[clang] [clang][Diagnostics] Highlight code snippets (PR #66514)

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In-Reply-To: <llvm/llvm-project/pull/66514/clang at github.com>


================
@@ -1276,22 +1280,49 @@ void TextDiagnostic::emitSnippetAndCaret(
 }
 
 void TextDiagnostic::emitSnippet(StringRef SourceLine,
-                                 unsigned MaxLineNoDisplayWidth,
-                                 unsigned LineNo) {
+                                 unsigned MaxLineNoDisplayWidth, FileID FID,
+                                 const SourceManager &SM, unsigned LineNo,
+                                 unsigned DisplayLineNo,
+                                 const char *LineStart) {
+  llvm::SmallVector<StyleRange> Styles = SnippetHighlighter.highlightLine(
+      LineNo - 1, PP, LangOpts, FID, SM, LineStart);
+
   // Emit line number.
   if (MaxLineNoDisplayWidth > 0) {
-    unsigned LineNoDisplayWidth = getNumDisplayWidth(LineNo);
+    unsigned LineNoDisplayWidth = getNumDisplayWidth(DisplayLineNo);
     OS.indent(MaxLineNoDisplayWidth - LineNoDisplayWidth + 1)
-        << LineNo << " | ";
+        << DisplayLineNo << " | ";
   }
 
   // Print the source line one character at a time.
   bool PrintReversed = false;
+  bool HighlightingEnabled = DiagOpts->ShowColors;
   size_t I = 0;
   while (I < SourceLine.size()) {
     auto [Str, WasPrintable] =
         printableTextForNextCharacter(SourceLine, &I, DiagOpts->TabStop);
 
+    // Just stop highlighting anything for this line if we found a non-printable
+    // character.
+    if (!WasPrintable)
+      HighlightingEnabled = false;
+
+    // FIXME: I hope we can do this in some nicer way.
+    if (HighlightingEnabled) {
+      std::optional<enum raw_ostream::Colors> H;
----------------
cor3ntin wrote:

There is a `Colors::RESET` - we might not need an optional

https://github.com/llvm/llvm-project/pull/66514