| Age | Commit message (Collapse) | Author | Files | Lines |
|---|
|
|
|
WG14 agreed at this week's meeting to remove support for braces around
auto scalar initializers, as incompatible with C++ auto handling of
braced initializers; thus remove that support in GCC.
Bootstrapped with no regressions for x86_64-pc-linux-gnu.
gcc/c/
* c-parser.cc (c_parser_declaration_or_fndef): Do not allow braces
around auto initializer.
gcc/testsuite/
* gcc.dg/c2x-auto-1.c, gcc.dg/c2x-auto-3.c: Expect braces around
auto initializers to be disallowed.
|
|
|
|
|
|
As mentioned in the PR, various x86 intrinsics need to return
an uninitialized vector. Currently they use self initialization
to avoid -Wuninitialized warnings, which works fine in C, but
doesn't work in C++ where -Winit-self is enabled in -Wall.
We don't have an attribute to mark a variable as knowingly
uninitialized (the uninitialized attribute exists but means
something else, only in the -ftrivial-auto-var-init context),
and trying to suppress either -Wuninitialized or -Winit-self
inside of the _mm_undefined_ps etc. intrinsic definitions
doesn't work, one needs to currently disable through pragmas
-Wuninitialized warning at the point where _mm_undefined_ps etc.
result is actually used, but that goes against the intent of
those intrinsics.
The -Winit-self warning option actually doesn't do any warning,
all we do is record a suppression for -Winit-self if !warn_init_self
on the decl definition and later look that up in uninit pass.
The following patch changes those !warn_init_self tests which
are true only based on the command line option setting, not based
on GCC diagnostic pragma overrides to
!warning_enabled_at (DECL_SOURCE_LOCATION (decl), OPT_Winit_self)
such that it takes them into account.
2023-01-16 Jakub Jelinek <jakub@redhat.com>
PR c++/105593
gcc/c/
* c-parser.cc (c_parser_initializer): Check warning_enabled_at
at the DECL_SOURCE_LOCATION (decl) for OPT_Winit_self instead
of warn_init_self.
gcc/cp/
* decl.cc (cp_finish_decl): Check warning_enabled_at
at the DECL_SOURCE_LOCATION (decl) for OPT_Winit_self instead
of warn_init_self.
gcc/testsuite/
* c-c++-common/Winit-self3.c: New test.
* c-c++-common/Winit-self4.c: New test.
* c-c++-common/Winit-self5.c: New test.
|
|
|
|
The following testcase is miscompiled, because we shorten the division
in a case where it should not be shortened.
Divisions (and modulos) can be shortened if it is unsigned division/modulo,
or if it is signed division/modulo where we can prove the dividend will
not be the minimum signed value or divisor will not be -1, because e.g.
on sizeof(long long)==sizeof(int)*2 && __INT_MAX__ == 0x7fffffff targets
(-2147483647 - 1) / -1 is UB
but
(int) (-2147483648LL / -1LL) is not, it is -2147483648.
The primary aim of both the C and C++ FE division/modulo shortening I assume
was for the implicit integral promotions of {,signed,unsigned} {char,short}
and because at this point we have no VRP information etc., the shortening
is done if the integral promotion is from unsigned type for the divisor
or if the dividend is an integer constant other than -1.
This works fine for char/short -> int promotions when char/short have
smaller precision than int - unsigned char -> int or unsigned short -> int
will always be a positive int, so never the most negative.
Now, the C FE checks whether orig_op0 is TYPE_UNSIGNED where op0 is either
the same as orig_op0 or that promoted to int, I think that works fine,
if it isn't promoted, either the division/modulo common type will have the
same precision as op0 but then the division/modulo is unsigned and so
without UB, or it will be done in wider precision (e.g. because op1 has
wider precision), but then op0 can't be minimum signed value. Or it has
been promoted to int, but in that case it was again from narrower type and
so never minimum signed int.
But the C++ FE was checking if op0 is a NOP_EXPR from TYPE_UNSIGNED.
First of all, not sure if the operand of NOP_EXPR couldn't be non-integral
type where TYPE_UNSIGNED wouldn't be meaningful, but more importantly,
even if it is a cast from unsigned integral type, we only know it can't be
minimum signed value if it is a widening cast, if it is same precision or
narrowing cast, we know nothing.
So, the following patch for the NOP_EXPR cases checks just in case that
it is from integral type and more importantly checks it is a widening
conversion, and then next to it also allows op0 to be just unsigned,
promoted or not, as that is what the C FE will do for those cases too
and I believe it must work - either the division/modulo common type
will be that unsigned type, then we can shorten and don't need to worry
about UB, or it will be some wider signed type but then it can't be most
negative value of the wider type.
And changes both the C and C++ FEs to do the same thing, using a helper
function in c-family.
2023-01-14 Jakub Jelinek <jakub@redhat.com>
PR c++/108365
* c-common.h (may_shorten_divmod): New static inline function.
* c-typeck.cc (build_binary_op): Use may_shorten_divmod for integral
division or modulo.
* typeck.cc (cp_build_binary_op): Use may_shorten_divmod for integral
division or modulo.
* c-c++-common/pr108365.c: New test.
* g++.dg/opt/pr108365.C: New test.
* g++.dg/warn/pr108365.C: New test.
|
|
We should not directly check flag_strict_flex_arrays in the
middle end. Instead, check DECL_NOT_FLEXARRAY(array_field_decl) which is set
by C/C++ FEs according to -fstrict-flex-arrays and the corresponding
attribute attached to the array_field.
As a result, We will lose the LEVEL information of -fstrict-flex-arrays in
the middle end. -Wstrict-flex-arrays will not be able to issue such
information. update the testing cases accordingly.
gcc/ChangeLog:
* attribs.cc (strict_flex_array_level_of): Move this function to ...
* attribs.h (strict_flex_array_level_of): Remove the declaration.
* gimple-array-bounds.cc (array_bounds_checker::check_array_ref):
replace the referece to strict_flex_array_level_of with
DECL_NOT_FLEXARRAY.
* tree.cc (component_ref_size): Likewise.
gcc/c/ChangeLog:
* c-decl.cc (strict_flex_array_level_of): ... here.
gcc/testsuite/ChangeLog:
* gcc.dg/Warray-bounds-flex-arrays-1.c: Delete the level information
from the message issued by -Wstrict-flex-arrays.
* gcc.dg/Warray-bounds-flex-arrays-2.c: Likewise.
* gcc.dg/Warray-bounds-flex-arrays-3.c: Likewise.
* gcc.dg/Warray-bounds-flex-arrays-4.c: Likewise.
* gcc.dg/Warray-bounds-flex-arrays-5.c: Likewise.
* gcc.dg/Warray-bounds-flex-arrays-6.c: Likewise.
* gcc.dg/Wstrict-flex-arrays-2.c: Likewise.
* gcc.dg/Wstrict-flex-arrays-3.c: Likewise.
* gcc.dg/Wstrict-flex-arrays.c: Likewise.
|
|
|
|
[PR105972]
K&R function parameter declarations are handled by calling
recursively c_parser_declaration_or_fndef in a loop, where each such
call will add_debug_begin_stmt at the start.
Now, if the K&R function definition is not a nested function,
building_stmt_list_p () is false and so we don't emit the DEBUG_BEGIN_STMTs
anywhere, but if it is a nested function, we emit it in the containing
function at the point of the nested function definition.
As the following testcase shows, it can cause ICEs if the containing
function has var-tracking disabled but nested function has them enabled,
as the DEBUG_BEGIN_STMTs are added to the containing function which
shouldn't have them but MAY_HAVE_DEBUG_MARKER_STMTS is checked already
for the nested function, or just wrong experience in the debugger.
The following patch ensures we don't emit any such DEBUG_BEGIN_STMTs for the
K&R function parameter declarations even in nested functions.
2023-01-11 Jakub Jelinek <jakub@redhat.com>
PR c/105972
* c-parser.cc (c_parser_declaration_or_fndef): Disable debug non-bind
markers for K&R function parameter declarations of nested functions.
* gcc.dg/pr105972.c: New test.
|
|
|
|
The C rule against modifiable objects with static storage duration in
inline definitions should apply to compound literals (using the C2x
feature of storage-class specifiers for compound literals) just as to
variables. Add a call to record_inline_static for compound literals
to make sure this case is detected.
Bootstrapped with no regressions for x86_64-pc-linux-gnu.
gcc/c/
* c-decl.cc (build_compound_literal): Call record_inline_static.
gcc/testsuite/
* gcc.dg/c2x-complit-8.c: New test.
|
|
|
|
__builtin_tgmath implements <tgmath.h> semantics for integer generic
arguments that handle cases involving _FloatN / _FloatNx types as
specified in TS 18661-3 plus some defect fixes.
