
const DebugMapObject &DMO, CompileUnit &U,
AttributeSpec AttrSpec,
const DWARFFormValue &Val, unsigned AttrSize,
AttributesInfo &Info);
/// Get the potential name and mangled name for the entity
/// described by \p Die and store them in \Info if they are not
/// already there.
/// \returns is a name was found.
bool getDIENames(const DWARFDie &Die, AttributesInfo &Info,
OffsetsStringPool &StringPool, bool StripTemplate = false);
/// Create a copy of abbreviation Abbrev.
void copyAbbrev(const DWARFAbbreviationDeclaration &Abbrev, bool hasODR);
uint32_t hashFullyQualifiedName(DWARFDie DIE, CompileUnit &U,
const DebugMapObject &DMO,
int RecurseDepth = 0);
/// Helper for cloneDIE.
void addObjCAccelerator(CompileUnit &Unit, const DIE *Die,
DwarfStringPoolEntryRef Name,
OffsetsStringPool &StringPool, bool SkipPubSection);
};
/// Assign an abbreviation number to \p Abbrev
void AssignAbbrev(DIEAbbrev &Abbrev);
/// Compute and emit debug_ranges section for \p Unit, and
/// patch the attributes referencing it.
void patchRangesForUnit(const CompileUnit &Unit, DWARFContext &Dwarf,
const DebugMapObject &DMO) const;
/// Generate and emit the DW_AT_ranges attribute for a compile_unit if it had
/// one.
void generateUnitRanges(CompileUnit &Unit) const;
/// Extract the line tables from the original dwarf, extract the relevant
/// parts according to the linked function ranges and emit the result in the
/// debug_line section.
void patchLineTableForUnit(CompileUnit &Unit, DWARFContext &OrigDwarf,
RangesTy &Ranges, const DebugMapObject &DMO);
/// Emit the accelerator entries for \p Unit.
void emitAcceleratorEntriesForUnit(CompileUnit &Unit);
/// Patch the frame info for an object file and emit it.
void patchFrameInfoForObject(const DebugMapObject &, RangesTy &Ranges,
DWARFContext &, unsigned AddressSize);
/// FoldingSet that uniques the abbreviations.
FoldingSet<DIEAbbrev> AbbreviationsSet;
/// Storage for the unique Abbreviations.
/// This is passed to AsmPrinter::emitDwarfAbbrevs(), thus it cannot be
/// changed to a vector of unique_ptrs.
std::vector<std::unique_ptr<DIEAbbrev>> Abbreviations;
/// DIELoc objects that need to be destructed (but not freed!).
std::vector<DIELoc *> DIELocs;
/// DIEBlock objects that need to be destructed (but not freed!).
std::vector<DIEBlock *> DIEBlocks;
/// Allocator used for all the DIEValue objects.
BumpPtrAllocator DIEAlloc;
/// @}
/// \defgroup Helpers Various helper methods.
///
/// @{
bool createStreamer(const Triple &TheTriple, raw_fd_ostream &OutFile);
/// Attempt to load a debug object from disk.
ErrorOr<const object::ObjectFile &> loadObject(BinaryHolder &BinaryHolder,
const DebugMapObject &Obj,
const DebugMap &Map);
/// @}
raw_fd_ostream &OutFile;
LinkOptions Options;
std::unique_ptr<DwarfStreamer> Streamer;
uint64_t OutputDebugInfoSize;
unsigned MaxDwarfVersion = 0;
/// The CIEs that have been emitted in the output section. The actual CIE
/// data serves a the key to this StringMap, this takes care of comparing the
/// semantics of CIEs defined in different object files.
StringMap<uint32_t> EmittedCIEs;
/// Offset of the last CIE that has been emitted in the output
/// debug_frame section.
uint32_t LastCIEOffset = 0;
/// Apple accelerator tables.
AccelTable<AppleAccelTableStaticOffsetData> AppleNames;
AccelTable<AppleAccelTableStaticOffsetData> AppleNamespaces;
AccelTable<AppleAccelTableStaticOffsetData> AppleObjc;
AccelTable<AppleAccelTableStaticTypeData> AppleTypes;
/// Mapping the PCM filename to the DwoId.
StringMap<uint64_t> ClangModules;
bool ModuleCacheHintDisplayed = false;
bool ArchiveHintDisplayed = false;
};
} // end anonymous namespace
/// Similar to DWARFUnitSection::getUnitForOffset(), but returning our
/// CompileUnit object instead.
static CompileUnit *
getUnitForOffset(std::vector<std::unique_ptr<CompileUnit>> &Units,
unsigned Offset) {
auto CU = std::upper_bound(
Units.begin(), Units.end(), Offset,
[](uint32_t LHS, const std::unique_ptr<CompileUnit> &RHS) {
return LHS < RHS->getOrigUnit().getNextUnitOffset();
});
return CU != Units.end() ? CU->get() : nullptr;
}
/// Resolve the DIE attribute reference that has been extracted in \p RefValue.
/// The resulting DIE might be in another CompileUnit which is stored into \p
/// ReferencedCU. \returns null if resolving fails for any reason.
static DWARFDie
resolveDIEReference(const DwarfLinker &Linker, const DebugMapObject &DMO,
std::vector<std::unique_ptr<CompileUnit>> &Units,
const DWARFFormValue &RefValue, const DWARFUnit &Unit,
const DWARFDie &DIE, CompileUnit *&RefCU) {
assert(RefValue.isFormClass(DWARFFormValue::FC_Reference));
uint64_t RefOffset = *RefValue.getAsReference();
if ((RefCU = getUnitForOffset(Units, RefOffset)))
if (const auto RefDie = RefCU->getOrigUnit().getDIEForOffset(RefOffset)) {
// In a file with broken references, an attribute might point to a NULL
// DIE.
if (!RefDie.isNULL())
return RefDie;
}
Linker.reportWarning("could not find referenced DIE", DMO, &DIE);
return DWARFDie();
}
/// \returns whether the passed \a Attr type might contain a DIE reference
/// suitable for ODR uniquing.
static bool isODRAttribute(uint16_t Attr) {
switch (Attr) {
default:
return false;
case dwarf::DW_AT_type:
case dwarf::DW_AT_containing_type:
case dwarf::DW_AT_specification:
case dwarf::DW_AT_abstract_origin:
case dwarf::DW_AT_import:
return true;
}
llvm_unreachable("Improper attribute.");
}
/// Set the last DIE/CU a context was seen in and, possibly invalidate the
/// context if it is ambiguous.
///
/// In the current implementation, we don't handle overloaded functions well,
/// because the argument types are not taken into account when computing the
/// DeclContext tree.
///
/// Some of this is mitigated byt using mangled names that do contain the
/// arguments types, but sometimes (e.g. with function templates) we don't have
/// that. In that case, just do not unique anything that refers to the contexts
/// we are not able to distinguish.
///
/// If a context that is not a namespace appears twice in the same CU, we know
/// it is ambiguous. Make it invalid.
bool DeclContext::setLastSeenDIE(CompileUnit &U, const DWARFDie &Die) {
if (LastSeenCompileUnitID == U.getUniqueID()) {
DWARFUnit &OrigUnit = U.getOrigUnit();
uint32_t FirstIdx = OrigUnit.getDIEIndex(LastSeenDIE);
U.getInfo(FirstIdx).Ctxt = nullptr;
return false;
}
LastSeenCompileUnitID = U.getUniqueID();
LastSeenDIE = Die;
return true;
}
PointerIntPair<DeclContext *, 1> DeclContextTree::getChildDeclContext(
DeclContext &Context, const DWARFDie &DIE, CompileUnit &U,
UniquingStringPool &StringPool, bool InClangModule) {
unsigned Tag = DIE.getTag();
// FIXME: dsymutil-classic compat: We should bail out here if we
// have a specification or an abstract_origin. We will get the
// parent context wrong here.
switch (Tag) {
default:
// By default stop gathering child contexts.
return PointerIntPair<DeclContext *, 1>(nullptr);
case dwarf::DW_TAG_module:
break;
case dwarf::DW_TAG_compile_unit:
return PointerIntPair<DeclContext *, 1>(&Context);
case dwarf::DW_TAG_subprogram:
// Do not unique anything inside CU local functions.
if ((Context.getTag() == dwarf::DW_TAG_namespace ||
Context.getTag() == dwarf::DW_TAG_compile_unit) &&
!dwarf::toUnsigned(DIE.find(dwarf::DW_AT_external), 0))
return PointerIntPair<DeclContext *, 1>(nullptr);
LLVM_FALLTHROUGH;
case dwarf::DW_TAG_member:
case dwarf::DW_TAG_namespace:
case dwarf::DW_TAG_structure_type:
case dwarf::DW_TAG_class_type:
case dwarf::DW_TAG_union_type:
case dwarf::DW_TAG_enumeration_type:
case dwarf::DW_TAG_typedef:
// Artificial things might be ambiguous, because they might be created on
// demand. For example implicitly defined constructors are ambiguous
// because of the way we identify contexts, and they won't be generated
// every time everywhere.
if (dwarf::toUnsigned(DIE.find(dwarf::DW_AT_artificial), 0))
return PointerIntPair<DeclContext *, 1>(nullptr);
break;
}
const char *Name = DIE.getName(DINameKind::LinkageName);
const char *ShortName = DIE.getName(DINameKind::ShortName);
StringRef NameRef;
StringRef ShortNameRef;
StringRef FileRef;
if (Name)
NameRef = StringPool.internString(Name);
else if (Tag == dwarf::DW_TAG_namespace)
// FIXME: For dsymutil-classic compatibility. I think uniquing within
// anonymous namespaces is wrong. There is no ODR guarantee there.
NameRef = StringPool.internString("(anonymous namespace)");
if (ShortName && ShortName != Name)
ShortNameRef = StringPool.internString(ShortName);
else
ShortNameRef = NameRef;
if (Tag != dwarf::DW_TAG_class_type && Tag != dwarf::DW_TAG_structure_type &&
Tag != dwarf::DW_TAG_union_type &&
Tag != dwarf::DW_TAG_enumeration_type && NameRef.empty())
return PointerIntPair<DeclContext *, 1>(nullptr);
unsigned Line = 0;
unsigned ByteSize = std::numeric_limits<uint32_t>::max();
if (!InClangModule) {
// Gather some discriminating data about the DeclContext we will be
// creating: File, line number and byte size. This shouldn't be necessary,
// because the ODR is just about names, but given that we do some
// approximations with overloaded functions and anonymous namespaces, use
// these additional data points to make the process safer.
//
// This is disabled for clang modules, because forward declarations of
// module-defined types do not have a file and line.
ByteSize = dwarf::toUnsigned(DIE.find(dwarf::DW_AT_byte_size),
std::numeric_limits<uint64_t>::max());
if (Tag != dwarf::DW_TAG_namespace || !Name) {
if (unsigned FileNum =
dwarf::toUnsigned(DIE.find(dwarf::DW_AT_decl_file), 0)) {
if (const auto *LT = U.getOrigUnit().getContext().getLineTableForUnit(
&U.getOrigUnit())) {
// FIXME: dsymutil-classic compatibility. I'd rather not
// unique anything in anonymous namespaces, but if we do, then
// verify that the file and line correspond.
if (!Name && Tag == dwarf::DW_TAG_namespace)
FileNum = 1;
if (LT->hasFileAtIndex(FileNum)) {
Line = dwarf::toUnsigned(DIE.find(dwarf::DW_AT_decl_line), 0);
// Cache the resolved paths based on the index in the line table,
// because calling realpath is expansive.
StringRef ResolvedPath = U.getResolvedPath(FileNum);
if (!ResolvedPath.empty()) {
FileRef = ResolvedPath;
} else {
std::string File;
bool FoundFileName = LT->getFileNameByIndex(
FileNum, U.getOrigUnit().getCompilationDir(),
DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath,
File);
(void)FoundFileName;
assert(FoundFileName && "Must get file name from line table");
// Second level of caching, this time based on the file's parent
// path.
FileRef = PathResolver.resolve(File, StringPool);
U.setResolvedPath(FileNum, FileRef);
}
}
}
}
}
}
if (!Line && NameRef.empty())
return PointerIntPair<DeclContext *, 1>(nullptr);
// We hash NameRef, which is the mangled name, in order to get most
// overloaded functions resolve correctly.
//
// Strictly speaking, hashing the Tag is only necessary for a
// DW_TAG_module, to prevent uniquing of a module and a namespace
// with the same name.
//
// FIXME: dsymutil-classic won't unique the same type presented
// once as a struct and once as a class. Using the Tag in the fully
// qualified name hash to get the same effect.
unsigned Hash = hash_combine(Context.getQualifiedNameHash(), Tag, NameRef);
// FIXME: dsymutil-classic compatibility: when we don't have a name,
// use the filename.
if (Tag == dwarf::DW_TAG_namespace && NameRef == "(anonymous namespace)")
Hash = hash_combine(Hash, FileRef);
// Now look if this context already exists.
