Reland [clang][DeclPrinter] Fix missing semicolon in AST print for methods that are definitions without having a body

DeclPrinter used FunctionDecl::isThisDeclarationADefinition to decide if the decl requires a semicolon at the end. However, there are several methods without body (that require a semicolon) that are definitions.

Fixes #62996

Initial commit had a failing test case on targets not supporting `__attribute__((alias))`. Added `-triple i386-linux-gnu` to the specific test case.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D156533

Author: strimo378

clang/lib/AST/DeclPrinter.cpp

@@ -463,12 +463,12 @@ void DeclPrinter::VisitDeclContext(DeclContext *DC, bool Indent) {
     else if (isa<ObjCMethodDecl>(*D) && cast<ObjCMethodDecl>(*D)->hasBody())
       Terminator = nullptr;
     else if (auto FD = dyn_cast<FunctionDecl>(*D)) {
-      if (FD->isThisDeclarationADefinition())
+      if (FD->doesThisDeclarationHaveABody() && !FD->isDefaulted())
         Terminator = nullptr;
       else
         Terminator = ";";
     } else if (auto TD = dyn_cast<FunctionTemplateDecl>(*D)) {
-      if (TD->getTemplatedDecl()->isThisDeclarationADefinition())
+      if (TD->getTemplatedDecl()->doesThisDeclarationHaveABody())
         Terminator = nullptr;
       else
         Terminator = ";";

clang/test/AST/ast-print-method-decl.cpp

@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -ast-print %s -o - -std=c++20 | FileCheck %s
+// RUN: %clang_cc1 -ast-print -triple i386-linux-gnu %s -o - -std=c++20 | FileCheck %s
 
 // CHECK: struct DelegatingCtor1 {
 struct DelegatingCtor1 {
@@ -85,3 +85,18 @@ struct CurlyCtorInit {
 
   // CHECK-NEXT: };
 };
+
+
+// CHECK: struct DefMethodsWithoutBody {
+struct DefMethodsWithoutBody {
+  // CHECK-NEXT: DefMethodsWithoutBody() = delete;
+  DefMethodsWithoutBody() = delete;
+
+  // CHECK-NEXT: DefMethodsWithoutBody() = default;
+  ~DefMethodsWithoutBody() = default;
+
+  // CHECK-NEXT: void m1() __attribute__((alias("X")));
+  void m1() __attribute__((alias("X")));
+
+  // CHECK-NEXT: };
+};