commit bc57b108b2253e26b83768dba196c28564952f18
author Richard Smith <richard-llvm@metafoo.co.uk> Sat Sep 15 06:09:58 2012 +0000
committer Richard Smith <richard-llvm@metafoo.co.uk> Sat Sep 15 06:09:58 2012 +0000
tree 60857949ef502f062cd8fff6a9812220816a6c28
parent e6664f43bb3ed95c9cd059fac89740cb2d976c15

const _Atomic(T) is not an atomic type, so do not allow it as the type 'A' in
C11 7.17's atomic operations. GNU's __atomic_* builtins do allow const-qualified
atomics, though (!!) so don't restrict those.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@163964 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Basic/DiagnosticSemaKinds.td

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 04eb757..db3e629 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -4946,6 +4946,9 @@
 def err_atomic_op_needs_atomic : Error<
   "first argument to atomic operation must be a pointer to _Atomic "
   "type (%0 invalid)">;
+def err_atomic_op_needs_non_const_atomic : Error<
+  "first argument to atomic operation must be a pointer to non-const _Atomic "
+  "type (%0 invalid)">;
 def err_atomic_op_needs_trivial_copy : Error<
   "first argument to atomic operation must be a pointer to a trivially-copyable"
   " type (%0 invalid)">;

lib/Sema/SemaChecking.cpp

diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index 0e6b5ec..6d8d7f2 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -742,6 +742,11 @@
         << Ptr->getType() << Ptr->getSourceRange();
       return ExprError();
     }
+    if (AtomTy.isConstQualified()) {
+      Diag(DRE->getLocStart(), diag::err_atomic_op_needs_non_const_atomic)
+        << Ptr->getType() << Ptr->getSourceRange();
+      return ExprError();
+    }
     ValType = AtomTy->getAs<AtomicType>()->getValueType();
   }
 
@@ -6124,4 +6129,3 @@
         << ArgumentExpr->getSourceRange()
         << TypeTagExpr->getSourceRange();
 }
-

test/Sema/atomic-ops.c

diff --git a/test/Sema/atomic-ops.c b/test/Sema/atomic-ops.c
index f769271..2a93591 100644
--- a/test/Sema/atomic-ops.c
+++ b/test/Sema/atomic-ops.c
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 %s -verify -fsyntax-only -triple=i686-linux-gnu
+// RUN: %clang_cc1 %s -verify -fsyntax-only -triple=i686-linux-gnu -std=c11
 
 // Basic parsing/Sema tests for __c11_atomic_*
 
@@ -162,4 +162,9 @@
   __atomic_clear(&flag_k, memory_order_seq_cst); // expected-warning {{passing 'const volatile int *' to parameter of type 'volatile void *'}}
   __atomic_clear(&flag, memory_order_seq_cst);
   (int)__atomic_clear(&flag, memory_order_seq_cst); // expected-error {{operand of type 'void'}}
+
+  const _Atomic(int) const_atomic;
+  __c11_atomic_init(&const_atomic, 0); // expected-error {{first argument to atomic operation must be a pointer to non-const _Atomic type ('const _Atomic(int) *' invalid)}}
+  __c11_atomic_store(&const_atomic, 0, memory_order_release); // expected-error {{first argument to atomic operation must be a pointer to non-const _Atomic type ('const _Atomic(int) *' invalid)}}
+  __c11_atomic_load(&const_atomic, memory_order_acquire); // expected-error {{first argument to atomic operation must be a pointer to non-const _Atomic type ('const _Atomic(int) *' invalid)}}
 }