libbacktrace: use __has_attribute for fallthrough

Also convert some FALLTHROUGH comments to ATTRIBUTE_FALLTHROUGH. * internal.h: Use __has_attribute to check for fallthrough attribute. * elf.c (elf_zstd_decompress): Use ATTRIBUTE_FALLTHROUGH rather than a FALLTHROUGH comment.
ianlancetaylor · Jul 18, 2024 · 7e2b7da · 7e2b7da
1 parent f37b51d
commit 7e2b7da
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Showing 2 changed files with 12 additions and 7 deletions.
diff --git a/elf.c b/elf.c
@@ -4848,25 +4848,25 @@ elf_zstd_decompress (const unsigned char *pin, size_t sin,
 		  {
 		  case 8:
 		    *pout++ = *plit++;
-		    /* FALLTHROUGH */
+		    ATTRIBUTE_FALLTHROUGH;
 		  case 7:
 		    *pout++ = *plit++;
-		    /* FALLTHROUGH */
+		    ATTRIBUTE_FALLTHROUGH;
 		  case 6:
 		    *pout++ = *plit++;
-		    /* FALLTHROUGH */
+		    ATTRIBUTE_FALLTHROUGH;
 		  case 5:
 		    *pout++ = *plit++;
-		    /* FALLTHROUGH */
+		    ATTRIBUTE_FALLTHROUGH;
 		  case 4:
 		    *pout++ = *plit++;
-		    /* FALLTHROUGH */
+		    ATTRIBUTE_FALLTHROUGH;
 		  case 3:
 		    *pout++ = *plit++;
-		    /* FALLTHROUGH */
+		    ATTRIBUTE_FALLTHROUGH;
 		  case 2:
 		    *pout++ = *plit++;
-		    /* FALLTHROUGH */
+		    ATTRIBUTE_FALLTHROUGH;
 		  case 1:
 		    *pout++ = *plit++;
 		    break;

diff --git a/internal.h b/internal.h
@@ -56,6 +56,11 @@ POSSIBILITY OF SUCH DAMAGE.  */
 # endif
 #endif
 
+#ifdef __has_attribute
+# if __has_attribute(fallthrough)
+#  define ATTRIBUTE_FALLTHROUGH __attribute__ ((fallthrough))
+# endif
+#endif
 #ifndef ATTRIBUTE_FALLTHROUGH
 # if (GCC_VERSION >= 7000)
 #  define ATTRIBUTE_FALLTHROUGH __attribute__ ((__fallthrough__))