[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

llvm/lib/Object/ELFObjectFile.cpp

@@ -122,4 +122,69 @@ SubtargetFeatures ELFObjectFileBase::getFeatures() const {
   }
 }
 
+// FIXME Encode from a tablegen description or target parser.
+void ELFObjectFileBase::setARMSubArch(Triple &TheTriple) const {
+  if (TheTriple.getSubArch() != Triple::NoSubArch)
+    return;
+
+  ARMAttributeParser Attributes;
+  std::error_code EC = getBuildAttributes(Attributes);
+  if (EC)
+    return;
+
+  std::string Triple;
+  // Default to ARM, but use the triple if it's been set.
+  if (TheTriple.getArch() == Triple::thumb ||
+      TheTriple.getArch() == Triple::thumbeb)
+    Triple = "thumb";
+  else
+    Triple = "arm";
+
+  switch(Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch)) {
+  case ARMBuildAttrs::v4:
+    Triple += "v4";
+    break;
+  case ARMBuildAttrs::v4T:
+    Triple += "v4t";
+    break;
+  case ARMBuildAttrs::v5T:
+    Triple += "v5t";
+    break;
+  case ARMBuildAttrs::v5TE:
+    Triple += "v5te";
+    break;
+  case ARMBuildAttrs::v5TEJ:
+    Triple += "v5tej";
+    break;
+  case ARMBuildAttrs::v6:
+    Triple += "v6";
+    break;
+  case ARMBuildAttrs::v6KZ:
+    Triple += "v6kz";
+    break;
+  case ARMBuildAttrs::v6T2:
+    Triple += "v6t2";
+    break;
+  case ARMBuildAttrs::v6K:
+    Triple += "v6k";
+    break;
+  case ARMBuildAttrs::v7:
+    Triple += "v7";
+    break;
+  case ARMBuildAttrs::v6_M:
+    Triple += "v6m";
+    break;
+  case ARMBuildAttrs::v6S_M:
+    Triple += "v6sm";
+    break;
+  case ARMBuildAttrs::v7E_M:
+    Triple += "v7em";
+    break;
+  }
+  if (!isLittleEndian())
+    Triple += "eb";
+
+  TheTriple.setArchName(Triple);
+}
+
 } // end namespace llvm