[lld] r261651 - [lld] [ELF/AArch64] Fix R_AARCH64_ABS64 in Shared mode
Adhemerval Zanella via llvm-commits
llvm-commits at lists.llvm.org
Tue Feb 23 08:54:41 PST 2016
Author: azanella
Date: Tue Feb 23 10:54:40 2016
New Revision: 261651
URL: http://llvm.org/viewvc/llvm-project?rev=261651&view=rev
Log:
[lld] [ELF/AArch64] Fix R_AARCH64_ABS64 in Shared mode
This patch fixes the R_AARCH64_ABS64 relocation when used in shared mode,
where it requires a dynamic R_AARCH64_RELATIVE relocation. To correct set
the addend on the dynamic relocation (since it will be used by the dynamic
linker), a new TargetInfo specific hook was created (getDynRelativeAddend)
to get the correct addend based on relocation type.
The patch fixes the issues when creating shared library code against
{init,fini}_array, where it issues R_AARCH64_ABS64 relocation against
local symbols.
Added:
lld/trunk/test/ELF/aarch64-abs64-dyn.s
Modified:
lld/trunk/ELF/OutputSections.cpp
lld/trunk/ELF/OutputSections.h
lld/trunk/ELF/Target.cpp
lld/trunk/ELF/Writer.cpp
Modified: lld/trunk/ELF/OutputSections.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/OutputSections.cpp?rev=261651&r1=261650&r2=261651&view=diff
==============================================================================
--- lld/trunk/ELF/OutputSections.cpp (original)
+++ lld/trunk/ELF/OutputSections.cpp Tue Feb 23 10:54:40 2016
@@ -253,11 +253,18 @@ template <class ELFT> void RelocationSec
if (IsRela) {
uintX_t VA = 0;
- if (Rel.UseSymVA)
+ if (Rel.UseSymVA) {
VA = Sym->getVA<ELFT>();
- else if (Rel.TargetSec)
+ } else if (Rel.TargetSec) {
VA = Rel.TargetSec->getOffset(Rel.OffsetInTargetSec) +
Rel.TargetSec->OutSec->getVA();
+ } else if (!Sym && Rel.OffsetSec) {
+ // Sym equal to nullptr means the dynamic relocation is against a
+ // local symbol represented by Rel.SymIndex.
+ ObjectFile<ELFT> *File = Rel.OffsetSec->getFile();
+ const Elf_Sym *LocalSym = File->getLocalSymbol(Rel.SymIndex);
+ VA = getLocalTarget(*File, *LocalSym, 0);
+ }
reinterpret_cast<Elf_Rela *>(P)->r_addend = Rel.Addend + VA;
}
@@ -862,7 +869,6 @@ elf2::getLocalRelTarget(const ObjectFile
const Elf_Rel_Impl<ELFT, IsRela> &RI,
typename ELFFile<ELFT>::uintX_t Addend) {
typedef typename ELFFile<ELFT>::Elf_Sym Elf_Sym;
- typedef typename ELFFile<ELFT>::uintX_t uintX_t;
// PPC64 has a special relocation representing the TOC base pointer
// that does not have a corresponding symbol.
