[lld] r298569 - Force @{init, fini}_array if section name starts with ".{init, fini}_array.".

[Rui Ueyama via llvm-commits]

Author: ruiu
Date: Wed Mar 22 20:00:41 2017
New Revision: 298569

URL: http://llvm.org/viewvc/llvm-project?rev=298569&view=rev
Log:
Force @{init,fini}_array if section name starts with ".{init,fini}_array.".

Fixes https://bugs.llvm.org/show_bug.cgi?id=32307.

Differential Revision: https://reviews.llvm.org/D31255

Added:
    lld/trunk/test/ELF/init-fini-progbits.s
Modified:
    lld/trunk/ELF/InputSection.cpp

Modified: lld/trunk/ELF/InputSection.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSection.cpp?rev=298569&r1=298568&r2=298569&view=diff
==============================================================================
--- lld/trunk/ELF/InputSection.cpp (original)
+++ lld/trunk/ELF/InputSection.cpp Wed Mar 22 20:00:41 2017
@@ -71,14 +71,32 @@ InputSectionBase::InputSectionBase(Input
   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 of
+// SHF_INIT_ARRAY. As a result, the following assembler directive
+// creates ".init_array.100" with SHT_PROGBITS, 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,
-                       Hdr->sh_entsize, Hdr->sh_link, Hdr->sh_info,
-                       Hdr->sh_addralign, getSectionContents(File, Hdr), Name,
-                       SectionKind) {
+    : 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) {
   // We reject object files having insanely large alignments even though
   // they are allowed by the spec. I think 4GB is a reasonable limitation.
   // We might want to relax this in the future.

Added: lld/trunk/test/ELF/init-fini-progbits.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/init-fini-progbits.s?rev=298569&view=auto
==============================================================================
--- lld/trunk/test/ELF/init-fini-progbits.s (added)
+++ lld/trunk/test/ELF/init-fini-progbits.s Wed Mar 22 20:00:41 2017
@@ -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