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Convert BuildIdSection to input section 

Differential revision: https://reviews.llvm.org/D25627

llvm-svn: 285682
This commit is contained in:
Eugene Leviant 2016-11-01 09:49:24 +00:00
parent e70fa63390
commit 282251a226
6 changed files with 179 additions and 166 deletions
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89
lld/ELF/InputSection.cpp
View File

@ -19,6 +19,8 @@
#include "llvm/Support/Compression.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/RandomNumberGenerator.h"
#include "llvm/Support/xxhash.h"
using namespace llvm;
using namespace llvm::ELF;
@ -480,6 +482,9 @@ template <class ELFT> void InputSection<ELFT>::writeTo(uint8_t *Buf) {
if (this->Type == SHT_NOBITS)
return;
// Set output location.
this->OutputLoc = Buf + OutSecOff;
// If -r is given, then an InputSection may be a relocation section.
if (this->Type == SHT_RELA) {
copyRelocations(Buf + OutSecOff, this->template getDataAs<Elf_Rela>());
@ -848,6 +853,60 @@ InputSection<ELFT> InputSection<ELFT>::createCommonInputSection(
return Ret;
}
template <class ELFT>
BuildIdSection<ELFT>::BuildIdSection(size_t HashSize)
: InputSection<ELFT>(SHF_ALLOC, SHT_NOTE, 1, ArrayRef<uint8_t>(),
".note.gnu.build-id") {
Buf.resize(16 + HashSize);
const endianness E = ELFT::TargetEndianness;
write32<E>(Buf.data(), 4); // Name size
write32<E>(Buf.data() + 4, HashSize); // Content size
write32<E>(Buf.data() + 8, NT_GNU_BUILD_ID); // Type
memcpy(Buf.data() + 12, "GNU", 4); // Name string
this->Data = ArrayRef<uint8_t>(Buf);
}
template <class ELFT>
void BuildIdFastHash<ELFT>::writeBuildId(ArrayRef<uint8_t> Buf) {
const endianness E = ELFT::TargetEndianness;
// 64-bit xxhash
uint64_t Hash = xxHash64(toStringRef(Buf));
write64<E>(this->OutputLoc + 16, Hash);
}
template <class ELFT>
void BuildIdMd5<ELFT>::writeBuildId(ArrayRef<uint8_t> Buf) {
MD5 Hash;
Hash.update(Buf);
MD5::MD5Result Res;
Hash.final(Res);
memcpy(this->OutputLoc + 16, Res, 16);
}
template <class ELFT>
void BuildIdSha1<ELFT>::writeBuildId(ArrayRef<uint8_t> Buf) {
SHA1 Hash;
Hash.update(Buf);
memcpy(this->OutputLoc + 16, Hash.final().data(), 20);
}
template <class ELFT>
void BuildIdUuid<ELFT>::writeBuildId(ArrayRef<uint8_t> Buf) {
if (getRandomBytes(this->OutputLoc + 16, 16))
error("entropy source failure");
}
template <class ELFT>
BuildIdHexstring<ELFT>::BuildIdHexstring()
: BuildIdSection<ELFT>(Config->BuildIdVector.size()) {}
template <class ELFT>
void BuildIdHexstring<ELFT>::writeBuildId(ArrayRef<uint8_t> Buf) {
memcpy(this->OutputLoc + 16, Config->BuildIdVector.data(),
Config->BuildIdVector.size());
}
template class elf::InputSectionBase<ELF32LE>;
template class elf::InputSectionBase<ELF32BE>;
template class elf::InputSectionBase<ELF64LE>;
@ -882,3 +941,33 @@ template class elf::MipsAbiFlagsInputSection<ELF32LE>;
template class elf::MipsAbiFlagsInputSection<ELF32BE>;
template class elf::MipsAbiFlagsInputSection<ELF64LE>;
template class elf::MipsAbiFlagsInputSection<ELF64BE>;
template class elf::BuildIdSection<ELF32LE>;
template class elf::BuildIdSection<ELF32BE>;
template class elf::BuildIdSection<ELF64LE>;
template class elf::BuildIdSection<ELF64BE>;
template class elf::BuildIdFastHash<ELF32LE>;
template class elf::BuildIdFastHash<ELF32BE>;
template class elf::BuildIdFastHash<ELF64LE>;
template class elf::BuildIdFastHash<ELF64BE>;
template class elf::BuildIdMd5<ELF32LE>;
template class elf::BuildIdMd5<ELF32BE>;
template class elf::BuildIdMd5<ELF64LE>;
template class elf::BuildIdMd5<ELF64BE>;
template class elf::BuildIdSha1<ELF32LE>;
template class elf::BuildIdSha1<ELF32BE>;
template class elf::BuildIdSha1<ELF64LE>;
template class elf::BuildIdSha1<ELF64BE>;
template class elf::BuildIdUuid<ELF32LE>;
template class elf::BuildIdUuid<ELF32BE>;
template class elf::BuildIdUuid<ELF64LE>;
template class elf::BuildIdUuid<ELF64BE>;
template class elf::BuildIdHexstring<ELF32LE>;
template class elf::BuildIdHexstring<ELF32BE>;
template class elf::BuildIdHexstring<ELF64LE>;
template class elf::BuildIdHexstring<ELF64BE>;

