https://github.com/tbaederr updated
https://github.com/llvm/llvm-project/pull/137211
>From 9388799f1a7bb4d6bbfc467db569aa61c4666445 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbae...@redhat.com>
Date: Thu, 24 Apr 2025 18:29:36 +0200
Subject: [PATCH] [clang][bytecode] Allow forming pointers to fields of extern
globals
This should be fine as long as we're not reading from it.
Note that this regresses
CXX/special/class.init/class.inhctor.init/p1.cpp, which used to work
fine with the bytecode interpreter.
That's because this code now fails:
struct Param;
struct A {
constexpr A(Param);
int a;
};
struct B : A { B(); using A::A; int b = 2; };
struct Wrap1 : B { constexpr Wrap1(); };
struct Wrap2 : Wrap1 {};
extern const Wrap2 b;
struct Param {
constexpr Param(int c) : n(4 * b.a + b.b + c) {}
int n;
};
and reports that the Param() constructor is never a valid constant
expression. But that's true and the current interpeter should
report that as well. It also fails when calling at compile time.
---
clang/lib/AST/ByteCode/Interp.cpp | 2 --
clang/test/AST/ByteCode/cxx11.cpp | 6 ++++++
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/clang/lib/AST/ByteCode/Interp.cpp
b/clang/lib/AST/ByteCode/Interp.cpp
index 6f277a7488836..23fd894bd6a3e 100644
--- a/clang/lib/AST/ByteCode/Interp.cpp
+++ b/clang/lib/AST/ByteCode/Interp.cpp
@@ -1323,8 +1323,6 @@ static bool getField(InterpState &S, CodePtr OpPC, const
Pointer &Ptr,
!CheckNull(S, OpPC, Ptr, CSK_Field))
return false;
- if (!CheckExtern(S, OpPC, Ptr))
- return false;
if (!CheckRange(S, OpPC, Ptr, CSK_Field))
return false;
if (!CheckArray(S, OpPC, Ptr))
diff --git a/clang/test/AST/ByteCode/cxx11.cpp
b/clang/test/AST/ByteCode/cxx11.cpp
index 5daf6adf08cf5..cb05f26d11206 100644
--- a/clang/test/AST/ByteCode/cxx11.cpp
+++ b/clang/test/AST/ByteCode/cxx11.cpp
@@ -202,3 +202,9 @@ namespace GlobalInitializer {
// both-note {{initializer of 'g' is unknown}}
};
}
+
+namespace ExternPointer {
+ struct S { int a; };
+ extern const S pu;
+ constexpr const int *pua = &pu.a; // Ok.
+}
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