DeclContext Key(Hash, Line, ByteSize, Tag, NameRef, FileRef, Context);
auto ContextIter = Contexts.find(&Key);
if (ContextIter == Contexts.end()) {
// The context wasn't found.
bool Inserted;
DeclContext *NewContext =
new (Allocator) DeclContext(Hash, Line, ByteSize, Tag, NameRef, FileRef,
Context, DIE, U.getUniqueID());
std::tie(ContextIter, Inserted) = Contexts.insert(NewContext);
assert(Inserted && "Failed to insert DeclContext");
(void)Inserted;
} else if (Tag != dwarf::DW_TAG_namespace &&
!(*ContextIter)->setLastSeenDIE(U, DIE)) {
// The context was found, but it is ambiguous with another context
// in the same file. Mark it invalid.
return PointerIntPair<DeclContext *, 1>(*ContextIter, /* Invalid= */ 1);
}
assert(ContextIter != Contexts.end());
// FIXME: dsymutil-classic compatibility. Union types aren't
// uniques, but their children might be.
if ((Tag == dwarf::DW_TAG_subprogram &&
Context.getTag() != dwarf::DW_TAG_structure_type &&
Context.getTag() != dwarf::DW_TAG_class_type) ||
(Tag == dwarf::DW_TAG_union_type))
return PointerIntPair<DeclContext *, 1>(*ContextIter, /* Invalid= */ 1);
return PointerIntPair<DeclContext *, 1>(*ContextIter);
}
bool DwarfLinker::DIECloner::getDIENames(const DWARFDie &Die,
AttributesInfo &Info,
OffsetsStringPool &StringPool,
bool StripTemplate) {
// This function will be called on DIEs having low_pcs and
// ranges. As getting the name might be more expansive, filter out
// blocks directly.
if (Die.getTag() == dwarf::DW_TAG_lexical_block)
return false;
// FIXME: a bit wasteful as the first getName might return the
// short name.
if (!Info.MangledName)
if (const char *MangledName = Die.getName(DINameKind::LinkageName))
Info.MangledName = StringPool.getEntry(MangledName);
if (!Info.Name)
if (const char *Name = Die.getName(DINameKind::ShortName))
Info.Name = StringPool.getEntry(Name);
if (StripTemplate && Info.Name && Info.MangledName != Info.Name) {
// FIXME: dsymutil compatibility. This is wrong for operator<
auto Split = Info.Name.getString().split('<');
if (!Split.second.empty())
Info.NameWithoutTemplate = StringPool.getEntry(Split.first);
}
return Info.Name || Info.MangledName;
}
/// Report a warning to the user, optionally including information about a
/// specific \p DIE related to the warning.
void DwarfLinker::reportWarning(const Twine &Warning, const DebugMapObject &DMO,
const DWARFDie *DIE) const {
StringRef Context = DMO.getObjectFilename();
warn(Warning, Context);
if (!Options.Verbose || !DIE)
return;
DIDumpOptions DumpOpts;
DumpOpts.RecurseDepth = 0;
DumpOpts.Verbose = Options.Verbose;
WithColor::note() << " in DIE:\n";
DIE->dump(errs(), 6 /* Indent */, DumpOpts);
}
bool DwarfLinker::createStreamer(const Triple &TheTriple,
raw_fd_ostream &OutFile) {
if (Options.NoOutput)
return true;
Streamer = llvm::make_unique<DwarfStreamer>(OutFile);
return Streamer->init(TheTriple);
}
/// Recursive helper to build the global DeclContext information and
/// gather the child->parent relationships in the original compile unit.
///
/// \return true when this DIE and all of its children are only
/// forward declarations to types defined in external clang modules
/// (i.e., forward declarations that are children of a DW_TAG_module).
static bool analyzeContextInfo(const DWARFDie &DIE, unsigned ParentIdx,
CompileUnit &CU, DeclContext *CurrentDeclContext,
UniquingStringPool &StringPool,
DeclContextTree &Contexts,
bool InImportedModule = false) {
unsigned MyIdx = CU.getOrigUnit().getDIEIndex(DIE);
CompileUnit::DIEInfo &Info = CU.getInfo(MyIdx);
// Clang imposes an ODR on modules(!) regardless of the language:
// "The module-id should consist of only a single identifier,
// which provides the name of the module being defined. Each
// module shall have a single definition."
//
// This does not extend to the types inside the modules:
// "[I]n C, this implies that if two structs are defined in
// different submodules with the same name, those two types are
// distinct types (but may be compatible types if their
// definitions match)."
//
// We treat non-C++ modules like namespaces for this reason.
if (DIE.getTag() == dwarf::DW_TAG_module && ParentIdx == 0 &&
dwarf::toString(DIE.find(dwarf::DW_AT_name), "") !=
CU.getClangModuleName()) {
InImportedModule = true;
}
Info.ParentIdx = ParentIdx;
bool InClangModule = CU.isClangModule() || InImportedModule;
if (CU.hasODR() || InClangModule) {
if (CurrentDeclContext) {
auto PtrInvalidPair = Contexts.getChildDeclContext(
*CurrentDeclContext, DIE, CU, StringPool, InClangModule);
CurrentDeclContext = PtrInvalidPair.getPointer();
Info.Ctxt =
PtrInvalidPair.getInt() ? nullptr : PtrInvalidPair.getPointer();
if (Info.Ctxt)
Info.Ctxt->setDefinedInClangModule(InClangModule);
} else
Info.Ctxt = CurrentDeclContext = nullptr;
}
Info.Prune = InImportedModule;
if (DIE.hasChildren())
for (auto Child : DIE.children())
Info.Prune &= analyzeContextInfo(Child, MyIdx, CU, CurrentDeclContext,
StringPool, Contexts, InImportedModule);
// Prune this DIE if it is either a forward declaration inside a
// DW_TAG_module or a DW_TAG_module that contains nothing but
// forward declarations.
Info.Prune &= (DIE.getTag() == dwarf::DW_TAG_module) ||
dwarf::toUnsigned(DIE.find(dwarf::DW_AT_declaration), 0);
// Don't prune it if there is no definition for the DIE.
Info.Prune &= Info.Ctxt && Info.Ctxt->getCanonicalDIEOffset();
return Info.Prune;
}
static bool dieNeedsChildrenToBeMeaningful(uint32_t Tag) {
switch (Tag) {
default:
return false;
case dwarf::DW_TAG_subprogram:
case dwarf::DW_TAG_lexical_block:
case dwarf::DW_TAG_subroutine_type:
case dwarf::DW_TAG_structure_type:
case dwarf::DW_TAG_class_type:
case dwarf::DW_TAG_union_type:
return true;
}
llvm_unreachable("Invalid Tag");
}
void DwarfLinker::startDebugObject(LinkContext &Context) {
// Iterate over the debug map entries and put all the ones that are
// functions (because they have a size) into the Ranges map. This map is
// very similar to the FunctionRanges that are stored in each unit, with 2
// notable differences:
//
// 1. Obviously this one is global, while the other ones are per-unit.
//
// 2. This one contains not only the functions described in the DIE
// tree, but also the ones that are only in the debug map.
//
// The latter information is required to reproduce dsymutil's logic while
// linking line tables. The cases where this information matters look like
// bugs that need to be investigated, but for now we need to reproduce
// dsymutil's behavior.
// FIXME: Once we understood exactly if that information is needed,
// maybe totally remove this (or try to use it to do a real
// -gline-tables-only on Darwin.
for (const auto &Entry : Context.DMO.symbols()) {
const auto &Mapping = Entry.getValue();
if (Mapping.Size && Mapping.ObjectAddress)
Context.Ranges[*Mapping.ObjectAddress] = DebugMapObjectRange(
*Mapping.ObjectAddress + Mapping.Size,
int64_t(Mapping.BinaryAddress) - *Mapping.ObjectAddress);
}
}
void DwarfLinker::endDebugObject(LinkContext &Context) {
Context.Clear();
for (auto I = DIEBlocks.begin(), E = DIEBlocks.end(); I != E; ++I)
(*I)->~DIEBlock();
for (auto I = DIELocs.begin(), E = DIELocs.end(); I != E; ++I)
(*I)->~DIELoc();
DIEBlocks.clear();
DIELocs.clear();
DIEAlloc.Reset();
}
static bool isMachOPairedReloc(uint64_t RelocType, uint64_t Arch) {
switch (Arch) {
case Triple::x86:
return RelocType == MachO::GENERIC_RELOC_SECTDIFF ||
RelocType == MachO::GENERIC_RELOC_LOCAL_SECTDIFF;
case Triple::x86_64:
return RelocType == MachO::X86_64_RELOC_SUBTRACTOR;
case Triple::arm:
case Triple::thumb:
return RelocType == MachO::ARM_RELOC_SECTDIFF ||
RelocType == MachO::ARM_RELOC_LOCAL_SECTDIFF ||
RelocType == MachO::ARM_RELOC_HALF ||
RelocType == MachO::ARM_RELOC_HALF_SECTDIFF;
case Triple::aarch64:
return RelocType == MachO::ARM64_RELOC_SUBTRACTOR;
default:
return false;
}
}
/// Iterate over the relocations of the given \p Section and
/// store the ones that correspond to debug map entries into the
/// ValidRelocs array.
void DwarfLinker::RelocationManager::findValidRelocsMachO(
const object::SectionRef &Section, const object::MachOObjectFile &Obj,
const DebugMapObject &DMO) {
StringRef Contents;
Section.getContents(Contents);
DataExtractor Data(Contents, Obj.isLittleEndian(), 0);
bool SkipNext = false;
for (const object::RelocationRef &Reloc : Section.relocations()) {
if (SkipNext) {
SkipNext = false;
continue;
}
object::DataRefImpl RelocDataRef = Reloc.getRawDataRefImpl();
MachO::any_relocation_info MachOReloc = Obj.getRelocation(RelocDataRef);
if (isMachOPairedReloc(Obj.getAnyRelocationType(MachOReloc),
Obj.getArch())) {
SkipNext = true;
Linker.reportWarning("unsupported relocation in debug_info section.",
DMO);
continue;
}
unsigned RelocSize = 1 << Obj.getAnyRelocationLength(MachOReloc);
uint64_t Offset64 = Reloc.getOffset();
if ((RelocSize != 4 && RelocSize != 8)) {
Linker.reportWarning("unsupported relocation in debug_info section.",
DMO);
continue;
}
uint32_t Offset = Offset64;
// Mach-o uses REL relocations, the addend is at the relocation offset.
uint64_t Addend = Data.getUnsigned(&Offset, RelocSize);
uint64_t SymAddress;
int64_t SymOffset;
if (Obj.isRelocationScattered(MachOReloc)) {
// The address of the base symbol for scattered relocations is
// stored in the reloc itself. The actual addend will store the
// base address plus the offset.
SymAddress = Obj.getScatteredRelocationValue(MachOReloc);
SymOffset = int64_t(Addend) - SymAddress;
} else {
SymAddress = Addend;
SymOffset = 0;
}
auto Sym = Reloc.getSymbol();
if (Sym != Obj.symbol_end()) {
Expected<StringRef> SymbolName = Sym->getName();
if (!SymbolName) {
consumeError(SymbolName.takeError());
Linker.reportWarning("error getting relocation symbol name.", DMO);
continue;
}
if (const auto *Mapping = DMO.lookupSymbol(*SymbolName))
ValidRelocs.emplace_back(Offset64, RelocSize, Addend, Mapping);
} else if (const auto *Mapping = DMO.lookupObjectAddress(SymAddress)) {
// Do not store the addend. The addend was the address of the symbol in
// the object file, the address in the binary that is stored in the debug
// map doesn't need to be offset.
ValidRelocs.emplace_back(Offset64, RelocSize, SymOffset, Mapping);
}
}
}
/// Dispatch the valid relocation finding logic to the
/// appropriate handler depending on the object file format.
bool DwarfLinker::RelocationManager::findValidRelocs(
const object::SectionRef &Section, const object::ObjectFile &Obj,
const DebugMapObject &DMO) {
// Dispatch to the right handler depending on the file type.
if (auto *MachOObj = dyn_cast<object::MachOObjectFile>(&Obj))
findValidRelocsMachO(Section, *MachOObj, DMO);
else
Linker.reportWarning(
Twine("unsupported object file type: ") + Obj.getFileName(), DMO);
if (ValidRelocs.empty())
return false;
// Sort the relocations by offset. We will walk the DIEs linearly in
// the file, this allows us to just keep an index in the relocation
// array that we advance during our walk, rather than resorting to
// some associative container. See DwarfLinker::NextValidReloc.
llvm::sort(ValidRelocs.begin(), ValidRelocs.end());
return true;
}
/// Look for relocations in the debug_info section that match
/// entries in the debug map. These relocations will drive the Dwarf
/// link by indicating which DIEs refer to symbols present in the
/// linked binary.
/// \returns whether there are any valid relocations in the debug info.
bool DwarfLinker::RelocationManager::findValidRelocsInDebugInfo(
const object::ObjectFile &Obj, const DebugMapObject &DMO) {
// Find the debug_info section.
for (const object::SectionRef &Section : Obj.sections()) {
StringRef SectionName;
Section.getName(SectionName);
SectionName = SectionName.substr(SectionName.find_first_not_of("._"));
if (SectionName != "debug_info")
continue;
return findValidRelocs(Section, Obj, DMO);
}
return false;
}
/// Checks that there is a relocation against an actual debug
/// map entry between \p StartOffset and \p NextOffset.
///
/// This function must be called with offsets in strictly ascending
/// order because it never looks back at relocations it already 'went past'.
/// \returns true and sets Info.InDebugMap if it is the case.
bool DwarfLinker::RelocationManager::hasValidRelocation(
uint32_t StartOffset, uint32_t EndOffset, CompileUnit::DIEInfo &Info) {
assert(NextValidReloc == 0 ||
StartOffset > ValidRelocs[NextValidReloc - 1].Offset);
if (NextValidReloc >= ValidRelocs.size())
return false;
uint64_t RelocOffset = ValidRelocs[NextValidReloc].Offset;
// We might need to skip some relocs that we didn't consider. For
// example the high_pc of a discarded DIE might contain a reloc that
// is in the list because it actually corresponds to the start of a
// function that is in the debug map.
while (RelocOffset < StartOffset && NextValidReloc < ValidRelocs.size() - 1)
RelocOffset = ValidRelocs[++NextValidReloc].Offset;
if (RelocOffset < StartOffset || RelocOffset >= EndOffset)
return false;
const auto &ValidReloc = ValidRelocs[NextValidReloc++];
const auto &Mapping = ValidReloc.Mapping->getValue();
uint64_t ObjectAddress = Mapping.ObjectAddress
? uint64_t(*Mapping.ObjectAddress)
: std::numeric_limits<uint64_t>::max();
if (Linker.Options.Verbose)
outs() << "Found valid debug map entry: " << ValidReloc.Mapping->getKey()
<< " "
<< format("\t%016" PRIx64 " => %016" PRIx64, ObjectAddress,
uint64_t(Mapping.BinaryAddress));
Info.AddrAdjust = int64_t(Mapping.BinaryAddress) + ValidReloc.Addend;
if (Mapping.ObjectAddress)
Info.AddrAdjust -= ObjectAddress;
Info.InDebugMap = true;
return true;
}
/// Get the starting and ending (exclusive) offset for the
/// attribute with index \p Idx descibed by \p Abbrev. \p Offset is
/// supposed to point to the position of the first attribute described
/// by \p Abbrev.
