[lld] r276172 - [ELF][MIPS] Pick arch flag from the first input file.

Rui Ueyama via llvm-commits llvm-commits at lists.llvm.org
Wed Jul 20 13:29:48 PDT 2016


On Wed, Jul 20, 2016 at 4:15 PM, Simon Atanasyan via llvm-commits <
llvm-commits at lists.llvm.org> wrote:

> Author: atanasyan
> Date: Wed Jul 20 15:15:24 2016
> New Revision: 276172
>
> URL: http://llvm.org/viewvc/llvm-project?rev=276172&view=rev
> Log:
> [ELF][MIPS] Pick arch flag from the first input file.
>
> LLD still does not produce a correct combination of MIPS ELF flags if
> input files have different sets of ELF flags (i.e. EF_MIPS_ARCH_32 and
> EF_MIPS_ARCH_32R2). But now we do not stick to "R2" ABI version and can
> emit EF_MIPS_ARCH_32R6 for example.
>
> Modified:
>     lld/trunk/ELF/Writer.cpp
>     lld/trunk/test/ELF/basic-mips.s
>     lld/trunk/test/ELF/emulation.s
>     lld/trunk/test/ELF/mips-elf-flags.s
>
> Modified: lld/trunk/ELF/Writer.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Writer.cpp?rev=276172&r1=276171&r2=276172&view=diff
>
> ==============================================================================
> --- lld/trunk/ELF/Writer.cpp (original)
> +++ lld/trunk/ELF/Writer.cpp Wed Jul 20 15:15:24 2016
> @@ -1166,16 +1166,22 @@ template <class ELFT> void Writer<ELFT>:
>    }
>  }
>
> -static uint32_t getMipsEFlags(bool Is64Bits) {
> -  // FIXME: In fact ELF flags depends on ELF flags of input object files
> -  // and selected emulation. For now just use hard coded values.
> +template <class ELFT>
> +static uint32_t getMipsEFlags(bool Is64Bits,
> +                              const ELFFileBase<ELFT> &FirstElf) {


You can omit Is64Bits parameter because you can use ELFT::Is64Bits in this
function instead. Moreover, you can omit FirstElf because it can be
accessed through Config->FirstrObj.

