[AST] Teach TextNodeDumper to print the "implicit" bit for coroutine AST nodes (llvm#77311)

Author: hokein

clang/include/clang/AST/TextNodeDumper.h

@@ -252,6 +252,8 @@ class TextNodeDumper
   void VisitGotoStmt(const GotoStmt *Node);
   void VisitCaseStmt(const CaseStmt *Node);
   void VisitReturnStmt(const ReturnStmt *Node);
+  void VisitCoawaitExpr(const CoawaitExpr *Node);
+  void VisitCoreturnStmt(const CoreturnStmt *Node);
   void VisitCompoundStmt(const CompoundStmt *Node);
   void VisitConstantExpr(const ConstantExpr *Node);
   void VisitCallExpr(const CallExpr *Node);

clang/lib/AST/TextNodeDumper.cpp

@@ -1094,6 +1094,16 @@ void clang::TextNodeDumper::VisitReturnStmt(const ReturnStmt *Node) {
   }
 }
 
+void clang::TextNodeDumper::VisitCoawaitExpr(const CoawaitExpr *Node) {
+  if (Node->isImplicit())
+    OS << " implicit";
+}
+
+void clang::TextNodeDumper::VisitCoreturnStmt(const CoreturnStmt *Node) {
+  if (Node->isImplicit())
+    OS << " implicit";
+}
+
 void TextNodeDumper::VisitConstantExpr(const ConstantExpr *Node) {
   if (Node->hasAPValueResult())
     AddChild("value",

clang/test/AST/ast-dump-coroutine.cpp

@@ -0,0 +1,69 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -std=c++20 \
+// RUN:    -fsyntax-only -ast-dump -ast-dump-filter test | FileCheck %s
+
+#include "Inputs/std-coroutine.h"
+
+using namespace std;
+
+struct Task {
+  struct promise_type {
+    std::suspend_always initial_suspend() { return {}; }
+    Task get_return_object() {
+      return std::coroutine_handle<promise_type>::from_promise(*this);
+    }
+    std::suspend_always final_suspend() noexcept { return {}; }
+    std::suspend_always return_void() { return {}; }
+    void unhandled_exception() {}
+
+    auto await_transform(int s) {
+      struct awaiter {
+        promise_type *promise;
+        bool await_ready() { return true; }
+        int await_resume() { return 1; }
+        void await_suspend(std::coroutine_handle<>) {}
+      };
+
+      return awaiter{this};
+    }
+  };
+
+  Task(std::coroutine_handle<promise_type> promise);
+
+  std::coroutine_handle<promise_type> handle;
+};
+
+Task test()  {
+  co_await 1;
+// Writen souce code, verify no implicit bit for the co_await expr.
+// CHECK:        CompoundStmt {{.*}}
+// CHECK-NEXT:   | `-ExprWithCleanups {{.*}} 'int'
+// CHECK-NEXT:   |   `-CoawaitExpr {{.*}} 'int'{{$}}
+// CHECK-NEXT:   |     |-IntegerLiteral {{.*}} <col:12> 'int' 1
+// CHECK-NEXT:   |     |-MaterializeTemporaryExpr {{.*}} 'awaiter'
+// CHECK-NEXT:   |     | `-CXXMemberCallExpr {{.*}} 'awaiter'
+// CHECK-NEXT:   |     |   |-MemberExpr {{.*}} .await_transform
+}
+// Verify the implicit AST nodes for coroutines.
+// CHECK:        |-DeclStmt {{.*}}
+// CHECK-NEXT:   | `-VarDecl {{.*}} implicit used __promise
+// CHECK-NEXT:   |   `-CXXConstructExpr {{.*}}
+// CHECK-NEXT:   |-ExprWithCleanups {{.*}} 'void'
+// CHECK-NEXT:   | `-CoawaitExpr {{.*}} 'void' implicit
+// CHECK-NEXT:       |-CXXMemberCallExpr  {{.*}} 'std::suspend_always'
+// CHECK-NEXT:       |   | `-MemberExpr {{.*}} .initial_suspend
+//                   ...
+// FIXME: the CoreturnStmt should be marked as implicit
+// CHECK: CoreturnStmt {{.*}} <col:6>{{$}}
+
+Task test2()  {
+// Writen souce code, verify no implicit bit for the co_return expr.
+// CHECK:        CompoundStmt {{.*}}
+// CHECK-NEXT:   | `-CoreturnStmt {{.*}} <line:{{.*}}:{{.*}}>{{$}}
+  co_return;
+}
+// Verify the implicit AST nodes for coroutines.
+// CHECK:        |-DeclStmt {{.*}}
+// CHECK-NEXT:   | `-VarDecl {{.*}} implicit used __promise
+//               ...
+// FIXME: the CoreturnStmt should be marked as implicit
+// CHECK: CoreturnStmt {{.*}} <col:6>{{$}}