/// \return [StartOffset, EndOffset) as a pair.
static std::pair<uint32_t, uint32_t>
getAttributeOffsets(const DWARFAbbreviationDeclaration *Abbrev, unsigned Idx,
unsigned Offset, const DWARFUnit &Unit) {
DataExtractor Data = Unit.getDebugInfoExtractor();
for (unsigned i = 0; i < Idx; ++i)
DWARFFormValue::skipValue(Abbrev->getFormByIndex(i), Data, &Offset,
Unit.getFormParams());
uint32_t End = Offset;
DWARFFormValue::skipValue(Abbrev->getFormByIndex(Idx), Data, &End,
Unit.getFormParams());
return std::make_pair(Offset, End);
}
/// Check if a variable describing DIE should be kept.
/// \returns updated TraversalFlags.
unsigned DwarfLinker::shouldKeepVariableDIE(RelocationManager &RelocMgr,
const DWARFDie &DIE,
CompileUnit &Unit,
CompileUnit::DIEInfo &MyInfo,
unsigned Flags) {
const auto *Abbrev = DIE.getAbbreviationDeclarationPtr();
// Global variables with constant value can always be kept.
if (!(Flags & TF_InFunctionScope) &&
Abbrev->findAttributeIndex(dwarf::DW_AT_const_value)) {
MyInfo.InDebugMap = true;
return Flags | TF_Keep;
}
Optional<uint32_t> LocationIdx =
Abbrev->findAttributeIndex(dwarf::DW_AT_location);
if (!LocationIdx)
return Flags;
uint32_t Offset = DIE.getOffset() + getULEB128Size(Abbrev->getCode());
const DWARFUnit &OrigUnit = Unit.getOrigUnit();
uint32_t LocationOffset, LocationEndOffset;
std::tie(LocationOffset, LocationEndOffset) =
getAttributeOffsets(Abbrev, *LocationIdx, Offset, OrigUnit);
// See if there is a relocation to a valid debug map entry inside
// this variable's location. The order is important here. We want to
// always check in the variable has a valid relocation, so that the
// DIEInfo is filled. However, we don't want a static variable in a
// function to force us to keep the enclosing function.
if (!RelocMgr.hasValidRelocation(LocationOffset, LocationEndOffset, MyInfo) ||
(Flags & TF_InFunctionScope))
return Flags;
if (Options.Verbose) {
DIDumpOptions DumpOpts;
DumpOpts.RecurseDepth = 0;
DumpOpts.Verbose = Options.Verbose;
DIE.dump(outs(), 8 /* Indent */, DumpOpts);
}
return Flags | TF_Keep;
}
/// Check if a function describing DIE should be kept.
/// \returns updated TraversalFlags.
unsigned DwarfLinker::shouldKeepSubprogramDIE(
RelocationManager &RelocMgr, RangesTy &Ranges, const DWARFDie &DIE,
const DebugMapObject &DMO, CompileUnit &Unit, CompileUnit::DIEInfo &MyInfo,
unsigned Flags) {
const auto *Abbrev = DIE.getAbbreviationDeclarationPtr();
Flags |= TF_InFunctionScope;
Optional<uint32_t> LowPcIdx = Abbrev->findAttributeIndex(dwarf::DW_AT_low_pc);
if (!LowPcIdx)
return Flags;
uint32_t Offset = DIE.getOffset() + getULEB128Size(Abbrev->getCode());
DWARFUnit &OrigUnit = Unit.getOrigUnit();
uint32_t LowPcOffset, LowPcEndOffset;
std::tie(LowPcOffset, LowPcEndOffset) =
getAttributeOffsets(Abbrev, *LowPcIdx, Offset, OrigUnit);
auto LowPc = dwarf::toAddress(DIE.find(dwarf::DW_AT_low_pc));
assert(LowPc.hasValue() && "low_pc attribute is not an address.");
if (!LowPc ||
!RelocMgr.hasValidRelocation(LowPcOffset, LowPcEndOffset, MyInfo))
return Flags;
if (Options.Verbose) {
DIDumpOptions DumpOpts;
DumpOpts.RecurseDepth = 0;
DumpOpts.Verbose = Options.Verbose;
DIE.dump(outs(), 8 /* Indent */, DumpOpts);
}
if (DIE.getTag() == dwarf::DW_TAG_label) {
if (Unit.hasLabelAt(*LowPc))
return Flags;
// FIXME: dsymutil-classic compat. dsymutil-classic doesn't consider labels
// that don't fall into the CU's aranges. This is wrong IMO. Debug info
// generation bugs aside, this is really wrong in the case of labels, where
// a label marking the end of a function will have a PC == CU's high_pc.
if (dwarf::toAddress(OrigUnit.getUnitDIE().find(dwarf::DW_AT_high_pc))
.getValueOr(UINT64_MAX) <= LowPc)
return Flags;
Unit.addLabelLowPc(*LowPc, MyInfo.AddrAdjust);
return Flags | TF_Keep;
}
Flags |= TF_Keep;
Optional<uint64_t> HighPc = DIE.getHighPC(*LowPc);
if (!HighPc) {
reportWarning("Function without high_pc. Range will be discarded.\n", DMO,
&DIE);
return Flags;
}
// Replace the debug map range with a more accurate one.
Ranges[*LowPc] = DebugMapObjectRange(*HighPc, MyInfo.AddrAdjust);
Unit.addFunctionRange(*LowPc, *HighPc, MyInfo.AddrAdjust);
return Flags;
}
/// Check if a DIE should be kept.
/// \returns updated TraversalFlags.
unsigned DwarfLinker::shouldKeepDIE(RelocationManager &RelocMgr,
RangesTy &Ranges, const DWARFDie &DIE,
const DebugMapObject &DMO,
CompileUnit &Unit,
CompileUnit::DIEInfo &MyInfo,
unsigned Flags) {
switch (DIE.getTag()) {
case dwarf::DW_TAG_constant:
case dwarf::DW_TAG_variable:
return shouldKeepVariableDIE(RelocMgr, DIE, Unit, MyInfo, Flags);
case dwarf::DW_TAG_subprogram:
case dwarf::DW_TAG_label:
return shouldKeepSubprogramDIE(RelocMgr, Ranges, DIE, DMO, Unit, MyInfo,
Flags);
case dwarf::DW_TAG_imported_module:
case dwarf::DW_TAG_imported_declaration:
case dwarf::DW_TAG_imported_unit:
// We always want to keep these.
return Flags | TF_Keep;
default:
break;
}
return Flags;
}
/// Mark the passed DIE as well as all the ones it depends on
/// as kept.
///
/// This function is called by lookForDIEsToKeep on DIEs that are
/// newly discovered to be needed in the link. It recursively calls
/// back to lookForDIEsToKeep while adding TF_DependencyWalk to the
/// TraversalFlags to inform it that it's not doing the primary DIE
/// tree walk.
void DwarfLinker::keepDIEAndDependencies(RelocationManager &RelocMgr,
RangesTy &Ranges, UnitListTy &Units,
const DWARFDie &Die,
CompileUnit::DIEInfo &MyInfo,
const DebugMapObject &DMO,
CompileUnit &CU, bool UseODR) {
DWARFUnit &Unit = CU.getOrigUnit();
MyInfo.Keep = true;
// We're looking for incomplete types.
MyInfo.Incomplete = Die.getTag() != dwarf::DW_TAG_subprogram &&
Die.getTag() != dwarf::DW_TAG_member &&
dwarf::toUnsigned(Die.find(dwarf::DW_AT_declaration), 0);
// First mark all the parent chain as kept.
unsigned AncestorIdx = MyInfo.ParentIdx;
while (!CU.getInfo(AncestorIdx).Keep) {
unsigned ODRFlag = UseODR ? TF_ODR : 0;
lookForDIEsToKeep(RelocMgr, Ranges, Units, Unit.getDIEAtIndex(AncestorIdx),
DMO, CU,
TF_ParentWalk | TF_Keep | TF_DependencyWalk | ODRFlag);
AncestorIdx = CU.getInfo(AncestorIdx).ParentIdx;
}
// Then we need to mark all the DIEs referenced by this DIE's
// attributes as kept.
DWARFDataExtractor Data = Unit.getDebugInfoExtractor();
const auto *Abbrev = Die.getAbbreviationDeclarationPtr();
uint32_t Offset = Die.getOffset() + getULEB128Size(Abbrev->getCode());
// Mark all DIEs referenced through attributes as kept.
for (const auto &AttrSpec : Abbrev->attributes()) {
DWARFFormValue Val(AttrSpec.Form);
if (!Val.isFormClass(DWARFFormValue::FC_Reference) ||
AttrSpec.Attr == dwarf::DW_AT_sibling) {
DWARFFormValue::skipValue(AttrSpec.Form, Data, &Offset,
Unit.getFormParams());
continue;
}
Val.extractValue(Data, &Offset, Unit.getFormParams(), &Unit);
CompileUnit *ReferencedCU;
if (auto RefDie = resolveDIEReference(*this, DMO, Units, Val, Unit, Die,
ReferencedCU)) {
uint32_t RefIdx = ReferencedCU->getOrigUnit().getDIEIndex(RefDie);
CompileUnit::DIEInfo &Info = ReferencedCU->getInfo(RefIdx);
bool IsModuleRef = Info.Ctxt && Info.Ctxt->getCanonicalDIEOffset() &&
Info.Ctxt->isDefinedInClangModule();
// If the referenced DIE has a DeclContext that has already been
// emitted, then do not keep the one in this CU. We'll link to
// the canonical DIE in cloneDieReferenceAttribute.
// FIXME: compatibility with dsymutil-classic. UseODR shouldn't
// be necessary and could be advantageously replaced by
// ReferencedCU->hasODR() && CU.hasODR().
// FIXME: compatibility with dsymutil-classic. There is no
// reason not to unique ref_addr references.
if (AttrSpec.Form != dwarf::DW_FORM_ref_addr && (UseODR || IsModuleRef) &&
Info.Ctxt &&
Info.Ctxt != ReferencedCU->getInfo(Info.ParentIdx).Ctxt &&
Info.Ctxt->getCanonicalDIEOffset() && isODRAttribute(AttrSpec.Attr))
continue;
// Keep a module forward declaration if there is no definition.
if (!(isODRAttribute(AttrSpec.Attr) && Info.Ctxt &&
Info.Ctxt->getCanonicalDIEOffset()))
Info.Prune = false;
unsigned ODRFlag = UseODR ? TF_ODR : 0;
lookForDIEsToKeep(RelocMgr, Ranges, Units, RefDie, DMO, *ReferencedCU,
TF_Keep | TF_DependencyWalk | ODRFlag);
// The incomplete property is propagated if the current DIE is complete
// but references an incomplete DIE.
if (Info.Incomplete && !MyInfo.Incomplete &&
(Die.getTag() == dwarf::DW_TAG_typedef ||
Die.getTag() == dwarf::DW_TAG_member ||
Die.getTag() == dwarf::DW_TAG_reference_type ||
Die.getTag() == dwarf::DW_TAG_ptr_to_member_type ||
Die.getTag() == dwarf::DW_TAG_pointer_type))
MyInfo.Incomplete = true;
}
}
}
/// Recursively walk the \p DIE tree and look for DIEs to
/// keep. Store that information in \p CU's DIEInfo.
///
/// This function is the entry point of the DIE selection
/// algorithm. It is expected to walk the DIE tree in file order and
/// (though the mediation of its helper) call hasValidRelocation() on
/// each DIE that might be a 'root DIE' (See DwarfLinker class
/// comment).
/// While walking the dependencies of root DIEs, this function is
/// also called, but during these dependency walks the file order is
/// not respected. The TF_DependencyWalk flag tells us which kind of
/// traversal we are currently doing.
///
/// The return value indicates whether the DIE is incomplete.
bool DwarfLinker::lookForDIEsToKeep(RelocationManager &RelocMgr,
RangesTy &Ranges, UnitListTy &Units,
const DWARFDie &Die,
const DebugMapObject &DMO, CompileUnit &CU,
unsigned Flags) {
unsigned Idx = CU.getOrigUnit().getDIEIndex(Die);
CompileUnit::DIEInfo &MyInfo = CU.getInfo(Idx);
bool AlreadyKept = MyInfo.Keep;
if (MyInfo.Prune)
return true;
// If the Keep flag is set, we are marking a required DIE's
// dependencies. If our target is already marked as kept, we're all
// set.
if ((Flags & TF_DependencyWalk) && AlreadyKept)
return MyInfo.Incomplete;
// We must not call shouldKeepDIE while called from keepDIEAndDependencies,
// because it would screw up the relocation finding logic.
if (!(Flags & TF_DependencyWalk))
Flags = shouldKeepDIE(RelocMgr, Ranges, Die, DMO, CU, MyInfo, Flags);
// If it is a newly kept DIE mark it as well as all its dependencies as kept.
if (!AlreadyKept && (Flags & TF_Keep)) {
bool UseOdr = (Flags & TF_DependencyWalk) ? (Flags & TF_ODR) : CU.hasODR();
keepDIEAndDependencies(RelocMgr, Ranges, Units, Die, MyInfo, DMO, CU,
UseOdr);
}
// The TF_ParentWalk flag tells us that we are currently walking up
// the parent chain of a required DIE, and we don't want to mark all
// the children of the parents as kept (consider for example a
// DW_TAG_namespace node in the parent chain). There are however a
// set of DIE types for which we want to ignore that directive and still
// walk their children.
if (dieNeedsChildrenToBeMeaningful(Die.getTag()))
Flags &= ~TF_ParentWalk;
if (!Die.hasChildren() || (Flags & TF_ParentWalk))
return MyInfo.Incomplete;
bool Incomplete = false;
for (auto Child : Die.children()) {
Incomplete |=
lookForDIEsToKeep(RelocMgr, Ranges, Units, Child, DMO, CU, Flags);
// If any of the members are incomplete we propagate the incompleteness.
if (!MyInfo.Incomplete && Incomplete &&
(Die.getTag() == dwarf::DW_TAG_structure_type ||
Die.getTag() == dwarf::DW_TAG_class_type))
MyInfo.Incomplete = true;
}
return MyInfo.Incomplete;
}
/// Assign an abbreviation number to \p Abbrev.
