https://github.com/a-tarasyuk updated
https://github.com/llvm/llvm-project/pull/95479
>From 125d9cdd617d6415ef24eb785fe22705149f2d01 Mon Sep 17 00:00:00 2001
From: Oleksandr T <oleksandr.taras...@outlook.com>
Date: Fri, 14 Jun 2024 01:26:34 +0300
Subject: [PATCH 1/5] [Clang] disallow non-lvalue values in constant
expressions to prevent invalid pointer offset computation
---
clang/docs/ReleaseNotes.rst | 1 +
clang/lib/AST/ExprConstant.cpp | 3 +++
clang/test/Sema/integral-to-ptr.c | 3 +++
3 files changed, 7 insertions(+)
create mode 100644 clang/test/Sema/integral-to-ptr.c
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 8c2f737836a9d..755557906360b 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -847,6 +847,7 @@ Bug Fixes to C++ Support
- Fixed several bugs in capturing variables within unevaluated contexts.
(#GH63845), (#GH67260), (#GH69307),
(#GH88081), (#GH89496), (#GH90669) and (#GH91633).
- Fixed handling of brace ellison when building deduction guides. (#GH64625),
(#GH83368).
+- Fix an assertion failure caused by non-lvalue usage in lvalue context.
(GH95366).
Bug Fixes to AST Handling
^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 7178f081d9cf3..08bee806f172f 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -9325,6 +9325,9 @@ bool PointerExprEvaluator::VisitCastExpr(const CastExpr
*E) {
Result.IsNullPtr = false;
return true;
} else {
+ if (!Value.isLValue())
+ return false;
+
// Cast is of an lvalue, no need to change value.
Result.setFrom(Info.Ctx, Value);
return true;
diff --git a/clang/test/Sema/integral-to-ptr.c
b/clang/test/Sema/integral-to-ptr.c
new file mode 100644
index 0000000000000..99f83c3e52057
--- /dev/null
+++ b/clang/test/Sema/integral-to-ptr.c
@@ -0,0 +1,3 @@
+// RUN: %clang_cc1 %s -verify -fsyntax-only -std=c11
+
+int x(void) { e: b: ; return &&e - &&b < x; } // expected-warning {{ordered
comparison between pointer and integer ('long' and 'int (*)(void)')}}
>From b73cf0659a115f29c7b224a8f89ab519dac01a13 Mon Sep 17 00:00:00 2001
From: Oleksandr T <oleksandr.taras...@outlook.com>
Date: Fri, 14 Jun 2024 08:50:03 +0300
Subject: [PATCH 2/5] update test expectations
---
clang/test/Sema/integral-to-ptr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang/test/Sema/integral-to-ptr.c
b/clang/test/Sema/integral-to-ptr.c
index 99f83c3e52057..b8ab4cb79820d 100644
--- a/clang/test/Sema/integral-to-ptr.c
+++ b/clang/test/Sema/integral-to-ptr.c
@@ -1,3 +1,3 @@
// RUN: %clang_cc1 %s -verify -fsyntax-only -std=c11
-int x(void) { e: b: ; return &&e - &&b < x; } // expected-warning {{ordered
comparison between pointer and integer ('long' and 'int (*)(void)')}}
+int x(void) { e: b: ; return &&e - &&b < x; } // expected-warning {{ordered
comparison between pointer and integer}}
>From 78fc56a0aab96984760a3874e06e51259b599bd5 Mon Sep 17 00:00:00 2001
From: Oleksandr T <oleksandr.taras...@outlook.com>
Date: Fri, 14 Jun 2024 18:16:34 +0300
Subject: [PATCH 3/5] add detailed comment
---
clang/lib/AST/ExprConstant.cpp | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 08bee806f172f..712c3062eb9ac 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -9325,6 +9325,10 @@ bool PointerExprEvaluator::VisitCastExpr(const CastExpr
*E) {
Result.IsNullPtr = false;
return true;
} else {
+ // In rare instances, the value isn't an lvalue.
+ // For example, when the value is the difference between the addresses of
+ // two labels. We reject that as a constant expression because we can't
+ // compute a valid offset to convert into a pointer.
if (!Value.isLValue())
return false;
>From 7e3af56b7fbb43041f81c982cee712f516ecc6f1 Mon Sep 17 00:00:00 2001
From: Oleksandr T <oleksandr.taras...@outlook.com>
Date: Fri, 14 Jun 2024 18:16:58 +0300
Subject: [PATCH 4/5] update changelog message
---
clang/docs/ReleaseNotes.rst | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 755557906360b..efd17d8f9a089 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -847,7 +847,8 @@ Bug Fixes to C++ Support
- Fixed several bugs in capturing variables within unevaluated contexts.
(#GH63845), (#GH67260), (#GH69307),
(#GH88081), (#GH89496), (#GH90669) and (#GH91633).
- Fixed handling of brace ellison when building deduction guides. (#GH64625),
(#GH83368).
-- Fix an assertion failure caused by non-lvalue usage in lvalue context.
(GH95366).
+- Fixed a failed assertion when attempting to convert an integer representing
the difference
+ between the addresses of two labels (a GNU extension) to a pointer within a
constant expression. (GH95366).
Bug Fixes to AST Handling
^^^^^^^^^^^^^^^^^^^^^^^^^
>From 6408619fd0b0a3f06dcd096719af2d3e48ffaaf5 Mon Sep 17 00:00:00 2001
From: Oleksandr T <oleksandr.taras...@outlook.com>
Date: Mon, 17 Jun 2024 14:33:23 +0300
Subject: [PATCH 5/5] fix typo
---
clang/docs/ReleaseNotes.rst | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index b51a3effffa60..e42bd3846c929 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -859,7 +859,7 @@ Bug Fixes to C++ Support
(#GH88081), (#GH89496), (#GH90669) and (#GH91633).
- Fixed handling of brace ellison when building deduction guides. (#GH64625),
(#GH83368).
- Fixed a failed assertion when attempting to convert an integer representing
the difference
- between the addresses of two labels (a GNU extension) to a pointer within a
constant expression. (GH95366).
+ between the addresses of two labels (a GNU extension) to a pointer within a
constant expression. (#GH95366).
Bug Fixes to AST Handling
^^^^^^^^^^^^^^^^^^^^^^^^^
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