[lld] r251998 - [elf2] Implement R_X86_64_TPOFF32.
Rafael Espíndola via llvm-commits
llvm-commits at lists.llvm.org
Wed Nov 4 16:32:59 PST 2015
I just noticed that I am getting different results with gold and bfd:
Given:
-------------------------------
.global _start
_start:
movl %fs:a at tpoff, %eax
.global a
.section .tbss,"awT", at nobits
.zero 0x10
a:
.long 0
----------------------------------
lld produces
_start:
11000: 64 8b 04 25 10 00 00 00 movl %fs:16, %eax
gold produces
_start:
4000e8: 64 8b 04 25 fc ff ff ff movl %fs:-4, %eax
Is that expected?
Cheers,
Rafael
On 3 November 2015 at 17:39, Michael J. Spencer via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
> Author: mspencer
> Date: Tue Nov 3 16:39:09 2015
> New Revision: 251998
>
> URL: http://llvm.org/viewvc/llvm-project?rev=251998&view=rev
> Log:
> [elf2] Implement R_X86_64_TPOFF32.
>
> This does not support TPOFF32 relocations to local symbols as the address calculations are separate. Support for this will be a separate patch.
>
> Modified:
> lld/trunk/ELF/OutputSections.cpp
> lld/trunk/ELF/OutputSections.h
> lld/trunk/ELF/Target.cpp
> lld/trunk/ELF/Writer.cpp
> lld/trunk/test/elf2/tls.s
>
> Modified: lld/trunk/ELF/OutputSections.cpp
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/OutputSections.cpp?rev=251998&r1=251997&r2=251998&view=diff
> ==============================================================================
> --- lld/trunk/ELF/OutputSections.cpp (original)
> +++ lld/trunk/ELF/OutputSections.cpp Tue Nov 3 16:39:09 2015
> @@ -644,6 +644,9 @@ typename ELFFile<ELFT>::uintX_t lld::elf
> case SymbolBody::DefinedRegularKind: {
> const auto &DR = cast<DefinedRegular<ELFT>>(S);
> InputSectionBase<ELFT> &SC = DR.Section;
> + if (DR.Sym.getType() == STT_TLS)
> + return SC.OutSec->getVA() + SC.getOffset(DR.Sym) -
> + Out<ELFT>::TlsInitImageVA;
> return SC.OutSec->getVA() + SC.getOffset(DR.Sym);
> }
> case SymbolBody::DefinedCommonKind:
>
> Modified: lld/trunk/ELF/OutputSections.h
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/OutputSections.h?rev=251998&r1=251997&r2=251998&view=diff
> ==============================================================================
> --- lld/trunk/ELF/OutputSections.h (original)
> +++ lld/trunk/ELF/OutputSections.h Tue Nov 3 16:39:09 2015
> @@ -353,6 +353,7 @@ private:
> // globally accessible. Writer initializes them, so don't use them
> // until Writer is initialized.
> template <class ELFT> struct Out {
> + typedef typename llvm::object::ELFFile<ELFT>::uintX_t uintX_t;
> static DynamicSection<ELFT> *Dynamic;
> static GnuHashTableSection<ELFT> *GnuHashTab;
> static GotPltSection<ELFT> *GotPlt;
> @@ -370,6 +371,7 @@ template <class ELFT> struct Out {
> static StringTableSection<ELFT> *StrTab;
> static SymbolTableSection<ELFT> *DynSymTab;
> static SymbolTableSection<ELFT> *SymTab;
> + static uintX_t TlsInitImageVA;
> };
>
> template <class ELFT> DynamicSection<ELFT> *Out<ELFT>::Dynamic;
> @@ -389,6 +391,7 @@ template <class ELFT> StringTableSection
> template <class ELFT> StringTableSection<ELFT> *Out<ELFT>::StrTab;
> template <class ELFT> SymbolTableSection<ELFT> *Out<ELFT>::DynSymTab;
> template <class ELFT> SymbolTableSection<ELFT> *Out<ELFT>::SymTab;
> +template <class ELFT> typename Out<ELFT>::uintX_t Out<ELFT>::TlsInitImageVA;
> }
> }
> #endif
>
> Modified: lld/trunk/ELF/Target.cpp
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Target.cpp?rev=251998&r1=251997&r2=251998&view=diff
> ==============================================================================
> --- lld/trunk/ELF/Target.cpp (original)
> +++ lld/trunk/ELF/Target.cpp Tue Nov 3 16:39:09 2015
> @@ -339,6 +339,9 @@ void X86_64TargetInfo::relocateOne(uint8
> error("R_X86_64_32S out of range");
> write32le(Loc, SA);
> break;
> + case R_X86_64_TPOFF32:
> + write32le(Loc, SA);
> + break;
> default:
> error("unrecognized reloc " + Twine(Type));
> }
>
> Modified: lld/trunk/ELF/Writer.cpp