///
/// Our DIEs get freed after every DebugMapObject has been processed,
/// thus the FoldingSet we use to unique DIEAbbrevs cannot refer to
/// the instances hold by the DIEs. When we encounter an abbreviation
/// that we don't know, we create a permanent copy of it.
void DwarfLinker::AssignAbbrev(DIEAbbrev &Abbrev) {
// Check the set for priors.
FoldingSetNodeID ID;
Abbrev.Profile(ID);
void *InsertToken;
DIEAbbrev *InSet = AbbreviationsSet.FindNodeOrInsertPos(ID, InsertToken);
// If it's newly added.
if (InSet) {
// Assign existing abbreviation number.
Abbrev.setNumber(InSet->getNumber());
} else {
// Add to abbreviation list.
Abbreviations.push_back(
llvm::make_unique<DIEAbbrev>(Abbrev.getTag(), Abbrev.hasChildren()));
for (const auto &Attr : Abbrev.getData())
Abbreviations.back()->AddAttribute(Attr.getAttribute(), Attr.getForm());
AbbreviationsSet.InsertNode(Abbreviations.back().get(), InsertToken);
// Assign the unique abbreviation number.
Abbrev.setNumber(Abbreviations.size());
Abbreviations.back()->setNumber(Abbreviations.size());
}
}
unsigned DwarfLinker::DIECloner::cloneStringAttribute(
DIE &Die, AttributeSpec AttrSpec, const DWARFFormValue &Val,
const DWARFUnit &U, OffsetsStringPool &StringPool, AttributesInfo &Info) {
// Switch everything to out of line strings.
const char *String = *Val.getAsCString();
auto StringEntry = StringPool.getEntry(String);
// Update attributes info.
if (AttrSpec.Attr == dwarf::DW_AT_name)
Info.Name = StringEntry;
else if (AttrSpec.Attr == dwarf::DW_AT_MIPS_linkage_name ||
AttrSpec.Attr == dwarf::DW_AT_linkage_name)
Info.MangledName = StringEntry;
Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr), dwarf::DW_FORM_strp,
DIEInteger(StringEntry.getOffset()));
return 4;
}
unsigned DwarfLinker::DIECloner::cloneDieReferenceAttribute(
DIE &Die, const DWARFDie &InputDIE, AttributeSpec AttrSpec,
unsigned AttrSize, const DWARFFormValue &Val, const DebugMapObject &DMO,
CompileUnit &Unit) {
const DWARFUnit &U = Unit.getOrigUnit();
uint32_t Ref = *Val.getAsReference();
DIE *NewRefDie = nullptr;
CompileUnit *RefUnit = nullptr;
DeclContext *Ctxt = nullptr;
DWARFDie RefDie =
resolveDIEReference(Linker, DMO, CompileUnits, Val, U, InputDIE, RefUnit);
// If the referenced DIE is not found, drop the attribute.
if (!RefDie || AttrSpec.Attr == dwarf::DW_AT_sibling)
return 0;
unsigned Idx = RefUnit->getOrigUnit().getDIEIndex(RefDie);
CompileUnit::DIEInfo &RefInfo = RefUnit->getInfo(Idx);
// If we already have emitted an equivalent DeclContext, just point
// at it.
if (isODRAttribute(AttrSpec.Attr)) {
Ctxt = RefInfo.Ctxt;
if (Ctxt && Ctxt->getCanonicalDIEOffset()) {
DIEInteger Attr(Ctxt->getCanonicalDIEOffset());
Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr),
dwarf::DW_FORM_ref_addr, Attr);
return U.getRefAddrByteSize();
}
}
if (!RefInfo.Clone) {
assert(Ref > InputDIE.getOffset());
// We haven't cloned this DIE yet. Just create an empty one and
// store it. It'll get really cloned when we process it.
RefInfo.Clone = DIE::get(DIEAlloc, dwarf::Tag(RefDie.getTag()));
}
NewRefDie = RefInfo.Clone;
if (AttrSpec.Form == dwarf::DW_FORM_ref_addr ||
(Unit.hasODR() && isODRAttribute(AttrSpec.Attr))) {
// We cannot currently rely on a DIEEntry to emit ref_addr
// references, because the implementation calls back to DwarfDebug
// to find the unit offset. (We don't have a DwarfDebug)
// FIXME: we should be able to design DIEEntry reliance on
// DwarfDebug away.
uint64_t Attr;
if (Ref < InputDIE.getOffset()) {
// We must have already cloned that DIE.
uint32_t NewRefOffset =
RefUnit->getStartOffset() + NewRefDie->getOffset();
Attr = NewRefOffset;
Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr),
dwarf::DW_FORM_ref_addr, DIEInteger(Attr));
} else {
// A forward reference. Note and fixup later.
Attr = 0xBADDEF;
Unit.noteForwardReference(
NewRefDie, RefUnit, Ctxt,
Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr),
dwarf::DW_FORM_ref_addr, DIEInteger(Attr)));
}
return U.getRefAddrByteSize();
}
Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr),
dwarf::Form(AttrSpec.Form), DIEEntry(*NewRefDie));
return AttrSize;
}
unsigned DwarfLinker::DIECloner::cloneBlockAttribute(DIE &Die,
AttributeSpec AttrSpec,
const DWARFFormValue &Val,
unsigned AttrSize) {
DIEValueList *Attr;
DIEValue Value;
DIELoc *Loc = nullptr;
DIEBlock *Block = nullptr;
// Just copy the block data over.
if (AttrSpec.Form == dwarf::DW_FORM_exprloc) {
Loc = new (DIEAlloc) DIELoc;
Linker.DIELocs.push_back(Loc);
} else {
Block = new (DIEAlloc) DIEBlock;
Linker.DIEBlocks.push_back(Block);
}
Attr = Loc ? static_cast<DIEValueList *>(Loc)
: static_cast<DIEValueList *>(Block);
if (Loc)
Value = DIEValue(dwarf::Attribute(AttrSpec.Attr),
dwarf::Form(AttrSpec.Form), Loc);
else
Value = DIEValue(dwarf::Attribute(AttrSpec.Attr),
dwarf::Form(AttrSpec.Form), Block);
ArrayRef<uint8_t> Bytes = *Val.getAsBlock();
for (auto Byte : Bytes)
Attr->addValue(DIEAlloc, static_cast<dwarf::Attribute>(0),
dwarf::DW_FORM_data1, DIEInteger(Byte));
// FIXME: If DIEBlock and DIELoc just reuses the Size field of
// the DIE class, this if could be replaced by
// Attr->setSize(Bytes.size()).
if (Linker.Streamer) {
auto *AsmPrinter = &Linker.Streamer->getAsmPrinter();
if (Loc)
Loc->ComputeSize(AsmPrinter);
else
Block->ComputeSize(AsmPrinter);
}
Die.addValue(DIEAlloc, Value);
return AttrSize;
}
unsigned DwarfLinker::DIECloner::cloneAddressAttribute(
DIE &Die, AttributeSpec AttrSpec, const DWARFFormValue &Val,
const CompileUnit &Unit, AttributesInfo &Info) {
uint64_t Addr = *Val.getAsAddress();
if (LLVM_UNLIKELY(Linker.Options.Update)) {
if (AttrSpec.Attr == dwarf::DW_AT_low_pc)
Info.HasLowPc = true;
Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr),
dwarf::Form(AttrSpec.Form), DIEInteger(Addr));
return Unit.getOrigUnit().getAddressByteSize();
}
if (AttrSpec.Attr == dwarf::DW_AT_low_pc) {
if (Die.getTag() == dwarf::DW_TAG_inlined_subroutine ||
Die.getTag() == dwarf::DW_TAG_lexical_block)
// The low_pc of a block or inline subroutine might get
// relocated because it happens to match the low_pc of the
// enclosing subprogram. To prevent issues with that, always use
// the low_pc from the input DIE if relocations have been applied.
Addr = (Info.OrigLowPc != std::numeric_limits<uint64_t>::max()
? Info.OrigLowPc
: Addr) +
Info.PCOffset;
else if (Die.getTag() == dwarf::DW_TAG_compile_unit) {
Addr = Unit.getLowPc();
if (Addr == std::numeric_limits<uint64_t>::max())
return 0;
}
Info.HasLowPc = true;
} else if (AttrSpec.Attr == dwarf::DW_AT_high_pc) {
if (Die.getTag() == dwarf::DW_TAG_compile_unit) {
if (uint64_t HighPc = Unit.getHighPc())
Addr = HighPc;
else
return 0;
} else
// If we have a high_pc recorded for the input DIE, use
// it. Otherwise (when no relocations where applied) just use the
// one we just decoded.
Addr = (Info.OrigHighPc ? Info.OrigHighPc : Addr) + Info.PCOffset;
}
Die.addValue(DIEAlloc, static_cast<dwarf::Attribute>(AttrSpec.Attr),
static_cast<dwarf::Form>(AttrSpec.Form), DIEInteger(Addr));
return Unit.getOrigUnit().getAddressByteSize();
}
unsigned DwarfLinker::DIECloner::cloneScalarAttribute(
DIE &Die, const DWARFDie &InputDIE, const DebugMapObject &DMO,
CompileUnit &Unit, AttributeSpec AttrSpec, const DWARFFormValue &Val,
unsigned AttrSize, AttributesInfo &Info) {
uint64_t Value;
if (LLVM_UNLIKELY(Linker.Options.Update)) {
if (auto OptionalValue = Val.getAsUnsignedConstant())
Value = *OptionalValue;
else if (auto OptionalValue = Val.getAsSignedConstant())
Value = *OptionalValue;
else if (auto OptionalValue = Val.getAsSectionOffset())
Value = *OptionalValue;
else {
Linker.reportWarning(
"Unsupported scalar attribute form. Dropping attribute.", DMO,
&InputDIE);
return 0;
}
if (AttrSpec.Attr == dwarf::DW_AT_declaration && Value)
Info.IsDeclaration = true;
Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr),
dwarf::Form(AttrSpec.Form), DIEInteger(Value));
return AttrSize;
}
if (AttrSpec.Attr == dwarf::DW_AT_high_pc &&
Die.getTag() == dwarf::DW_TAG_compile_unit) {
if (Unit.getLowPc() == -1ULL)
return 0;
// Dwarf >= 4 high_pc is an size, not an address.
Value = Unit.getHighPc() - Unit.getLowPc();
} else if (AttrSpec.Form == dwarf::DW_FORM_sec_offset)
Value = *Val.getAsSectionOffset();
else if (AttrSpec.Form == dwarf::DW_FORM_sdata)
Value = *Val.getAsSignedConstant();
else if (auto OptionalValue = Val.getAsUnsignedConstant())
Value = *OptionalValue;
else {
Linker.reportWarning(
"Unsupported scalar attribute form. Dropping attribute.", DMO,
&InputDIE);
return 0;
}
PatchLocation Patch =
Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr),
dwarf::Form(AttrSpec.Form), DIEInteger(Value));
if (AttrSpec.Attr == dwarf::DW_AT_ranges) {
Unit.noteRangeAttribute(Die, Patch);
Info.HasRanges = true;
}
// A more generic way to check for location attributes would be
// nice, but it's very unlikely that any other attribute needs a
// location list.
else if (AttrSpec.Attr == dwarf::DW_AT_location ||
AttrSpec.Attr == dwarf::DW_AT_frame_base)
Unit.noteLocationAttribute(Patch, Info.PCOffset);
else if (AttrSpec.Attr == dwarf::DW_AT_declaration && Value)
Info.IsDeclaration = true;
return AttrSize;
}
/// Clone \p InputDIE's attribute described by \p AttrSpec with
/// value \p Val, and add it to \p Die.
/// \returns the size of the cloned attribute.
unsigned DwarfLinker::DIECloner::cloneAttribute(
DIE &Die, const DWARFDie &InputDIE, const DebugMapObject &DMO,
CompileUnit &Unit, OffsetsStringPool &StringPool, const DWARFFormValue &Val,
const AttributeSpec AttrSpec, unsigned AttrSize, AttributesInfo &Info) {
const DWARFUnit &U = Unit.getOrigUnit();
switch (AttrSpec.Form) {
case dwarf::DW_FORM_strp:
case dwarf::DW_FORM_string:
return cloneStringAttribute(Die, AttrSpec, Val, U, StringPool, Info);
case dwarf::DW_FORM_ref_addr:
case dwarf::DW_FORM_ref1:
case dwarf::DW_FORM_ref2:
case dwarf::DW_FORM_ref4:
case dwarf::DW_FORM_ref8:
return cloneDieReferenceAttribute(Die, InputDIE, AttrSpec, AttrSize, Val,
DMO, Unit);
case dwarf::DW_FORM_block:
case dwarf::DW_FORM_block1:
case dwarf::DW_FORM_block2:
case dwarf::DW_FORM_block4:
case dwarf::DW_FORM_exprloc:
return cloneBlockAttribute(Die, AttrSpec, Val, AttrSize);
case dwarf::DW_FORM_addr:
return cloneAddressAttribute(Die, AttrSpec, Val, Unit, Info);
case dwarf::DW_FORM_data1:
case dwarf::DW_FORM_data2:
case dwarf::DW_FORM_data4:
case dwarf::DW_FORM_data8:
case dwarf::DW_FORM_udata:
case dwarf::DW_FORM_sdata:
case dwarf::DW_FORM_sec_offset:
case dwarf::DW_FORM_flag:
case dwarf::DW_FORM_flag_present:
return cloneScalarAttribute(Die, InputDIE, DMO, Unit, AttrSpec, Val,
AttrSize, Info);
default:
Linker.reportWarning(
"Unsupported attribute form in cloneAttribute. Dropping.", DMO,
&InputDIE);
}
return 0;
}
/// Apply the valid relocations found by findValidRelocs() to
/// the buffer \p Data, taking into account that Data is at \p BaseOffset
/// in the debug_info section.
