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elfutils/0001-Add-GCC7-Wimplicit-fallthrough-support-fixes.patch

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From a3cc8182b2ae05290b0eafa74b70746d7befc0e4 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>
---
ChangeLog | 7 ++++++-
backends/ChangeLog | 11 +++++++++++
backends/i386_regs.c | 1 +
backends/i386_retval.c | 3 +--
backends/linux-core-note.c | 4 ++--
backends/m68k_retval.c | 4 +---
backends/ppc_regs.c | 2 +-
backends/x86_64_regs.c | 1 +
config/ChangeLog | 5 +++++
config/eu.am | 8 +++++++-
configure.ac | 10 ++++++++++
libcpu/ChangeLog | 6 +++++-
libcpu/i386_disasm.c | 2 +-
libdw/ChangeLog | 10 +++++++++-
libdw/cfi.c | 2 ++
libdw/encoded-value.h | 1 +
libdwfl/dwfl_report_elf.c | 2 +-
src/ChangeLog | 8 ++++++++
src/addr2line.c | 1 +
src/elfcompress.c | 3 ++-
src/elflint.c | 4 +++-
src/objdump.c | 4 +++-
tests/ChangeLog | 5 +++++
tests/backtrace-data.c | 1 +
tests/backtrace.c | 2 +-
25 files changed, 89 insertions(+), 18 deletions(-)
diff --git a/backends/i386_regs.c b/backends/i386_regs.c
index fb8ded3..fd963a6 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 9da797d..4aa646f 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 a4ec0be..67638d7 100644
--- a/backends/linux-core-note.c
+++ b/backends/linux-core-note.c
@@ -225,8 +225,8 @@ 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/m68k_retval.c b/backends/m68k_retval.c
index 2dd285a..c68ed02 100644
--- a/backends/m68k_retval.c
+++ b/backends/m68k_retval.c
@@ -134,10 +134,8 @@ m68k_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:
case DW_TAG_union_type:
diff --git a/backends/ppc_regs.c b/backends/ppc_regs.c
index 4b92a9a..bcf4f7a 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 2172d9f..8430440 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 4998771..8fe1e25 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),,$(STACK_USAGE_WARNING)) \
diff --git a/configure.ac b/configure.ac
index c02d4c2..c55fb9b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -311,6 +311,16 @@ CFLAGS="$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 699dd61..831afbe 100644
--- a/libcpu/i386_disasm.c
+++ b/libcpu/i386_disasm.c
@@ -819,7 +819,7 @@ i386_disasm (Ebl *ebl __attribute__((unused)),
++param_start;
break;
}
-
+ /* Fallthrough */
default:
assert (! "INVALID not handled");
}
diff --git a/libdw/cfi.c b/libdw/cfi.c
index 1fd668d..daa845f 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 48d868f..f0df4ce 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 1c6e401..73a5511 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 0ce854f..bea24ae 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 7392cb7..82ab965 100644
--- a/src/elfcompress.c
+++ b/src/elfcompress.c
@@ -155,7 +155,8 @@ 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 8b52ee2..b304a30 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 1afcd57..f84513c 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 bc5ceba..b7158da 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 2440ab3..1ff6353 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;
--
2.10.2
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