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llvm-project/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
Nikita Popov 979c275097
[IR] Store Triple in Module (NFC) (#129868) 
The module currently stores the target triple as a string. This means
that any code that wants to actually use the triple first has to
instantiate a Triple, which is somewhat expensive. The change in #121652
caused a moderate compile-time regression due to this. While it would be
easy enough to work around, I think that architecturally, it makes more
sense to store the parsed Triple in the module, so that it can always be
directly queried.

For this change, I've opted not to add any magic conversions between
std::string and Triple for backwards-compatibilty purses, and instead
write out needed Triple()s or str()s explicitly. This is because I think
a decent number of them should be changed to work on Triple as well, to
avoid unnecessary conversions back and forth.

The only interesting part in this patch is that the default triple is
Triple("") instead of Triple() to preserve existing behavior. The former
defaults to using the ELF object format instead of unknown object
format. We should fix that as well.
2025-03-06 10:27:47 +01:00

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//===- llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp ----------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file contains support for writing Microsoft CodeView debug info.
//
//===----------------------------------------------------------------------===//
#include "CodeViewDebug.h"
#include "llvm/ADT/APSInt.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallBitVector.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/TinyPtrVector.h"
#include "llvm/ADT/Twine.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/LexicalScopes.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/TargetFrameLowering.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/DebugInfo/CodeView/CVTypeVisitor.h"
#include "llvm/DebugInfo/CodeView/CodeViewRecordIO.h"
#include "llvm/DebugInfo/CodeView/ContinuationRecordBuilder.h"
#include "llvm/DebugInfo/CodeView/DebugInlineeLinesSubsection.h"
#include "llvm/DebugInfo/CodeView/EnumTables.h"
#include "llvm/DebugInfo/CodeView/Line.h"
#include "llvm/DebugInfo/CodeView/SymbolRecord.h"
#include "llvm/DebugInfo/CodeView/TypeRecord.h"
#include "llvm/DebugInfo/CodeView/TypeTableCollection.h"
#include "llvm/DebugInfo/CodeView/TypeVisitorCallbackPipeline.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Module.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCSectionCOFF.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/BinaryStreamWriter.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/SMLoc.h"
#include "llvm/Support/ScopedPrinter.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/TargetParser/Triple.h"
#include <algorithm>
#include <cassert>
#include <cctype>
#include <cstddef>
#include <limits>
using namespace llvm;
using namespace llvm::codeview;
namespace {
class CVMCAdapter : public CodeViewRecordStreamer {
public:
CVMCAdapter(MCStreamer &OS, TypeCollection &TypeTable)
: OS(&OS), TypeTable(TypeTable) {}
void emitBytes(StringRef Data) override { OS->emitBytes(Data); }
void emitIntValue(uint64_t Value, unsigned Size) override {
OS->emitIntValueInHex(Value, Size);
}
void emitBinaryData(StringRef Data) override { OS->emitBinaryData(Data); }
void AddComment(const Twine &T) override { OS->AddComment(T); }
void AddRawComment(const Twine &T) override { OS->emitRawComment(T); }
bool isVerboseAsm() override { return OS->isVerboseAsm(); }
std::string getTypeName(TypeIndex TI) override {
std::string TypeName;
if (!TI.isNoneType()) {
if (TI.isSimple())
TypeName = std::string(TypeIndex::simpleTypeName(TI));
else
TypeName = std::string(TypeTable.getTypeName(TI));
}
return TypeName;
}
private:
MCStreamer *OS = nullptr;
TypeCollection &TypeTable;
};
} // namespace
static CPUType mapArchToCVCPUType(Triple::ArchType Type) {
switch (Type) {
case Triple::ArchType::x86:
return CPUType::Pentium3;
case Triple::ArchType::x86_64:
return CPUType::X64;
case Triple::ArchType::thumb:
// LLVM currently doesn't support Windows CE and so thumb
// here is indiscriminately mapped to ARMNT specifically.
return CPUType::ARMNT;
case Triple::ArchType::aarch64:
return CPUType::ARM64;
case Triple::ArchType::mipsel:
return CPUType::MIPS;
default:
report_fatal_error("target architecture doesn't map to a CodeView CPUType");
}
}
CodeViewDebug::CodeViewDebug(AsmPrinter *AP)
: DebugHandlerBase(AP), OS(*Asm->OutStreamer), TypeTable(Allocator) {}
StringRef CodeViewDebug::getFullFilepath(const DIFile *File) {
std::string &Filepath = FileToFilepathMap[File];
if (!Filepath.empty())
return Filepath;
StringRef Dir = File->getDirectory(), Filename = File->getFilename();
// If this is a Unix-style path, just use it as is. Don't try to canonicalize
// it textually because one of the path components could be a symlink.
if (Dir.starts_with("/") || Filename.starts_with("/")) {
if (llvm::sys::path::is_absolute(Filename, llvm::sys::path::Style::posix))
return Filename;
Filepath = std::string(Dir);
if (Dir.back() != '/')
Filepath += '/';
Filepath += Filename;
return Filepath;
}
// Clang emits directory and relative filename info into the IR, but CodeView
// operates on full paths. We could change Clang to emit full paths too, but
// that would increase the IR size and probably not needed for other users.
// For now, just concatenate and canonicalize the path here.
if (Filename.find(':') == 1)
Filepath = std::string(Filename);
else
Filepath = (Dir + "\\" + Filename).str();
// Canonicalize the path. We have to do it textually because we may no longer
// have access the file in the filesystem.
// First, replace all slashes with backslashes.
std::replace(Filepath.begin(), Filepath.end(), '/', '\\');
// Remove all "\.\" with "\".
size_t Cursor = 0;
while ((Cursor = Filepath.find("\\.\\", Cursor)) != std::string::npos)
Filepath.erase(Cursor, 2);
// Replace all "\XXX\..\" with "\". Don't try too hard though as the original
// path should be well-formatted, e.g. start with a drive letter, etc.
Cursor = 0;
while ((Cursor = Filepath.find("\\..\\", Cursor)) != std::string::npos) {
// Something's wrong if the path starts with "\..\", abort.
if (Cursor == 0)
break;
size_t PrevSlash = Filepath.rfind('\\', Cursor - 1);
if (PrevSlash == std::string::npos)
// Something's wrong, abort.
break;
Filepath.erase(PrevSlash, Cursor + 3 - PrevSlash);
// The next ".." might be following the one we've just erased.
Cursor = PrevSlash;
}
// Remove all duplicate backslashes.
Cursor = 0;
while ((Cursor = Filepath.find("\\\\", Cursor)) != std::string::npos)
Filepath.erase(Cursor, 1);
return Filepath;
}
unsigned CodeViewDebug::maybeRecordFile(const DIFile *F) {
StringRef FullPath = getFullFilepath(F);
unsigned NextId = FileIdMap.size() + 1;
auto Insertion = FileIdMap.insert(std::make_pair(FullPath, NextId));
if (Insertion.second) {
// We have to compute the full filepath and emit a .cv_file directive.
ArrayRef<uint8_t> ChecksumAsBytes;
FileChecksumKind CSKind = FileChecksumKind::None;
if (F->getChecksum()) {
std::string Checksum = fromHex(F->getChecksum()->Value);
void *CKMem = OS.getContext().allocate(Checksum.size(), 1);
memcpy(CKMem, Checksum.data(), Checksum.size());
ChecksumAsBytes = ArrayRef<uint8_t>(
reinterpret_cast<const uint8_t *>(CKMem), Checksum.size());
switch (F->getChecksum()->Kind) {
case DIFile::CSK_MD5:
CSKind = FileChecksumKind::MD5;
break;
case DIFile::CSK_SHA1:
CSKind = FileChecksumKind::SHA1;
break;
case DIFile::CSK_SHA256:
CSKind = FileChecksumKind::SHA256;
break;
}
}
bool Success = OS.emitCVFileDirective(NextId, FullPath, ChecksumAsBytes,
static_cast<unsigned>(CSKind));
(void)Success;
assert(Success && ".cv_file directive failed");
}
return Insertion.first->second;
}
CodeViewDebug::InlineSite &
CodeViewDebug::getInlineSite(const DILocation *InlinedAt,
const DISubprogram *Inlinee) {
auto SiteInsertion = CurFn->InlineSites.insert({InlinedAt, InlineSite()});
InlineSite *Site = &SiteInsertion.first->second;
if (SiteInsertion.second) {
unsigned ParentFuncId = CurFn->FuncId;
if (const DILocation *OuterIA = InlinedAt->getInlinedAt())
ParentFuncId =
getInlineSite(OuterIA, InlinedAt->getScope()->getSubprogram())
.SiteFuncId;
Site->SiteFuncId = NextFuncId++;
OS.emitCVInlineSiteIdDirective(
Site->SiteFuncId, ParentFuncId, maybeRecordFile(InlinedAt->getFile()),
InlinedAt->getLine(), InlinedAt->getColumn(), SMLoc());
Site->Inlinee = Inlinee;
InlinedSubprograms.insert(Inlinee);
auto InlineeIdx = getFuncIdForSubprogram(Inlinee);
if (InlinedAt->getInlinedAt() == nullptr)
CurFn->Inlinees.insert(InlineeIdx);
}
return *Site;
}
static StringRef getPrettyScopeName(const DIScope *Scope) {
StringRef ScopeName = Scope->getName();
if (!ScopeName.empty())
return ScopeName;
switch (Scope->getTag()) {
case dwarf::DW_TAG_enumeration_type:
case dwarf::DW_TAG_class_type:
case dwarf::DW_TAG_structure_type:
case dwarf::DW_TAG_union_type:
return "<unnamed-tag>";
case dwarf::DW_TAG_namespace:
return "`anonymous namespace'";
default:
return StringRef();
}
}
const DISubprogram *CodeViewDebug::collectParentScopeNames(
const DIScope *Scope, SmallVectorImpl<StringRef> &QualifiedNameComponents) {
const DISubprogram *ClosestSubprogram = nullptr;
while (Scope != nullptr) {
if (ClosestSubprogram == nullptr)
ClosestSubprogram = dyn_cast<DISubprogram>(Scope);
// If a type appears in a scope chain, make sure it gets emitted. The
// frontend will be responsible for deciding if this should be a forward
// declaration or a complete type.
if (const auto *Ty = dyn_cast<DICompositeType>(Scope))
DeferredCompleteTypes.push_back(Ty);
StringRef ScopeName = getPrettyScopeName(Scope);
if (!ScopeName.empty())
QualifiedNameComponents.push_back(ScopeName);
Scope = Scope->getScope();
}
return ClosestSubprogram;
}
static std::string formatNestedName(ArrayRef<StringRef> QualifiedNameComponents,
StringRef TypeName) {
std::string FullyQualifiedName;
for (StringRef QualifiedNameComponent :
llvm::reverse(QualifiedNameComponents)) {
FullyQualifiedName.append(std::string(QualifiedNameComponent));
FullyQualifiedName.append("::");
}
FullyQualifiedName.append(std::string(TypeName));
return FullyQualifiedName;
}
struct CodeViewDebug::TypeLoweringScope {
TypeLoweringScope(CodeViewDebug &CVD) : CVD(CVD) { ++CVD.TypeEmissionLevel; }
~TypeLoweringScope() {
// Don't decrement TypeEmissionLevel until after emitting deferred types, so
// inner TypeLoweringScopes don't attempt to emit deferred types.
if (CVD.TypeEmissionLevel == 1)
CVD.emitDeferredCompleteTypes();
--CVD.TypeEmissionLevel;
}
CodeViewDebug &CVD;
};
std::string CodeViewDebug::getFullyQualifiedName(const DIScope *Scope,
StringRef Name) {
// Ensure types in the scope chain are emitted as soon as possible.
// This can create otherwise a situation where S_UDTs are emitted while
// looping in emitDebugInfoForUDTs.
TypeLoweringScope S(*this);
SmallVector<StringRef, 5> QualifiedNameComponents;
collectParentScopeNames(Scope, QualifiedNameComponents);
return formatNestedName(QualifiedNameComponents, Name);
}
std::string CodeViewDebug::getFullyQualifiedName(const DIScope *Ty) {
const DIScope *Scope = Ty->getScope();
return getFullyQualifiedName(Scope, getPrettyScopeName(Ty));
}
TypeIndex CodeViewDebug::getScopeIndex(const DIScope *Scope) {
// No scope means global scope and that uses the zero index.
//
// We also use zero index when the scope is a DISubprogram
// to suppress the emission of LF_STRING_ID for the function,
// which can trigger a link-time error with the linker in
// VS2019 version 16.11.2 or newer.
// Note, however, skipping the debug info emission for the DISubprogram
// is a temporary fix. The root issue here is that we need to figure out
// the proper way to encode a function nested in another function
// (as introduced by the Fortran 'contains' keyword) in CodeView.
if (!Scope || isa<DIFile>(Scope) || isa<DISubprogram>(Scope))
return TypeIndex();
assert(!isa<DIType>(Scope) && "shouldn't make a namespace scope for a type");
// Check if we've already translated this scope.
auto I = TypeIndices.find({Scope, nullptr});
if (I != TypeIndices.end())
return I->second;
// Build the fully qualified name of the scope.
std::string ScopeName = getFullyQualifiedName(Scope);
StringIdRecord SID(TypeIndex(), ScopeName);
auto TI = TypeTable.writeLeafType(SID);
return recordTypeIndexForDINode(Scope, TI);
}
static StringRef removeTemplateArgs(StringRef Name) {
// Remove template args from the display name. Assume that the template args
// are the last thing in the name.
if (Name.empty() || Name.back() != '>')
return Name;
int OpenBrackets = 0;
for (int i = Name.size() - 1; i >= 0; --i) {
if (Name[i] == '>')
++OpenBrackets;
else if (Name[i] == '<') {
--OpenBrackets;
if (OpenBrackets == 0)
return Name.substr(0, i);
}
}
return Name;
}
TypeIndex CodeViewDebug::getFuncIdForSubprogram(const DISubprogram *SP) {
assert(SP);
// Check if we've already translated this subprogram.
auto I = TypeIndices.find({SP, nullptr});
if (I != TypeIndices.end())
return I->second;
// The display name includes function template arguments. Drop them to match
// MSVC. We need to have the template arguments in the DISubprogram name
// because they are used in other symbol records, such as S_GPROC32_IDs.
StringRef DisplayName = removeTemplateArgs(SP->getName());
const DIScope *Scope = SP->getScope();
TypeIndex TI;
if (const auto *Class = dyn_cast_or_null<DICompositeType>(Scope)) {
// If the scope is a DICompositeType, then this must be a method. Member
// function types take some special handling, and require access to the
// subprogram.
TypeIndex ClassType = getTypeIndex(Class);
MemberFuncIdRecord MFuncId(ClassType, getMemberFunctionType(SP, Class),
DisplayName);
TI = TypeTable.writeLeafType(MFuncId);
} else {
// Otherwise, this must be a free function.
TypeIndex ParentScope = getScopeIndex(Scope);
FuncIdRecord FuncId(ParentScope, getTypeIndex(SP->getType()), DisplayName);
TI = TypeTable.writeLeafType(FuncId);
}
return recordTypeIndexForDINode(SP, TI);
}
static bool isNonTrivial(const DICompositeType *DCTy) {
return ((DCTy->getFlags() & DINode::FlagNonTrivial) == DINode::FlagNonTrivial);
}
static FunctionOptions
getFunctionOptions(const DISubroutineType *Ty,
const DICompositeType *ClassTy = nullptr,
StringRef SPName = StringRef("")) {
FunctionOptions FO = FunctionOptions::None;
const DIType *ReturnTy = nullptr;
if (auto TypeArray = Ty->getTypeArray()) {
if (TypeArray.size())
ReturnTy = TypeArray[0];
}
// Add CxxReturnUdt option to functions that return nontrivial record types
// or methods that return record types.
if (auto *ReturnDCTy = dyn_cast_or_null<DICompositeType>(ReturnTy))
if (isNonTrivial(ReturnDCTy) || ClassTy)
FO |= FunctionOptions::CxxReturnUdt;
// DISubroutineType is unnamed. Use DISubprogram's i.e. SPName in comparison.
if (ClassTy && isNonTrivial(ClassTy) && SPName == ClassTy->getName()) {
FO |= FunctionOptions::Constructor;
// TODO: put the FunctionOptions::ConstructorWithVirtualBases flag.
}
return FO;
}
TypeIndex CodeViewDebug::getMemberFunctionType(const DISubprogram *SP,
const DICompositeType *Class) {
// Always use the method declaration as the key for the function type. The
// method declaration contains the this adjustment.
if (SP->getDeclaration())
SP = SP->getDeclaration();
assert(!SP->getDeclaration() && "should use declaration as key");
// Key the MemberFunctionRecord into the map as {SP, Class}. It won't collide
// with the MemberFuncIdRecord, which is keyed in as {SP, nullptr}.
auto I = TypeIndices.find({SP, Class});
if (I != TypeIndices.end())
return I->second;
// Make sure complete type info for the class is emitted *after* the member
// function type, as the complete class type is likely to reference this
// member function type.
TypeLoweringScope S(*this);
const bool IsStaticMethod = (SP->getFlags() & DINode::FlagStaticMember) != 0;
FunctionOptions FO = getFunctionOptions(SP->getType(), Class, SP->getName());
TypeIndex TI = lowerTypeMemberFunction(
SP->getType(), Class, SP->getThisAdjustment(), IsStaticMethod, FO);
return recordTypeIndexForDINode(SP, TI, Class);
}
TypeIndex CodeViewDebug::recordTypeIndexForDINode(const DINode *Node,
TypeIndex TI,
const DIType *ClassTy) {
auto InsertResult = TypeIndices.insert({{Node, ClassTy}, TI});
(void)InsertResult;
assert(InsertResult.second && "DINode was already assigned a type index");
return TI;
}
unsigned CodeViewDebug::getPointerSizeInBytes() {
return MMI->getModule()->getDataLayout().getPointerSizeInBits() / 8;
}
void CodeViewDebug::recordLocalVariable(LocalVariable &&Var,
const LexicalScope *LS) {
if (const DILocation *InlinedAt = LS->getInlinedAt()) {
// This variable was inlined. Associate it with the InlineSite.
const DISubprogram *Inlinee = Var.DIVar->getScope()->getSubprogram();
InlineSite &Site = getInlineSite(InlinedAt, Inlinee);
Site.InlinedLocals.emplace_back(std::move(Var));
} else {
// This variable goes into the corresponding lexical scope.