///
/// Like for findValidRelocs(), this function must be called with
/// monotonic \p BaseOffset values.
///
/// \returns whether any reloc has been applied.
bool DwarfLinker::RelocationManager::applyValidRelocs(
MutableArrayRef<char> Data, uint32_t BaseOffset, bool isLittleEndian) {
assert((NextValidReloc == 0 ||
BaseOffset > ValidRelocs[NextValidReloc - 1].Offset) &&
"BaseOffset should only be increasing.");
if (NextValidReloc >= ValidRelocs.size())
return false;
// Skip relocs that haven't been applied.
while (NextValidReloc < ValidRelocs.size() &&
ValidRelocs[NextValidReloc].Offset < BaseOffset)
++NextValidReloc;
bool Applied = false;
uint64_t EndOffset = BaseOffset + Data.size();
while (NextValidReloc < ValidRelocs.size() &&
ValidRelocs[NextValidReloc].Offset >= BaseOffset &&
ValidRelocs[NextValidReloc].Offset < EndOffset) {
const auto &ValidReloc = ValidRelocs[NextValidReloc++];
assert(ValidReloc.Offset - BaseOffset < Data.size());
assert(ValidReloc.Offset - BaseOffset + ValidReloc.Size <= Data.size());
char Buf[8];
uint64_t Value = ValidReloc.Mapping->getValue().BinaryAddress;
Value += ValidReloc.Addend;
for (unsigned i = 0; i != ValidReloc.Size; ++i) {
unsigned Index = isLittleEndian ? i : (ValidReloc.Size - i - 1);
Buf[i] = uint8_t(Value >> (Index * 8));
}
assert(ValidReloc.Size <= sizeof(Buf));
memcpy(&Data[ValidReloc.Offset - BaseOffset], Buf, ValidReloc.Size);
Applied = true;
}
return Applied;
}
static bool isTypeTag(uint16_t Tag) {
switch (Tag) {
case dwarf::DW_TAG_array_type:
case dwarf::DW_TAG_class_type:
case dwarf::DW_TAG_enumeration_type:
case dwarf::DW_TAG_pointer_type:
case dwarf::DW_TAG_reference_type:
case dwarf::DW_TAG_string_type:
case dwarf::DW_TAG_structure_type:
case dwarf::DW_TAG_subroutine_type:
case dwarf::DW_TAG_typedef:
case dwarf::DW_TAG_union_type:
case dwarf::DW_TAG_ptr_to_member_type:
case dwarf::DW_TAG_set_type:
case dwarf::DW_TAG_subrange_type:
case dwarf::DW_TAG_base_type:
case dwarf::DW_TAG_const_type:
case dwarf::DW_TAG_constant:
case dwarf::DW_TAG_file_type:
case dwarf::DW_TAG_namelist:
case dwarf::DW_TAG_packed_type:
case dwarf::DW_TAG_volatile_type:
case dwarf::DW_TAG_restrict_type:
case dwarf::DW_TAG_atomic_type:
case dwarf::DW_TAG_interface_type:
case dwarf::DW_TAG_unspecified_type:
case dwarf::DW_TAG_shared_type:
return true;
default:
break;
}
return false;
}
static bool isObjCSelector(StringRef Name) {
return Name.size() > 2 && (Name[0] == '-' || Name[0] == '+') &&
(Name[1] == '[');
}
void DwarfLinker::DIECloner::addObjCAccelerator(CompileUnit &Unit,
const DIE *Die,
DwarfStringPoolEntryRef Name,
OffsetsStringPool &StringPool,
bool SkipPubSection) {
assert(isObjCSelector(Name.getString()) && "not an objc selector");
// Objective C method or class function.
// "- [Class(Category) selector :withArg ...]"
StringRef ClassNameStart(Name.getString().drop_front(2));
size_t FirstSpace = ClassNameStart.find(' ');
if (FirstSpace == StringRef::npos)
return;
StringRef SelectorStart(ClassNameStart.data() + FirstSpace + 1);
if (!SelectorStart.size())
return;
StringRef Selector(SelectorStart.data(), SelectorStart.size() - 1);
Unit.addNameAccelerator(Die, StringPool.getEntry(Selector), SkipPubSection);
// Add an entry for the class name that points to this
// method/class function.
StringRef ClassName(ClassNameStart.data(), FirstSpace);
Unit.addObjCAccelerator(Die, StringPool.getEntry(ClassName), SkipPubSection);
if (ClassName[ClassName.size() - 1] == ')') {
size_t OpenParens = ClassName.find('(');
if (OpenParens != StringRef::npos) {
StringRef ClassNameNoCategory(ClassName.data(), OpenParens);
Unit.addObjCAccelerator(Die, StringPool.getEntry(ClassNameNoCategory),
SkipPubSection);
std::string MethodNameNoCategory(Name.getString().data(), OpenParens + 2);
// FIXME: The missing space here may be a bug, but
// dsymutil-classic also does it this way.
MethodNameNoCategory.append(SelectorStart);
Unit.addNameAccelerator(Die, StringPool.getEntry(MethodNameNoCategory),
SkipPubSection);
}
}
}
static bool
shouldSkipAttribute(DWARFAbbreviationDeclaration::AttributeSpec AttrSpec,
uint16_t Tag, bool InDebugMap, bool SkipPC,
bool InFunctionScope) {
switch (AttrSpec.Attr) {
default:
return false;
case dwarf::DW_AT_low_pc:
case dwarf::DW_AT_high_pc:
case dwarf::DW_AT_ranges:
return SkipPC;
case dwarf::DW_AT_location:
case dwarf::DW_AT_frame_base:
// FIXME: for some reason dsymutil-classic keeps the location attributes
// when they are of block type (i.e. not location lists). This is totally
// wrong for globals where we will keep a wrong address. It is mostly
// harmless for locals, but there is no point in keeping these anyway when
// the function wasn't linked.
return (SkipPC || (!InFunctionScope && Tag == dwarf::DW_TAG_variable &&
!InDebugMap)) &&
!DWARFFormValue(AttrSpec.Form).isFormClass(DWARFFormValue::FC_Block);
}
}
DIE *DwarfLinker::DIECloner::cloneDIE(const DWARFDie &InputDIE,
const DebugMapObject &DMO,
CompileUnit &Unit,
OffsetsStringPool &StringPool,
int64_t PCOffset, uint32_t OutOffset,
unsigned Flags, DIE *Die) {
DWARFUnit &U = Unit.getOrigUnit();
unsigned Idx = U.getDIEIndex(InputDIE);
CompileUnit::DIEInfo &Info = Unit.getInfo(Idx);
// Should the DIE appear in the output?
if (!Unit.getInfo(Idx).Keep)
return nullptr;
uint32_t Offset = InputDIE.getOffset();
assert(!(Die && Info.Clone) && "Can't supply a DIE and a cloned DIE");
if (!Die) {
// The DIE might have been already created by a forward reference
// (see cloneDieReferenceAttribute()).
if (!Info.Clone)
Info.Clone = DIE::get(DIEAlloc, dwarf::Tag(InputDIE.getTag()));
Die = Info.Clone;
}
assert(Die->getTag() == InputDIE.getTag());
Die->setOffset(OutOffset);
if ((Unit.hasODR() || Unit.isClangModule()) && !Info.Incomplete &&
Die->getTag() != dwarf::DW_TAG_namespace && Info.Ctxt &&
Info.Ctxt != Unit.getInfo(Info.ParentIdx).Ctxt &&
!Info.Ctxt->getCanonicalDIEOffset()) {
// We are about to emit a DIE that is the root of its own valid
// DeclContext tree. Make the current offset the canonical offset
// for this context.
Info.Ctxt->setCanonicalDIEOffset(OutOffset + Unit.getStartOffset());
}
// Extract and clone every attribute.
DWARFDataExtractor Data = U.getDebugInfoExtractor();
// Point to the next DIE (generally there is always at least a NULL
// entry after the current one). If this is a lone
// DW_TAG_compile_unit without any children, point to the next unit.
uint32_t NextOffset = (Idx + 1 < U.getNumDIEs())
? U.getDIEAtIndex(Idx + 1).getOffset()
: U.getNextUnitOffset();
AttributesInfo AttrInfo;
// We could copy the data only if we need to apply a relocation to it. After
// testing, it seems there is no performance downside to doing the copy
// unconditionally, and it makes the code simpler.
SmallString<40> DIECopy(Data.getData().substr(Offset, NextOffset - Offset));
Data =
DWARFDataExtractor(DIECopy, Data.isLittleEndian(), Data.getAddressSize());
// Modify the copy with relocated addresses.
if (RelocMgr.applyValidRelocs(DIECopy, Offset, Data.isLittleEndian())) {
// If we applied relocations, we store the value of high_pc that was
// potentially stored in the input DIE. If high_pc is an address
// (Dwarf version == 2), then it might have been relocated to a
// totally unrelated value (because the end address in the object
// file might be start address of another function which got moved
// independently by the linker). The computation of the actual
// high_pc value is done in cloneAddressAttribute().
AttrInfo.OrigHighPc =
dwarf::toAddress(InputDIE.find(dwarf::DW_AT_high_pc), 0);
// Also store the low_pc. It might get relocated in an
// inline_subprogram that happens at the beginning of its
// inlining function.
AttrInfo.OrigLowPc = dwarf::toAddress(InputDIE.find(dwarf::DW_AT_low_pc),
std::numeric_limits<uint64_t>::max());
}
// Reset the Offset to 0 as we will be working on the local copy of
// the data.
Offset = 0;
const auto *Abbrev = InputDIE.getAbbreviationDeclarationPtr();
Offset += getULEB128Size(Abbrev->getCode());
// We are entering a subprogram. Get and propagate the PCOffset.
if (Die->getTag() == dwarf::DW_TAG_subprogram)
PCOffset = Info.AddrAdjust;
AttrInfo.PCOffset = PCOffset;
if (Abbrev->getTag() == dwarf::DW_TAG_subprogram) {
Flags |= TF_InFunctionScope;
if (!Info.InDebugMap && LLVM_LIKELY(!Options.Update))
Flags |= TF_SkipPC;
}
bool Copied = false;
for (const auto &AttrSpec : Abbrev->attributes()) {
if (LLVM_LIKELY(!Options.Update) &&
shouldSkipAttribute(AttrSpec, Die->getTag(), Info.InDebugMap,
Flags & TF_SkipPC, Flags & TF_InFunctionScope)) {
DWARFFormValue::skipValue(AttrSpec.Form, Data, &Offset,
U.getFormParams());
// FIXME: dsymutil-classic keeps the old abbreviation around
// even if it's not used. We can remove this (and the copyAbbrev
// helper) as soon as bit-for-bit compatibility is not a goal anymore.
if (!Copied) {
copyAbbrev(*InputDIE.getAbbreviationDeclarationPtr(), Unit.hasODR());
Copied = true;
}
continue;
}
DWARFFormValue Val(AttrSpec.Form);
uint32_t AttrSize = Offset;
Val.extractValue(Data, &Offset, U.getFormParams(), &U);
AttrSize = Offset - AttrSize;
OutOffset += cloneAttribute(*Die, InputDIE, DMO, Unit, StringPool, Val,
AttrSpec, AttrSize, AttrInfo);
}
// Look for accelerator entries.
uint16_t Tag = InputDIE.getTag();
// FIXME: This is slightly wrong. An inline_subroutine without a
// low_pc, but with AT_ranges might be interesting to get into the
// accelerator tables too. For now stick with dsymutil's behavior.
if ((Info.InDebugMap || AttrInfo.HasLowPc || AttrInfo.HasRanges) &&
Tag != dwarf::DW_TAG_compile_unit &&
getDIENames(InputDIE, AttrInfo, StringPool,
Tag != dwarf::DW_TAG_inlined_subroutine)) {
if (AttrInfo.MangledName && AttrInfo.MangledName != AttrInfo.Name)
Unit.addNameAccelerator(Die, AttrInfo.MangledName,
Tag == dwarf::DW_TAG_inlined_subroutine);
if (AttrInfo.Name) {
if (AttrInfo.NameWithoutTemplate)
Unit.addNameAccelerator(Die, AttrInfo.NameWithoutTemplate,
/* SkipPubSection */ true);
Unit.addNameAccelerator(Die, AttrInfo.Name,
Tag == dwarf::DW_TAG_inlined_subroutine);
}
if (AttrInfo.Name && isObjCSelector(AttrInfo.Name.getString()))
addObjCAccelerator(Unit, Die, AttrInfo.Name, StringPool,
/* SkipPubSection =*/true);
} else if (Tag == dwarf::DW_TAG_namespace) {
if (!AttrInfo.Name)
AttrInfo.Name = StringPool.getEntry("(anonymous namespace)");
Unit.addNamespaceAccelerator(Die, AttrInfo.Name);
} else if (isTypeTag(Tag) && !AttrInfo.IsDeclaration &&
getDIENames(InputDIE, AttrInfo, StringPool) && AttrInfo.Name &&
AttrInfo.Name.getString()[0]) {
uint32_t Hash = hashFullyQualifiedName(InputDIE, Unit, DMO);
uint64_t RuntimeLang =
dwarf::toUnsigned(InputDIE.find(dwarf::DW_AT_APPLE_runtime_class))
.getValueOr(0);
bool ObjCClassIsImplementation =
(RuntimeLang == dwarf::DW_LANG_ObjC ||
RuntimeLang == dwarf::DW_LANG_ObjC_plus_plus) &&
dwarf::toUnsigned(InputDIE.find(dwarf::DW_AT_APPLE_objc_complete_type))
.getValueOr(0);
Unit.addTypeAccelerator(Die, AttrInfo.Name, ObjCClassIsImplementation,
Hash);
}
// Determine whether there are any children that we want to keep.
bool HasChildren = false;
for (auto Child : InputDIE.children()) {
unsigned Idx = U.getDIEIndex(Child);
if (Unit.getInfo(Idx).Keep) {
HasChildren = true;
break;
}
}
DIEAbbrev NewAbbrev = Die->generateAbbrev();
if (HasChildren)
NewAbbrev.setChildrenFlag(dwarf::DW_CHILDREN_yes);
// Assign a permanent abbrev number
Linker.AssignAbbrev(NewAbbrev);
Die->setAbbrevNumber(NewAbbrev.getNumber());
// Add the size of the abbreviation number to the output offset.
