https://github.com/mizvekov created
https://github.com/llvm/llvm-project/pull/101447
Since 3bf72d7d64b8465acd4f4af1a469d68d9dc86058 we have made a simplification
where we transform a string literal into a prvalue, where normally they would
always be lvalues.
This patch fixes expression classification to account for this case.
Fixes #82167
>From 345d5d15f7d8992ce1ecd575f83ea85088bb27c1 Mon Sep 17 00:00:00 2001
From: Matheus Izvekov <mizve...@gmail.com>
Date: Thu, 1 Aug 2024 00:01:19 -0300
Subject: [PATCH] [clang] fix classification of a string literal expression
used as initialzier
Since 3bf72d7d64b8465acd4f4af1a469d68d9dc86058 we have made a
simplification where we transform a string literal into a prvalue,
where normally they would always be lvalues.
This patch fixes expression classification to account for this
case.
Fixes #82167
---
clang/docs/ReleaseNotes.rst | 4 +++-
clang/lib/AST/ExprClassification.cpp | 8 ++++++--
clang/test/SemaCXX/GH82167.cpp | 15 +++++++++++++++
3 files changed, 24 insertions(+), 3 deletions(-)
create mode 100644 clang/test/SemaCXX/GH82167.cpp
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 3c2e0282d1c72..c4dca7252e87a 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -130,7 +130,7 @@ Improvements to Clang's diagnostics
- Some template related diagnostics have been improved.
.. code-block:: c++
-
+
void foo() { template <typename> int i; } // error: templates can only be
declared in namespace or class scope
struct S {
@@ -170,6 +170,8 @@ Bug Fixes to C++ Support
- Fixed a failed assertion when checking invalid delete operator declaration.
(#GH96191)
- Fix a crash when checking destructor reference with an invalid initializer.
(#GH97230)
- Clang now correctly parses potentially declarative nested-name-specifiers in
pointer-to-member declarators.
+- Fix a crash when checking the initialzier of an object that was initialized
+ with a string literal. (#GH82167)
Bug Fixes to AST Handling
^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/AST/ExprClassification.cpp
b/clang/lib/AST/ExprClassification.cpp
index 6482cb6d39acc..3b3c0af826079 100644
--- a/clang/lib/AST/ExprClassification.cpp
+++ b/clang/lib/AST/ExprClassification.cpp
@@ -119,8 +119,6 @@ static Cl::Kinds ClassifyInternal(ASTContext &Ctx, const
Expr *E) {
// First come the expressions that are always lvalues, unconditionally.
case Expr::ObjCIsaExprClass:
- // C++ [expr.prim.general]p1: A string literal is an lvalue.
- case Expr::StringLiteralClass:
// @encode is equivalent to its string
case Expr::ObjCEncodeExprClass:
// __func__ and friends are too.
@@ -150,6 +148,12 @@ static Cl::Kinds ClassifyInternal(ASTContext &Ctx, const
Expr *E) {
case Expr::OMPIteratorExprClass:
return Cl::CL_LValue;
+ // C++ [expr.prim.general]p1: A string literal is an lvalue.
+ // Except we special case them as prvalues when they are used for
+ // initialization.
+ case Expr::StringLiteralClass:
+ return E->isLValue() ? Cl::CL_LValue : Cl::CL_PRValue;
+
// C99 6.5.2.5p5 says that compound literals are lvalues.
// In C++, they're prvalue temporaries, except for file-scope arrays.
case Expr::CompoundLiteralExprClass:
diff --git a/clang/test/SemaCXX/GH82167.cpp b/clang/test/SemaCXX/GH82167.cpp
new file mode 100644
index 0000000000000..0e13a5a3e1b6d
--- /dev/null
+++ b/clang/test/SemaCXX/GH82167.cpp
@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -std=c++23 -fsyntax-only
-verify %s
+// expected-no-diagnostics
+
+namespace t1 {
+ struct array {
+ char elems[2];
+ };
+
+ template <unsigned> struct Literal {
+ array arr;
+ constexpr Literal() : arr("") {}
+ };
+
+ template struct Literal<0>;
+} // namespace t1
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