Merge pull request #7389 from shawnl/warning

tree-wide: adjust fall through comments so that gcc is happy

src/basic/MurmurHash2.c

@@ -15,6 +15,10 @@
 
 #include "MurmurHash2.h"
 
+#if __GNUC__ >= 7
+_Pragma("GCC diagnostic ignored \"-Wimplicit-fallthrough\"")
+#endif
+
 //-----------------------------------------------------------------------------
 // Platform-specific functions and macros
 

src/basic/generate-gperfs.py

@@ -7,6 +7,12 @@ import sys
 
 name, prefix, input = sys.argv[1:]
 
+print("""\
+%{
+#if __GNUC__ >= 7
+_Pragma("GCC diagnostic ignored \\"-Wimplicit-fallthrough\\"")
+#endif
+%}""")
 print("""\
 struct {}_name {{ const char* name; int id; }};
 %null-strings

src/basic/macro.h

@@ -48,6 +48,7 @@
 #define _weakref_(x) __attribute__((weakref(#x)))
 #define _alignas_(x) __attribute__((aligned(__alignof(x))))
 #define _cleanup_(x) __attribute__((cleanup(x)))
+#define _fallthrough_ __attribute__((fallthrough))
 
 /* Temporarily disable some warnings */
 #define DISABLE_WARNING_DECLARATION_AFTER_STATEMENT                     \

src/basic/siphash24.c

@@ -127,25 +127,25 @@ void siphash24_compress(const void *_in, size_t inlen, struct siphash *state) {
         switch (left) {
                 case 7:
                         state->padding |= ((uint64_t) in[6]) << 48;
-                        /* fall through */
+                        _fallthrough_;
                 case 6:
                         state->padding |= ((uint64_t) in[5]) << 40;
-                        /* fall through */
+                        _fallthrough_;
                 case 5:
                         state->padding |= ((uint64_t) in[4]) << 32;
-                        /* fall through */
+                        _fallthrough_;
                 case 4:
                         state->padding |= ((uint64_t) in[3]) << 24;
-                        /* fall through */
+                        _fallthrough_;
                 case 3:
                         state->padding |= ((uint64_t) in[2]) << 16;
-                        /* fall through */
+                        _fallthrough_;
                 case 2:
                         state->padding |= ((uint64_t) in[1]) <<  8;
-                        /* fall through */
+                        _fallthrough_;
                 case 1:
                         state->padding |= ((uint64_t) in[0]);
-                        /* fall through */
+                        _fallthrough_;
                 case 0:
                         break;
         }

src/basic/time-util.c

@@ -1382,8 +1382,7 @@ bool clock_supported(clockid_t clock) {
                 if (!clock_boottime_supported())
                         return false;
 
-                /* fall through */
-
+                _fallthrough_;
         default:
                 /* For everything else, check properly */
                 return clock_gettime(clock, &ts) >= 0;