| From 09949994e76eea3c1230a5c88ffa8fdf588b120f Mon Sep 17 00:00:00 2001 |
| From: Mark Wielaard <mjw@redhat.com> |
| Date: Wed, 2 Nov 2016 13:29:26 +0100 |
| Subject: [PATCH] Add GCC7 -Wimplicit-fallthrough support/fixes. |
| |
| GCC7 will have a new -Wimplicit-fallthrough warning. It did catch one |
| small buglet in elflint option procession. So it seems useful to enable |
| to make sure all swatch case fallthroughs are deliberate. |
| |
| Add configure check to detect whether gcc support -Wimplicit-fallthrough |
| and enable it. Add fixes and explicit fallthrough comments where necessary. |
| |
| Signed-off-by: Mark Wielaard <mjw@redhat.com> |
| |
| Upstream-Status: Backport |
| Upstream-Commit: a3cc8182b2ae05290b0eafa74b70746d7befc0e4 |
| --- |
| backends/alpha_retval.c | 4 +--- |
| backends/i386_regs.c | 1 + |
| backends/i386_retval.c | 3 +-- |
| backends/linux-core-note.c | 4 ++-- |
| backends/ppc_regs.c | 2 +- |
| backends/x86_64_regs.c | 1 + |
| config/eu.am | 8 +++++++- |
| configure.ac | 10 ++++++++++ |
| libcpu/i386_disasm.c | 2 +- |
| libdw/cfi.c | 2 ++ |
| libdw/encoded-value.h | 1 + |
| libdwfl/dwfl_report_elf.c | 2 +- |
| src/addr2line.c | 1 + |
| src/elfcompress.c | 3 ++- |
| src/elflint.c | 4 +++- |
| src/objdump.c | 4 +++- |
| tests/backtrace-data.c | 1 + |
| tests/backtrace.c | 2 +- |
| 18 files changed, 40 insertions(+), 15 deletions(-) |
| |
| diff --git a/backends/alpha_retval.c b/backends/alpha_retval.c |
| index 53dbfa45..7232b462 100644 |
| --- a/backends/alpha_retval.c |
| +++ b/backends/alpha_retval.c |
| @@ -130,9 +130,7 @@ alpha_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) |
| return nloc_intreg; |
| } |
| } |
| - |
| - /* Else fall through. */ |
| - |
| + /* Fallthrough */ |
| case DW_TAG_structure_type: |
| case DW_TAG_class_type: |
| case DW_TAG_union_type: |
| diff --git a/backends/i386_regs.c b/backends/i386_regs.c |
| index fb8ded33..fd963a62 100644 |
| --- a/backends/i386_regs.c |
| +++ b/backends/i386_regs.c |
| @@ -92,6 +92,7 @@ i386_register_info (Ebl *ebl __attribute__ ((unused)), |
| case 5: |
| case 8: |
| *type = DW_ATE_address; |
| + /* Fallthrough */ |
| case 0 ... 3: |
| case 6 ... 7: |
| name[0] = 'e'; |
| diff --git a/backends/i386_retval.c b/backends/i386_retval.c |
| index 9da797d5..4aa646fe 100644 |
| --- a/backends/i386_retval.c |
| +++ b/backends/i386_retval.c |
| @@ -122,9 +122,8 @@ i386_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) |
| return nloc_intreg; |
| if (size <= 8) |
| return nloc_intregpair; |
| - |
| - /* Else fall through. */ |
| } |
| + /* Fallthrough */ |
| |
| case DW_TAG_structure_type: |
| case DW_TAG_class_type: |
| diff --git a/backends/linux-core-note.c b/backends/linux-core-note.c |
| index ff2b226f..321721f3 100644 |
| --- a/backends/linux-core-note.c |
| +++ b/backends/linux-core-note.c |
| @@ -219,8 +219,8 @@ EBLHOOK(core_note) (const GElf_Nhdr *nhdr, const char *name, |
| case sizeof "CORE": |
| if (memcmp (name, "CORE", nhdr->n_namesz) == 0) |
| break; |
| - /* Buggy old Linux kernels didn't terminate "LINUX". |
| - Fall through. */ |
| + /* Buggy old Linux kernels didn't terminate "LINUX". */ |
| + /* Fall through. */ |
| |
| case sizeof "LINUX": |
| if (memcmp (name, "LINUX", nhdr->n_namesz) == 0) |
| diff --git a/backends/ppc_regs.c b/backends/ppc_regs.c |
| index 4b92a9aa..bcf4f7a3 100644 |
| --- a/backends/ppc_regs.c |
| +++ b/backends/ppc_regs.c |
| @@ -140,7 +140,7 @@ ppc_register_info (Ebl *ebl __attribute__ ((unused)), |
| case 100: |
| if (*bits == 32) |
