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[COFF] Simplify Chunk::writeTo and remove OutputSectionOff, NFC

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Summary:
Prior to this change, every implementation of writeTo would add
OutputSectionOff to the output section buffer start before writing data.
Instead, do this math in the caller, so that it can be written once
instead of many times.

The output section offset is always equivalent to the difference between
the chunk RVA and the output section RVA, so we can replace the one
remaining usage of OutputSectionOff with that subtraction.

This doesn't change the size of SectionChunk because of alignment
requirements, but I will rearrange the fields in a follow-up change to
accomplish that.

Reviewers: ruiu, aganea

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61696

llvm-svn: 360376
This commit is contained in:
Reid Kleckner 2019-05-09 21:21:22 +00:00
parent df225764b7
commit 4c64256b51
5 changed files with 78 additions and 83 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

53
lld/COFF/Chunks.cpp
View File

@ -344,7 +344,7 @@ void SectionChunk::writeTo(uint8_t *Buf) const {
// Copy section contents from source object file to output file.
ArrayRef<uint8_t> A = getContents();
if (!A.empty())
memcpy(Buf + OutputSectionOff, A.data(), A.size());
memcpy(Buf, A.data(), A.size());
// Apply relocations.
size_t InputSize = getSize();
@ -360,7 +360,7 @@ void SectionChunk::writeTo(uint8_t *Buf) const {
continue;
}
uint8_t *Off = Buf + OutputSectionOff + Rel.VirtualAddress;
uint8_t *Off = Buf + Rel.VirtualAddress;
auto *Sym =
dyn_cast_or_null<Defined>(File->getSymbol(Rel.SymbolTableIndex));
@ -649,8 +649,8 @@ uint32_t CommonChunk::getOutputCharacteristics() const {
}
void StringChunk::writeTo(uint8_t *Buf) const {
memcpy(Buf + OutputSectionOff, Str.data(), Str.size());
Buf[OutputSectionOff + Str.size()] = '\0';
memcpy(Buf, Str.data(), Str.size());
Buf[Str.size()] = '\0';
}
ImportThunkChunkX64::ImportThunkChunkX64(Defined *S) : ImpSymbol(S) {
@ -660,9 +660,9 @@ ImportThunkChunkX64::ImportThunkChunkX64(Defined *S) : ImpSymbol(S) {
}
void ImportThunkChunkX64::writeTo(uint8_t *Buf) const {
memcpy(Buf + OutputSectionOff, ImportThunkX86, sizeof(ImportThunkX86));
memcpy(Buf, ImportThunkX86, sizeof(ImportThunkX86));
// The first two bytes is a JMP instruction. Fill its operand.
write32le(Buf + OutputSectionOff + 2, ImpSymbol->getRVA() - RVA - getSize());
write32le(Buf + 2, ImpSymbol->getRVA() - RVA - getSize());
}
void ImportThunkChunkX86::getBaserels(std::vector<Baserel> *Res) {
@ -670,9 +670,9 @@ void ImportThunkChunkX86::getBaserels(std::vector<Baserel> *Res) {
}
void ImportThunkChunkX86::writeTo(uint8_t *Buf) const {
memcpy(Buf + OutputSectionOff, ImportThunkX86, sizeof(ImportThunkX86));
memcpy(Buf, ImportThunkX86, sizeof(ImportThunkX86));
// The first two bytes is a JMP instruction. Fill its operand.
write32le(Buf + OutputSectionOff + 2,
write32le(Buf + 2,
ImpSymbol->getRVA() + Config->ImageBase);
}
@ -681,16 +681,16 @@ void ImportThunkChunkARM::getBaserels(std::vector<Baserel> *Res) {
}
void ImportThunkChunkARM::writeTo(uint8_t *Buf) const {
memcpy(Buf + OutputSectionOff, ImportThunkARM, sizeof(ImportThunkARM));
memcpy(Buf, ImportThunkARM, sizeof(ImportThunkARM));
// Fix mov.w and mov.t operands.
applyMOV32T(Buf + OutputSectionOff, ImpSymbol->getRVA() + Config->ImageBase);
applyMOV32T(Buf, ImpSymbol->getRVA() + Config->ImageBase);
}
void ImportThunkChunkARM64::writeTo(uint8_t *Buf) const {
