[Macros] Introduce SourceFile::getMacroInsertionRange for getting the

original insertion range of a macro expansion and update ASTScope creation
and ASTVerifier to use it.

Author: hborla

include/swift/AST/SourceFile.h

@@ -581,6 +581,11 @@ class SourceFile final : public FileUnit {
   /// the \c SourceFileKind is \c MacroExpansion.
   ASTNode getMacroExpansion() const;
 
+  /// For source files created to hold the source code for a macro
+  /// expansion, this is the original source range replaced by the macro
+  /// expansion.
+  SourceRange getMacroInsertionRange() const;
+
   /// For source files created to hold the source code created by expanding
   /// an attached macro, this is the custom attribute that describes the macro
   /// expansion.

lib/AST/ASTScopeCreation.cpp

@@ -284,13 +284,9 @@ ASTSourceFileScope::ASTSourceFileScope(SourceFile *SF,
     case MacroRole::Extension:
     case MacroRole::Member:
     case MacroRole::Peer:
-    case MacroRole::Preamble: {
-      auto &ctx = SF->getASTContext();
-      auto generatedSourceInfo =
-          *ctx.SourceMgr.getGeneratedSourceInfo(*SF->getBufferID());
-      parentLoc = generatedSourceInfo.originalSourceRange.getEnd();
+    case MacroRole::Preamble:
+      parentLoc = SF->getMacroInsertionRange().End;;
       break;
-    }
     case MacroRole::Body: {
       // Use the end location of the function decl itself as the parentLoc
       // for the new function body scope. This is different from the end

lib/AST/ASTVerifier.cpp

@@ -3816,8 +3816,9 @@ class Verifier : public ASTWalker {
         if (!Ctx.SourceMgr.rangeContains(Enclosing, Current)) {
           auto *expansionBuffer =
               D->getModuleContext()->getSourceFileContainingLocation(Current.Start);
-          if (auto expansion = expansionBuffer->getMacroExpansion()) {
-            Current = expansion.getSourceRange();
+
+          if (auto expansionRange = expansionBuffer->getMacroInsertionRange()) {
+            Current = expansionRange;
           }
         }
 

lib/AST/Module.cpp

@@ -1181,6 +1181,16 @@ ASTNode SourceFile::getMacroExpansion() const {
   return ASTNode::getFromOpaqueValue(genInfo.astNode);
 }
 
+SourceRange SourceFile::getMacroInsertionRange() const {
+  if (Kind != SourceFileKind::MacroExpansion)
+    return SourceRange();
+
+  auto generatedInfo =
+      *getASTContext().SourceMgr.getGeneratedSourceInfo(*getBufferID());
+  auto origRange = generatedInfo.originalSourceRange;
+  return {origRange.getStart(), origRange.getEnd()};
+}
+
 CustomAttr *SourceFile::getAttachedMacroAttribute() const {
   if (Kind != SourceFileKind::MacroExpansion)
     return nullptr;