[dsymutil] Unify error handling and add color

[JDevlieghere]

Summary

We improved the handling of errors and warnings in dwarfdump's verifier in
rL314498. This patch does the same thing for dsymutil.

I moved the SyntaxHighlighting header out of libDwarf. I'm not sure
whether it would make sense to move this in support, as the syntax
itself is still pretty much tailored to dumping debug info. Putting it
in the DebugInfo root also didn't feel right, so this felt like the
least invasive thing to do for now. Please don't hesitate to let me know
if you have a better alternative in mind!

[aprantl]

We might want to think about separating WithColor from the actual syntax definition. Then we could move WithColor to Support, and perhaps have a DWARF syntax definition in a header only in libDebugInfo. Maybe it doesn't matter if it is in support, too, since we already have all the DWARF constants there.

In any case, this seems to be an incremental improvement over the status quo, so it works for me, too.

[JDevlieghere]

Thanks! I might as well do the move to Support first, rather than moving the file around twice.

llvm/trunk/test/tools/dsymutil/X86/module-warnings.test

 # CHECK-NOT: static libraries
 #
 # RUN: rm -rf %t.dir/ModuleCache
 # RUN: llvm-dsymutil -f -oso-prepend-path=%t.dir -y %s -o %t 2>&1 \
 # RUN:   | FileCheck %s --check-prefix=STATIC
 # STATIC: warning: {{.*}}Bar.pcm:
 # STATIC: note: Linking a static library
 # STATIC: warning: {{.*}}Foo.pcm:
-# STATIC-NOT: note:
+# STATIC-NOT: warning:
 
 ---
 triple:          'x86_64-apple-darwin'
 objects:
   - filename: libstatic.a(1.o)
     symbols:
       - { sym: __Z3foov, objAddr: 0x0, binAddr: 0x10000, size: 0x10 }
 ...

llvm/trunk/test/tools/dsymutil/X86/swift-ast-x86_64.test

 DSYMUTIL: filename:{{.*}}swift-ast.swiftmodule
 DSYMUTIL: DEBUG MAP OBJECT:{{.*}}swift-ast.swiftmodule
 
 READOBJ: Name:{{.*}}__swift_ast
 READOBJ: |SWIFTMODULE DATA|
 READOBJ-NEXT: |.|
 
 RUN: llvm-dsymutil -oso-prepend-path %p/.. %p/../Inputs/swift-ast.macho.x86_64 -no-output -verbose 2>&1 | FileCheck %s --check-prefix=TIMESTAMP
-TIMESTAMP: Warning: Timestamp mismatch
+TIMESTAMP: warning: Timestamp mismatch

llvm/trunk/tools/dsymutil/DwarfLinker.cpp

 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/LEB128.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/ToolOutputFile.h"
+#include "llvm/Support/WithColor.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
 #include <algorithm>
 #include <cassert>
 #include <cinttypes>
 #include <climits>
 #include <cstdint>
static bool inFunctionScope(CompileUnit &U, unsigned Idx) {
   while (Idx) {
     if (U.getOrigUnit().getDIEAtIndex(Idx).getTag() == dwarf::DW_TAG_subprogram)
       return true;
     Idx = U.getInfo(Idx).ParentIdx;
   }
   return false;
 }
 
+static raw_ostream &error_ostream() {
+  return WithColor(errs(), HighlightColor::Error).get() << "error: ";
+}
+
+static raw_ostream &warn_ostream() {
+  return WithColor(errs(), HighlightColor::Warning).get() << "warning: ";
+}
+
+static raw_ostream &note_ostream() {
+  return WithColor(errs(), HighlightColor::Note).get() << "note: ";
+}
 } // end anonymous namespace
 
+void warn(Twine Warning, Twine Context) {
+  warn_ostream() << Warning + "\n";
+  if (!Context.isTriviallyEmpty())
+    note_ostream() << Twine("while processing ") + Context + ":\n";
+}
+
+bool error(Twine Error, Twine Context) {
+  error_ostream() << Error + "\n";
+  if (!Context.isTriviallyEmpty())
+    note_ostream() << Twine("while processing ") + Context + ":\n";
+  return false;
+}
+
 void CompileUnit::markEverythingAsKept() {
   unsigned Idx = 0;
 
   setHasInterestingContent();
 
   for (auto &I : Info) {
     // Mark everything that wasn't explicit marked for pruning.
     I.Keep = !I.Prune;
void DwarfLinker::reportWarning(const Twine &Warning,
 
   if (!Options.Verbose || !DIE)
     return;
 
   DIDumpOptions DumpOpts;
   DumpOpts.RecurseDepth = 0;
   DumpOpts.Verbose = Options.Verbose;
 