55
lld/ELF/InputSection.h
View File

@ -252,6 +252,9 @@ public:
// to. The writer sets a value.
uint64_t OutSecOff = 0;
// Location of this section in the output buffer
uint8_t *OutputLoc = nullptr;
// InputSection that is dependent on us (reverse dependency for GC)
InputSectionBase<ELFT> *DependentSection = nullptr;
@ -339,6 +342,58 @@ public:
const llvm::object::Elf_Mips_ABIFlags<ELFT> *Flags = nullptr;
};
template <class ELFT> class BuildIdSection : public InputSection<ELFT> {
typedef OutputSectionBase<ELFT> Base;
public:
virtual void writeBuildId(ArrayRef<uint8_t> Buf) = 0;
virtual ~BuildIdSection() = default;
protected:
BuildIdSection(size_t HashSize);
std::vector<uint8_t> Buf;
};
template <class ELFT>
class BuildIdFastHash final : public BuildIdSection<ELFT> {
public:
BuildIdFastHash() : BuildIdSection<ELFT>(8) {}
void writeBuildId(ArrayRef<uint8_t> Buf) override;
};
template <class ELFT> class BuildIdMd5 final : public BuildIdSection<ELFT> {
public:
BuildIdMd5() : BuildIdSection<ELFT>(16) {}
void writeBuildId(ArrayRef<uint8_t> Buf) override;
};
template <class ELFT> class BuildIdSha1 final : public BuildIdSection<ELFT> {
public:
BuildIdSha1() : BuildIdSection<ELFT>(20) {}
void writeBuildId(ArrayRef<uint8_t> Buf) override;
};
template <class ELFT> class BuildIdUuid final : public BuildIdSection<ELFT> {
public:
BuildIdUuid() : BuildIdSection<ELFT>(16) {}
void writeBuildId(ArrayRef<uint8_t> Buf) override;
};
template <class ELFT>
class BuildIdHexstring final : public BuildIdSection<ELFT> {
public:
BuildIdHexstring();
void writeBuildId(ArrayRef<uint8_t>) override;
};
// Linker generated sections which can be used as inputs.
template <class ELFT> struct In {
static BuildIdSection<ELFT> *BuildId;
static std::vector<InputSection<ELFT> *> Sections;
};
template <class ELFT> BuildIdSection<ELFT> *In<ELFT>::BuildId;
template <class ELFT> std::vector<InputSection<ELFT> *> In<ELFT>::Sections;
} // namespace elf
} // namespace lld