C2x has further changes to the semantics for <tgmath.h> macros with
such types, which should also be considered defect fixes (although
handled through the integration of TS 18661-3 in C2x rather than
through an issue tracking process). Specifically, the rules were
changed because of problems raised with using the macros with the
evaluation format types such as float_t and _Float32_t: the older
version of the rules didn't allow passing _FloatN / _FloatNx types to
the narrowing macros returning float or double, or passing float /
double / long double to the narrowing macros returning _FloatN /
_FloatNx, which was a problem with the evaluation format types which
could be either kind of type depending on the value of
FLT_EVAL_METHOD.
Thus the new rules allow cases of mixing types which were not allowed
before - which is not itself a problem for __builtin_tgmath - and, as
part of the changes, the handling of integer arguments was also
changed: if there is any _FloatNx generic argument, integer generic
arguments are treated as _Float32x (not double), while the rule about
treating integer arguments to narrowing macros returning _FloatN or
_FloatNx as _Float64 not double was removed (no longer needed now
double is a valid argument to such macros).
Implement the changes for __builtin_tgmath. (The changes also added a
rule that if any argument is _DecimalNx, integer arguments are treated
as _Decimal64x, but GCC doesn't support _DecimalNx types so nothing is
done about that.)
I have a corresponding glibc patch to update glibc test expectations
for C2x and also ensure that appropriate semantics are followed when
GCC 7 through 12 are used with <tgmath.h> (avoiding __builtin_tgmath
in cases where it doesn't match the C2x semantics).
Bootstrapped with no regressions for x86_64-pc-linux-gnu.
gcc/
* doc/extend.texi (__builtin_tgmath): Do not restate standard rule
for handling real integer types.
gcc/c/
* c-parser.cc (c_parser_postfix_expression): Handle integer
generic arguments to functions passed to __builtin_tgmath as
_Float32x if any argument has _FloatNx or _Complex _FloatNx type.
Do not handle integer arguments to some narrowing functions as
_Float64.
gcc/testsuite/
* gcc.dg/builtin-tgmath-3.c: Update expectations and add more
tests.
|
|
2022 -> 2023
|
|
|
|
Both C99 and latest C2X say that compound literal shall have an object type
(complete object type in the latter case) or array of unknown bound,
so complit with function type is invalid. When the initializer had to be
non-empty for such case, we used to diagnose it as incorrect initializer,
but with (fntype){} now allowed we just ICE on it.
The following patch diagnoses that.
2022-12-19 Jakub Jelinek <jakub@redhat.com>
PR c/108043
* c-parser.cc (c_parser_postfix_expression_after_paren_type): Diagnose
compound literals with function type.
* gcc.dg/pr108043.c: New test.
* gcc.dg/c99-complit-2.c (foo): Adjust expected diagnostics for
complit with function type.
|
|
|
|
The constraints on auto in C2x disallow use with other storage-class
specifiers unless the type is inferred from an initializer. That
includes constexpr; add the missing checks for this case (the
combination of auto, constexpr and a type specifier).
Bootstrapped with no regressions for x86_64-pc-linux-gnu.
gcc/c/
* c-decl.cc (declspecs_add_type, declspecs_add_scspec): Check for
auto, constexpr and a type used together.
gcc/testsuite/
* gcc.dg/c2x-constexpr-1.c: Do not use auto, constexpr and a type
together.
* gcc.dg/c2x-constexpr-3.c: Add tests of auto, constexpr and type
used together.
|
|
|
|
A. add the following to clarify the relationship between -Warray-bounds
and the LEVEL of -fstrict-flex-array:
By default, the trailing array of a structure will be treated as a
flexible array member by '-Warray-bounds' or '-Warray-bounds=N' if
it is declared as either a flexible array member per C99 standard
onwards ('[]'), a GCC zero-length array extension ('[0]'), or an
one-element array ('[1]'). As a result, out of bounds subscripts
or offsets into zero-length arrays or one-element arrays are not
warned by default.
You can add the option '-fstrict-flex-arrays' or
'-fstrict-flex-arrays=LEVEL' to control how this option treat
trailing array of a structure as a flexible array member.
when LEVEL<=1, no change to the default behavior.
when LEVEL=2, additional warnings will be issued for out of bounds
subscripts or offsets into one-element arrays;
when LEVEL=3, in addition to LEVEL=2, additional warnings will be
issued for out of bounds subscripts or offsets into zero-length
arrays.
B. change -Warray-bounds=2 to exclude its control on how to treat
trailing arrays as flexible array members:
'-Warray-bounds=2'
This warning level also warns about the intermediate results
of pointer arithmetic that may yield out of bounds values.
This warning level may give a larger number of false positives
and is deactivated by default.
gcc/ChangeLog:
* attribs.cc (strict_flex_array_level_of): New function.
* attribs.h (strict_flex_array_level_of): Prototype for new function.
* doc/invoke.texi: Update -Warray-bounds by specifying the impact from
-fstrict-flex-arrays. Also update -Warray-bounds=2 by eliminating its
impact on treating trailing arrays as flexible array members.
* gimple-array-bounds.cc (get_up_bounds_for_array_ref): New function.
(check_out_of_bounds_and_warn): New function.
(array_bounds_checker::check_array_ref): Update with call to the above
new functions.
* tree.cc (array_ref_flexible_size_p): Add one new argument.
(component_ref_sam_type): New function.
(component_ref_size): Control with level of strict-flex-array.
* tree.h (array_ref_flexible_size_p): Update prototype.
(enum struct special_array_member): Add two new enum values.
(component_ref_sam_type): New prototype.
gcc/c/ChangeLog:
* c-decl.cc (is_flexible_array_member_p): Call new function
strict_flex_array_level_of.
gcc/testsuite/ChangeLog:
* gcc.dg/Warray-bounds-11.c: Update warnings for -Warray-bounds=2.
* gcc.dg/Warray-bounds-flex-arrays-1.c: New test.
* gcc.dg/Warray-bounds-flex-arrays-2.c: New test.
* gcc.dg/Warray-bounds-flex-arrays-3.c: New test.
* gcc.dg/Warray-bounds-flex-arrays-4.c: New test.
* gcc.dg/Warray-bounds-flex-arrays-5.c: New test.
* gcc.dg/Warray-bounds-flex-arrays-6.c: New test.
|
|
|
|
Without this change, finish_declspecs cannot tell that whether there
was an erroneous type specified, or no type at all. This may result
in additional diagnostics for implicit ints, or missing diagnostics
for multiple types.
PR c/107805
gcc/c/
* c-decl.cc (declspecs_add_type): Propagate error_mark_bode
from type to specs.
gcc/testsuite/
* gcc.dg/pr107805-1.c: New test.
* gcc.dg/pr107805-2.c: Likewise.
|
|
|
|
gcc/c/ChangeLog:
* c-decl.cc (start_function): Set the result decl source
location to the location of the typespec.
|
|
PR analyzer/107711 reports an ICE since r13-4073-gd8aba860b34203 with
the combination of -fanalyzer and -Wunused-macros.
The issue is that in c_translation_unit::consider_macro's call to
cpp_create_reader I was passing "ident_hash" for use by the the new
reader, but that takes ownership of that hash_table, so that ident_hash
erroneously gets freed when c_translation_unit::consider_macro calls
cpp_destroy, leading to a use-after-free in -Wunused-macros, where:
(gdb) p pfile->hash_table->pfile == pfile
$23 = false
and it's instead pointing at the freed reader from consider_macro,
leading to a use-after-free ICE.
Fixed thusly.
gcc/c/ChangeLog:
PR analyzer/107711
* c-parser.cc (ana::c_translation_unit::consider_macro): Pass NULL
to cpp_create_reader, rather than ident_hash, so that the new
reader gets its own hash table.
gcc/testsuite/ChangeLog:
PR analyzer/107711
* gcc.dg/analyzer/named-constants-Wunused-macros.c: New test.
Signed-off-by: David Malcolm <dmalcolm@redhat.com>
|
|
|
|
The analyzer's file-descriptor state machine tracks the access mode of
opened files, so that it can emit -Wanalyzer-fd-access-mode-mismatch.
To do this, its symbolic execution needs to "know" the values of the
constants "O_RDONLY", "O_WRONLY", and "O_ACCMODE". Currently
analyzer/sm-fd.cc simply uses these values directly from the build-time
header files, but these are the values on the host, not those from the
target, which could be different (PR analyzer/106302).
In an earlier discussion of this issue:
https://gcc.gnu.org/pipermail/gcc/2022-June/238954.html
we talked about adding a target hook for this.