@@ -875,10 +881,22 @@ elf2::getLocalRelTarget(const ObjectFile
if (!Sym)
fatal("Unsupported relocation without symbol");
- InputSectionBase<ELFT> *Section = File.getSection(*Sym);
+ return getLocalTarget(File, *Sym, Addend);
+}
+
+template <class ELFT>
+typename ELFFile<ELFT>::uintX_t
+elf2::getLocalTarget(const ObjectFile<ELFT> &File,
+ const typename ELFFile<ELFT>::Elf_Sym &Sym,
+ typename ELFFile<ELFT>::uintX_t Addend) {
+ typedef typename ELFFile<ELFT>::uintX_t uintX_t;
+
+ InputSectionBase<ELFT> *Section = File.getSection(Sym);
+ if (!Section)
+ return Addend;
- if (Sym->getType() == STT_TLS)
- return (Section->OutSec->getVA() + Section->getOffset(*Sym) + Addend) -
+ if (Sym.getType() == STT_TLS)
+ return (Section->OutSec->getVA() + Section->getOffset(Sym) + Addend) -
Out<ELFT>::TlsPhdr->p_vaddr;
// According to the ELF spec reference to a local symbol from outside
@@ -888,8 +906,8 @@ elf2::getLocalRelTarget(const ObjectFile
if (Section == &InputSection<ELFT>::Discarded || !Section->isLive())
return Addend;
- uintX_t Offset = Sym->st_value;
- if (Sym->getType() == STT_SECTION) {
+ uintX_t Offset = Sym.st_value;
+ if (Sym.getType() == STT_SECTION) {
Offset += Addend;
Addend = 0;
}
@@ -1647,5 +1665,18 @@ template uint64_t getLocalRelTarget(cons
template uint64_t getLocalRelTarget(const ObjectFile<ELF64BE> &,
const ELFFile<ELF64BE>::Elf_Rela &,
uint64_t);
+
+template uint32_t getLocalTarget(const ObjectFile<ELF32LE> &,
+ const ELFFile<ELF32LE>::Elf_Sym &Sym,
+ uint32_t);
+template uint32_t getLocalTarget(const ObjectFile<ELF32BE> &,
+ const ELFFile<ELF32BE>::Elf_Sym &Sym,
+ uint32_t);
+template uint64_t getLocalTarget(const ObjectFile<ELF64LE> &,
+ const ELFFile<ELF64LE>::Elf_Sym &Sym,
+ uint64_t);
+template uint64_t getLocalTarget(const ObjectFile<ELF64BE> &,
+ const ELFFile<ELF64BE>::Elf_Sym &Sym,
+ uint64_t);
}
}
Modified: lld/trunk/ELF/OutputSections.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/OutputSections.h?rev=261651&r1=261650&r2=261651&view=diff
==============================================================================
--- lld/trunk/ELF/OutputSections.h (original)
+++ lld/trunk/ELF/OutputSections.h Tue Feb 23 10:54:40 2016
@@ -53,6 +53,12 @@ getLocalRelTarget(const ObjectFile<ELFT>
const llvm::object::Elf_Rel_Impl<ELFT, IsRela> &Rel,
typename llvm::object::ELFFile<ELFT>::uintX_t Addend);
+template <class ELFT>
+typename llvm::object::ELFFile<ELFT>::uintX_t
+getLocalTarget(const ObjectFile<ELFT> &File,
+ const typename llvm::object::ELFFile<ELFT>::Elf_Sym &Sym,
+ typename llvm::object::ELFFile<ELFT>::uintX_t Addend);
+
bool canBePreempted(const SymbolBody *Body, bool NeedsGot);
// This represents a section in an output file.
@@ -187,6 +193,7 @@ template <class ELFT> struct DynamicRelo
} OKind;
SymbolBody *Sym = nullptr;
+ uint32_t SymIndex = 0;
InputSectionBase<ELFT> *OffsetSec = nullptr;
uintX_t OffsetInSec = 0;
bool UseSymVA = false;
@@ -207,6 +214,12 @@ template <class ELFT> struct DynamicRelo
OffsetInSec(OffsetInSec), UseSymVA(UseSymVA), Addend(Addend) {}
DynamicReloc(uint32_t Type, InputSectionBase<ELFT> *OffsetSec,
+ uintX_t OffsetInSec, bool UseSymVA, uint32_t SymIndex,
+ uintX_t Addend)
+ : Type(Type), OKind(Off_Sec), SymIndex(SymIndex), OffsetSec(OffsetSec),
+ OffsetInSec(OffsetInSec), UseSymVA(UseSymVA), Addend(Addend) {}
+
+ DynamicReloc(uint32_t Type, InputSectionBase<ELFT> *OffsetSec,
uintX_t OffsetInSec, InputSectionBase<ELFT> *TargetSec,
uintX_t OffsetInTargetSec, uintX_t Addend)
: Type(Type), OKind(Off_Sec), OffsetSec(OffsetSec),
@@ -254,6 +267,7 @@ private:
template <class ELFT>
class RelocationSection final : public OutputSectionBase<ELFT> {
+ typedef typename llvm::object::ELFFile<ELFT>::Elf_Sym Elf_Sym;
