7d644e1215
C89 had a questionable feature where the compiler would implicitly declare a function that the user called but was never previously declared. The resulting function would be globally declared as extern int func(); -- a function without a prototype which accepts zero or more arguments. C99 removed support for this questionable feature due to severe security concerns. However, there was no deprecation period; C89 had the feature, C99 didn't. So Clang (and GCC) both supported the functionality as an extension in C99 and later modes. C2x no longer supports that function signature as it now requires all functions to have a prototype, and given the known security issues with the feature, continuing to support it as an extension is not tenable. This patch changes the diagnostic behavior for the -Wimplicit-function-declaration warning group depending on the language mode in effect. We continue to warn by default in C89 mode (due to the feature being dangerous to use). However, because this feature will not be supported in C2x mode, we've diagnosed it as being invalid for so long, the security concerns with the feature, and the trivial workaround for users (declare the function), we now default the extension warning to an error in C99-C17 mode. This still gives users an easy workaround if they are extensively using the extension in those modes (they can disable the warning or use -Wno-error to downgrade the error), but the new diagnostic makes it more clear that this feature is not supported and should be avoided. In C2x mode, we no longer allow an implicit function to be defined and treat the situation the same as any other lookup failure. Differential Revision: https://reviews.llvm.org/D122983
30 lines
2.3 KiB
Objective-C
30 lines
2.3 KiB
Objective-C
// RUN: %clang_cc1 -x objective-c %s -fsyntax-only -verify
|
|
// rdar://8592641
|
|
Class f0(void) { return objc_getClass("a"); } // expected-error {{call to undeclared library function 'objc_getClass' with type 'id (const char *)'}} \
|
|
// expected-note {{include the header <objc/runtime.h> or explicitly provide a declaration for 'objc_getClass'}}
|
|
|
|
// rdar://8735023
|
|
Class f1(void) { return objc_getMetaClass("a"); } // expected-error {{call to undeclared library function 'objc_getMetaClass' with type 'id (const char *)'}} \
|
|
// expected-note {{include the header <objc/runtime.h> or explicitly provide a declaration for 'objc_getMetaClass'}}
|
|
|
|
void f2(id val) { objc_enumerationMutation(val); } // expected-error {{call to undeclared library function 'objc_enumerationMutation' with type 'void (id)'}} \
|
|
// expected-note {{include the header <objc/runtime.h> or explicitly provide a declaration for 'objc_enumerationMutation'}}
|
|
|
|
long double f3(id self, SEL op) { return objc_msgSend_fpret(self, op); } // expected-error {{call to undeclared library function 'objc_msgSend_fpret' with type 'long double (id, SEL, ...)'}} \
|
|
// expected-note {{include the header <objc/message.h> or explicitly provide a declaration for 'objc_msgSend_fpret'}}
|
|
|
|
id f4(struct objc_super *super, SEL op) { // expected-warning {{declaration of 'struct objc_super' will not be visible outside of this function}}
|
|
return objc_msgSendSuper(super, op); // expected-error {{call to undeclared library function 'objc_msgSendSuper' with type 'id (struct objc_super *, SEL, ...)'}} \
|
|
// expected-note {{include the header <objc/message.h> or explicitly provide a declaration for 'objc_msgSendSuper'}}
|
|
}
|
|
|
|
id f5(id val, id *dest) {
|
|
return objc_assign_strongCast(val, dest); // expected-error {{call to undeclared library function 'objc_assign_strongCast' with type 'id (id, id *)'}} \
|
|
// expected-note {{include the header <objc/objc-auto.h> or explicitly provide a declaration for 'objc_assign_strongCast'}}
|
|
}
|
|
|
|
int f6(Class exceptionClass, id exception) {
|
|
return objc_exception_match(exceptionClass, exception); // expected-error {{call to undeclared library function 'objc_exception_match' with type 'int (id, id)'}} \
|
|
// expected-note {{include the header <objc/objc-exception.h> or explicitly provide a declaration for 'objc_exception_match'}}
|
|
}
|