r333246 - Make atomic non-member functions as nonnull
JF Bastien via cfe-commits
cfe-commits at lists.llvm.org
Thu May 24 17:07:09 PDT 2018
Author: jfb
Date: Thu May 24 17:07:09 2018
New Revision: 333246
URL: http://llvm.org/viewvc/llvm-project?rev=333246&view=rev
Log:
Make atomic non-member functions as nonnull
Summary:
As a companion to libc++ patch https://reviews.llvm.org/D47225, mark builtin atomic non-member functions which accept pointers as nonnull.
The atomic non-member functions accept pointers to std::atomic / std::atomic_flag as well as to the non-atomic value. These are all dereferenced unconditionally when lowered, and therefore will fault if null. It's a tiny gotcha for new users, especially when they pass in NULL as expected value (instead of passing a pointer to a NULL value).
<rdar://problem/18473124>
Reviewers: arphaman
Subscribers: aheejin, cfe-commits
Differential Revision: https://reviews.llvm.org/D47229
Modified:
cfe/trunk/lib/Sema/SemaChecking.cpp
cfe/trunk/test/Sema/atomic-ops.c
Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=333246&r1=333245&r2=333246&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
+++ cfe/trunk/lib/Sema/SemaChecking.cpp Thu May 24 17:07:09 2018
@@ -3451,9 +3451,10 @@ ExprResult Sema::SemaAtomicOpsOverloaded
return ExprError();
}
- // atomic_fetch_or takes a pointer to a volatile 'A'. We shouldn't let the
- // volatile-ness of the pointee-type inject itself into the result or the
- // other operands. Similarly atomic_load can take a pointer to a const 'A'.
+ // All atomic operations have an overload which takes a pointer to a volatile
+ // 'A'. We shouldn't let the volatile-ness of the pointee-type inject itself
+ // into the result or the other operands. Similarly atomic_load takes a
+ // pointer to a const 'A'.
ValType.removeLocalVolatile();
ValType.removeLocalConst();
QualType ResultType = ValType;
@@ -3466,16 +3467,27 @@ ExprResult Sema::SemaAtomicOpsOverloaded
// The type of a parameter passed 'by value'. In the GNU atomics, such
// arguments are actually passed as pointers.
QualType ByValType = ValType; // 'CP'
- if (!IsC11 && !IsN)
+ bool IsPassedByAddress = false;
+ if (!IsC11 && !IsN) {
ByValType = Ptr->getType();
+ IsPassedByAddress = true;
+ }
- // 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.
- for (unsigned i = 1; i != TheCall->getNumArgs(); ++i) {
+ // The first argument's non-CV pointer type is used to deduce the type of
+ // subsequent arguments, except for:
+ // - weak flag (always converted to bool)
+ // - memory order (always converted to int)
+ // - scope (always converted to int)
+ for (unsigned i = 0; i != TheCall->getNumArgs(); ++i) {
QualType Ty;
if (i < NumVals[Form] + 1) {
switch (i) {
+ case 0:
+ // The first argument is always a pointer. It has a fixed type.
+ // It is always dereferenced, a nullptr is undefined.
+ CheckNonNullArgument(*this, TheCall->getArg(i), DRE->getLocStart());
+ // Nothing else to do: we already know all we want about this pointer.
+ continue;
case 1:
// The second argument is the non-atomic operand. For arithmetic, this
// is always passed by value, and for a compare_exchange it is always
@@ -3484,14 +3496,16 @@ ExprResult Sema::SemaAtomicOpsOverloaded
assert(Form != Load);
if (Form == Init || (Form == Arithmetic && ValType->isIntegerType()))
Ty = ValType;
- else if (Form == Copy || Form == Xchg)
+ else if (Form == Copy || Form == Xchg) {
+ if (IsPassedByAddress)
+ // The value pointer is always dereferenced, a nullptr is undefined.
+ CheckNonNullArgument(*this, TheCall->getArg(i), DRE->getLocStart());
Ty = ByValType;
- else if (Form == Arithmetic)
+ } else if (Form == Arithmetic)
Ty = Context.getPointerDiffType();
else {
Expr *ValArg = TheCall->getArg(i);
- // Treat this argument as _Nonnull as we want to show a warning if
- // NULL is passed into it.
+ // The value pointer is always dereferenced, a nullptr is undefined.
CheckNonNullArgument(*this, ValArg, DRE->getLocStart());
LangAS AS = LangAS::Default;
// Keep address space of non-atomic pointer type.
@@ -3504,8 +3518,10 @@ ExprResult Sema::SemaAtomicOpsOverloaded
}
break;
case 2:
- // The third argument to compare_exchange / GNU exchange is a
- // (pointer to a) desired value.
+ // The third argument to compare_exchange / GNU exchange is the desired
+ // value, either by-value (for the *_n variant) or as a pointer.