typedef typename llvm::object::ELFFile<ELFT>::Elf_Rel Elf_Rel;
typedef typename llvm::object::ELFFile<ELFT>::Elf_Rela Elf_Rela;
typedef typename llvm::object::ELFFile<ELFT>::uintX_t uintX_t;
Modified: lld/trunk/ELF/Target.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Target.cpp?rev=261651&r1=261650&r2=261651&view=diff
==============================================================================
--- lld/trunk/ELF/Target.cpp (original)
+++ lld/trunk/ELF/Target.cpp Tue Feb 23 10:54:40 2016
@@ -182,6 +182,7 @@ public:
unsigned getTlsGotRel(unsigned Type) const override;
bool isTlsDynRel(unsigned Type, const SymbolBody &S) const override;
bool needsCopyRelImpl(uint32_t Type) const override;
+ bool needsDynRelative(unsigned Type) const override;
bool needsGot(uint32_t Type, SymbolBody &S) const override;
PltNeed needsPlt(uint32_t Type, const SymbolBody &S) const override;
void relocateOne(uint8_t *Loc, uint8_t *BufEnd, uint32_t Type, uint64_t P,
@@ -1212,6 +1213,7 @@ void PPC64TargetInfo::relocateOne(uint8_
AArch64TargetInfo::AArch64TargetInfo() {
CopyRel = R_AARCH64_COPY;
+ RelativeRel = R_AARCH64_RELATIVE;
IRelativeRel = R_AARCH64_IRELATIVE;
GotRel = R_AARCH64_GLOB_DAT;
PltRel = R_AARCH64_JUMP_SLOT;
@@ -1319,6 +1321,10 @@ bool AArch64TargetInfo::needsCopyRelImpl
}
}
+bool AArch64TargetInfo::needsDynRelative(unsigned Type) const {
+ return Config->Shared && Type == R_AARCH64_ABS64;
+}
+
bool AArch64TargetInfo::needsGot(uint32_t Type, SymbolBody &S) const {
switch (Type) {
case R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC:
Modified: lld/trunk/ELF/Writer.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Writer.cpp?rev=261651&r1=261650&r2=261651&view=diff
==============================================================================
--- lld/trunk/ELF/Writer.cpp (original)
+++ lld/trunk/ELF/Writer.cpp Tue Feb 23 10:54:40 2016
@@ -311,9 +311,16 @@ void Writer<ELFT>::scanRelocs(
if (handleTlsRelocation<ELFT>(Type, Body, C, RI))
continue;
- if (Target->needsDynRelative(Type))
- Out<ELFT>::RelaDyn->addReloc({Target->RelativeRel, &C, RI.r_offset, true,
- Body, getAddend<ELFT>(RI)});
+ if (Target->needsDynRelative(Type)) {
+ // If Body is null it means the relocation is against a local symbol
+ // and thus we need to pass the local symbol index instead.
+ if (Body)
+ Out<ELFT>::RelaDyn->addReloc({Target->RelativeRel, &C, RI.r_offset, true,
+ Body, getAddend<ELFT>(RI)});
+ else
+ Out<ELFT>::RelaDyn->addReloc({Target->RelativeRel, &C, RI.r_offset, false,
+ SymIndex, getAddend<ELFT>(RI)});
+ }
// MIPS has a special rule to create GOTs for local symbols.
if (Config->EMachine == EM_MIPS && !canBePreempted(Body, true) &&
Added: lld/trunk/test/ELF/aarch64-abs64-dyn.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/aarch64-abs64-dyn.s?rev=261651&view=auto
==============================================================================
--- lld/trunk/test/ELF/aarch64-abs64-dyn.s (added)
+++ lld/trunk/test/ELF/aarch64-abs64-dyn.s Tue Feb 23 10:54:40 2016
@@ -0,0 +1,21 @@
+// REQUIRES: aarch64
+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-linux %s -o %t.o
+
+// Creates a R_AARCH64_ABS64 relocation against _foo. It will be used on a
+// shared object to check for a dynamic relocation creation.
+.globl _foo
+_foo:
+ ret
+_foo_init_array:
+ .xword _foo
+
+// RUN: ld.lld -shared -o %t.so %t.o
+// RUN: llvm-readobj -symbols -dyn-relocations %t.so | FileCheck %s
+
+// CHECK: Dynamic Relocations {
+// CHECK-NEXT: {{.*}} R_AARCH64_RELATIVE - [[FOO_ADDR:[0-9xa-f]+]]
+
+// CHECK: Symbols [
+// CHECK: Symbol {
+// CHECK: Name: _foo
+// CHECK: Value: [[FOO_ADDR]]
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