// RUN: rm -rf %t // RUN: split-file %s %t // RUN: %clang_cc1 -fmodules -fimplicit-module-maps -fmodules-cache-path=%t/no-lsv -I%t %t/stddef.cpp -verify // RUN: %clang_cc1 -fmodules -fimplicit-module-maps -fmodules-local-submodule-visibility -fmodules-cache-path=%t/lsv -I%t %t/stddef.cpp -verify //--- stddef.cpp #include void *pointer = NULL; size_t size = 0; // When building with modules, a pcm is never re-imported, so re-including // stddef.h will not re-import _Builtin_stddef.null to restore the definition of // NULL, even though stddef.h will unconditionally include __stddef_null.h when // building with modules. #undef NULL #include void *anotherPointer = NULL; // expected-error{{use of undeclared identifier 'NULL'}} // stddef.h needs to be a `textual` header to support clients doing things like // this. // // #define __need_NULL // #include // // As a textual header designed to be included multiple times, it can't directly // declare anything, or those declarations would go into every module that // included it. e.g. if stddef.h contained all of its declarations, and modules // A and B included stddef.h, they would both have the declaration for size_t. // That breaks Swift, which uses the module name as part of the type name, i.e. // A.size_t and B.size_t are treated as completely different types in Swift and // cannot be interchanged. To fix that, stddef.h (and stdarg.h) are split out // into a separate file per __need macro that can be normal headers in explicit // submodules. That runs into yet another wrinkle though. When modules build, // declarations from previous submodules leak into subsequent ones when not // using local submodule visibility. Consider if stddef.h did the normal thing. // // #ifndef __STDDEF_H // #define __STDDEF_H // // include all of the sub-headers // #endif // // When SM builds without local submodule visibility, it will precompile a.h // first. When it gets to b.h, the __STDDEF_H declaration from precompiling a.h // will leak, and so when b.h includes stddef.h, it won't include any of its // sub-headers, and SM.B will thus not import _Builtin_stddef or make any of its // submodules visible. Precompiling b.h will be fine since it sees all of the // declarations from a.h including stddef.h, but clients that only include b.h // will not see any of the stddef.h types. stddef.h thus has to make sure to // always include the necessary sub-headers, even if they've been included // already. They all have their own header guards to allow this. // __stddef_null.h is extra special, so this test makes sure to cover NULL plus // one of the normal stddef.h types. //--- module.modulemap module SM { module A { header "a.h" export * } module B { header "b.h" export * } } //--- a.h #include //--- b.h #include