manmanren created this revision.
manmanren added reviewers: rjmccall, Anastasia.
manmanren added a subscriber: cfe-commits.
A simple example will crash at IRGen:
void (^simpleBlock)() = ^ _Nonnull {
return;
};
The Return type for the block will be AttributedType of a DependentTy and it
will not be resolved. We will get a crash at IRGen.
The fix is to warn when we have type attributes or qualifiers with omitted
return type. The type attributes and qualifiers will be ignored.
This breaks test/SemaOpenCL/invalid-block.cl where it uses "^const(){}".
"int (^const bl3)() = ^const(){};" should emit error since we are converting
between incompatible block pointer types, the block literal's return type
should be void.
http://reviews.llvm.org/D18567
Files:
include/clang/Basic/DiagnosticSemaKinds.td
lib/Sema/SemaType.cpp
test/SemaObjC/block-omitted-return-type.m
test/SemaOpenCL/invalid-block.cl
Index: test/SemaObjC/block-omitted-return-type.m
===================================================================
--- /dev/null
+++ test/SemaObjC/block-omitted-return-type.m
@@ -0,0 +1,33 @@
+// RUN: %clang_cc1 %s -fblocks -verify -fsyntax-only
+
+@interface NSObject
+@end
+
+@interface Test : NSObject
+- (void)test;
+@end
+
+@implementation Test
+- (void)test
+{
+ void (^simpleBlock)() = ^ _Nonnull { //expected-warning {{attribute '_Nonnull' ignored, because it cannot be applied to omitted return type}}
+ return;
+ };
+ void (^simpleBlock2)() = ^ _Nonnull void { //expected-error {{nullability specifier '_Nonnull' cannot be applied to non-pointer type 'void'}}
+ return;
+ };
+ void (^simpleBlock3)() = ^ _Nonnull (void) { //expected-warning {{attribute '_Nonnull' ignored, because it cannot be applied to omitted return type}}
+ return;
+ };
+
+ void (^simpleBlock4)() = ^ const { //expected-warning {{'const' qualifier on omitted return type '<dependent type>' has no effect}}
+ return;
+ };
+ void (^simpleBlock5)() = ^ const void { //expected-error {{incompatible block pointer types initializing 'void (^)()' with an expression of type 'const void (^)(void)'}}
+ return;
+ };
+ void (^simpleBlock6)() = ^ const (void) { //expected-warning {{'const' qualifier on omitted return type '<dependent type>' has no effect}}
+ return;
+ };
+}
+@end
Index: test/SemaOpenCL/invalid-block.cl
===================================================================
--- test/SemaOpenCL/invalid-block.cl
+++ test/SemaOpenCL/invalid-block.cl
@@ -6,14 +6,14 @@
void f1() {
int (^bl1)() = ^() {}; // expected-error{{invalid block variable declaration - must be const qualified}}
int (^const bl2)(); // expected-error{{invalid block variable declaration - must be initialized}}
- int (^const bl3)() = ^const(){
+ int (^const bl3)() = ^(){ // expected-error{{incompatible block pointer types initializing 'int (^const)()' with an expression of type 'void (^)(void)'}}
};
}
// A block with extern storage class is not allowed.
-extern int (^const bl)() = ^const(){}; // expected-error{{invalid block variable declaration - using 'extern' storage class is disallowed}}
+extern int (^const bl)() = ^(){}; // expected-error{{invalid block variable declaration - using 'extern' storage class is disallowed}}
void f2() {
- extern int (^const bl)() = ^const(){}; // expected-error{{invalid block variable declaration - using 'extern' storage class is disallowed}}
+ extern int (^const bl)() = ^(){}; // expected-error{{invalid block variable declaration - using 'extern' storage class is disallowed}}
}
// A block cannot be the return value of a function.
@@ -36,15 +36,15 @@
// A block can't be used to declare an array
typedef int (^const bl1_t)(int);
void f5(int i) {
- bl1_t bl1 = ^const(int i) {return 1;};
- bl1_t bl2 = ^const(int i) {return 2;};
+ bl1_t bl1 = ^(int i) {return 1;};
+ bl1_t bl2 = ^(int i) {return 2;};
bl1_t arr[] = {bl1, bl2}; // expected-error {{array of 'bl1_t' (aka 'int (^const)(int)') type is invalid in OpenCL}}
int tmp = i ? bl1(i) // expected-error {{block type cannot be used as expression in ternary expression in OpenCL}}
: bl2(i); // expected-error {{block type cannot be used as expression in ternary expression in OpenCL}}
}
void f6(bl1_t * bl_ptr) {
- bl1_t bl = ^const(int i) {return 1;};
+ bl1_t bl = ^(int i) {return 1;};
bl1_t *p = &bl; // expected-error {{invalid argument type 'bl1_t' (aka 'int (^const)(int)') to unary expression}}
bl = *bl_ptr; // expected-error {{dereferencing pointer of type '__generic bl1_t *' (aka 'int (^const __generic *)(int)') is not allowed in OpenCL}}
}
Index: lib/Sema/SemaType.cpp
===================================================================
--- lib/Sema/SemaType.cpp
+++ lib/Sema/SemaType.cpp
@@ -1552,6 +1552,25 @@
break;
}
+ // Warn if we see type attributes for omitted return type on a block literal.
+ if (isOmittedBlockReturnType(declarator)) {
+ if (auto *attrs = DS.getAttributes().getList()) {
+ while (attrs) {
+ AttributeList &attr = *attrs;
+ attrs = attr.getNext();
+ // Skip attributes that were marked to be invalid or non-type
+ // attributes.
+ if (attr.isInvalid() || !attr.isTypeAttr())
+ continue;
+ S.Diag(attr.getLoc(),
+ diag::warn_block_literal_attributes_on_omitted_return_type)
+ << attr.getName();
+ // Mark them as invalid.
+ attr.setInvalid();
+ }
+ }
+ }
+
// Handle complex types.
if (DS.getTypeSpecComplex() == DeclSpec::TSC_complex) {
if (S.getLangOpts().Freestanding)
@@ -1586,6 +1605,13 @@
// Apply const/volatile/restrict qualifiers to T.
if (unsigned TypeQuals = DS.getTypeQualifiers()) {
+ // Warn if we see type qualifiers for omitted return type on a block literal.
+ if (TypeQuals && isOmittedBlockReturnType(declarator)) {
+ diagnoseAndRemoveTypeQualifiers(S, DS, TypeQuals, Result,
+ DeclSpec::TQ_const | DeclSpec::TQ_volatile | DeclSpec::TQ_atomic,
+ diag::warn_block_literal_qualifiers_on_omitted_return_type);
+ }
+
// Warn about CV qualifiers on function types.
// C99 6.7.3p8:
// If the specification of a function type includes any type qualifiers,
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -8386,4 +8386,12 @@
"parameterized class %0 already conforms to the protocols listed; did you "
"forget a '*'?">, InGroup<ObjCProtocolQualifiers>;
+def warn_block_literal_attributes_on_omitted_return_type : Warning<
+ "attribute %0 ignored, because it cannot be applied to omitted return type">,
+ InGroup<IgnoredAttributes>;
+
+def warn_block_literal_qualifiers_on_omitted_return_type : Warning<
+ "'%0' qualifier on omitted return type %1 has no effect">,
+ InGroup<IgnoredQualifiers>;
+
} // end of sema component.
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