Fix error reporting in the PNaCl bitcode reader.

tools/llvm-nm/llvm-nm.cpp

 //===-- llvm-nm.cpp - Symbol table dumping utility for llvm ---------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This program is a utility that works like traditional Unix "nm", that is, it
@@ skipping 148 matching lines @@
 
 std::string ToolName;
 
 // @LOCALMOD-BEGIN
 cl::opt<NaClFileFormat> InputFileFormat(
     "bitcode-format", cl::desc("Define format of input file:"),
     cl::values(clEnumValN(LLVMFormat, "llvm", "LLVM file (default)"),
                clEnumValN(PNaClFormat, "pnacl", "PNaCl bitcode file"),
                clEnumValEnd),
     cl::init(LLVMFormat));
+
+static cl::opt<bool>
+VerboseErrors(
+    "verbose-parse-errors",
+    cl::desc("Print out more descriptive PNaCl bitcode parse errors"),
+    cl::init(false));
 // @LOCALMOD-END
 }
 
 static void error(Twine Message, Twine Path = Twine()) {
   HadError = true;
   errs() << ToolName << ": " << Path << ": " << Message << ".\n";
 }
 
 static bool error(std::error_code EC, Twine Path = Twine()) {
   if (EC) {
@@ skipping 825 matching lines @@
       MemoryBuffer::getFileOrSTDIN(Filename);
   if (error(BufferOrErr.getError(), Filename))
     return;
 
   LLVMContext &Context = getGlobalContext();
 
   // @LOCALMOD-BEGIN
   // Support parsing PNaCl bitcode files
   /* TODO(jfb) This is currently broken: the code base now requires an Object.
   if (InputFileFormat == PNaClFormat) {
-    std::string ErrorMessage;
-    Module *Result = NaClParseBitcodeFile(BufferOrErr.get().release(), Context,
-                                          &ErrorMessage);
+    std::string VerboseBuffer;
+    raw_string_ostream VerboseStrm(VerboseBuffer);
+    raw_ostream *Verbose = VerboseErrors ? &VerboseStrm : nullptr;
+    ErrorOr<Module *> Result =
+        NaClParseBitcodeFile(BufferOrErr.get().release(), Verbose,
+        Context);
     if (Result) {
-      DumpSymbolNamesFromModule(Result);
+      DumpSymbolNamesFromModule(Result.get());
       delete Result;
     } else {
-      error(ErrorMessage, Filename);
+      error(VerboseStrm.str() + Result.message()), Filename);
       return;
     }
   }
   */
   // @LOCALMOD-END
 
   ErrorOr<Binary *> BinaryOrErr =
       createBinary(std::move(*BufferOrErr), &Context);
   if (error(BinaryOrErr.getError(), Filename))
     return;
@@ skipping 233 matching lines @@
           "for the -s option");
 
   std::for_each(InputFilenames.begin(), InputFilenames.end(),
                 dumpSymbolNamesFromFile);
 
   if (HadError)
     return 1;
 
   return 0;
 }