However, I've also been experimenting with extending the fd state
machine to track sockets (PR analyzer/106140). For this, it's useful to
"know" the values of the constants "SOCK_STREAM" and "SOCK_DGRAM".
Unfortunately, these seem to have many arbitrary differences from target
to target.
For example: Linux/glibc general has SOCK_STREAM == 1, SOCK_DGRAM == 2,
as does AIX, but annoyingly, e.g. Linux on MIPS has them the other way
around.
It seems to me that as the analyzer grows more ambitious modeling of the
behavior of APIs (perhaps via plugins) it's more likely that the
analyzer will need to know the values of named constants, which might
not even exist on the host.
For example, at LPC it was suggested to me that -fanalyzer could check
rules about memory management inside the Linux kernel (probably via a
plugin), but doing so involves a bunch of GFP_* flags (see PR 107472).
So rather than trying to capture all this knowledge in a target hook,
this patch attempts to get at named constant values from the user's
source code.
The patch adds an interface for frontends to call into the analyzer as
the translation unit finishes. The analyzer can then call back into the
frontend to ask about the values of the named constants it cares about
whilst the frontend's data structures are still around.
The patch implements this for the C frontend, which looks up the names
by looking for named CONST_DECLs (which handles enum values). Failing
that, it attempts to look up the values of macros but only the simplest
cases are supported (a non-traditional macro with a single CPP_NUMBER
token). It does this by building a buffer containing the macro
definition and rerunning a lexer on it.
The analyzer gracefully handles the cases where named values aren't
found (such as anything more complicated than described above).
The patch ports the analyzer to use this mechanism for "O_RDONLY",
"O_WRONLY", and "O_ACCMODE". I have successfully tested my socket patch
to also use this for "SOCK_STREAM" and "SOCK_DGRAM", so the technique
seems to work.
gcc/ChangeLog:
PR analyzer/106302
* Makefile.in (ANALYZER_OBJS): Add analyzer/analyzer-language.o.
(GTFILES): Add analyzer/analyzer-language.cc.
* doc/analyzer.texi: Document __analyzer_dump_named_constant.
gcc/analyzer/ChangeLog:
PR analyzer/106302
* analyzer-language.cc: New file.
* analyzer-language.h: New file.
* analyzer.h (get_stashed_constant_by_name): New decl.
(log_stashed_constants): New decl.
* engine.cc (impl_run_checkers): Call log_stashed_constants.
* region-model-impl-calls.cc
(region_model::impl_call_analyzer_dump_named_constant): New.
* region-model.cc (region_model::on_stmt_pre): Handle
__analyzer_dump_named_constant.
* region-model.h
(region_model::impl_call_analyzer_dump_named_constant): New decl.
* sm-fd.cc (fd_state_machine::m_O_ACCMODE): New.
(fd_state_machine::m_O_RDONLY): New.
(fd_state_machine::m_O_WRONLY): New.
(fd_state_machine::fd_state_machine): Initialize the new fields.
(fd_state_machine::get_access_mode_from_flag): Use the new fields,
rather than using the host values.
gcc/c/ChangeLog:
PR analyzer/106302
* c-parser.cc: Include "analyzer/analyzer-language.h" and "toplev.h".
(class ana::c_translation_unit): New.
(c_parser_translation_unit): Call ana::on_finish_translation_unit.
gcc/testsuite/ChangeLog:
* gcc.dg/analyzer/analyzer-decls.h
(__analyzer_dump_named_constant): New decl.
* gcc.dg/analyzer/fd-4.c (void): Likewise.
(O_ACCMODE): Define.
* gcc.dg/analyzer/fd-access-mode-enum.c: New test, based on .
* gcc.dg/analyzer/fd-5.c: ...this. Rename to...
* gcc.dg/analyzer/fd-access-mode-macros.c: ...this.
(O_ACCMODE): Define.
* gcc.dg/analyzer/fd-access-mode-target-headers.c: New test, also
based on fd-5.c.
(test_sm_fd_constants): New.
* gcc.dg/analyzer/fd-dup-1.c (O_ACCMODE): Define.
* gcc.dg/analyzer/named-constants-via-enum.c: New test.
* gcc.dg/analyzer/named-constants-via-enum-and-macro.c: New test.
* gcc.dg/analyzer/named-constants-via-macros-2.c: New test.
* gcc.dg/analyzer/named-constants-via-macros.c: New test.
Signed-off-by: David Malcolm <dmalcolm@redhat.com>
|
|
|
|
Implement C2x constexpr (a feature based on the C++ one but much more
minimal, with only constexpr variables, not functions).
I believe this implementation is fully functional for use of this
feature. However, there are several things that seem unclear about
the specification that I'll need to raise in NB comments. There are
also areas where there may be followup bug fixes because the
implementation doesn't reject some more obscure cases that ought to be
rejected: cases where a constexpr initializer for floating type meets
the constraints for a constant expression in initializers but not
those for an arithmetic constant expression (previously we haven't had
to track whether something is an arithmetic constant expression in
detail, unlike with integer constant expressions), and some cases
where a tag or struct or union member gets declared indirectly in the
declaration specifiers or declarator of a constexpr declaration, which
is not permitted (modulo lack of clarity in the specification) for
underspecified declarations in general (the cases of a declaration in
the initializer, or a tagged type being directly declared as a type
specifier, are already detected).
Cases of ambiguity in the specification include:
* Many questions (previously raised in WG14 discussions) over the rule
about what conversions do or do not involve a change of value that's
not allowed in a constexpr initializer, that aren't properly
addressed by the normative text (and where the footnote on the
subject isn't very clear either, and the examples don't necessarily
follow from the normative text). I've made a series of choices
there, that include disallowing all conversions between real and
complex types or between binary and decimal floating types in
constexpr initializers, that might not necessarily agree with how
things end up getting clarified.
The dfp.cc change also arises here, to allow quiet NaN initializers
of one DFP type to be used in a constexpr initializer for another
DFP type (as is possible for signaling NaNs) by ensuring the result
of such a conversion is properly marked as canonical (note that most
of the DFP code doesn't actually do anything with NaN payloads at
all).
* Various issues with what exactly counts as part of a declaration for
the purposes of the rule on underspecified declarations not
declaring any identifiers other than ordinary identifiers (and not
declaring more than one ordinary identifier, though the latter is
undefined behavior). These include cases where the declaration of a
struct / union / enum type appears inside typeof or alignas in the
declaration specifiers (the latter also applies with auto), or in
the declarator (e.g. an array size or in a parameter declaration).
The issues are similar to those involved in C90 DR#115 and C99 DRs
#277 and #341; the intent may not be the same in all the different
cases involved, but it's not clear that the normative wording in the
various places is sufficient to deduce the differences in intent.
* The wording about producing a compound literal constant using member
access is present in one place but another place only applies that
to named constants.
* It's not clear when a structure or union constant (a constexpr
variable or compound literal with structure or union type, or a
member with such type extracted by a series of member access
operations) can itself be used in an initializer (constexpr or
otherwise). Based on general wording for initializers not having
been changed, the working draft might only strictly allow it at
automatic storage duration (but elsewhere it would be undefined
behavior, not a constraint violation, so no diagnostic required) -
since that's the only case mentioned where a single expression of
structure or union type can be used to initialize an object of such
a type. But it definitely seems to be allowed in even constexpr
initializers at automatic storage duration - and since generally
constexpr initializers (any storage duration) are *more* constrained
than ordinary static storage duration initializers, it would seem
odd for it not to be allowed at static storage duration.
* When you do allow such initializers, it's then not entirely clear
how the constraint that constexpr pointer initializers must be null
pointer constants should be applied (given that a constexpr object
of pointer type is a null pointer but *not* a null pointer
constant). My guess would be that a constexpr struct or union
containing such a field should still be allowed as an initializer,
but the wording could be read otherwise.
* It also becomes important with constexpr exactly what kind of
constant expression an implicit zero initializer is; the wording for
default initialization only really deals with the value of the
initializer and not what kind of constant it is. In particular,
this affects whether {} is a valid constexpr initializer for a
pointer not of type void *, since the wording only talks about a
null pointer, not whether it's a null pointer *constant*. I assumed
that it should be a null pointer constant in that case.
* It's also not entirely clear whether constexpr can be used in the
declaration part of a for loop (which "shall only declare
identifiers for objects having storage class auto or register"). I
interpreted it as allowed (treating such objects as implicitly auto
just like those with no storage class specifiers), but it could also
be argued that constexpr is another storage class specifier and so
not allowed there.
Bootstrapped with no regressions for x86_64-pc-linux-gnu.
gcc/
* dfp.cc (decimal_from_binary): Convert a canonical NaN to a
canonical NaN.
gcc/c-family/
* c-common.cc (c_common_reswords): Use D_C2X instead of D_CXXONLY.
gcc/c/
* c-decl.cc (start_underspecified_init)
(finish_underspecified_init): Handle name == NULL_TREE for
compound literals.
