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Simplify. Thanks to Rui for the suggestion. 

llvm-svn: 270551
This commit is contained in:
Rafael Espindola 2016-05-24 11:53:15 +00:00
parent 97434957ef
commit dba64b8ea4
8 changed files with 184 additions and 12 deletions
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16
lld/ELF/InputSection.cpp
View File

@ -169,6 +169,7 @@ getSymVA(uint32_t Type, typename ELFT::uint A, typename ELFT::uint P,
switch (Expr) {
case R_HINT:
llvm_unreachable("cannot relocate hint relocs");
case R_RELAXABLE_GOT_PC:
case R_RELAX_TLS_GD_TO_LE:
case R_RELAX_TLS_GD_TO_IE:
case R_RELAX_TLS_IE_TO_LE:
@ -250,6 +251,7 @@ getSymVA(uint32_t Type, typename ELFT::uint A, typename ELFT::uint P,
return SymVA - P;
}
case R_PC:
case R_RELAX_GOT_PC:
return Body.getVA<ELFT>(A) - P;
case R_PAGE_PC:
return getAArch64Page(Body.getVA<ELFT>(A)) - getAArch64Page(P);
@ -317,13 +319,10 @@ void InputSectionBase<ELFT>::relocate(uint8_t *Buf, uint8_t *BufEnd) {
uint64_t SymVA = SignExtend64<Bits>(
getSymVA<ELFT>(Type, A, AddrLoc, *Rel.Sym, BufLoc, *File, Expr));
if (Expr == R_PPC_PLT_OPD) {
uint32_t Nop = 0x60000000;
if (BufLoc + 8 <= BufEnd && read32be(BufLoc + 4) == Nop)
write32be(BufLoc + 4, 0xe8410028); // ld %r2, 40(%r1)
}
switch (Expr) {
case R_RELAX_GOT_PC:
Target->relaxGot(BufLoc, SymVA);
break;
case R_RELAX_TLS_IE_TO_LE:
Target->relaxTlsIeToLe(BufLoc, Type, SymVA);
break;
@ -336,6 +335,11 @@ void InputSectionBase<ELFT>::relocate(uint8_t *Buf, uint8_t *BufEnd) {
case R_RELAX_TLS_GD_TO_IE:
Target->relaxTlsGdToIe(BufLoc, Type, SymVA);
break;
case R_PPC_PLT_OPD:
// Patch a nop (0x60000000) to a ld.
if (BufLoc + 8 <= BufEnd && read32be(BufLoc + 4) == 0x60000000)
write32be(BufLoc + 4, 0xe8410028); // ld %r2, 40(%r1)
// fallthrough
default:
Target->relocateOne(BufLoc, Type, SymVA);
break;

2
lld/ELF/InputSection.h
View File

@ -47,6 +47,8 @@ enum RelExpr {
R_PPC_OPD,
R_PPC_PLT_OPD,
R_PPC_TOC,
R_RELAXABLE_GOT_PC,
R_RELAX_GOT_PC,
R_RELAX_TLS_GD_TO_IE,
R_RELAX_TLS_GD_TO_LE,
R_RELAX_TLS_IE_TO_LE,

15
lld/ELF/Target.cpp
View File

@ -113,6 +113,7 @@ public:
int32_t Index, unsigned RelOff) const override;
void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
void relaxGot(uint8_t *Loc, uint64_t Val) const override;
void relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
void relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
void relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override;
@ -232,6 +233,10 @@ bool TargetInfo::isTlsGlobalDynamicRel(uint32_t Type) const {
return false;
}
void TargetInfo::relaxGot(uint8_t *Loc, uint64_t Val) const {
llvm_unreachable("Should not have claimed to be relaxable");
}
void TargetInfo::relaxTlsGdToLe(uint8_t *Loc, uint32_t Type,
uint64_t Val) const {
llvm_unreachable("Should not have claimed to be relaxable");
@ -516,10 +521,11 @@ RelExpr X86_64TargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S) const {
case R_X86_64_GOT32:
return R_GOT_FROM_END;
case R_X86_64_GOTPCREL:
case R_X86_64_GOTPCRELX:
case R_X86_64_REX_GOTPCRELX:
case R_X86_64_GOTTPOFF:
return R_GOT_PC;
case R_X86_64_GOTPCRELX:
case R_X86_64_REX_GOTPCRELX:
return R_RELAXABLE_GOT_PC;
}
}
@ -727,6 +733,11 @@ void X86_64TargetInfo::relocateOne(uint8_t *Loc, uint32_t Type,
}
}
void X86_64TargetInfo::relaxGot(uint8_t *Loc, uint64_t Val) const {
Loc[-2] = 0x8d;
relocateOne(Loc, R_X86_64_PC32, Val);
}
// Relocation masks following the #lo(value), #hi(value), #ha(value),
// #higher(value), #highera(value), #highest(value), and #highesta(value)
// macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi

