https://github.com/tbaederr created
https://github.com/llvm/llvm-project/pull/157695
All pointer types can be null, so check that independently from the pointer
type.
Fixes #157650
>From e9a03f5cdde76fd44e4d90b5fe8fd5f999c7d4d3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbae...@redhat.com>
Date: Tue, 9 Sep 2025 17:33:13 +0200
Subject: [PATCH] [clang][bytecode] Check reads for null block pointers
All pointer types can be null, so check that independently from the
pointer type.
Fixes #157650
---
clang/lib/AST/ByteCode/Interp.cpp | 18 +++++++++---------
clang/test/AST/ByteCode/references.cpp | 18 +++++++++++++++++-
2 files changed, 26 insertions(+), 10 deletions(-)
diff --git a/clang/lib/AST/ByteCode/Interp.cpp
b/clang/lib/AST/ByteCode/Interp.cpp
index b64ed8c2fb497..b961a413fbe78 100644
--- a/clang/lib/AST/ByteCode/Interp.cpp
+++ b/clang/lib/AST/ByteCode/Interp.cpp
@@ -792,18 +792,18 @@ bool CheckLocalLoad(InterpState &S, CodePtr OpPC, const
Block *B) {
bool CheckLoad(InterpState &S, CodePtr OpPC, const Pointer &Ptr,
AccessKinds AK) {
- // Block pointers are the only ones we can actually read from.
- if (!Ptr.isBlockPointer()) {
- if (Ptr.isZero()) {
- const auto &Src = S.Current->getSource(OpPC);
+ if (Ptr.isZero()) {
+ const auto &Src = S.Current->getSource(OpPC);
- if (Ptr.isField())
- S.FFDiag(Src, diag::note_constexpr_null_subobject) << CSK_Field;
- else
- S.FFDiag(Src, diag::note_constexpr_access_null) << AK;
- }
+ if (Ptr.isField())
+ S.FFDiag(Src, diag::note_constexpr_null_subobject) << CSK_Field;
+ else
+ S.FFDiag(Src, diag::note_constexpr_access_null) << AK;
return false;
}
+ // Block pointers are the only ones we can actually read from.
+ if (!Ptr.isBlockPointer())
+ return false;
if (!Ptr.block()->isAccessible()) {
if (!CheckLive(S, OpPC, Ptr, AK))
diff --git a/clang/test/AST/ByteCode/references.cpp
b/clang/test/AST/ByteCode/references.cpp
index 36609b7df3f59..3da3996aaca75 100644
--- a/clang/test/AST/ByteCode/references.cpp
+++ b/clang/test/AST/ByteCode/references.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=ref,both
%s
constexpr int a = 10;
@@ -178,3 +178,19 @@ namespace Params {
static_assert(foo());
}
+
+namespace ReadFromNullBlockPtr {
+ struct S {
+ int *const &t;
+ };
+
+ void foo(int x) {
+ constexpr S s = {&x}; // both-error {{must be initialized by a constant
expression}} \
+ // both-note {{reference to temporary}} \
+ // both-note {{created here}} \
+ // ref-note {{declared here}}
+ static_assert(s.t == &x, ""); // both-error {{not an integral constant
expression}} \
+ // expected-note {{read of dereferenced null
pointer}} \
+ // ref-note {{initializer of 's' is not a
constant expression}}
+ }
+}
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