diff --git a/MdePkg/Include/Base.h b/MdePkg/Include/Base.h index 89b2aed072..cbd9e552d0 100644 --- a/MdePkg/Include/Base.h +++ b/MdePkg/Include/Base.h @@ -84,6 +84,116 @@ VERIFY_SIZE_OF (CHAR16, 2); #define GLOBAL_REMOVE_IF_UNREFERENCED #endif +// +// Should be used in combination with NORETURN to avoid 'noreturn' returns +// warnings. +// +#ifndef UNREACHABLE + #ifdef __GNUC__ + /// + /// Signal compilers and analyzers that this call is not reachable. It is + /// up to the compiler to remove any code past that point. + /// + #define UNREACHABLE() __builtin_unreachable () + #elif defined (__has_feature) + #if __has_builtin (__builtin_unreachable) + /// + /// Signal compilers and analyzers that this call is not reachable. It is + /// up to the compiler to remove any code past that point. + /// + #define UNREACHABLE() __builtin_unreachable () + #endif + #endif + + #ifndef UNREACHABLE + /// + /// Signal compilers and analyzers that this call is not reachable. It is + /// up to the compiler to remove any code past that point. + /// + #define UNREACHABLE() + #endif +#endif + +// +// Signaling compilers and analyzers that a certain function cannot return may +// remove all following code and thus lead to better optimization and less +// false positives. +// +#ifndef NORETURN + #if defined (__GNUC__) || defined (__clang__) + /// + /// Signal compilers and analyzers that the function cannot return. + /// It is up to the compiler to remove any code past a call to functions + /// flagged with this attribute. + /// + #define NORETURN __attribute__((noreturn)) + #elif defined(_MSC_EXTENSIONS) && !defined(MDE_CPU_EBC) + /// + /// Signal compilers and analyzers that the function cannot return. + /// It is up to the compiler to remove any code past a call to functions + /// flagged with this attribute. + /// + #define NORETURN __declspec(noreturn) + #else + /// + /// Signal compilers and analyzers that the function cannot return. + /// It is up to the compiler to remove any code past a call to functions + /// flagged with this attribute. + /// + #define NORETURN + #endif +#endif + +// +// Should be used in combination with ANALYZER_NORETURN to avoid 'noreturn' +// returns warnings. +// +#ifndef ANALYZER_UNREACHABLE + #ifdef __clang_analyzer__ + #if __has_builtin (__builtin_unreachable) + /// + /// Signal the analyzer that this call is not reachable. + /// This excludes compilers. + /// + #define ANALYZER_UNREACHABLE() __builtin_unreachable () + #endif + #endif + + #ifndef ANALYZER_UNREACHABLE + /// + /// Signal the analyzer that this call is not reachable. + /// This excludes compilers. + /// + #define ANALYZER_UNREACHABLE() + #endif +#endif + +// +// Static Analyzers may issue errors about potential NULL-dereferences when +// dereferencing a pointer, that has been checked before, outside of a +// NULL-check. This may lead to false positives, such as when using ASSERT() +// for verification. +// +#ifndef ANALYZER_NORETURN + #ifdef __has_feature + #if __has_feature (attribute_analyzer_noreturn) + /// + /// Signal analyzers that the function cannot return. + /// This excludes compilers. + /// + #define ANALYZER_NORETURN __attribute__((analyzer_noreturn)) + #endif + #endif + + #ifndef ANALYZER_NORETURN + /// + /// Signal the analyzer that the function cannot return. + /// This excludes compilers. + /// + #define ANALYZER_NORETURN + #endif +#endif + // // For symbol name in assembly code, an extra "_" is sometimes necessary //