| return stpcpy (name, "mq") + 1 - name; |
| - |
| + /* Fallthrough */ |
| case 102 ... 107: |
| name[0] = 's'; |
| name[1] = 'p'; |
| diff --git a/backends/x86_64_regs.c b/backends/x86_64_regs.c |
| index 2172d9f1..84304407 100644 |
| --- a/backends/x86_64_regs.c |
| +++ b/backends/x86_64_regs.c |
| @@ -87,6 +87,7 @@ x86_64_register_info (Ebl *ebl __attribute__ ((unused)), |
| |
| case 6 ... 7: |
| *type = DW_ATE_address; |
| + /* Fallthrough */ |
| case 0 ... 5: |
| name[0] = 'r'; |
| name[1] = baseregs[regno][0]; |
| diff --git a/config/eu.am b/config/eu.am |
| index 4998771d..8fe1e259 100644 |
| --- a/config/eu.am |
| +++ b/config/eu.am |
| @@ -61,10 +61,16 @@ else |
| NULL_DEREFERENCE_WARNING= |
| endif |
| |
| +if HAVE_IMPLICIT_FALLTHROUGH_WARNING |
| +IMPLICIT_FALLTHROUGH_WARNING=-Wimplicit-fallthrough |
| +else |
| +IMPLICIT_FALLTHROUGH_WARNING= |
| +endif |
| + |
| AM_CFLAGS = -std=gnu99 -Wall -Wshadow -Wformat=2 \ |
| -Wold-style-definition -Wstrict-prototypes \ |
| $(LOGICAL_OP_WARNING) $(DUPLICATED_COND_WARNING) \ |
| - $(NULL_DEREFERENCE_WARNING) \ |
| + $(NULL_DEREFERENCE_WARNING) $(IMPLICIT_FALLTHROUGH_WARNING) \ |
| $(if $($(*F)_no_Werror),,-Werror) \ |
| $(if $($(*F)_no_Wunused),,-Wunused -Wextra) \ |
| $(if $($(*F)_no_Wstack_usage),,$(STACK_USAGE_WARNING)) \ |
| diff --git a/configure.ac b/configure.ac |
| index 86a69c66..35850c64 100644 |
| --- a/configure.ac |
| +++ b/configure.ac |
| @@ -336,6 +336,16 @@ CFLAGS="$old_CFLAGS"]) |
| AM_CONDITIONAL(HAVE_NULL_DEREFERENCE_WARNING, |
| [test "x$ac_cv_null_dereference" != "xno"]) |
| |
| +# -Wimplicit-fallthrough was added by GCC7 |
| +AC_CACHE_CHECK([whether gcc accepts -Wimplicit-fallthrough], ac_cv_implicit_fallthrough, [dnl |
| +old_CFLAGS="$CFLAGS" |
| +CFLAGS="$CFLAGS -Wimplicit-fallthrough -Werror" |
| +AC_COMPILE_IFELSE([AC_LANG_SOURCE([])], |
| + ac_cv_implicit_fallthrough=yes, ac_cv_implicit_fallthrough=no) |
| +CFLAGS="$old_CFLAGS"]) |
| +AM_CONDITIONAL(HAVE_IMPLICIT_FALLTHROUGH_WARNING, |
| + [test "x$ac_cv_implicit_fallthrough" != "xno"]) |
| + |
| dnl Check if we have argp available from our libc |
| AC_LINK_IFELSE( |
| [AC_LANG_PROGRAM( |
| diff --git a/libcpu/i386_disasm.c b/libcpu/i386_disasm.c |
| index 832241f2..1a584635 100644 |
| --- a/libcpu/i386_disasm.c |
| +++ b/libcpu/i386_disasm.c |
| @@ -819,7 +819,7 @@ i386_disasm (const uint8_t **startp, const uint8_t *end, GElf_Addr addr, |
| ++param_start; |
| break; |
| } |
| - |
| + /* Fallthrough */ |
| default: |
| assert (! "INVALID not handled"); |
| } |
| diff --git a/libdw/cfi.c b/libdw/cfi.c |
| index 1fd668d7..daa845f3 100644 |
| --- a/libdw/cfi.c |
| +++ b/libdw/cfi.c |
| @@ -138,6 +138,7 @@ execute_cfi (Dwarf_CFI *cache, |
| |
| case DW_CFA_advance_loc1: |
| operand = *program++; |
| + /* Fallthrough */ |
| case DW_CFA_advance_loc + 0 ... DW_CFA_advance_loc + CFI_PRIMARY_MAX: |
| advance_loc: |
| loc += operand * cie->code_alignment_factor; |
| @@ -300,6 +301,7 @@ execute_cfi (Dwarf_CFI *cache, |
| |
| case DW_CFA_restore_extended: |
| get_uleb128 (operand, program, end); |
| + /* Fallthrough */ |
| case DW_CFA_restore + 0 ... DW_CFA_restore + CFI_PRIMARY_MAX: |
| |
| if (unlikely (abi_cfi) && likely (opcode == DW_CFA_restore)) |
| diff --git a/libdw/encoded-value.h b/libdw/encoded-value.h |
| index 48d868fb..f0df4cec 100644 |
| --- a/libdw/encoded-value.h |
| +++ b/libdw/encoded-value.h |
| @@ -64,6 +64,7 @@ encoded_value_size (const Elf_Data *data, const unsigned char e_ident[], |
| if (*end++ & 0x80u) |
| return end - p; |
| } |
| + return 0; |
| |
