https://github.com/tbaederr created
https://github.com/llvm/llvm-project/pull/137357
None
>From 6b572e0de6874d94f8b7ae4b269e07f1451956b8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbae...@redhat.com>
Date: Fri, 25 Apr 2025 13:17:14 +0200
Subject: [PATCH] [clang][bytecode] Diagnose destroying already dead locals
---
clang/lib/AST/ByteCode/Interp.h | 15 +++++++++++++++
clang/test/AST/ByteCode/lifetimes.cpp | 18 ++++++++++++++++--
2 files changed, 31 insertions(+), 2 deletions(-)
diff --git a/clang/lib/AST/ByteCode/Interp.h b/clang/lib/AST/ByteCode/Interp.h
index 0cfeed86f0b51..9b3d312b547de 100644
--- a/clang/lib/AST/ByteCode/Interp.h
+++ b/clang/lib/AST/ByteCode/Interp.h
@@ -2197,6 +2197,21 @@ inline bool SubPtr(InterpState &S, CodePtr OpPC) {
//===----------------------------------------------------------------------===//
inline bool Destroy(InterpState &S, CodePtr OpPC, uint32_t I) {
+ assert(S.Current->getFunction());
+
+ // FIXME: We iterate the scope once here and then again in the destroy() call
+ // below.
+ for (auto &Local : S.Current->getFunction()->getScope(I).locals_reverse()) {
+ const Pointer &Ptr = S.Current->getLocalPointer(Local.Offset);
+
+ if (Ptr.getLifetime() == Lifetime::Ended) {
+ auto *D = cast<NamedDecl>(Ptr.getFieldDesc()->asDecl());
+ S.FFDiag(D->getLocation(), diag::note_constexpr_destroy_out_of_lifetime)
+ << D->getNameAsString();
+ return false;
+ }
+ }
+
S.Current->destroy(I);
return true;
}
diff --git a/clang/test/AST/ByteCode/lifetimes.cpp
b/clang/test/AST/ByteCode/lifetimes.cpp
index 43039d0c766e9..17f8d4e24bd85 100644
--- a/clang/test/AST/ByteCode/lifetimes.cpp
+++ b/clang/test/AST/ByteCode/lifetimes.cpp
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 -fexperimental-new-constant-interpreter
-verify=expected,both %s
-// RUN: %clang_cc1 -verify=ref,both %s
+// RUN: %clang_cc1 -verify=expected,both -std=c++20 %s
-fexperimental-new-constant-interpreter
+// RUN: %clang_cc1 -verify=ref,both -std=c++20 %s
/// FIXME: Slight difference in diagnostic output here.
@@ -68,3 +68,17 @@ namespace PrimitiveMoveFn {
const float &x = y;
}
}
+
+/// FIXME:
+/// 1) This doesn't work for parameters
+/// 2) We need to do this for all fields in composite scenarios
+namespace PseudoDtor {
+ typedef int I;
+ constexpr bool foo() { // both-error {{never produces a constant expression}}
+ {
+ int a; // both-note {{destroying object 'a' whose lifetime has already
ended}}
+ a.~I();
+ }
+ return true;
+ }
+}
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