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Writer.cpp?rev=251998&r1=251997&r2=251998&view=diff
> ==============================================================================
> --- lld/trunk/ELF/Writer.cpp (original)
> +++ lld/trunk/ELF/Writer.cpp Tue Nov 3 16:39:09 2015
> @@ -716,8 +716,10 @@ template <class ELFT> void Writer<ELFT>:
> }
>
> if ((Sec->getFlags() & SHF_ALLOC) && (Sec->getFlags() & SHF_TLS)) {
> - if (!TlsPhdr.p_vaddr)
> + if (!TlsPhdr.p_vaddr) {
> setPhdr(&TlsPhdr, PT_TLS, PF_R, FileOff, VA, 0, Sec->getAlign());
> + Out<ELFT>::TlsInitImageVA = VA;
> + }
> if (Sec->getType() != SHT_NOBITS)
> VA = RoundUpToAlignment(VA, Sec->getAlign());
> uintX_t TVA = RoundUpToAlignment(VA + ThreadBSSOffset, Sec->getAlign());
>
> Modified: lld/trunk/test/elf2/tls.s
> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/elf2/tls.s?rev=251998&r1=251997&r2=251998&view=diff
> ==============================================================================
> --- lld/trunk/test/elf2/tls.s (original)
> +++ lld/trunk/test/elf2/tls.s Tue Nov 3 16:39:09 2015
> @@ -1,21 +1,34 @@
> // REQUIRES: x86
> // RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
> // RUN: ld.lld2 %t -o %tout
> -// RUN: llvm-readobj -sections -program-headers %tout | FileCheck %s
> +// RUN: llvm-readobj -symbols -sections -program-headers %tout | FileCheck %s
> +// RUN: llvm-objdump -d %tout | FileCheck %s --check-prefix=DIS
>
> .global _start
> _start:
> + movl %fs:a at tpoff, %eax
> + movl %fs:b at tpoff, %eax
> + movl %fs:c at tpoff, %eax
> + movl %fs:d at tpoff, %eax
>
> + .global a
> .section .tbss,"awT", at nobits
> +a:
> .long 0
>
> + .global b
> .section .tdata,"awT", at progbits
> +b:
> .long 1
>
> + .global c
> .section .thread_bss,"awT", at nobits
> +c:
> .long 0
>
> + .global d
> .section .thread_data,"awT", at progbits
> +d:
> .long 2
>
> // CHECK: Name: .tdata
> @@ -77,9 +90,9 @@ _start:
> // CHECK-NEXT: SHF_WRITE
> // CHECK-NEXT: ]
>
> -// 0x1100C = TBSS_ADDR + 4
> +// 0x1200C = TBSS_ADDR + 4
>
> -// CHECK-NEXT: Address: 0x1100C
> +// CHECK-NEXT: Address: 0x1200C
> // CHECK-NEXT: Offset:
> // CHECK-NEXT: Size: 4
> // CHECK-NEXT: Link:
> @@ -88,11 +101,49 @@ _start:
> // CHECK-NEXT: EntrySize:
> // CHECK-NEXT: }
>
> +// CHECK: Symbols [
> +// CHECK: Name: a
> +// CHECK-NEXT: Value: 0x8
> +// CHECK-NEXT: Size:
> +// CHECK-NEXT: Binding: Global
> +// CHECK-NEXT: Type: TLS
> +// CHECK-NEXT: Other: 0
> +// CHECK-NEXT: Section: .tbss
> +// CHECK-NEXT: }
> +// CHECK-NEXT: Symbol {
> +// CHECK-NEXT: Name: b
> +// CHECK-NEXT: Value: 0x0
> +// CHECK-NEXT: Size:
> +// CHECK-NEXT: Binding: Global
> +// CHECK-NEXT: Type: TLS
> +// CHECK-NEXT: Other: 0
> +// CHECK-NEXT: Section: .tdata
> +// CHECK-NEXT: }
> +// CHECK-NEXT: Symbol {
> +// CHECK-NEXT: Name: c
> +// CHECK-NEXT: Value: 0xC
> +// CHECK-NEXT: Size:
> +// CHECK-NEXT: Binding: Global
> +// CHECK-NEXT: Type: TLS
> +// CHECK-NEXT: Other: 0
> +// CHECK-NEXT: Section: .thread_bss
> +// CHECK-NEXT: }
> +// CHECK-NEXT: Symbol {
> +// CHECK-NEXT: Name: d
> +// CHECK-NEXT: Value: 0x4
> +// CHECK-NEXT: Size:
> +// CHECK-NEXT: Binding: Global
> +// CHECK-NEXT: Type: TLS
> +// CHECK-NEXT: Other: 0
> +// CHECK-NEXT: Section: .thread_data
> +// CHECK-NEXT: }
> +
> // Check that the TLS NOBITS sections weren't added to the R/W PT_LOAD's size.
>
> // CHECK: ProgramHeaders [
> // CHECK: Type: PT_LOAD
> // CHECK: Type: PT_LOAD
> +// CHECK: Type: PT_LOAD
> // CHECK: FileSize: 8
> // CHECK-NEXT: MemSize: 8
> // CHECK-NEXT: Flags [
> @@ -110,3 +161,10 @@ _start:
> // CHECK-NEXT: ]
> // CHECK-NEXT: Alignment:
> // CHECK-NEXT: }
> +
> +// DIS: Disassembly of section .text:
> +// DIS-NEXT: _start:
> +// DIS-NEXT: 11000: {{.+}} movl %fs:8, %eax
> +// DIS-NEXT: 11008: {{.+}} movl %fs:0, %eax
> +// DIS-NEXT: 11010: {{.+}} movl %fs:12, %eax
> +// DIS-NEXT: 11018: {{.+}} movl %fs:4, %eax
>
>
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