Move the support for using .init_array from ARM to the generic
TargetLoweringObjectFileELF. Use this to support it on X86. Unlike ARM,
on X86 it is not easy to find out if .init_array should be used or not, so
the decision is made via TargetOptions and defaults to off.

Add a command line option to llc that enables it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158692 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMTargetObjectFile.cpp b/lib/Target/ARM/ARMTargetObjectFile.cpp
index a5ea1c2..3d85ca7 100644
--- a/lib/Target/ARM/ARMTargetObjectFile.cpp
+++ b/lib/Target/ARM/ARMTargetObjectFile.cpp
@@ -24,20 +24,11 @@
 
 void ARMElfTargetObjectFile::Initialize(MCContext &Ctx,
                                         const TargetMachine &TM) {
+  bool isAAPCS_ABI = TM.getSubtarget<ARMSubtarget>().isAAPCS_ABI();
   TargetLoweringObjectFileELF::Initialize(Ctx, TM);
-  isAAPCS_ABI = TM.getSubtarget<ARMSubtarget>().isAAPCS_ABI();
+  InitializeELF(isAAPCS_ABI);
 
   if (isAAPCS_ABI) {
-    StaticCtorSection =
-      getContext().getELFSection(".init_array", ELF::SHT_INIT_ARRAY,
-                                 ELF::SHF_WRITE |
-                                 ELF::SHF_ALLOC,
-                                 SectionKind::getDataRel());
-    StaticDtorSection =
-      getContext().getELFSection(".fini_array", ELF::SHT_FINI_ARRAY,
-                                 ELF::SHF_WRITE |
-                                 ELF::SHF_ALLOC,
-                                 SectionKind::getDataRel());
     LSDASection = NULL;
   }
 
@@ -47,33 +38,3 @@
                                0,
                                SectionKind::getMetadata());
 }
-
-const MCSection *
-ARMElfTargetObjectFile::getStaticCtorSection(unsigned Priority) const {
-  if (!isAAPCS_ABI)
-    return TargetLoweringObjectFileELF::getStaticCtorSection(Priority);
-
-  if (Priority == 65535)
-    return StaticCtorSection;
-
-  // Emit ctors in priority order.
-  std::string Name = std::string(".init_array.") + utostr(Priority);
-  return getContext().getELFSection(Name, ELF::SHT_INIT_ARRAY,
-                                    ELF::SHF_ALLOC | ELF::SHF_WRITE,
-                                    SectionKind::getDataRel());
-}
-
-const MCSection *
-ARMElfTargetObjectFile::getStaticDtorSection(unsigned Priority) const {
-  if (!isAAPCS_ABI)
-    return TargetLoweringObjectFileELF::getStaticDtorSection(Priority);
-
-  if (Priority == 65535)
-    return StaticDtorSection;
-
-  // Emit dtors in priority order.
-  std::string Name = std::string(".fini_array.") + utostr(Priority);
-  return getContext().getELFSection(Name, ELF::SHT_FINI_ARRAY,
-                                    ELF::SHF_ALLOC | ELF::SHF_WRITE,
-                                    SectionKind::getDataRel());
-}