[llvm-objdump] Support detection of feature bits from the object and implement this for Mips.

Summary:
The Mips implementation only covers the feature bits described by the ELF
e_flags so far. Mips stores additional feature bits such as MSA in the
.MIPS.abiflags section.

Also fixed a small bug this revealed where microMIPS wouldn't add the
EF_MIPS_MICROMIPS flag when using -filetype=obj.

Reviewers: echristo, rafael

Subscribers: rafael, mehdi_amini, dsanders, sdardis, llvm-commits

Differential Revision: http://reviews.llvm.org/D21125

llvm-svn: 272880

1 files changed, 2 insertions, 4 deletions

diff --git a/llvm/tools/llvm-objdump/llvm-objdump.cpp b/llvm/tools/llvm-objdump/llvm-objdump.cpp
index 38550b91530..3beb01ad6eb 100644
--- a/llvm/tools/llvm-objdump/llvm-objdump.cpp
+++ b/llvm/tools/llvm-objdump/llvm-objdump.cpp
@@ -931,12 +931,10 @@ static void DisassembleObject(const ObjectFile *Obj, bool InlineRelocs) {
   const Target *TheTarget = getTarget(Obj);
 
   // Package up features to be passed to target/subtarget
-  std::string FeaturesStr;
+  SubtargetFeatures Features = Obj->getFeatures();
   if (MAttrs.size()) {
-    SubtargetFeatures Features;
     for (unsigned i = 0; i != MAttrs.size(); ++i)
       Features.AddFeature(MAttrs[i]);
-    FeaturesStr = Features.getString();
   }
 
   std::unique_ptr<const MCRegisterInfo> MRI(
@@ -950,7 +948,7 @@ static void DisassembleObject(const ObjectFile *Obj, bool InlineRelocs) {
   if (!AsmInfo)
     report_fatal_error("error: no assembly info for target " + TripleName);
   std::unique_ptr<const MCSubtargetInfo> STI(
-      TheTarget->createMCSubtargetInfo(TripleName, MCPU, FeaturesStr));
+      TheTarget->createMCSubtargetInfo(TripleName, MCPU, Features.getString()));
   if (!STI)
     report_fatal_error("error: no subtarget info for target " + TripleName);
   std::unique_ptr<const MCInstrInfo> MII(TheTarget->createMCInstrInfo());