90
lld/ELF/OutputSections.cpp
View File

@ -19,9 +19,7 @@
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/MD5.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/RandomNumberGenerator.h"
#include "llvm/Support/SHA1.h"
#include "llvm/Support/xxhash.h"
using namespace llvm;
using namespace llvm::dwarf;
@ -1738,64 +1736,6 @@ template <class ELFT> void VersionNeedSection<ELFT>::finalize() {
this->Header.sh_size = Size;
}
template <class ELFT>
BuildIdSection<ELFT>::BuildIdSection(size_t HashSize)
: OutputSectionBase<ELFT>(".note.gnu.build-id", SHT_NOTE, SHF_ALLOC),
HashSize(HashSize) {
// 16 bytes for the note section header.
this->Header.sh_size = 16 + HashSize;
}
template <class ELFT> void BuildIdSection<ELFT>::writeTo(uint8_t *Buf) {
const endianness E = ELFT::TargetEndianness;
write32<E>(Buf, 4); // Name size
write32<E>(Buf + 4, HashSize); // Content size
write32<E>(Buf + 8, NT_GNU_BUILD_ID); // Type
memcpy(Buf + 12, "GNU", 4); // Name string
HashBuf = Buf + 16;
}
template <class ELFT>
void BuildIdFastHash<ELFT>::writeBuildId(ArrayRef<uint8_t> Buf) {
const endianness E = ELFT::TargetEndianness;
// 64-bit xxhash
uint64_t Hash = xxHash64(toStringRef(Buf));
write64<E>(this->HashBuf, Hash);
}
template <class ELFT>
void BuildIdMd5<ELFT>::writeBuildId(ArrayRef<uint8_t> Buf) {
MD5 Hash;
Hash.update(Buf);
MD5::MD5Result Res;
Hash.final(Res);
memcpy(this->HashBuf, Res, 16);
}
template <class ELFT>
void BuildIdSha1<ELFT>::writeBuildId(ArrayRef<uint8_t> Buf) {
SHA1 Hash;
Hash.update(Buf);
memcpy(this->HashBuf, Hash.final().data(), 20);
}
template <class ELFT>
void BuildIdUuid<ELFT>::writeBuildId(ArrayRef<uint8_t> Buf) {
if (getRandomBytes(this->HashBuf, 16))
error("entropy source failure");
}
template <class ELFT>
BuildIdHexstring<ELFT>::BuildIdHexstring()
: BuildIdSection<ELFT>(Config->BuildIdVector.size()) {}
template <class ELFT>
void BuildIdHexstring<ELFT>::writeBuildId(ArrayRef<uint8_t> Buf) {
memcpy(this->HashBuf, Config->BuildIdVector.data(),
Config->BuildIdVector.size());
}
template <class ELFT>
MipsReginfoOutputSection<ELFT>::MipsReginfoOutputSection()
: OutputSectionBase<ELFT>(".reginfo", SHT_MIPS_REGINFO, SHF_ALLOC) {
@ -2101,36 +2041,6 @@ template class VersionDefinitionSection<ELF32BE>;
template class VersionDefinitionSection<ELF64LE>;
template class VersionDefinitionSection<ELF64BE>;
template class BuildIdSection<ELF32LE>;
template class BuildIdSection<ELF32BE>;
template class BuildIdSection<ELF64LE>;
template class BuildIdSection<ELF64BE>;
template class BuildIdFastHash<ELF32LE>;
template class BuildIdFastHash<ELF32BE>;
template class BuildIdFastHash<ELF64LE>;
template class BuildIdFastHash<ELF64BE>;
template class BuildIdMd5<ELF32LE>;
template class BuildIdMd5<ELF32BE>;
template class BuildIdMd5<ELF64LE>;
template class BuildIdMd5<ELF64BE>;
template class BuildIdSha1<ELF32LE>;
template class BuildIdSha1<ELF32BE>;
template class BuildIdSha1<ELF64LE>;
template class BuildIdSha1<ELF64BE>;
template class BuildIdUuid<ELF32LE>;
template class BuildIdUuid<ELF32BE>;
template class BuildIdUuid<ELF64LE>;
template class BuildIdUuid<ELF64BE>;
template class BuildIdHexstring<ELF32LE>;
template class BuildIdHexstring<ELF32BE>;
template class BuildIdHexstring<ELF64LE>;
template class BuildIdHexstring<ELF64BE>;
template class GdbIndexSection<ELF32LE>;
template class GdbIndexSection<ELF32BE>;
template class GdbIndexSection<ELF64LE>;

