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Use DefinedSynthetic for _gp* symbols. 

The test changes to put _gp* in the .got section matches what both bfd
and gold do.

llvm-svn: 266067
This commit is contained in:
Rafael Espindola 2016-04-12 13:26:51 +00:00
parent 97f0dcdea8
commit 6f92e14ce2
10 changed files with 37 additions and 35 deletions
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12
lld/ELF/Symbols.h
View File

@ -403,10 +403,10 @@ template <class ELFT> struct ElfSym {
static DefinedRegular<ELFT> *End2;
// The content for _gp symbol for MIPS target.
static DefinedRegular<ELFT> *MipsGp;
static SymbolBody *MipsGp;
static DefinedRegular<ELFT> *MipsLocalGp;
static DefinedRegular<ELFT> *MipsGpDisp;
static SymbolBody *MipsLocalGp;
static SymbolBody *MipsGpDisp;
// __rel_iplt_start/__rel_iplt_end for signaling
// where R_[*]_IRELATIVE relocations do live.
@ -420,9 +420,9 @@ template <class ELFT> DefinedRegular<ELFT> *ElfSym<ELFT>::Edata;
template <class ELFT> DefinedRegular<ELFT> *ElfSym<ELFT>::Edata2;
template <class ELFT> DefinedRegular<ELFT> *ElfSym<ELFT>::End;
template <class ELFT> DefinedRegular<ELFT> *ElfSym<ELFT>::End2;
template <class ELFT> DefinedRegular<ELFT> *ElfSym<ELFT>::MipsGp;
template <class ELFT> DefinedRegular<ELFT> *ElfSym<ELFT>::MipsLocalGp;
template <class ELFT> DefinedRegular<ELFT> *ElfSym<ELFT>::MipsGpDisp;
template <class ELFT> SymbolBody *ElfSym<ELFT>::MipsGp;
template <class ELFT> SymbolBody *ElfSym<ELFT>::MipsLocalGp;
template <class ELFT> SymbolBody *ElfSym<ELFT>::MipsGpDisp;
template <class ELFT> SymbolBody *ElfSym<ELFT>::RelaIpltStart;
template <class ELFT> SymbolBody *ElfSym<ELFT>::RelaIpltEnd;

3
lld/ELF/Target.cpp
View File

@ -1920,8 +1920,7 @@ bool MipsTargetInfo<ELFT>::isRelRelative(uint32_t Type) const {
// a location that is relative to GOT. This function returns
// the value for the symbol.
template <class ELFT> typename ELFT::uint getMipsGpAddr() {
unsigned GPOffset = 0x7ff0;
return Out<ELFT>::Got->getVA() + GPOffset;
return Out<ELFT>::Got->getVA() + MipsGPOffset;
}
template uint32_t getMipsGpAddr<ELF32LE>();

1
lld/ELF/Target.h
View File

@ -119,6 +119,7 @@ private:
uint64_t getPPC64TocBase();
const unsigned MipsGPOffset = 0x7ff0;
template <class ELFT> typename ELFT::uint getMipsGpAddr();
extern TargetInfo *Target;

40
lld/ELF/Writer.cpp
View File

@ -795,6 +795,16 @@ bool Writer<ELFT>::isDiscarded(InputSectionBase<ELFT> *S) const {
Script->isDiscarded(S);
}
template <class ELFT>
static SymbolBody *
addOptionalSynthetic(SymbolTable<ELFT> &Table, StringRef Name,
OutputSectionBase<ELFT> &Sec, typename ELFT::uint Val,
uint8_t Visibility) {
if (!Table.find(Name))
return nullptr;
return Table.addSynthetic(Name, Sec, Val, Visibility);
}
// The beginning and the ending of .rel[a].plt section are marked
// with __rel[a]_iplt_{start,end} symbols if it is a statically linked
// executable. The runtime needs these symbols in order to resolve
@ -806,14 +816,13 @@ void Writer<ELFT>::addRelIpltSymbols() {
if (isOutputDynamic() || !Out<ELFT>::RelaPlt)
return;
StringRef S = Config->Rela ? "__rela_iplt_start" : "__rel_iplt_start";
if (Symtab.find(S))
ElfSym<ELFT>::RelaIpltStart =
Symtab.addSynthetic(S, *Out<ELFT>::RelaPlt, 0, STV_HIDDEN);
ElfSym<ELFT>::RelaIpltStart =
addOptionalSynthetic(Symtab, S, *Out<ELFT>::RelaPlt, 0, STV_HIDDEN);
S = Config->Rela ? "__rela_iplt_end" : "__rel_iplt_end";
if (Symtab.find(S))
ElfSym<ELFT>::RelaIpltEnd = Symtab.addSynthetic(
S, *Out<ELFT>::RelaPlt, DefinedSynthetic<ELFT>::SectionEnd, STV_HIDDEN);
ElfSym<ELFT>::RelaIpltEnd =
addOptionalSynthetic(Symtab, S, *Out<ELFT>::RelaPlt,
DefinedSynthetic<ELFT>::SectionEnd, STV_HIDDEN);
}
template <class ELFT> static bool includeInSymtab(const SymbolBody &B) {
@ -932,16 +941,19 @@ template <class ELFT> void Writer<ELFT>::addReservedSymbols() {
// so that it points to an absolute address which is relative to GOT.
// See "Global Data Symbols" in Chapter 6 in the following document:
// ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
ElfSym<ELFT>::MipsGp = Symtab.addAbsolute("_gp", STV_DEFAULT);
ElfSym<ELFT>::MipsGp =
Symtab.addSynthetic("_gp", *Out<ELFT>::Got, MipsGPOffset, STV_DEFAULT);
// On MIPS O32 ABI, _gp_disp is a magic symbol designates offset between
// start of function and 'gp' pointer into GOT.
ElfSym<ELFT>::MipsGpDisp = Symtab.addIgnored("_gp_disp");
ElfSym<ELFT>::MipsGpDisp = addOptionalSynthetic(
Symtab, "_gp_disp", *Out<ELFT>::Got, MipsGPOffset, STV_HIDDEN);
// The __gnu_local_gp is a magic symbol equal to the current value of 'gp'
// pointer. This symbol is used in the code generated by .cpload pseudo-op
// in case of using -mno-shared option.
// https://sourceware.org/ml/binutils/2004-12/msg00094.html
ElfSym<ELFT>::MipsLocalGp = Symtab.addIgnored("__gnu_local_gp");
ElfSym<ELFT>::MipsLocalGp = addOptionalSynthetic(
Symtab, "__gnu_local_gp", *Out<ELFT>::Got, MipsGPOffset, STV_HIDDEN);
}
// In the assembly for 32 bit x86 the _GLOBAL_OFFSET_TABLE_ symbol
@ -1515,16 +1527,6 @@ static uint16_t getELFType() {
// to each section. This function fixes some predefined absolute
// symbol values that depend on section address and size.
template <class ELFT> void Writer<ELFT>::fixAbsoluteSymbols() {
// Update MIPS _gp absolute symbol so that it points to the static data.
if (Config->EMachine == EM_MIPS) {
ElfSym<ELFT>::MipsGp->Value = getMipsGpAddr<ELFT>();
if (ElfSym<ELFT>::MipsLocalGp)
ElfSym<ELFT>::MipsLocalGp->Value = getMipsGpAddr<ELFT>();
if (ElfSym<ELFT>::MipsGpDisp)
ElfSym<ELFT>::MipsGpDisp->Value = getMipsGpAddr<ELFT>();
}
// _etext is the first location after the last read-only loadable segment.
// _edata is the first location after the last read-write loadable segment.
// _end is the first location after the uninitialized data region.