OutOffset += getULEB128Size(Die->getAbbrevNumber());
if (!HasChildren) {
// Update our size.
Die->setSize(OutOffset - Die->getOffset());
return Die;
}
// Recursively clone children.
for (auto Child : InputDIE.children()) {
if (DIE *Clone = cloneDIE(Child, DMO, Unit, StringPool, PCOffset, OutOffset,
Flags)) {
Die->addChild(Clone);
OutOffset = Clone->getOffset() + Clone->getSize();
}
}
// Account for the end of children marker.
OutOffset += sizeof(int8_t);
// Update our size.
Die->setSize(OutOffset - Die->getOffset());
return Die;
}
/// Patch the input object file relevant debug_ranges entries
/// and emit them in the output file. Update the relevant attributes
/// to point at the new entries.
void DwarfLinker::patchRangesForUnit(const CompileUnit &Unit,
DWARFContext &OrigDwarf,
const DebugMapObject &DMO) const {
DWARFDebugRangeList RangeList;
const auto &FunctionRanges = Unit.getFunctionRanges();
unsigned AddressSize = Unit.getOrigUnit().getAddressByteSize();
DWARFDataExtractor RangeExtractor(OrigDwarf.getDWARFObj(),
OrigDwarf.getDWARFObj().getRangeSection(),
OrigDwarf.isLittleEndian(), AddressSize);
auto InvalidRange = FunctionRanges.end(), CurrRange = InvalidRange;
DWARFUnit &OrigUnit = Unit.getOrigUnit();
auto OrigUnitDie = OrigUnit.getUnitDIE(false);
uint64_t OrigLowPc =
dwarf::toAddress(OrigUnitDie.find(dwarf::DW_AT_low_pc), -1ULL);
// Ranges addresses are based on the unit's low_pc. Compute the
// offset we need to apply to adapt to the new unit's low_pc.
int64_t UnitPcOffset = 0;
if (OrigLowPc != -1ULL)
UnitPcOffset = int64_t(OrigLowPc) - Unit.getLowPc();
for (const auto &RangeAttribute : Unit.getRangesAttributes()) {
uint32_t Offset = RangeAttribute.get();
RangeAttribute.set(Streamer->getRangesSectionSize());
RangeList.extract(RangeExtractor, &Offset);
const auto &Entries = RangeList.getEntries();
if (!Entries.empty()) {
const DWARFDebugRangeList::RangeListEntry &First = Entries.front();
if (CurrRange == InvalidRange ||
First.StartAddress + OrigLowPc < CurrRange.start() ||
First.StartAddress + OrigLowPc >= CurrRange.stop()) {
CurrRange = FunctionRanges.find(First.StartAddress + OrigLowPc);
if (CurrRange == InvalidRange ||
CurrRange.start() > First.StartAddress + OrigLowPc) {
reportWarning("no mapping for range.", DMO);
continue;
}
}
}
Streamer->emitRangesEntries(UnitPcOffset, OrigLowPc, CurrRange, Entries,
AddressSize);
}
}
/// Generate the debug_aranges entries for \p Unit and if the
/// unit has a DW_AT_ranges attribute, also emit the debug_ranges
/// contribution for this attribute.
/// FIXME: this could actually be done right in patchRangesForUnit,
/// but for the sake of initial bit-for-bit compatibility with legacy
/// dsymutil, we have to do it in a delayed pass.
void DwarfLinker::generateUnitRanges(CompileUnit &Unit) const {
auto Attr = Unit.getUnitRangesAttribute();
if (Attr)
Attr->set(Streamer->getRangesSectionSize());
Streamer->emitUnitRangesEntries(Unit, static_cast<bool>(Attr));
}
/// Insert the new line info sequence \p Seq into the current
/// set of already linked line info \p Rows.
static void insertLineSequence(std::vector<DWARFDebugLine::Row> &Seq,
std::vector<DWARFDebugLine::Row> &Rows) {
if (Seq.empty())
return;
if (!Rows.empty() && Rows.back().Address < Seq.front().Address) {
Rows.insert(Rows.end(), Seq.begin(), Seq.end());
Seq.clear();
return;
}
auto InsertPoint = std::lower_bound(
Rows.begin(), Rows.end(), Seq.front(),
[](const DWARFDebugLine::Row &LHS, const DWARFDebugLine::Row &RHS) {
return LHS.Address < RHS.Address;
});
// FIXME: this only removes the unneeded end_sequence if the
// sequences have been inserted in order. Using a global sort like
// described in patchLineTableForUnit() and delaying the end_sequene
// elimination to emitLineTableForUnit() we can get rid of all of them.
if (InsertPoint != Rows.end() &&
InsertPoint->Address == Seq.front().Address && InsertPoint->EndSequence) {
*InsertPoint = Seq.front();
Rows.insert(InsertPoint + 1, Seq.begin() + 1, Seq.end());
} else {
Rows.insert(InsertPoint, Seq.begin(), Seq.end());
}
Seq.clear();
}
static void patchStmtList(DIE &Die, DIEInteger Offset) {
for (auto &V : Die.values())
if (V.getAttribute() == dwarf::DW_AT_stmt_list) {
V = DIEValue(V.getAttribute(), V.getForm(), Offset);
return;
}
llvm_unreachable("Didn't find DW_AT_stmt_list in cloned DIE!");
}
/// Extract the line table for \p Unit from \p OrigDwarf, and
/// recreate a relocated version of these for the address ranges that
/// are present in the binary.
void DwarfLinker::patchLineTableForUnit(CompileUnit &Unit,
DWARFContext &OrigDwarf,
RangesTy &Ranges,
const DebugMapObject &DMO) {
DWARFDie CUDie = Unit.getOrigUnit().getUnitDIE();
auto StmtList = dwarf::toSectionOffset(CUDie.find(dwarf::DW_AT_stmt_list));
if (!StmtList)
return;
// Update the cloned DW_AT_stmt_list with the correct debug_line offset.
if (auto *OutputDIE = Unit.getOutputUnitDIE())
patchStmtList(*OutputDIE, DIEInteger(Streamer->getLineSectionSize()));
// Parse the original line info for the unit.
DWARFDebugLine::LineTable LineTable;
uint32_t StmtOffset = *StmtList;
DWARFDataExtractor LineExtractor(
OrigDwarf.getDWARFObj(), OrigDwarf.getDWARFObj().getLineSection(),
OrigDwarf.isLittleEndian(), Unit.getOrigUnit().getAddressByteSize());
Error Err = LineTable.parse(LineExtractor, &StmtOffset, OrigDwarf,
&Unit.getOrigUnit());
DWARFDebugLine::warnForError(std::move(Err));
// This vector is the output line table.
std::vector<DWARFDebugLine::Row> NewRows;
NewRows.reserve(LineTable.Rows.size());
// Current sequence of rows being extracted, before being inserted
// in NewRows.
std::vector<DWARFDebugLine::Row> Seq;
const auto &FunctionRanges = Unit.getFunctionRanges();
auto InvalidRange = FunctionRanges.end(), CurrRange = InvalidRange;
// FIXME: This logic is meant to generate exactly the same output as
// Darwin's classic dsymutil. There is a nicer way to implement this
// by simply putting all the relocated line info in NewRows and simply
// sorting NewRows before passing it to emitLineTableForUnit. This
// should be correct as sequences for a function should stay
// together in the sorted output. There are a few corner cases that
// look suspicious though, and that required to implement the logic
// this way. Revisit that once initial validation is finished.
// Iterate over the object file line info and extract the sequences
// that correspond to linked functions.
for (auto &Row : LineTable.Rows) {
// Check whether we stepped out of the range. The range is
// half-open, but consider accept the end address of the range if
// it is marked as end_sequence in the input (because in that
// case, the relocation offset is accurate and that entry won't
// serve as the start of another function).
if (CurrRange == InvalidRange || Row.Address < CurrRange.start() ||
Row.Address > CurrRange.stop() ||
(Row.Address == CurrRange.stop() && !Row.EndSequence)) {
// We just stepped out of a known range. Insert a end_sequence
// corresponding to the end of the range.
uint64_t StopAddress = CurrRange != InvalidRange
? CurrRange.stop() + CurrRange.value()
: -1ULL;
CurrRange = FunctionRanges.find(Row.Address);
bool CurrRangeValid =
CurrRange != InvalidRange && CurrRange.start() <= Row.Address;
if (!CurrRangeValid) {
CurrRange = InvalidRange;
if (StopAddress != -1ULL) {
// Try harder by looking in the DebugMapObject function
// ranges map. There are corner cases where this finds a
// valid entry. It's unclear if this is right or wrong, but
// for now do as dsymutil.
// FIXME: Understand exactly what cases this addresses and
// potentially remove it along with the Ranges map.
auto Range = Ranges.lower_bound(Row.Address);
if (Range != Ranges.begin() && Range != Ranges.end())
--Range;
if (Range != Ranges.end() && Range->first <= Row.Address &&
Range->second.HighPC >= Row.Address) {
StopAddress = Row.Address + Range->second.Offset;
}
}
}
if (StopAddress != -1ULL && !Seq.empty()) {
// Insert end sequence row with the computed end address, but
// the same line as the previous one.
auto NextLine = Seq.back();
NextLine.Address = StopAddress;
NextLine.EndSequence = 1;
NextLine.PrologueEnd = 0;
NextLine.BasicBlock = 0;
NextLine.EpilogueBegin = 0;
Seq.push_back(NextLine);
insertLineSequence(Seq, NewRows);
}
if (!CurrRangeValid)
continue;
}
// Ignore empty sequences.
if (Row.EndSequence && Seq.empty())
continue;
// Relocate row address and add it to the current sequence.
Row.Address += CurrRange.value();
Seq.emplace_back(Row);
if (Row.EndSequence)
insertLineSequence(Seq, NewRows);
}
// Finished extracting, now emit the line tables.
// FIXME: LLVM hard-codes its prologue values. We just copy the
// prologue over and that works because we act as both producer and
// consumer. It would be nicer to have a real configurable line
// table emitter.
if (LineTable.Prologue.getVersion() < 2 ||
LineTable.Prologue.getVersion() > 5 ||
LineTable.Prologue.DefaultIsStmt != DWARF2_LINE_DEFAULT_IS_STMT ||
LineTable.Prologue.OpcodeBase > 13)
reportWarning("line table parameters mismatch. Cannot emit.", DMO);
else {
uint32_t PrologueEnd = *StmtList + 10 + LineTable.Prologue.PrologueLength;
// DWARF v5 has an extra 2 bytes of information before the header_length
// field.
if (LineTable.Prologue.getVersion() == 5)
PrologueEnd += 2;
StringRef LineData = OrigDwarf.getDWARFObj().getLineSection().Data;
MCDwarfLineTableParams Params;
Params.DWARF2LineOpcodeBase = LineTable.Prologue.OpcodeBase;
Params.DWARF2LineBase = LineTable.Prologue.LineBase;
Params.DWARF2LineRange = LineTable.Prologue.LineRange;
Streamer->emitLineTableForUnit(Params,
LineData.slice(*StmtList + 4, PrologueEnd),
LineTable.Prologue.MinInstLength, NewRows,
Unit.getOrigUnit().getAddressByteSize());
}
}
void DwarfLinker::emitAcceleratorEntriesForUnit(CompileUnit &Unit) {
// Add namespaces.
for (const auto &Namespace : Unit.getNamespaces())
AppleNamespaces.addName(Namespace.Name,
Namespace.Die->getOffset() + Unit.getStartOffset());
/// Add names.
if (!Options.Minimize)
Streamer->emitPubNamesForUnit(Unit);
for (const auto &Pubname : Unit.getPubnames())
AppleNames.addName(Pubname.Name,
Pubname.Die->getOffset() + Unit.getStartOffset());
/// Add types.
if (!Options.Minimize)
Streamer->emitPubTypesForUnit(Unit);
for (const auto &Pubtype : Unit.getPubtypes())
AppleTypes.addName(
Pubtype.Name, Pubtype.Die->getOffset() + Unit.getStartOffset(),
Pubtype.Die->getTag(),
Pubtype.ObjcClassImplementation ? dwarf::DW_FLAG_type_implementation
: 0,
Pubtype.QualifiedNameHash);
/// Add ObjC names.
for (const auto &ObjC : Unit.getObjC())
AppleObjc.addName(ObjC.Name, ObjC.Die->getOffset() + Unit.getStartOffset());
}
/// Read the frame info stored in the object, and emit the
/// patched frame descriptions for the linked binary.
///
/// This is actually pretty easy as the data of the CIEs and FDEs can
/// be considered as black boxes and moved as is. The only thing to do
/// is to patch the addresses in the headers.
void DwarfLinker::patchFrameInfoForObject(const DebugMapObject &DMO,
RangesTy &Ranges,
DWARFContext &OrigDwarf,
unsigned AddrSize) {
StringRef FrameData = OrigDwarf.getDWARFObj().getDebugFrameSection();
if (FrameData.empty())
return;
DataExtractor Data(FrameData, OrigDwarf.isLittleEndian(), 0);
uint32_t InputOffset = 0;
// Store the data of the CIEs defined in this object, keyed by their
// offsets.
