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

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


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@@ -0,0 +1,187 @@
+//===-- CodeSnippetHighlighter.cpp - Code snippet highlighting --*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Frontend/CodeSnippetHighlighter.h"
+#include "clang/Basic/DiagnosticOptions.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Lex/Lexer.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Lex/PreprocessorOptions.h"
+#include "llvm/Support/raw_ostream.h"
+#include <chrono>
+
+using namespace clang;
+
+static constexpr raw_ostream::Colors CommentColor = raw_ostream::GREEN;
+static constexpr raw_ostream::Colors LiteralColor = raw_ostream::CYAN;
+static constexpr raw_ostream::Colors KeywordColor = raw_ostream::BLUE;
+
+llvm::SmallVector<StyleRange> CodeSnippetHighlighter::highlightLine(
+    unsigned LineNumber, const Preprocessor *PP, const LangOptions &LangOpts,
+    FileID FID, const SourceManager &SM, const char *LineStart) {
+  std::chrono::steady_clock::time_point begin =
+      std::chrono::steady_clock::now();
+
+  if (!PP)
+    return {};
+
+  // Might cause emission of another diagnostic.
+  if (PP->getIdentifierTable().getExternalIdentifierLookup())
+    return {};
+
+  size_t NTokens = 0;
+  // Classify the given token and append it to the given vector.
+  auto appendStyle = [PP, &LangOpts](llvm::SmallVector<StyleRange> &Vec,
+                                     const Token &T, unsigned Start,
+                                     unsigned Length) -> void {
+    if (T.is(tok::raw_identifier)) {
+      StringRef RawIdent = T.getRawIdentifier();
+      // Special case true/false/nullptr literals, since they will otherwise be
+      // treated as keywords.
+      if (RawIdent == "true" || RawIdent == "false" || RawIdent == "nullptr") {
+        Vec.push_back(StyleRange{Start, Start + Length, LiteralColor});
----------------
cor3ntin wrote:

you can use `emplace_back` everywhere

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