(merge_decls): Merge C_DECL_DECLARED_CONSTEXPR.
(shadow_tag_warned): Check for constexpr.
(start_decl): Add parameter do_push.
(build_compound_literal): Set C_DECL_DECLARED_CONSTEXPR.
(grokdeclarator): Handle constexpr.
(finish_struct): Set C_TYPE_FIELDS_NON_CONSTEXPR.
(declspecs_add_scspec): Handle constexpr.
* c-parser.cc (c_token_starts_compound_literal)
(c_token_starts_declspecs, c_parser_declaration_or_fndef)
(c_parser_declspecs, c_parser_gnu_attribute_any_word)
(c_parser_compound_literal_scspecs)
(c_parser_postfix_expression_after_paren_type): Handle constexpr.
Update calls to start_init.
(c_parser_declaration_or_fndef, c_parser_initializer)
(c_parser_initval): Pass true for new argument of
convert_lvalue_to_rvalue. Call convert_lvalue_to_rvalue for
constexpr compound literals.
(c_parser_static_assert_declaration_no_semi)
(c_parser_enum_specifier, c_parser_struct_declaration)
(c_parser_alignas_specifier, c_parser_initelt, c_parser_label):
Call convert_lvalue_to_rvalue on expressions required to be
integer constant expressions.
(c_parser_omp_declare_reduction): Update call to start_init.
* c-tree.h (C_TYPE_FIELDS_NON_CONSTEXPR)
(C_DECL_DECLARED_CONSTEXPR): New macros.
(struct c_declspecs): Add constexpr_p.
(start_decl, convert_lvalue_to_rvalue, start_init): Update
prototypes.
* c-typeck.cc (require_constant_value, require_constant_elements):
Change to bool.
(require_constexpr_value, maybe_get_constexpr_init)
(constexpr_init_fits_real_type, check_constexpr_init): New.
(convert_lvalue_to_rvalue): Add new parameter for_init. Call
maybe_get_constexpr_init.
(store_init_value): Update call to digest_init.
(digest_init): Add parameters int_const_expr, arith_const_expr and
require_constexpr. Check constexpr initializers.
(constructor_top_level): Remove.
(struct initializer_stack): Remove top_level. Add
require_constexpr_value.
(start_init): Remove parameter top_level. Add parameters
init_require_constant and init_require_constexpr. Save
require_constexpr_value on stack.
(pop_init_level): Use a null pointer constant for zero initializer
of pointer initialized with {}.
(output_init_element): Update call to digest_init. Avoid passing
null pointer constants of pointer type through digest_init a
second time when initializing a constexpr object.
gcc/testsuite/
* gcc.dg/c11-keywords-1.c: Also test constexpr.
* gcc.dg/c2x-constexpr-1.c, gcc.dg/c2x-constexpr-2a.c,
gcc.dg/c2x-constexpr-2b.c, gcc.dg/c2x-constexpr-3.c,
gcc.dg/c2x-constexpr-4.c, gcc.dg/c2x-constexpr-5.c,
gcc.dg/c2x-constexpr-6.c, gcc.dg/c2x-constexpr-7.c,
gcc.dg/c2x-constexpr-8.c, gcc.dg/c2x-constexpr-9.c,
gcc.dg/dfp/c2x-constexpr-dfp-1.c,
gcc.dg/dfp/c2x-constexpr-dfp-2.c, gcc.dg/gnu2x-constexpr-1.c,
gcc.target/i386/excess-precision-11.c,
gcc.target/i386/excess-precision-12.c: New tests.
|
|
|
|
Implement C2x auto, a more restricted version of the C++ feature
(closer to GNU C __auto_type in terms of what's supported).
Since the feature is very close to GNU C __auto_type, much of the
implementation can be shared. The main differences are:
* Any prior declaration of the identifier in an outer scope is
shadowed during the initializer (whereas __auto_type leaves any such
declaration visible until the initializer ends and the scope of the
__auto_type declaration itself starts). (A prior declaration in the
same scope is undefined behavior.)
* The standard feature supports braced initializers (containing a
single expression, optionally followed by a comma).
* The standard feature disallows the declaration from declaring
anything that's not an ordinary identifier (thus, the initializer
cannot declare a tag or the members of a structure or union), while
making it undefined behavior for it to declare more than one
ordinary identifier. (For the latter, while I keep the existing
error from __auto_type in the case of more than one declarator, I
don't restrict other ordinary identifiers from being declared in
inner scopes such as GNU statement expressions. I do however
disallow defining the members of an enumeration inside the
initializer (if the enum definition has no tag, that doesn't
actually violate a constraint), to avoid an enum type becoming
accessible beyond where it would have been without auto.
(Preventing new types from escaping the initializer - thus, ensuring
that anything written with auto corresponds to something that could
have been written without auto, modulo multiple evaluation of VLA
size expressions when not using auto - is a key motivation for some
restrictions on what can be declared in the initializer.)
The rule on shadowing and restrictions on other declarations in the
initializer are actually general rules for what C2x calls
underspecified declarations, a description that covers constexpr as
well as auto (in particular, this disallows a constexpr initializer
from referencing the variable being initialized). Thus, some of the
code added for those restrictions will also be of use in implementing
C2x constexpr.
auto with a type specifier remains a storage class specifier with the
same meaning as before (i.e. a redundant storage class specifier for
use at block scope).
Note that the feature is only enabled in C2x mode (-std=c2x or
-std=gnu2x); in older modes, a declaration with auto and no type is
treated as a case of implicit int (only accepted at block scope).
Since many of the restrictions on C2x auto are specified as undefined
behavior rather than constraint violations, it would be possible to
support more features from C++ auto without requiring diagnostics (but
maybe not a good idea, if it isn't clear exactly what semantics might
be given to such a feature in a future revision of C; and
-Wc23-c2y-compat should arguably warn for any such future feature
anyway). For now the features are limited to something close to
what's supported with __auto_type, with the differences as discussed
above between the two features.
Bootstrapped with no regressions for x86_64-pc-linux-gnu.
gcc/c/
* c-decl.cc (in_underspecified_init, start_underspecified_init)
(finish_underspecified_init): New.
(shadow_tag_warned, parser_xref_tag, start_struct, start_enum):
Give errors inside initializers of underspecified declarations.
(grokdeclarator): Handle (erroneous) case of C2X auto on a
parameter.
(declspecs_add_type): Handle c2x_auto_p case.
(declspecs_add_scspec): Handle auto possibly setting c2x_auto_p in
C2X mode.
(finish_declspecs): Handle c2x_auto_p.
* c-parser.cc (c_parser_declaration_or_fndef): Handle C2X auto.
* c-tree.h (C_DECL_UNDERSPECIFIED): New macro.
(struct c_declspecs): Add c2x_auto_p.
(start_underspecified_init, finish_underspecified_init): New
prototypes.
* c-typeck.cc (build_external_ref): Give error for underspecified
declaration referenced in its initializer.
gcc/testsuite/
* gcc.dg/c2x-auto-1.c, gcc.dg/c2x-auto-2.c, gcc.dg/c2x-auto-3.c,
gcc.dg/c2x-auto-4.c, gcc.dg/gnu2x-auto-1.c: New tests.
|
|
|
|
C2x allows function prototypes to be given as (...), a prototype
meaning a variable-argument function with no named arguments. To
allow such functions to access their arguments, requirements for
va_start calls are relaxed so it ignores all but its first argument
(i.e. subsequent arguments, if any, can be arbitrary pp-token
sequences).
Implement this feature accordingly. The va_start relaxation in
<stdarg.h> is itself easy: __builtin_va_start already supports a
second argument of 0 instead of a parameter name, and calls get
converted internally to the form using 0 for that argument, so
<stdarg.h> just needs changing to use a variadic macro that passes 0
as the second argument of __builtin_va_start. (This is done only in
C2x mode, on the expectation that users of older standard would expect
unsupported uses of va_start to be diagnosed.)
For the (...) functions, it's necessary to distinguish these from
unprototyped functions, whereas previously C++ (...) functions and
unprototyped functions both used NULL TYPE_ARG_TYPES. A flag is added
to tree_type_common to mark the (...) functions; as discussed on gcc@,
doing things this way is likely to be safer for unchanged code in GCC
than adding a different form of representation in TYPE_ARG_TYPES, or
adding a flag that instead signals that the function is unprototyped.
There was previously an option
-fallow-parameterless-variadic-functions to enable support for (...)
prototypes. The support was incomplete - it treated the functions as
unprototyped, and only parsed some declarations, not e.g.
