diff --git a/clang-tools-extra/clangd/CMakeLists.txt b/clang-tools-extra/clangd/CMakeLists.txt
--- a/clang-tools-extra/clangd/CMakeLists.txt
+++ b/clang-tools-extra/clangd/CMakeLists.txt
@@ -62,6 +62,7 @@
   Quality.cpp
   RIFF.cpp
   Selection.cpp
+  SemanticHighlight.cpp
   SourceCode.cpp
   Threading.cpp
   Trace.cpp
diff --git a/clang-tools-extra/clangd/SemanticHighlight.h b/clang-tools-extra/clangd/SemanticHighlight.h
new file mode 100644
--- /dev/null
+++ b/clang-tools-extra/clangd/SemanticHighlight.h
@@ -0,0 +1,38 @@
+//==-- SemanticHighlight.h - Generating highlights from the AST--*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_SEMANTICHIGHLIGHT_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_SEMANTICHIGHLIGHT_H
+
+#include "ClangdUnit.h"
+#include "Protocol.h"
+#include "clang/AST/RecursiveASTVisitor.h"
+
+namespace clang {
+namespace clangd {
+
+enum class SemanticHighlightKind : int {
+  Variable = 0,
+  Function = 1,
+};
+
+// Contains all information needed for the highlighting a token.
+struct SemanticToken {
+  SemanticHighlightKind Kind;
+  Range R;
+};
+
+bool operator==(const SemanticToken &Lhs, const SemanticToken &Rhs);
+bool operator!=(const SemanticToken &Lhs, const SemanticToken &Rhs);
+
+std::vector<SemanticToken> getSemanticHighlights(ParsedAST &AST);
+
+} // namespace clangd
+} // namespace clang
+
+#endif
\ No newline at end of file
diff --git a/clang-tools-extra/clangd/SemanticHighlight.cpp b/clang-tools-extra/clangd/SemanticHighlight.cpp
new file mode 100644
--- /dev/null
+++ b/clang-tools-extra/clangd/SemanticHighlight.cpp
@@ -0,0 +1,94 @@
+//===--- SemanticHighlight.cpp - -------------------------- -----*- 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 "SemanticHighlight.h"
+#include "SourceCode.h"
+#include "clang/Lex/Lexer.h"
+
+namespace clang {
+namespace clangd {
+namespace {
+
+// Collects all semantic tokens in an ASTContext.
+class SemanticTokenCollector
+    : private RecursiveASTVisitor<SemanticTokenCollector> {
+  friend class RecursiveASTVisitor<SemanticTokenCollector>;
+  std::vector<SemanticToken> Tokens;
+  ASTContext &Ctx;
+  const SourceManager &SM;
+
+public:
+  SemanticTokenCollector(ParsedAST &AST)
+      : Ctx(AST.getASTContext()), SM(AST.getSourceManager()) {
+    auto TopDecls = AST.getLocalTopLevelDecls();
+    std::vector<Decl *> FilteredTopDecls;
+    // If a top level decl is not part of the main file it can't be highlighted.
+    for (auto Decl : TopDecls) {
+      if (AST.getSourceManager().getFileID(Decl->getLocation()) ==
+          AST.getSourceManager().getMainFileID()) {
+        FilteredTopDecls.push_back(Decl);
+      }
+    }
+
+    Ctx.setTraversalScope(FilteredTopDecls);
+  }
+
+  std::vector<SemanticToken> collectTokens() {
+    TraverseAST(Ctx);
+    return Tokens;
+  }
+
+private:
+  bool VisitVarDecl(VarDecl *Var) {
+    addSymbol(Var, SemanticHighlightKind::Variable);
+    return true;
+  }
+  bool VisitFunctionDecl(FunctionDecl *Func) {
+    addSymbol(Func, SemanticHighlightKind::Function);
+    return true;
+  }
+
+  void addSymbol(NamedDecl *D, SemanticHighlightKind Kind) {
+    if (D->getLocation().isMacroID()) {
+      // FIXME; This is inside a macro. For now skip the token
+      return;
+    }
+
+    if (D->getName().size() == 0) {
+      // Don't add symbols that don't have any length.
+      return;
+    }
+
+    auto R = getTokenRange(SM, Ctx.getLangOpts(), D->getLocation());
+    if (!R.hasValue()) {
+      // R should always have a value, if it doesn't something is very wrong.
