Index: ELF/SyntheticSections.cpp =================================================================== --- ELF/SyntheticSections.cpp +++ ELF/SyntheticSections.cpp @@ -728,11 +728,7 @@ template void IgotPltSection::writeTo(uint8_t *Buf) { for (const SymbolBody *B : Entries) { - if (Config->EMachine == EM_ARM) - // On ARM we are actually part of the Got and not GotPlt. - write32le(Buf, B->getVA()); - else - Target->writeGotPlt(Buf, *B); + Target->writeIgotPlt(Buf, *B); Buf += sizeof(uintX_t); } } Index: ELF/Target.h =================================================================== --- ELF/Target.h +++ ELF/Target.h @@ -30,6 +30,7 @@ virtual uint32_t getDynRel(uint32_t Type) const { return Type; } virtual void writeGotPltHeader(uint8_t *Buf) const {} virtual void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const {}; + virtual void writeIgotPlt(uint8_t *Buf, const SymbolBody &S) const; virtual uint64_t getImplicitAddend(const uint8_t *Buf, uint32_t Type) const; // If lazy binding is supported, the first entry of the PLT has code Index: ELF/Target.cpp =================================================================== --- ELF/Target.cpp +++ ELF/Target.cpp @@ -95,6 +95,7 @@ bool isTlsGlobalDynamicRel(uint32_t Type) const override; bool isTlsInitialExecRel(uint32_t Type) const override; void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const override; + void writeIgotPlt(uint8_t *Buf, const SymbolBody &S) const override; void writePltHeader(uint8_t *Buf) const override; void writePlt(uint8_t *Buf, uint64_t GotEntryAddr, uint64_t PltEntryAddr, int32_t Index, unsigned RelOff) const override; @@ -189,6 +190,7 @@ bool isTlsGlobalDynamicRel(uint32_t Type) const override; bool isTlsInitialExecRel(uint32_t Type) const override; void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const override; + void writeIgotPlt(uint8_t *Buf, const SymbolBody &S) const override; void writePltHeader(uint8_t *Buf) const override; void writePlt(uint8_t *Buf, uint64_t GotEntryAddr, uint64_t PltEntryAddr, int32_t Index, unsigned RelOff) const override; @@ -274,6 +276,10 @@ bool TargetInfo::isTlsGlobalDynamicRel(uint32_t Type) const { return false; } +void TargetInfo::writeIgotPlt(uint8_t *Buf, const SymbolBody &S) const { + writeGotPlt(Buf, S); +} + RelExpr TargetInfo::adjustRelaxExpr(uint32_t Type, const uint8_t *Data, RelExpr Expr) const { return Expr; @@ -371,6 +377,11 @@ write32le(Buf, S.getPltVA() + 6); } +void X86TargetInfo::writeIgotPlt(uint8_t *Buf, const SymbolBody &S) const { + // An x86 entry is the address of the ifunc resolver function. + write32le(Buf, S.getVA()); +} + uint32_t X86TargetInfo::getDynRel(uint32_t Type) const { if (Type == R_386_TLS_LE) return R_386_TLS_TPOFF; @@ -1649,6 +1660,11 @@ write32le(Buf, In::Plt->getVA()); } +void ARMTargetInfo::writeIgotPlt(uint8_t *Buf, const SymbolBody &S) const { + // An ARM entry is the address of the ifunc resolver function. + write32le(Buf, S.getVA()); +} + void