[lld] r261678 - Fix the aarch64 logic for dynamic relocations.
Rafael Espíndola via llvm-commits
llvm-commits at lists.llvm.org
Wed Feb 24 07:58:20 PST 2016
OK, this reduces to just
.Lfoo:
.rodata
.long .Lfoo - .
fixing.
Cheers,
Rafael
On 24 February 2016 at 10:37, Adhemerval Zanella
<adhemerval.zanella at linaro.org> wrote:
> I am linking against default gcc-4.9 files from Ubuntu 15.04.
>
> On 24-02-2016 12:16, Rafael Espíndola wrote:
>> Can you attach (os post somewhere) the following files:
>>
>> crtbeginS.o
>> crti.o
>> crtendS.o
>> libgcc.so
>> libgcc_s.so
>> libc.so (this may be a script, in which case I need the files it includes)
>> crtn.o
>>
>> Thanks,
>> Rafael
>>
>>
>>
>>
>> On 24 February 2016 at 09:43, Adhemerval Zanella
>> <adhemerval.zanella at linaro.org> wrote:
>>> 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]]
>>>>
>>>>
>>>> _______________________________________________
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