ScopeVariables[LS].emplace_back(std::move(Var));
}
}
static void addLocIfNotPresent(SmallVectorImpl<const DILocation *> &Locs,
const DILocation *Loc) {
if (!llvm::is_contained(Locs, Loc))
Locs.push_back(Loc);
}
void CodeViewDebug::maybeRecordLocation(const DebugLoc &DL,
const MachineFunction *MF) {
// Skip this instruction if it has the same location as the previous one.
if (!DL || DL == PrevInstLoc)
return;
const DIScope *Scope = DL->getScope();
if (!Scope)
return;
// Skip this line if it is longer than the maximum we can record.
LineInfo LI(DL.getLine(), DL.getLine(), /*IsStatement=*/true);
if (LI.getStartLine() != DL.getLine() || LI.isAlwaysStepInto() ||
LI.isNeverStepInto())
return;
ColumnInfo CI(DL.getCol(), /*EndColumn=*/0);
if (CI.getStartColumn() != DL.getCol())
return;
if (!CurFn->HaveLineInfo)
CurFn->HaveLineInfo = true;
unsigned FileId = 0;
if (PrevInstLoc.get() && PrevInstLoc->getFile() == DL->getFile())
FileId = CurFn->LastFileId;
else
FileId = CurFn->LastFileId = maybeRecordFile(DL->getFile());
PrevInstLoc = DL;
unsigned FuncId = CurFn->FuncId;
if (const DILocation *SiteLoc = DL->getInlinedAt()) {
const DILocation *Loc = DL.get();
// If this location was actually inlined from somewhere else, give it the ID
// of the inline call site.
FuncId =
getInlineSite(SiteLoc, Loc->getScope()->getSubprogram()).SiteFuncId;
// Ensure we have links in the tree of inline call sites.
bool FirstLoc = true;
while ((SiteLoc = Loc->getInlinedAt())) {
InlineSite &Site =
getInlineSite(SiteLoc, Loc->getScope()->getSubprogram());
if (!FirstLoc)
addLocIfNotPresent(Site.ChildSites, Loc);
FirstLoc = false;
Loc = SiteLoc;
}
addLocIfNotPresent(CurFn->ChildSites, Loc);
}
OS.emitCVLocDirective(FuncId, FileId, DL.getLine(), DL.getCol(),
/*PrologueEnd=*/false, /*IsStmt=*/false,
DL->getFilename(), SMLoc());
}
void CodeViewDebug::emitCodeViewMagicVersion() {
OS.emitValueToAlignment(Align(4));
OS.AddComment("Debug section magic");
OS.emitInt32(COFF::DEBUG_SECTION_MAGIC);
}
static SourceLanguage MapDWLangToCVLang(unsigned DWLang) {
switch (DWLang) {
case dwarf::DW_LANG_C:
case dwarf::DW_LANG_C89:
case dwarf::DW_LANG_C99:
case dwarf::DW_LANG_C11:
return SourceLanguage::C;
case dwarf::DW_LANG_C_plus_plus:
case dwarf::DW_LANG_C_plus_plus_03:
case dwarf::DW_LANG_C_plus_plus_11:
case dwarf::DW_LANG_C_plus_plus_14:
return SourceLanguage::Cpp;
case dwarf::DW_LANG_Fortran77:
case dwarf::DW_LANG_Fortran90:
case dwarf::DW_LANG_Fortran95:
case dwarf::DW_LANG_Fortran03:
case dwarf::DW_LANG_Fortran08:
return SourceLanguage::Fortran;
case dwarf::DW_LANG_Pascal83:
return SourceLanguage::Pascal;
case dwarf::DW_LANG_Cobol74:
case dwarf::DW_LANG_Cobol85:
return SourceLanguage::Cobol;
case dwarf::DW_LANG_Java:
return SourceLanguage::Java;
case dwarf::DW_LANG_D:
return SourceLanguage::D;
case dwarf::DW_LANG_Swift:
return SourceLanguage::Swift;
case dwarf::DW_LANG_Rust:
return SourceLanguage::Rust;
case dwarf::DW_LANG_ObjC:
return SourceLanguage::ObjC;
case dwarf::DW_LANG_ObjC_plus_plus:
return SourceLanguage::ObjCpp;
default:
// There's no CodeView representation for this language, and CV doesn't
// have an "unknown" option for the language field, so we'll use MASM,
// as it's very low level.
return SourceLanguage::Masm;
}
}
void CodeViewDebug::beginModule(Module *M) {
// If module doesn't have named metadata anchors or COFF debug section
// is not available, skip any debug info related stuff.
if (!Asm->hasDebugInfo() ||
!Asm->getObjFileLowering().getCOFFDebugSymbolsSection()) {
Asm = nullptr;
return;
}
TheCPU = mapArchToCVCPUType(M->getTargetTriple().getArch());
// Get the current source language.
const MDNode *Node = *M->debug_compile_units_begin();
const auto *CU = cast<DICompileUnit>(Node);
CurrentSourceLanguage = MapDWLangToCVLang(CU->getSourceLanguage());
collectGlobalVariableInfo();
// Check if we should emit type record hashes.
ConstantInt *GH =
mdconst::extract_or_null<ConstantInt>(M->getModuleFlag("CodeViewGHash"));
EmitDebugGlobalHashes = GH && !GH->isZero();
}
void CodeViewDebug::endModule() {
if (!Asm || !Asm->hasDebugInfo())
return;
// The COFF .debug$S section consists of several subsections, each starting
// with a 4-byte control code (e.g. 0xF1, 0xF2, etc) and then a 4-byte length
// of the payload followed by the payload itself. The subsections are 4-byte
// aligned.
// Use the generic .debug$S section, and make a subsection for all the inlined
// subprograms.
switchToDebugSectionForSymbol(nullptr);
MCSymbol *CompilerInfo = beginCVSubsection(DebugSubsectionKind::Symbols);
emitObjName();
emitCompilerInformation();
endCVSubsection(CompilerInfo);
emitInlineeLinesSubsection();
// Emit per-function debug information.
for (auto &P : FnDebugInfo)
if (!P.first->isDeclarationForLinker())
emitDebugInfoForFunction(P.first, *P.second);
// Get types used by globals without emitting anything.
// This is meant to collect all static const data members so they can be
// emitted as globals.
collectDebugInfoForGlobals();
// Emit retained types.
emitDebugInfoForRetainedTypes();
// Emit global variable debug information.
setCurrentSubprogram(nullptr);
emitDebugInfoForGlobals();
// Switch back to the generic .debug$S section after potentially processing
// comdat symbol sections.
switchToDebugSectionForSymbol(nullptr);
// Emit UDT records for any types used by global variables.
if (!GlobalUDTs.empty()) {
MCSymbol *SymbolsEnd = beginCVSubsection(DebugSubsectionKind::Symbols);
emitDebugInfoForUDTs(GlobalUDTs);
endCVSubsection(SymbolsEnd);
}
// This subsection holds a file index to offset in string table table.
OS.AddComment("File index to string table offset subsection");
OS.emitCVFileChecksumsDirective();
// This subsection holds the string table.
OS.AddComment("String table");
OS.emitCVStringTableDirective();
// Emit S_BUILDINFO, which points to LF_BUILDINFO. Put this in its own symbol
// subsection in the generic .debug$S section at the end. There is no
// particular reason for this ordering other than to match MSVC.
emitBuildInfo();
// Emit type information and hashes last, so that any types we translate while
// emitting function info are included.
emitTypeInformation();
if (EmitDebugGlobalHashes)
emitTypeGlobalHashes();
clear();
}
static void
emitNullTerminatedSymbolName(MCStreamer &OS, StringRef S,
unsigned MaxFixedRecordLength = 0xF00) {
// The maximum CV record length is 0xFF00. Most of the strings we emit appear
// after a fixed length portion of the record. The fixed length portion should
// always be less than 0xF00 (3840) bytes, so truncate the string so that the
// overall record size is less than the maximum allowed.
SmallString<32> NullTerminatedString(
S.take_front(MaxRecordLength - MaxFixedRecordLength - 1));
NullTerminatedString.push_back('\0');
OS.emitBytes(NullTerminatedString);
}
void CodeViewDebug::emitTypeInformation() {
if (TypeTable.empty())
return;
// Start the .debug$T or .debug$P section with 0x4.
OS.switchSection(Asm->getObjFileLowering().getCOFFDebugTypesSection());
emitCodeViewMagicVersion();
TypeTableCollection Table(TypeTable.records());
TypeVisitorCallbackPipeline Pipeline;
// To emit type record using Codeview MCStreamer adapter
CVMCAdapter CVMCOS(OS, Table);
TypeRecordMapping typeMapping(CVMCOS);
Pipeline.addCallbackToPipeline(typeMapping);
std::optional<TypeIndex> B = Table.getFirst();
while (B) {
// This will fail if the record data is invalid.
CVType Record = Table.getType(*B);
Error E = codeview::visitTypeRecord(Record, *B, Pipeline);
if (E) {
logAllUnhandledErrors(std::move(E), errs(), "error: ");
llvm_unreachable("produced malformed type record");
}
B = Table.getNext(*B);
}
}
void CodeViewDebug::emitTypeGlobalHashes() {
if (TypeTable.empty())
return;
// Start the .debug$H section with the version and hash algorithm, currently
// hardcoded to version 0, SHA1.
OS.switchSection(Asm->getObjFileLowering().getCOFFGlobalTypeHashesSection());
OS.emitValueToAlignment(Align(4));
OS.AddComment("Magic");
OS.emitInt32(COFF::DEBUG_HASHES_SECTION_MAGIC);
OS.AddComment("Section Version");
OS.emitInt16(0);
OS.AddComment("Hash Algorithm");
OS.emitInt16(uint16_t(GlobalTypeHashAlg::BLAKE3));
TypeIndex TI(TypeIndex::FirstNonSimpleIndex);
for (const auto &GHR : TypeTable.hashes()) {
if (OS.isVerboseAsm()) {
// Emit an EOL-comment describing which TypeIndex this hash corresponds
// to, as well as the stringified SHA1 hash.
SmallString<32> Comment;
raw_svector_ostream CommentOS(Comment);
CommentOS << formatv("{0:X+} [{1}]", TI.getIndex(), GHR);
OS.AddComment(Comment);
++TI;
}
assert(GHR.Hash.size() == 8);
StringRef S(reinterpret_cast<const char *>(GHR.Hash.data()),
GHR.Hash.size());
OS.emitBinaryData(S);
}
}
void CodeViewDebug::emitObjName() {
MCSymbol *CompilerEnd = beginSymbolRecord(SymbolKind::S_OBJNAME);
StringRef PathRef(Asm->TM.Options.ObjectFilenameForDebug);
llvm::SmallString<256> PathStore(PathRef);
if (PathRef.empty() || PathRef == "-") {
// Don't emit the filename if we're writing to stdout or to /dev/null.
PathRef = {};
} else {
PathRef = PathStore;
}
OS.AddComment("Signature");
OS.emitIntValue(0, 4);
OS.AddComment("Object name");
emitNullTerminatedSymbolName(OS, PathRef);
endSymbolRecord(CompilerEnd);
}
namespace {
struct Version {
int Part[4];
};
} // end anonymous namespace
// Takes a StringRef like "clang 4.0.0.0 (other nonsense 123)" and parses out
// the version number.
static Version parseVersion(StringRef Name) {
Version V = {{0}};
int N = 0;
for (const char C : Name) {
if (isdigit(C)) {
V.Part[N] *= 10;
V.Part[N] += C - '0';
V.Part[N] =
std::min<int>(V.Part[N], std::numeric_limits<uint16_t>::max());
} else if (C == '.') {
++N;
if (N >= 4)
return V;
} else if (N > 0)
return V;
}
return V;
}
void CodeViewDebug::emitCompilerInformation() {
MCSymbol *CompilerEnd = beginSymbolRecord(SymbolKind::S_COMPILE3);
uint32_t Flags = 0;
// The low byte of the flags indicates the source language.
Flags = CurrentSourceLanguage;
// TODO: Figure out which other flags need to be set.
if (MMI->getModule()->getProfileSummary(/*IsCS*/ false) != nullptr) {
Flags |= static_cast<uint32_t>(CompileSym3Flags::PGO);
}
using ArchType = llvm::Triple::ArchType;
ArchType Arch = MMI->getModule()->getTargetTriple().getArch();
if (Asm->TM.Options.Hotpatch || Arch == ArchType::thumb ||
Arch == ArchType::aarch64) {
Flags |= static_cast<uint32_t>(CompileSym3Flags::HotPatch);
}
OS.AddComment("Flags and language");
OS.emitInt32(Flags);
OS.AddComment("CPUType");
OS.emitInt16(static_cast<uint64_t>(TheCPU));
NamedMDNode *CUs = MMI->getModule()->getNamedMetadata("llvm.dbg.cu");
const MDNode *Node = *CUs->operands().begin();
const auto *CU = cast<DICompileUnit>(Node);
StringRef CompilerVersion = CU->getProducer();
Version FrontVer = parseVersion(CompilerVersion);
OS.AddComment("Frontend version");
for (int N : FrontVer.Part) {
OS.emitInt16(N);
}
// Some Microsoft tools, like Binscope, expect a backend version number of at
// least 8.something, so we'll coerce the LLVM version into a form that
// guarantees it'll be big enough without really lying about the version.
int Major = 1000 * LLVM_VERSION_MAJOR +
10 * LLVM_VERSION_MINOR +
LLVM_VERSION_PATCH;
// Clamp it for builds that use unusually large version numbers.
Major = std::min<int>(Major, std::numeric_limits<uint16_t>::max());
Version BackVer = {{ Major, 0, 0, 0 }};
OS.AddComment("Backend version");
for (int N : BackVer.Part)
OS.emitInt16(N);
OS.AddComment("Null-terminated compiler version string");
emitNullTerminatedSymbolName(OS, CompilerVersion);
endSymbolRecord(CompilerEnd);
}
static TypeIndex getStringIdTypeIdx(GlobalTypeTableBuilder &TypeTable,
StringRef S) {
StringIdRecord SIR(TypeIndex(0x0), S);
return TypeTable.writeLeafType(SIR);
}
void CodeViewDebug::emitBuildInfo() {
// First, make LF_BUILDINFO. It's a sequence of strings with various bits of
// build info. The known prefix is:
// - Absolute path of current directory
// - Compiler path
// - Main source file path, relative to CWD or absolute
// - Type server PDB file
// - Canonical compiler command line
// If frontend and backend compilation are separated (think llc or LTO), it's
// not clear if the compiler path should refer to the executable for the
// frontend or the backend. Leave it blank for now.
TypeIndex BuildInfoArgs[BuildInfoRecord::MaxArgs] = {};
NamedMDNode *CUs = MMI->getModule()->getNamedMetadata("llvm.dbg.cu");
const MDNode *Node = *CUs->operands().begin(); // FIXME: Multiple CUs.
const auto *CU = cast<DICompileUnit>(Node);
const DIFile *MainSourceFile = CU->getFile();
BuildInfoArgs[BuildInfoRecord::CurrentDirectory] =
getStringIdTypeIdx(TypeTable, MainSourceFile->getDirectory());
BuildInfoArgs[BuildInfoRecord::SourceFile] =
getStringIdTypeIdx(TypeTable, MainSourceFile->getFilename());
// FIXME: PDB is intentionally blank unless we implement /Zi type servers.
BuildInfoArgs[BuildInfoRecord::TypeServerPDB] =
getStringIdTypeIdx(TypeTable, "");
BuildInfoArgs[BuildInfoRecord::BuildTool] =
getStringIdTypeIdx(TypeTable, Asm->TM.Options.MCOptions.Argv0);
BuildInfoArgs[BuildInfoRecord::CommandLine] = getStringIdTypeIdx(
TypeTable, Asm->TM.Options.MCOptions.CommandlineArgs);
BuildInfoRecord BIR(BuildInfoArgs);
TypeIndex BuildInfoIndex = TypeTable.writeLeafType(BIR);
// Make a new .debug$S subsection for the S_BUILDINFO record, which points
// from the module symbols into the type stream.
MCSymbol *BISubsecEnd = beginCVSubsection(DebugSubsectionKind::Symbols);
MCSymbol *BIEnd = beginSymbolRecord(SymbolKind::S_BUILDINFO);
OS.AddComment("LF_BUILDINFO index");
OS.emitInt32(BuildInfoIndex.getIndex());
endSymbolRecord(BIEnd);
endCVSubsection(BISubsecEnd);
}
void CodeViewDebug::emitInlineeLinesSubsection() {
if (InlinedSubprograms.empty())
return;
OS.AddComment("Inlinee lines subsection");
MCSymbol *InlineEnd = beginCVSubsection(DebugSubsectionKind::InlineeLines);
// We emit the checksum info for files. This is used by debuggers to
// determine if a pdb matches the source before loading it. Visual Studio,
// for instance, will display a warning that the breakpoints are not valid if
// the pdb does not match the source.