DenseMap<uint32_t, StringRef> LocalCIES;
while (Data.isValidOffset(InputOffset)) {
uint32_t EntryOffset = InputOffset;
uint32_t InitialLength = Data.getU32(&InputOffset);
if (InitialLength == 0xFFFFFFFF)
return reportWarning("Dwarf64 bits no supported", DMO);
uint32_t CIEId = Data.getU32(&InputOffset);
if (CIEId == 0xFFFFFFFF) {
// This is a CIE, store it.
StringRef CIEData = FrameData.substr(EntryOffset, InitialLength + 4);
LocalCIES[EntryOffset] = CIEData;
// The -4 is to account for the CIEId we just read.
InputOffset += InitialLength - 4;
continue;
}
uint32_t Loc = Data.getUnsigned(&InputOffset, AddrSize);
// Some compilers seem to emit frame info that doesn't start at
// the function entry point, thus we can't just lookup the address
// in the debug map. Use the linker's range map to see if the FDE
// describes something that we can relocate.
auto Range = Ranges.upper_bound(Loc);
if (Range != Ranges.begin())
--Range;
if (Range == Ranges.end() || Range->first > Loc ||
Range->second.HighPC <= Loc) {
// The +4 is to account for the size of the InitialLength field itself.
InputOffset = EntryOffset + InitialLength + 4;
continue;
}
// This is an FDE, and we have a mapping.
// Have we already emitted a corresponding CIE?
StringRef CIEData = LocalCIES[CIEId];
if (CIEData.empty())
return reportWarning("Inconsistent debug_frame content. Dropping.", DMO);
// Look if we already emitted a CIE that corresponds to the
// referenced one (the CIE data is the key of that lookup).
auto IteratorInserted = EmittedCIEs.insert(
std::make_pair(CIEData, Streamer->getFrameSectionSize()));
// If there is no CIE yet for this ID, emit it.
if (IteratorInserted.second ||
// FIXME: dsymutil-classic only caches the last used CIE for
// reuse. Mimic that behavior for now. Just removing that
// second half of the condition and the LastCIEOffset variable
// makes the code DTRT.
LastCIEOffset != IteratorInserted.first->getValue()) {
LastCIEOffset = Streamer->getFrameSectionSize();
IteratorInserted.first->getValue() = LastCIEOffset;
Streamer->emitCIE(CIEData);
}
// Emit the FDE with updated address and CIE pointer.
// (4 + AddrSize) is the size of the CIEId + initial_location
// fields that will get reconstructed by emitFDE().
unsigned FDERemainingBytes = InitialLength - (4 + AddrSize);
Streamer->emitFDE(IteratorInserted.first->getValue(), AddrSize,
Loc + Range->second.Offset,
FrameData.substr(InputOffset, FDERemainingBytes));
InputOffset += FDERemainingBytes;
}
}
void DwarfLinker::DIECloner::copyAbbrev(
const DWARFAbbreviationDeclaration &Abbrev, bool hasODR) {
DIEAbbrev Copy(dwarf::Tag(Abbrev.getTag()),
dwarf::Form(Abbrev.hasChildren()));
for (const auto &Attr : Abbrev.attributes()) {
uint16_t Form = Attr.Form;
if (hasODR && isODRAttribute(Attr.Attr))
Form = dwarf::DW_FORM_ref_addr;
Copy.AddAttribute(dwarf::Attribute(Attr.Attr), dwarf::Form(Form));
}
Linker.AssignAbbrev(Copy);
}
uint32_t DwarfLinker::DIECloner::hashFullyQualifiedName(
DWARFDie DIE, CompileUnit &U, const DebugMapObject &DMO, int RecurseDepth) {
const char *Name = nullptr;
DWARFUnit *OrigUnit = &U.getOrigUnit();
CompileUnit *CU = &U;
Optional<DWARFFormValue> Ref;
while (1) {
if (const char *CurrentName = DIE.getName(DINameKind::ShortName))
Name = CurrentName;
if (!(Ref = DIE.find(dwarf::DW_AT_specification)) &&
!(Ref = DIE.find(dwarf::DW_AT_abstract_origin)))
break;
if (!Ref->isFormClass(DWARFFormValue::FC_Reference))
break;
CompileUnit *RefCU;
if (auto RefDIE = resolveDIEReference(Linker, DMO, CompileUnits, *Ref,
U.getOrigUnit(), DIE, RefCU)) {
CU = RefCU;
OrigUnit = &RefCU->getOrigUnit();
DIE = RefDIE;
}
}
unsigned Idx = OrigUnit->getDIEIndex(DIE);
if (!Name && DIE.getTag() == dwarf::DW_TAG_namespace)
Name = "(anonymous namespace)";
if (CU->getInfo(Idx).ParentIdx == 0 ||
// FIXME: dsymutil-classic compatibility. Ignore modules.
CU->getOrigUnit().getDIEAtIndex(CU->getInfo(Idx).ParentIdx).getTag() ==
dwarf::DW_TAG_module)
return djbHash(Name ? Name : "", djbHash(RecurseDepth ? "" : "::"));
DWARFDie Die = OrigUnit->getDIEAtIndex(CU->getInfo(Idx).ParentIdx);
return djbHash(
(Name ? Name : ""),
djbHash((Name ? "::" : ""),
hashFullyQualifiedName(Die, *CU, DMO, ++RecurseDepth)));
}
static uint64_t getDwoId(const DWARFDie &CUDie, const DWARFUnit &Unit) {
auto DwoId = dwarf::toUnsigned(
CUDie.find({dwarf::DW_AT_dwo_id, dwarf::DW_AT_GNU_dwo_id}));
if (DwoId)
return *DwoId;
return 0;
}
bool DwarfLinker::registerModuleReference(
const DWARFDie &CUDie, const DWARFUnit &Unit, DebugMap &ModuleMap,
const DebugMapObject &DMO, RangesTy &Ranges, OffsetsStringPool &StringPool,
UniquingStringPool &UniquingStringPool, DeclContextTree &ODRContexts,
unsigned &UnitID, unsigned Indent) {
std::string PCMfile = dwarf::toString(
CUDie.find({dwarf::DW_AT_dwo_name, dwarf::DW_AT_GNU_dwo_name}), "");
if (PCMfile.empty())
return false;
// Clang module DWARF skeleton CUs abuse this for the path to the module.
std::string PCMpath = dwarf::toString(CUDie.find(dwarf::DW_AT_comp_dir), "");
uint64_t DwoId = getDwoId(CUDie, Unit);
std::string Name = dwarf::toString(CUDie.find(dwarf::DW_AT_name), "");
if (Name.empty()) {
reportWarning("Anonymous module skeleton CU for " + PCMfile, DMO);
return true;
}
if (Options.Verbose) {
outs().indent(Indent);
outs() << "Found clang module reference " << PCMfile;
}
auto Cached = ClangModules.find(PCMfile);
if (Cached != ClangModules.end()) {
// FIXME: Until PR27449 (https://llvm.org/bugs/show_bug.cgi?id=27449) is
// fixed in clang, only warn about DWO_id mismatches in verbose mode.
// ASTFileSignatures will change randomly when a module is rebuilt.
if (Options.Verbose && (Cached->second != DwoId))
reportWarning(Twine("hash mismatch: this object file was built against a "
"different version of the module ") +
PCMfile,
DMO);
if (Options.Verbose)
outs() << " [cached].\n";
return true;
}
if (Options.Verbose)
outs() << " ...\n";
// Cyclic dependencies are disallowed by Clang, but we still
// shouldn't run into an infinite loop, so mark it as processed now.
ClangModules.insert({PCMfile, DwoId});
if (Error E = loadClangModule(PCMfile, PCMpath, Name, DwoId, ModuleMap, DMO,
Ranges, StringPool, UniquingStringPool,
ODRContexts, UnitID, Indent + 2)) {
consumeError(std::move(E));
return false;
}
return true;
}
ErrorOr<const object::ObjectFile &>
DwarfLinker::loadObject(BinaryHolder &BinaryHolder, const DebugMapObject &Obj,
const DebugMap &Map) {
auto ErrOrObjs =
BinaryHolder.GetObjectFiles(Obj.getObjectFilename(), Obj.getTimestamp());
if (std::error_code EC = ErrOrObjs.getError()) {
reportWarning(Twine(Obj.getObjectFilename()) + ": " + EC.message(), Obj);
return EC;
}
auto ErrOrObj = BinaryHolder.Get(Map.getTriple());
if (std::error_code EC = ErrOrObj.getError())
reportWarning(Twine(Obj.getObjectFilename()) + ": " + EC.message(), Obj);
return ErrOrObj;
}
Error DwarfLinker::loadClangModule(StringRef Filename, StringRef ModulePath,
StringRef ModuleName, uint64_t DwoId,
DebugMap &ModuleMap,
const DebugMapObject &DMO, RangesTy &Ranges,
OffsetsStringPool &StringPool,
UniquingStringPool &UniquingStringPool,
DeclContextTree &ODRContexts,
unsigned &UnitID, unsigned Indent) {
SmallString<80> Path(Options.PrependPath);
if (sys::path::is_relative(Filename))
sys::path::append(Path, ModulePath, Filename);
else
sys::path::append(Path, Filename);
BinaryHolder ObjHolder(Options.Verbose);
auto &Obj = ModuleMap.addDebugMapObject(
Path, sys::TimePoint<std::chrono::seconds>(), MachO::N_OSO);
auto ErrOrObj = loadObject(ObjHolder, Obj, ModuleMap);
if (!ErrOrObj) {
// Try and emit more helpful warnings by applying some heuristics.
StringRef ObjFile = DMO.getObjectFilename();
bool isClangModule = sys::path::extension(Filename).equals(".pcm");
bool isArchive = ObjFile.endswith(")");
if (isClangModule) {
StringRef ModuleCacheDir = sys::path::parent_path(Path);
if (sys::fs::exists(ModuleCacheDir)) {
// If the module's parent directory exists, we assume that the module
// cache has expired and was pruned by clang. A more adventurous
// dsymutil would invoke clang to rebuild the module now.
if (!ModuleCacheHintDisplayed) {
WithColor::note() << "The clang module cache may have expired since "
"this object file was built. Rebuilding the "
"object file will rebuild the module cache.\n";
ModuleCacheHintDisplayed = true;
}
} else if (isArchive) {
// If the module cache directory doesn't exist at all and the object
// file is inside a static library, we assume that the static library
// was built on a different machine. We don't want to discourage module
// debugging for convenience libraries within a project though.
if (!ArchiveHintDisplayed) {
WithColor::note()
<< "Linking a static library that was built with "
"-gmodules, but the module cache was not found. "
"Redistributable static libraries should never be "
"built with module debugging enabled. The debug "
"experience will be degraded due to incomplete "
"debug information.\n";
ArchiveHintDisplayed = true;
}
}
}
return Error::success();
}
std::unique_ptr<CompileUnit> Unit;
// Setup access to the debug info.
auto DwarfContext = DWARFContext::create(*ErrOrObj);
RelocationManager RelocMgr(*this);
for (const auto &CU : DwarfContext->compile_units()) {
maybeUpdateMaxDwarfVersion(CU->getVersion());
// Recursively get all modules imported by this one.
auto CUDie = CU->getUnitDIE(false);
if (!CUDie)
continue;
if (!registerModuleReference(CUDie, *CU, ModuleMap, DMO, Ranges, StringPool,
UniquingStringPool, ODRContexts, UnitID,
Indent)) {
if (Unit) {
std::string Err =
(Filename +
": Clang modules are expected to have exactly 1 compile unit.\n")
.str();
error(Err);
return make_error<StringError>(Err, inconvertibleErrorCode());
}
// FIXME: Until PR27449 (https://llvm.org/bugs/show_bug.cgi?id=27449) is
// fixed in clang, only warn about DWO_id mismatches in verbose mode.
// ASTFileSignatures will change randomly when a module is rebuilt.
uint64_t PCMDwoId = getDwoId(CUDie, *CU);
if (PCMDwoId != DwoId) {
if (Options.Verbose)
reportWarning(
Twine("hash mismatch: this object file was built against a "
"different version of the module ") +
Filename,
DMO);
// Update the cache entry with the DwoId of the module loaded from disk.
ClangModules[Filename] = PCMDwoId;
}
// Add this module.
Unit = llvm::make_unique<CompileUnit>(*CU, UnitID++, !Options.NoODR,
ModuleName);
Unit->setHasInterestingContent();
analyzeContextInfo(CUDie, 0, *Unit, &ODRContexts.getRoot(),
UniquingStringPool, ODRContexts);
// Keep everything.
Unit->markEverythingAsKept();
}
}
if (!Unit->getOrigUnit().getUnitDIE().hasChildren())
return Error::success();
if (Options.Verbose) {
outs().indent(Indent);
outs() << "cloning .debug_info from " << Filename << "\n";
}
std::vector<std::unique_ptr<CompileUnit>> CompileUnits;
CompileUnits.push_back(std::move(Unit));
DIECloner(*this, RelocMgr, DIEAlloc, CompileUnits, Options)
.cloneAllCompileUnits(*DwarfContext, DMO, Ranges, StringPool);
return Error::success();
}
void DwarfLinker::DIECloner::cloneAllCompileUnits(
DWARFContext &DwarfContext, const DebugMapObject &DMO, RangesTy &Ranges,
OffsetsStringPool &StringPool) {
if (!Linker.Streamer)
return;
for (auto &CurrentUnit : CompileUnits) {
auto InputDIE = CurrentUnit->getOrigUnit().getUnitDIE();
CurrentUnit->setStartOffset(Linker.OutputDebugInfoSize);
if (!InputDIE) {
Linker.OutputDebugInfoSize = CurrentUnit->computeNextUnitOffset();
continue;
}
if (CurrentUnit->getInfo(0).Keep) {
// Clone the InputDIE into your Unit DIE in our compile unit since it
// already has a DIE inside of it.
