Support -color-diagnostics={auto,always,never}.

-color-diagnostics=auto is default because that's the same as
Clang's default. When color is enabled, error or warning messages
are colored like this.

  error:
  <bold>ld.lld</bold> <red>error:</red> foo.o: no such file

  warning:
  <bold>ld.lld</bold> <magenta>warning:</magenta> foo.o: no such file

Differential Revision: https://reviews.llvm.org/D27117

llvm-svn: 287949

1 files changed, 30 insertions, 4 deletions

diff --git a/lld/ELF/Error.cpp b/lld/ELF/Error.cpp
index a230bf6dadd..2b5cfe9bc70 100644
--- a/lld/ELF/Error.cpp
+++ b/lld/ELF/Error.cpp
@@ -13,6 +13,7 @@
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/Process.h"
 #include "llvm/Support/raw_ostream.h"
 #include <mutex>
 
@@ -20,6 +21,7 @@
 #include <unistd.h>
 #endif
 
+using namespace lld::elf;
 using namespace llvm;
 
 namespace lld {
@@ -32,6 +34,26 @@ StringRef elf::Argv0;
 // but outs() or errs() are not thread-safe. We protect them using a mutex.
 static std::mutex Mu;
 
+static bool useColor() {
+  if (Config->ColorDiagnostics == ColorPolicy::Always)
+    return true;
+  if (Config->ColorDiagnostics == ColorPolicy::Never)
+    return false;
+  return ErrorOS == &errs() && sys::Process::StandardErrHasColors();
+}
+
+static void print(StringRef S, raw_ostream::Colors C) {
+  if (useColor()) {
+    ErrorOS->changeColor(raw_ostream::WHITE, /*Bold=*/true);
+    *ErrorOS << Argv0 + ": ";
+    ErrorOS->changeColor(C, true);
+    *ErrorOS << S;
+    ErrorOS->resetColor();
+  } else {
+    *ErrorOS << Argv0 + ": " << S;
+  }
+}
+
 void elf::log(const Twine &Msg) {
   std::lock_guard<std::mutex> Lock(Mu);
   if (Config->Verbose)
@@ -44,16 +66,19 @@ void elf::warn(const Twine &Msg) {
     return;
   }
   std::lock_guard<std::mutex> Lock(Mu);
-  *ErrorOS << Argv0 << ": warning: " << Msg << "\n";
+  print("warning: ", raw_ostream::MAGENTA);
+  *ErrorOS << Msg << "\n";
 }
 
 void elf::error(const Twine &Msg) {
   std::lock_guard<std::mutex> Lock(Mu);
 
   if (Config->ErrorLimit == 0 || ErrorCount < Config->ErrorLimit) {
-    *ErrorOS << Argv0 << ": error: " << Msg << "\n";
+    print("error: ", raw_ostream::RED);
+    *ErrorOS << Msg << "\n";
   } else if (ErrorCount == Config->ErrorLimit) {
-    *ErrorOS << Argv0 << ": error: too many errors emitted, stopping now"
+    print("error: ", raw_ostream::RED);
+    *ErrorOS << "too many errors emitted, stopping now"
              << " (use -error-limit=0 to see all errors)\n";
     if (Config->ExitEarly)
       exitLld(1);
@@ -79,7 +104,8 @@ void elf::exitLld(int Val) {
 
 void elf::fatal(const Twine &Msg) {
   std::lock_guard<std::mutex> Lock(Mu);
-  *ErrorOS << Argv0 << ": error: " << Msg << "\n";
+  print("error: ", raw_ostream::RED);
+  *ErrorOS << Msg << "\n";
   exitLld(1);
 }