1 files changed, 49 insertions, 0 deletions
diff --git a/clang/lib/AST/DataCollection.cpp b/clang/lib/AST/DataCollection.cpp
new file mode 100644
index 000000000000..8e67c101dee1
--- /dev/null
+++ b/clang/lib/AST/DataCollection.cpp
@@ -0,0 +1,49 @@
+//===-- DataCollection.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 "clang/AST/DataCollection.h"
+
+#include "clang/Lex/Lexer.h"
+
+namespace clang {
+namespace data_collection {
+
+/// Prints the macro name that contains the given SourceLocation into the given
+/// raw_string_ostream.
+static void printMacroName(llvm::raw_string_ostream &MacroStack,
+                           ASTContext &Context, SourceLocation Loc) {
+  MacroStack << Lexer::getImmediateMacroName(Loc, Context.getSourceManager(),
+                                             Context.getLangOpts());
+
+  // Add an empty space at the end as a padding to prevent
+  // that macro names concatenate to the names of other macros.
+  MacroStack << " ";
+}
+
+/// Returns a string that represents all macro expansions that expanded into the
+/// given SourceLocation.
+///
+/// If 'getMacroStack(A) == getMacroStack(B)' is true, then the SourceLocations
+/// A and B are expanded from the same macros in the same order.
+std::string getMacroStack(SourceLocation Loc, ASTContext &Context) {
+  std::string MacroStack;
+  llvm::raw_string_ostream MacroStackStream(MacroStack);
+  SourceManager &SM = Context.getSourceManager();
+
+  // Iterate over all macros that expanded into the given SourceLocation.
+  while (Loc.isMacroID()) {
+    // Add the macro name to the stream.
+    printMacroName(MacroStackStream, Context, Loc);
+    Loc = SM.getImmediateMacroCallerLoc(Loc);
+  }
+  MacroStackStream.flush();
+  return MacroStack;
+}
+
+} // end namespace data_collection
+} // end namespace clang