1
lld/ELF/Target.h
View File

@ -88,6 +88,7 @@ public:
uint32_t ThunkSize = 0;
virtual void relaxGot(uint8_t *Loc, uint64_t Val) const;
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;
virtual void relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const;

16
lld/ELF/Writer.cpp
View File

@ -432,7 +432,8 @@ static bool needsPlt(RelExpr Expr) {
// True if this expression is of the form Sym - X, where X is a position in the
// file (PC, or GOT for example).
static bool isRelExpr(RelExpr Expr) {
return Expr == R_PC || Expr == R_GOTREL || Expr == R_PAGE_PC;
return Expr == R_PC || Expr == R_GOTREL || Expr == R_PAGE_PC ||
Expr == R_RELAX_GOT_PC;
}
template <class ELFT>
@ -510,10 +511,17 @@ static RelExpr adjustExpr(const elf::ObjectFile<ELFT> &File, SymbolBody &Body,
if (Target->needsThunk(Type, File, Body))
return R_THUNK;
bool Preemptible = Body.isPreemptible();
if (Body.isGnuIFunc())
if (Body.isGnuIFunc()) {
Expr = toPlt(Expr);
else if (needsPlt(Expr) && !Preemptible)
Expr = fromPlt(Expr);
} else if (!Preemptible) {
if (needsPlt(Expr))
Expr = fromPlt(Expr);
if (Expr == R_RELAXABLE_GOT_PC)
Expr = R_RELAX_GOT_PC;
}
if (Expr == R_RELAXABLE_GOT_PC)
Expr = R_GOT_PC;
if (IsWrite || isStaticLinkTimeConstant<ELFT>(Expr, Type, Body))
return Expr;

4
lld/test/ELF/Inputs/gotpc-relax-und-dso.s Normal file
View File

@ -0,0 +1,4 @@
.globl dsofoo
.type dsofoo, @function
dsofoo:
nop

73
lld/test/ELF/gotpc-relax-und-dso.s Normal file
View File

@ -0,0 +1,73 @@
# REQUIRES: x86
# RUN: llvm-mc -filetype=obj -relax-relocations -triple=x86_64-unknown-linux %s -o %t.o
# RUN: llvm-mc -filetype=obj -relax-relocations -triple=x86_64-pc-linux %S/Inputs/gotpc-relax-und-dso.s -o %tdso.o
# RUN: ld.lld -shared %tdso.o -o %t.so
# RUN: ld.lld -shared %t.o %t.so -o %tout
# RUN: llvm-readobj -r -s %tout | FileCheck --check-prefix=RELOC %s
# RUN: llvm-objdump -d %tout | FileCheck --check-prefix=DISASM %s
# RELOC: Relocations [
# RELOC-NEXT: Section ({{.*}}) .rela.dyn {
# RELOC-NEXT: 0x20A8 R_X86_64_GLOB_DAT dsofoo 0x0
# RELOC-NEXT: 0x20B0 R_X86_64_GLOB_DAT foo 0x0
# RELOC-NEXT: 0x20A0 R_X86_64_GLOB_DAT und 0x0
# RELOC-NEXT: }
# RELOC-NEXT: ]
# 0x101e + 7 - 36 = 0x1001
# 0x1025 + 7 - 43 = 0x1001
# DISASM: Disassembly of section .text:
# DISASM-NEXT: foo:
# DISASM-NEXT: 1000: 90 nop
# DISASM: hid:
# DISASM-NEXT: 1001: 90 nop
# DISASM: _start:
# DISASM-NEXT: 1002: 48 8b 05 97 10 00 00 movq 4247(%rip), %rax
# DISASM-NEXT: 1009: 48 8b 05 90 10 00 00 movq 4240(%rip), %rax
# DISASM-NEXT: 1010: 48 8b 05 91 10 00 00 movq 4241(%rip), %rax
# DISASM-NEXT: 1017: 48 8b 05 8a 10 00 00 movq 4234(%rip), %rax
# DISASM-NEXT: 101e: 48 8d 05 dc ff ff ff leaq -36(%rip), %rax
# DISASM-NEXT: 1025: 48 8d 05 d5 ff ff ff leaq -43(%rip), %rax
# DISASM-NEXT: 102c: 48 8b 05 7d 10 00 00 movq 4221(%rip), %rax
# DISASM-NEXT: 1033: 48 8b 05 76 10 00 00 movq 4214(%rip), %rax
# DISASM-NEXT: 103a: 8b 05 60 10 00 00 movl 4192(%rip), %eax
# DISASM-NEXT: 1040: 8b 05 5a 10 00 00 movl 4186(%rip), %eax
# DISASM-NEXT: 1046: 8b 05 5c 10 00 00 movl 4188(%rip), %eax
# DISASM-NEXT: 104c: 8b 05 56 10 00 00 movl 4182(%rip), %eax
# DISASM-NEXT: 1052: 8d 05 a9 ff ff ff leal -87(%rip), %eax
# DISASM-NEXT: 1058: 8d 05 a3 ff ff ff leal -93(%rip), %eax
# DISASM-NEXT: 105e: 8b 05 4c 10 00 00 movl 4172(%rip), %eax
# DISASM-NEXT: 1064: 8b 05 46 10 00 00 movl 4166(%rip), %eax
.text
.globl foo
.type foo, @function
foo:
nop
.globl hid
.hidden hid
.type hid, @function
hid:
nop
.globl _start
.type _start, @function
_start:
movq und@GOTPCREL(%rip), %rax
movq und@GOTPCREL(%rip), %rax
movq dsofoo@GOTPCREL(%rip), %rax
movq dsofoo@GOTPCREL(%rip), %rax
movq hid@GOTPCREL(%rip), %rax
movq hid@GOTPCREL(%rip), %rax
movq foo@GOTPCREL(%rip), %rax
movq foo@GOTPCREL(%rip), %rax
movl und@GOTPCREL(%rip), %eax
movl und@GOTPCREL(%rip), %eax
movl dsofoo@GOTPCREL(%rip), %eax
movl dsofoo@GOTPCREL(%rip), %eax
movl hid@GOTPCREL(%rip), %eax
movl hid@GOTPCREL(%rip), %eax
movl foo@GOTPCREL(%rip), %eax
movl foo@GOTPCREL(%rip), %eax