+      llvm_unreachable("Tried to add semantic token with an invalid range");
+    }
+
+    SemanticToken S;
+    S.R = R.getValue();
+    S.Kind = Kind;
+    Tokens.push_back(S);
+  }
+};
+
+} // namespace
+
+bool operator==(const SemanticToken &Lhs, const SemanticToken &Rhs) {
+  return Lhs.Kind == Rhs.Kind && Lhs.R == Rhs.R;
+}
+bool operator!=(const SemanticToken &Lhs, const SemanticToken &Rhs) {
+  return !(Lhs == Rhs);
+}
+
+std::vector<SemanticToken> getSemanticHighlights(ParsedAST &AST) {
+  return SemanticTokenCollector(AST).collectTokens();
+}
+
+} // namespace clangd
+} // namespace clang
diff --git a/clang-tools-extra/clangd/unittests/CMakeLists.txt b/clang-tools-extra/clangd/unittests/CMakeLists.txt
--- a/clang-tools-extra/clangd/unittests/CMakeLists.txt
+++ b/clang-tools-extra/clangd/unittests/CMakeLists.txt
@@ -53,6 +53,7 @@
   RenameTests.cpp
   RIFFTests.cpp
   SelectionTests.cpp
+  SemanticHighlightTests.cpp
   SerializationTests.cpp
   SourceCodeTests.cpp
   SymbolCollectorTests.cpp
diff --git a/clang-tools-extra/clangd/unittests/SemanticHighlightTests.cpp b/clang-tools-extra/clangd/unittests/SemanticHighlightTests.cpp
new file mode 100644
--- /dev/null
+++ b/clang-tools-extra/clangd/unittests/SemanticHighlightTests.cpp
@@ -0,0 +1,73 @@
+//===- SemanticHighlightTest.cpp - SemanticHighlightTest tests-*- 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 "Annotations.h"
+#include "ClangdUnit.h"
+#include "Protocol.h"
+#include "SemanticHighlight.h"
+#include "SourceCode.h"
+#include "TestTU.h"
+#include "llvm/Support/ScopedPrinter.h"
+#include "gmock/gmock-matchers.h"
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+
+namespace clang {
+namespace clangd {
+namespace {
+
+std::vector<SemanticToken> makeSemanticTokens(std::vector<Range> Ranges,
+                                             SemanticHighlightKind Kind) {
+  std::vector<SemanticToken> Tokens(Ranges.size());
+  for (int I = 0, End = Ranges.size(); I < End; I++) {
+    Tokens[I].R = Ranges[I];
+    Tokens[I].Kind = Kind;
+  }
+
+  return Tokens;
+}
+
+void checkHighlights(std::string Code) {
+
+  Annotations Test(Code);
+  auto AST = TestTU::withCode(Test.code()).build();
+  std::map<SemanticHighlightKind, std::string> KindToString{
+      {SemanticHighlightKind::Variable, "Variable"},
+      {SemanticHighlightKind::Function, "Function"}};
+  std::vector<SemanticToken> ExpectedTokens;
+  for (auto KindString : KindToString) {
+    std::vector<SemanticToken> Toks =
+        makeSemanticTokens(Test.ranges(KindString.second), KindString.first);
+    ExpectedTokens.insert(ExpectedTokens.end(), Toks.begin(), Toks.end());
+  }
+
+  auto ActualTokens = getSemanticHighlights(AST);
+  EXPECT_THAT(ActualTokens, testing::UnorderedElementsAreArray(ExpectedTokens));
+}
+
+TEST(SemanticTokenCollector, GetBeginningOfIdentifier) {
+  checkHighlights(R"cpp(
+    struct A {
+      double SomeMember;
+    };
+    void $Function[[foo]](int $Variable[[a]]) {
+      auto $Variable[[VeryLongVariableName]] = 12312;
+      A     $Variable[[aa]];
+    }
+  )cpp");
+}
+
+TEST(SemanticTokenCollector, DoesNotGetUnnamedParamDecls) {
+  checkHighlights(R"cpp(
+    void $Function[[foo]](int);
+  )cpp");
+}
+
+} // namespace
+} // namespace clangd
+} // namespace clang