+ if (!IsN)
+ CheckNonNullArgument(*this, TheCall->getArg(i), DRE->getLocStart());
Ty = ByValType;
break;
case 3:
@@ -3887,7 +3903,7 @@ Sema::SemaBuiltinAtomicOverloaded(ExprRe
ResultType = Context.BoolTy;
break;
- case Builtin::BI__sync_lock_test_and_set:
+ case Builtin::BI__sync_lock_test_and_set:
case Builtin::BI__sync_lock_test_and_set_1:
case Builtin::BI__sync_lock_test_and_set_2:
case Builtin::BI__sync_lock_test_and_set_4:
Modified: cfe/trunk/test/Sema/atomic-ops.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/atomic-ops.c?rev=333246&r1=333245&r2=333246&view=diff
==============================================================================
--- cfe/trunk/test/Sema/atomic-ops.c (original)
+++ cfe/trunk/test/Sema/atomic-ops.c Thu May 24 17:07:09 2018
@@ -531,8 +531,80 @@ void memory_checks(_Atomic(int) *Ap, int
}
void nullPointerWarning(_Atomic(int) *Ap, int *p, int val) {
- // The 'expected' pointer shouldn't be NULL.
- (void)__c11_atomic_compare_exchange_strong(Ap, NULL, val, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
- (void)atomic_compare_exchange_weak(Ap, ((void*)0), val); // expected-warning {{null passed to a callee that requires a non-null argument}}
- (void)__atomic_compare_exchange_n(p, NULL, val, 0, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ volatile _Atomic(int) vai;
+ _Atomic(int) ai;
+ volatile int vi = 42;
+ int i = 42;
+
+ __c11_atomic_init((volatile _Atomic(int)*)0, 42); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ __c11_atomic_init((_Atomic(int)*)0, 42); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ __c11_atomic_store((volatile _Atomic(int)*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ __c11_atomic_store((_Atomic(int)*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_load((volatile _Atomic(int)*)0, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_load((_Atomic(int)*)0, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_exchange((volatile _Atomic(int)*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_exchange((_Atomic(int)*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_compare_exchange_weak((volatile _Atomic(int)*)0, &i, 42, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_compare_exchange_weak((_Atomic(int)*)0, &i, 42, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_compare_exchange_weak(&vai, (int*)0, 42, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_compare_exchange_weak(&ai, (int*)0, 42, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_compare_exchange_strong((volatile _Atomic(int)*)0, &i, 42, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_compare_exchange_strong((_Atomic(int)*)0, &i, 42, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_compare_exchange_strong(&vai, (int*)0, 42, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_compare_exchange_strong(&ai, (int*)0, 42, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_fetch_add((volatile _Atomic(int)*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_fetch_add((_Atomic(int)*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_fetch_sub((volatile _Atomic(int)*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_fetch_sub((_Atomic(int)*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_fetch_and((volatile _Atomic(int)*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_fetch_and((_Atomic(int)*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_fetch_or((volatile _Atomic(int)*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_fetch_or((_Atomic(int)*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_fetch_xor((volatile _Atomic(int)*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__c11_atomic_fetch_xor((_Atomic(int)*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+
+ __atomic_store_n((volatile int*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ __atomic_store_n((int*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ __atomic_store((volatile int*)0, &i, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ __atomic_store((int*)0, &i, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ __atomic_store(&vi, (int*)0, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ __atomic_store(&i, (int*)0, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_load_n((volatile int*)0, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_load_n((int*)0, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ __atomic_load((volatile int*)0, &i, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ __atomic_load((int*)0, &i, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ __atomic_load(&vi, (int*)0, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ __atomic_load(&i, (int*)0, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_exchange_n((volatile int*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_exchange_n((int*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ __atomic_exchange((volatile int*)0, &i, &i, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ __atomic_exchange((int*)0, &i, &i, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ __atomic_exchange(&vi, (int*)0, &i, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ __atomic_exchange(&i, (int*)0, &i, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ __atomic_exchange(&vi, &i, (int*)0, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ __atomic_exchange(&i, &i, (int*)0, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_compare_exchange_n((volatile int*)0, &i, 42, /*weak=*/0, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_compare_exchange_n((int*)0, &i, 42, /*weak=*/0, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_compare_exchange_n(&vi, (int*)0, 42, /*weak=*/0, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_compare_exchange_n(&i, (int*)0, 42, /*weak=*/0, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_compare_exchange((volatile int*)0, &i, &i, /*weak=*/0, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_compare_exchange((int*)0, &i, &i, /*weak=*/0, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_compare_exchange(&vi, (int*)0, &i, /*weak=*/0, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_compare_exchange(&i, (int*)0, &i, /*weak=*/0, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_compare_exchange(&vi, &i, (int*)0, /*weak=*/0, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_compare_exchange(&i, &i, (int*)0, /*weak=*/0, memory_order_relaxed, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_fetch_add((volatile int*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_fetch_add((int*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_fetch_sub((volatile int*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_fetch_sub((int*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_fetch_and((volatile int*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_fetch_and((int*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_fetch_or((volatile int*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_fetch_or((int*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_fetch_xor((volatile int*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_fetch_xor((int*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_fetch_min((volatile int*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_fetch_min((int*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_fetch_max((volatile int*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
+ (void)__atomic_fetch_max((int*)0, 42, memory_order_relaxed); // expected-warning {{null passed to a callee that requires a non-null argument}}
}
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