69
lld/test/ELF/gotpc-relax.s Normal file
View File

@ -0,0 +1,69 @@
# REQUIRES: x86
# RUN: llvm-mc -filetype=obj -relax-relocations -triple=x86_64-unknown-linux %s -o %t.o
# RUN: ld.lld %t.o -o %t1
# RUN: llvm-readobj -r %t1 | FileCheck --check-prefix=RELOC %s
# RUN: llvm-objdump -d %t1 | FileCheck --check-prefix=DISASM %s
## There is no relocations.
# RELOC: Relocations [
# RELOC: ]
# 0x11003 + 7 - 10 = 0x11000
# 0x1100a + 7 - 17 = 0x11000
# 0x11011 + 7 - 23 = 0x11001
# 0x11018 + 7 - 30 = 0x11001
# DISASM: Disassembly of section .text:
# DISASM-NEXT: foo:
# DISASM-NEXT: 11000: 90 nop
# DISASM: hid:
# DISASM-NEXT: 11001: 90 nop
# DISASM: ifunc:
# DISASM-NEXT: 11002: c3 retq
# DISASM: _start:
# DISASM-NEXT: 11003: 48 8d 05 f6 ff ff ff leaq -10(%rip), %rax
# DISASM-NEXT: 1100a: 48 8d 05 ef ff ff ff leaq -17(%rip), %rax
# DISASM-NEXT: 11011: 48 8d 05 e9 ff ff ff leaq -23(%rip), %rax
# DISASM-NEXT: 11018: 48 8d 05 e2 ff ff ff leaq -30(%rip), %rax
# DISASM-NEXT: 1101f: 48 8b 05 da 0f 00 00 movq 4058(%rip), %rax
# DISASM-NEXT: 11026: 48 8b 05 d3 0f 00 00 movq 4051(%rip), %rax
# DISASM-NEXT: 1102d: 8d 05 cd ff ff ff leal -51(%rip), %eax
# DISASM-NEXT: 11033: 8d 05 c7 ff ff ff leal -57(%rip), %eax
# DISASM-NEXT: 11039: 8d 05 c2 ff ff ff leal -62(%rip), %eax
# DISASM-NEXT: 1103f: 8d 05 bc ff ff ff leal -68(%rip), %eax
# DISASM-NEXT: 11045: 8b 05 b5 0f 00 00 movl 4021(%rip), %eax
# DISASM-NEXT: 1104b: 8b 05 af 0f 00 00 movl 4015(%rip), %eax
.text
.globl foo
.type foo, @function
foo:
nop
.globl hid
.hidden hid
.type hid, @function
hid:
nop
.text
.type ifunc STT_GNU_IFUNC
.globl ifunc
.type ifunc, @function
ifunc:
ret
.globl _start
.type _start, @function
_start:
movq foo@GOTPCREL(%rip), %rax
movq foo@GOTPCREL(%rip), %rax
movq hid@GOTPCREL(%rip), %rax
movq hid@GOTPCREL(%rip), %rax
movq ifunc@GOTPCREL(%rip), %rax
movq ifunc@GOTPCREL(%rip), %rax
movl foo@GOTPCREL(%rip), %eax
movl foo@GOTPCREL(%rip), %eax
movl hid@GOTPCREL(%rip), %eax
movl hid@GOTPCREL(%rip), %eax
movl ifunc@GOTPCREL(%rip), %eax
movl ifunc@GOTPCREL(%rip), %eax