int64_t Off = ImpSymbol->getRVA() & 0xfff;
memcpy(Buf + OutputSectionOff, ImportThunkARM64, sizeof(ImportThunkARM64));
applyArm64Addr(Buf + OutputSectionOff, ImpSymbol->getRVA(), RVA, 12);
applyArm64Ldr(Buf + OutputSectionOff + 4, Off);
memcpy(Buf, ImportThunkARM64, sizeof(ImportThunkARM64));
applyArm64Addr(Buf, ImpSymbol->getRVA(), RVA, 12);
applyArm64Ldr(Buf + 4, Off);
}
// A Thumb2, PIC, non-interworking range extension thunk.
@ -708,8 +708,8 @@ size_t RangeExtensionThunkARM::getSize() const {
void RangeExtensionThunkARM::writeTo(uint8_t *Buf) const {
assert(Config->Machine == ARMNT);
uint64_t Offset = Target->getRVA() - RVA - 12;
memcpy(Buf + OutputSectionOff, ArmThunk, sizeof(ArmThunk));
applyMOV32T(Buf + OutputSectionOff, uint32_t(Offset));
memcpy(Buf, ArmThunk, sizeof(ArmThunk));
applyMOV32T(Buf, uint32_t(Offset));
}
// A position independent ARM64 adrp+add thunk, with a maximum range of
@ -727,9 +727,9 @@ size_t RangeExtensionThunkARM64::getSize() const {
void RangeExtensionThunkARM64::writeTo(uint8_t *Buf) const {
assert(Config->Machine == ARM64);
memcpy(Buf + OutputSectionOff, Arm64Thunk, sizeof(Arm64Thunk));
applyArm64Addr(Buf + OutputSectionOff + 0, Target->getRVA(), RVA, 12);
applyArm64Imm(Buf + OutputSectionOff + 4, Target->getRVA() & 0xfff, 0);
memcpy(Buf, Arm64Thunk, sizeof(Arm64Thunk));
applyArm64Addr(Buf + 0, Target->getRVA(), RVA, 12);
applyArm64Imm(Buf + 4, Target->getRVA() & 0xfff, 0);
}
void LocalImportChunk::getBaserels(std::vector<Baserel> *Res) {
@ -740,14 +740,14 @@ size_t LocalImportChunk::getSize() const { return Config->Wordsize; }
void LocalImportChunk::writeTo(uint8_t *Buf) const {
if (Config->is64()) {
write64le(Buf + OutputSectionOff, Sym->getRVA() + Config->ImageBase);
write64le(Buf, Sym->getRVA() + Config->ImageBase);
} else {
write32le(Buf + OutputSectionOff, Sym->getRVA() + Config->ImageBase);
write32le(Buf, Sym->getRVA() + Config->ImageBase);
}
}
void RVATableChunk::writeTo(uint8_t *Buf) const {
ulittle32_t *Begin = reinterpret_cast<ulittle32_t *>(Buf + OutputSectionOff);
ulittle32_t *Begin = reinterpret_cast<ulittle32_t *>(Buf);
size_t Cnt = 0;
for (const ChunkAndOffset &CO : Syms)
Begin[Cnt++] = CO.InputChunk->getRVA() + CO.Offset;
@ -768,7 +768,7 @@ void PseudoRelocTableChunk::writeTo(uint8_t *Buf) const {
if (Relocs.empty())
return;
ulittle32_t *Table = reinterpret_cast<ulittle32_t *>(Buf + OutputSectionOff);
ulittle32_t *Table = reinterpret_cast<ulittle32_t *>(Buf);
// This is the list header, to signal the runtime pseudo relocation v2
// format.
Table[0] = 0;
@ -838,7 +838,7 @@ BaserelChunk::BaserelChunk(uint32_t Page, Baserel *Begin, Baserel *End) {
}
void BaserelChunk::writeTo(uint8_t *Buf) const {
memcpy(Buf + OutputSectionOff, Data.data(), Data.size());
memcpy(Buf, Data.data(), Data.size());
}
uint8_t Baserel::getDefaultType() {
@ -883,7 +883,6 @@ void MergeChunk::finalizeContents() {
size_t Off = Builder.getOffset(toStringRef(C->getContents()));
C->setOutputSection(Out);
C->setRVA(RVA + Off);
C->OutputSectionOff = OutputSectionOff + Off;
}
}
@ -896,7 +895,7 @@ size_t MergeChunk::getSize() const {
}
void MergeChunk::writeTo(uint8_t *Buf) const {
Builder.write(Buf + OutputSectionOff);
Builder.write(Buf);
}
// MinGW specific.
@ -904,9 +903,9 @@ size_t AbsolutePointerChunk::getSize() const { return Config->Wordsize; }
void AbsolutePointerChunk::writeTo(uint8_t *Buf) const {
if (Config->is64()) {
write64le(Buf + OutputSectionOff, Value);
write64le(Buf, Value);
} else {
write32le(Buf + OutputSectionOff, Value);
write32le(Buf, Value);
}
}

