shylie/llvm-project
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
llvm-project/llvm/tools/llvm-dwarfutil/DebugInfoLinker.cpp
Alexey Lapshin 4c273cd071 [DWARFLinker] Refactor cloneAddressAttribute(). 
As a preparation for implementing DWARFv5 address ranges generation,
this patch refactors cloneAddressAttribute() method. It has special
handling for addresses which can be relocated in some unrelated value,
for applying relocations twice, for indexed addresses. Instead of
all these special handlings this patch uses general handling:

Read attribute value from InputDIE and apply PCOffset.

Another thing is that current handling of DW_FORM_addrx misses the
fact that relocations might be applied twice in some cases. This
patch fixes this problem also.

Differential Revision: https://reviews.llvm.org/D143269
2023-02-13 12:25:22 +01:00

425 lines
15 KiB
C++
Raw Blame History

//=== DebugInfoLinker.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
//
//===----------------------------------------------------------------------===//
#include "DebugInfoLinker.h"
#include "Error.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/DWARFLinker/DWARFLinker.h"
#include "llvm/DWARFLinker/DWARFStreamer.h"
#include "llvm/DebugInfo/DWARF/DWARFContext.h"
#include "llvm/DebugInfo/DWARF/DWARFExpression.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Support/Endian.h"
#include <memory>
#include <vector>
namespace llvm {
namespace dwarfutil {
// ObjFileAddressMap allows to check whether specified DIE referencing
// dead addresses. It uses tombstone values to determine dead addresses.
// The concrete values of tombstone constants were discussed in
// https://reviews.llvm.org/D81784 and https://reviews.llvm.org/D84825.
// So we use following values as indicators of dead addresses:
//
// bfd: (LowPC == 0) or (LowPC == 1 and HighPC == 1 and DWARF v4 (or less))
// or ([LowPC, HighPC] is not inside address ranges of .text sections).
//
// maxpc: (LowPC == -1) or (LowPC == -2 and DWARF v4 (or less))
// That value is assumed to be compatible with
// http://www.dwarfstd.org/ShowIssue.php?issue=200609.1
//
// exec: [LowPC, HighPC] is not inside address ranges of .text sections
//
// universal: maxpc and bfd
class ObjFileAddressMap : public AddressesMap {
public:
ObjFileAddressMap(DWARFContext &Context, const Options &Options,
object::ObjectFile &ObjFile)
: Opts(Options) {
// Remember addresses of existing text sections.
for (const object::SectionRef &Sect : ObjFile.sections()) {
if (!Sect.isText())
continue;
const uint64_t Size = Sect.getSize();
if (Size == 0)
continue;
const uint64_t StartAddr = Sect.getAddress();
TextAddressRanges.insert({StartAddr, StartAddr + Size});
}
// Check CU address ranges for tombstone value.
for (std::unique_ptr<DWARFUnit> &CU : Context.compile_units()) {
Expected<llvm::DWARFAddressRangesVector> ARanges =
CU->getUnitDIE().getAddressRanges();
if (ARanges) {
for (auto &Range : *ARanges) {
if (!isDeadAddressRange(Range.LowPC, Range.HighPC, CU->getVersion(),
Options.Tombstone, CU->getAddressByteSize()))
DWARFAddressRanges.insert({Range.LowPC, Range.HighPC}, 0);
}
}
}
}
// should be renamed into has valid address ranges
bool hasValidRelocs() override { return !DWARFAddressRanges.empty(); }
bool isLiveSubprogram(const DWARFDie &DIE,
CompileUnit::DIEInfo &Info) override {