"int g (int (...));". This option is changed into a no-op ignored
option; (...) is always accepted syntactically, with a pedwarn_c11
call to given required diagnostics when appropriate. The peculiarity
of a parameter list with __attribute__ followed by '...' being
accepted with that option is removed.
Interfaces in tree.cc that create function types are adjusted to set
this flag as appropriate. It is of course possible that some existing
users of the functions to create variable-argument functions actually
wanted unprototyped functions in the no-named-argument case, rather
than functions with a (...) prototype; some such cases in c-common.cc
(for built-in functions and implicit function declarations) turn out
to need updating for that reason.
I didn't do anything to change how the C++ front end creates (...)
function types. It's very likely there are unchanged places in the
compiler that in fact turn out to need changes to work properly with
(...) function prototypes.
Target setup_incoming_varargs hooks, where they used the information
passed about the last named argument, needed updating to avoid using
that information in the (...) case. Note that apart from the x86
changes, I haven't done any testing of those target changes beyond
building cc1 to check for syntax errors. It's possible further
target-specific fixes will be needed; target maintainers should watch
out for failures of c2x-stdarg-4.c or c2x-stdarg-split-1a.c, the
execution tests, which would indicate that this feature is not working
correctly. Those tests also verify the case where there are named
arguments but the last named argument has a declaration that results
in undefined behavior in previous C standard versions, such as a type
changed by the default argument promotions.
Bootstrapped with no regressions for x86_64-pc-linux-gnu.
gcc/
* config/aarch64/aarch64.cc (aarch64_setup_incoming_varargs):
Check TYPE_NO_NAMED_ARGS_STDARG_P.
* config/alpha/alpha.cc (alpha_setup_incoming_varargs): Likewise.
* config/arc/arc.cc (arc_setup_incoming_varargs): Likewise.
* config/arm/arm.cc (arm_setup_incoming_varargs): Likewise.
* config/csky/csky.cc (csky_setup_incoming_varargs): Likewise.
* config/epiphany/epiphany.cc (epiphany_setup_incoming_varargs):
Likewise.
* config/fr30/fr30.cc (fr30_setup_incoming_varargs): Likewise.
* config/frv/frv.cc (frv_setup_incoming_varargs): Likewise.
* config/ft32/ft32.cc (ft32_setup_incoming_varargs): Likewise.
* config/i386/i386.cc (ix86_setup_incoming_varargs): Likewise.
* config/ia64/ia64.cc (ia64_setup_incoming_varargs): Likewise.
* config/loongarch/loongarch.cc
(loongarch_setup_incoming_varargs): Likewise.
* config/m32r/m32r.cc (m32r_setup_incoming_varargs): Likewise.
* config/mcore/mcore.cc (mcore_setup_incoming_varargs): Likewise.
* config/mips/mips.cc (mips_setup_incoming_varargs): Likewise.
* config/mmix/mmix.cc (mmix_setup_incoming_varargs): Likewise.
* config/nds32/nds32.cc (nds32_setup_incoming_varargs): Likewise.
* config/nios2/nios2.cc (nios2_setup_incoming_varargs): Likewise.
* config/riscv/riscv.cc (riscv_setup_incoming_varargs): Likewise.
* config/rs6000/rs6000-call.cc (setup_incoming_varargs): Likewise.
* config/sh/sh.cc (sh_setup_incoming_varargs): Likewise.
* config/visium/visium.cc (visium_setup_incoming_varargs):
Likewise.
* config/vms/vms-c.cc (vms_c_common_override_options): Do not set
flag_allow_parameterless_variadic_functions.
* doc/invoke.texi (-fallow-parameterless-variadic-functions): Do
not document option.
* function.cc (assign_parms): Call assign_parms_setup_varargs for
TYPE_NO_NAMED_ARGS_STDARG_P case.
* ginclude/stdarg.h [__STDC_VERSION__ > 201710L] (va_start): Make
variadic macro. Pass second argument of 0 to __builtin_va_start.
* target.def (setup_incoming_varargs): Update documentation.
* doc/tm.texi: Regenerate.
* tree-core.h (struct tree_type_common): Add
no_named_args_stdarg_p.
* tree-streamer-in.cc (unpack_ts_type_common_value_fields): Unpack
TYPE_NO_NAMED_ARGS_STDARG_P.
* tree-streamer-out.cc (pack_ts_type_common_value_fields): Pack
TYPE_NO_NAMED_ARGS_STDARG_P.
* tree.cc (type_cache_hasher::equal): Compare
TYPE_NO_NAMED_ARGS_STDARG_P.
(build_function_type): Add argument no_named_args_stdarg_p.
(build_function_type_list_1, build_function_type_array_1)
(reconstruct_complex_type): Update calls to build_function_type.
(stdarg_p, prototype_p): Return true for (...) functions.
(gimple_canonical_types_compatible_p): Compare
TYPE_NO_NAMED_ARGS_STDARG_P.
* tree.h (TYPE_NO_NAMED_ARGS_STDARG_P): New.
(build_function_type): Update prototype.
gcc/c-family/
* c-common.cc (def_fn_type): Call build_function_type for
zero-argument variable-argument function.
(c_common_nodes_and_builtins): Build default_function_type with
build_function_type.
* c.opt (fallow-parameterless-variadic-functions): Mark as ignored
option.
gcc/c/
* c-decl.cc (grokdeclarator): Pass
arg_info->no_named_args_stdarg_p to build_function_type.
(grokparms): Check arg_info->no_named_args_stdarg_p before
converting () to (void).
(build_arg_info): Initialize no_named_args_stdarg_p.
(get_parm_info): Set no_named_args_stdarg_p.
(start_function): Pass TYPE_NO_NAMED_ARGS_STDARG_P to
build_function_type.
(store_parm_decls): Count (...) functions as prototyped.
* c-parser.cc (c_parser_direct_declarator): Allow '...' after open
parenthesis to start parameter list.
(c_parser_parms_list_declarator): Always allow '...' with no
arguments, call pedwarn_c11 and set no_named_args_stdarg_p.
* c-tree.h (struct c_arg_info): Add field no_named_args_stdarg_p.
* c-typeck.cc (composite_type): Handle
TYPE_NO_NAMED_ARGS_STDARG_P.
(function_types_compatible_p): Compare
TYPE_NO_NAMED_ARGS_STDARG_P.
gcc/fortran/
* trans-types.cc (gfc_get_function_type): Do not use
build_varargs_function_type_vec for unprototyped function.
gcc/lto/
* lto-common.cc (compare_tree_sccs_1): Compare
TYPE_NO_NAMED_ARGS_STDARG_P.
gcc/objc/
* objc-next-runtime-abi-01.cc (build_next_objc_exception_stuff):
Use build_function_type to build type of objc_setjmp_decl.
gcc/testsuite/
* gcc.dg/c11-stdarg-1.c, gcc.dg/c11-stdarg-2.c,
gcc.dg/c11-stdarg-3.c, gcc.dg/c2x-stdarg-1.c,
gcc.dg/c2x-stdarg-2.c, gcc.dg/c2x-stdarg-3.c,
gcc.dg/c2x-stdarg-4.c, gcc.dg/gnu2x-stdarg-1.c,
gcc.dg/torture/c2x-stdarg-split-1a.c,
gcc.dg/torture/c2x-stdarg-split-1b.c: New tests.
* gcc.dg/Wold-style-definition-2.c, gcc.dg/format/sentinel-1.c:
Update expected diagnostics.
* gcc.dg/c2x-nullptr-1.c (test5): Cast unused parameter to (void).
* gcc.dg/diagnostic-token-ranges.c: Use -pedantic. Expect warning
in place of error.
|
|
Previously we've been allowing that comma only in C++ when in attribute
form (which was the reason why it has been allowed), but 5.1 allows that
even in pragma form in C/C++ (with clarifications in 5.2) and 5.2
also in Fortran (which this patch doesn't implement).
Note, for directives which take an argument (== unnamed clause),
comma is not allowed in between the directive name and the argument,
like the directive-1.c testcase shows.
2022-10-28 Jakub Jelinek <jakub@redhat.com>
gcc/c/
* c-parser.cc (c_parser_omp_all_clauses): Allow optional
comma before the first clause.
(c_parser_omp_allocate, c_parser_omp_atomic, c_parser_omp_depobj,
c_parser_omp_flush, c_parser_omp_scan_loop_body,
c_parser_omp_ordered, c_finish_omp_declare_variant,
c_parser_omp_declare_target, c_parser_omp_declare_reduction,
c_parser_omp_requires, c_parser_omp_error,
c_parser_omp_assumption_clauses): Likewise.
gcc/cp/
* parser.cc (cp_parser_omp_all_clauses): Allow optional comma
before the first clause even in pragma syntax.