4
lld/COFF/Chunks.h
View File

@ -121,10 +121,6 @@ protected:
// The RVA of this chunk in the output. The writer sets a value.
uint32_t RVA = 0;
public:
// The offset from beginning of the output section. The writer sets a value.
uint32_t OutputSectionOff = 0;
protected:
// The output section for this chunk.
OutputSection *Out = nullptr;

83
lld/COFF/DLL.cpp
View File

@ -46,9 +46,9 @@ public:
}
void writeTo(uint8_t *Buf) const override {
memset(Buf + OutputSectionOff, 0, getSize());
write16le(Buf + OutputSectionOff, Hint);
memcpy(Buf + OutputSectionOff + 2, Name.data(), Name.size());
memset(Buf, 0, getSize());
write16le(Buf, Hint);
memcpy(Buf + 2, Name.data(), Name.size());
}
private:
@ -64,9 +64,9 @@ public:
void writeTo(uint8_t *Buf) const override {
if (Config->is64())
write64le(Buf + OutputSectionOff, HintName->getRVA());
write64le(Buf, HintName->getRVA());
else
write32le(Buf + OutputSectionOff, HintName->getRVA());
write32le(Buf, HintName->getRVA());
}
Chunk *HintName;
@ -86,9 +86,9 @@ public:
// An import-by-ordinal slot has MSB 1 to indicate that
// this is import-by-ordinal (and not import-by-name).
if (Config->is64()) {
write64le(Buf + OutputSectionOff, (1ULL << 63) | Ordinal);
write64le(Buf, (1ULL << 63) | Ordinal);
} else {
write32le(Buf + OutputSectionOff, (1ULL << 31) | Ordinal);
write32le(Buf, (1ULL << 31) | Ordinal);
}
}
@ -102,9 +102,9 @@ public:
size_t getSize() const override { return sizeof(ImportDirectoryTableEntry); }
void writeTo(uint8_t *Buf) const override {
memset(Buf + OutputSectionOff, 0, getSize());
memset(Buf, 0, getSize());
auto *E = (coff_import_directory_table_entry *)(Buf + OutputSectionOff);
auto *E = (coff_import_directory_table_entry *)(Buf);
E->ImportLookupTableRVA = LookupTab->getRVA();
E->NameRVA = DLLName->getRVA();
E->ImportAddressTableRVA = AddressTab->getRVA();
@ -124,7 +124,7 @@ public:
size_t getSize() const override { return Size; }
void writeTo(uint8_t *Buf) const override {
memset(Buf + OutputSectionOff, 0, Size);
memset(Buf, 0, Size);
}
private:
@ -169,9 +169,9 @@ public:
}
void writeTo(uint8_t *Buf) const override {
memset(Buf + OutputSectionOff, 0, getSize());
memset(Buf, 0, getSize());
auto *E = (delay_import_directory_table_entry *)(Buf + OutputSectionOff);
auto *E = (delay_import_directory_table_entry *)(Buf);
E->Attributes = 1;
E->Name = DLLName->getRVA();
E->ModuleHandle = ModuleHandle->getRVA();
@ -280,10 +280,10 @@ public:
size_t getSize() const override { return sizeof(ThunkX64); }
void writeTo(uint8_t *Buf) const override {
memcpy(Buf + OutputSectionOff, ThunkX64, sizeof(ThunkX64));
write32le(Buf + OutputSectionOff + 36, Imp->getRVA() - RVA - 40);
write32le(Buf + OutputSectionOff + 43, Desc->getRVA() - RVA - 47);
write32le(Buf + OutputSectionOff + 48, Helper->getRVA() - RVA - 52);
memcpy(Buf, ThunkX64, sizeof(ThunkX64));
write32le(Buf + 36, Imp->getRVA() - RVA - 40);
write32le(Buf + 43, Desc->getRVA() - RVA - 47);
write32le(Buf + 48, Helper->getRVA() - RVA - 52);
}
Defined *Imp = nullptr;
@ -299,10 +299,10 @@ public:
size_t getSize() const override { return sizeof(ThunkX86); }
void writeTo(uint8_t *Buf) const override {
memcpy(Buf + OutputSectionOff, ThunkX86, sizeof(ThunkX86));
write32le(Buf + OutputSectionOff + 3, Imp->getRVA() + Config->ImageBase);
write32le(Buf + OutputSectionOff + 8, Desc->getRVA() + Config->ImageBase);
write32le(Buf + OutputSectionOff + 13, Helper->getRVA() - RVA - 17);
memcpy(Buf, ThunkX86, sizeof(ThunkX86));
write32le(Buf + 3, Imp->getRVA() + Config->ImageBase);
write32le(Buf + 8, Desc->getRVA() + Config->ImageBase);
