commit b4ee740ab8096dda0c2b4dd1d1782a3f5efc55c2
Author: Jason Merrill <jason@redhat.com>
Date: Wed Sep 2 16:43:48 2015 -0400
Disconnect -Wabi=<n> from -fabi-compat-version=<n>.
gcc/c-family/
* c-common.h (abi_compat_version_crosses): New.
(warn_abi_version): Declare.
* c-common.c: Define it.
* c-opts.c (c_common_post_options): Handle it.
flag_abi_compat_version defaults to 8.
gcc/cp/
* mangle.c (abi_warn_or_compat_version_crosses): New.
Use it instead of abi_version_crosses.
(mangle_decl): Deal with -fabi-compat-version and -Wabi separately.
@@ -239,6 +239,9 @@ const char *constant_string_class_name;
/* C++ language option variables. */
+/* The reference version of the ABI for -Wabi. */
+
+int warn_abi_version = -1;
/* Nonzero means generate separate instantiation control files and
juggle them at link time. */
@@ -648,14 +648,24 @@ extern const char *constant_string_class_name;
/* C++ language option variables. */
+/* The reference version of the ABI for -Wabi. */
+
+extern int warn_abi_version;
/* Return TRUE if one of {flag_abi_version,flag_abi_compat_version} is
- less than N and the other is at least N, for use by -Wabi. */
-#define abi_version_crosses(N) \
+ less than N and the other is at least N. */
+#define abi_compat_version_crosses(N) \
(abi_version_at_least(N) \
!= (flag_abi_compat_version == 0 \
|| flag_abi_compat_version >= (N)))
+/* Return TRUE if one of {flag_abi_version,warn_abi_version} is
+ less than N and the other is at least N, for use by -Wabi. */
+#define abi_version_crosses(N) \
+ (abi_version_at_least(N) \
+ != (warn_abi_version == 0 \
+ || warn_abi_version >= (N)))
+
/* Nonzero means generate separate instantiation control files and
juggle them at link time. */
@@ -397,7 +397,9 @@ c_common_handle_option (size_t scode, const char *arg, int value,
warning (0, "%<-Wabi=1%> is not supported, using =2");
value = 2;
}
- flag_abi_compat_version = value;
+ warn_abi_version = value;
+ if (flag_abi_compat_version == -1)
+ flag_abi_compat_version = value;
break;
case OPT_fcanonical_system_headers:
@@ -870,6 +872,14 @@ c_common_post_options (const char **pfilename)
if (flag_declone_ctor_dtor == -1)
flag_declone_ctor_dtor = optimize_size;
+ if (warn_abi_version == -1)
+ {
+ if (flag_abi_compat_version != -1)
+ warn_abi_version = flag_abi_compat_version;
+ else
+ warn_abi_version = 0;
+ }
+
if (flag_abi_compat_version == 1)
{
warning (0, "%<-fabi-compat-version=1%> is not supported, using =2");
@@ -877,13 +887,9 @@ c_common_post_options (const char **pfilename)
}
else if (flag_abi_compat_version == -1)
{
- /* Generate compatibility aliases for ABI v2 (3.4-4.9) by default. */
- flag_abi_compat_version = (flag_abi_version == 0 ? 2 : 0);
-
- /* But don't warn about backward compatibility unless explicitly
- requested with -Wabi=n. */
- if (flag_abi_version == 0)
- warn_abi = false;
+ /* Generate compatibility aliases for ABI v8 (5.1) by default. */
+ flag_abi_compat_version
+ = (flag_abi_version == 0 ? 8 : 0);
}
/* Change flag_abi_version to be the actual current ABI level for the
@@ -94,6 +94,11 @@ along with GCC; see the file COPYING3. If not see
|| (CLASSTYPE_TEMPLATE_INFO (NODE) != NULL \
&& (PRIMARY_TEMPLATE_P (CLASSTYPE_TI_TEMPLATE (NODE))))))
+/* For deciding whether to set G.need_abi_warning, we need to consider both
+ warn_abi_version and flag_abi_compat_version. */
+#define abi_warn_or_compat_version_crosses(N) \
+ (abi_version_crosses (N) || abi_compat_version_crosses (N))
+
/* Things we only need one of. This module is not reentrant. */
struct GTY(()) globals {
/* An array of the current substitution candidates, in the order
@@ -829,7 +834,7 @@ write_name (tree decl, const int ignore_local_scope)
gcc_assert (context != NULL_TREE);
- if (abi_version_crosses (7)
+ if (abi_warn_or_compat_version_crosses (7)
&& ignore_local_scope
&& TREE_CODE (context) == PARM_DECL)
G.need_abi_warning = 1;
@@ -1918,7 +1923,7 @@ write_type (tree type)
write_function_type (t);
else
write_type (t);
- if (abi_version_crosses (8))
+ if (abi_warn_or_compat_version_crosses (8))
G.need_abi_warning = 1;
}
else
@@ -2027,7 +2032,7 @@ write_type (tree type)