OS.AddComment("Inlinee lines signature");
OS.emitInt32(unsigned(InlineeLinesSignature::Normal));
for (const DISubprogram *SP : InlinedSubprograms) {
assert(TypeIndices.count({SP, nullptr}));
TypeIndex InlineeIdx = TypeIndices[{SP, nullptr}];
OS.addBlankLine();
unsigned FileId = maybeRecordFile(SP->getFile());
OS.AddComment("Inlined function " + SP->getName() + " starts at " +
SP->getFilename() + Twine(':') + Twine(SP->getLine()));
OS.addBlankLine();
OS.AddComment("Type index of inlined function");
OS.emitInt32(InlineeIdx.getIndex());
OS.AddComment("Offset into filechecksum table");
OS.emitCVFileChecksumOffsetDirective(FileId);
OS.AddComment("Starting line number");
OS.emitInt32(SP->getLine());
}
endCVSubsection(InlineEnd);
}
void CodeViewDebug::emitInlinedCallSite(const FunctionInfo &FI,
const DILocation *InlinedAt,
const InlineSite &Site) {
assert(TypeIndices.count({Site.Inlinee, nullptr}));
TypeIndex InlineeIdx = TypeIndices[{Site.Inlinee, nullptr}];
// SymbolRecord
MCSymbol *InlineEnd = beginSymbolRecord(SymbolKind::S_INLINESITE);
OS.AddComment("PtrParent");
OS.emitInt32(0);
OS.AddComment("PtrEnd");
OS.emitInt32(0);
OS.AddComment("Inlinee type index");
OS.emitInt32(InlineeIdx.getIndex());
unsigned FileId = maybeRecordFile(Site.Inlinee->getFile());
unsigned StartLineNum = Site.Inlinee->getLine();
OS.emitCVInlineLinetableDirective(Site.SiteFuncId, FileId, StartLineNum,
FI.Begin, FI.End);
endSymbolRecord(InlineEnd);
emitLocalVariableList(FI, Site.InlinedLocals);
// Recurse on child inlined call sites before closing the scope.
for (const DILocation *ChildSite : Site.ChildSites) {
auto I = FI.InlineSites.find(ChildSite);
assert(I != FI.InlineSites.end() &&
"child site not in function inline site map");
emitInlinedCallSite(FI, ChildSite, I->second);
}
// Close the scope.
emitEndSymbolRecord(SymbolKind::S_INLINESITE_END);
}
void CodeViewDebug::switchToDebugSectionForSymbol(const MCSymbol *GVSym) {
// If we have a symbol, it may be in a section that is COMDAT. If so, find the
// comdat key. A section may be comdat because of -ffunction-sections or
// because it is comdat in the IR.
MCSectionCOFF *GVSec =
GVSym ? dyn_cast<MCSectionCOFF>(&GVSym->getSection()) : nullptr;
const MCSymbol *KeySym = GVSec ? GVSec->getCOMDATSymbol() : nullptr;
MCSectionCOFF *DebugSec = cast<MCSectionCOFF>(
Asm->getObjFileLowering().getCOFFDebugSymbolsSection());
DebugSec = OS.getContext().getAssociativeCOFFSection(DebugSec, KeySym);
OS.switchSection(DebugSec);
// Emit the magic version number if this is the first time we've switched to
// this section.
if (ComdatDebugSections.insert(DebugSec).second)
emitCodeViewMagicVersion();
}
// Emit an S_THUNK32/S_END symbol pair for a thunk routine.
// The only supported thunk ordinal is currently the standard type.
void CodeViewDebug::emitDebugInfoForThunk(const Function *GV,
FunctionInfo &FI,
const MCSymbol *Fn) {
std::string FuncName =
std::string(GlobalValue::dropLLVMManglingEscape(GV->getName()));
const ThunkOrdinal ordinal = ThunkOrdinal::Standard; // Only supported kind.
OS.AddComment("Symbol subsection for " + Twine(FuncName));
MCSymbol *SymbolsEnd = beginCVSubsection(DebugSubsectionKind::Symbols);
// Emit S_THUNK32
MCSymbol *ThunkRecordEnd = beginSymbolRecord(SymbolKind::S_THUNK32);
OS.AddComment("PtrParent");
OS.emitInt32(0);
OS.AddComment("PtrEnd");
OS.emitInt32(0);
OS.AddComment("PtrNext");
OS.emitInt32(0);
OS.AddComment("Thunk section relative address");
OS.emitCOFFSecRel32(Fn, /*Offset=*/0);
OS.AddComment("Thunk section index");
OS.emitCOFFSectionIndex(Fn);
OS.AddComment("Code size");
OS.emitAbsoluteSymbolDiff(FI.End, Fn, 2);
OS.AddComment("Ordinal");
OS.emitInt8(unsigned(ordinal));
OS.AddComment("Function name");
emitNullTerminatedSymbolName(OS, FuncName);
// Additional fields specific to the thunk ordinal would go here.
endSymbolRecord(ThunkRecordEnd);
// Local variables/inlined routines are purposely omitted here. The point of
// marking this as a thunk is so Visual Studio will NOT stop in this routine.
// Emit S_PROC_ID_END
emitEndSymbolRecord(SymbolKind::S_PROC_ID_END);
endCVSubsection(SymbolsEnd);
}
void CodeViewDebug::emitDebugInfoForFunction(const Function *GV,
FunctionInfo &FI) {
// For each function there is a separate subsection which holds the PC to
// file:line table.
const MCSymbol *Fn = Asm->getSymbol(GV);
assert(Fn);
// Switch to the to a comdat section, if appropriate.
switchToDebugSectionForSymbol(Fn);
std::string FuncName;
auto *SP = GV->getSubprogram();
assert(SP);
setCurrentSubprogram(SP);
if (SP->isThunk()) {
emitDebugInfoForThunk(GV, FI, Fn);
return;
}
// If we have a display name, build the fully qualified name by walking the
// chain of scopes.
if (!SP->getName().empty())
FuncName = getFullyQualifiedName(SP->getScope(), SP->getName());
// If our DISubprogram name is empty, use the mangled name.
if (FuncName.empty())
FuncName = std::string(GlobalValue::dropLLVMManglingEscape(GV->getName()));
// Emit FPO data, but only on 32-bit x86. No other platforms use it.
if (MMI->getModule()->getTargetTriple().getArch() == Triple::x86)
OS.emitCVFPOData(Fn);
// Emit a symbol subsection, required by VS2012+ to find function boundaries.
OS.AddComment("Symbol subsection for " + Twine(FuncName));
MCSymbol *SymbolsEnd = beginCVSubsection(DebugSubsectionKind::Symbols);
{
SymbolKind ProcKind = GV->hasLocalLinkage() ? SymbolKind::S_LPROC32_ID
: SymbolKind::S_GPROC32_ID;
MCSymbol *ProcRecordEnd = beginSymbolRecord(ProcKind);
// These fields are filled in by tools like CVPACK which run after the fact.
OS.AddComment("PtrParent");
OS.emitInt32(0);
OS.AddComment("PtrEnd");
OS.emitInt32(0);
OS.AddComment("PtrNext");
OS.emitInt32(0);
// This is the important bit that tells the debugger where the function
// code is located and what's its size:
OS.AddComment("Code size");
OS.emitAbsoluteSymbolDiff(FI.End, Fn, 4);
OS.AddComment("Offset after prologue");
OS.emitInt32(0);
OS.AddComment("Offset before epilogue");
OS.emitInt32(0);
OS.AddComment("Function type index");
OS.emitInt32(getFuncIdForSubprogram(GV->getSubprogram()).getIndex());
OS.AddComment("Function section relative address");
OS.emitCOFFSecRel32(Fn, /*Offset=*/0);
OS.AddComment("Function section index");
OS.emitCOFFSectionIndex(Fn);
OS.AddComment("Flags");
ProcSymFlags ProcFlags = ProcSymFlags::HasOptimizedDebugInfo;
if (FI.HasFramePointer)
ProcFlags |= ProcSymFlags::HasFP;
if (GV->hasFnAttribute(Attribute::NoReturn))
ProcFlags |= ProcSymFlags::IsNoReturn;
if (GV->hasFnAttribute(Attribute::NoInline))
ProcFlags |= ProcSymFlags::IsNoInline;
OS.emitInt8(static_cast<uint8_t>(ProcFlags));
// Emit the function display name as a null-terminated string.
OS.AddComment("Function name");
// Truncate the name so we won't overflow the record length field.
emitNullTerminatedSymbolName(OS, FuncName);
endSymbolRecord(ProcRecordEnd);
MCSymbol *FrameProcEnd = beginSymbolRecord(SymbolKind::S_FRAMEPROC);
// Subtract out the CSR size since MSVC excludes that and we include it.
OS.AddComment("FrameSize");
OS.emitInt32(FI.FrameSize - FI.CSRSize);
OS.AddComment("Padding");
OS.emitInt32(0);
OS.AddComment("Offset of padding");
OS.emitInt32(0);
OS.AddComment("Bytes of callee saved registers");
OS.emitInt32(FI.CSRSize);
OS.AddComment("Exception handler offset");
OS.emitInt32(0);
OS.AddComment("Exception handler section");
OS.emitInt16(0);
OS.AddComment("Flags (defines frame register)");
OS.emitInt32(uint32_t(FI.FrameProcOpts));
endSymbolRecord(FrameProcEnd);
emitInlinees(FI.Inlinees);
emitLocalVariableList(FI, FI.Locals);
emitGlobalVariableList(FI.Globals);
emitLexicalBlockList(FI.ChildBlocks, FI);
// Emit inlined call site information. Only emit functions inlined directly
// into the parent function. We'll emit the other sites recursively as part
// of their parent inline site.
for (const DILocation *InlinedAt : FI.ChildSites) {
auto I = FI.InlineSites.find(InlinedAt);
assert(I != FI.InlineSites.end() &&
"child site not in function inline site map");
emitInlinedCallSite(FI, InlinedAt, I->second);
}
for (auto Annot : FI.Annotations) {
MCSymbol *Label = Annot.first;
MDTuple *Strs = cast<MDTuple>(Annot.second);
MCSymbol *AnnotEnd = beginSymbolRecord(SymbolKind::S_ANNOTATION);
OS.emitCOFFSecRel32(Label, /*Offset=*/0);
// FIXME: Make sure we don't overflow the max record size.
OS.emitCOFFSectionIndex(Label);
OS.emitInt16(Strs->getNumOperands());
for (Metadata *MD : Strs->operands()) {
// MDStrings are null terminated, so we can do EmitBytes and get the
// nice .asciz directive.
StringRef Str = cast<MDString>(MD)->getString();
assert(Str.data()[Str.size()] == '\0' && "non-nullterminated MDString");
OS.emitBytes(StringRef(Str.data(), Str.size() + 1));
}
endSymbolRecord(AnnotEnd);
}
for (auto HeapAllocSite : FI.HeapAllocSites) {
const MCSymbol *BeginLabel = std::get<0>(HeapAllocSite);
const MCSymbol *EndLabel = std::get<1>(HeapAllocSite);
const DIType *DITy = std::get<2>(HeapAllocSite);
MCSymbol *HeapAllocEnd = beginSymbolRecord(SymbolKind::S_HEAPALLOCSITE);
OS.AddComment("Call site offset");
OS.emitCOFFSecRel32(BeginLabel, /*Offset=*/0);
OS.AddComment("Call site section index");
OS.emitCOFFSectionIndex(BeginLabel);
OS.AddComment("Call instruction length");
OS.emitAbsoluteSymbolDiff(EndLabel, BeginLabel, 2);
OS.AddComment("Type index");
OS.emitInt32(getCompleteTypeIndex(DITy).getIndex());
endSymbolRecord(HeapAllocEnd);
}
if (SP != nullptr)
emitDebugInfoForUDTs(LocalUDTs);
emitDebugInfoForJumpTables(FI);
// We're done with this function.
emitEndSymbolRecord(SymbolKind::S_PROC_ID_END);
}
endCVSubsection(SymbolsEnd);
// We have an assembler directive that takes care of the whole line table.
OS.emitCVLinetableDirective(FI.FuncId, Fn, FI.End);
}
CodeViewDebug::LocalVarDef
CodeViewDebug::createDefRangeMem(uint16_t CVRegister, int Offset) {
LocalVarDef DR;
DR.InMemory = -1;
DR.DataOffset = Offset;
assert(DR.DataOffset == Offset && "truncation");
DR.IsSubfield = 0;
DR.StructOffset = 0;
DR.CVRegister = CVRegister;
return DR;
}
void CodeViewDebug::collectVariableInfoFromMFTable(
DenseSet<InlinedEntity> &Processed) {
const MachineFunction &MF = *Asm->MF;
const TargetSubtargetInfo &TSI = MF.getSubtarget();
const TargetFrameLowering *TFI = TSI.getFrameLowering();
const TargetRegisterInfo *TRI = TSI.getRegisterInfo();
for (const MachineFunction::VariableDbgInfo &VI :
MF.getInStackSlotVariableDbgInfo()) {
if (!VI.Var)
continue;
assert(VI.Var->isValidLocationForIntrinsic(VI.Loc) &&
"Expected inlined-at fields to agree");
Processed.insert(InlinedEntity(VI.Var, VI.Loc->getInlinedAt()));
LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
// If variable scope is not found then skip this variable.
if (!Scope)
continue;
// If the variable has an attached offset expression, extract it.
// FIXME: Try to handle DW_OP_deref as well.
int64_t ExprOffset = 0;
bool Deref = false;
if (VI.Expr) {
// If there is one DW_OP_deref element, use offset of 0 and keep going.
if (VI.Expr->getNumElements() == 1 &&
VI.Expr->getElement(0) == llvm::dwarf::DW_OP_deref)
Deref = true;
else if (!VI.Expr->extractIfOffset(ExprOffset))
continue;
}
// Get the frame register used and the offset.
Register FrameReg;
StackOffset FrameOffset =
TFI->getFrameIndexReference(*Asm->MF, VI.getStackSlot(), FrameReg);
uint16_t CVReg = TRI->getCodeViewRegNum(FrameReg);
assert(!FrameOffset.getScalable() &&
"Frame offsets with a scalable component are not supported");
// Calculate the label ranges.
LocalVarDef DefRange =
createDefRangeMem(CVReg, FrameOffset.getFixed() + ExprOffset);
LocalVariable Var;
Var.DIVar = VI.Var;
for (const InsnRange &Range : Scope->getRanges()) {
const MCSymbol *Begin = getLabelBeforeInsn(Range.first);
const MCSymbol *End = getLabelAfterInsn(Range.second);
End = End ? End : Asm->getFunctionEnd();
Var.DefRanges[DefRange].emplace_back(Begin, End);
}
if (Deref)
Var.UseReferenceType = true;
recordLocalVariable(std::move(Var), Scope);
}
}
static bool canUseReferenceType(const DbgVariableLocation &Loc) {
return !Loc.LoadChain.empty() && Loc.LoadChain.back() == 0;
}
static bool needsReferenceType(const DbgVariableLocation &Loc) {
return Loc.LoadChain.size() == 2 && Loc.LoadChain.back() == 0;
}
void CodeViewDebug::calculateRanges(
LocalVariable &Var, const DbgValueHistoryMap::Entries &Entries) {
const TargetRegisterInfo *TRI = Asm->MF->getSubtarget().getRegisterInfo();
// Calculate the definition ranges.
for (auto I = Entries.begin(), E = Entries.end(); I != E; ++I) {
const auto &Entry = *I;
if (!Entry.isDbgValue())
continue;
const MachineInstr *DVInst = Entry.getInstr();
assert(DVInst->isDebugValue() && "Invalid History entry");
// FIXME: Find a way to represent constant variables, since they are
// relatively common.
std::optional<DbgVariableLocation> Location =
DbgVariableLocation::extractFromMachineInstruction(*DVInst);
if (!Location)
{
// When we don't have a location this is usually because LLVM has
// transformed it into a constant and we only have an llvm.dbg.value. We
// can't represent these well in CodeView since S_LOCAL only works on
// registers and memory locations. Instead, we will pretend this to be a
// constant value to at least have it show up in the debugger.
auto Op = DVInst->getDebugOperand(0);
if (Op.isImm())
Var.ConstantValue = APSInt(APInt(64, Op.getImm()), false);
continue;
}
// CodeView can only express variables in register and variables in memory
// at a constant offset from a register. However, for variables passed
// indirectly by pointer, it is common for that pointer to be spilled to a
// stack location. For the special case of one offseted load followed by a
// zero offset load (a pointer spilled to the stack), we change the type of
// the local variable from a value type to a reference type. This tricks the
// debugger into doing the load for us.
if (Var.UseReferenceType) {
// We're using a reference type. Drop the last zero offset load.
if (canUseReferenceType(*Location))
Location->LoadChain.pop_back();
else
continue;
} else if (needsReferenceType(*Location)) {
// This location can't be expressed without switching to a reference type.
// Start over using that.
Var.UseReferenceType = true;
Var.DefRanges.clear();
calculateRanges(Var, Entries);
return;
}
// We can only handle a register or an offseted load of a register.
if (Location->Register == 0 || Location->LoadChain.size() > 1)
continue;
// Codeview can only express byte-aligned offsets, ensure that we have a
// byte-boundaried location.
if (Location->FragmentInfo)
if (Location->FragmentInfo->OffsetInBits % 8)
continue;
LocalVarDef DR;
DR.CVRegister = TRI->getCodeViewRegNum(Location->Register);
DR.InMemory = !Location->LoadChain.empty();
DR.DataOffset =
!Location->LoadChain.empty() ? Location->LoadChain.back() : 0;
if (Location->FragmentInfo) {
DR.IsSubfield = true;
DR.StructOffset = Location->FragmentInfo->OffsetInBits / 8;
} else {
DR.IsSubfield = false;
DR.StructOffset = 0;
}
// Compute the label range.
const MCSymbol *Begin = getLabelBeforeInsn(Entry.getInstr());
const MCSymbol *End;
if (Entry.getEndIndex() != DbgValueHistoryMap::NoEntry) {
auto &EndingEntry = Entries[Entry.getEndIndex()];
End = EndingEntry.isDbgValue()
? getLabelBeforeInsn(EndingEntry.getInstr())
: getLabelAfterInsn(EndingEntry.getInstr());
} else
End = Asm->getFunctionEnd();
// If the last range end is our begin, just extend the last range.
// Otherwise make a new range.