CurrentUnit->createOutputDIE();
cloneDIE(InputDIE, DMO, *CurrentUnit, StringPool, 0 /* PC offset */,
11 /* Unit Header size */, 0, CurrentUnit->getOutputUnitDIE());
}
Linker.OutputDebugInfoSize = CurrentUnit->computeNextUnitOffset();
if (Linker.Options.NoOutput)
continue;
if (LLVM_LIKELY(!Linker.Options.Update)) {
// FIXME: for compatibility with the classic dsymutil, we emit an empty
// line table for the unit, even if the unit doesn't actually exist in
// the DIE tree.
Linker.patchLineTableForUnit(*CurrentUnit, DwarfContext, Ranges, DMO);
Linker.emitAcceleratorEntriesForUnit(*CurrentUnit);
Linker.patchRangesForUnit(*CurrentUnit, DwarfContext, DMO);
Linker.Streamer->emitLocationsForUnit(*CurrentUnit, DwarfContext);
} else {
Linker.emitAcceleratorEntriesForUnit(*CurrentUnit);
}
}
if (Linker.Options.NoOutput)
return;
// Emit all the compile unit's debug information.
for (auto &CurrentUnit : CompileUnits) {
if (LLVM_LIKELY(!Linker.Options.Update))
Linker.generateUnitRanges(*CurrentUnit);
CurrentUnit->fixupForwardReferences();
Linker.Streamer->emitCompileUnitHeader(*CurrentUnit);
if (!CurrentUnit->getOutputUnitDIE())
continue;
Linker.Streamer->emitDIE(*CurrentUnit->getOutputUnitDIE());
}
}
bool DwarfLinker::emitPaperTrailWarnings(const DebugMapObject &DMO,
const DebugMap &Map,
OffsetsStringPool &StringPool) {
if (DMO.getWarnings().empty() || !DMO.empty())
return false;
Streamer->switchToDebugInfoSection(/* Version */ 2);
DIE *CUDie = DIE::get(DIEAlloc, dwarf::DW_TAG_compile_unit);
CUDie->setOffset(11);
StringRef Producer = StringPool.internString("dsymutil");
StringRef File = StringPool.internString(DMO.getObjectFilename());
CUDie->addValue(DIEAlloc, dwarf::DW_AT_producer, dwarf::DW_FORM_strp,
DIEInteger(StringPool.getStringOffset(Producer)));
DIEBlock *String = new (DIEAlloc) DIEBlock();
DIEBlocks.push_back(String);
for (auto &C : File)
String->addValue(DIEAlloc, dwarf::Attribute(0), dwarf::DW_FORM_data1,
DIEInteger(C));
String->addValue(DIEAlloc, dwarf::Attribute(0), dwarf::DW_FORM_data1,
DIEInteger(0));
CUDie->addValue(DIEAlloc, dwarf::DW_AT_name, dwarf::DW_FORM_string, String);
for (const auto &Warning : DMO.getWarnings()) {
DIE &ConstDie = CUDie->addChild(DIE::get(DIEAlloc, dwarf::DW_TAG_constant));
ConstDie.addValue(
DIEAlloc, dwarf::DW_AT_name, dwarf::DW_FORM_strp,
DIEInteger(StringPool.getStringOffset("dsymutil_warning")));
ConstDie.addValue(DIEAlloc, dwarf::DW_AT_artificial, dwarf::DW_FORM_flag,
DIEInteger(1));
ConstDie.addValue(DIEAlloc, dwarf::DW_AT_const_value, dwarf::DW_FORM_strp,
DIEInteger(StringPool.getStringOffset(Warning)));
}
unsigned Size = 4 /* FORM_strp */ + File.size() + 1 +
DMO.getWarnings().size() * (4 + 1 + 4) +
1 /* End of children */;
DIEAbbrev Abbrev = CUDie->generateAbbrev();
AssignAbbrev(Abbrev);
CUDie->setAbbrevNumber(Abbrev.getNumber());
Size += getULEB128Size(Abbrev.getNumber());
// Abbreviation ordering needed for classic compatibility.
for (auto &Child : CUDie->children()) {
Abbrev = Child.generateAbbrev();
AssignAbbrev(Abbrev);
Child.setAbbrevNumber(Abbrev.getNumber());
Size += getULEB128Size(Abbrev.getNumber());
}
CUDie->setSize(Size);
auto &Asm = Streamer->getAsmPrinter();
Asm.emitInt32(11 + CUDie->getSize() - 4);
Asm.emitInt16(2);
Asm.emitInt32(0);
Asm.emitInt8(Map.getTriple().isArch64Bit() ? 8 : 4);
Streamer->emitDIE(*CUDie);
OutputDebugInfoSize += 11 /* Header */ + Size;
return true;
}
bool DwarfLinker::link(const DebugMap &Map) {
if (!createStreamer(Map.getTriple(), OutFile))
return false;
// Size of the DIEs (and headers) generated for the linked output.
OutputDebugInfoSize = 0;
// A unique ID that identifies each compile unit.
unsigned UnitID = 0;
DebugMap ModuleMap(Map.getTriple(), Map.getBinaryPath());
// First populate the data structure we need for each iteration of the
// parallel loop.
unsigned NumObjects = Map.getNumberOfObjects();
std::vector<LinkContext> ObjectContexts;
ObjectContexts.reserve(NumObjects);
for (const auto &Obj : Map.objects())
ObjectContexts.emplace_back(Map, *this, *Obj.get(), Options.Verbose);
// This Dwarf string pool which is only used for uniquing. This one should
// never be used for offsets as its not thread-safe or predictable.
UniquingStringPool UniquingStringPool;
// This Dwarf string pool which is used for emission. It must be used
// serially as the order of calling getStringOffset matters for
// reproducibility.
OffsetsStringPool OffsetsStringPool;
// ODR Contexts for the link.
DeclContextTree ODRContexts;
for (LinkContext &LinkContext : ObjectContexts) {
if (Options.Verbose)
outs() << "DEBUG MAP OBJECT: " << LinkContext.DMO.getObjectFilename()
<< "\n";
// N_AST objects (swiftmodule files) should get dumped directly into the
// appropriate DWARF section.
if (LinkContext.DMO.getType() == MachO::N_AST) {
StringRef File = LinkContext.DMO.getObjectFilename();
auto ErrorOrMem = MemoryBuffer::getFile(File);
if (!ErrorOrMem) {
warn("Could not open '" + File + "'\n");
continue;
}
sys::fs::file_status Stat;
if (auto Err = sys::fs::status(File, Stat)) {
warn(Err.message());
continue;
}
if (!Options.NoTimestamp &&
Stat.getLastModificationTime() !=
sys::TimePoint<>(LinkContext.DMO.getTimestamp())) {
// Not using the helper here as we can easily stream TimePoint<>.
WithColor::warning()
<< "Timestamp mismatch for " << File << ": "
<< Stat.getLastModificationTime() << " and "
<< sys::TimePoint<>(LinkContext.DMO.getTimestamp()) << "\n";
continue;
}
// Copy the module into the .swift_ast section.
if (!Options.NoOutput)
Streamer->emitSwiftAST((*ErrorOrMem)->getBuffer());
continue;
}
if (emitPaperTrailWarnings(LinkContext.DMO, Map, OffsetsStringPool))
continue;
if (!LinkContext.ObjectFile)
continue;
// Look for relocations that correspond to debug map entries.
if (LLVM_LIKELY(!Options.Update) &&
!LinkContext.RelocMgr.findValidRelocsInDebugInfo(
*LinkContext.ObjectFile, LinkContext.DMO)) {
if (Options.Verbose)
outs() << "No valid relocations found. Skipping.\n";
// Clear this ObjFile entry as a signal to other loops that we should not
// process this iteration.
LinkContext.ObjectFile = nullptr;
continue;
}
// Setup access to the debug info.
if (!LinkContext.DwarfContext)
continue;
startDebugObject(LinkContext);
// In a first phase, just read in the debug info and load all clang modules.
LinkContext.CompileUnits.reserve(
LinkContext.DwarfContext->getNumCompileUnits());
for (const auto &CU : LinkContext.DwarfContext->compile_units()) {
auto CUDie = CU->getUnitDIE(false);
if (Options.Verbose) {
outs() << "Input compilation unit:";
DIDumpOptions DumpOpts;
DumpOpts.RecurseDepth = 0;
DumpOpts.Verbose = Options.Verbose;
CUDie.dump(outs(), 0, DumpOpts);
}
if (!CUDie || LLVM_UNLIKELY(Options.Update) ||
!registerModuleReference(CUDie, *CU, ModuleMap, LinkContext.DMO,
LinkContext.Ranges, OffsetsStringPool,
UniquingStringPool, ODRContexts, UnitID)) {
LinkContext.CompileUnits.push_back(llvm::make_unique<CompileUnit>(
*CU, UnitID++, !Options.NoODR && !Options.Update, ""));
maybeUpdateMaxDwarfVersion(CU->getVersion());
}
}
}
// If we haven't seen any CUs, pick an arbitrary valid Dwarf version anyway,
// to be able to emit papertrail warnings.
if (MaxDwarfVersion == 0)
MaxDwarfVersion = 3;
// These variables manage the list of processed object files.
// The mutex and condition variable are to ensure that this is thread safe.
std::mutex ProcessedFilesMutex;
std::condition_variable ProcessedFilesConditionVariable;
BitVector ProcessedFiles(NumObjects, false);
// Now do analyzeContextInfo in parallel as it is particularly expensive.
auto AnalyzeLambda = [&]() {
for (unsigned i = 0, e = NumObjects; i != e; ++i) {
auto &LinkContext = ObjectContexts[i];
if (!LinkContext.ObjectFile) {
std::unique_lock<std::mutex> LockGuard(ProcessedFilesMutex);
ProcessedFiles.set(i);
ProcessedFilesConditionVariable.notify_one();
continue;
}
// Now build the DIE parent links that we will use during the next phase.
for (auto &CurrentUnit : LinkContext.CompileUnits) {
auto CUDie = CurrentUnit->getOrigUnit().getUnitDIE();
if (!CUDie)
continue;
analyzeContextInfo(CurrentUnit->getOrigUnit().getUnitDIE(), 0,
*CurrentUnit, &ODRContexts.getRoot(),
UniquingStringPool, ODRContexts);
}
std::unique_lock<std::mutex> LockGuard(ProcessedFilesMutex);
ProcessedFiles.set(i);
ProcessedFilesConditionVariable.notify_one();
}
};
// And then the remaining work in serial again.
// Note, although this loop runs in serial, it can run in parallel with
// the analyzeContextInfo loop so long as we process files with indices >=
// than those processed by analyzeContextInfo.
auto CloneLambda = [&]() {
for (unsigned i = 0, e = NumObjects; i != e; ++i) {
{
std::unique_lock<std::mutex> LockGuard(ProcessedFilesMutex);
if (!ProcessedFiles[i]) {
ProcessedFilesConditionVariable.wait(
LockGuard, [&]() { return ProcessedFiles[i]; });
}
}
auto &LinkContext = ObjectContexts[i];
if (!LinkContext.ObjectFile)
continue;
// Then mark all the DIEs that need to be present in the linked output
// and collect some information about them.
// Note that this loop can not be merged with the previous one because
// cross-cu references require the ParentIdx to be setup for every CU in
// the object file before calling this.
if (LLVM_UNLIKELY(Options.Update)) {
for (auto &CurrentUnit : LinkContext.CompileUnits)
CurrentUnit->markEverythingAsKept();
Streamer->copyInvariantDebugSection(*LinkContext.ObjectFile, Options);
} else {
for (auto &CurrentUnit : LinkContext.CompileUnits)
lookForDIEsToKeep(LinkContext.RelocMgr, LinkContext.Ranges,
LinkContext.CompileUnits,
CurrentUnit->getOrigUnit().getUnitDIE(),
LinkContext.DMO, *CurrentUnit, 0);
}
// The calls to applyValidRelocs inside cloneDIE will walk the reloc
// array again (in the same way findValidRelocsInDebugInfo() did). We
// need to reset the NextValidReloc index to the beginning.
LinkContext.RelocMgr.resetValidRelocs();
if (LinkContext.RelocMgr.hasValidRelocs() ||
LLVM_UNLIKELY(Options.Update))
DIECloner(*this, LinkContext.RelocMgr, DIEAlloc,
LinkContext.CompileUnits, Options)
.cloneAllCompileUnits(*LinkContext.DwarfContext, LinkContext.DMO,
LinkContext.Ranges, OffsetsStringPool);
if (!Options.NoOutput && !LinkContext.CompileUnits.empty() &&
LLVM_LIKELY(!Options.Update))
patchFrameInfoForObject(
LinkContext.DMO, LinkContext.Ranges, *LinkContext.DwarfContext,
LinkContext.CompileUnits[0]->getOrigUnit().getAddressByteSize());
// Clean-up before starting working on the next object.
endDebugObject(LinkContext);
}
// Emit everything that's global.
if (!Options.NoOutput) {
Streamer->emitAbbrevs(Abbreviations, MaxDwarfVersion);
Streamer->emitStrings(OffsetsStringPool);
Streamer->emitAppleNames(AppleNames);
Streamer->emitAppleNamespaces(AppleNamespaces);
Streamer->emitAppleTypes(AppleTypes);
Streamer->emitAppleObjc(AppleObjc);
}
};
// FIXME: The DwarfLinker can have some very deep recursion that can max
// out the (significantly smaller) stack when using threads. We don't
// want this limitation when we only have a single thread.
if (Options.Threads == 1) {
AnalyzeLambda();
CloneLambda();
} else {
ThreadPool pool(2);
pool.async(AnalyzeLambda);
pool.async(CloneLambda);
pool.wait();
}
return Options.NoOutput ? true : Streamer->finish(Map);
}
bool linkDwarf(raw_fd_ostream &OutFile, const DebugMap &DM,
const LinkOptions &Options) {
DwarfLinker Linker(OutFile, Options);
return Linker.link(DM);
}
} // namespace dsymutil
} // namespace llvm
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