[clang] [clang][bytecode] Check destructors for temporaries (PR #140039)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Timm Baeder (tbaederr)

<details>
<summary>Changes</summary>

Also, increase the EvalID in isPotentialConstantExpr(), since this is its own evaluation.

---
Full diff: https://github.com/llvm/llvm-project/pull/140039.diff


3 Files Affected:

- (modified) clang/lib/AST/ByteCode/Context.cpp (+1) 
- (modified) clang/lib/AST/ByteCode/Interp.cpp (+2) 
- (modified) clang/test/AST/ByteCode/cxx20.cpp (+10) 


``````````diff
diff --git a/clang/lib/AST/ByteCode/Context.cpp b/clang/lib/AST/ByteCode/Context.cpp
index dae94fc9829c7..c70a5259b77e2 100644
--- a/clang/lib/AST/ByteCode/Context.cpp
+++ b/clang/lib/AST/ByteCode/Context.cpp
@@ -37,6 +37,7 @@ bool Context::isPotentialConstantExpr(State &Parent, const FunctionDecl *FD) {
   Compiler<ByteCodeEmitter>(*this, *P).compileFunc(
       FD, const_cast<Function *>(Func));
 
+  ++EvalID;
   // And run it.
   if (!Run(Parent, Func))
     return false;
diff --git a/clang/lib/AST/ByteCode/Interp.cpp b/clang/lib/AST/ByteCode/Interp.cpp
index bc860185fea21..fbe04fe3231dd 100644
--- a/clang/lib/AST/ByteCode/Interp.cpp
+++ b/clang/lib/AST/ByteCode/Interp.cpp
@@ -1373,6 +1373,8 @@ static bool checkConstructor(InterpState &S, CodePtr OpPC, const Function *Func,
 bool CheckDestructor(InterpState &S, CodePtr OpPC, const Pointer &Ptr) {
   if (!CheckLive(S, OpPC, Ptr, AK_Destroy))
     return false;
+  if (!CheckTemporary(S, OpPC, Ptr, AK_Destroy))
+    return false;
 
   // Can't call a dtor on a global variable.
   if (Ptr.block()->isStatic()) {
diff --git a/clang/test/AST/ByteCode/cxx20.cpp b/clang/test/AST/ByteCode/cxx20.cpp
index 8fb19fcfcd3fe..5f62a5648bab7 100644
--- a/clang/test/AST/ByteCode/cxx20.cpp
+++ b/clang/test/AST/ByteCode/cxx20.cpp
@@ -997,3 +997,13 @@ namespace NastyChar {
   template <ToNastyChar t> constexpr auto to_nasty_char() { return t; }
   constexpr auto result = to_nasty_char<"12345">();
 }
+
+namespace TempDtor {
+  struct A {
+    int n;
+  };
+  constexpr A &&a_ref = A(); // both-note {{temporary created here}}
+  constexpr void destroy_extern_2() { // both-error {{never produces a constant expression}}
+    a_ref.~A(); // both-note {{destruction of temporary is not allowed in a constant expression outside the expression that created the temporary}}
+  }
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/140039