SmallVectorImpl<std::pair<const MCSymbol *, const MCSymbol *>> &R =
Var.DefRanges[DR];
if (!R.empty() && R.back().second == Begin)
R.back().second = End;
else
R.emplace_back(Begin, End);
// FIXME: Do more range combining.
}
}
void CodeViewDebug::collectVariableInfo(const DISubprogram *SP) {
DenseSet<InlinedEntity> Processed;
// Grab the variable info that was squirreled away in the MMI side-table.
collectVariableInfoFromMFTable(Processed);
for (const auto &I : DbgValues) {
InlinedEntity IV = I.first;
if (Processed.count(IV))
continue;
const DILocalVariable *DIVar = cast<DILocalVariable>(IV.first);
const DILocation *InlinedAt = IV.second;
// Instruction ranges, specifying where IV is accessible.
const auto &Entries = I.second;
LexicalScope *Scope = nullptr;
if (InlinedAt)
Scope = LScopes.findInlinedScope(DIVar->getScope(), InlinedAt);
else
Scope = LScopes.findLexicalScope(DIVar->getScope());
// If variable scope is not found then skip this variable.
if (!Scope)
continue;
LocalVariable Var;
Var.DIVar = DIVar;
calculateRanges(Var, Entries);
recordLocalVariable(std::move(Var), Scope);
}
}
void CodeViewDebug::beginFunctionImpl(const MachineFunction *MF) {
const TargetSubtargetInfo &TSI = MF->getSubtarget();
const TargetRegisterInfo *TRI = TSI.getRegisterInfo();
const MachineFrameInfo &MFI = MF->getFrameInfo();
const Function &GV = MF->getFunction();
auto Insertion = FnDebugInfo.insert({&GV, std::make_unique<FunctionInfo>()});
assert(Insertion.second && "function already has info");
CurFn = Insertion.first->second.get();
CurFn->FuncId = NextFuncId++;
CurFn->Begin = Asm->getFunctionBegin();
// The S_FRAMEPROC record reports the stack size, and how many bytes of
// callee-saved registers were used. For targets that don't use a PUSH
// instruction (AArch64), this will be zero.
CurFn->CSRSize = MFI.getCVBytesOfCalleeSavedRegisters();
CurFn->FrameSize = MFI.getStackSize();
CurFn->OffsetAdjustment = MFI.getOffsetAdjustment();
CurFn->HasStackRealignment = TRI->hasStackRealignment(*MF);
// For this function S_FRAMEPROC record, figure out which codeview register
// will be the frame pointer.
CurFn->EncodedParamFramePtrReg = EncodedFramePtrReg::None; // None.
CurFn->EncodedLocalFramePtrReg = EncodedFramePtrReg::None; // None.
if (CurFn->FrameSize > 0) {
if (!TSI.getFrameLowering()->hasFP(*MF)) {
CurFn->EncodedLocalFramePtrReg = EncodedFramePtrReg::StackPtr;
CurFn->EncodedParamFramePtrReg = EncodedFramePtrReg::StackPtr;
} else {
CurFn->HasFramePointer = true;
// If there is an FP, parameters are always relative to it.
CurFn->EncodedParamFramePtrReg = EncodedFramePtrReg::FramePtr;
if (CurFn->HasStackRealignment) {
// If the stack needs realignment, locals are relative to SP or VFRAME.
CurFn->EncodedLocalFramePtrReg = EncodedFramePtrReg::StackPtr;
} else {
// Otherwise, locals are relative to EBP, and we probably have VLAs or
// other stack adjustments.
CurFn->EncodedLocalFramePtrReg = EncodedFramePtrReg::FramePtr;
}
}
}
// Compute other frame procedure options.
FrameProcedureOptions FPO = FrameProcedureOptions::None;
if (MFI.hasVarSizedObjects())
FPO |= FrameProcedureOptions::HasAlloca;
if (MF->exposesReturnsTwice())
FPO |= FrameProcedureOptions::HasSetJmp;
// FIXME: Set HasLongJmp if we ever track that info.
if (MF->hasInlineAsm())
FPO |= FrameProcedureOptions::HasInlineAssembly;
if (GV.hasPersonalityFn()) {
if (isAsynchronousEHPersonality(
classifyEHPersonality(GV.getPersonalityFn())))
FPO |= FrameProcedureOptions::HasStructuredExceptionHandling;
else
FPO |= FrameProcedureOptions::HasExceptionHandling;
}
if (GV.hasFnAttribute(Attribute::InlineHint))
FPO |= FrameProcedureOptions::MarkedInline;
if (GV.hasFnAttribute(Attribute::Naked))
FPO |= FrameProcedureOptions::Naked;
if (MFI.hasStackProtectorIndex()) {
FPO |= FrameProcedureOptions::SecurityChecks;
if (GV.hasFnAttribute(Attribute::StackProtectStrong) ||
GV.hasFnAttribute(Attribute::StackProtectReq)) {
FPO |= FrameProcedureOptions::StrictSecurityChecks;
}
} else if (!GV.hasStackProtectorFnAttr()) {
// __declspec(safebuffers) disables stack guards.
FPO |= FrameProcedureOptions::SafeBuffers;
}
FPO |= FrameProcedureOptions(uint32_t(CurFn->EncodedLocalFramePtrReg) << 14U);
FPO |= FrameProcedureOptions(uint32_t(CurFn->EncodedParamFramePtrReg) << 16U);
if (Asm->TM.getOptLevel() != CodeGenOptLevel::None && !GV.hasOptSize() &&
!GV.hasOptNone())
FPO |= FrameProcedureOptions::OptimizedForSpeed;
if (GV.hasProfileData()) {
FPO |= FrameProcedureOptions::ValidProfileCounts;
FPO |= FrameProcedureOptions::ProfileGuidedOptimization;
}
// FIXME: Set GuardCfg when it is implemented.
CurFn->FrameProcOpts = FPO;
OS.emitCVFuncIdDirective(CurFn->FuncId);
// Find the end of the function prolog. First known non-DBG_VALUE and
// non-frame setup location marks the beginning of the function body.
// FIXME: is there a simpler a way to do this? Can we just search
// for the first instruction of the function, not the last of the prolog?
DebugLoc PrologEndLoc;
bool EmptyPrologue = true;
for (const auto &MBB : *MF) {
for (const auto &MI : MBB) {
if (!MI.isMetaInstruction() && !MI.getFlag(MachineInstr::FrameSetup) &&
MI.getDebugLoc()) {
PrologEndLoc = MI.getDebugLoc();
break;
} else if (!MI.isMetaInstruction()) {
EmptyPrologue = false;
}
}
}
// Record beginning of function if we have a non-empty prologue.
if (PrologEndLoc && !EmptyPrologue) {
DebugLoc FnStartDL = PrologEndLoc.getFnDebugLoc();
maybeRecordLocation(FnStartDL, MF);
}
// Find heap alloc sites and emit labels around them.
for (const auto &MBB : *MF) {
for (const auto &MI : MBB) {
if (MI.getHeapAllocMarker()) {
requestLabelBeforeInsn(&MI);
requestLabelAfterInsn(&MI);
}
}
}
// Mark branches that may potentially be using jump tables with labels.
bool isThumb = MMI->getModule()->getTargetTriple().getArch() ==
llvm::Triple::ArchType::thumb;
discoverJumpTableBranches(MF, isThumb);
}
static bool shouldEmitUdt(const DIType *T) {
if (!T)
return false;
// MSVC does not emit UDTs for typedefs that are scoped to classes.
if (T->getTag() == dwarf::DW_TAG_typedef) {
if (DIScope *Scope = T->getScope()) {
switch (Scope->getTag()) {
case dwarf::DW_TAG_structure_type:
case dwarf::DW_TAG_class_type:
case dwarf::DW_TAG_union_type:
return false;
default:
// do nothing.
;
}
}
}
while (true) {
if (!T || T->isForwardDecl())
return false;
const DIDerivedType *DT = dyn_cast<DIDerivedType>(T);
if (!DT)
return true;
T = DT->getBaseType();
}
return true;
}
void CodeViewDebug::addToUDTs(const DIType *Ty) {
// Don't record empty UDTs.
if (Ty->getName().empty())
return;
if (!shouldEmitUdt(Ty))
return;
SmallVector<StringRef, 5> ParentScopeNames;
const DISubprogram *ClosestSubprogram =
collectParentScopeNames(Ty->getScope(), ParentScopeNames);
std::string FullyQualifiedName =
formatNestedName(ParentScopeNames, getPrettyScopeName(Ty));
if (ClosestSubprogram == nullptr) {
GlobalUDTs.emplace_back(std::move(FullyQualifiedName), Ty);
} else if (ClosestSubprogram == CurrentSubprogram) {
LocalUDTs.emplace_back(std::move(FullyQualifiedName), Ty);
}
// TODO: What if the ClosestSubprogram is neither null or the current
// subprogram? Currently, the UDT just gets dropped on the floor.
//
// The current behavior is not desirable. To get maximal fidelity, we would
// need to perform all type translation before beginning emission of .debug$S
// and then make LocalUDTs a member of FunctionInfo
}
TypeIndex CodeViewDebug::lowerType(const DIType *Ty, const DIType *ClassTy) {
// Generic dispatch for lowering an unknown type.
switch (Ty->getTag()) {
case dwarf::DW_TAG_array_type:
return lowerTypeArray(cast<DICompositeType>(Ty));
case dwarf::DW_TAG_typedef:
return lowerTypeAlias(cast<DIDerivedType>(Ty));
case dwarf::DW_TAG_base_type:
return lowerTypeBasic(cast<DIBasicType>(Ty));
case dwarf::DW_TAG_pointer_type:
if (cast<DIDerivedType>(Ty)->getName() == "__vtbl_ptr_type")
return lowerTypeVFTableShape(cast<DIDerivedType>(Ty));
[[fallthrough]];
case dwarf::DW_TAG_reference_type:
case dwarf::DW_TAG_rvalue_reference_type:
return lowerTypePointer(cast<DIDerivedType>(Ty));
case dwarf::DW_TAG_ptr_to_member_type:
return lowerTypeMemberPointer(cast<DIDerivedType>(Ty));
case dwarf::DW_TAG_restrict_type:
case dwarf::DW_TAG_const_type:
case dwarf::DW_TAG_volatile_type:
// TODO: add support for DW_TAG_atomic_type here
return lowerTypeModifier(cast<DIDerivedType>(Ty));
case dwarf::DW_TAG_subroutine_type:
if (ClassTy) {
// The member function type of a member function pointer has no
// ThisAdjustment.
return lowerTypeMemberFunction(cast<DISubroutineType>(Ty), ClassTy,
/*ThisAdjustment=*/0,
/*IsStaticMethod=*/false);
}
return lowerTypeFunction(cast<DISubroutineType>(Ty));
case dwarf::DW_TAG_enumeration_type:
return lowerTypeEnum(cast<DICompositeType>(Ty));
case dwarf::DW_TAG_class_type:
case dwarf::DW_TAG_structure_type:
return lowerTypeClass(cast<DICompositeType>(Ty));
case dwarf::DW_TAG_union_type:
return lowerTypeUnion(cast<DICompositeType>(Ty));
case dwarf::DW_TAG_string_type:
return lowerTypeString(cast<DIStringType>(Ty));
case dwarf::DW_TAG_unspecified_type:
if (Ty->getName() == "decltype(nullptr)")
return TypeIndex::NullptrT();
return TypeIndex::None();
default:
// Use the null type index.
return TypeIndex();
}
}
TypeIndex CodeViewDebug::lowerTypeAlias(const DIDerivedType *Ty) {
TypeIndex UnderlyingTypeIndex = getTypeIndex(Ty->getBaseType());
StringRef TypeName = Ty->getName();
addToUDTs(Ty);
if (UnderlyingTypeIndex == TypeIndex(SimpleTypeKind::Int32Long) &&
TypeName == "HRESULT")
return TypeIndex(SimpleTypeKind::HResult);
if (UnderlyingTypeIndex == TypeIndex(SimpleTypeKind::UInt16Short) &&
TypeName == "wchar_t")
return TypeIndex(SimpleTypeKind::WideCharacter);
return UnderlyingTypeIndex;
}
TypeIndex CodeViewDebug::lowerTypeArray(const DICompositeType *Ty) {
const DIType *ElementType = Ty->getBaseType();
TypeIndex ElementTypeIndex = getTypeIndex(ElementType);
// IndexType is size_t, which depends on the bitness of the target.
TypeIndex IndexType = getPointerSizeInBytes() == 8
? TypeIndex(SimpleTypeKind::UInt64Quad)
: TypeIndex(SimpleTypeKind::UInt32Long);
uint64_t ElementSize = getBaseTypeSize(ElementType) / 8;
// Add subranges to array type.
DINodeArray Elements = Ty->getElements();
for (int i = Elements.size() - 1; i >= 0; --i) {
const DINode *Element = Elements[i];
assert(Element->getTag() == dwarf::DW_TAG_subrange_type);
const DISubrange *Subrange = cast<DISubrange>(Element);
int64_t Count = -1;
// If Subrange has a Count field, use it.
// Otherwise, if it has an upperboud, use (upperbound - lowerbound + 1),
// where lowerbound is from the LowerBound field of the Subrange,
// or the language default lowerbound if that field is unspecified.
if (auto *CI = dyn_cast_if_present<ConstantInt *>(Subrange->getCount()))
Count = CI->getSExtValue();
else if (auto *UI = dyn_cast_if_present<ConstantInt *>(
Subrange->getUpperBound())) {
// Fortran uses 1 as the default lowerbound; other languages use 0.
int64_t Lowerbound = (moduleIsInFortran()) ? 1 : 0;
auto *LI = dyn_cast_if_present<ConstantInt *>(Subrange->getLowerBound());
Lowerbound = (LI) ? LI->getSExtValue() : Lowerbound;
Count = UI->getSExtValue() - Lowerbound + 1;
}
// Forward declarations of arrays without a size and VLAs use a count of -1.
// Emit a count of zero in these cases to match what MSVC does for arrays
// without a size. MSVC doesn't support VLAs, so it's not clear what we
// should do for them even if we could distinguish them.
if (Count == -1)
Count = 0;
// Update the element size and element type index for subsequent subranges.
ElementSize *= Count;
// If this is the outermost array, use the size from the array. It will be
// more accurate if we had a VLA or an incomplete element type size.
uint64_t ArraySize =
(i == 0 && ElementSize == 0) ? Ty->getSizeInBits() / 8 : ElementSize;
StringRef Name = (i == 0) ? Ty->getName() : "";
ArrayRecord AR(ElementTypeIndex, IndexType, ArraySize, Name);
ElementTypeIndex = TypeTable.writeLeafType(AR);
}
return ElementTypeIndex;
}
// This function lowers a Fortran character type (DIStringType).
// Note that it handles only the character*n variant (using SizeInBits
// field in DIString to describe the type size) at the moment.
// Other variants (leveraging the StringLength and StringLengthExp
// fields in DIStringType) remain TBD.
TypeIndex CodeViewDebug::lowerTypeString(const DIStringType *Ty) {
TypeIndex CharType = TypeIndex(SimpleTypeKind::NarrowCharacter);
uint64_t ArraySize = Ty->getSizeInBits() >> 3;
StringRef Name = Ty->getName();
// IndexType is size_t, which depends on the bitness of the target.
TypeIndex IndexType = getPointerSizeInBytes() == 8
? TypeIndex(SimpleTypeKind::UInt64Quad)
: TypeIndex(SimpleTypeKind::UInt32Long);
// Create a type of character array of ArraySize.
ArrayRecord AR(CharType, IndexType, ArraySize, Name);
return TypeTable.writeLeafType(AR);
}
TypeIndex CodeViewDebug::lowerTypeBasic(const DIBasicType *Ty) {
TypeIndex Index;
dwarf::TypeKind Kind;
uint32_t ByteSize;
Kind = static_cast<dwarf::TypeKind>(Ty->getEncoding());
ByteSize = Ty->getSizeInBits() / 8;
SimpleTypeKind STK = SimpleTypeKind::None;
switch (Kind) {
case dwarf::DW_ATE_address:
// FIXME: Translate
break;
case dwarf::DW_ATE_boolean:
switch (ByteSize) {
case 1: STK = SimpleTypeKind::Boolean8; break;
case 2: STK = SimpleTypeKind::Boolean16; break;
case 4: STK = SimpleTypeKind::Boolean32; break;
case 8: STK = SimpleTypeKind::Boolean64; break;
case 16: STK = SimpleTypeKind::Boolean128; break;
}
break;
case dwarf::DW_ATE_complex_float:
// The CodeView size for a complex represents the size of
// an individual component.
switch (ByteSize) {
case 4: STK = SimpleTypeKind::Complex16; break;
case 8: STK = SimpleTypeKind::Complex32; break;
case 16: STK = SimpleTypeKind::Complex64; break;
case 20: STK = SimpleTypeKind::Complex80; break;
case 32: STK = SimpleTypeKind::Complex128; break;
}
break;
case dwarf::DW_ATE_float:
switch (ByteSize) {
case 2: STK = SimpleTypeKind::Float16; break;
case 4: STK = SimpleTypeKind::Float32; break;
case 6: STK = SimpleTypeKind::Float48; break;
case 8: STK = SimpleTypeKind::Float64; break;
case 10: STK = SimpleTypeKind::Float80; break;
case 16: STK = SimpleTypeKind::Float128; break;
}
break;
case dwarf::DW_ATE_signed:
switch (ByteSize) {
case 1: STK = SimpleTypeKind::SignedCharacter; break;
case 2: STK = SimpleTypeKind::Int16Short; break;
case 4: STK = SimpleTypeKind::Int32; break;
case 8: STK = SimpleTypeKind::Int64Quad; break;
case 16: STK = SimpleTypeKind::Int128Oct; break;
}
break;
case dwarf::DW_ATE_unsigned:
switch (ByteSize) {
case 1: STK = SimpleTypeKind::UnsignedCharacter; break;
case 2: STK = SimpleTypeKind::UInt16Short; break;
case 4: STK = SimpleTypeKind::UInt32; break;
case 8: STK = SimpleTypeKind::UInt64Quad; break;
case 16: STK = SimpleTypeKind::UInt128Oct; break;
}
break;
case dwarf::DW_ATE_UTF:
switch (ByteSize) {
case 1: STK = SimpleTypeKind::Character8; break;
case 2: STK = SimpleTypeKind::Character16; break;
case 4: STK = SimpleTypeKind::Character32; break;
}
break;
case dwarf::DW_ATE_signed_char:
if (ByteSize == 1)
STK = SimpleTypeKind::SignedCharacter;
break;
case dwarf::DW_ATE_unsigned_char:
if (ByteSize == 1)
STK = SimpleTypeKind::UnsignedCharacter;
break;
default:
break;
}
// Apply some fixups based on the source-level type name.
