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Remove an unnecessary hack. 

It doesn't look like anything is depending on using local dynamic tls
relocations with preemptable  symbols.

llvm-svn: 262957
This commit is contained in:
Rafael Espindola 2016-03-08 21:17:31 +00:00
parent b8d071bc8a
commit e02f4dfb9e
7 changed files with 31 additions and 30 deletions
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2
lld/ELF/InputSection.cpp
View File

@ -271,7 +271,7 @@ void InputSectionBase<ELFT>::relocate(uint8_t *Buf, uint8_t *BufEnd,
}
uintX_t SymVA = Body->getVA<ELFT>();
bool CBP = canBePreempted(Body, Type);
bool CBP = canBePreempted(Body);
if (Target->needsPlt<ELFT>(Type, *Body)) {
SymVA = Body->getPltVA<ELFT>();
} else if (Target->needsGot(Type, *Body)) {

11
lld/ELF/OutputSections.cpp
View File

@ -176,7 +176,7 @@ template <class ELFT> void GotSection<ELFT>::writeTo(uint8_t *Buf) {
// for detailed description:
// ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
// As the first approach, we can just store addresses for all symbols.
if (Config->EMachine != EM_MIPS && canBePreempted(B, 0))
if (Config->EMachine != EM_MIPS && canBePreempted(B))
continue; // The dynamic linker will take care of it.
uintX_t VA = B->getVA<ELFT>();
write<uintX_t, ELFT::TargetEndianness, sizeof(uintX_t)>(Entry, VA);
@ -932,16 +932,9 @@ elf::getLocalRelTarget(const ObjectFile<ELFT> &File,
// Returns true if a symbol can be replaced at load-time by a symbol
// with the same name defined in other ELF executable or DSO.
bool elf::canBePreempted(const SymbolBody *Body, unsigned Type) {
bool elf::canBePreempted(const SymbolBody *Body) {
if (!Body)
return false; // Body is a local symbol.
// FIXME: Both gold and bfd consider that a local dynamic tls relocation to
// a symbol will not be preempted. Is that actually relevant? The compiler
// should not use it if the symbol can be preempted.
if (Target->isTlsLocalDynamicRel(Type))
return false;
if (Body->isShared())
return true;

2
lld/ELF/OutputSections.h
View File

@ -53,7 +53,7 @@ getLocalRelTarget(const ObjectFile<ELFT> &File,
const llvm::object::Elf_Rel_Impl<ELFT, IsRela> &Rel,
typename llvm::object::ELFFile<ELFT>::uintX_t Addend);
bool canBePreempted(const SymbolBody *Body, unsigned Type);
bool canBePreempted(const SymbolBody *Body);
bool isValidCIdentifier(StringRef S);

14
lld/ELF/Target.cpp
View File

@ -278,7 +278,7 @@ bool TargetInfo::canRelaxTls(uint32_t Type, const SymbolBody *S) const {
// Initial-Exec relocs can be relaxed to Local-Exec if the symbol is locally
// defined.
if (isTlsInitialExecRel(Type))
return !canBePreempted(S, Type);
return !canBePreempted(S);
return false;
}
@ -317,7 +317,7 @@ TargetInfo::PltNeed TargetInfo::needsPlt(uint32_t Type,
const SymbolBody &S) const {
if (isGnuIFunc<ELFT>(S))
return Plt_Explicit;
if (canBePreempted(&S, Type) && needsPltImpl(Type))
if (canBePreempted(&S) && needsPltImpl(Type))
return Plt_Explicit;
// This handles a non PIC program call to function in a shared library.
@ -470,7 +470,7 @@ bool X86TargetInfo::needsCopyRelImpl(uint32_t Type) const {
bool X86TargetInfo::needsGot(uint32_t Type, SymbolBody &S) const {
if (S.IsTls && Type == R_386_TLS_GD)
return Target->canRelaxTls(Type, &S) && canBePreempted(&S, Type);
return Target->canRelaxTls(Type, &S) && canBePreempted(&S);
if (Type == R_386_TLS_GOTIE || Type == R_386_TLS_IE)
return !canRelaxTls(Type, &S);
return Type == R_386_GOT32 || needsPlt<ELF32LE>(Type, S);
@ -548,7 +548,7 @@ size_t X86TargetInfo::relaxTls(uint8_t *Loc, uint8_t *BufEnd, uint32_t Type,
const SymbolBody *S) const {
switch (Type) {
case R_386_TLS_GD:
if (canBePreempted(S, Type))
if (canBePreempted(S))
relocateTlsGdToIe(Loc, BufEnd, P, SA);
else
relocateTlsGdToLe(Loc, BufEnd, P, SA);
@ -732,7 +732,7 @@ bool X86_64TargetInfo::refersToGotEntry(uint32_t Type) const {
bool X86_64TargetInfo::needsGot(uint32_t Type, SymbolBody &S) const {
if (Type == R_X86_64_TLSGD)
return Target->canRelaxTls(Type, &S) && canBePreempted(&S, Type);
return Target->canRelaxTls(Type, &S) && canBePreempted(&S);
if (Type == R_X86_64_GOTTPOFF)
return !canRelaxTls(Type, &S);
return refersToGotEntry(Type) || needsPlt<ELF64LE>(Type, S);
@ -899,7 +899,7 @@ size_t X86_64TargetInfo::relaxTls(uint8_t *Loc, uint8_t *BufEnd, uint32_t Type,
relocateTlsIeToLe(Loc, BufEnd, P, SA);
return 0;
case R_X86_64_TLSGD: {
if (canBePreempted(S, Type))
if (canBePreempted(S))
relocateTlsGdToIe(Loc, BufEnd, P, SA);
else
relocateTlsGdToLe(Loc, BufEnd, P, SA);
@ -1466,7 +1466,7 @@ size_t AArch64TargetInfo::relaxTls(uint8_t *Loc, uint8_t *BufEnd, uint32_t Type,
case R_AARCH64_TLSDESC_LD64_LO12_NC:
case R_AARCH64_TLSDESC_ADD_LO12_NC:
case R_AARCH64_TLSDESC_CALL: {
if (canBePreempted(S, Type))
if (canBePreempted(S))
fatal("Unsupported TLS optimization");
uint64_t X = S ? S->getVA<ELF64LE>() : SA;
relocateTlsGdToLe(Type, Loc, BufEnd, P, X);