-  errs() << "    in DIE:\n";
+  note_ostream() << "    in DIE:\n";
   DIE->dump(errs(), 6 /* Indent */, DumpOpts);
 }
 
 bool DwarfLinker::createStreamer(const Triple &TheTriple,
                                  raw_fd_ostream &OutFile) {
   if (Options.NoOutput)
     return true;
 
if (!ErrOrObj) {
     bool isArchive = ObjFile.endswith(")");
     if (isClangModule) {
       StringRef ModuleCacheDir = sys::path::parent_path(Path);
       if (sys::fs::exists(ModuleCacheDir)) {
         // If the module's parent directory exists, we assume that the module
         // cache has expired and was pruned by clang.  A more adventurous
         // dsymutil would invoke clang to rebuild the module now.
         if (!ModuleCacheHintDisplayed) {
-          errs() << "note: The clang module cache may have expired since this "
-                    "object file was built. Rebuilding the object file will "
-                    "rebuild the module cache.\n";
+          note_ostream() << "The clang module cache may have expired since "
+                            "this object file was built. Rebuilding the "
+                            "object file will rebuild the module cache.\n";
           ModuleCacheHintDisplayed = true;
         }
       } else if (isArchive) {
         // If the module cache directory doesn't exist at all and the object
         // file is inside a static library, we assume that the static library
         // was built on a different machine. We don't want to discourage module
         // debugging for convenience libraries within a project though.
         if (!ArchiveHintDisplayed) {
-          errs() << "note: Linking a static library that was built with "
+          note_ostream() << "Linking a static library that was built with "
                             "-gmodules, but the module cache was not found.  "
-                    "Redistributable static libraries should never be built "
-                    "with module debugging enabled.  The debug experience will "
-                    "be degraded due to incomplete debug information.\n";
+                            "Redistributable static libraries should never be "
+                            "built with module debugging enabled.  The debug "
+                            "experience will be degraded due to incomplete "
+                            "debug information.\n";
           ArchiveHintDisplayed = true;
         }
       }
     }
     return Error::success();
   }
 
   std::unique_ptr<CompileUnit> Unit;
 
   // Setup access to the debug info.
   auto DwarfContext = DWARFContext::create(*ErrOrObj);
   RelocationManager RelocMgr(*this);
   for (const auto &CU : DwarfContext->compile_units()) {
     maybeUpdateMaxDwarfVersion(CU->getVersion());
 
     // Recursively get all modules imported by this one.
     auto CUDie = CU->getUnitDIE(false);
     if (!registerModuleReference(CUDie, *CU, ModuleMap, Indent)) {
       if (Unit) {
         std::string Err =
             (Filename +
              ": Clang modules are expected to have exactly 1 compile unit.\n")
                 .str();
-        errs() << Err;
+        error(Err);
         return make_error<StringError>(Err, inconvertibleErrorCode());
       }
       // FIXME: Until PR27449 (https://llvm.org/bugs/show_bug.cgi?id=27449) is
       // fixed in clang, only warn about DWO_id mismatches in verbose mode.
       // ASTFileSignatures will change randomly when a module is rebuilt.
       uint64_t PCMDwoId = getDwoId(CUDie, *CU);
       if (PCMDwoId != DwoId) {
         if (Options.Verbose)
for (const auto &Obj : Map.objects()) {
     if (Obj->getType() == MachO::N_AST) {
       StringRef File = Obj->getObjectFilename();
       auto ErrorOrMem = MemoryBuffer::getFile(File);
       if (!ErrorOrMem) {
         errs() << "Warning: Could not open " << File << "\n";
         continue;
       }
       sys::fs::file_status Stat;
-      if (auto errc = sys::fs::status(File, Stat)) {
-        errs() << "Warning: " << errc.message() << "\n";
+      if (auto Err = sys::fs::status(File, Stat)) {
+        warn(Err.message());
         continue;
       }
       if (!Options.NoTimestamp && Stat.getLastModificationTime() !=
                                       sys::TimePoint<>(Obj->getTimestamp())) {
-        errs() << "Warning: Timestamp mismatch for " << File << ": "
+        // Not using the helper here as we can easily stream TimePoint<>.
+        warn_ostream() << "Timestamp mismatch for " << File << ": "
                        << Stat.getLastModificationTime() << " and "
                        << sys::TimePoint<>(Obj->getTimestamp()) << "\n";
         continue;
       }
 
       // Copy the module into the .swift_ast section.
       if (!Options.NoOutput)
         Streamer->emitSwiftAST((*ErrorOrMem)->getBuffer());
       continue;
     }

llvm/trunk/tools/dsymutil/dsymutil.h

 bool dumpStab(StringRef InputFile, ArrayRef<std::string> Archs,
               StringRef PrependPath = "");
 
 /// Link the Dwarf debug info as directed by the passed DebugMap \p DM into a
 /// DwarfFile named \p OutputFilename. \returns false if the link failed.
 bool linkDwarf(raw_fd_ostream &OutFile, const DebugMap &DM,
                const LinkOptions &Options);
 
-void warn(const Twine &Warning, const Twine &Context);
-bool error(const Twine &Error, const Twine &Context);
+void warn(Twine Warning, Twine Context = {});
+bool error(Twine Error, Twine Context = {});
 
 } // end namespace dsymutil
 } // end namespace llvm
 
 #endif // LLVM_TOOLS_DSYMUTIL_DSYMUTIL_H