assert((DIE.getTag() == dwarf::DW_TAG_subprogram ||
DIE.getTag() == dwarf::DW_TAG_label) &&
"Wrong type of input die");
if (std::optional<uint64_t> LowPC =
dwarf::toAddress(DIE.find(dwarf::DW_AT_low_pc))) {
if (!isDeadAddress(*LowPC, DIE.getDwarfUnit()->getVersion(),
Opts.Tombstone,
DIE.getDwarfUnit()->getAddressByteSize())) {
Info.AddrAdjust = 0;
Info.InDebugMap = true;
return true;
}
}
return false;
}
bool isLiveVariable(const DWARFDie &DIE,
CompileUnit::DIEInfo &Info) override {
assert((DIE.getTag() == dwarf::DW_TAG_variable ||
DIE.getTag() == dwarf::DW_TAG_constant) &&
"Wrong type of input die");
if (Expected<DWARFLocationExpressionsVector> Loc =
DIE.getLocations(dwarf::DW_AT_location)) {
DWARFUnit *U = DIE.getDwarfUnit();
for (const auto &Entry : *Loc) {
DataExtractor Data(toStringRef(Entry.Expr),
U->getContext().isLittleEndian(), 0);
DWARFExpression Expression(Data, U->getAddressByteSize(),
U->getFormParams().Format);
bool HasLiveAddresses =
any_of(Expression, [&](const DWARFExpression::Operation &Op) {
// TODO: add handling of dwarf::DW_OP_addrx
return !Op.isError() &&
(Op.getCode() == dwarf::DW_OP_addr &&
!isDeadAddress(Op.getRawOperand(0), U->getVersion(),
Opts.Tombstone,
DIE.getDwarfUnit()->getAddressByteSize()));
});
if (HasLiveAddresses) {
Info.AddrAdjust = 0;
Info.InDebugMap = true;
return true;
}
}
} else {
// FIXME: missing DW_AT_location is OK here, but other errors should be
// reported to the user.
consumeError(Loc.takeError());
}
return false;
}
bool applyValidRelocs(MutableArrayRef<char>, uint64_t, bool) override {
// no need to apply relocations to the linked binary.
return false;
}
RangesTy &getValidAddressRanges() override { return DWARFAddressRanges; };
void clear() override { DWARFAddressRanges.clear(); }
protected:
// returns true if specified address range is inside address ranges
// of executable sections.
bool isInsideExecutableSectionsAddressRange(uint64_t LowPC,
std::optional<uint64_t> HighPC) {
std::optional<AddressRange> Range =
TextAddressRanges.getRangeThatContains(LowPC);
if (HighPC)
return Range.has_value() && Range->end() >= *HighPC;
return Range.has_value();
}
uint64_t isBFDDeadAddressRange(uint64_t LowPC, std::optional<uint64_t> HighPC,
uint16_t Version) {
if (LowPC == 0)
return true;
if ((Version <= 4) && HighPC && (LowPC == 1 && *HighPC == 1))
return true;
return !isInsideExecutableSectionsAddressRange(LowPC, HighPC);
}
uint64_t isMAXPCDeadAddressRange(uint64_t LowPC,
std::optional<uint64_t> HighPC,
uint16_t Version, uint8_t AddressByteSize) {
if (Version <= 4 && HighPC) {
if (LowPC == (dwarf::computeTombstoneAddress(AddressByteSize) - 1))
return true;
} else if (LowPC == dwarf::computeTombstoneAddress(AddressByteSize))
return true;
if (!isInsideExecutableSectionsAddressRange(LowPC, HighPC))
warning("Address referencing invalid text section is not marked with "
"tombstone value");
return false;
}
bool isDeadAddressRange(uint64_t LowPC, std::optional<uint64_t> HighPC,
uint16_t Version, TombstoneKind Tombstone,
uint8_t AddressByteSize) {
switch (Tombstone) {
case TombstoneKind::BFD:
return isBFDDeadAddressRange(LowPC, HighPC, Version);
case TombstoneKind::MaxPC:
return isMAXPCDeadAddressRange(LowPC, HighPC, Version, AddressByteSize);
case TombstoneKind::Universal:
return isBFDDeadAddressRange(LowPC, HighPC, Version) ||