but you can't have a pointer/reference to such a type. */
if (TREE_CODE (target) == FUNCTION_TYPE)
{
- if (abi_version_crosses (5)
+ if (abi_warn_or_compat_version_crosses (5)
&& TYPE_QUALS (target) != TYPE_UNQUALIFIED)
G.need_abi_warning = 1;
if (abi_version_at_least (5))
@@ -2073,7 +2078,7 @@ write_type (tree type)
}
else
write_string ("U8__vector");
- if (abi_version_crosses (4))
+ if (abi_warn_or_compat_version_crosses (4))
G.need_abi_warning = 1;
write_type (TREE_TYPE (type));
break;
@@ -2110,7 +2115,7 @@ write_type (tree type)
if (etype && !type_uses_auto (etype))
{
- if (abi_version_crosses (5))
+ if (abi_warn_or_compat_version_crosses (5))
G.need_abi_warning = 1;
if (!abi_version_at_least (5))
{
@@ -2135,7 +2140,7 @@ write_type (tree type)
write_string ("Dn");
if (abi_version_at_least (7))
++is_builtin_type;
- if (abi_version_crosses (7))
+ if (abi_warn_or_compat_version_crosses (7))
G.need_abi_warning = 1;
break;
@@ -2207,7 +2212,7 @@ write_CV_qualifiers_for_type (const tree type)
&& !is_attribute_p ("abi_tag", name))
vec.safe_push (a);
}
- if (abi_version_crosses (10) && !vec.is_empty ())
+ if (abi_warn_or_compat_version_crosses (10) && !vec.is_empty ())
G.need_abi_warning = true;
if (abi_version_at_least (10))
{
@@ -2747,7 +2752,7 @@ write_expression (tree expr)
write_char ('L');
write_unsigned_number (delta - 1);
}
- if (abi_version_crosses (5))
+ if (abi_warn_or_compat_version_crosses (5))
G.need_abi_warning = true;
}
write_char ('p');
@@ -2989,7 +2994,7 @@ write_expression (tree expr)
if (code == CONST_CAST_EXPR
|| code == STATIC_CAST_EXPR)
{
- if (abi_version_crosses (6))
+ if (abi_warn_or_compat_version_crosses (6))
G.need_abi_warning = 1;
if (!abi_version_at_least (6))
name = operator_name_info[CAST_EXPR].mangled_name;
@@ -3063,7 +3068,7 @@ write_expression (tree expr)
case PREDECREMENT_EXPR:
if (abi_version_at_least (6))
write_char ('_');
- if (abi_version_crosses (6))
+ if (abi_warn_or_compat_version_crosses (6))
G.need_abi_warning = 1;
/* Fall through. */
@@ -3200,7 +3205,7 @@ write_template_arg (tree node)
{
if (abi_version_at_least (6))
node = BASELINK_FUNCTIONS (node);
- if (abi_version_crosses (6))
+ if (abi_warn_or_compat_version_crosses (6))
/* We wrongly wrapped a class-scope function in X/E. */
G.need_abi_warning = 1;
}
@@ -3214,7 +3219,7 @@ write_template_arg (tree node)
write_char ('J');
else
write_char ('I');
- if (abi_version_crosses (6))
+ if (abi_warn_or_compat_version_crosses (6))
G.need_abi_warning = 1;
for (i = 0; i < length; ++i)
write_template_arg (TREE_VEC_ELT (args, i));
@@ -3238,7 +3243,7 @@ write_template_arg (tree node)
write_char ('Z');
else
write_string ("_Z");
- if (abi_version_crosses (3))
+ if (abi_warn_or_compat_version_crosses (3))
G.need_abi_warning = 1;
write_encoding (node);
write_char ('E');
@@ -3627,32 +3632,41 @@ mangle_decl (const tree decl)
}
save_ver = flag_abi_version;
+
flag_abi_version = flag_abi_compat_version;
id2 = mangle_decl_string (decl);
id2 = targetm.mangle_decl_assembler_name (decl, id2);
- flag_abi_version = save_ver;
- if (id2 == id)
- return;
+ if (id2 != id)
+ note_mangling_alias (decl, id2);
if (warn_abi)
{
- if (flag_abi_compat_version != 0
- && abi_version_at_least (flag_abi_compat_version))
+ if (flag_abi_compat_version != warn_abi_version)
+ {
+ flag_abi_version = warn_abi_version;
+ id2 = mangle_decl_string (decl);
+ id2 = targetm.mangle_decl_assembler_name (decl, id2);
+ }
+
+ if (id2 == id)
+ /* OK. */;
+ else if (warn_abi_version != 0
+ && abi_version_at_least (warn_abi_version))
warning_at (DECL_SOURCE_LOCATION (G.entity), OPT_Wabi,
"the mangled name of %qD changed between "
"-fabi-version=%d (%D) and -fabi-version=%d (%D)",
- G.entity, flag_abi_compat_version, id2,
+ G.entity, warn_abi_version, id2,
flag_abi_version, id);
else
warning_at (DECL_SOURCE_LOCATION (G.entity), OPT_Wabi,
"the mangled name of %qD changes between "
"-fabi-version=%d (%D) and -fabi-version=%d (%D)",
G.entity, flag_abi_version, id,
- flag_abi_compat_version, id2);
+ warn_abi_version, id2);
}
- note_mangling_alias (decl, id2);
+ flag_abi_version = save_ver;
}
}
@@ -2134,6 +2134,13 @@ scope.
