Diagnose const atomics in __atomic builtins.

Diagnose when a pointer to const T is used as the first argument in at atomic
builtin unless that builtin is a load operation. This is already checked for
C11 atomics builtins but not for __atomic ones.

This patch was given the LGTM by rsmith when it was part
of a larger review. (See http://reviews.llvm.org/D10407)

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@249252 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index fa1a6ff8fc5a8398a1d556064e2186ff55c10eca..584d734bf34826a058cbd851f0c47adfc7c61a31 100644 (file)
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -6202,6 +6202,9 @@ def err_atomic_op_needs_atomic : Error<
 def err_atomic_op_needs_non_const_atomic : Error<
   "address argument to atomic operation must be a pointer to non-const _Atomic "
   "type (%0 invalid)">;
+def err_atomic_op_needs_non_const_pointer : Error<
+  "address argument to atomic operation must be a pointer to non-const "
+  "type (%0 invalid)">;
 def err_atomic_op_needs_trivial_copy : Error<
   "address argument to atomic operation must be a pointer to a "
   "trivially-copyable type (%0 invalid)">;

diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index ae7f6d6a803bb5ecafcf45862f8b086596256e00..599a0e4be214626f91dd6dcd01660d9a329ad633 100644 (file)
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -1644,6 +1644,12 @@ ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult,
       return ExprError();
     }
     ValType = AtomTy->getAs<AtomicType>()->getValueType();
+  } else if (Form != Load && Op != AtomicExpr::AO__atomic_load) {
+    if (ValType.isConstQualified()) {
+      Diag(DRE->getLocStart(), diag::err_atomic_op_needs_non_const_pointer)
+        << Ptr->getType() << Ptr->getSourceRange();
+      return ExprError();
+    }
   }
 
   // For an arithmetic operation, the implied arithmetic must be well-formed.
@@ -1681,9 +1687,6 @@ ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult,
     return ExprError();
   }
 
-  // FIXME: For any builtin other than a load, the ValType must not be
-  // const-qualified.
-
   switch (ValType.getObjCLifetime()) {
   case Qualifiers::OCL_None:
   case Qualifiers::OCL_ExplicitNone:
@@ -1716,6 +1719,10 @@ ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult,
   if (!IsC11 && !IsN)
     ByValType = Ptr->getType();
 
+  // FIXME: __atomic_load allows the first argument to be a a pointer to const
+  // but not the second argument. We need to manually remove possible const
+  // qualifiers.
+
   // The first argument --- the pointer --- has a fixed type; we
   // deduce the types of the rest of the arguments accordingly.  Walk
   // the remaining arguments, converting them to the deduced value type.

diff --git a/test/Sema/atomic-ops.c b/test/Sema/atomic-ops.c
index 71eaaa8b7a5b0ecd9ffbb96806a54b4d3d8ec8bd..5f308be7b46ab9248198f28e0b8df861f196a301 100644 (file)
--- a/test/Sema/atomic-ops.c
+++ b/test/Sema/atomic-ops.c
@@ -85,41 +85,54 @@ _Static_assert(__atomic_always_lock_free(4, &i64), "");
 _Static_assert(!__atomic_always_lock_free(8, &i32), "");
 _Static_assert(__atomic_always_lock_free(8, &i64), "");
 
-void f(_Atomic(int) *i, _Atomic(int*) *p, _Atomic(float) *d,
-       int *I, int **P, float *D, struct S *s1, struct S *s2) {
+void f(_Atomic(int) *i, const _Atomic(int) *ci,
+       _Atomic(int*) *p, _Atomic(float) *d,
+       int *I, const int *CI,
+       int **P, float *D, struct S *s1, struct S *s2) {
   __c11_atomic_init(I, 5); // expected-error {{pointer to _Atomic}}
+  __c11_atomic_init(ci, 5); // expected-error {{address argument to atomic operation must be a pointer to non-const _Atomic type ('const _Atomic(int) *' invalid)}}
+
   __c11_atomic_load(0); // expected-error {{too few arguments to function}}
   __c11_atomic_load(0,0,0); // expected-error {{too many arguments to function}}
   __c11_atomic_store(0,0,0); // expected-error {{address argument to atomic builtin must be a pointer}}
   __c11_atomic_store((int*)0,0,0); // expected-error {{address argument to atomic operation must be a pointer to _Atomic}}
+  __c11_atomic_store(i, 0, memory_order_relaxed);
+  __c11_atomic_store(ci, 0, memory_order_relaxed); // expected-error {{address argument to atomic operation must be a pointer to non-const _Atomic type ('const _Atomic(int) *' invalid)}}
 