isMAXPCDeadAddressRange(LowPC, HighPC, Version, AddressByteSize);
case TombstoneKind::Exec:
return !isInsideExecutableSectionsAddressRange(LowPC, HighPC);
}
llvm_unreachable("Unknown tombstone value");
}
bool isDeadAddress(uint64_t LowPC, uint16_t Version, TombstoneKind Tombstone,
uint8_t AddressByteSize) {
return isDeadAddressRange(LowPC, std::nullopt, Version, Tombstone,
AddressByteSize);
}
private:
RangesTy DWARFAddressRanges;
AddressRanges TextAddressRanges;
const Options &Opts;
};
static bool knownByDWARFUtil(StringRef SecName) {
return llvm::StringSwitch<bool>(SecName)
.Case(".debug_info", true)
.Case(".debug_types", true)
.Case(".debug_abbrev", true)
.Case(".debug_loc", true)
.Case(".debug_loclists", true)
.Case(".debug_frame", true)
.Case(".debug_aranges", true)
.Case(".debug_ranges", true)
.Case(".debug_rnglists", true)
.Case(".debug_line", true)
.Case(".debug_line_str", true)
.Case(".debug_addr", true)
.Case(".debug_macro", true)
.Case(".debug_macinfo", true)
.Case(".debug_str", true)
.Case(".debug_str_offsets", true)
.Case(".debug_pubnames", true)
.Case(".debug_pubtypes", true)
.Case(".debug_names", true)
.Default(false);
}
static std::optional<DwarfLinkerAccelTableKind>
getAcceleratorTableKind(StringRef SecName) {
return llvm::StringSwitch<std::optional<DwarfLinkerAccelTableKind>>(SecName)
.Case(".debug_pubnames", DwarfLinkerAccelTableKind::Pub)
.Case(".debug_pubtypes", DwarfLinkerAccelTableKind::Pub)
.Case(".debug_names", DwarfLinkerAccelTableKind::DebugNames)
.Default(std::nullopt);
}
static std::string getMessageForReplacedAcceleratorTables(
SmallVector<StringRef> &AccelTableNamesToReplace,
DwarfUtilAccelKind TargetTable) {
std::string Message;
Message += "'";
for (StringRef Name : AccelTableNamesToReplace) {
if (Message.size() > 1)
Message += ", ";
Message += Name;
}
Message += "' will be replaced with requested ";
switch (TargetTable) {
case DwarfUtilAccelKind::DWARF:
Message += ".debug_names table";
break;
default:
assert(false);
}
return Message;
}
static std::string getMessageForDeletedAcceleratorTables(
SmallVector<StringRef> &AccelTableNamesToReplace) {
std::string Message;
Message += "'";
for (StringRef Name : AccelTableNamesToReplace) {
if (Message.size() > 1)
Message += ", ";
Message += Name;
}
Message += "' will be deleted as no accelerator tables are requested";
return Message;
}
Error linkDebugInfo(object::ObjectFile &File, const Options &Options,
raw_pwrite_stream &OutStream) {
auto ReportWarn = [&](const Twine &Message, StringRef Context,
const DWARFDie *Die) {
warning(Message, Context);
if (!Options.Verbose || !Die)
return;
DIDumpOptions DumpOpts;
DumpOpts.ChildRecurseDepth = 0;
DumpOpts.Verbose = Options.Verbose;
WithColor::note() << " in DIE:\n";
Die->dump(errs(), /*Indent=*/6, DumpOpts);
};
auto ReportErr = [&](const Twine &Message, StringRef Context,
const DWARFDie *) {
WithColor::error(errs(), Context) << Message << '\n';
};
// Create output streamer.
DwarfStreamer OutStreamer(OutputFileType::Object, OutStream, nullptr,
ReportWarn, ReportWarn);
Triple TargetTriple = File.makeTriple();
if (!OutStreamer.init(TargetTriple, formatv("cannot create a stream for {0}",
TargetTriple.getTriple())
.str()))
return createStringError(std::errc::invalid_argument, "");
std::unique_ptr<DWARFContext> Context = DWARFContext::create(File);
// Create DWARF linker.
