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Mark ELF sections whose name start with .note as note 

Previously, such section would be marked as SHT_PROGBITS which
makes it impossible to use an initialized C variable declaration
to emit an (allocated) ELF note. The new behavior is also consistent
with ELF assembly parser.

Differential Revision: https://reviews.llvm.org/D24692

llvm-svn: 282010
This commit is contained in:
Petr Hosek 2016-09-20 20:21:13 +00:00
parent c7368287b7
commit 1290355f5a
2 changed files with 24 additions and 0 deletions
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5
llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
View File

@ -151,6 +151,11 @@ getELFKindForNamedSection(StringRef Name, SectionKind K) {
static unsigned getELFSectionType(StringRef Name, SectionKind K) {
// Use SHT_NOTE for section whose name starts with ".note" to allow
// emitting ELF notes from C variable declaration.
// See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77609
if (Name.startswith(".note"))
return ELF::SHT_NOTE;
if (Name == ".init_array")
return ELF::SHT_INIT_ARRAY;

19
llvm/test/CodeGen/X86/note-sections.ll Normal file
View File

@ -0,0 +1,19 @@
; RUN: llc -mtriple x86_64-pc-linux < %s | FileCheck %s
%struct.note = type { %struct.Elf32_Nhdr, [7 x i8], %struct.payload }
%struct.Elf32_Nhdr = type { i32, i32, i32 }
%struct.payload = type { i16 }
@foonote = internal constant %struct.note { %struct.Elf32_Nhdr { i32 7, i32 2, i32 17 }, [7 x i8] c"foobar\00", %struct.payload { i16 23 } }, section ".note.foo", align 4
; CHECK: .section .note.foo,"a",@note
; CHECK-NEXT: .p2align 2
; CHECK-NEXT: foonote:
; CHECK-NEXT: .long 7
; CHECK-NEXT: .long 2
; CHECK-NEXT: .long 17
; CHECK-NEXT: .asciz "foobar"
; CHECK-NEXT: .zero 1
; CHECK-NEXT: .short 23
; CHECK-NEXT: .zero 2
; CHECK-NEXT: .size foonote, 24