[lld] r261678 - Fix the aarch64 logic for dynamic relocations.
Rafael Espíndola via llvm-commits
llvm-commits at lists.llvm.org
Wed Feb 24 07:16:27 PST 2016
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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