ARMTargetInfo::writePltHeader(uint8_t *Buf) const { const uint8_t PltData[] = { 0x04, 0xe0, 0x2d, 0xe5, // str lr, [sp,#-4]! Index: test/ELF/gnu-ifunc-plt-i386.s =================================================================== --- /dev/null +++ test/ELF/gnu-ifunc-plt-i386.s @@ -0,0 +1,76 @@ +// RUN: llvm-mc -filetype=obj -triple=i686-pc-linux %S/Inputs/shared2-x86-64.s -o %t1.o +// RUN: ld.lld %t1.o --shared -o %t.so +// RUN: llvm-mc -filetype=obj -triple=i686-pc-linux %s -o %t.o +// RUN: ld.lld %t.so %t.o -o %tout +// RUN: llvm-objdump -d %tout | FileCheck %s --check-prefix=DISASM +// RUN: llvm-objdump -s %tout | FileCheck %s --check-prefix=GOTPLT +// RUN: llvm-readobj -r -dynamic-table %tout | FileCheck %s +// REQUIRES: x86 + +// Check that the IRELATIVE relocations are after the JUMP_SLOT in the plt +// CHECK: Relocations [ +// CHECK-NEXT: Section (4) .rel.plt { +// CHECK-NEXT: 0x1300C R_386_JUMP_SLOT bar2 +// CHECK-NEXT: 0x13010 R_386_JUMP_SLOT zed2 +// CHECK-NEXT: 0x13014 R_386_IRELATIVE +// CHECK-NEXT: 0x13018 R_386_IRELATIVE + +// Check that IRELATIVE .got.plt entries point to ifunc resolver and not +// back to the plt entry + 6. +// GOTPLT: Contents of section .got.plt: +// GOTPLT: 13000 00200100 00000000 00000000 36100100 +// GOTPLT-NEXT: 13010 46100100 00100100 01100100 + +// Check that the PLTRELSZ tag includes the IRELATIVE relocations +// CHECK: DynamicSection [ +// CHECK: 0x00000002 PLTRELSZ 32 (bytes) + +// Check that a PLT header is written and the ifunc entries appear last +// DISASM: Disassembly of section .text: +// DISASM-NEXT: foo: +// DISASM-NEXT: 11000: c3 retl +// DISASM: bar: +// DISASM-NEXT: 11001: c3 retl +// DISASM: _start: +// DISASM-NEXT: 11002: e8 49 00 00 00 calll 73 +// DISASM-NEXT: 11007: e8 54 00 00 00 calll 84 +// DISASM-NEXT: 1100c: e8 1f 00 00 00 calll 31 +// DISASM-NEXT: 11011: e8 2a 00 00 00 calll 42 +// DISASM-NEXT: Disassembly of section .plt: +// DISASM-NEXT: .plt: +// DISASM-NEXT: 11020: ff 35 04 30 01 00 pushl 77828 +// DISASM-NEXT: 11026: ff 25 08 30 01 00 jmpl *77832 +// DISASM-NEXT: 1102c: 90 nop +// DISASM-NEXT: 1102d: 90 nop +// DISASM-NEXT: 1102e: 90 nop +// DISASM-NEXT: 1102f: 90 nop +// DISASM-NEXT: 11030: ff 25 0c 30 01 00 jmpl *77836 +// DISASM-NEXT: 11036: 68 00 00 00 00 pushl $0 +// DISASM-NEXT: 1103b: e9 e0 ff ff ff jmp -32 <.plt> +// DISASM-NEXT: 11040: ff 25 10 30 01 00 jmpl *77840 +// DISASM-NEXT: 11046: 68 08 00 00 00 pushl $8 +// DISASM-NEXT: 1104b: e9 d0 ff ff ff jmp -48 <.plt> +// DISASM-NEXT: 11050: ff 25 14 30 01 00 jmpl *77844 +// DISASM-NEXT: 11056: 68 30 00 00 00 pushl $48 +// DISASM-NEXT: 1105b: e9 e0 ff ff ff jmp -32 <.plt+0x20> +// DISASM-NEXT: 11060: ff 25 18 30 01 00 jmpl *77848 +// DISASM-NEXT: 11066: 68 38 00 00 00 pushl $56 +// DISASM-NEXT: 1106b: e9 d0 ff ff ff jmp -48 <.plt+0x20> + +.text +.type foo STT_GNU_IFUNC +.globl foo +foo: + ret + +.type bar STT_GNU_IFUNC +.globl bar +bar: + ret + +.globl _start +_start: + call foo + call bar + call bar2 + call zed2