[clang][ASTImporter] Add import support for SourceLocExpr.

[balazske]

Summary

It is possible that imported SourceLocExpr can cause not expected behavior (if __builtin_LINE() is used together with __LINE__ for example) but still it may be worth to import these because some projects use it.

clang/lib/AST/ASTImporter.cpp

public:
     ExpectedStmt VisitObjCAtFinallyStmt(ObjCAtFinallyStmt *S);
     ExpectedStmt VisitObjCAtTryStmt(ObjCAtTryStmt *S);
     ExpectedStmt VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S);
     ExpectedStmt VisitObjCAtThrowStmt(ObjCAtThrowStmt *S);
     ExpectedStmt VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S);
 
     // Importing expressions
     ExpectedStmt VisitExpr(Expr *E);
+    ExpectedStmt VisitSourceLocExpr(SourceLocExpr *E);
     ExpectedStmt VisitVAArgExpr(VAArgExpr *E);
     ExpectedStmt VisitChooseExpr(ChooseExpr *E);
     ExpectedStmt VisitGNUNullExpr(GNUNullExpr *E);
     ExpectedStmt VisitGenericSelectionExpr(GenericSelectionExpr *E);
     ExpectedStmt VisitPredefinedExpr(PredefinedExpr *E);
     ExpectedStmt VisitDeclRefExpr(DeclRefExpr *E);
     ExpectedStmt VisitImplicitValueInitExpr(ImplicitValueInitExpr *E);
     ExpectedStmt VisitDesignatedInitExpr(DesignatedInitExpr *E);

 // Import Expressions
 //----------------------------------------------------------------------------
 ExpectedStmt ASTNodeImporter::VisitExpr(Expr *E) {
   Importer.FromDiag(E->getBeginLoc(), diag::err_unsupported_ast_node)
       << E->getStmtClassName();
   return make_error<ImportError>(ImportError::UnsupportedConstruct);
 }
 
+ExpectedStmt ASTNodeImporter::VisitSourceLocExpr(SourceLocExpr *E) {
+  Error Err = Error::success();
+  auto BLoc = importChecked(Err, E->getBeginLoc());
+  auto RParenLoc = importChecked(Err, E->getEndLoc());
+  if (Err)
+    return std::move(Err);
+  auto ParentContextOrErr = Importer.ImportContext(E->getParentContext());
+  if (!ParentContextOrErr)
+    return ParentContextOrErr.takeError();
+
+  return new (Importer.getToContext())
+      SourceLocExpr(Importer.getToContext(), E->getIdentKind(), BLoc, RParenLoc,
+                    *ParentContextOrErr);
+}
+
 ExpectedStmt ASTNodeImporter::VisitVAArgExpr(VAArgExpr *E) {
 
   Error Err = Error::success();
   auto ToBuiltinLoc = importChecked(Err, E->getBuiltinLoc());
   auto ToSubExpr = importChecked(Err, E->getSubExpr());
   auto ToWrittenTypeInfo = importChecked(Err, E->getWrittenTypeInfo());
   auto ToRParenLoc = importChecked(Err, E->getRParenLoc());
   auto ToType = importChecked(Err, E->getType());

clang/unittests/AST/ASTImporterTest.cpp

TEST_P(ImportPath, CycleAfterCycle) {
   EXPECT_EQ(Res[0], D0);
   EXPECT_EQ(Res[1], D1);
   EXPECT_EQ(Res[2], D0);
 
   path.pop();
   EXPECT_FALSE(path.hasCycleAtBack());
 }
 
+const internal::VariadicDynCastAllOfMatcher<Stmt, SourceLocExpr> sourceLocExpr;
+
+AST_MATCHER_P(SourceLocExpr, hasBuiltinStr, StringRef, Str) {
+  return Node.getBuiltinStr() == Str;
+}
+
+TEST_P(ImportExpr, ImportSourceLocExpr) {
+  MatchVerifier<Decl> Verifier;
+  testImport("void declToImport() { (void)__builtin_FILE(); }", Lang_CXX03, "",
+             Lang_CXX03, Verifier,
+             functionDecl(hasDescendant(
+                 sourceLocExpr(hasBuiltinStr("__builtin_FILE")))));
+  testImport("void declToImport() { (void)__builtin_COLUMN(); }", Lang_CXX03,
+             "", Lang_CXX03, Verifier,
+             functionDecl(hasDescendant(
+                 sourceLocExpr(hasBuiltinStr("__builtin_COLUMN")))));
+}
+
 TEST_P(ImportExpr, ImportStringLiteral) {
   MatchVerifier<Decl> Verifier;
   testImport("void declToImport() { (void)\"foo\"; }", Lang_CXX03, "",
              Lang_CXX03, Verifier,
              functionDecl(hasDescendant(
                  stringLiteral(hasType(asString("const char [4]"))))));
   testImport("void declToImport() { (void)L\"foo\"; }", Lang_CXX03, "",
              Lang_CXX03, Verifier,