[PATCH] D31255: Force @{init, fini}_array if section name starts with ".{init, fini}_array.".

[Rafael Avila de Espindola via llvm-commits]

LGTM

Rui Ueyama via Phabricator <reviews at reviews.llvm.org> writes:

> ruiu updated this revision to Diff 92727.
> ruiu added a comment.
>
> - Fix typo.
>
>
> https://reviews.llvm.org/D31255
>
> Files:
>   lld/ELF/InputSection.cpp
>   lld/test/ELF/init-fini-progbits.s
>
>
> Index: lld/test/ELF/init-fini-progbits.s
> ===================================================================
> --- /dev/null
> +++ lld/test/ELF/init-fini-progbits.s
> @@ -0,0 +1,19 @@
> +// REQUIRES: x86
> +
> +// RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
> +// RUN: ld.lld %t -o %t.exe
> +// RUN: llvm-readobj -sections %t.exe | FileCheck %s
> +
> +// CHECK:      Name: .init_array
> +// CHECK-NEXT: Type: SHT_INIT_ARRAY
> +// CHECK:      Name: .fini_array
> +// CHECK-NEXT: Type: SHT_FINI_ARRAY
> +
> +.globl _start
> +_start:
> +  nop
> +
> +.section .init_array.100, "aw", @progbits
> +  .byte 0
> +.section .fini_array.100, "aw", @progbits
> +  .byte 0
> Index: lld/ELF/InputSection.cpp
> ===================================================================
> --- lld/ELF/InputSection.cpp
> +++ lld/ELF/InputSection.cpp
> @@ -71,11 +71,30 @@
>    this->Alignment = V;
>  }
>  
> +// GNU assembler 2.24 and LLVM 4.0.0's MC (the newest release as of
> +// March 2017) fail to infer section types for sections starting with
> +// ".init_array." or ".fini_array.". They set SHT_PROGBITS instead. As a
> +// result, the following assembler directive creates ".init_array.100"
> +// with SHT_PROGBITS, while it should be SHT_INIT_ARRAY, for example.
> +//
> +//   .section .init_array.100, "aw"
> +//
> +// This function forces SHT_{INIT,FINI}_ARRAY so that we can handle
> +// incorrect inputs as if they were correct from the beginning.
> +static uint64_t getType(uint64_t Type, StringRef Name) {
> +  if (Type == SHT_PROGBITS && Name.startswith(".init_array."))
> +    return SHT_INIT_ARRAY;
> +  if (Type == SHT_PROGBITS && Name.startswith(".fini_array."))
> +    return SHT_FINI_ARRAY;
> +  return Type;
> +}
> +
>  template <class ELFT>
>  InputSectionBase::InputSectionBase(elf::ObjectFile<ELFT> *File,
>                                     const typename ELFT::Shdr *Hdr,
>                                     StringRef Name, Kind SectionKind)
> -    : InputSectionBase(File, Hdr->sh_flags & ~SHF_INFO_LINK, Hdr->sh_type,
> +    : InputSectionBase(File, Hdr->sh_flags & ~SHF_INFO_LINK,
> +                       getType(Hdr->sh_type, Name),
>                         Hdr->sh_entsize, Hdr->sh_link, Hdr->sh_info,
>                         Hdr->sh_addralign, getSectionContents(File, Hdr), Name,
>                         SectionKind) {
>
>
> Index: lld/test/ELF/init-fini-progbits.s
> ===================================================================
> --- /dev/null
> +++ lld/test/ELF/init-fini-progbits.s
> @@ -0,0 +1,19 @@
> +// REQUIRES: x86
> +
> +// RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
> +// RUN: ld.lld %t -o %t.exe
> +// RUN: llvm-readobj -sections %t.exe | FileCheck %s
> +
> +// CHECK:      Name: .init_array
> +// CHECK-NEXT: Type: SHT_INIT_ARRAY
> +// CHECK:      Name: .fini_array
> +// CHECK-NEXT: Type: SHT_FINI_ARRAY
> +
> +.globl _start
> +_start:
> +  nop
> +
> +.section .init_array.100, "aw", @progbits
> +  .byte 0
> +.section .fini_array.100, "aw", @progbits
> +  .byte 0
> Index: lld/ELF/InputSection.cpp
> ===================================================================
> --- lld/ELF/InputSection.cpp
> +++ lld/ELF/InputSection.cpp
> @@ -71,11 +71,30 @@
>    this->Alignment = V;
>  }
>  
> +// GNU assembler 2.24 and LLVM 4.0.0's MC (the newest release as of
> +// March 2017) fail to infer section types for sections starting with
> +// ".init_array." or ".fini_array.". They set SHT_PROGBITS instead. As a
> +// result, the following assembler directive creates ".init_array.100"
> +// with SHT_PROGBITS, while it should be SHT_INIT_ARRAY, for example.
> +//
> +//   .section .init_array.100, "aw"
> +//
> +// This function forces SHT_{INIT,FINI}_ARRAY so that we can handle
> +// incorrect inputs as if they were correct from the beginning.
> +static uint64_t getType(uint64_t Type, StringRef Name) {
> +  if (Type == SHT_PROGBITS && Name.startswith(".init_array."))
> +    return SHT_INIT_ARRAY;
> +  if (Type == SHT_PROGBITS && Name.startswith(".fini_array."))
> +    return SHT_FINI_ARRAY;
> +  return Type;
> +}
> +
>  template <class ELFT>
>  InputSectionBase::InputSectionBase(elf::ObjectFile<ELFT> *File,
>                                     const typename ELFT::Shdr *Hdr,
>                                     StringRef Name, Kind SectionKind)
> -    : InputSectionBase(File, Hdr->sh_flags & ~SHF_INFO_LINK, Hdr->sh_type,
> +    : InputSectionBase(File, Hdr->sh_flags & ~SHF_INFO_LINK,
> +                       getType(Hdr->sh_type, Name),
>                         Hdr->sh_entsize, Hdr->sh_link, Hdr->sh_info,
>                         Hdr->sh_addralign, getSectionContents(File, Hdr), Name,
>                         SectionKind) {