[c++20] Add CXXRewrittenBinaryOperator to represent a comparison
operator that is rewritten as a call to multiple other operators.

No functionality change yet: nothing creates these expressions.

llvm-svn: 375305
diff --git a/clang/lib/Serialization/ASTReaderStmt.cpp b/clang/lib/Serialization/ASTReaderStmt.cpp
index 509e206..a275e0c 100644
--- a/clang/lib/Serialization/ASTReaderStmt.cpp
+++ b/clang/lib/Serialization/ASTReaderStmt.cpp
@@ -1440,6 +1440,13 @@
   E->Range = Record.readSourceRange();
 }
 
+void ASTStmtReader::VisitCXXRewrittenBinaryOperator(
+    CXXRewrittenBinaryOperator *E) {
+  VisitExpr(E);
+  E->CXXRewrittenBinaryOperatorBits.IsReversed = Record.readInt();
+  E->SemanticForm = Record.readSubExpr();
+}
+
 void ASTStmtReader::VisitCXXConstructExpr(CXXConstructExpr *E) {
   VisitExpr(E);
 
@@ -3252,6 +3259,10 @@
           Context, /*NumArgs=*/Record[ASTStmtReader::NumExprFields], Empty);
       break;
 
+    case EXPR_CXX_REWRITTEN_BINARY_OPERATOR:
+      S = new (Context) CXXRewrittenBinaryOperator(Empty);
+      break;
+
     case EXPR_CXX_CONSTRUCT:
       S = CXXConstructExpr::CreateEmpty(
           Context,
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 6f3b367..c6b05c9 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -1024,6 +1024,7 @@
   RECORD(STMT_CXX_FOR_RANGE);
   RECORD(EXPR_CXX_OPERATOR_CALL);
   RECORD(EXPR_CXX_MEMBER_CALL);
+  RECORD(EXPR_CXX_REWRITTEN_BINARY_OPERATOR);
   RECORD(EXPR_CXX_CONSTRUCT);
   RECORD(EXPR_CXX_TEMPORARY_OBJECT);
   RECORD(EXPR_CXX_STATIC_CAST);
diff --git a/clang/lib/Serialization/ASTWriterStmt.cpp b/clang/lib/Serialization/ASTWriterStmt.cpp
index 84a5324..c39d4d3 100644
--- a/clang/lib/Serialization/ASTWriterStmt.cpp
+++ b/clang/lib/Serialization/ASTWriterStmt.cpp
@@ -1375,6 +1375,14 @@
   Code = serialization::EXPR_CXX_MEMBER_CALL;
 }
 
+void ASTStmtWriter::VisitCXXRewrittenBinaryOperator(
+    CXXRewrittenBinaryOperator *E) {
+  VisitExpr(E);
+  Record.push_back(E->isReversed());
+  Record.AddStmt(E->getSemanticForm());
+  Code = serialization::EXPR_CXX_REWRITTEN_BINARY_OPERATOR;
+}
+
 void ASTStmtWriter::VisitCXXConstructExpr(CXXConstructExpr *E) {
   VisitExpr(E);