Version 8, which first appeared in G++ 4.9, corrects the substitution
behavior of function types with function-cv-qualifiers.
+Version 9, which first appeared in G++ 5.2, corrects the alignment of
+@code{nullptr_t}.
+
+Version 10, which first appeared in G++ 6.1, adds mangling of
+attributes that affect type identity, such as ia32 calling convention
+attributes (e.g. @samp{stdcall}).
+
See also @option{-Wabi}.
@item -fabi-compat-version=@var{n}
@@ -2143,10 +2150,15 @@ works around mangling changes by creating an alias with the correct
mangled name when defining a symbol with an incorrect mangled name.
This switch specifies which ABI version to use for the alias.
-With @option{-fabi-version=0} (the default), this defaults to 2. If
-another ABI version is explicitly selected, this defaults to 0.
+With @option{-fabi-version=0} (the default), this defaults to 8 (GCC 5
+compatibility). If another ABI version is explicitly selected, this
+defaults to 0. For compatibility with GCC versions 3.2 through 4.9,
+use @option{-fabi-compat-version=2}.
-The compatibility version is also set by @option{-Wabi=@var{n}}.
+If this option is not provided but @option{-Wabi=@var{n}} is, that
+version is used for compatibility aliases. If this option is provided
+along with @option{-Wabi} (without the version), the version from this
+option is used for the warning.
@item -fno-access-control
@opindex fno-access-control
@@ -2559,13 +2571,25 @@ have meanings only for C++ programs:
@item -Wabi @r{(C, Objective-C, C++ and Objective-C++ only)}
@opindex Wabi
@opindex Wno-abi
-When an explicit @option{-fabi-version=@var{n}} option is used, causes
-G++ to warn when it generates code that is probably not compatible with the
-vendor-neutral C++ ABI@. Since G++ now defaults to
-@option{-fabi-version=0}, @option{-Wabi} has no effect unless either
-an older ABI version is selected (with @option{-fabi-version=@var{n}})
-or an older compatibility version is selected (with
-@option{-Wabi=@var{n}} or @option{-fabi-compat-version=@var{n}}).
+Warn when G++ it generates code that is probably not compatible with
+the vendor-neutral C++ ABI@. Since G++ now defaults to updating the
+ABI with each major release, normally @option{-Wabi} will warn only if
+there is a check added later in a release series for an ABI issue
+discovered since the initial release. @option{-Wabi} will warn about
+more things if an older ABI version is selected (with
+@option{-fabi-version=@var{n}}).
+
+@option{-Wabi} can also be used with an explicit version number to
+warn about compatibility with a particular @option{-fabi-version}
+level, e.g. @option{-Wabi=2} to warn about changes relative to
+@option{-fabi-version=2}.
+
+If an explicit version number is provided and
+@option{-fabi-compat-version} is not specified, the version number
+from this option is used for compatibility aliases. If no explicit
+version number is provided with this option, but
+@option{-fabi-compat-version} is specified, that version number is
+used for ABI warnings.
Although an effort has been made to warn about
all such cases, there are probably some cases that are not warned about,
@@ -2577,13 +2601,7 @@ You should rewrite your code to avoid these warnings if you are
concerned about the fact that code generated by G++ may not be binary
compatible with code generated by other compilers.
-@option{-Wabi} can also be used with an explicit version number to
-warn about compatibility with a particular @option{-fabi-version}
-level, e.g. @option{-Wabi=2} to warn about changes relative to
-@option{-fabi-version=2}. Specifying a version number also sets
-@option{-fabi-compat-version=@var{n}}.
-
-The known incompatibilities in @option{-fabi-version=2} (which was the
+Known incompatibilities in @option{-fabi-version=2} (which was the
default from GCC 3.4 to 4.9) include:
@itemize @bullet
@@ -2635,7 +2653,24 @@ When mangling a function type with function-cv-qualifiers, the
un-qualified function type was incorrectly treated as a substitution
candidate.
-This was fixed in @option{-fabi-version=8}.
+This was fixed in @option{-fabi-version=8}, the default for GCC 5.1.
+
+@item
+@code{decltype(nullptr)} incorrectly had an alignment of 1, leading to
+unaligned accesses. Note that this did not affect the ABI of a
+function with a @code{nullptr_t} parameter, as parameters have a
+minimum alignment.
+
+This was fixed in @option{-fabi-version=9}, the default for GCC 5.2.
+
+@item
+Target-specific attributes that affect the identity of a type, such as
+ia32 calling conventions on a function type (stdcall, regparm, etc.),
+did not affect the mangled name, leading to name collisions when
+function pointers were used as template arguments.
+
+This was fixed in @option{-fabi-version=10}, the default for GCC 6.1.
+
@end itemize
It also warns about psABI-related changes. The known psABI changes at this