[ARM] Enable objdump to construct triple for ARM

Now that The ARMAttributeParser has been moved into the library,
it has been modified so that it can parse the attributes without
printing them and stores them in a map. ELFObjectFile now queries
the attributes to fill out the architecture details of a provided
triple for 'arm' and 'thumb' targets. llvm-objdump uses this new
functionality.

Differential Revision: https://reviews.llvm.org/D28281

llvm-svn: 291898

1 files changed, 19 insertions, 2 deletions

diff --git a/llvm/tools/llvm-objdump/llvm-objdump.cpp b/llvm/tools/llvm-objdump/llvm-objdump.cpp
index 8373f0ce3f1..6b8a43ea1bd 100644
--- a/llvm/tools/llvm-objdump/llvm-objdump.cpp
+++ b/llvm/tools/llvm-objdump/llvm-objdump.cpp
@@ -357,7 +357,16 @@ static const Target *getTarget(const ObjectFile *Obj = nullptr) {
   llvm::Triple TheTriple("unknown-unknown-unknown");
   if (TripleName.empty()) {
     if (Obj) {
-      TheTriple.setArch(Triple::ArchType(Obj->getArch()));
+      auto Arch = Obj->getArch();
+      TheTriple.setArch(Triple::ArchType(Arch));
+
+      // For ARM targets, try to use the build attributes to build determine
+      // the build target. Target features are also added, but later during
+      // disassembly.
+      if (Arch == Triple::arm || Arch == Triple::armeb) {
+        Obj->setARMSubArch(TheTriple);
+      }
+
       // TheTriple defaults to ELF, and COFF doesn't have an environment:
       // the best we can do here is indicate that it is mach-o.
       if (Obj->isMachO())
@@ -369,8 +378,16 @@ static const Target *getTarget(const ObjectFile *Obj = nullptr) {
           TheTriple.setTriple("thumbv7-windows");
       }
     }
-  } else
+  } else {
     TheTriple.setTriple(Triple::normalize(TripleName));
+    // Use the triple, but also try to combine with ARM build attributes.
+    if (Obj) {
+      auto Arch = Obj->getArch();
+      if (Arch == Triple::arm || Arch == Triple::armeb) {
+        Obj->setARMSubArch(TheTriple);
+      }
+    }
+  }
 
   // Get the target specific parser.
   std::string Error;