Add -Wimplicit-fallthrough to CFLAGS and CXXFLAGS

Use it at level 4, a bit more restrictive than the default level, and
tweak our commanding comments to FALLTHROUGH.

(However, leave zic.c alone, since it's external code; to avoid the
warnings that would appear there, change CFLAGS for that file in the
Makefile.)

Author: Julien Rouhaud <rjuju123@gmail.com>
Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/20200412081825.qyo5vwwco3fv4gdo@nol
Discussion: https://postgr.es/m/flat/E1fDenm-0000C8-IJ@gemulon.postgresql.org

1 files changed, 22 insertions, 22 deletions

diff --git a/src/backend/regex/regc_pg_locale.c b/src/backend/regex/regc_pg_locale.c
index 3cc2d4d3627..d4fe01f2d1f 100644
--- a/src/backend/regex/regc_pg_locale.c
+++ b/src/backend/regex/regc_pg_locale.c
@@ -303,7 +303,7 @@ pg_wc_isdigit(pg_wchar c)
 		case PG_REGEX_LOCALE_WIDE:
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswdigit((wint_t) c);
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE:
 			return (c <= (pg_wchar) UCHAR_MAX &&
 					isdigit((unsigned char) c));
@@ -312,7 +312,7 @@ pg_wc_isdigit(pg_wchar c)
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswdigit_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE_L:
 #ifdef HAVE_LOCALE_T
 			return (c <= (pg_wchar) UCHAR_MAX &&
@@ -339,7 +339,7 @@ pg_wc_isalpha(pg_wchar c)
 		case PG_REGEX_LOCALE_WIDE:
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswalpha((wint_t) c);
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE:
 			return (c <= (pg_wchar) UCHAR_MAX &&
 					isalpha((unsigned char) c));
@@ -348,7 +348,7 @@ pg_wc_isalpha(pg_wchar c)
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswalpha_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE_L:
 #ifdef HAVE_LOCALE_T
 			return (c <= (pg_wchar) UCHAR_MAX &&
@@ -375,7 +375,7 @@ pg_wc_isalnum(pg_wchar c)
 		case PG_REGEX_LOCALE_WIDE:
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswalnum((wint_t) c);
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE:
 			return (c <= (pg_wchar) UCHAR_MAX &&
 					isalnum((unsigned char) c));
@@ -384,7 +384,7 @@ pg_wc_isalnum(pg_wchar c)
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswalnum_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE_L:
 #ifdef HAVE_LOCALE_T
 			return (c <= (pg_wchar) UCHAR_MAX &&
@@ -411,7 +411,7 @@ pg_wc_isupper(pg_wchar c)
 		case PG_REGEX_LOCALE_WIDE:
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswupper((wint_t) c);
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE:
 			return (c <= (pg_wchar) UCHAR_MAX &&
 					isupper((unsigned char) c));
@@ -420,7 +420,7 @@ pg_wc_isupper(pg_wchar c)
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswupper_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE_L:
 #ifdef HAVE_LOCALE_T
 			return (c <= (pg_wchar) UCHAR_MAX &&
@@ -447,7 +447,7 @@ pg_wc_islower(pg_wchar c)
 		case PG_REGEX_LOCALE_WIDE:
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswlower((wint_t) c);
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE:
 			return (c <= (pg_wchar) UCHAR_MAX &&
 					islower((unsigned char) c));
@@ -456,7 +456,7 @@ pg_wc_islower(pg_wchar c)
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswlower_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE_L:
 #ifdef HAVE_LOCALE_T
 			return (c <= (pg_wchar) UCHAR_MAX &&
@@ -483,7 +483,7 @@ pg_wc_isgraph(pg_wchar c)
 		case PG_REGEX_LOCALE_WIDE:
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswgraph((wint_t) c);
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE:
 			return (c <= (pg_wchar) UCHAR_MAX &&
 					isgraph((unsigned char) c));
@@ -492,7 +492,7 @@ pg_wc_isgraph(pg_wchar c)
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswgraph_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE_L:
 #ifdef HAVE_LOCALE_T
 			return (c <= (pg_wchar) UCHAR_MAX &&
@@ -519,7 +519,7 @@ pg_wc_isprint(pg_wchar c)
 		case PG_REGEX_LOCALE_WIDE:
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswprint((wint_t) c);
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE:
 			return (c <= (pg_wchar) UCHAR_MAX &&
 					isprint((unsigned char) c));
@@ -528,7 +528,7 @@ pg_wc_isprint(pg_wchar c)
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswprint_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE_L:
 #ifdef HAVE_LOCALE_T
 			return (c <= (pg_wchar) UCHAR_MAX &&
@@ -555,7 +555,7 @@ pg_wc_ispunct(pg_wchar c)
 		case PG_REGEX_LOCALE_WIDE:
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswpunct((wint_t) c);
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE:
 			return (c <= (pg_wchar) UCHAR_MAX &&
 					ispunct((unsigned char) c));
@@ -564,7 +564,7 @@ pg_wc_ispunct(pg_wchar c)
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswpunct_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE_L:
 #ifdef HAVE_LOCALE_T
 			return (c <= (pg_wchar) UCHAR_MAX &&
@@ -591,7 +591,7 @@ pg_wc_isspace(pg_wchar c)
 		case PG_REGEX_LOCALE_WIDE:
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswspace((wint_t) c);
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE:
 			return (c <= (pg_wchar) UCHAR_MAX &&
 					isspace((unsigned char) c));
@@ -600,7 +600,7 @@ pg_wc_isspace(pg_wchar c)
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return iswspace_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE_L:
 #ifdef HAVE_LOCALE_T
 			return (c <= (pg_wchar) UCHAR_MAX &&
@@ -631,7 +631,7 @@ pg_wc_toupper(pg_wchar c)
 				return pg_ascii_toupper((unsigned char) c);
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return towupper((wint_t) c);
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE:
 			/* force C behavior for ASCII characters, per comments above */
 			if (c <= (pg_wchar) 127)
@@ -644,7 +644,7 @@ pg_wc_toupper(pg_wchar c)
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return towupper_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE_L:
 #ifdef HAVE_LOCALE_T
 			if (c <= (pg_wchar) UCHAR_MAX)
@@ -675,7 +675,7 @@ pg_wc_tolower(pg_wchar c)
 				return pg_ascii_tolower((unsigned char) c);
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return towlower((wint_t) c);
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE:
 			/* force C behavior for ASCII characters, per comments above */
 			if (c <= (pg_wchar) 127)
@@ -688,7 +688,7 @@ pg_wc_tolower(pg_wchar c)
 			if (sizeof(wchar_t) >= 4 || c <= (pg_wchar) 0xFFFF)
 				return towlower_l((wint_t) c, pg_regex_locale->info.lt);
 #endif
-			/* FALL THRU */
+			/* FALLTHROUGH */
 		case PG_REGEX_LOCALE_1BYTE_L:
 #ifdef HAVE_LOCALE_T
 			if (c <= (pg_wchar) UCHAR_MAX)