   __c11_atomic_load(i, memory_order_seq_cst);
   __c11_atomic_load(p, memory_order_seq_cst);
   __c11_atomic_load(d, memory_order_seq_cst);
+  __c11_atomic_load(ci, memory_order_seq_cst); // expected-error {{address argument to atomic operation must be a pointer to non-const _Atomic type ('const _Atomic(int) *' invalid)}}
 
   int load_n_1 = __atomic_load_n(I, memory_order_relaxed);
   int *load_n_2 = __atomic_load_n(P, memory_order_relaxed);
   float load_n_3 = __atomic_load_n(D, memory_order_relaxed); // expected-error {{must be a pointer to integer or pointer}}
   __atomic_load_n(s1, memory_order_relaxed); // expected-error {{must be a pointer to integer or pointer}}
+  load_n_1 = __atomic_load_n(CI, memory_order_relaxed);
 
   __atomic_load(i, I, memory_order_relaxed); // expected-error {{must be a pointer to a trivially-copyable type}}
+  __atomic_load(CI, I, memory_order_relaxed);
+
   __atomic_load(I, i, memory_order_relaxed); // expected-warning {{passing '_Atomic(int) *' to parameter of type 'int *'}}
   __atomic_load(I, *P, memory_order_relaxed);
   __atomic_load(I, *P, memory_order_relaxed, 42); // expected-error {{too many arguments}}
   (int)__atomic_load(I, I, memory_order_seq_cst); // expected-error {{operand of type 'void'}}
   __atomic_load(s1, s2, memory_order_acquire);
-
+  (void)__atomic_load(I, CI, memory_order_relaxed); // expected-warning {{passing 'const int *' to parameter of type 'int *' discards qualifiers}}
   __c11_atomic_store(i, 1, memory_order_seq_cst);
   __c11_atomic_store(p, 1, memory_order_seq_cst); // expected-warning {{incompatible integer to pointer conversion}}
   (int)__c11_atomic_store(d, 1, memory_order_seq_cst); // expected-error {{operand of type 'void'}}
 
   __atomic_store_n(I, 4, memory_order_release);
   __atomic_store_n(I, 4.0, memory_order_release);
+  __atomic_store_n(CI, 4, memory_order_release); // expected-error {{address argument to atomic operation must be a pointer to non-const type ('const int *' invalid)}}
   __atomic_store_n(I, P, memory_order_release); // expected-warning {{parameter of type 'int'}}
   __atomic_store_n(i, 1, memory_order_release); // expected-error {{must be a pointer to integer or pointer}}
   __atomic_store_n(s1, *s2, memory_order_release); // expected-error {{must be a pointer to integer or pointer}}
+  __atomic_store_n(I, I, memory_order_release); // expected-warning {{incompatible pointer to integer conversion passing 'int *' to parameter of type 'int'; dereference with *}}
 
   __atomic_store(I, *P, memory_order_release);
+  __atomic_store(CI, I, memory_order_release); // expected-error {{address argument to atomic operation must be a pointer to non-const type ('const int *' invalid)}}
   __atomic_store(s1, s2, memory_order_release);
   __atomic_store(i, I, memory_order_release); // expected-error {{trivially-copyable}}
 
@@ -131,6 +144,9 @@ void f(_Atomic(int) *i, _Atomic(int*) *p, _Atomic(float) *d,
   __atomic_exchange(s1, s2, s2, memory_order_seq_cst);
   __atomic_exchange(s1, I, P, memory_order_seq_cst); // expected-warning 2{{parameter of type 'struct S *'}}
   (int)__atomic_exchange(s1, s2, s2, memory_order_seq_cst); // expected-error {{operand of type 'void'}}
+  __atomic_exchange(I, I, I, memory_order_seq_cst);
+  __atomic_exchange(CI, I, I, memory_order_seq_cst); // expected-error {{address argument to atomic operation must be a pointer to non-const type ('const int *' invalid)}}
+  __atomic_exchange(I, I, CI, memory_order_seq_cst); // expected-warning {{passing 'const int *' to parameter of type 'int *' discards qualifiers}}
 