// Include some amount of canonicalization from an old naming scheme Clang
// used to use for integer types (in an outdated effort to be compatible with
// GCC's debug info/GDB's behavior, which has since been addressed).
if (STK == SimpleTypeKind::Int32 &&
(Ty->getName() == "long int" || Ty->getName() == "long"))
STK = SimpleTypeKind::Int32Long;
if (STK == SimpleTypeKind::UInt32 && (Ty->getName() == "long unsigned int" ||
Ty->getName() == "unsigned long"))
STK = SimpleTypeKind::UInt32Long;
if (STK == SimpleTypeKind::UInt16Short &&
(Ty->getName() == "wchar_t" || Ty->getName() == "__wchar_t"))
STK = SimpleTypeKind::WideCharacter;
if ((STK == SimpleTypeKind::SignedCharacter ||
STK == SimpleTypeKind::UnsignedCharacter) &&
Ty->getName() == "char")
STK = SimpleTypeKind::NarrowCharacter;
return TypeIndex(STK);
}
TypeIndex CodeViewDebug::lowerTypePointer(const DIDerivedType *Ty,
PointerOptions PO) {
TypeIndex PointeeTI = getTypeIndex(Ty->getBaseType());
// Pointers to simple types without any options can use SimpleTypeMode, rather
// than having a dedicated pointer type record.
if (PointeeTI.isSimple() && PO == PointerOptions::None &&
PointeeTI.getSimpleMode() == SimpleTypeMode::Direct &&
Ty->getTag() == dwarf::DW_TAG_pointer_type) {
SimpleTypeMode Mode = Ty->getSizeInBits() == 64
? SimpleTypeMode::NearPointer64
: SimpleTypeMode::NearPointer32;
return TypeIndex(PointeeTI.getSimpleKind(), Mode);
}
PointerKind PK =
Ty->getSizeInBits() == 64 ? PointerKind::Near64 : PointerKind::Near32;
PointerMode PM = PointerMode::Pointer;
switch (Ty->getTag()) {
default: llvm_unreachable("not a pointer tag type");
case dwarf::DW_TAG_pointer_type:
PM = PointerMode::Pointer;
break;
case dwarf::DW_TAG_reference_type:
PM = PointerMode::LValueReference;
break;
case dwarf::DW_TAG_rvalue_reference_type:
PM = PointerMode::RValueReference;
break;
}
if (Ty->isObjectPointer())
PO |= PointerOptions::Const;
PointerRecord PR(PointeeTI, PK, PM, PO, Ty->getSizeInBits() / 8);
return TypeTable.writeLeafType(PR);
}
static PointerToMemberRepresentation
translatePtrToMemberRep(unsigned SizeInBytes, bool IsPMF, unsigned Flags) {
// SizeInBytes being zero generally implies that the member pointer type was
// incomplete, which can happen if it is part of a function prototype. In this
// case, use the unknown model instead of the general model.
if (IsPMF) {
switch (Flags & DINode::FlagPtrToMemberRep) {
case 0:
return SizeInBytes == 0 ? PointerToMemberRepresentation::Unknown
: PointerToMemberRepresentation::GeneralFunction;
case DINode::FlagSingleInheritance:
return PointerToMemberRepresentation::SingleInheritanceFunction;
case DINode::FlagMultipleInheritance:
return PointerToMemberRepresentation::MultipleInheritanceFunction;
case DINode::FlagVirtualInheritance:
return PointerToMemberRepresentation::VirtualInheritanceFunction;
}
} else {
switch (Flags & DINode::FlagPtrToMemberRep) {
case 0:
return SizeInBytes == 0 ? PointerToMemberRepresentation::Unknown
: PointerToMemberRepresentation::GeneralData;
case DINode::FlagSingleInheritance:
return PointerToMemberRepresentation::SingleInheritanceData;
case DINode::FlagMultipleInheritance:
return PointerToMemberRepresentation::MultipleInheritanceData;
case DINode::FlagVirtualInheritance:
return PointerToMemberRepresentation::VirtualInheritanceData;
}
}
llvm_unreachable("invalid ptr to member representation");
}
TypeIndex CodeViewDebug::lowerTypeMemberPointer(const DIDerivedType *Ty,
PointerOptions PO) {
assert(Ty->getTag() == dwarf::DW_TAG_ptr_to_member_type);
bool IsPMF = isa<DISubroutineType>(Ty->getBaseType());
TypeIndex ClassTI = getTypeIndex(Ty->getClassType());
TypeIndex PointeeTI =
getTypeIndex(Ty->getBaseType(), IsPMF ? Ty->getClassType() : nullptr);
PointerKind PK = getPointerSizeInBytes() == 8 ? PointerKind::Near64
: PointerKind::Near32;
PointerMode PM = IsPMF ? PointerMode::PointerToMemberFunction
: PointerMode::PointerToDataMember;
assert(Ty->getSizeInBits() / 8 <= 0xff && "pointer size too big");
uint8_t SizeInBytes = Ty->getSizeInBits() / 8;
MemberPointerInfo MPI(
ClassTI, translatePtrToMemberRep(SizeInBytes, IsPMF, Ty->getFlags()));
PointerRecord PR(PointeeTI, PK, PM, PO, SizeInBytes, MPI);
return TypeTable.writeLeafType(PR);
}
/// Given a DWARF calling convention, get the CodeView equivalent. If we don't
/// have a translation, use the NearC convention.
static CallingConvention dwarfCCToCodeView(unsigned DwarfCC) {
switch (DwarfCC) {
case dwarf::DW_CC_normal: return CallingConvention::NearC;
case dwarf::DW_CC_BORLAND_msfastcall: return CallingConvention::NearFast;
case dwarf::DW_CC_BORLAND_thiscall: return CallingConvention::ThisCall;
case dwarf::DW_CC_BORLAND_stdcall: return CallingConvention::NearStdCall;
case dwarf::DW_CC_BORLAND_pascal: return CallingConvention::NearPascal;
case dwarf::DW_CC_LLVM_vectorcall: return CallingConvention::NearVector;
}
return CallingConvention::NearC;
}
TypeIndex CodeViewDebug::lowerTypeModifier(const DIDerivedType *Ty) {
ModifierOptions Mods = ModifierOptions::None;
PointerOptions PO = PointerOptions::None;
bool IsModifier = true;
const DIType *BaseTy = Ty;
while (IsModifier && BaseTy) {
// FIXME: Need to add DWARF tags for __unaligned and _Atomic
switch (BaseTy->getTag()) {
case dwarf::DW_TAG_const_type:
Mods |= ModifierOptions::Const;
PO |= PointerOptions::Const;
break;
case dwarf::DW_TAG_volatile_type:
Mods |= ModifierOptions::Volatile;
PO |= PointerOptions::Volatile;
break;
case dwarf::DW_TAG_restrict_type:
// Only pointer types be marked with __restrict. There is no known flag
// for __restrict in LF_MODIFIER records.
PO |= PointerOptions::Restrict;
break;
default:
IsModifier = false;
break;
}
if (IsModifier)
BaseTy = cast<DIDerivedType>(BaseTy)->getBaseType();
}
// Check if the inner type will use an LF_POINTER record. If so, the
// qualifiers will go in the LF_POINTER record. This comes up for types like
// 'int *const' and 'int *__restrict', not the more common cases like 'const
// char *'.
if (BaseTy) {
switch (BaseTy->getTag()) {
case dwarf::DW_TAG_pointer_type:
case dwarf::DW_TAG_reference_type:
case dwarf::DW_TAG_rvalue_reference_type:
return lowerTypePointer(cast<DIDerivedType>(BaseTy), PO);
case dwarf::DW_TAG_ptr_to_member_type:
return lowerTypeMemberPointer(cast<DIDerivedType>(BaseTy), PO);
default:
break;
}
}
TypeIndex ModifiedTI = getTypeIndex(BaseTy);
// Return the base type index if there aren't any modifiers. For example, the
// metadata could contain restrict wrappers around non-pointer types.
if (Mods == ModifierOptions::None)
return ModifiedTI;
ModifierRecord MR(ModifiedTI, Mods);
return TypeTable.writeLeafType(MR);
}
TypeIndex CodeViewDebug::lowerTypeFunction(const DISubroutineType *Ty) {
SmallVector<TypeIndex, 8> ReturnAndArgTypeIndices;
for (const DIType *ArgType : Ty->getTypeArray())
ReturnAndArgTypeIndices.push_back(getTypeIndex(ArgType));
// MSVC uses type none for variadic argument.
if (ReturnAndArgTypeIndices.size() > 1 &&
ReturnAndArgTypeIndices.back() == TypeIndex::Void()) {
ReturnAndArgTypeIndices.back() = TypeIndex::None();
}
TypeIndex ReturnTypeIndex = TypeIndex::Void();
ArrayRef<TypeIndex> ArgTypeIndices = {};
if (!ReturnAndArgTypeIndices.empty()) {
auto ReturnAndArgTypesRef = ArrayRef(ReturnAndArgTypeIndices);
ReturnTypeIndex = ReturnAndArgTypesRef.front();
ArgTypeIndices = ReturnAndArgTypesRef.drop_front();
}
ArgListRecord ArgListRec(TypeRecordKind::ArgList, ArgTypeIndices);
TypeIndex ArgListIndex = TypeTable.writeLeafType(ArgListRec);
CallingConvention CC = dwarfCCToCodeView(Ty->getCC());
FunctionOptions FO = getFunctionOptions(Ty);
ProcedureRecord Procedure(ReturnTypeIndex, CC, FO, ArgTypeIndices.size(),
ArgListIndex);
return TypeTable.writeLeafType(Procedure);
}
TypeIndex CodeViewDebug::lowerTypeMemberFunction(const DISubroutineType *Ty,
const DIType *ClassTy,
int ThisAdjustment,
bool IsStaticMethod,
FunctionOptions FO) {
// Lower the containing class type.
TypeIndex ClassType = getTypeIndex(ClassTy);
DITypeRefArray ReturnAndArgs = Ty->getTypeArray();
unsigned Index = 0;
SmallVector<TypeIndex, 8> ArgTypeIndices;
TypeIndex ReturnTypeIndex = TypeIndex::Void();
if (ReturnAndArgs.size() > Index) {
ReturnTypeIndex = getTypeIndex(ReturnAndArgs[Index++]);
}
// If the first argument is a pointer type and this isn't a static method,
// treat it as the special 'this' parameter, which is encoded separately from
// the arguments.
TypeIndex ThisTypeIndex;
if (!IsStaticMethod && ReturnAndArgs.size() > Index) {
if (const DIDerivedType *PtrTy =
dyn_cast_or_null<DIDerivedType>(ReturnAndArgs[Index])) {
if (PtrTy->getTag() == dwarf::DW_TAG_pointer_type) {
ThisTypeIndex = getTypeIndexForThisPtr(PtrTy, Ty);
Index++;
}
}
}
while (Index < ReturnAndArgs.size())
ArgTypeIndices.push_back(getTypeIndex(ReturnAndArgs[Index++]));
// MSVC uses type none for variadic argument.
if (!ArgTypeIndices.empty() && ArgTypeIndices.back() == TypeIndex::Void())
ArgTypeIndices.back() = TypeIndex::None();
ArgListRecord ArgListRec(TypeRecordKind::ArgList, ArgTypeIndices);
TypeIndex ArgListIndex = TypeTable.writeLeafType(ArgListRec);
CallingConvention CC = dwarfCCToCodeView(Ty->getCC());
MemberFunctionRecord MFR(ReturnTypeIndex, ClassType, ThisTypeIndex, CC, FO,
ArgTypeIndices.size(), ArgListIndex, ThisAdjustment);
return TypeTable.writeLeafType(MFR);
}
TypeIndex CodeViewDebug::lowerTypeVFTableShape(const DIDerivedType *Ty) {
unsigned VSlotCount =
Ty->getSizeInBits() / (8 * Asm->MAI->getCodePointerSize());
SmallVector<VFTableSlotKind, 4> Slots(VSlotCount, VFTableSlotKind::Near);
VFTableShapeRecord VFTSR(Slots);
return TypeTable.writeLeafType(VFTSR);
}
static MemberAccess translateAccessFlags(unsigned RecordTag, unsigned Flags) {
switch (Flags & DINode::FlagAccessibility) {
case DINode::FlagPrivate: return MemberAccess::Private;
case DINode::FlagPublic: return MemberAccess::Public;
case DINode::FlagProtected: return MemberAccess::Protected;
case 0:
// If there was no explicit access control, provide the default for the tag.
return RecordTag == dwarf::DW_TAG_class_type ? MemberAccess::Private
: MemberAccess::Public;
}
llvm_unreachable("access flags are exclusive");
}
static MethodOptions translateMethodOptionFlags(const DISubprogram *SP) {
if (SP->isArtificial())
return MethodOptions::CompilerGenerated;
// FIXME: Handle other MethodOptions.
return MethodOptions::None;
}
static MethodKind translateMethodKindFlags(const DISubprogram *SP,
bool Introduced) {
if (SP->getFlags() & DINode::FlagStaticMember)
return MethodKind::Static;
switch (SP->getVirtuality()) {
case dwarf::DW_VIRTUALITY_none:
break;
case dwarf::DW_VIRTUALITY_virtual:
return Introduced ? MethodKind::IntroducingVirtual : MethodKind::Virtual;
case dwarf::DW_VIRTUALITY_pure_virtual:
return Introduced ? MethodKind::PureIntroducingVirtual
: MethodKind::PureVirtual;
default:
llvm_unreachable("unhandled virtuality case");
}
return MethodKind::Vanilla;
}
static TypeRecordKind getRecordKind(const DICompositeType *Ty) {
switch (Ty->getTag()) {
case dwarf::DW_TAG_class_type:
return TypeRecordKind::Class;
case dwarf::DW_TAG_structure_type:
return TypeRecordKind::Struct;
default:
llvm_unreachable("unexpected tag");
}
}
/// Return ClassOptions that should be present on both the forward declaration
/// and the defintion of a tag type.
static ClassOptions getCommonClassOptions(const DICompositeType *Ty) {
ClassOptions CO = ClassOptions::None;
// MSVC always sets this flag, even for local types. Clang doesn't always
// appear to give every type a linkage name, which may be problematic for us.
// FIXME: Investigate the consequences of not following them here.
if (!Ty->getIdentifier().empty())
CO |= ClassOptions::HasUniqueName;
// Put the Nested flag on a type if it appears immediately inside a tag type.
// Do not walk the scope chain. Do not attempt to compute ContainsNestedClass
// here. That flag is only set on definitions, and not forward declarations.
const DIScope *ImmediateScope = Ty->getScope();
if (ImmediateScope && isa<DICompositeType>(ImmediateScope))
CO |= ClassOptions::Nested;
// Put the Scoped flag on function-local types. MSVC puts this flag for enum
// type only when it has an immediate function scope. Clang never puts enums
// inside DILexicalBlock scopes. Enum types, as generated by clang, are
// always in function, class, or file scopes.
if (Ty->getTag() == dwarf::DW_TAG_enumeration_type) {
if (ImmediateScope && isa<DISubprogram>(ImmediateScope))
CO |= ClassOptions::Scoped;
} else {
for (const DIScope *Scope = ImmediateScope; Scope != nullptr;
Scope = Scope->getScope()) {
if (isa<DISubprogram>(Scope)) {
CO |= ClassOptions::Scoped;
break;
}
}
}
return CO;
}
void CodeViewDebug::addUDTSrcLine(const DIType *Ty, TypeIndex TI) {
switch (Ty->getTag()) {
case dwarf::DW_TAG_class_type:
case dwarf::DW_TAG_structure_type:
case dwarf::DW_TAG_union_type:
case dwarf::DW_TAG_enumeration_type:
break;
default:
return;
}
if (const auto *File = Ty->getFile()) {
StringIdRecord SIDR(TypeIndex(0x0), getFullFilepath(File));
TypeIndex SIDI = TypeTable.writeLeafType(SIDR);
UdtSourceLineRecord USLR(TI, SIDI, Ty->getLine());
TypeTable.writeLeafType(USLR);
}
}
TypeIndex CodeViewDebug::lowerTypeEnum(const DICompositeType *Ty) {
ClassOptions CO = getCommonClassOptions(Ty);
TypeIndex FTI;
unsigned EnumeratorCount = 0;
if (Ty->isForwardDecl()) {
CO |= ClassOptions::ForwardReference;
} else {
ContinuationRecordBuilder ContinuationBuilder;
ContinuationBuilder.begin(ContinuationRecordKind::FieldList);
for (const DINode *Element : Ty->getElements()) {
// We assume that the frontend provides all members in source declaration
// order, which is what MSVC does.
if (auto *Enumerator = dyn_cast_or_null<DIEnumerator>(Element)) {
// FIXME: Is it correct to always emit these as unsigned here?
