[lld] r353437 - Fix a bug in R_X86_64_PC{8, 16} relocation handling.
Rui Ueyama via llvm-commits
llvm-commits at lists.llvm.org
Thu Feb 7 13:58:26 PST 2019
These relocations are added after 8.0 was cut, so this is not a regression.
We've been living without these relocations since 4.0, so I think not
supporting this for one more cycle is fine.
On Thu, Feb 7, 2019 at 1:55 PM Shoaib Meenai <smeenai at fb.com> wrote:
> Should this be merged to 8.0?
>
> On 2/7/19, 10:12 AM, "llvm-commits on behalf of Rui Ueyama via
> llvm-commits" <llvm-commits-bounces at lists.llvm.org on behalf of
> llvm-commits at lists.llvm.org> wrote:
>
> Author: ruiu
> Date: Thu Feb 7 10:12:57 2019
> New Revision: 353437
>
> URL:
> https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject-3Frev-3D353437-26view-3Drev&d=DwIGaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=o3kDXzdBUE3ljQXKeTWOMw&m=SsIV4bxzRk5xcqIODXUWMAKgrjALt2jgK-8molEY6ik&s=cXPyCTPqI-n63UfUmlWURBOeqMLYWXWNr7J7MBI2A9k&e=
> Log:
> Fix a bug in R_X86_64_PC{8,16} relocation handling.
>
> R_X86_64_PC{8,16} relocations are sign-extended, so when we check
> for relocation overflow, we had to use checkInt instead of checkUInt.
> I confirmed that GNU linkers create the same output for the test case.
>
> Added:
> lld/trunk/test/ELF/Inputs/x86-64-pcrel.s
> Modified:
> lld/trunk/ELF/Arch/X86_64.cpp
> lld/trunk/test/ELF/x86-64-pcrel.s
>
> Modified: lld/trunk/ELF/Arch/X86_64.cpp
> URL:
> https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_lld_trunk_ELF_Arch_X86-5F64.cpp-3Frev-3D353437-26r1-3D353436-26r2-3D353437-26view-3Ddiff&d=DwIGaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=o3kDXzdBUE3ljQXKeTWOMw&m=SsIV4bxzRk5xcqIODXUWMAKgrjALt2jgK-8molEY6ik&s=1z6MXm9dyJ34rii6Pnpfo2Z6p1hjqOVNa5a6HMGyHKs&e=
>
> ==============================================================================
> --- lld/trunk/ELF/Arch/X86_64.cpp (original)
> +++ lld/trunk/ELF/Arch/X86_64.cpp Thu Feb 7 10:12:57 2019
> @@ -324,15 +324,21 @@ template <class ELFT>
> void X86_64<ELFT>::relocateOne(uint8_t *Loc, RelType Type, uint64_t
> Val) const {
> switch (Type) {
> case R_X86_64_8:
> - case R_X86_64_PC8:
> checkUInt(Loc, Val, 8, Type);
> *Loc = Val;
> break;
> + case R_X86_64_PC8:
> + checkInt(Loc, Val, 8, Type);
> + *Loc = Val;
> + break;
> case R_X86_64_16:
> - case R_X86_64_PC16:
> checkUInt(Loc, Val, 16, Type);
> write16le(Loc, Val);
> break;
> + case R_X86_64_PC16:
> + checkInt(Loc, Val, 16, Type);
> + write16le(Loc, Val);
> + break;
> case R_X86_64_32:
> checkUInt(Loc, Val, 32, Type);
> write32le(Loc, Val);
>
> Added: lld/trunk/test/ELF/Inputs/x86-64-pcrel.s
> URL:
> https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_lld_trunk_test_ELF_Inputs_x86-2D64-2Dpcrel.s-3Frev-3D353437-26view-3Dauto&d=DwIGaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=o3kDXzdBUE3ljQXKeTWOMw&m=SsIV4bxzRk5xcqIODXUWMAKgrjALt2jgK-8molEY6ik&s=SSJnKLh-SoIbbcSN6izHhnGL8HVY9OQ0-DjTN8xdCaM&e=
>
> ==============================================================================
> --- lld/trunk/test/ELF/Inputs/x86-64-pcrel.s (added)
> +++ lld/trunk/test/ELF/Inputs/x86-64-pcrel.s Thu Feb 7 10:12:57 2019
> @@ -0,0 +1,8 @@
> +.globl foo
> +foo:
> +
> +.word _start - foo
> +.fill 14,1,0xcc
> +
> +.byte _start - foo
> +.fill 15,1,0xcc
>
> Modified: lld/trunk/test/ELF/x86-64-pcrel.s
> URL:
> https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_lld_trunk_test_ELF_x86-2D64-2Dpcrel.s-3Frev-3D353437-26r1-3D353436-26r2-3D353437-26view-3Ddiff&d=DwIGaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=o3kDXzdBUE3ljQXKeTWOMw&m=SsIV4bxzRk5xcqIODXUWMAKgrjALt2jgK-8molEY6ik&s=KwH6YCrVh-2BtX_A9zDtFgiZ15ayv1TbU-56rwu-XO0&e=
>
> ==============================================================================
> --- lld/trunk/test/ELF/x86-64-pcrel.s (original)
> +++ lld/trunk/test/ELF/x86-64-pcrel.s Thu Feb 7 10:12:57 2019
> @@ -3,13 +3,15 @@
> // This is a test for R_X86_64_PC8 and R_X86_64_PC16.
>
> // RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t1.o
> -// RUN: echo '.globl foo; foo:' | llvm-mc -filetype=obj
> -triple=x86_64-pc-linux - -o %t2.o
> +// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux
> %p/Inputs/x86-64-pcrel.s -o %t2.o
> // RUN: ld.lld -o %t.exe %t1.o %t2.o
> // RUN: llvm-objdump -s %t.exe | FileCheck %s
>
> -// CHECK: Contents of section .text:
> -// CHECK: 2000cccc cccccccc cccccccc cccccccc
> -// CHECK: 20cccccc cccccccc cccccccc cccccccc
> +// CHECK: Contents of section .text:
> +// CHECK-NEXT: 2000cccc cccccccc cccccccc cccccccc
> +// CHECK-NEXT: 20cccccc cccccccc cccccccc cccccccc
> +// CHECK-NEXT: e0ffcccc cccccccc cccccccc cccccccc
> +// CHECK-NEXT: e0cccccc cccccccc cccccccc cccccccc
>
> .globl _start
> _start:
>
>
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