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.

llvm-svn: 158692

1 files changed, 40 insertions, 8 deletions

diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 7a89e3ca630..6842eec4864 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -349,10 +349,17 @@ TargetLoweringObjectFileELF::getStaticCtorSection(unsigned Priority) const {
   if (Priority == 65535)
     return StaticCtorSection;
 
-  std::string Name = std::string(".ctors.") + utostr(65535 - Priority);
-  return getContext().getELFSection(Name, ELF::SHT_PROGBITS,
-                                    ELF::SHF_ALLOC |ELF::SHF_WRITE,
-                                    SectionKind::getDataRel());
+  if (UseInitArray) {
+    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());
+  } else {
+    std::string Name = std::string(".ctors.") + utostr(65535 - Priority);
+    return getContext().getELFSection(Name, ELF::SHT_PROGBITS,
+                                      ELF::SHF_ALLOC |ELF::SHF_WRITE,
+                                      SectionKind::getDataRel());
+  }
 }
 
 const MCSection *
@@ -362,10 +369,35 @@ TargetLoweringObjectFileELF::getStaticDtorSection(unsigned Priority) const {
   if (Priority == 65535)
     return StaticDtorSection;
 
-  std::string Name = std::string(".dtors.") + utostr(65535 - Priority);
-  return getContext().getELFSection(Name, ELF::SHT_PROGBITS,
-                                    ELF::SHF_ALLOC |ELF::SHF_WRITE,
-                                    SectionKind::getDataRel());
+  if (UseInitArray) {
+    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());
+  } else {
+    std::string Name = std::string(".dtors.") + utostr(65535 - Priority);
+    return getContext().getELFSection(Name, ELF::SHT_PROGBITS,
+                                      ELF::SHF_ALLOC |ELF::SHF_WRITE,
+                                      SectionKind::getDataRel());
+  }
+}
+
+void
+TargetLoweringObjectFileELF::InitializeELF(bool UseInitArray_) {
+  UseInitArray = UseInitArray_;
+  if (!UseInitArray)
+    return;
+
+  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());
 }
 
 //===----------------------------------------------------------------------===//