[lld] r261678 - Fix the aarch64 logic for dynamic relocations.
Adhemerval Zanella via llvm-commits
llvm-commits at lists.llvm.org
Wed Feb 24 06:43:58 PST 2016
I am getting shared library dynamic relocations issues since this 'fix'
for aarch64:
$ cat tls_test.h
#ifndef TLS_TEST_H
# define TLS_TEST_H
int f1 ();
int f2 ();
extern int __thread o1;
#endif
$ cat tls_shared.c
#include "tls_test.h"
int v1;
int v2 = 5;
int f1 ()
{
return v1;
}
int f2 ()
{
return v2;
}
__thread int o1 = 7;
$ cat tls_main.c
#include <assert.h>
#include "tls_test.h"
int main ()
{
// Run the tests.
assert(f1() == 0);
assert(f2() == 5);
assert(o1 == 7);
return 0;
}
$ clang -Wall -O3 -target aarch64-linux-gnu -fpic -c -o tls_shared.o tls_shared.c
$ clang -target aarch64-linux-gnu -shared -Wl,-soname,libtls_test.so tls_shared.o -o libtls_test.so
$ clang -Wall -O3 -target aarch64-linux-gnu -c -o tls_main.o tls_main.c
$ clang -Wall -O3 -target aarch64-linux-gnu tls_main.o -o tls_main -pthread -L`pwd` -ltls_test
$ LD_LIBRARY_PATH=. ./tls_main
Segmentation fault (core dumped)
$ gdb ./tls_main
(gdb) set env LD_LIBRARY_PATH=.
(gdb) r
Starting program: /home/adhemerval.zanella/llvm/tls/test02/tls_main
Program received signal SIGSEGV, Segmentation fault.
0x0000007fb7fdd194 in elf_machine_rela (reloc=0x7fb7ff6540, reloc=0x7fb7ff6540, skip_ifunc=<optimized out>, reloc_addr_arg=0x7fb7ff7124, version=0x0, sym=0x7fb7ff6238,
map=0x7fb7ffb5b0) at ../sysdeps/aarch64/dl-machine.h:242
242 ../sysdeps/aarch64/dl-machine.h: No such file or directory.
It is creating a lot of bogus R_AARCH64_RELATIVE relocations:
$ objdump -R libtls_test.so
libtls_test.so: file format elf64-littleaarch64
DYNAMIC RELOCATION RECORDS
OFFSET TYPE VALUE
0000000000002170 R_AARCH64_GLOB_DAT __gmon_start__
0000000000001124 R_AARCH64_RELATIVE *ABS*+0x0000000000001000
0000000000001014 R_AARCH64_RELATIVE *ABS*+0x0000000000003010
0000000000001018 R_AARCH64_RELATIVE *ABS*+0x0000000000003010
000000000000101c R_AARCH64_RELATIVE *ABS*+0x0000000000003010
0000000000001020 R_AARCH64_RELATIVE *ABS*+0x0000000000003010
0000000000002178 R_AARCH64_GLOB_DAT _ITM_deregisterTMCloneTable
0000000000001048 R_AARCH64_RELATIVE *ABS*+0x0000000000003010
000000000000104c R_AARCH64_RELATIVE *ABS*+0x0000000000003010
0000000000001050 R_AARCH64_RELATIVE *ABS*+0x0000000000003010
0000000000001054 R_AARCH64_RELATIVE *ABS*+0x0000000000003010
0000000000002180 R_AARCH64_GLOB_DAT _ITM_registerTMCloneTable
000000000000108c R_AARCH64_RELATIVE *ABS*+0x0000000000003038
0000000000001090 R_AARCH64_RELATIVE *ABS*+0x0000000000003038
0000000000002188 R_AARCH64_GLOB_DAT __cxa_finalize
00000000000010a4 R_AARCH64_RELATIVE *ABS*+0x0000000000003000
00000000000010a8 R_AARCH64_RELATIVE *ABS*+0x0000000000003000
00000000000010b8 R_AARCH64_RELATIVE *ABS*+0x0000000000003038
00000000000010cc R_AARCH64_RELATIVE *ABS*+0x0000000000002008
00000000000010d4 R_AARCH64_RELATIVE *ABS*+0x0000000000002008
0000000000002190 R_AARCH64_GLOB_DAT _Jv_RegisterClasses
0000000000003000 R_AARCH64_RELATIVE *ABS*+0x0000000000003000
0000000000002010 R_AARCH64_RELATIVE *ABS*+0x0000000000001080
0000000000002018 R_AARCH64_RELATIVE *ABS*+0x00000000000010c8
0000000000002198 R_AARCH64_GLOB_DAT v1
00000000000021a0 R_AARCH64_GLOB_DAT v2
0000000000003028 R_AARCH64_JUMP_SLOT __gmon_start__
0000000000003030 R_AARCH64_JUMP_SLOT __cxa_finalize
Where we should expect only three:
$ objdump -R libtls_test-gcc.so
libtls_test-gcc.so: file format elf64-littleaarch64
DYNAMIC RELOCATION RECORDS
OFFSET TYPE VALUE
0000000000010dc0 R_AARCH64_RELATIVE *ABS*+0x00000000000007e8
0000000000010dc8 R_AARCH64_RELATIVE *ABS*+0x00000000000007a0
0000000000011010 R_AARCH64_RELATIVE *ABS*+0x0000000000011010
These are the init_array one against <frame_dummy> (0x7e8),
<__do_global_dtors_aux> (0x7a0), and <__dso_handle> (0x11010)
On 23-02-2016 17:19, Rafael Espindola via llvm-commits wrote:
> Author: rafael
> Date: Tue Feb 23 14:19:44 2016
> New Revision: 261678
>
> URL: http://llvm.org/viewvc/llvm-project?rev=261678&view=rev
> Log:
> Fix the aarch64 logic for dynamic relocations.