   __c11_atomic_fetch_add(i, 1, memory_order_seq_cst);
   __c11_atomic_fetch_add(p, 1, memory_order_seq_cst);
@@ -155,14 +171,24 @@ void f(_Atomic(int) *i, _Atomic(int*) *p, _Atomic(float) *d,
   _Bool cmpexch_1 = __c11_atomic_compare_exchange_strong(i, 0, 1, memory_order_seq_cst, memory_order_seq_cst);
   _Bool cmpexch_2 = __c11_atomic_compare_exchange_strong(p, 0, (int*)1, memory_order_seq_cst, memory_order_seq_cst);
   _Bool cmpexch_3 = __c11_atomic_compare_exchange_strong(d, (int*)0, 1, memory_order_seq_cst, memory_order_seq_cst); // expected-warning {{incompatible pointer types}}
+  (void)__c11_atomic_compare_exchange_strong(i, CI, 1, memory_order_seq_cst, memory_order_seq_cst); // expected-warning {{passing 'const int *' to parameter of type 'int *' discards qualifiers}}
+
+  _Bool cmpexchw_1 = __c11_atomic_compare_exchange_weak(i, 0, 1, memory_order_seq_cst, memory_order_seq_cst);
+  _Bool cmpexchw_2 = __c11_atomic_compare_exchange_weak(p, 0, (int*)1, memory_order_seq_cst, memory_order_seq_cst);
+  _Bool cmpexchw_3 = __c11_atomic_compare_exchange_weak(d, (int*)0, 1, memory_order_seq_cst, memory_order_seq_cst); // expected-warning {{incompatible pointer types}}
+  (void)__c11_atomic_compare_exchange_weak(i, CI, 1, memory_order_seq_cst, memory_order_seq_cst); // expected-warning {{passing 'const int *' to parameter of type 'int *' discards qualifiers}}
 
   _Bool cmpexch_4 = __atomic_compare_exchange_n(I, I, 5, 1, memory_order_seq_cst, memory_order_seq_cst);
   _Bool cmpexch_5 = __atomic_compare_exchange_n(I, P, 5, 0, memory_order_seq_cst, memory_order_seq_cst); // expected-warning {{; dereference with *}}
   _Bool cmpexch_6 = __atomic_compare_exchange_n(I, I, P, 0, memory_order_seq_cst, memory_order_seq_cst); // expected-warning {{passing 'int **' to parameter of type 'int'}}
+  (void)__atomic_compare_exchange_n(CI, I, 5, 1, memory_order_seq_cst, memory_order_seq_cst); // expected-error {{address argument to atomic operation must be a pointer to non-const type ('const int *' invalid)}}
+  (void)__atomic_compare_exchange_n(I, CI, 5, 1, memory_order_seq_cst, memory_order_seq_cst); // expected-warning {{passing 'const int *' to parameter of type 'int *' discards qualifiers}}
 
   _Bool cmpexch_7 = __atomic_compare_exchange(I, I, 5, 1, memory_order_seq_cst, memory_order_seq_cst); // expected-warning {{passing 'int' to parameter of type 'int *'}}
   _Bool cmpexch_8 = __atomic_compare_exchange(I, P, I, 0, memory_order_seq_cst, memory_order_seq_cst); // expected-warning {{; dereference with *}}
   _Bool cmpexch_9 = __atomic_compare_exchange(I, I, I, 0, memory_order_seq_cst, memory_order_seq_cst);
+  (void)__atomic_compare_exchange(CI, I, I, 0, memory_order_seq_cst, memory_order_seq_cst); // expected-error {{address argument to atomic operation must be a pointer to non-const type ('const int *' invalid)}}
+  (void)__atomic_compare_exchange(I, CI, I, 0, memory_order_seq_cst, memory_order_seq_cst); // expected-warning {{passing 'const int *' to parameter of type 'int *' discards qualifiers}}
 
   const volatile int flag_k = 0;
   volatile int flag = 0;
@@ -172,10 +198,9 @@ void f(_Atomic(int) *i, _Atomic(int*) *p, _Atomic(float) *d,
   __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 {{address 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 {{address 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 {{address argument to atomic operation must be a pointer to non-const _Atomic type ('const _Atomic(int) *' invalid)}}
+  __c11_atomic_init(ci, 0); // expected-error {{address argument to atomic operation must be a pointer to non-const _Atomic type ('const _Atomic(int) *' invalid)}}
+  __c11_atomic_store(ci, 0, memory_order_release); // expected-error {{address argument to atomic operation must be a pointer to non-const _Atomic type ('const _Atomic(int) *' invalid)}}
+  __c11_atomic_load(ci, memory_order_acquire); // expected-error {{address argument to atomic operation must be a pointer to non-const _Atomic type ('const _Atomic(int) *' invalid)}}
 
   // Ensure the <stdatomic.h> macros behave appropriately.
   atomic_int n = ATOMIC_VAR_INIT(123);