EnumeratorRecord ER(MemberAccess::Public,
APSInt(Enumerator->getValue(), true),
Enumerator->getName());
ContinuationBuilder.writeMemberType(ER);
EnumeratorCount++;
}
}
FTI = TypeTable.insertRecord(ContinuationBuilder);
}
std::string FullName = getFullyQualifiedName(Ty);
EnumRecord ER(EnumeratorCount, CO, FTI, FullName, Ty->getIdentifier(),
getTypeIndex(Ty->getBaseType()));
TypeIndex EnumTI = TypeTable.writeLeafType(ER);
addUDTSrcLine(Ty, EnumTI);
return EnumTI;
}
//===----------------------------------------------------------------------===//
// ClassInfo
//===----------------------------------------------------------------------===//
struct llvm::ClassInfo {
struct MemberInfo {
const DIDerivedType *MemberTypeNode;
uint64_t BaseOffset;
};
// [MemberInfo]
using MemberList = std::vector<MemberInfo>;
using MethodsList = TinyPtrVector<const DISubprogram *>;
// MethodName -> MethodsList
using MethodsMap = MapVector<MDString *, MethodsList>;
/// Base classes.
std::vector<const DIDerivedType *> Inheritance;
/// Direct members.
MemberList Members;
// Direct overloaded methods gathered by name.
MethodsMap Methods;
TypeIndex VShapeTI;
std::vector<const DIType *> NestedTypes;
};
void CodeViewDebug::clear() {
assert(CurFn == nullptr);
FileIdMap.clear();
FnDebugInfo.clear();
FileToFilepathMap.clear();
LocalUDTs.clear();
GlobalUDTs.clear();
TypeIndices.clear();
CompleteTypeIndices.clear();
ScopeGlobals.clear();
CVGlobalVariableOffsets.clear();
}
void CodeViewDebug::collectMemberInfo(ClassInfo &Info,
const DIDerivedType *DDTy) {
if (!DDTy->getName().empty()) {
Info.Members.push_back({DDTy, 0});
// Collect static const data members with values.
if ((DDTy->getFlags() & DINode::FlagStaticMember) ==
DINode::FlagStaticMember) {
if (DDTy->getConstant() && (isa<ConstantInt>(DDTy->getConstant()) ||
isa<ConstantFP>(DDTy->getConstant())))
StaticConstMembers.push_back(DDTy);
}
return;
}
// An unnamed member may represent a nested struct or union. Attempt to
// interpret the unnamed member as a DICompositeType possibly wrapped in
// qualifier types. Add all the indirect fields to the current record if that
// succeeds, and drop the member if that fails.
assert((DDTy->getOffsetInBits() % 8) == 0 && "Unnamed bitfield member!");
uint64_t Offset = DDTy->getOffsetInBits();
const DIType *Ty = DDTy->getBaseType();
bool FullyResolved = false;
while (!FullyResolved) {
switch (Ty->getTag()) {
case dwarf::DW_TAG_const_type:
case dwarf::DW_TAG_volatile_type:
// FIXME: we should apply the qualifier types to the indirect fields
// rather than dropping them.
Ty = cast<DIDerivedType>(Ty)->getBaseType();
break;
default:
FullyResolved = true;
break;
}
}
const DICompositeType *DCTy = dyn_cast<DICompositeType>(Ty);
if (!DCTy)
return;
ClassInfo NestedInfo = collectClassInfo(DCTy);
for (const ClassInfo::MemberInfo &IndirectField : NestedInfo.Members)
Info.Members.push_back(
{IndirectField.MemberTypeNode, IndirectField.BaseOffset + Offset});
}
ClassInfo CodeViewDebug::collectClassInfo(const DICompositeType *Ty) {
ClassInfo Info;
// Add elements to structure type.
DINodeArray Elements = Ty->getElements();
for (auto *Element : Elements) {
// We assume that the frontend provides all members in source declaration
// order, which is what MSVC does.
if (!Element)
continue;
if (auto *SP = dyn_cast<DISubprogram>(Element)) {
Info.Methods[SP->getRawName()].push_back(SP);
} else if (auto *DDTy = dyn_cast<DIDerivedType>(Element)) {
if (DDTy->getTag() == dwarf::DW_TAG_member) {
collectMemberInfo(Info, DDTy);
} else if (DDTy->getTag() == dwarf::DW_TAG_inheritance) {
Info.Inheritance.push_back(DDTy);
} else if (DDTy->getTag() == dwarf::DW_TAG_pointer_type &&
DDTy->getName() == "__vtbl_ptr_type") {
Info.VShapeTI = getTypeIndex(DDTy);
} else if (DDTy->getTag() == dwarf::DW_TAG_typedef) {
Info.NestedTypes.push_back(DDTy);
} else if (DDTy->getTag() == dwarf::DW_TAG_friend) {
// Ignore friend members. It appears that MSVC emitted info about
// friends in the past, but modern versions do not.
}
} else if (auto *Composite = dyn_cast<DICompositeType>(Element)) {
Info.NestedTypes.push_back(Composite);
}
// Skip other unrecognized kinds of elements.
}
return Info;
}
static bool shouldAlwaysEmitCompleteClassType(const DICompositeType *Ty) {
// This routine is used by lowerTypeClass and lowerTypeUnion to determine
// if a complete type should be emitted instead of a forward reference.
return Ty->getName().empty() && Ty->getIdentifier().empty() &&
!Ty->isForwardDecl();
}
TypeIndex CodeViewDebug::lowerTypeClass(const DICompositeType *Ty) {
// Emit the complete type for unnamed structs. C++ classes with methods
// which have a circular reference back to the class type are expected to
// be named by the front-end and should not be "unnamed". C unnamed
// structs should not have circular references.
if (shouldAlwaysEmitCompleteClassType(Ty)) {
// If this unnamed complete type is already in the process of being defined
// then the description of the type is malformed and cannot be emitted
// into CodeView correctly so report a fatal error.
auto I = CompleteTypeIndices.find(Ty);
if (I != CompleteTypeIndices.end() && I->second == TypeIndex())
report_fatal_error("cannot debug circular reference to unnamed type");
return getCompleteTypeIndex(Ty);
}
// First, construct the forward decl. Don't look into Ty to compute the
// forward decl options, since it might not be available in all TUs.
TypeRecordKind Kind = getRecordKind(Ty);
ClassOptions CO =
ClassOptions::ForwardReference | getCommonClassOptions(Ty);
std::string FullName = getFullyQualifiedName(Ty);
ClassRecord CR(Kind, 0, CO, TypeIndex(), TypeIndex(), TypeIndex(), 0,
FullName, Ty->getIdentifier());
TypeIndex FwdDeclTI = TypeTable.writeLeafType(CR);
if (!Ty->isForwardDecl())
DeferredCompleteTypes.push_back(Ty);
return FwdDeclTI;
}
TypeIndex CodeViewDebug::lowerCompleteTypeClass(const DICompositeType *Ty) {
// Construct the field list and complete type record.
TypeRecordKind Kind = getRecordKind(Ty);
ClassOptions CO = getCommonClassOptions(Ty);
TypeIndex FieldTI;
TypeIndex VShapeTI;
unsigned FieldCount;
bool ContainsNestedClass;
std::tie(FieldTI, VShapeTI, FieldCount, ContainsNestedClass) =
lowerRecordFieldList(Ty);
if (ContainsNestedClass)
CO |= ClassOptions::ContainsNestedClass;
// MSVC appears to set this flag by searching any destructor or method with
// FunctionOptions::Constructor among the emitted members. Clang AST has all
// the members, however special member functions are not yet emitted into
// debug information. For now checking a class's non-triviality seems enough.
// FIXME: not true for a nested unnamed struct.
if (isNonTrivial(Ty))
CO |= ClassOptions::HasConstructorOrDestructor;
std::string FullName = getFullyQualifiedName(Ty);
uint64_t SizeInBytes = Ty->getSizeInBits() / 8;
ClassRecord CR(Kind, FieldCount, CO, FieldTI, TypeIndex(), VShapeTI,
SizeInBytes, FullName, Ty->getIdentifier());
TypeIndex ClassTI = TypeTable.writeLeafType(CR);
addUDTSrcLine(Ty, ClassTI);
addToUDTs(Ty);
return ClassTI;
}
TypeIndex CodeViewDebug::lowerTypeUnion(const DICompositeType *Ty) {
// Emit the complete type for unnamed unions.
if (shouldAlwaysEmitCompleteClassType(Ty))
return getCompleteTypeIndex(Ty);
ClassOptions CO =
ClassOptions::ForwardReference | getCommonClassOptions(Ty);
std::string FullName = getFullyQualifiedName(Ty);
UnionRecord UR(0, CO, TypeIndex(), 0, FullName, Ty->getIdentifier());
TypeIndex FwdDeclTI = TypeTable.writeLeafType(UR);
if (!Ty->isForwardDecl())
DeferredCompleteTypes.push_back(Ty);
return FwdDeclTI;
}
TypeIndex CodeViewDebug::lowerCompleteTypeUnion(const DICompositeType *Ty) {
ClassOptions CO = ClassOptions::Sealed | getCommonClassOptions(Ty);
TypeIndex FieldTI;
unsigned FieldCount;
bool ContainsNestedClass;
std::tie(FieldTI, std::ignore, FieldCount, ContainsNestedClass) =
lowerRecordFieldList(Ty);
if (ContainsNestedClass)
CO |= ClassOptions::ContainsNestedClass;
uint64_t SizeInBytes = Ty->getSizeInBits() / 8;
std::string FullName = getFullyQualifiedName(Ty);
UnionRecord UR(FieldCount, CO, FieldTI, SizeInBytes, FullName,
Ty->getIdentifier());
TypeIndex UnionTI = TypeTable.writeLeafType(UR);
addUDTSrcLine(Ty, UnionTI);
addToUDTs(Ty);
return UnionTI;
}
std::tuple<TypeIndex, TypeIndex, unsigned, bool>
CodeViewDebug::lowerRecordFieldList(const DICompositeType *Ty) {
// Manually count members. MSVC appears to count everything that generates a
// field list record. Each individual overload in a method overload group
// contributes to this count, even though the overload group is a single field
// list record.
unsigned MemberCount = 0;
ClassInfo Info = collectClassInfo(Ty);
ContinuationRecordBuilder ContinuationBuilder;
ContinuationBuilder.begin(ContinuationRecordKind::FieldList);
// Create base classes.
for (const DIDerivedType *I : Info.Inheritance) {
if (I->getFlags() & DINode::FlagVirtual) {
// Virtual base.
unsigned VBPtrOffset = I->getVBPtrOffset();
// FIXME: Despite the accessor name, the offset is really in bytes.
unsigned VBTableIndex = I->getOffsetInBits() / 4;
auto RecordKind = (I->getFlags() & DINode::FlagIndirectVirtualBase) == DINode::FlagIndirectVirtualBase
? TypeRecordKind::IndirectVirtualBaseClass
: TypeRecordKind::VirtualBaseClass;
VirtualBaseClassRecord VBCR(
RecordKind, translateAccessFlags(Ty->getTag(), I->getFlags()),
getTypeIndex(I->getBaseType()), getVBPTypeIndex(), VBPtrOffset,
VBTableIndex);
ContinuationBuilder.writeMemberType(VBCR);
MemberCount++;
} else {
assert(I->getOffsetInBits() % 8 == 0 &&
"bases must be on byte boundaries");
BaseClassRecord BCR(translateAccessFlags(Ty->getTag(), I->getFlags()),
getTypeIndex(I->getBaseType()),
I->getOffsetInBits() / 8);
ContinuationBuilder.writeMemberType(BCR);
MemberCount++;
}
}
// Create members.
for (ClassInfo::MemberInfo &MemberInfo : Info.Members) {
const DIDerivedType *Member = MemberInfo.MemberTypeNode;
TypeIndex MemberBaseType = getTypeIndex(Member->getBaseType());
StringRef MemberName = Member->getName();
MemberAccess Access =
translateAccessFlags(Ty->getTag(), Member->getFlags());
if (Member->isStaticMember()) {
StaticDataMemberRecord SDMR(Access, MemberBaseType, MemberName);
ContinuationBuilder.writeMemberType(SDMR);
MemberCount++;
continue;
}
// Virtual function pointer member.
if ((Member->getFlags() & DINode::FlagArtificial) &&
Member->getName().starts_with("_vptr$")) {
VFPtrRecord VFPR(getTypeIndex(Member->getBaseType()));
ContinuationBuilder.writeMemberType(VFPR);
MemberCount++;
continue;
}
// Data member.
uint64_t MemberOffsetInBits =
Member->getOffsetInBits() + MemberInfo.BaseOffset;
if (Member->isBitField()) {
uint64_t StartBitOffset = MemberOffsetInBits;
if (const auto *CI =
dyn_cast_or_null<ConstantInt>(Member->getStorageOffsetInBits())) {
MemberOffsetInBits = CI->getZExtValue() + MemberInfo.BaseOffset;
}
StartBitOffset -= MemberOffsetInBits;
BitFieldRecord BFR(MemberBaseType, Member->getSizeInBits(),
StartBitOffset);
MemberBaseType = TypeTable.writeLeafType(BFR);
}
uint64_t MemberOffsetInBytes = MemberOffsetInBits / 8;
DataMemberRecord DMR(Access, MemberBaseType, MemberOffsetInBytes,
MemberName);
ContinuationBuilder.writeMemberType(DMR);
MemberCount++;
}
// Create methods
for (auto &MethodItr : Info.Methods) {
StringRef Name = MethodItr.first->getString();
std::vector<OneMethodRecord> Methods;
for (const DISubprogram *SP : MethodItr.second) {
TypeIndex MethodType = getMemberFunctionType(SP, Ty);
bool Introduced = SP->getFlags() & DINode::FlagIntroducedVirtual;
unsigned VFTableOffset = -1;
if (Introduced)
VFTableOffset = SP->getVirtualIndex() * getPointerSizeInBytes();
Methods.push_back(OneMethodRecord(
MethodType, translateAccessFlags(Ty->getTag(), SP->getFlags()),
translateMethodKindFlags(SP, Introduced),
translateMethodOptionFlags(SP), VFTableOffset, Name));
MemberCount++;
}
assert(!Methods.empty() && "Empty methods map entry");
if (Methods.size() == 1)
ContinuationBuilder.writeMemberType(Methods[0]);
else {
// FIXME: Make this use its own ContinuationBuilder so that
// MethodOverloadList can be split correctly.
MethodOverloadListRecord MOLR(Methods);
TypeIndex MethodList = TypeTable.writeLeafType(MOLR);
OverloadedMethodRecord OMR(Methods.size(), MethodList, Name);
ContinuationBuilder.writeMemberType(OMR);
}
}
// Create nested classes.
for (const DIType *Nested : Info.NestedTypes) {
NestedTypeRecord R(getTypeIndex(Nested), Nested->getName());
ContinuationBuilder.writeMemberType(R);
MemberCount++;
}
TypeIndex FieldTI = TypeTable.insertRecord(ContinuationBuilder);
return std::make_tuple(FieldTI, Info.VShapeTI, MemberCount,
!Info.NestedTypes.empty());
}
TypeIndex CodeViewDebug::getVBPTypeIndex() {
if (!VBPType.getIndex()) {
// Make a 'const int *' type.
ModifierRecord MR(TypeIndex::Int32(), ModifierOptions::Const);
TypeIndex ModifiedTI = TypeTable.writeLeafType(MR);
PointerKind PK = getPointerSizeInBytes() == 8 ? PointerKind::Near64
: PointerKind::Near32;
PointerMode PM = PointerMode::Pointer;
PointerOptions PO = PointerOptions::None;
PointerRecord PR(ModifiedTI, PK, PM, PO, getPointerSizeInBytes());
VBPType = TypeTable.writeLeafType(PR);
}
return VBPType;
}
TypeIndex CodeViewDebug::getTypeIndex(const DIType *Ty, const DIType *ClassTy) {
// The null DIType is the void type. Don't try to hash it.
if (!Ty)
return TypeIndex::Void();
// Check if we've already translated this type. Don't try to do a
// get-or-create style insertion that caches the hash lookup across the
// lowerType call. It will update the TypeIndices map.
auto I = TypeIndices.find({Ty, ClassTy});
if (I != TypeIndices.end())
return I->second;
TypeLoweringScope S(*this);
TypeIndex TI = lowerType(Ty, ClassTy);
return recordTypeIndexForDINode(Ty, TI, ClassTy);
}
codeview::TypeIndex
CodeViewDebug::getTypeIndexForThisPtr(const DIDerivedType *PtrTy,
const DISubroutineType *SubroutineTy) {
assert(PtrTy->getTag() == dwarf::DW_TAG_pointer_type &&
"this type must be a pointer type");
PointerOptions Options = PointerOptions::None;
if (SubroutineTy->getFlags() & DINode::DIFlags::FlagLValueReference)
Options = PointerOptions::LValueRefThisPointer;
else if (SubroutineTy->getFlags() & DINode::DIFlags::FlagRValueReference)
Options = PointerOptions::RValueRefThisPointer;
// Check if we've already translated this type. If there is no ref qualifier
// on the function then we look up this pointer type with no associated class
// so that the TypeIndex for the this pointer can be shared with the type
// index for other pointers to this class type. If there is a ref qualifier
// then we lookup the pointer using the subroutine as the parent type.
auto I = TypeIndices.find({PtrTy, SubroutineTy});
if (I != TypeIndices.end())
return I->second;
TypeLoweringScope S(*this);
TypeIndex TI = lowerTypePointer(PtrTy, Options);
return recordTypeIndexForDINode(PtrTy, TI, SubroutineTy);
}
TypeIndex CodeViewDebug::getTypeIndexForReferenceTo(const DIType *Ty) {
PointerRecord PR(getTypeIndex(Ty),
getPointerSizeInBytes() == 8 ? PointerKind::Near64
: PointerKind::Near32,
PointerMode::LValueReference, PointerOptions::None,
Ty->getSizeInBits() / 8);
return TypeTable.writeLeafType(PR);
}
TypeIndex CodeViewDebug::getCompleteTypeIndex(const DIType *Ty) {
// The null DIType is the void type. Don't try to hash it.
if (!Ty)
return TypeIndex::Void();
// Look through typedefs when getting the complete type index. Call
// getTypeIndex on the typdef to ensure that any UDTs are accumulated and are
// emitted only once.
if (Ty->getTag() == dwarf::DW_TAG_typedef)
(void)getTypeIndex(Ty);
while (Ty->getTag() == dwarf::DW_TAG_typedef)
Ty = cast<DIDerivedType>(Ty)->getBaseType();
// If this is a non-record type, the complete type index is the same as the
// normal type index. Just call getTypeIndex.
switch (Ty->getTag()) {
case dwarf::DW_TAG_class_type:
case dwarf::DW_TAG_structure_type:
case dwarf::DW_TAG_union_type:
break;
default:
return getTypeIndex(Ty);
}
const auto *CTy = cast<DICompositeType>(Ty);
TypeLoweringScope S(*this);
// Make sure the forward declaration is emitted first. It's unclear if this
// is necessary, but MSVC does it, and we should follow suit until we can show
// otherwise.
