Use getArch instead of getArchName.

The darwin change should be a nop since Triple::getArchTypeForDarwinArchName
doesn't know about amd64.

If things like amd64-mingw32 are to be rejected, we should print a error
earlier on instead of silently using the wrong abi.

Remove old comment that looks out of place, this is "in clang".

llvm-svn: 165368
diff --git a/clang/lib/Driver/ToolChains.cpp b/clang/lib/Driver/ToolChains.cpp
index 27375de..54f8c42 100644
--- a/clang/lib/Driver/ToolChains.cpp
+++ b/clang/lib/Driver/ToolChains.cpp
@@ -955,9 +955,7 @@
 }
 
 bool Darwin::IsUnwindTablesDefault() const {
-  // FIXME: Gross; we should probably have some separate target
-  // definition, possibly even reusing the one in clang.
-  return getArchName() == "x86_64";
+  return getArch() == llvm::Triple::x86_64;
 }
 
 bool Darwin::UseDwarfDebugFlags() const {
@@ -1457,8 +1455,6 @@
 }
 
 bool Generic_GCC::IsUnwindTablesDefault() const {
-  // FIXME: Gross; we should probably have some separate target
-  // definition, possibly even reusing the one in clang.
   return getArch() == llvm::Triple::x86_64;
 }