commit 32db86d558193ad4ad5a00926ce3c350c89eb8df Author: Joseph Myers Date: Tue Feb 12 10:30:34 2019 +0000 Add fall-through comments. This patch adds fall-through comments in some cases where -Wextra produces implicit-fallthrough warnings. The patch is non-exhaustive. Apart from architecture-specific code for non-x86_64 architectures, it does not change sunrpc/xdr.c (legacy code, probably should have such changes, but left to be dealt with separately), or places that already had comments about the fall-through but not matching the form expected by -Wimplicit-fallthrough=3 (the default level with -Wextra; my inclination is to adjust those comments to match rather than downgrading to -Wimplicit-fallthrough=1 to allow any comment), or one place where I thought the implicit fallthrough was not correct and so should be handled separately as a bug fix. I think the key thing to consider in review of this patch is whether the fall-through is indeed intended and correct in each place where such a comment is added. Tested for x86_64. * elf/dl-exception.c (_dl_exception_create_format): Add fall-through comments. * elf/ldconfig.c (parse_conf_include): Likewise. * elf/rtld.c (print_statistics): Likewise. * locale/programs/charmap.c (parse_charmap): Likewise. * misc/mntent_r.c (__getmntent_r): Likewise. * posix/wordexp.c (parse_arith): Likewise. (parse_backtick): Likewise. * resolv/ns_ttl.c (ns_parse_ttl): Likewise. * sysdeps/x86/cpu-features.c (init_cpu_features): Likewise. * sysdeps/x86_64/dl-machine.h (elf_machine_rela): Likewise. diff --git a/elf/dl-exception.c b/elf/dl-exception.c index 3e8e0ba3f1442005..d24bf30a5cf39bc2 100644 --- a/elf/dl-exception.c +++ b/elf/dl-exception.c @@ -123,6 +123,7 @@ _dl_exception_create_format (struct dl_exception *exception, const char *objname ++p; break; } + /* Fall through. */ case 'x': length += INT_WIDTH / 4; break; diff --git a/elf/ldconfig.c b/elf/ldconfig.c index fbdd814edf59bc77..ed7d9ab0412d93fd 100644 --- a/elf/ldconfig.c +++ b/elf/ldconfig.c @@ -1228,6 +1228,7 @@ parse_conf_include (const char *config_file, unsigned int lineno, case GLOB_NOSPACE: errno = ENOMEM; + /* Fall through. */ case GLOB_ABORTED: if (opt_verbose) error (0, errno, _("%s:%u: cannot read directory %s"), diff --git a/elf/rtld.c b/elf/rtld.c index 7f030f75a22c532e..8bb5f548a0ff8eb4 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -2734,8 +2734,10 @@ print_statistics (hp_timing_t *rtld_total_timep) { case 3: *wp++ = *cp++; + /* Fall through. */ case 2: *wp++ = *cp++; + /* Fall through. */ case 1: *wp++ = '.'; *wp++ = *cp++; @@ -2797,8 +2799,10 @@ print_statistics (hp_timing_t *rtld_total_timep) { case 3: *wp++ = *cp++; + /* Fall through. */ case 2: *wp++ = *cp++; + /* Fall through. */ case 1: *wp++ = '.'; *wp++ = *cp++; diff --git a/locale/programs/charmap.c b/locale/programs/charmap.c index 2d54dd3c027d11d2..8041a0e5d292f3f5 100644 --- a/locale/programs/charmap.c +++ b/locale/programs/charmap.c @@ -713,6 +713,7 @@ only WIDTH definitions are allowed to follow the CHARMAP definition")); state = 95; continue; } + /* Fall through. */ case 96: if (nowtok != tok_number) diff --git a/misc/mntent_r.c b/misc/mntent_r.c index 7bb224f044150ab4..add39d4537eaccb5 100644 --- a/misc/mntent_r.c +++ b/misc/mntent_r.c @@ -167,8 +167,10 @@ get_mnt_entry (FILE *stream, struct mntent *mp, char *buffer, int bufsiz) { case 0: mp->mnt_freq = 0; + /* Fall through. */ case 1: mp->mnt_passno = 0; + /* Fall through. */ case 2: break; } diff --git a/posix/wordexp.c b/posix/wordexp.c index 7548e0329fdeafaa..048a8068544c81fa 100644 --- a/posix/wordexp.c +++ b/posix/wordexp.c @@ -799,6 +799,7 @@ parse_arith (char **word, size_t *word_length, size_t *max_length, case '(': ++paren_depth; + /* Fall through. */ default: expr = w_addchar (expr, &expr_length, &expr_maxlen, words[*offset]); if (expr == NULL) @@ -2127,6 +2128,7 @@ parse_backtick (char **word, size_t *word_length, size_t *max_length, case '\'': squoting = 1 - squoting; + /* Fall through. */ default: comm = w_addchar (comm, &comm_length, &comm_maxlen, words[*offset]); if (comm == NULL) diff --git a/resolv/ns_ttl.c b/resolv/ns_ttl.c index 079948790b94b05e..d29d9dc00cfcab2c 100644 --- a/resolv/ns_ttl.c +++ b/resolv/ns_ttl.c @@ -113,9 +113,13 @@ ns_parse_ttl(const char *src, u_long *dst) { ch = toupper(ch); switch (ch) { case 'W': tmp *= 7; + /* Fall through. */ case 'D': tmp *= 24; + /* Fall through. */ case 'H': tmp *= 60; + /* Fall through. */ case 'M': tmp *= 60; + /* Fall through. */ case 'S': break; default: goto einval; } diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c index 3a02a9c7d08f9603..ade37a9bb3de86cc 100644 --- a/sysdeps/x86/cpu-features.c +++ b/sysdeps/x86/cpu-features.c @@ -374,6 +374,7 @@ init_cpu_features (struct cpu_features *cpu_features) of Core i3/i5/i7 processors if AVX is available. */ if (!CPU_FEATURES_CPU_P (cpu_features, AVX)) break; + /* Fall through. */ case 0x1a: case 0x1e: @@ -401,6 +402,7 @@ init_cpu_features (struct cpu_features *cpu_features) /* Xeon E7 v3 with stepping >= 4 has working TSX. */ if (stepping >= 4) break; + /* Fall through. */ case 0x3c: case 0x45: case 0x46: diff --git a/sysdeps/x86_64/dl-machine.h b/sysdeps/x86_64/dl-machine.h index 1942ed5061d18c68..23afb3c05dbe17d6 100644 --- a/sysdeps/x86_64/dl-machine.h +++ b/sysdeps/x86_64/dl-machine.h @@ -347,6 +347,7 @@ elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc, /* Set to symbol size plus addend. */ value = sym->st_size; # endif + /* Fall through. */ case R_X86_64_GLOB_DAT: case R_X86_64_JUMP_SLOT: *reloc_addr = value + reloc->r_addend; @@ -460,6 +461,7 @@ elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc, /* Set to symbol size plus addend. */ value = sym->st_size; # endif + /* Fall through. */ case R_X86_64_32: value += reloc->r_addend; *(unsigned int *) reloc_addr = value;