[dsymutil] Embed toolchain in dSYM bundle

[JDevlieghere]

Summary

Allow us to embed the (Xcode) toolchain in the dSYM bundle's property
list.

llvm/trunk/docs/CommandGuide/dsymutil.rst

 .. option:: --oso-prepend-path=<path>
 
  Specifies a ``path`` to prepend to all debug symbol object file paths.
 
 .. option:: -s, --symtab
 
  Dumps the symbol table found in *executable* or object file(s) and exits.
 
+.. option:: --toolchain
+
+ Embed the toolchain in the dSYM bundle's property list.
+
 .. option:: -u, --update
 
  Update an existing dSYM file to contain the latest accelerator tables and
  other DWARF optimizations. This option will rebuild the '.apple_names' and
  '.apple_types' hashed accelerator tables.
 
 .. option:: -v, --verbose
 

llvm/trunk/test/tools/dsymutil/X86/darwin-bundle.test

 REQUIRES: system-darwin
 
 RUN: rm -rf %t
 RUN: mkdir -p %t/dsymdest
 RUN: cat %p/../Inputs/basic.macho.x86_64 > %t/basic.macho.x86_64
 RUN: cat %p/../Inputs/Info.plist > %t/Info.plist
 
 RUN: llvm-dsymutil -oso-prepend-path=%p/.. %t/basic.macho.x86_64 -o %t/dsymdest/basic.macho.x86_64.dSYM
 RUN: FileCheck %s --input-file %t/dsymdest/basic.macho.x86_64.dSYM/Contents/Info.plist
 
+RUN: llvm-dsymutil -oso-prepend-path=%p/.. %t/basic.macho.x86_64 -toolchain "toolchain" -o %t/dsymdest/basic.macho.x86_64.dSYM
+RUN: FileCheck %s --input-file %t/dsymdest/basic.macho.x86_64.dSYM/Contents/Info.plist --check-prefix=CHECK --check-prefix=TOOLCHAIN
+
 CHECK: <?xml version="1.0" encoding="UTF-8"?>
 CHECK-NEXT: <!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 CHECK-NEXT: <plist version="1.0">
 CHECK-NEXT:         <dict>
 CHECK-NEXT:                 <key>CFBundleDevelopmentRegion</key>
 CHECK-NEXT:                 <string>English</string>
 CHECK-NEXT:                 <key>CFBundleIdentifier</key>
 CHECK-NEXT:                 <string>com.apple.xcode.dsym.custom</string>
 CHECK-NEXT:                 <key>CFBundleInfoDictionaryVersion</key>
 CHECK-NEXT:                 <string>6.0</string>
 CHECK-NEXT:                 <key>CFBundlePackageType</key>
 CHECK-NEXT:                 <string>dSYM</string>
 CHECK-NEXT:                 <key>CFBundleSignature</key>
 CHECK-NEXT:                 <string>????</string>
 CHECK-NEXT:                 <key>CFBundleShortVersionString</key>
 CHECK-NEXT:                 <string>2.0</string>
 CHECK-NEXT:                 <key>CFBundleVersion</key>
 CHECK-NEXT:                 <string>2</string>
-CHECK-NEXT:         </dict>
+TOOLCHAIN:                  <key>Toolchain</key>
+TOOLCHAIN-NEXT:             <string>toolchain</string>
+CHECK:              </dict>
 CHECK-NEXT: </plist>

llvm/trunk/test/tools/dsymutil/cmdline.test

 RUN: llvm-dsymutil -help 2>&1 | FileCheck --check-prefix=HELP %s
 HELP: OVERVIEW: manipulate archived DWARF debug symbol files.
 HELP: USAGE: llvm-dsymutil{{[^ ]*}} [options] <input files>
 HELP-NOT: -reverse-iterate
 HELP: Specific Options:
 HELP: -arch=<arch>
 HELP: -dump-debug-map
 HELP: -flat
 HELP: -minimize
 HELP: -no-odr
 HELP: -no-output
 HELP: -no-swiftmodule-timestamp
 HELP: -num-threads=<n>
 HELP: -o=<filename>
 HELP: -oso-prepend-path=<path>
 HELP: -symtab
+HELP: -toolchain
 HELP: -update
 HELP: -verbose
 HELP: -verify
 HELP: -y
 HELP-NOT: -reverse-iterate
 
 RUN: llvm-dsymutil --version 2>&1 | FileCheck --check-prefix=VERSION %s
 VERSION: {{ version }}

llvm/trunk/tools/dsymutil/dsymutil.cpp

 
 static opt<bool> InputIsYAMLDebugMap(
     "y", desc("Treat the input file is a YAML debug map rather than a binary."),
     init(false), cat(DsymCategory));
 
 static opt<bool> Verify("verify", desc("Verify the linked DWARF debug info."),
                         cat(DsymCategory));
 
+static opt<std::string>
+    Toolchain("toolchain", desc("Embed toolchain information in dSYM bundle."),
+              cat(DsymCategory));
+
 static bool createPlistFile(llvm::StringRef Bin, llvm::StringRef BundleRoot) {
   if (NoOutput)
     return true;
 
   // Create plist file to write to.
   llvm::SmallString<128> InfoPlist(BundleRoot);
   llvm::sys::path::append(InfoPlist, "Contents/Info.plist");
   std::error_code EC;
PL << "<?xml version=\"1.0\" encoding=\"UTF-8\"\?>\n"
      << "\t\t<key>CFBundleSignature</key>\n"
      << "\t\t<string>\?\?\?\?</string>\n";
 
   if (!BI.OmitShortVersion())
     PL << "\t\t<key>CFBundleShortVersionString</key>\n"
        << "\t\t<string>" << BI.ShortVersionStr << "</string>\n";
 
   PL << "\t\t<key>CFBundleVersion</key>\n"
-     << "\t\t<string>" << BI.VersionStr << "</string>\n"
-     << "\t</dict>\n"
+     << "\t\t<string>" << BI.VersionStr << "</string>\n";
+
+  if (!Toolchain.empty())
+    PL << "\t\t<key>Toolchain</key>\n"
+       << "\t\t<string>" << Toolchain << "</string>\n";
+
+  PL << "\t</dict>\n"
      << "</plist>\n";
 
   PL.close();
   return true;
 }
 
 static bool createBundleDir(llvm::StringRef BundleBase) {
   if (NoOutput)