(cp_parser_omp_allocate, cp_parser_omp_atomic, cp_parser_omp_depobj,
cp_parser_omp_flush, cp_parser_omp_scan_loop_body,
cp_parser_omp_ordered, cp_parser_omp_assumption_clauses,
cp_finish_omp_declare_variant, cp_parser_omp_declare_target,
cp_parser_omp_declare_reduction_exprs, cp_parser_omp_requires,
cp_parser_omp_error): Likewise.
gcc/testsuite/
* c-c++-common/gomp/directive-1.c: New test.
* c-c++-common/gomp/clauses-6.c: New test.
* c-c++-common/gomp/declare-variant-2.c (f75a): Declare.
(f75): Use f75a as variant instead of f1 and don't expect error.
* g++.dg/gomp/clause-4.C (foo): Don't expect error on comma
before first clause.
* gcc.dg/gomp/clause-2.c (foo): Likewise.
|
|
C2x adds support for enums with a fixed underlying type specified
("enum e : long long;" and similar). Implement this in the C front
end. The same representation is used for these types as in C++, with
two macros moved from cp-tree.h to c-common.h.
Such enums can have bool as the underlying type, and various C
front-end code checking for boolean types is adjusted to use a new
C_BOOLEAN_TYPE_P to handle such enums the same way as bool. (Note
that for C++ we have bug 96496 that enums with underlying type bool
don't work correctly there.)
There are various issues with the wording for such enums in the
current C2x working draft (including but not limited to wording in the
accepted paper that failed to make it into the working draft), which I
intend to raise in NB comments. I think what I've implemented and
added tests for matches the intent.
Bootstrapped with no regressions for x86_64-pc-linux-gnu.
PR c/61469
gcc/c-family/
* c-common.h (ENUM_UNDERLYING_TYPE, ENUM_FIXED_UNDERLYING_TYPE_P):
New. Moved from cp/cp-tree.h.
* c-warn.cc (warnings_for_convert_and_check): Do not consider
conversions to enum with underlying type bool to overflow.
gcc/c/
* c-convert.cc (c_convert): Handle enums with underlying boolean
type like bool.
* c-decl.cc (shadow_tag_warned): Allow shadowing declarations for
enums with enum type specifier, but give errors for storage class
specifiers, qualifiers or alignment specifiers in non-definition
declarations of such enums.
(grokdeclarator): Give error for non-definition use of type
specifier with an enum type specifier.
(parser_xref_tag): Add argument has_enum_type_specifier. Pass it
to lookup_tag and use it to set ENUM_FIXED_UNDERLYING_TYPE_P.
(xref_tag): Update call to parser_xref_tag.
(start_enum): Add argument fixed_underlying_type. Complete enum
type with a fixed underlying type given in the definition. Give
error for defining without a fixed underlying type in the
definition if one was given in a prior declaration. Do not mark
enums with fixed underlying type as packed for -fshort-enums.
Store the enum type in the_enum.
(finish_enum): Do not adjust types of values or check their range
for an enum with a fixed underlying type. Set underlying type of
enum and variants.
(build_enumerator): Check enumeration constants for enum with
fixed underlying type against that type and convert to that type.
Increment in the underlying integer type, with handling for bool.
(c_simulate_enum_decl): Update call to start_enum.
(declspecs_add_type): Set specs->enum_type_specifier_ref_p.
* c-objc-common.cc (c_get_alias_set): Use ENUM_UNDERLYING_TYPE
rather than recomputing an underlying type based on size.
* c-parser.cc (c_parser_declspecs)
(c_parser_struct_or_union_specifier, c_parser_typeof_specifier):
Set has_enum_type_specifier for type specifiers.
(c_parser_enum_specifier): Handle enum type specifiers.
(c_parser_struct_or_union_specifier): Update call to
parser_xref_tag.
(c_parser_omp_atomic): Check for boolean increment or decrement
using C_BOOLEAN_TYPE_P.
* c-tree.h (C_BOOLEAN_TYPE_P): New.
(struct c_typespec): Add has_enum_type_specifier.
(struct c_declspecs): Add enum_type_specifier_ref_p.
(struct c_enum_contents): Add enum_type.
(start_enum, parser_xref_tag): Update prototypes.
* c-typeck.cc (composite_type): Allow for enumerated types
compatible with bool.
(common_type, comptypes_internal, perform_integral_promotions):
Use ENUM_UNDERLYING_TYPE.
(parser_build_binary_op, build_unary_op, convert_for_assignment)
(c_finish_return, c_start_switch, build_binary_op): Check for
boolean types using C_BOOLEAN_TYPE_P.
gcc/cp/
* cp-tree.h (ENUM_FIXED_UNDERLYING_TYPE_P, ENUM_UNDERLYING_TYPE):
Remove. Moved to c-common.h.
gcc/testsuite/
* gcc.dg/c11-enum-4.c, gcc.dg/c11-enum-5.c, gcc.dg/c11-enum-6.c,
gcc.dg/c2x-enum-6.c, gcc.dg/c2x-enum-7.c, gcc.dg/c2x-enum-8.c,
gcc.dg/gnu2x-enum-1.c: New tests.
|
|
|
|
[PR107358]
As mentioned earlier in the C++ excess precision support mail, the following
testcase is broken with excess precision both in C and C++ (though just in C++
it was triggered in real-world code).
scalar_to_vector is called in both FEs after the excess precision promotions
(or stripping of EXCESS_PRECISION_EXPR), so we can then get invalid
diagnostics that say float vector + float involves truncation (on ia32
from long double to float).
The following patch fixes that by calling scalar_to_vector on the operands
before the excess precision promotions, let scalar_to_vector just do the
diagnostics (it does e.g. fold_for_warn so it will fold
EXCESS_PRECISION_EXPR around REAL_CST to constants etc.) but will then
do the actual conversions using the excess precision promoted operands
(so say if we have vector double + (float + float) we don't actually do
vector double + (float) ((long double) float + (long double) float)
but
vector double + (double) ((long double) float + (long double) float)
2022-10-24 Jakub Jelinek <jakub@redhat.com>
PR c++/107358
gcc/c/
* c-typeck.cc (build_binary_op): Pass operands before excess precision
promotions to scalar_to_vector call.
gcc/cp/
* typeck.cc (cp_build_binary_op): Pass operands before excess precision
promotions to scalar_to_vector call.
gcc/testsuite/
* c-c++-common/pr107358.c: New test.
* g++.dg/cpp1y/pr68180.C: Remove -fexcess-precision=fast from
dg-options.
|
|
... unless marked noreturn.
This should not get in anyone's way, but should permit the use of main()
in freestanding more easily, especially for writing test cases that
should work both in freestanding and hosted modes.
gcc/c/ChangeLog:
* c-decl.cc (finish_function): Ignore hosted when deciding
whether to implicitly return zero, but check noreturn.
* c-objc-common.cc (c_missing_noreturn_ok_p): Loosen the
requirements to just MAIN_NAME_P when hosted, or `int main'
otherwise.
gcc/cp/ChangeLog:
* cp-tree.h (DECL_MAIN_P): Move most logic, besides the hosted
check, from here...
(DECL_MAIN_ANY_P): ... to here, so that it can be reused ...
(DECL_MAIN_FREESTANDING_P): ... here, with an additional
constraint on (hosted OR return type == int)
* decl.cc (finish_function): Use DECL_MAIN_FREESTANDING_P
instead of DECL_MAIN_P, to loosen the hosted requirement, but
check noreturn, before adding implicit returns.
gcc/testsuite/ChangeLog:
* gcc.dg/noreturn-4.c: Removed.
* g++.dg/freestanding-main.C: New test.
* g++.dg/freestanding-nonint-main.C: New test.
* gcc.dg/freestanding-main.c: New test.
* gcc.dg/freestanding-nonint-main.c: New test.
|
|
|
|
The GIMPLE FE was designed to defer semantic error checking to the
GIMPLE IL verifier. But that can end up causing spurious ICEs
earlier and in fact it will report an internal error. The following
tries to improve the situation by explicitely calling into the
verifier from the parser and intructing it to not ICE but instead
zap the parsed body after an error is discovered.
PR c/107305
PR c/107306
gcc/c/
* gimple-parser.cc (c_parser_parse_gimple_body): Verify
the parsed IL and zap the body on error.
gcc/
* tree-cfg.h (verify_gimple_in_seq): Add parameter to
indicate whether to emit an ICE. Add return value.
(verify_gimple_in_cfg): Likewise.
* tree-cfg.cc (verify_gimple_in_seq): Likewise.