>
> There is nothing aarch64 specific in here. If a symbol can be preempted,
> we need to copy the full relocation to the dynamic linker.
>
> If a symbol cannot be preempted, we can make the dynamic linker life
> easier and produce a relative relocation.
>
> This is directly equivalent to R_X86_64_64 to R_x86_64_RELATIVE
> conversion.
>
> Modified:
> lld/trunk/ELF/OutputSections.cpp
> lld/trunk/ELF/OutputSections.h
> lld/trunk/ELF/Target.cpp
> lld/trunk/ELF/Writer.cpp
> lld/trunk/test/ELF/aarch64-abs64-dyn.s
>
> Modified: lld/trunk/ELF/OutputSections.cpp
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/OutputSections.cpp?rev=261678&r1=261677&r2=261678&view=diff
> ==============================================================================
> --- lld/trunk/ELF/OutputSections.cpp (original)
> +++ lld/trunk/ELF/OutputSections.cpp Tue Feb 23 14:19:44 2016
> @@ -253,18 +253,11 @@ 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;
> }
>
> @@ -869,6 +862,7 @@ 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.
> @@ -881,22 +875,10 @@ elf2::getLocalRelTarget(const ObjectFile
> if (!Sym)
> fatal("Unsupported relocation without symbol");
>
> - 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;
> + InputSectionBase<ELFT> *Section = File.getSection(*Sym);
>
> - 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
> @@ -906,8 +888,8 @@ elf2::getLocalTarget(const ObjectFile<EL
> 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;
> }
> @@ -1665,18 +1647,5 @@ 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=261678&r1=261677&r2=261678&view=diff
> ==============================================================================
> --- lld/trunk/ELF/OutputSections.h (original)
> +++ lld/trunk/ELF/OutputSections.h Tue Feb 23 14:19:44 2016
> @@ -53,12 +53,6 @@ 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.
> @@ -193,7 +187,6 @@ template <class ELFT> struct DynamicRelo
> } OKind;
>
> SymbolBody *Sym = nullptr;
> - uint32_t SymIndex = 0;
> InputSectionBase<ELFT> *OffsetSec = nullptr;
> uintX_t OffsetInSec = 0;
> bool UseSymVA = false;
> @@ -214,12 +207,6 @@ 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),
> @@ -267,7 +254,6 @@ 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=261678&r1=261677&r2=261678&view=diff
> ==============================================================================
> --- lld/trunk/ELF/Target.cpp (original)
> +++ lld/trunk/ELF/Target.cpp Tue Feb 23 14:19:44 2016
> @@ -181,8 +181,8 @@ public:
> int32_t Index, unsigned RelOff) const override;
> unsigned getTlsGotRel(unsigned Type) const override;
> bool isTlsDynRel(unsigned Type, const SymbolBody &S) const override;
> + bool isRelRelative(uint32_t Type) 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,
> @@ -1209,6 +1209,8 @@ AArch64TargetInfo::AArch64TargetInfo() {
> PltZeroSize = 32;
> }
>
> +bool AArch64TargetInfo::isRelRelative(uint32_t Type) const { return false; }
> +
> bool AArch64TargetInfo::isTlsGlobalDynamicRel(unsigned Type) const {
> return Type == R_AARCH64_TLSDESC_ADR_PAGE21 ||
> Type == R_AARCH64_TLSDESC_LD64_LO12_NC ||
> @@ -1305,10 +1307,6 @@ 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=261678&r1=261677&r2=261678&view=diff
> ==============================================================================
> --- lld/trunk/ELF/Writer.cpp (original)
> +++ lld/trunk/ELF/Writer.cpp Tue Feb 23 14:19:44 2016
> @@ -311,16 +311,9 @@ void Writer<ELFT>::scanRelocs(
> if (handleTlsRelocation<ELFT>(Type, Body, C, RI))
> continue;
>
> - 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)});
> - }
> + if (Target->needsDynRelative(Type))
> + Out<ELFT>::RelaDyn->addReloc({Target->RelativeRel, &C, RI.r_offset, true,
> + Body, getAddend<ELFT>(RI)});
>
> // MIPS has a special rule to create GOTs for local symbols.
> if (Config->EMachine == EM_MIPS && !canBePreempted(Body, true) &&
>
> Modified: lld/trunk/test/ELF/aarch64-abs64-dyn.s
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/aarch64-abs64-dyn.s?rev=261678&r1=261677&r2=261678&view=diff
> ==============================================================================
> --- lld/trunk/test/ELF/aarch64-abs64-dyn.s (original)
> +++ lld/trunk/test/ELF/aarch64-abs64-dyn.s Tue Feb 23 14:19:44 2016
> @@ -1,21 +1,27 @@
> // 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
> +// Creates a R_AARCH64_ABS64 relocation against foo and bar
> + .globl foo
> +foo:
> +
> + .global bar
> + .hidden bar
> +bar:
> +
> + .data
> + .xword foo
> + .xword bar
>
> // 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: Dynamic Relocations {
> +// CHECK-NEXT: {{.*}} R_AARCH64_ABS64 foo 0x0
> +// CHECK-NEXT: {{.*}} R_AARCH64_RELATIVE - [[BAR_ADDR:.*]]
> +// CHECK-NEXT: }
>
> -// CHECK: Symbols [
> -// CHECK: Symbol {
> -// CHECK: Name: _foo
> -// CHECK: Value: [[FOO_ADDR]]
> +// CHECK: Symbols [
> +// CHECK: Symbol {
> +// CHECK: Name: bar
> +// CHECK-NEXT: Value: [[BAR_ADDR]]
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
More information about the llvm-commits
mailing list