| default: |
| return 0; |
| diff --git a/libdwfl/dwfl_report_elf.c b/libdwfl/dwfl_report_elf.c |
| index 1c6e401d..73a5511a 100644 |
| --- a/libdwfl/dwfl_report_elf.c |
| +++ b/libdwfl/dwfl_report_elf.c |
| @@ -170,7 +170,7 @@ __libdwfl_elf_address_range (Elf *elf, GElf_Addr base, bool add_p_vaddr, |
| /* An assigned base address is meaningless for these. */ |
| base = 0; |
| add_p_vaddr = true; |
| - |
| + /* Fallthrough. */ |
| case ET_DYN: |
| default:; |
| size_t phnum; |
| diff --git a/src/addr2line.c b/src/addr2line.c |
| index 0ce854f6..bea24aea 100644 |
| --- a/src/addr2line.c |
| +++ b/src/addr2line.c |
| @@ -632,6 +632,7 @@ handle_address (const char *string, Dwfl *dwfl) |
| case 1: |
| addr = 0; |
| j = i; |
| + /* Fallthrough */ |
| case 2: |
| if (string[j] != '\0') |
| break; |
| diff --git a/src/elfcompress.c b/src/elfcompress.c |
| index d0ca469c..57afa116 100644 |
| --- a/src/elfcompress.c |
| +++ b/src/elfcompress.c |
| @@ -153,7 +153,8 @@ parse_opt (int key, char *arg __attribute__ ((unused)), |
| argp_error (state, |
| N_("Only one input file allowed together with '-o'")); |
| /* We only use this for checking the number of arguments, we don't |
| - actually want to consume them, so fallthrough. */ |
| + actually want to consume them. */ |
| + /* Fallthrough */ |
| default: |
| return ARGP_ERR_UNKNOWN; |
| } |
| diff --git a/src/elflint.c b/src/elflint.c |
| index 15b12f6f..2c45fcb8 100644 |
| --- a/src/elflint.c |
| +++ b/src/elflint.c |
| @@ -210,6 +210,7 @@ parse_opt (int key, char *arg __attribute__ ((unused)), |
| |
| case 'd': |
| is_debuginfo = true; |
| + break; |
| |
| case ARGP_gnuld: |
| gnuld = true; |
| @@ -3963,6 +3964,7 @@ section [%2zu] '%s': merge flag set but entry size is zero\n"), |
| case SHT_NOBITS: |
| if (is_debuginfo) |
| break; |
| + /* Fallthrough */ |
| default: |
| ERROR (gettext ("\ |
| section [%2zu] '%s' has unexpected type %d for an executable section\n"), |
| @@ -4305,7 +4307,7 @@ section [%2d] '%s': unknown core file note type %" PRIu32 |
| if (nhdr.n_namesz == sizeof "Linux" |
| && !memcmp (data->d_buf + name_offset, "Linux", sizeof "Linux")) |
| break; |
| - |
| + /* Fallthrough */ |
| default: |
| if (shndx == 0) |
| ERROR (gettext ("\ |
| diff --git a/src/objdump.c b/src/objdump.c |
| index 0aa41e89..94e9e021 100644 |
| --- a/src/objdump.c |
| +++ b/src/objdump.c |
| @@ -234,7 +234,9 @@ parse_opt (int key, char *arg, |
| program_invocation_short_name); |
| exit (EXIT_FAILURE); |
| } |
| - |
| + /* We only use this for checking the number of arguments, we don't |
| + actually want to consume them. */ |
| + /* Fallthrough */ |
| default: |
| return ARGP_ERR_UNKNOWN; |
| } |
| diff --git a/tests/backtrace-data.c b/tests/backtrace-data.c |
| index bc5ceba0..b7158dae 100644 |
| --- a/tests/backtrace-data.c |
| +++ b/tests/backtrace-data.c |
| @@ -250,6 +250,7 @@ thread_callback (Dwfl_Thread *thread, void *thread_arg __attribute__ ((unused))) |
| break; |
| case -1: |
| error (1, 0, "dwfl_thread_getframes: %s", dwfl_errmsg (-1)); |
| + break; |
| default: |
| abort (); |
| } |
| diff --git a/tests/backtrace.c b/tests/backtrace.c |
| index 12476430..bf5995b4 100644 |
| --- a/tests/backtrace.c |
| +++ b/tests/backtrace.c |
| @@ -123,7 +123,7 @@ callback_verify (pid_t tid, unsigned frameno, Dwarf_Addr pc, |
| assert (symname2 == NULL || strcmp (symname2, "jmp") != 0); |
| break; |
| } |
| - /* PASSTHRU */ |
| + /* FALLTHRU */ |
| case 4: |
| assert (symname != NULL && strcmp (symname, "stdarg") == 0); |
| break; |
| -- |
| 2.13.0 |
| |