write32le(Buf + 13, Helper->getRVA() - RVA - 17);
}
void getBaserels(std::vector<Baserel> *Res) override {
@ -323,10 +323,10 @@ public:
size_t getSize() const override { return sizeof(ThunkARM); }
void writeTo(uint8_t *Buf) const override {
memcpy(Buf + OutputSectionOff, ThunkARM, sizeof(ThunkARM));
applyMOV32T(Buf + OutputSectionOff + 0, Imp->getRVA() + Config->ImageBase);
applyMOV32T(Buf + OutputSectionOff + 22, Desc->getRVA() + Config->ImageBase);
applyBranch24T(Buf + OutputSectionOff + 30, Helper->getRVA() - RVA - 34);
memcpy(Buf, ThunkARM, sizeof(ThunkARM));
applyMOV32T(Buf + 0, Imp->getRVA() + Config->ImageBase);
applyMOV32T(Buf + 22, Desc->getRVA() + Config->ImageBase);
applyBranch24T(Buf + 30, Helper->getRVA() - RVA - 34);
}
void getBaserels(std::vector<Baserel> *Res) override {
@ -347,13 +347,12 @@ public:
size_t getSize() const override { return sizeof(ThunkARM64); }
void writeTo(uint8_t *Buf) const override {
memcpy(Buf + OutputSectionOff, ThunkARM64, sizeof(ThunkARM64));
applyArm64Addr(Buf + OutputSectionOff + 0, Imp->getRVA(), RVA + 0, 12);
applyArm64Imm(Buf + OutputSectionOff + 4, Imp->getRVA() & 0xfff, 0);
applyArm64Addr(Buf + OutputSectionOff + 52, Desc->getRVA(), RVA + 52, 12);
applyArm64Imm(Buf + OutputSectionOff + 56, Desc->getRVA() & 0xfff, 0);
applyArm64Branch26(Buf + OutputSectionOff + 60,
Helper->getRVA() - RVA - 60);
memcpy(Buf, ThunkARM64, sizeof(ThunkARM64));
applyArm64Addr(Buf + 0, Imp->getRVA(), RVA + 0, 12);
applyArm64Imm(Buf + 4, Imp->getRVA() & 0xfff, 0);
applyArm64Addr(Buf + 52, Desc->getRVA(), RVA + 52, 12);
applyArm64Imm(Buf + 56, Desc->getRVA() & 0xfff, 0);
applyArm64Branch26(Buf + 60, Helper->getRVA() - RVA - 60);
}
Defined *Imp = nullptr;
@ -371,13 +370,13 @@ public:
void writeTo(uint8_t *Buf) const override {
if (Config->is64()) {
write64le(Buf + OutputSectionOff, Thunk->getRVA() + Config->ImageBase);
write64le(Buf, Thunk->getRVA() + Config->ImageBase);
} else {
uint32_t Bit = 0;
// Pointer to thumb code must have the LSB set, so adjust it.
if (Config->Machine == ARMNT)
Bit = 1;
write32le(Buf + OutputSectionOff, (Thunk->getRVA() + Config->ImageBase) | Bit);
write32le(Buf, (Thunk->getRVA() + Config->ImageBase) | Bit);
}
}
@ -403,9 +402,9 @@ public:
}
void writeTo(uint8_t *Buf) const override {
memset(Buf + OutputSectionOff, 0, getSize());
memset(Buf, 0, getSize());
auto *E = (export_directory_table_entry *)(Buf + OutputSectionOff);
auto *E = (export_directory_table_entry *)(Buf);
E->NameRVA = DLLName->getRVA();
E->OrdinalBase = 0;
E->AddressTableEntries = MaxOrdinal + 1;
@ -429,10 +428,10 @@ public:
size_t getSize() const override { return Size * 4; }
void writeTo(uint8_t *Buf) const override {
memset(Buf + OutputSectionOff, 0, getSize());
memset(Buf, 0, getSize());
for (const Export &E : Config->Exports) {
uint8_t *P = Buf + OutputSectionOff + E.Ordinal * 4;
uint8_t *P = Buf + E.Ordinal * 4;
uint32_t Bit = 0;
// Pointer to thumb code must have the LSB set, so adjust it.
if (Config->Machine == ARMNT && !E.Data)
@ -455,10 +454,9 @@ public:
size_t getSize() const override { return Chunks.size() * 4; }
void writeTo(uint8_t *Buf) const override {
uint8_t *P = Buf + OutputSectionOff;
for (Chunk *C : Chunks) {
write32le(P, C->getRVA());
P += 4;
write32le(Buf, C->getRVA());
Buf += 4;
}
}
@ -472,12 +470,11 @@ public:
size_t getSize() const override { return Size * 2; }
void writeTo(uint8_t *Buf) const override {
uint8_t *P = Buf + OutputSectionOff;
for (Export &E : Config->Exports) {
if (E.Noname)
continue;
write16le(P, E.Ordinal);
P += 2;
write16le(Buf, E.Ordinal);
Buf += 2;
}
}

