Driver: Lookup program names using llvm::sys::Program::FindProgramByName

if our usual methods fail. This isn't necessary for running the tool,
but improves the accuracy of logging output.

Also, have GCC tools lookup gcc program path.

llvm-svn: 67243

clang/lib/Driver/Driver.cpp

@@ -26,6 +26,7 @@
 #include "llvm/Support/PrettyStackTrace.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/System/Path.h"
+#include "llvm/System/Program.h"
 
 #include "InputInfo.h"
 
@@ -879,6 +880,11 @@ llvm::sys::Path Driver::GetProgramPath(const char *Name,
   if (P.exists())
     return P;
 
+  // Search path to increase accuracy of logging output.
+  P = llvm::sys::Program::FindProgramByName(Name);
+  if (!P.empty())
+    return P;
+
   return llvm::sys::Path(Name);
 }
 

clang/lib/Driver/Tools.cpp

@@ -392,7 +392,9 @@ void gcc::Common::ConstructJob(Compilation &C, const JobAction &JA,
       CmdArgs.push_back(II.getInputFilename());
   }
 
-  Dest.addCommand(new Command("gcc", CmdArgs));
+  const char *Exec = 
+    Args.MakeArgString(getToolChain().GetProgramPath(C, "gcc").c_str());
+  Dest.addCommand(new Command(Exec, CmdArgs));
 }
 
 void gcc::Preprocess::RenderExtraToolArgs(ArgStringList &CmdArgs) const {