// We only emit a forward declaration for named types.
if (!CTy->getName().empty() || !CTy->getIdentifier().empty()) {
TypeIndex FwdDeclTI = getTypeIndex(CTy);
// Just use the forward decl if we don't have complete type info. This
// might happen if the frontend is using modules and expects the complete
// definition to be emitted elsewhere.
if (CTy->isForwardDecl())
return FwdDeclTI;
}
// Check if we've already translated the complete record type.
// Insert the type with a null TypeIndex to signify that the type is currently
// being lowered.
auto InsertResult = CompleteTypeIndices.insert({CTy, TypeIndex()});
if (!InsertResult.second)
return InsertResult.first->second;
TypeIndex TI;
switch (CTy->getTag()) {
case dwarf::DW_TAG_class_type:
case dwarf::DW_TAG_structure_type:
TI = lowerCompleteTypeClass(CTy);
break;
case dwarf::DW_TAG_union_type:
TI = lowerCompleteTypeUnion(CTy);
break;
default:
llvm_unreachable("not a record");
}
// Update the type index associated with this CompositeType. This cannot
// use the 'InsertResult' iterator above because it is potentially
// invalidated by map insertions which can occur while lowering the class
// type above.
CompleteTypeIndices[CTy] = TI;
return TI;
}
/// Emit all the deferred complete record types. Try to do this in FIFO order,
/// and do this until fixpoint, as each complete record type typically
/// references
/// many other record types.
void CodeViewDebug::emitDeferredCompleteTypes() {
SmallVector<const DICompositeType *, 4> TypesToEmit;
while (!DeferredCompleteTypes.empty()) {
std::swap(DeferredCompleteTypes, TypesToEmit);
for (const DICompositeType *RecordTy : TypesToEmit)
getCompleteTypeIndex(RecordTy);
TypesToEmit.clear();
}
}
void CodeViewDebug::emitLocalVariableList(const FunctionInfo &FI,
ArrayRef<LocalVariable> Locals) {
// Get the sorted list of parameters and emit them first.
SmallVector<const LocalVariable *, 6> Params;
for (const LocalVariable &L : Locals)
if (L.DIVar->isParameter())
Params.push_back(&L);
llvm::sort(Params, [](const LocalVariable *L, const LocalVariable *R) {
return L->DIVar->getArg() < R->DIVar->getArg();
});
for (const LocalVariable *L : Params)
emitLocalVariable(FI, *L);
// Next emit all non-parameters in the order that we found them.
for (const LocalVariable &L : Locals) {
if (!L.DIVar->isParameter()) {
if (L.ConstantValue) {
// If ConstantValue is set we will emit it as a S_CONSTANT instead of a
// S_LOCAL in order to be able to represent it at all.
const DIType *Ty = L.DIVar->getType();
APSInt Val(*L.ConstantValue);
emitConstantSymbolRecord(Ty, Val, std::string(L.DIVar->getName()));
} else {
emitLocalVariable(FI, L);
}
}
}
}
void CodeViewDebug::emitLocalVariable(const FunctionInfo &FI,
const LocalVariable &Var) {
// LocalSym record, see SymbolRecord.h for more info.
MCSymbol *LocalEnd = beginSymbolRecord(SymbolKind::S_LOCAL);
LocalSymFlags Flags = LocalSymFlags::None;
if (Var.DIVar->isParameter())
Flags |= LocalSymFlags::IsParameter;
if (Var.DefRanges.empty())
Flags |= LocalSymFlags::IsOptimizedOut;
OS.AddComment("TypeIndex");
TypeIndex TI = Var.UseReferenceType
? getTypeIndexForReferenceTo(Var.DIVar->getType())
: getCompleteTypeIndex(Var.DIVar->getType());
OS.emitInt32(TI.getIndex());
OS.AddComment("Flags");
OS.emitInt16(static_cast<uint16_t>(Flags));
// Truncate the name so we won't overflow the record length field.
emitNullTerminatedSymbolName(OS, Var.DIVar->getName());
endSymbolRecord(LocalEnd);
// Calculate the on disk prefix of the appropriate def range record. The
// records and on disk formats are described in SymbolRecords.h. BytePrefix
// should be big enough to hold all forms without memory allocation.
SmallString<20> BytePrefix;
for (const auto &Pair : Var.DefRanges) {
LocalVarDef DefRange = Pair.first;
const auto &Ranges = Pair.second;
BytePrefix.clear();
if (DefRange.InMemory) {
int Offset = DefRange.DataOffset;
unsigned Reg = DefRange.CVRegister;
// 32-bit x86 call sequences often use PUSH instructions, which disrupt
// ESP-relative offsets. Use the virtual frame pointer, VFRAME or $T0,
// instead. In frames without stack realignment, $T0 will be the CFA.
if (RegisterId(Reg) == RegisterId::ESP) {
Reg = unsigned(RegisterId::VFRAME);
Offset += FI.OffsetAdjustment;
}
// If we can use the chosen frame pointer for the frame and this isn't a
// sliced aggregate, use the smaller S_DEFRANGE_FRAMEPOINTER_REL record.
// Otherwise, use S_DEFRANGE_REGISTER_REL.
EncodedFramePtrReg EncFP = encodeFramePtrReg(RegisterId(Reg), TheCPU);
if (!DefRange.IsSubfield && EncFP != EncodedFramePtrReg::None &&
(bool(Flags & LocalSymFlags::IsParameter)
? (EncFP == FI.EncodedParamFramePtrReg)
: (EncFP == FI.EncodedLocalFramePtrReg))) {
DefRangeFramePointerRelHeader DRHdr;
DRHdr.Offset = Offset;
OS.emitCVDefRangeDirective(Ranges, DRHdr);
} else {
uint16_t RegRelFlags = 0;
if (DefRange.IsSubfield) {
RegRelFlags = DefRangeRegisterRelSym::IsSubfieldFlag |
(DefRange.StructOffset
<< DefRangeRegisterRelSym::OffsetInParentShift);
}
DefRangeRegisterRelHeader DRHdr;
DRHdr.Register = Reg;
DRHdr.Flags = RegRelFlags;
DRHdr.BasePointerOffset = Offset;
OS.emitCVDefRangeDirective(Ranges, DRHdr);
}
} else {
assert(DefRange.DataOffset == 0 && "unexpected offset into register");
if (DefRange.IsSubfield) {
DefRangeSubfieldRegisterHeader DRHdr;
DRHdr.Register = DefRange.CVRegister;
DRHdr.MayHaveNoName = 0;
DRHdr.OffsetInParent = DefRange.StructOffset;
OS.emitCVDefRangeDirective(Ranges, DRHdr);
} else {
DefRangeRegisterHeader DRHdr;
DRHdr.Register = DefRange.CVRegister;
DRHdr.MayHaveNoName = 0;
OS.emitCVDefRangeDirective(Ranges, DRHdr);
}
}
}
}
void CodeViewDebug::emitLexicalBlockList(ArrayRef<LexicalBlock *> Blocks,
const FunctionInfo& FI) {
for (LexicalBlock *Block : Blocks)
emitLexicalBlock(*Block, FI);
}
/// Emit an S_BLOCK32 and S_END record pair delimiting the contents of a
/// lexical block scope.
void CodeViewDebug::emitLexicalBlock(const LexicalBlock &Block,
const FunctionInfo& FI) {
MCSymbol *RecordEnd = beginSymbolRecord(SymbolKind::S_BLOCK32);
OS.AddComment("PtrParent");
OS.emitInt32(0); // PtrParent
OS.AddComment("PtrEnd");
OS.emitInt32(0); // PtrEnd
OS.AddComment("Code size");
OS.emitAbsoluteSymbolDiff(Block.End, Block.Begin, 4); // Code Size
OS.AddComment("Function section relative address");
OS.emitCOFFSecRel32(Block.Begin, /*Offset=*/0); // Func Offset
OS.AddComment("Function section index");
OS.emitCOFFSectionIndex(FI.Begin); // Func Symbol
OS.AddComment("Lexical block name");
emitNullTerminatedSymbolName(OS, Block.Name); // Name
endSymbolRecord(RecordEnd);
// Emit variables local to this lexical block.
emitLocalVariableList(FI, Block.Locals);
emitGlobalVariableList(Block.Globals);
// Emit lexical blocks contained within this block.
emitLexicalBlockList(Block.Children, FI);
// Close the lexical block scope.
emitEndSymbolRecord(SymbolKind::S_END);
}
/// Convenience routine for collecting lexical block information for a list
/// of lexical scopes.
void CodeViewDebug::collectLexicalBlockInfo(
SmallVectorImpl<LexicalScope *> &Scopes,
SmallVectorImpl<LexicalBlock *> &Blocks,
SmallVectorImpl<LocalVariable> &Locals,
SmallVectorImpl<CVGlobalVariable> &Globals) {
for (LexicalScope *Scope : Scopes)
collectLexicalBlockInfo(*Scope, Blocks, Locals, Globals);
}
/// Populate the lexical blocks and local variable lists of the parent with
/// information about the specified lexical scope.
void CodeViewDebug::collectLexicalBlockInfo(
LexicalScope &Scope,
SmallVectorImpl<LexicalBlock *> &ParentBlocks,
SmallVectorImpl<LocalVariable> &ParentLocals,
SmallVectorImpl<CVGlobalVariable> &ParentGlobals) {
if (Scope.isAbstractScope())
return;
// Gather information about the lexical scope including local variables,
// global variables, and address ranges.
bool IgnoreScope = false;
auto LI = ScopeVariables.find(&Scope);
SmallVectorImpl<LocalVariable> *Locals =
LI != ScopeVariables.end() ? &LI->second : nullptr;
auto GI = ScopeGlobals.find(Scope.getScopeNode());
SmallVectorImpl<CVGlobalVariable> *Globals =
GI != ScopeGlobals.end() ? GI->second.get() : nullptr;
const DILexicalBlock *DILB = dyn_cast<DILexicalBlock>(Scope.getScopeNode());
const SmallVectorImpl<InsnRange> &Ranges = Scope.getRanges();
// Ignore lexical scopes which do not contain variables.
if (!Locals && !Globals)
IgnoreScope = true;
// Ignore lexical scopes which are not lexical blocks.
if (!DILB)
IgnoreScope = true;
// Ignore scopes which have too many address ranges to represent in the
// current CodeView format or do not have a valid address range.
//
// For lexical scopes with multiple address ranges you may be tempted to
// construct a single range covering every instruction where the block is
// live and everything in between. Unfortunately, Visual Studio only
// displays variables from the first matching lexical block scope. If the
// first lexical block contains exception handling code or cold code which
// is moved to the bottom of the routine creating a single range covering
// nearly the entire routine, then it will hide all other lexical blocks
// and the variables they contain.
if (Ranges.size() != 1 || !getLabelAfterInsn(Ranges.front().second))
IgnoreScope = true;
if (IgnoreScope) {
// This scope can be safely ignored and eliminating it will reduce the
// size of the debug information. Be sure to collect any variable and scope
// information from the this scope or any of its children and collapse them
// into the parent scope.
if (Locals)
ParentLocals.append(Locals->begin(), Locals->end());
if (Globals)
ParentGlobals.append(Globals->begin(), Globals->end());
collectLexicalBlockInfo(Scope.getChildren(),
ParentBlocks,
ParentLocals,
ParentGlobals);
return;
}
// Create a new CodeView lexical block for this lexical scope. If we've
// seen this DILexicalBlock before then the scope tree is malformed and
// we can handle this gracefully by not processing it a second time.
auto BlockInsertion = CurFn->LexicalBlocks.insert({DILB, LexicalBlock()});
if (!BlockInsertion.second)
return;
// Create a lexical block containing the variables and collect the
// lexical block information for the children.
const InsnRange &Range = Ranges.front();
assert(Range.first && Range.second);
LexicalBlock &Block = BlockInsertion.first->second;
Block.Begin = getLabelBeforeInsn(Range.first);
Block.End = getLabelAfterInsn(Range.second);
assert(Block.Begin && "missing label for scope begin");
assert(Block.End && "missing label for scope end");
Block.Name = DILB->getName();
if (Locals)
Block.Locals = std::move(*Locals);
if (Globals)
Block.Globals = std::move(*Globals);
ParentBlocks.push_back(&Block);
collectLexicalBlockInfo(Scope.getChildren(),
Block.Children,
Block.Locals,
Block.Globals);
}
void CodeViewDebug::endFunctionImpl(const MachineFunction *MF) {
const Function &GV = MF->getFunction();
assert(FnDebugInfo.count(&GV));
assert(CurFn == FnDebugInfo[&GV].get());
collectVariableInfo(GV.getSubprogram());
// Build the lexical block structure to emit for this routine.
if (LexicalScope *CFS = LScopes.getCurrentFunctionScope())
collectLexicalBlockInfo(*CFS,
CurFn->ChildBlocks,
CurFn->Locals,
CurFn->Globals);
// Clear the scope and variable information from the map which will not be
// valid after we have finished processing this routine. This also prepares
// the map for the subsequent routine.
ScopeVariables.clear();
// Don't emit anything if we don't have any line tables.
// Thunks are compiler-generated and probably won't have source correlation.
if (!CurFn->HaveLineInfo && !GV.getSubprogram()->isThunk()) {
FnDebugInfo.erase(&GV);
CurFn = nullptr;
return;
}
// Find heap alloc sites and add to list.
for (const auto &MBB : *MF) {
for (const auto &MI : MBB) {
if (MDNode *MD = MI.getHeapAllocMarker()) {
CurFn->HeapAllocSites.push_back(std::make_tuple(getLabelBeforeInsn(&MI),
getLabelAfterInsn(&MI),
dyn_cast<DIType>(MD)));
}
}
}
bool isThumb = MMI->getModule()->getTargetTriple().getArch() ==
llvm::Triple::ArchType::thumb;
collectDebugInfoForJumpTables(MF, isThumb);
CurFn->Annotations = MF->getCodeViewAnnotations();
CurFn->End = Asm->getFunctionEnd();
CurFn = nullptr;
}
// Usable locations are valid with non-zero line numbers. A line number of zero
// corresponds to optimized code that doesn't have a distinct source location.
// In this case, we try to use the previous or next source location depending on
// the context.
static bool isUsableDebugLoc(DebugLoc DL) {
return DL && DL.getLine() != 0;
}
void CodeViewDebug::beginInstruction(const MachineInstr *MI) {
DebugHandlerBase::beginInstruction(MI);
// Ignore DBG_VALUE and DBG_LABEL locations and function prologue.
if (!Asm || !CurFn || MI->isDebugInstr() ||
MI->getFlag(MachineInstr::FrameSetup))
return;
// If the first instruction of a new MBB has no location, find the first
// instruction with a location and use that.
DebugLoc DL = MI->getDebugLoc();
if (!isUsableDebugLoc(DL) && MI->getParent() != PrevInstBB) {
for (const auto &NextMI : *MI->getParent()) {
if (NextMI.isDebugInstr())
continue;
DL = NextMI.getDebugLoc();
if (isUsableDebugLoc(DL))
break;
}
// FIXME: Handle the case where the BB has no valid locations. This would
// probably require doing a real dataflow analysis.
}
PrevInstBB = MI->getParent();
// If we still don't have a debug location, don't record a location.
if (!isUsableDebugLoc(DL))
return;
maybeRecordLocation(DL, Asm->MF);
}
MCSymbol *CodeViewDebug::beginCVSubsection(DebugSubsectionKind Kind) {
MCSymbol *BeginLabel = MMI->getContext().createTempSymbol(),
*EndLabel = MMI->getContext().createTempSymbol();
OS.emitInt32(unsigned(Kind));
OS.AddComment("Subsection size");
OS.emitAbsoluteSymbolDiff(EndLabel, BeginLabel, 4);
OS.emitLabel(BeginLabel);
return EndLabel;
}
void CodeViewDebug::endCVSubsection(MCSymbol *EndLabel) {
OS.emitLabel(EndLabel);
// Every subsection must be aligned to a 4-byte boundary.
OS.emitValueToAlignment(Align(4));
}
static StringRef getSymbolName(SymbolKind SymKind) {
for (const EnumEntry<SymbolKind> &EE : getSymbolTypeNames())
if (EE.Value == SymKind)
return EE.Name;
return "";
}
MCSymbol *CodeViewDebug::beginSymbolRecord(SymbolKind SymKind) {
MCSymbol *BeginLabel = MMI->getContext().createTempSymbol(),
*EndLabel = MMI->getContext().createTempSymbol();
OS.AddComment("Record length");
OS.emitAbsoluteSymbolDiff(EndLabel, BeginLabel, 2);
OS.emitLabel(BeginLabel);
if (OS.isVerboseAsm())
OS.AddComment("Record kind: " + getSymbolName(SymKind));
OS.emitInt16(unsigned(SymKind));
return EndLabel;
}
void CodeViewDebug::endSymbolRecord(MCSymbol *SymEnd) {
// MSVC does not pad out symbol records to four bytes, but LLVM does to avoid
// an extra copy of every symbol record in LLD. This increases object file
// size by less than 1% in the clang build, and is compatible with the Visual
// C++ linker.