(verify_gimple_in_cfg): Likewise.
gcc/testsuite/
* gcc.dg/gimplefe-error-15.c: New testcase.
|
|
|
|
As noted in bug 101764, a declaration "enum tag;" is invalid in
standard C after a definition, as well as when no definition is
visible; we had a pedwarn-if-pedantic for the forward declaration
case, but were missing one for the other case. Add that missing
diagnostic (if pedantic only).
(These diagnostics will need to be appropriately conditioned when
support is added for C2x enums with fixed underlying type, since "enum
tag : type;" is OK both before and after a definition.)
Bootstrapped with no regressions for x86_64-pc-linux-gnu.
PR c/107164
gcc/c/
* c-decl.cc (shadow_tag_warned): If pedantic, diagnose "enum tag;"
with previous declaration visible.
gcc/testsuite/
* gcc.dg/c99-tag-4.c, gcc.dg/c99-tag-5.c, gcc.dg/c99-tag-6.c: New
tests.
|
|
C2x has two enhancements to enumerations: allowing enumerations whose
values do not all fit in int (similar to an existing extension), and
allowing an underlying type to be specified (as in C++). This patch
implements the first of those enhancements.
Apart from adjusting diagnostics to reflect this being a standard
feature, there are some semantics differences from the previous
extension:
* The standard feature gives all the values of such an enum the
enumerated type (while keeping type int if that can represent all
values of the enumeration), where previously GCC only gave those
values outside the range of int the enumerated type. This change
was previously requested in PR 36113; it seems unlikely that people
are depending on the detail of the previous extension that some
enumerators had different types to others depending on whether their
values could be represented as int, and this patch makes the change
to types of enumerators unconditionally (if that causes problems in
practice we could always make it conditional on C2x mode instead).
* The types *while the enumeration is being defined*, for enumerators
that can't be represented as int, are now based more directly on the
types of the expressions used, rather than a possibly different type
with the right precision constructed using c_common_type_for_size.
Again, this change is made unconditionally.
* Where overflow (or wraparound to 0, in the case of an unsigned type)
when 1 is implicitly added to determine the value of the next
enumerator was previously an error, it now results in a wider type
with the same signedness (as the while-being-defined type of the
previous enumerator) being chosen, if available.
When a type is chosen in such an overflow case, or when a type is
chosen for the underlying integer type of the enumeration, it's
possible that (unsigned) __int128 is chosen. Although C2x allows for
such types wider than intmax_t to be considered extended integer
types, we don't have various features required to do so (integer
constant suffixes; sufficient library support would also be needed to
define the associated macros for printf/scanf conversions, and
<stdint.h> typedef names would need to be defined). Thus, there are
also pedwarns for exceeding the range of intmax_t / uintmax_t, as
while in principle exceeding that range is OK, it's only OK in a
context where the relevant types meet the requirements for extended
integer types, which does not currently apply here.
Bootstrapped with no regressions for x86_64-pc-linux-gnu. Also
manually checked diagnostics for c2x-enum-3.c with -m32 to confirm the
diagnostics in that { target { ! int128 } } test are as expected.
PR c/36113
gcc/c-family/
* c-common.cc (c_common_type_for_size): Add fallback to
widest_unsigned_literal_type_node or
widest_integer_literal_type_node for precision that may not
exactly match the precision of those types.
gcc/c/
* c-decl.cc (finish_enum): If any enumerators do not fit in int,
convert all to the type of the enumeration. pedwarn if no integer
type fits all enumerators and default to
widest_integer_literal_type_node in that case. Otherwise pedwarn
for type wider than intmax_t.
(build_enumerator): pedwarn for enumerators outside the range of
uintmax_t or intmax_t, and otherwise use pedwarn_c11 for
enumerators outside the range of int. On overflow, attempt to
find a wider type that can hold the value of the next enumerator.
Do not convert value to type determined with
c_common_type_for_size.
gcc/testsuite/
* gcc.dg/c11-enum-1.c, gcc.dg/c11-enum-2.c, gcc.dg/c11-enum-3.c,
gcc.dg/c2x-enum-1.c, gcc.dg/c2x-enum-2.c, gcc.dg/c2x-enum-3.c,
gcc.dg/c2x-enum-4.c, gcc.dg/c2x-enum-5.c: New tests.
* gcc.dg/pr30260.c: Explicitly use -std=gnu11. Update expected
diagnostics.
* gcc.dg/torture/pr25183.c: Update expected diagnostics.
|
|
|
|
Here is a complete patch to add std::bfloat16_t support on
x86 (AArch64 and ARM left for later). Almost no BFmode optabs
are added by the patch, so for binops/unops it extends to SFmode
first and then truncates back to BFmode.
For {HF,SF,DF,XF,TF}mode -> BFmode conversions libgcc has implementations
of all those conversions so that we avoid double rounding, for
BFmode -> {DF,XF,TF}mode conversions to avoid growing libgcc too much
it emits BFmode -> SFmode conversion first and then converts to the even
wider mode, neither step should be imprecise.
For BFmode -> HFmode, it first emits a precise BFmode -> SFmode conversion
and then SFmode -> HFmode, because neither format is subset or superset
of the other, while SFmode is superset of both.
expr.cc then contains a -ffast-math optimization of the BF -> SF and
SF -> BF conversions if we don't optimize for space (and for the latter
if -frounding-math isn't enabled either).
For x86, perhaps truncsfbf2 optab could be defined for TARGET_AVX512BF16
but IMNSHO should FAIL if !flag_finite_math || flag_rounding_math
|| !flag_unsafe_math_optimizations, because I think the insn doesn't
raise on sNaNs, hardcodes round to nearest and flushes denormals to zero.
By default (unless x86 -fexcess-precision=16) we use float excess
precision for BFmode, so truncate only on explicit casts and assignments.
The patch introduces a single __bf16 builtin - __builtin_nansf16b,
because (__bf16) __builtin_nansf ("") will drop the sNaN into qNaN,
and uses f16b suffix instead of bf16 because there would be ambiguity on
log vs. logb - __builtin_logbf16 could be either log with bf16 suffix
or logb with f16 suffix. In other cases libstdc++ should mostly use
__builtin_*f for std::bfloat16_t overloads (we have a problem with
std::nextafter though but that one we have also for std::float16_t).
2022-10-14 Jakub Jelinek <jakub@redhat.com>
gcc/
* tree-core.h (enum tree_index): Add TI_BFLOAT16_TYPE.
* tree.h (bfloat16_type_node): Define.
* tree.cc (excess_precision_type): Promote bfloat16_type_mode
like float16_type_mode.
(build_common_tree_nodes): Initialize bfloat16_type_node if
BFmode is supported.
* expmed.h (maybe_expand_shift): Declare.
* expmed.cc (maybe_expand_shift): No longer static.
* expr.cc (convert_mode_scalar): Don't ICE on BF -> HF or HF -> BF
conversions. If there is no optab, handle BF -> {DF,XF,TF,HF}
conversions as separate BF -> SF -> {DF,XF,TF,HF} conversions, add
-ffast-math generic implementation for BF -> SF and SF -> BF
conversions.
* builtin-types.def (BT_BFLOAT16, BT_FN_BFLOAT16_CONST_STRING): New.
* builtins.def (BUILT_IN_NANSF16B): New builtin.
* fold-const-call.cc (fold_const_call): Handle CFN_BUILT_IN_NANSF16B.
* config/i386/i386.cc (classify_argument): Handle E_BCmode.
(ix86_libgcc_floating_mode_supported_p): Also return true for BFmode
for -msse2.
(ix86_mangle_type): Mangle BFmode as DF16b.
(ix86_invalid_conversion, ix86_invalid_unary_op,
ix86_invalid_binary_op): Remove.
(TARGET_INVALID_CONVERSION, TARGET_INVALID_UNARY_OP,
TARGET_INVALID_BINARY_OP): Don't redefine.
* config/i386/i386-builtins.cc (ix86_bf16_type_node): Remove.
(ix86_register_bf16_builtin_type): Use bfloat16_type_node rather than
ix86_bf16_type_node, only create it if still NULL.
* config/i386/i386-builtin-types.def (BFLOAT16): Likewise.
* config/i386/i386.md (cbranchbf4, cstorebf4): New expanders.
gcc/c-family/
* c-cppbuiltin.cc (c_cpp_builtins): If bfloat16_type_node,
predefine __BFLT16_*__ macros and for C++23 also
__STDCPP_BFLOAT16_T__. Predefine bfloat16_type_node related
macros for -fbuilding-libgcc.
* c-lex.cc (interpret_float): Handle CPP_N_BFLOAT16.
gcc/c/
* c-typeck.cc (convert_arguments): Don't promote __bf16 to
double.
gcc/cp/
* cp-tree.h (extended_float_type_p): Return true for
bfloat16_type_node.