50
lld/ELF/OutputSections.h
View File

@ -51,7 +51,6 @@ public:
typedef typename ELFT::Shdr Elf_Shdr;
enum Kind {
Base,
BuildId,
Dynamic,
EHFrame,
EHFrameHdr,
@ -738,60 +737,12 @@ private:
std::vector<FdeData> Fdes;
};
template <class ELFT> class BuildIdSection : public OutputSectionBase<ELFT> {
typedef OutputSectionBase<ELFT> Base;
public:
void writeTo(uint8_t *Buf) override;
virtual void writeBuildId(ArrayRef<uint8_t> Buf) = 0;
typename Base::Kind getKind() const override { return Base::BuildId; }
static bool classof(const Base *B) { return B->getKind() == Base::BuildId; }
protected:
BuildIdSection(size_t HashSize);
size_t HashSize;
uint8_t *HashBuf = nullptr;
};
template <class ELFT>
class BuildIdFastHash final : public BuildIdSection<ELFT> {
public:
BuildIdFastHash() : BuildIdSection<ELFT>(8) {}
void writeBuildId(ArrayRef<uint8_t> Buf) override;
};
template <class ELFT> class BuildIdMd5 final : public BuildIdSection<ELFT> {
public:
BuildIdMd5() : BuildIdSection<ELFT>(16) {}
void writeBuildId(ArrayRef<uint8_t> Buf) override;
};
template <class ELFT> class BuildIdSha1 final : public BuildIdSection<ELFT> {
public:
BuildIdSha1() : BuildIdSection<ELFT>(20) {}
void writeBuildId(ArrayRef<uint8_t> Buf) override;
};
template <class ELFT> class BuildIdUuid final : public BuildIdSection<ELFT> {
public:
BuildIdUuid() : BuildIdSection<ELFT>(16) {}
void writeBuildId(ArrayRef<uint8_t> Buf) override;
};
template <class ELFT>
class BuildIdHexstring final : public BuildIdSection<ELFT> {
public:
BuildIdHexstring();
void writeBuildId(ArrayRef<uint8_t>) override;
};
// All output sections that are hadnled by the linker specially are
// globally accessible. Writer initializes them, so don't use them
// until Writer is initialized.
template <class ELFT> struct Out {
typedef typename ELFT::uint uintX_t;
typedef typename ELFT::Phdr Elf_Phdr;
static BuildIdSection<ELFT> *BuildId;
static DynamicSection<ELFT> *Dynamic;
static EhFrameHeader<ELFT> *EhFrameHdr;
static EhOutputSection<ELFT> *EhFrame;
@ -862,7 +813,6 @@ template <class ELFT> uint64_t getHeaderSize() {
return Out<ELFT>::ElfHeader->getSize() + Out<ELFT>::ProgramHeaders->getSize();
}
template <class ELFT> BuildIdSection<ELFT> *Out<ELFT>::BuildId;
template <class ELFT> DynamicSection<ELFT> *Out<ELFT>::Dynamic;
template <class ELFT> EhFrameHeader<ELFT> *Out<ELFT>::EhFrameHdr;
template <class ELFT> EhOutputSection<ELFT> *Out<ELFT>::EhFrame;