2
lld/test/ELF/basic-mips.s
View File

@ -219,7 +219,7 @@ __start:
# CHECK-NEXT: Binding: Global
# CHECK-NEXT: Type: None (0x0)
# CHECK-NEXT: Other: 0
# CHECK-NEXT: Section: Absolute (0xFFF1)
# CHECK-NEXT: Section: .got
# CHECK-NEXT: }
# CHECK-NEXT: ]
# CHECK-NEXT: ProgramHeaders [

4
lld/test/ELF/mips-got-relocs.s
View File

@ -48,7 +48,7 @@ v1:
# EXE_SYM: .got 0000000c 0000000000030000 DATA
# EXE_SYM: SYMBOL TABLE:
# EXE_SYM: 00040000 g .data 00000004 v1
# EXE_SYM: 00037ff0 *ABS* 00000000 _gp
# EXE_SYM: 00037ff0 .got 00000000 _gp
# ^-- .got + GP offset (0x7ff0)
@ -72,7 +72,7 @@ v1:
# DSO_SYM: .got 0000000c 0000000000020000 DATA
# DSO_SYM: SYMBOL TABLE:
# DSO_SYM: 00030000 g .data 00000004 v1
# DSO_SYM: 00027ff0 *ABS* 00000000 _gp
# DSO_SYM: 00027ff0 .got 00000000 _gp
# ^-- .got + GP offset (0x7ff0)
# DSO_GOT_BE: Contents of section .got:

2
lld/test/ELF/mips-gp-disp.s
View File

@ -24,7 +24,7 @@
# DIS-NEXT: 10000: 3c 08 00 01 lui $8, 1
# DIS-NEXT: 10004: 21 08 7f f0 addi $8, $8, 32752
# ^-- 0x37ff0 & 0xffff
# DIS: 00027ff0 *ABS* 00000000 _gp
# DIS: 00027ff0 .got 00000000 _gp
# REL: Relocations [
# REL-NEXT: ]

2
lld/test/ELF/mips-gp-local.s
View File

@ -11,7 +11,7 @@
# CHECK-NEXT: 20000: 3c 08 00 03 lui $8, 3
# CHECK-NEXT: 20004: 21 08 7f f0 addi $8, $8, 32752
# CHECK: 00037ff0 *ABS* 00000000 _gp
# CHECK: 00037ff0 .got 00000000 _gp
.text
.globl __start

2
lld/test/ELF/mips-gprel32-relocs.s
View File

@ -28,4 +28,4 @@ v1:
# CHECK: SYMBOL TABLE:
# CHECK: 00010008 .text 00000000 bar
# CHECK: 00010004 .text 00000000 foo
# CHECK: 00027ff0 *ABS* 00000000 _gp
# CHECK: 00027ff0 .got 00000000 _gp

4
lld/test/ELF/mips-hilo-gp-disp.s
View File

@ -27,7 +27,7 @@ __start:
# EXE: SYMBOL TABLE:
# EXE: 00020000 .text 00000000 __start
# EXE: 00020010 .text 00000000 _foo
# EXE: 00037ff0 *ABS* 00000000 _gp
# EXE: 00037ff0 .got 00000000 _gp
# SO: Disassembly of section .text:
# SO-NEXT: __start:
@ -39,4 +39,4 @@ __start:
# SO: SYMBOL TABLE:
# SO: 00010000 .text 00000000 __start
# SO: 00010010 .text 00000000 _foo
# SO: 00027ff0 *ABS* 00000000 _gp
# SO: 00027ff0 .got 00000000 _gp