4
lld/ELF/Writer.cpp
View File

@ -281,7 +281,7 @@ static bool handleTlsRelocation(uint32_t Type, SymbolBody *Body,
}
return true;
}
if (!canBePreempted(Body, Type))
if (!canBePreempted(Body))
return true;
}
return false;
@ -327,7 +327,7 @@ void Writer<ELFT>::scanRelocs(
if (Body)
Body = Body->repl();
bool CBP = canBePreempted(Body, Type);
bool CBP = canBePreempted(Body);
if (handleTlsRelocation<ELFT>(Type, Body, C, RI))
continue;

20
lld/test/ELF/tls-dynamic-i686.s
View File

@ -19,6 +19,14 @@ tls1:
.long 0
.size tls1, 4
.type tls2,@object
.globl tls2
.hidden tls2
.align 4
tls2:
.long 0
.size tls2, 4
.section .text
.globl _start
_start:
@ -28,13 +36,13 @@ call __tls_get_addr@plt
leal tls1@tlsgd(,%ebx,1),%eax
call __tls_get_addr@plt
leal tls0@tlsldm(%ebx),%eax
leal tls2@tlsldm(%ebx),%eax
call __tls_get_addr@plt
leal tls0@dtpoff(%eax),%edx
leal tls2@dtpoff(%eax),%edx
leal tls1@tlsldm(%ebx),%eax
leal tls2@tlsldm(%ebx),%eax
call __tls_get_addr@plt
leal tls1@dtpoff(%eax),%edx
leal tls2@dtpoff(%eax),%edx
movl %gs:0,%eax
addl tls0@gotntpoff(%ebx),%eax
@ -81,10 +89,10 @@ addl tls1@gotntpoff(%ebx),%eax
// -16 is a local module tls index offset.
// DIS-NEXT: 1018: 8d 83 f0 ff ff ff leal -16(%ebx), %eax
// DIS-NEXT: 101e: e8 4d 00 00 00 calll 77
// DIS-NEXT: 1023: 8d 90 00 00 00 00 leal (%eax), %edx
// DIS-NEXT: 1023: 8d 90 08 00 00 00 leal 8(%eax), %edx
// DIS-NEXT: 1029: 8d 83 f0 ff ff ff leal -16(%ebx), %eax
// DIS-NEXT: 102f: e8 3c 00 00 00 calll 60
// DIS-NEXT: 1034: 8d 90 04 00 00 00 leal 4(%eax), %edx
// DIS-NEXT: 1034: 8d 90 08 00 00 00 leal 8(%eax), %edx
// Initial exec model:
// DIS-NEXT: 103a: 65 a1 00 00 00 00 movl %gs:0, %eax
// DIS-NEXT: 1040: 03 83 f8 ff ff ff addl -8(%ebx), %eax

8
lld/test/ELF/tls-dynamic.s
View File

@ -14,13 +14,13 @@
leaq c@tlsgd(%rip), %rdi
rex64
callq __tls_get_addr@PLT
leaq c@dtpoff(%rax), %rcx
leaq a@dtpoff(%rax), %rcx
// Initial Exec Model Code Sequence, II
movq c@gottpoff(%rip),%rax
movq %fs:(%rax),%rax
movabs $a@dtpoff, %rax
movabs $b@dtpoff, %rax
movabs $c@dtpoff, %rax
movabs $a@dtpoff, %rax
.global a
.hidden a
@ -79,9 +79,9 @@ c:
// DIS-NEXT: 102c: 00 00
// DIS-NEXT: 102e: {{.+}} leaq 4267(%rip), %rdi
// DIS-NEXT: 1035: {{.+}} callq
// DIS-NEXT: 103b: {{.+}} leaq 8(%rax), %rcx
// DIS-NEXT: 103b: {{.+}} leaq (%rax), %rcx
// DIS-NEXT: 1042: {{.+}} movq 4263(%rip), %rax
// DIS-NEXT: 1049: {{.+}} movq %fs:(%rax), %rax
// DIS-NEXT: 104d: {{.+}} movabsq $0, %rax
// DIS-NEXT: 1057: {{.+}} movabsq $4, %rax
// DIS-NEXT: 1061: {{.+}} movabsq $8, %rax
// DIS-NEXT: 1061: {{.+}} movabsq $0, %rax