59
lld/ELF/Writer.cpp
View File

@ -50,6 +50,7 @@ private:
void copyLocalSymbols();
void addReservedSymbols();
void addInputSec(InputSectionBase<ELFT> *S);
void createSections();
void forEachRelSec(std::function<void(InputSectionBase<ELFT> &,
const typename ELFT::Shdr &)> Fn);
@ -209,7 +210,6 @@ template <class ELFT> void elf::writeResult() {
VerDef.reset(new VersionDefinitionSection<ELFT>());
Out<ELFT>::Bss = &Bss;
Out<ELFT>::BuildId = BuildId.get();
Out<ELFT>::DynStrTab = DynStrTab.get();
Out<ELFT>::DynSymTab = DynSymTab.get();
Out<ELFT>::Dynamic = &Dynamic;
@ -241,6 +241,10 @@ template <class ELFT> void elf::writeResult() {
Out<ELFT>::InitArray = nullptr;
Out<ELFT>::FiniArray = nullptr;
// Initialize linker generated sections
In<ELFT>::BuildId = BuildId.get();
In<ELFT>::Sections = {BuildId.get()};
Writer<ELFT>().run();
Out<ELFT>::Pool.clear();
}
@ -696,28 +700,29 @@ void Writer<ELFT>::forEachRelSec(
}
}
template <class ELFT> void Writer<ELFT>::createSections() {
auto Add = [&](InputSectionBase<ELFT> *IS) {
if (isDiscarded(IS)) {
reportDiscarded(IS);
return;
}
OutputSectionBase<ELFT> *Sec;
bool IsNew;
StringRef OutsecName = getOutputSectionName(IS->Name);
std::tie(Sec, IsNew) = Factory.create(IS, OutsecName);
if (IsNew)
OutputSections.push_back(Sec);
Sec->addSection(IS);
};
template <class ELFT>
void Writer<ELFT>::addInputSec(InputSectionBase<ELFT> *IS) {
if (isDiscarded(IS)) {
reportDiscarded(IS);
return;
}
OutputSectionBase<ELFT> *Sec;
bool IsNew;
StringRef OutsecName = getOutputSectionName(IS->Name);
std::tie(Sec, IsNew) = Factory.create(IS, OutsecName);
if (IsNew)
OutputSections.push_back(Sec);
Sec->addSection(IS);
}
template <class ELFT> void Writer<ELFT>::createSections() {
for (elf::ObjectFile<ELFT> *F : Symtab<ELFT>::X->getObjectFiles())
for (InputSectionBase<ELFT> *IS : F->getSections())
Add(IS);
addInputSec(IS);
for (BinaryFile *F : Symtab<ELFT>::X->getBinaryFiles())
for (InputSectionData *ID : F->getSections())
Add(cast<InputSection<ELFT>>(ID));
addInputSec(cast<InputSection<ELFT>>(ID));
sortInitFini(findSection(".init_array"));
sortInitFini(findSection(".fini_array"));
@ -847,6 +852,11 @@ template <class ELFT> void Writer<ELFT>::finalizeSections() {
// This function adds linker-created Out<ELFT>::* sections.
addPredefinedSections();
// Adds linker generated input sections to
// corresponding output sections.
for (InputSection<ELFT> *S : In<ELFT>::Sections)
addInputSec(S);
sortSections();
unsigned I = 1;
@ -855,6 +865,11 @@ template <class ELFT> void Writer<ELFT>::finalizeSections() {
Sec->setSHName(Out<ELFT>::ShStrTab->addString(Sec->getName()));
}
// Finalize linker generated sections.
for (InputSection<ELFT> *S : In<ELFT>::Sections)
if (S && S->OutSec)
S->OutSec->assignOffsets();
// Finalizers fix each section's size.
// .dynsym is finalized early since that may fill up .gnu.hash.
if (Out<ELFT>::DynSymTab)
@ -899,12 +914,6 @@ template <class ELFT> void Writer<ELFT>::addPredefinedSections() {
OutputSections.push_back(OS);
};
// A core file does not usually contain unmodified segments except
// the first page of the executable. Add the build ID section to beginning of
// the file so that the section is included in the first page.
if (Out<ELFT>::BuildId)
OutputSections.insert(OutputSections.begin(), Out<ELFT>::BuildId);
// Add .interp at first because some loaders want to see that section
// on the first page of the executable file when loaded into memory.
if (Out<ELFT>::Interp)
@ -1484,13 +1493,13 @@ template <class ELFT> void Writer<ELFT>::writeSections() {
}
template <class ELFT> void Writer<ELFT>::writeBuildId() {
if (!Out<ELFT>::BuildId)
if (!In<ELFT>::BuildId || !In<ELFT>::BuildId->OutSec)
return;
// Compute a hash of all sections of the output file.
uint8_t *Start = Buffer->getBufferStart();
uint8_t *End = Start + FileSize;
Out<ELFT>::BuildId->writeBuildId({Start, End});
In<ELFT>::BuildId->writeBuildId({Start, End});
}
template void elf::writeResult<ELF32LE>();

2
lld/test/ELF/build-id.s
View File

@ -23,9 +23,9 @@ _start:
.section .note.test, "a", @note
.quad 42
# DEFAULT: Contents of section .note.test:
# DEFAULT: Contents of section .note.gnu.build-id:
# DEFAULT-NEXT: 04000000 08000000 03000000 474e5500 ............GNU.
# DEFAULT: Contents of section .note.test:
# MD5: Contents of section .note.gnu.build-id:
# MD5-NEXT: 04000000 10000000 03000000 474e5500 ............GNU.