10
lld/COFF/PDB.cpp
View File

@ -1030,7 +1030,7 @@ void PDBLinker::mergeSymbolRecords(ObjFile *File, const CVIndexMap &IndexMap,
static ArrayRef<uint8_t> relocateDebugChunk(BumpPtrAllocator &Alloc,
SectionChunk &DebugChunk) {
uint8_t *Buffer = Alloc.Allocate<uint8_t>(DebugChunk.getSize());
assert(DebugChunk.OutputSectionOff == 0 &&
assert(DebugChunk.getOutputSection() == nullptr &&
"debug sections should not be in output sections");
DebugChunk.writeTo(Buffer);
return makeArrayRef(Buffer, DebugChunk.getSize());
@ -1557,6 +1557,8 @@ void PDBLinker::addImportFilesToPDB(ArrayRef<OutputSection *> OutputSections) {
}
DefinedImportThunk *Thunk = cast<DefinedImportThunk>(File->ThunkSym);
Chunk *ThunkChunk = Thunk->getChunk();
OutputSection *ThunkOS = ThunkChunk->getOutputSection();
ObjNameSym ONS(SymbolRecordKind::ObjNameSym);
Compile3Sym CS(SymbolRecordKind::Compile3Sym);
@ -1573,9 +1575,9 @@ void PDBLinker::addImportFilesToPDB(ArrayRef<OutputSection *> OutputSections) {
TS.End = 0;
TS.Next = 0;
TS.Thunk = ThunkOrdinal::Standard;
TS.Length = Thunk->getChunk()->getSize();
TS.Segment = Thunk->getChunk()->getOutputSection()->SectionIndex;
TS.Offset = Thunk->getChunk()->OutputSectionOff;
TS.Length = ThunkChunk->getSize();
TS.Segment = ThunkOS->SectionIndex;
TS.Offset = ThunkChunk->getRVA() - ThunkOS->getRVA();
Mod->addSymbol(codeview::SymbolSerializer::writeOneSymbol(
ONS, Alloc, CodeViewContainer::Pdb));

11
lld/COFF/Writer.cpp
View File

@ -91,7 +91,7 @@ public:
}
void writeTo(uint8_t *B) const override {
auto *D = reinterpret_cast<debug_directory *>(B + OutputSectionOff);
auto *D = reinterpret_cast<debug_directory *>(B);
for (const Chunk *Record : Records) {
OutputSection *OS = Record->getOutputSection();
@ -145,10 +145,10 @@ public:
void writeTo(uint8_t *B) const override {
// Save off the DebugInfo entry to backfill the file signature (build id)
// in Writer::writeBuildId
BuildId = reinterpret_cast<codeview::DebugInfo *>(B + OutputSectionOff);
BuildId = reinterpret_cast<codeview::DebugInfo *>(B);
// variable sized field (PDB Path)
char *P = reinterpret_cast<char *>(B + OutputSectionOff + sizeof(*BuildId));
char *P = reinterpret_cast<char *>(B + sizeof(*BuildId));
if (!Config->PDBAltPath.empty())
memcpy(P, Config->PDBAltPath.data(), Config->PDBAltPath.size());
P[Config->PDBAltPath.size()] = '\0';
@ -1161,7 +1161,6 @@ void Writer::assignAddresses() {
VirtualSize += Padding;
VirtualSize = alignTo(VirtualSize, C->Alignment);
C->setRVA(RVA + VirtualSize);
C->OutputSectionOff = VirtualSize;
C->finalizeContents();
VirtualSize += C->getSize();
if (C->hasData())
@ -1675,7 +1674,9 @@ void Writer::writeSections() {
// ADD instructions).
if (Sec->Header.Characteristics & IMAGE_SCN_CNT_CODE)
memset(SecBuf, 0xCC, Sec->getRawSize());
parallelForEach(Sec->Chunks, [&](Chunk *C) { C->writeTo(SecBuf); });
parallelForEach(Sec->Chunks, [&](Chunk *C) {
C->writeTo(SecBuf + C->getRVA() - Sec->getRVA());
});
}
}