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Drop vestigial support for UseLazyBinding=false. 

Lazy binding is quite important for use case like a shared build of
llvm. Also, if someone wants to disable it, it is better done in the
compiler (disable plt generation).

The only reason to keep it is to make it easier to add a new
architecture. But it doesn't really help much as it is possible to start
with non lazy relocation and plt code but still let the generic part
create a dedicated .got.plt and .rela.plt.

llvm-svn: 269982
This commit is contained in:
Rafael Espindola 2016-05-18 21:03:36 +00:00
parent 522afdd77e
commit e4c86d83fe
5 changed files with 17 additions and 37 deletions
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17
lld/ELF/OutputSections.cpp
View File

@ -270,17 +270,14 @@ PltSection<ELFT>::PltSection()
template <class ELFT> void PltSection<ELFT>::writeTo(uint8_t *Buf) {
size_t Off = 0;
if (Target->UseLazyBinding) {
// At beginning of PLT, we have code to call the dynamic linker
// to resolve dynsyms at runtime. Write such code.
Target->writePltZero(Buf);
Off += Target->PltZeroSize;
}
// At beginning of PLT, we have code to call the dynamic linker
// to resolve dynsyms at runtime. Write such code.
Target->writePltZero(Buf);
Off += Target->PltZeroSize;
for (auto &I : Entries) {
const SymbolBody *B = I.first;
unsigned RelOff = I.second;
uint64_t Got =
Target->UseLazyBinding ? B->getGotPltVA<ELFT>() : B->getGotVA<ELFT>();
uint64_t Got = B->getGotPltVA<ELFT>();
uint64_t Plt = this->getVA() + Off;
Target->writePlt(Buf + Off, Got, Plt, B->PltIndex, RelOff);
Off += Target->PltEntrySize;
@ -289,9 +286,7 @@ template <class ELFT> void PltSection<ELFT>::writeTo(uint8_t *Buf) {
template <class ELFT> void PltSection<ELFT>::addEntry(SymbolBody &Sym) {
Sym.PltIndex = Entries.size();
unsigned RelOff = Target->UseLazyBinding
? Out<ELFT>::RelaPlt->getRelocOffset()
: Out<ELFT>::RelaDyn->getRelocOffset();
unsigned RelOff = Out<ELFT>::RelaPlt->getRelocOffset();
Entries.push_back(std::make_pair(&Sym, RelOff));
}

6
lld/ELF/Target.cpp
View File

@ -264,7 +264,6 @@ X86TargetInfo::X86TargetInfo() {
TlsGotRel = R_386_TLS_TPOFF;
TlsModuleIndexRel = R_386_TLS_DTPMOD32;
TlsOffsetRel = R_386_TLS_DTPOFF32;
UseLazyBinding = true;
PltEntrySize = 16;
PltZeroSize = 16;
TlsGdToLeSkip = 2;
@ -495,7 +494,6 @@ X86_64TargetInfo::X86_64TargetInfo() {
TlsGotRel = R_X86_64_TPOFF64;
TlsModuleIndexRel = R_X86_64_DTPMOD64;
TlsOffsetRel = R_X86_64_DTPOFF64;
UseLazyBinding = true;
PltEntrySize = 16;
PltZeroSize = 16;
TlsGdToLeSkip = 2;
@ -760,7 +758,7 @@ RelExpr PPCTargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S) const {
}
PPC64TargetInfo::PPC64TargetInfo() {
GotRel = R_PPC64_GLOB_DAT;
PltRel = GotRel = R_PPC64_GLOB_DAT;
RelativeRel = R_PPC64_RELATIVE;
PltEntrySize = 32;
@ -936,7 +934,6 @@ AArch64TargetInfo::AArch64TargetInfo() {
TlsGotRel = R_AARCH64_TLS_TPREL64;
TlsModuleIndexRel = R_AARCH64_TLS_DTPMOD64;
TlsOffsetRel = R_AARCH64_TLS_DTPREL64;
UseLazyBinding = true;
PltEntrySize = 16;
PltZeroSize = 32;
}
@ -1235,7 +1232,6 @@ template <class ELFT> MipsTargetInfo<ELFT>::MipsTargetInfo() {
PltEntrySize = 16;
PltZeroSize = 32;
ThunkSize = 16;
UseLazyBinding = true;
CopyRel = R_MIPS_COPY;
PltRel = R_MIPS_JUMP_SLOT;
if (ELFT::Is64Bits)