* typeck.cc (cp_compare_floating_point_conversion_ranks): Set
extended{1,2} if mv{1,2} is bfloat16_type_node. Adjust comment.
gcc/testsuite/
* lib/target-supports.exp (check_effective_target_bfloat16,
check_effective_target_bfloat16_runtime, add_options_for_bfloat16):
New.
* gcc.dg/torture/bfloat16-basic.c: New test.
* gcc.dg/torture/bfloat16-builtin.c: New test.
* gcc.dg/torture/bfloat16-builtin-issignaling-1.c: New test.
* gcc.dg/torture/bfloat16-complex.c: New test.
* gcc.dg/torture/builtin-issignaling-1.c: Allow to be includable
from bfloat16-builtin-issignaling-1.c.
* gcc.dg/torture/floatn-basic.h: Allow to be includable from
bfloat16-basic.c.
* gcc.target/i386/vect-bfloat16-typecheck_2.c: Adjust expected
diagnostics.
* gcc.target/i386/sse2-bfloat16-scalar-typecheck.c: Likewise.
* gcc.target/i386/vect-bfloat16-typecheck_1.c: Likewise.
* g++.target/i386/bfloat_cpp_typecheck.C: Likewise.
libcpp/
* include/cpplib.h (CPP_N_BFLOAT16): Define.
* expr.cc (interpret_float_suffix): Handle bf16 and BF16 suffixes for
C++.
libgcc/
* config/i386/t-softfp (softfp_extensions): Add bfsf.
(softfp_truncations): Add tfbf xfbf dfbf sfbf hfbf.
(CFLAGS-extendbfsf2.c, CFLAGS-truncsfbf2.c, CFLAGS-truncdfbf2.c,
CFLAGS-truncxfbf2.c, CFLAGS-trunctfbf2.c, CFLAGS-trunchfbf2.c): Add
-msse2.
* config/i386/libgcc-glibc.ver (GCC_13.0.0): Export
__extendbfsf2 and __trunc{s,d,x,t,h}fbf2.
* config/i386/sfp-machine.h (_FP_NANSIGN_B): Define.
* config/i386/64/sfp-machine.h (_FP_NANFRAC_B): Define.
* config/i386/32/sfp-machine.h (_FP_NANFRAC_B): Define.
* soft-fp/brain.h: New file.
* soft-fp/truncsfbf2.c: New file.
* soft-fp/truncdfbf2.c: New file.
* soft-fp/truncxfbf2.c: New file.
* soft-fp/trunctfbf2.c: New file.
* soft-fp/trunchfbf2.c: New file.
* soft-fp/truncbfhf2.c: New file.
* soft-fp/extendbfsf2.c: New file.
libiberty/
* cp-demangle.h (D_BUILTIN_TYPE_COUNT): Increment.
* cp-demangle.c (cplus_demangle_builtin_types): Add std::bfloat16_t
entry.
(cplus_demangle_type): Demangle DF16b.
* testsuite/demangle-expected (_Z3xxxDF16b): New test.
|
|
Implement the C2x feature of storage class specifiers in compound
literals. Such storage class specifiers (static, register or
thread_local; also constexpr, but we don't yet have C2x constexpr
support implemented) can be used before the type name (not mixed with
type specifiers, unlike in declarations) and have the same semantics
and constraints as for declarations of named objects. Also allow GNU
__thread to be used, given that thread_local can be.
Bootstrapped with no regressions for x86_64-pc-linux-gnu.
gcc/c/
* c-decl.cc (build_compound_literal): Add parameter scspecs.
Handle storage class specifiers.
* c-parser.cc (c_token_starts_compound_literal)
(c_parser_compound_literal_scspecs): New.
(c_parser_postfix_expression_after_paren_type): Add parameter
scspecs. Call pedwarn_c11 for use of storage class specifiers.
Update call to build_compound_literal.
(c_parser_cast_expression, c_parser_sizeof_expression)
(c_parser_alignof_expression): Handle storage class specifiers for
compound literals. Update calls to
c_parser_postfix_expression_after_paren_type.
(c_parser_postfix_expression): Update syntax comment.
* c-tree.h (build_compound_literal): Update prototype.
* c-typeck.cc (c_mark_addressable): Diagnose taking address of
register compound literal.
gcc/testsuite/
* gcc.dg/c11-complit-1.c, gcc.dg/c11-complit-2.c,
gcc.dg/c11-complit-3.c, gcc.dg/c2x-complit-2.c,
gcc.dg/c2x-complit-3.c, gcc.dg/c2x-complit-4.c,
gcc.dg/c2x-complit-5.c, gcc.dg/c2x-complit-6.c,
gcc.dg/c2x-complit-7.c, gcc.dg/c90-complit-2.c,
gcc.dg/gnu2x-complit-1.c, gcc.dg/gnu2x-complit-2.c: New tests.
|
|
|
|
Add the following new option -fstrict-flex-arrays[=n] and a corresponding
attribute strict_flex_array to GCC:
'-fstrict-flex-arrays'
Control when to treat the trailing array of a structure as a flexible array
member for the purpose of accessing the elements of such an array.
The positive form is equivalent to '-fstrict-flex-arrays=3', which is the
strictest. A trailing array is treated as a flexible array member only when
it declared as a flexible array member per C99 standard onwards.
The negative form is equivalent to '-fstrict-flex-arrays=0', which is the
least strict. All trailing arrays of structures are treated as flexible
array members.
'-fstrict-flex-arrays=LEVEL'
Control when to treat the trailing array of a structure as a flexible array
member for the purpose of accessing the elements of such an array. The value
of LEVEL controls the level of strictness
The possible values of LEVEL are the same as for the
'strict_flex_array' attribute (*note Variable Attributes::).
You can control this behavior for a specific trailing array field
of a structure by using the variable attribute 'strict_flex_array'
attribute (*note Variable Attributes::).
'strict_flex_array (LEVEL)'
The 'strict_flex_array' attribute should be attached to the trailing
array field of a structure. It controls when to treat the trailing array
field of a structure as a flexible array member for the purposes of accessing
the elements of such an array. LEVEL must be an integer betwen 0 to 3.
LEVEL=0 is the least strict level, all trailing arrays of
structures are treated as flexible array members. LEVEL=3 is the
strictest level, only when the trailing array is declared as a
flexible array member per C99 standard onwards ('[]'), it is
treated as a flexible array member.
There are two more levels in between 0 and 3, which are provided to
support older codes that use GCC zero-length array extension
('[0]') or one-element array as flexible array members('[1]'): When
LEVEL is 1, the trailing array is treated as a flexible array member
when it is declared as either '[]', '[0]', or '[1]'; When
LEVEL is 2, the trailing array is treated as a flexible array member
when it is declared as either '[]', or '[0]'.
This attribute can be used with or without the
'-fstrict-flex-arrays'. When both the attribute and the option
present at the same time, the level of the strictness for the
specific trailing array field is determined by the attribute.
gcc/c-family/ChangeLog:
* c-attribs.cc (handle_strict_flex_array_attribute): New function.
(c_common_attribute_table): New item for strict_flex_array.
* c.opt: (fstrict-flex-arrays): New option.
(fstrict-flex-arrays=): New option.
gcc/c/ChangeLog:
* c-decl.cc (flexible_array_member_type_p): New function.
(one_element_array_type_p): Likewise.
(zero_length_array_type_p): Likewise.
(add_flexible_array_elts_to_size): Call new utility
routine flexible_array_member_type_p.
(is_flexible_array_member_p): New function.
(finish_struct): Set the new DECL_NOT_FLEXARRAY flag.
gcc/cp/ChangeLog:
* module.cc (trees_out::core_bools): Stream out new bit
decl_not_flexarray.
(trees_in::core_bools): Stream in new bit decl_not_flexarray.
gcc/ChangeLog:
* doc/extend.texi: Document strict_flex_array attribute.
* doc/invoke.texi: Document -fstrict-flex-arrays[=n] option.
* print-tree.cc (print_node): Print new bit decl_not_flexarray.
* tree-core.h (struct tree_decl_common): New bit field
decl_not_flexarray.
* tree-streamer-in.cc (unpack_ts_decl_common_value_fields): Stream
in new bit decl_not_flexarray.
* tree-streamer-out.cc (pack_ts_decl_common_value_fields): Stream
out new bit decl_not_flexarray.
* tree.cc (array_at_struct_end_p): Update it with the new bit field
decl_not_flexarray.
* tree.h (DECL_NOT_FLEXARRAY): New flag.
gcc/testsuite/ChangeLog:
* g++.dg/strict-flex-array-1.C: New test.
* gcc.dg/strict-flex-array-1.c: New test.
|
|
|
