1 // This code is compiled directly on many platforms, including client 2 // platforms like Windows, Mac, and embedded systems. Before making 3 // any changes here, make sure that you're not breaking any platforms. 4 // 5 6 #ifndef DYNAMIC_DEPTH_INTERNAL_BASE_MACROS_H_ // NOLINT 7 #define DYNAMIC_DEPTH_INTERNAL_BASE_MACROS_H_ // NOLINT 8 9 #include <stddef.h> // For size_t 10 #include "base/port.h" 11 12 // The FALLTHROUGH_INTENDED macro can be used to annotate implicit fall-through 13 // between switch labels: 14 // switch (x) { 15 // case 40: 16 // case 41: 17 // if (truth_is_out_there) { 18 // ++x; 19 // FALLTHROUGH_INTENDED; // Use instead of/along with annotations in 20 // // comments. 21 // } else { 22 // return x; 23 // } 24 // case 42: 25 // ... 26 // 27 // As shown in the example above, the FALLTHROUGH_INTENDED macro should be 28 // followed by a semicolon. It is designed to mimic control-flow statements 29 // like 'break;', so it can be placed in most places where 'break;' can, but 30 // only if there are no statements on the execution path between it and the 31 // next switch label. 32 // 33 // When compiled with clang in C++11 mode, the FALLTHROUGH_INTENDED macro is 34 // expanded to [[clang::fallthrough]] attribute, which is analysed when 35 // performing switch labels fall-through diagnostic ('-Wimplicit-fallthrough'). 36 // See clang documentation on language extensions for details: 37 // http://clang.llvm.org/docs/AttributeReference.html#fallthrough-clang-fallthrough 38 // 39 // When used with unsupported compilers, the FALLTHROUGH_INTENDED macro has no 40 // effect on diagnostics. 41 // 42 // In either case this macro has no effect on runtime behavior and performance 43 // of code. 44 #if defined(__clang__) && defined(LANG_CXX11) && defined(__has_warning) 45 #if __has_feature(cxx_attributes) && __has_warning("-Wimplicit-fallthrough") 46 #define FALLTHROUGH_INTENDED [[clang::fallthrough]] // NOLINT 47 #endif 48 #endif 49 50 #ifndef FALLTHROUGH_INTENDED // NOLINT 51 #define FALLTHROUGH_INTENDED \ 52 do { \ 53 } while (0) 54 #endif 55 56 #endif // DYNAMIC_DEPTH_INTERNAL_BASE_MACROS_H_ // NOLINT 57