1
lld/ELF/Target.h
View File

@ -84,7 +84,6 @@ public:
unsigned GotPltHeaderEntriesNum = 3;
uint32_t ThunkSize = 0;
bool UseLazyBinding = false;
virtual void relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, uint64_t Val) const;
virtual void relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const;

26
lld/ELF/Writer.cpp
View File

@ -170,11 +170,9 @@ template <class ELFT> void elf::writeResult(SymbolTable<ELFT> *Symtab) {
GnuHashTab.reset(new GnuHashTableSection<ELFT>);
if (Config->SysvHash)
HashTab.reset(new HashTableSection<ELFT>);
if (Target->UseLazyBinding) {
StringRef S = Config->Rela ? ".rela.plt" : ".rel.plt";
GotPlt.reset(new GotPltSection<ELFT>);
RelaPlt.reset(new RelocationSection<ELFT>(S, false /*Sort*/));
}
StringRef S = Config->Rela ? ".rela.plt" : ".rel.plt";
GotPlt.reset(new GotPltSection<ELFT>);
RelaPlt.reset(new RelocationSection<ELFT>(S, false /*Sort*/));
if (!Config->StripAll) {
StrTab.reset(new StringTableSection<ELFT>(".strtab", false));
SymTabSec.reset(new SymbolTableSection<ELFT>(*Symtab, *StrTab));
@ -733,20 +731,12 @@ void Writer<ELFT>::scanRelocs(InputSectionBase<ELFT> &C, ArrayRef<RelTy> Rels) {
if (Body.isGnuIFunc())
Rel = Preemptible ? Target->PltRel : Target->IRelativeRel;
else
Rel = Target->UseLazyBinding ? Target->PltRel : Target->GotRel;
Rel = Target->PltRel;
if (Target->UseLazyBinding) {
Out<ELFT>::GotPlt->addEntry(Body);
Out<ELFT>::RelaPlt->addReloc({Rel, Out<ELFT>::GotPlt,
Body.getGotPltOffset<ELFT>(),
!Preemptible, &Body, 0});
} else {
if (Body.isInGot())
continue;
Out<ELFT>::Got->addEntry(Body);
AddDyn({Rel, Out<ELFT>::Got, Body.getGotOffset<ELFT>(), !Preemptible,
&Body, 0});
}
Out<ELFT>::GotPlt->addEntry(Body);
Out<ELFT>::RelaPlt->addReloc({Rel, Out<ELFT>::GotPlt,
Body.getGotPltOffset<ELFT>(), !Preemptible,
&Body, 0});
continue;
}

4
lld/test/ELF/ppc64-toc-restore.s
View File

@ -53,8 +53,8 @@ last:
// CHECK: Disassembly of section .plt:
// CHECK: .plt:
// CHECK: 10010020: f8 41 00 28 std 2, 40(1)
// CHECK: 10010024: 3d 62 00 00 addis 11, 2, 0
// CHECK: 10010028: e9 8b 80 00 ld 12, -32768(11)
// CHECK: 10010024: 3d 62 10 03 addis 11, 2, 4099
// CHECK: 10010028: e9 8b 80 18 ld 12, -32744(11)
// CHECK: 1001002c: e9 6c 00 00 ld 11, 0(12)
// CHECK: 10010030: 7d 69 03 a6 mtctr 11
// CHECK: 10010034: e8 4c 00 08 ld 2, 8(12)