OS.emitValueToAlignment(Align(4));
OS.emitLabel(SymEnd);
}
void CodeViewDebug::emitEndSymbolRecord(SymbolKind EndKind) {
OS.AddComment("Record length");
OS.emitInt16(2);
if (OS.isVerboseAsm())
OS.AddComment("Record kind: " + getSymbolName(EndKind));
OS.emitInt16(uint16_t(EndKind)); // Record Kind
}
void CodeViewDebug::emitDebugInfoForUDTs(
const std::vector<std::pair<std::string, const DIType *>> &UDTs) {
#ifndef NDEBUG
size_t OriginalSize = UDTs.size();
#endif
for (const auto &UDT : UDTs) {
const DIType *T = UDT.second;
assert(shouldEmitUdt(T));
MCSymbol *UDTRecordEnd = beginSymbolRecord(SymbolKind::S_UDT);
OS.AddComment("Type");
OS.emitInt32(getCompleteTypeIndex(T).getIndex());
assert(OriginalSize == UDTs.size() &&
"getCompleteTypeIndex found new UDTs!");
emitNullTerminatedSymbolName(OS, UDT.first);
endSymbolRecord(UDTRecordEnd);
}
}
void CodeViewDebug::collectGlobalVariableInfo() {
DenseMap<const DIGlobalVariableExpression *, const GlobalVariable *>
GlobalMap;
for (const GlobalVariable &GV : MMI->getModule()->globals()) {
SmallVector<DIGlobalVariableExpression *, 1> GVEs;
GV.getDebugInfo(GVEs);
for (const auto *GVE : GVEs)
GlobalMap[GVE] = &GV;
}
NamedMDNode *CUs = MMI->getModule()->getNamedMetadata("llvm.dbg.cu");
for (const MDNode *Node : CUs->operands()) {
const auto *CU = cast<DICompileUnit>(Node);
for (const auto *GVE : CU->getGlobalVariables()) {
const DIGlobalVariable *DIGV = GVE->getVariable();
const DIExpression *DIE = GVE->getExpression();
// Don't emit string literals in CodeView, as the only useful parts are
// generally the filename and line number, which isn't possible to output
// in CodeView. String literals should be the only unnamed GlobalVariable
// with debug info.
if (DIGV->getName().empty()) continue;
if ((DIE->getNumElements() == 2) &&
(DIE->getElement(0) == dwarf::DW_OP_plus_uconst))
// Record the constant offset for the variable.
//
// A Fortran common block uses this idiom to encode the offset
// of a variable from the common block's starting address.
CVGlobalVariableOffsets.insert(
std::make_pair(DIGV, DIE->getElement(1)));
// Emit constant global variables in a global symbol section.
if (GlobalMap.count(GVE) == 0 && DIE->isConstant()) {
CVGlobalVariable CVGV = {DIGV, DIE};
GlobalVariables.emplace_back(std::move(CVGV));
}
const auto *GV = GlobalMap.lookup(GVE);
if (!GV || GV->isDeclarationForLinker())
continue;
DIScope *Scope = DIGV->getScope();
SmallVector<CVGlobalVariable, 1> *VariableList;
if (Scope && isa<DILocalScope>(Scope)) {
// Locate a global variable list for this scope, creating one if
// necessary.
auto Insertion = ScopeGlobals.insert(
{Scope, std::unique_ptr<GlobalVariableList>()});
if (Insertion.second)
Insertion.first->second = std::make_unique<GlobalVariableList>();
VariableList = Insertion.first->second.get();
} else if (GV->hasComdat())
// Emit this global variable into a COMDAT section.
VariableList = &ComdatVariables;
else
// Emit this global variable in a single global symbol section.
VariableList = &GlobalVariables;
CVGlobalVariable CVGV = {DIGV, GV};
VariableList->emplace_back(std::move(CVGV));
}
}
}
void CodeViewDebug::collectDebugInfoForGlobals() {
for (const CVGlobalVariable &CVGV : GlobalVariables) {
const DIGlobalVariable *DIGV = CVGV.DIGV;
const DIScope *Scope = DIGV->getScope();
getCompleteTypeIndex(DIGV->getType());
getFullyQualifiedName(Scope, DIGV->getName());
}
for (const CVGlobalVariable &CVGV : ComdatVariables) {
const DIGlobalVariable *DIGV = CVGV.DIGV;
const DIScope *Scope = DIGV->getScope();
getCompleteTypeIndex(DIGV->getType());
getFullyQualifiedName(Scope, DIGV->getName());
}
}
void CodeViewDebug::emitDebugInfoForGlobals() {
// First, emit all globals that are not in a comdat in a single symbol
// substream. MSVC doesn't like it if the substream is empty, so only open
// it if we have at least one global to emit.
switchToDebugSectionForSymbol(nullptr);
if (!GlobalVariables.empty() || !StaticConstMembers.empty()) {
OS.AddComment("Symbol subsection for globals");
MCSymbol *EndLabel = beginCVSubsection(DebugSubsectionKind::Symbols);
emitGlobalVariableList(GlobalVariables);
emitStaticConstMemberList();
endCVSubsection(EndLabel);
}
// Second, emit each global that is in a comdat into its own .debug$S
// section along with its own symbol substream.
for (const CVGlobalVariable &CVGV : ComdatVariables) {
const GlobalVariable *GV = cast<const GlobalVariable *>(CVGV.GVInfo);
MCSymbol *GVSym = Asm->getSymbol(GV);
OS.AddComment("Symbol subsection for " +
Twine(GlobalValue::dropLLVMManglingEscape(GV->getName())));
switchToDebugSectionForSymbol(GVSym);
MCSymbol *EndLabel = beginCVSubsection(DebugSubsectionKind::Symbols);
// FIXME: emitDebugInfoForGlobal() doesn't handle DIExpressions.
emitDebugInfoForGlobal(CVGV);
endCVSubsection(EndLabel);
}
}
void CodeViewDebug::emitDebugInfoForRetainedTypes() {
NamedMDNode *CUs = MMI->getModule()->getNamedMetadata("llvm.dbg.cu");
for (const MDNode *Node : CUs->operands()) {
for (auto *Ty : cast<DICompileUnit>(Node)->getRetainedTypes()) {
if (DIType *RT = dyn_cast<DIType>(Ty)) {
getTypeIndex(RT);
// FIXME: Add to global/local DTU list.
}
}
}
}
// Emit each global variable in the specified array.
void CodeViewDebug::emitGlobalVariableList(ArrayRef<CVGlobalVariable> Globals) {
for (const CVGlobalVariable &CVGV : Globals) {
// FIXME: emitDebugInfoForGlobal() doesn't handle DIExpressions.
emitDebugInfoForGlobal(CVGV);
}
}
void CodeViewDebug::emitConstantSymbolRecord(const DIType *DTy, APSInt &Value,
const std::string &QualifiedName) {
MCSymbol *SConstantEnd = beginSymbolRecord(SymbolKind::S_CONSTANT);
OS.AddComment("Type");
OS.emitInt32(getTypeIndex(DTy).getIndex());
OS.AddComment("Value");
// Encoded integers shouldn't need more than 10 bytes.
uint8_t Data[10];
BinaryStreamWriter Writer(Data, llvm::endianness::little);
CodeViewRecordIO IO(Writer);
cantFail(IO.mapEncodedInteger(Value));
StringRef SRef((char *)Data, Writer.getOffset());
OS.emitBinaryData(SRef);
OS.AddComment("Name");
emitNullTerminatedSymbolName(OS, QualifiedName);
endSymbolRecord(SConstantEnd);
}
void CodeViewDebug::emitStaticConstMemberList() {
for (const DIDerivedType *DTy : StaticConstMembers) {
const DIScope *Scope = DTy->getScope();
APSInt Value;
if (const ConstantInt *CI =
dyn_cast_or_null<ConstantInt>(DTy->getConstant()))
Value = APSInt(CI->getValue(),
DebugHandlerBase::isUnsignedDIType(DTy->getBaseType()));
else if (const ConstantFP *CFP =
dyn_cast_or_null<ConstantFP>(DTy->getConstant()))
Value = APSInt(CFP->getValueAPF().bitcastToAPInt(), true);
else
llvm_unreachable("cannot emit a constant without a value");
emitConstantSymbolRecord(DTy->getBaseType(), Value,
getFullyQualifiedName(Scope, DTy->getName()));
}
}
static bool isFloatDIType(const DIType *Ty) {
if (isa<DICompositeType>(Ty))
return false;
if (auto *DTy = dyn_cast<DIDerivedType>(Ty)) {
dwarf::Tag T = (dwarf::Tag)Ty->getTag();
if (T == dwarf::DW_TAG_pointer_type ||
T == dwarf::DW_TAG_ptr_to_member_type ||
T == dwarf::DW_TAG_reference_type ||
T == dwarf::DW_TAG_rvalue_reference_type)
return false;
assert(DTy->getBaseType() && "Expected valid base type");
return isFloatDIType(DTy->getBaseType());
}
auto *BTy = cast<DIBasicType>(Ty);
return (BTy->getEncoding() == dwarf::DW_ATE_float);
}
void CodeViewDebug::emitDebugInfoForGlobal(const CVGlobalVariable &CVGV) {
const DIGlobalVariable *DIGV = CVGV.DIGV;
const DIScope *Scope = DIGV->getScope();
// For static data members, get the scope from the declaration.
if (const auto *MemberDecl = dyn_cast_or_null<DIDerivedType>(
DIGV->getRawStaticDataMemberDeclaration()))
Scope = MemberDecl->getScope();
// For static local variables and Fortran, the scoping portion is elided
// in its name so that we can reference the variable in the command line
// of the VS debugger.
std::string QualifiedName =
(moduleIsInFortran() || (Scope && isa<DILocalScope>(Scope)))
? std::string(DIGV->getName())
: getFullyQualifiedName(Scope, DIGV->getName());
if (const GlobalVariable *GV =
dyn_cast_if_present<const GlobalVariable *>(CVGV.GVInfo)) {
// DataSym record, see SymbolRecord.h for more info. Thread local data
// happens to have the same format as global data.
MCSymbol *GVSym = Asm->getSymbol(GV);
SymbolKind DataSym = GV->isThreadLocal()
? (DIGV->isLocalToUnit() ? SymbolKind::S_LTHREAD32
: SymbolKind::S_GTHREAD32)
: (DIGV->isLocalToUnit() ? SymbolKind::S_LDATA32
: SymbolKind::S_GDATA32);
MCSymbol *DataEnd = beginSymbolRecord(DataSym);
OS.AddComment("Type");
OS.emitInt32(getCompleteTypeIndex(DIGV->getType()).getIndex());
OS.AddComment("DataOffset");
// Use the offset seen while collecting info on globals.
uint64_t Offset = CVGlobalVariableOffsets.lookup(DIGV);
OS.emitCOFFSecRel32(GVSym, Offset);
OS.AddComment("Segment");
OS.emitCOFFSectionIndex(GVSym);
OS.AddComment("Name");
const unsigned LengthOfDataRecord = 12;
emitNullTerminatedSymbolName(OS, QualifiedName, LengthOfDataRecord);
endSymbolRecord(DataEnd);
} else {
const DIExpression *DIE = cast<const DIExpression *>(CVGV.GVInfo);
assert(DIE->isConstant() &&
"Global constant variables must contain a constant expression.");
// Use unsigned for floats.
bool isUnsigned = isFloatDIType(DIGV->getType())
? true
: DebugHandlerBase::isUnsignedDIType(DIGV->getType());
APSInt Value(APInt(/*BitWidth=*/64, DIE->getElement(1)), isUnsigned);
emitConstantSymbolRecord(DIGV->getType(), Value, QualifiedName);
}
}
void forEachJumpTableBranch(
const MachineFunction *MF, bool isThumb,
const std::function<void(const MachineJumpTableInfo &, const MachineInstr &,
int64_t)> &Callback) {
auto JTI = MF->getJumpTableInfo();
if (JTI && !JTI->isEmpty()) {
#ifndef NDEBUG
auto UsedJTs = llvm::SmallBitVector(JTI->getJumpTables().size());
#endif
for (const auto &MBB : *MF) {
// Search for indirect branches...
const auto LastMI = MBB.getFirstTerminator();
if (LastMI != MBB.end() && LastMI->isIndirectBranch()) {
if (isThumb) {
// ... that directly use jump table operands.
// NOTE: ARM uses pattern matching to lower its BR_JT SDNode to
// machine instructions, hence inserting a JUMP_TABLE_DEBUG_INFO node
// interferes with this process *but* the resulting pseudo-instruction
// uses a Jump Table operand, so extract the jump table index directly
// from that.
for (const auto &MO : LastMI->operands()) {
if (MO.isJTI()) {
unsigned Index = MO.getIndex();
#ifndef NDEBUG
UsedJTs.set(Index);
#endif
Callback(*JTI, *LastMI, Index);
break;
}
}
} else {
// ... that have jump table debug info.
// NOTE: The debug info is inserted as a JUMP_TABLE_DEBUG_INFO node
// when lowering the BR_JT SDNode to an indirect branch.
for (auto I = MBB.instr_rbegin(), E = MBB.instr_rend(); I != E; ++I) {
if (I->isJumpTableDebugInfo()) {
unsigned Index = I->getOperand(0).getImm();
#ifndef NDEBUG
UsedJTs.set(Index);
#endif
Callback(*JTI, *LastMI, Index);
break;
}
}
}
}
}
#ifndef NDEBUG
assert(UsedJTs.all() &&
"Some of jump tables were not used in a debug info instruction");
#endif
}
}
void CodeViewDebug::discoverJumpTableBranches(const MachineFunction *MF,
bool isThumb) {
forEachJumpTableBranch(
MF, isThumb,
[this](const MachineJumpTableInfo &, const MachineInstr &BranchMI,
int64_t) { requestLabelBeforeInsn(&BranchMI); });
}
void CodeViewDebug::collectDebugInfoForJumpTables(const MachineFunction *MF,
bool isThumb) {
forEachJumpTableBranch(
MF, isThumb,
[this, MF](const MachineJumpTableInfo &JTI, const MachineInstr &BranchMI,
int64_t JumpTableIndex) {
// For label-difference jump tables, find the base expression.
// Otherwise the jump table uses an absolute address (so no base
// is required).
const MCSymbol *Base;
uint64_t BaseOffset = 0;
const MCSymbol *Branch = getLabelBeforeInsn(&BranchMI);
JumpTableEntrySize EntrySize;
switch (JTI.getEntryKind()) {
case MachineJumpTableInfo::EK_Custom32:
case MachineJumpTableInfo::EK_GPRel32BlockAddress:
case MachineJumpTableInfo::EK_GPRel64BlockAddress:
llvm_unreachable(
"EK_Custom32, EK_GPRel32BlockAddress, and "
"EK_GPRel64BlockAddress should never be emitted for COFF");
case MachineJumpTableInfo::EK_BlockAddress:
// Each entry is an absolute address.
EntrySize = JumpTableEntrySize::Pointer;
Base = nullptr;
break;
case MachineJumpTableInfo::EK_Inline:
case MachineJumpTableInfo::EK_LabelDifference32:
case MachineJumpTableInfo::EK_LabelDifference64:
// Ask the AsmPrinter.
std::tie(Base, BaseOffset, Branch, EntrySize) =
Asm->getCodeViewJumpTableInfo(JumpTableIndex, &BranchMI, Branch);
break;
}
CurFn->JumpTables.push_back(
{EntrySize, Base, BaseOffset, Branch,
MF->getJTISymbol(JumpTableIndex, MMI->getContext()),
JTI.getJumpTables()[JumpTableIndex].MBBs.size()});
});
}
void CodeViewDebug::emitDebugInfoForJumpTables(const FunctionInfo &FI) {
for (auto JumpTable : FI.JumpTables) {
MCSymbol *JumpTableEnd = beginSymbolRecord(SymbolKind::S_ARMSWITCHTABLE);
if (JumpTable.Base) {
OS.AddComment("Base offset");
OS.emitCOFFSecRel32(JumpTable.Base, JumpTable.BaseOffset);
OS.AddComment("Base section index");
OS.emitCOFFSectionIndex(JumpTable.Base);
} else {
OS.AddComment("Base offset");
OS.emitInt32(0);
OS.AddComment("Base section index");
OS.emitInt16(0);
}
OS.AddComment("Switch type");
OS.emitInt16(static_cast<uint16_t>(JumpTable.EntrySize));
OS.AddComment("Branch offset");
OS.emitCOFFSecRel32(JumpTable.Branch, /*Offset=*/0);
OS.AddComment("Table offset");
OS.emitCOFFSecRel32(JumpTable.Table, /*Offset=*/0);
OS.AddComment("Branch section index");
OS.emitCOFFSectionIndex(JumpTable.Branch);
OS.AddComment("Table section index");
OS.emitCOFFSectionIndex(JumpTable.Table);
OS.AddComment("Entries count");
OS.emitInt32(JumpTable.TableSize);
endSymbolRecord(JumpTableEnd);
}
}
void CodeViewDebug::emitInlinees(
const SmallSet<codeview::TypeIndex, 1> &Inlinees) {
// Divide the list of inlinees into chunks such that each chunk fits within
// one record.
constexpr size_t ChunkSize =
(MaxRecordLength - sizeof(SymbolKind) - sizeof(uint32_t)) /
sizeof(uint32_t);
SmallVector<TypeIndex> SortedInlinees{Inlinees.begin(), Inlinees.end()};
llvm::sort(SortedInlinees);
size_t CurrentIndex = 0;
while (CurrentIndex < SortedInlinees.size()) {
auto Symbol = beginSymbolRecord(SymbolKind::S_INLINEES);
auto CurrentChunkSize =
std::min(ChunkSize, SortedInlinees.size() - CurrentIndex);
OS.AddComment("Count");
OS.emitInt32(CurrentChunkSize);
const size_t CurrentChunkEnd = CurrentIndex + CurrentChunkSize;
for (; CurrentIndex < CurrentChunkEnd; ++CurrentIndex) {
OS.AddComment("Inlinee");
OS.emitInt32(SortedInlinees[CurrentIndex].getIndex());
}
endSymbolRecord(Symbol);
}
}
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