+  // FIXME: ELF flags depends on ELF flags of all input object files and
> +  // selected emulation. For now pick the arch flag from the fisrt input
> file
> +  // and use hard coded values for other flags.
> +  uint32_t FirstElfFlags = FirstElf.getObj().getHeader()->e_flags;
> +  uint32_t ElfFlags = FirstElfFlags & EF_MIPS_ARCH;
>    if (Is64Bits)
> -    return EF_MIPS_CPIC | EF_MIPS_PIC | EF_MIPS_ARCH_64R2;
> -
> -  uint32_t V = EF_MIPS_CPIC | EF_MIPS_ABI_O32 | EF_MIPS_ARCH_32R2;
> -  if (Config->Shared)
> -    V |= EF_MIPS_PIC;
> -  return V;
> +    ElfFlags |= EF_MIPS_CPIC | EF_MIPS_PIC;
> +  else {
> +    ElfFlags |= EF_MIPS_CPIC | EF_MIPS_ABI_O32;
> +    if (Config->Shared)
> +      ElfFlags |= EF_MIPS_PIC;
> +  }
> +  return ElfFlags;
>  }
>
>  template <class ELFT> static typename ELFT::uint getEntryAddr() {
> @@ -1252,7 +1258,7 @@ template <class ELFT> void Writer<ELFT>:
>    EHdr->e_shstrndx = Out<ELFT>::ShStrTab->SectionIndex;
>
>    if (Config->EMachine == EM_MIPS)
> -    EHdr->e_flags = getMipsEFlags(ELFT::Is64Bits);
> +    EHdr->e_flags = getMipsEFlags(ELFT::Is64Bits, FirstObj);
>
>    if (!Config->Relocatable) {
>      EHdr->e_phoff = sizeof(Elf_Ehdr);
>
> Modified: lld/trunk/test/ELF/basic-mips.s
> URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/basic-mips.s?rev=276172&r1=276171&r2=276172&view=diff
>
> ==============================================================================
> --- lld/trunk/test/ELF/basic-mips.s (original)
> +++ lld/trunk/test/ELF/basic-mips.s Wed Jul 20 15:15:24 2016
> @@ -30,7 +30,7 @@ __start:
>  # CHECK-NEXT:   SectionHeaderOffset: 0x30088
>  # CHECK-NEXT:   Flags [
>  # CHECK-NEXT:     EF_MIPS_ABI_O32
> -# CHECK-NEXT:     EF_MIPS_ARCH_32R2
> +# CHECK-NEXT:     EF_MIPS_ARCH_32
>  # CHECK-NEXT:     EF_MIPS_CPIC
>  # CHECK-NEXT:   ]
>  # CHECK-NEXT:   HeaderSize: 52
>
> Modified: lld/trunk/test/ELF/emulation.s
> URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/emulation.s?rev=276172&r1=276171&r2=276172&view=diff
>
> ==============================================================================
> --- lld/trunk/test/ELF/emulation.s (original)
> +++ lld/trunk/test/ELF/emulation.s Wed Jul 20 15:15:24 2016
> @@ -176,7 +176,7 @@
>  # MIPS-NEXT:   SectionHeaderOffset:
>  # MIPS-NEXT:   Flags [
>  # MIPS-NEXT:     EF_MIPS_ABI_O32
> -# MIPS-NEXT:     EF_MIPS_ARCH_32R2
> +# MIPS-NEXT:     EF_MIPS_ARCH_32
>  # MIPS-NEXT:     EF_MIPS_CPIC
>  # MIPS-NEXT:   ]
>
> @@ -205,7 +205,7 @@
>  # MIPSEL-NEXT:   SectionHeaderOffset:
>  # MIPSEL-NEXT:   Flags [
>  # MIPSEL-NEXT:     EF_MIPS_ABI_O32
> -# MIPSEL-NEXT:     EF_MIPS_ARCH_32R2
> +# MIPSEL-NEXT:     EF_MIPS_ARCH_32
>  # MIPSEL-NEXT:     EF_MIPS_CPIC
>  # MIPSEL-NEXT:   ]
>
> @@ -231,7 +231,7 @@
>  # MIPS64-NEXT:   ProgramHeaderOffset: 0x40
>  # MIPS64-NEXT:   SectionHeaderOffset:
>  # MIPS64-NEXT:   Flags [
> -# MIPS64-NEXT:     EF_MIPS_ARCH_64R2
> +# MIPS64-NEXT:     EF_MIPS_ARCH_64
>  # MIPS64-NEXT:     EF_MIPS_CPIC
>  # MIPS64-NEXT:     EF_MIPS_PIC
>  # MIPS64-NEXT:   ]
> @@ -258,7 +258,7 @@
>  # MIPS64EL-NEXT:   ProgramHeaderOffset: 0x40
>  # MIPS64EL-NEXT:   SectionHeaderOffset:
>  # MIPS64EL-NEXT:   Flags [
> -# MIPS64EL-NEXT:     EF_MIPS_ARCH_64R2
> +# MIPS64EL-NEXT:     EF_MIPS_ARCH_64
>  # MIPS64EL-NEXT:     EF_MIPS_CPIC
>  # MIPS64EL-NEXT:     EF_MIPS_PIC
>  # MIPS64EL-NEXT:   ]
>
> Modified: lld/trunk/test/ELF/mips-elf-flags.s
> URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/mips-elf-flags.s?rev=276172&r1=276171&r2=276172&view=diff
>
> ==============================================================================
> --- lld/trunk/test/ELF/mips-elf-flags.s (original)
> +++ lld/trunk/test/ELF/mips-elf-flags.s Wed Jul 20 15:15:24 2016
> @@ -5,6 +5,14 @@
>  # RUN: llvm-readobj -h %t.so | FileCheck -check-prefix=SO %s
>  # RUN: ld.lld %t.o -o %t.exe
>  # RUN: llvm-readobj -h %t.exe | FileCheck -check-prefix=EXE %s
> +# RUN: llvm-mc -filetype=obj -triple=mips-unknown-linux \
> +# RUN:         -mcpu=mips32r2 %s -o %t-r2.o
> +# RUN: ld.lld %t-r2.o -o %t-r2.exe
> +# RUN: llvm-readobj -h %t-r2.exe | FileCheck -check-prefix=EXE-R2 %s
> +# RUN: llvm-mc -filetype=obj -triple=mips-unknown-linux \
> +# RUN:         -mcpu=mips32r6 %s -o %t-r6.o
> +# RUN: ld.lld %t-r6.o -o %t-r6.exe
> +# RUN: llvm-readobj -h %t-r6.exe | FileCheck -check-prefix=EXE-R6 %s
>
>  # REQUIRES: mips
>
> @@ -15,13 +23,25 @@ __start:
>
>  # SO:      Flags [
>  # SO-NEXT:   EF_MIPS_ABI_O32
> -# SO-NEXT:   EF_MIPS_ARCH_32R2
> +# SO-NEXT:   EF_MIPS_ARCH_32
>  # SO-NEXT:   EF_MIPS_CPIC
>  # SO-NEXT:   EF_MIPS_PIC
>  # SO-NEXT: ]
>
>  # EXE:      Flags [
>  # EXE-NEXT:   EF_MIPS_ABI_O32
> -# EXE-NEXT:   EF_MIPS_ARCH_32R2
> +# EXE-NEXT:   EF_MIPS_ARCH_32
>  # EXE-NEXT:   EF_MIPS_CPIC
>  # EXE-NEXT: ]
> +
> +# EXE-R2:      Flags [
> +# EXE-R2-NEXT:   EF_MIPS_ABI_O32
> +# EXE-R2-NEXT:   EF_MIPS_ARCH_32R2
> +# EXE-R2-NEXT:   EF_MIPS_CPIC
> +# EXE-R2-NEXT: ]
> +
> +# EXE-R6:      Flags [
> +# EXE-R6-NEXT:   EF_MIPS_ABI_O32
> +# EXE-R6-NEXT:   EF_MIPS_ARCH_32R6
> +# EXE-R6-NEXT:   EF_MIPS_CPIC
> +# EXE-R6-NEXT: ]
>
>
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