DWARFLinker DebugInfoLinker(&OutStreamer, DwarfLinkerClient::LLD);
DebugInfoLinker.setEstimatedObjfilesAmount(1);
DebugInfoLinker.setErrorHandler(ReportErr);
DebugInfoLinker.setWarningHandler(ReportWarn);
DebugInfoLinker.setNumThreads(Options.NumThreads);
DebugInfoLinker.setNoODR(!Options.DoODRDeduplication);
DebugInfoLinker.setVerbosity(Options.Verbose);
DebugInfoLinker.setUpdate(!Options.DoGarbageCollection);
std::vector<std::unique_ptr<DWARFFile>> ObjectsForLinking(1);
std::vector<std::unique_ptr<AddressesMap>> AddresssMapForLinking(1);
std::vector<std::string> EmptyWarnings;
// Add object files to the DWARFLinker.
AddresssMapForLinking[0] =
std::make_unique<ObjFileAddressMap>(*Context, Options, File);
ObjectsForLinking[0] = std::make_unique<DWARFFile>(
File.getFileName(), &*Context, AddresssMapForLinking[0].get(),
EmptyWarnings);
uint16_t MaxDWARFVersion = 0;
std::function<void(const DWARFUnit &Unit)> OnCUDieLoaded =
[&MaxDWARFVersion](const DWARFUnit &Unit) {
MaxDWARFVersion = std::max(Unit.getVersion(), MaxDWARFVersion);
};
for (size_t I = 0; I < ObjectsForLinking.size(); I++)
DebugInfoLinker.addObjectFile(*ObjectsForLinking[I], nullptr,
OnCUDieLoaded);
// If we haven't seen any CUs, pick an arbitrary valid Dwarf version anyway.
if (MaxDWARFVersion == 0)
MaxDWARFVersion = 3;
if (Error Err = DebugInfoLinker.setTargetDWARFVersion(MaxDWARFVersion))
return Err;
SmallVector<DwarfLinkerAccelTableKind> AccelTables;
switch (Options.AccelTableKind) {
case DwarfUtilAccelKind::None:
// Nothing to do.
break;
case DwarfUtilAccelKind::DWARF:
// use .debug_names for all DWARF versions.
AccelTables.push_back(DwarfLinkerAccelTableKind::DebugNames);
break;
}
// Add accelerator tables to DWARFLinker.
for (DwarfLinkerAccelTableKind Table : AccelTables)
DebugInfoLinker.addAccelTableKind(Table);
SmallVector<StringRef> AccelTableNamesToReplace;
SmallVector<StringRef> AccelTableNamesToDelete;
// Unknown debug sections or non-requested accelerator sections would be
// removed. Display warning for such sections.
for (SectionName Sec : Context->getDWARFObj().getSectionNames()) {
if (isDebugSection(Sec.Name)) {
std::optional<DwarfLinkerAccelTableKind> SrcAccelTableKind =
getAcceleratorTableKind(Sec.Name);
if (SrcAccelTableKind) {
assert(knownByDWARFUtil(Sec.Name));
if (Options.AccelTableKind == DwarfUtilAccelKind::None)
AccelTableNamesToDelete.push_back(Sec.Name);
else if (std::find(AccelTables.begin(), AccelTables.end(),
*SrcAccelTableKind) == AccelTables.end())
AccelTableNamesToReplace.push_back(Sec.Name);
} else if (!knownByDWARFUtil(Sec.Name)) {
assert(!SrcAccelTableKind);
warning(
formatv("'{0}' is not currently supported: section will be skipped",
Sec.Name),
Options.InputFileName);
}
}
}
// Display message for the replaced accelerator tables.
if (!AccelTableNamesToReplace.empty())
warning(getMessageForReplacedAcceleratorTables(AccelTableNamesToReplace,
Options.AccelTableKind),
Options.InputFileName);
// Display message for the removed accelerator tables.
if (!AccelTableNamesToDelete.empty())
warning(getMessageForDeletedAcceleratorTables(AccelTableNamesToDelete),
Options.InputFileName);
// Link debug info.
if (Error Err = DebugInfoLinker.link())
return Err;
OutStreamer.finish();
return Error::success();
}
} // end of namespace dwarfutil
} // end of namespace llvm
Reference in New Issue View Git Blame Copy Permalink