[Driver] -print-target-triple and -print-effective-triple options

[phosek]

Summary

These can be used to print Clang target and effective triple.

[beanz]

lgtm

cfe/trunk/include/clang/Driver/Options.td

def print_ivar_layout : Flag<["-"], "print-ivar-layout">, Flags<[CC1Option]>,
   HelpText<"Enable Objective-C Ivar layout bitmap print trace">;
 def print_libgcc_file_name : Flag<["-", "--"], "print-libgcc-file-name">,
   HelpText<"Print the library path for the currently used compiler runtime "
            "library (\"libgcc.a\" or \"libclang_rt.builtins.*.a\")">;
 def print_multi_directory : Flag<["-", "--"], "print-multi-directory">;
 def print_multi_lib : Flag<["-", "--"], "print-multi-lib">;
 def print_multi_os_directory : Flag<["-", "--"], "print-multi-os-directory">,
   Flags<[Unsupported]>;
+def print_target_triple : Flag<["-", "--"], "print-target-triple">,
+  HelpText<"Print the normalized target triple">;
+def print_effective_triple : Flag<["-", "--"], "print-effective-triple">,
+  HelpText<"Print the effective target triple">;
 def print_prog_name_EQ : Joined<["-", "--"], "print-prog-name=">,
   HelpText<"Print the full program path of <name>">, MetaVarName<"<name>">;
 def print_resource_dir : Flag<["-", "--"], "print-resource-dir">,
   HelpText<"Print the resource directory pathname">;
 def print_search_dirs : Flag<["-", "--"], "print-search-dirs">,
   HelpText<"Print the paths used for finding libraries and programs">;
 def private__bundle : Flag<["-"], "private_bundle">;
 def pthreads : Flag<["-"], "pthreads">;

cfe/trunk/lib/Driver/Driver.cpp

for (const Multilib &Multilib : TC.getMultilibs()) {
       else {
         StringRef Suffix(Multilib.gccSuffix());
         assert(Suffix.front() == '/');
         llvm::outs() << Suffix.substr(1) << "\n";
       }
     }
     return false;
   }
+
+  if (C.getArgs().hasArg(options::OPT_print_target_triple)) {
+    llvm::outs() << TC.getTripleString() << "\n";
+    return false;
+  }
+
+  if (C.getArgs().hasArg(options::OPT_print_effective_triple)) {
+    const llvm::Triple Triple(TC.ComputeEffectiveClangTriple(C.getArgs()));
+    llvm::outs() << Triple.getTriple() << "\n";
+    return false;
+  }
+
   return true;
 }
 
 // Display an action graph human-readably.  Action A is the "sink" node
 // and latest-occuring action. Traversal is in pre-order, visiting the
 // inputs to each action before printing the action itself.
 static unsigned PrintActions1(const Compilation &C, Action *A,
                               std::map<Action *, unsigned> &Ids) {

cfe/trunk/test/Driver/print-effective-triple.c

+// Test that -print-target-triple prints correct triple.
+
+// RUN: %clang -print-effective-triple 2>&1 \
+// RUN:     --target=thumb-linux-gnu \
+// RUN:   | FileCheck %s
+// CHECK: armv4t-unknown-linux-gnu

cfe/trunk/test/Driver/print-target-triple.c

+// Test that -print-target-triple prints correct triple.
+
+// RUN: %clang -print-target-triple 2>&1 \
+// RUN:     --target=x86_64-linux-gnu \
+// RUN:   | FileCheck %s
+// CHECK: x86_64-unknown-linux-gnu