Richard Sandiford <richard.sandiford@arm.com> writes:
> "Roger Sayle" <roger@nextmovesoftware.com> writes:
>> The recent change to represent language and target attribute tables using
>> vec.h's array_slice template class triggers an issue/bug in older g++
>> compilers, specifically the g++ 4.8.5 system compiler of older RedHat
>> distributions. This exhibits as the following compilation errors during
>> bootstrap:
>>
>> ../../gcc/gcc/c/c-lang.cc:55:2661: error: could not convert '(const
>> scoped_attribute_specs* const*)(& c_objc_attribute_table)' from 'const
>> scoped_attribute_specs* const*' to 'array_slice<const
>> scoped_attribute_specs* const>'
>> struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
>>
>> ../../gcc/gcc/c/c-decl.cc:4657:1: error: could not convert '(const
>> attribute_spec*)(& std_attributes)' from 'const attribute_spec*' to
>> 'array_slice<const attribute_spec>'
>>
>> Here the issue is with constructors of the from:
>>
>> static const int table[] = { 1, 2, 3 };
>> array_slice<int> t = table;
>
> It's array_slice<const int> rather than array_slice<int>. The above
> would be invalid even with functioning compilers.
>
>> Perhaps there's a fix possible in vec.h (an additional constructor?), but
>> the patch below fixes this issue by using one of array_slice's constructors
>> (that takes a size) explicitly, rather than rely on template resolution.
>> In the example above this looks like:
>>
>> array_slice<int> t (table, 3);
>>
>> or equivalently
>>
>> array_slice<int> t = array_slice<int>(table, 3);
>>
>> or equivalently
>>
>> array_slice<int> t = array_slice<int>(table, ARRAY_SIZE (table));
>
> Taking c-decl.cc as an arbitrary example, it seems to be enough to change:
>
> const scoped_attribute_specs std_attribute_table =
> {
> nullptr, std_attributes
> };
>
> to:
>
> const scoped_attribute_specs std_attribute_table =
> {
> nullptr, { std_attributes }
> };
>
> which seems less ugly than the explicit constructors.
>
> But if we're going to do this, we should do it across the board,
> not just for x86.
Here's an attempt to do that. Tested so far by building
aarch64-linux-gnu (which has target attributes) and frv-elf
(which doesn't) with GCC 4.8.
OK if further testing passes?
Richard
---
GCC 5 and earlier applied array-to-pointer decay too early,
which affected the new attribute namespace code. A reduced
example of the construct that the attribute code uses is:
struct S { template<__SIZE_TYPE__ N> S(int (&)[N]); };
struct T { int a; S b; };
int a[] = { 1 };
T t = { 1, a };
This was fixed by f85e1317f8ea933f5c615680353bd646f480f7d3
(PR 16333 et al).
This patch tries to add a minimally-invasive workaround.
gcc/ada/
* gcc-interface/utils.cc (gnat_internal_attribute_table): Add extra
braces to work around PR 16333 in older compilers.
gcc/
* attribs.cc (handle_ignored_attributes_option): Add extra
braces to work around PR 16333 in older compilers.
* config/arm/arm.cc (arm_gnu_attribute_table): Likewise.
* config/i386/i386-options.cc (ix86_gnu_attribute_table): Likewise.
* config/ia64/ia64.cc (ia64_gnu_attribute_table): Likewise.
* config/rs6000/rs6000.cc (rs6000_gnu_attribute_table): Likewise.
* target-def.h (TARGET_GNU_ATTRIBUTES): Likewise.
* genhooks.cc (emit_init_macros): Likewise, when emitting the
instantiation of TARGET_ATTRIBUTE_TABLE.
* langhooks-def.h (LANG_HOOKS_INITIALIZER): Likewise, when
instantiating LANG_HOOKS_ATTRIBUTE_TABLE.
(LANG_HOOKS_ATTRIBUTE_TABLE): Define to be empty by default.
* target.def (attribute_table): Likewise.
gcc/c-family/
* c-attribs.cc (c_common_gnu_attribute_table): Add extra
braces to work around PR 16333 in older compilers.
gcc/c/
* c-decl.cc (std_attribute_table): Add extra braces to work
around PR 16333 in older compilers.
gcc/cp/
* tree.cc (cxx_gnu_attribute_table): Add extra braces to work
around PR 16333 in older compilers.
gcc/d/
* d-attribs.cc (d_langhook_common_attribute_table): Add extra braces
to work around PR 16333 in older compilers.
(d_langhook_gnu_attribute_table): Likewise.
gcc/fortran/
* f95-lang.cc (gfc_gnu_attribute_table): Add extra braces to work
around PR 16333 in older compilers.
gcc/jit/
* dummy-frontend.cc (jit_gnu_attribute_table): Add extra braces
to work around PR 16333 in older compilers.
(jit_format_attribute_table): Likewise.
gcc/lto/
* lto-lang.cc (lto_gnu_attribute_table): Add extra braces to work
around PR 16333 in older compilers.
(lto_format_attribute_table): Likewise.
---
gcc/ada/gcc-interface/utils.cc | 2 +-
gcc/attribs.cc | 2 +-
gcc/c-family/c-attribs.cc | 4 ++--
gcc/c/c-decl.cc | 2 +-
gcc/config/arm/arm.cc | 2 +-
gcc/config/i386/i386-options.cc | 2 +-
gcc/config/ia64/ia64.cc | 2 +-
gcc/config/rs6000/rs6000.cc | 2 +-
gcc/cp/tree.cc | 7 +++++--
gcc/d/d-attribs.cc | 4 ++--
gcc/fortran/f95-lang.cc | 2 +-
gcc/genhooks.cc | 7 ++++++-
gcc/jit/dummy-frontend.cc | 4 ++--
gcc/langhooks-def.h | 4 ++--
gcc/lto/lto-lang.cc | 4 ++--
gcc/target-def.h | 2 +-
gcc/target.def | 2 +-
17 files changed, 31 insertions(+), 23 deletions(-)
On Mon, Dec 04, 2023 at 01:19:21PM +0000, Richard Sandiford wrote:
> >> (that takes a size) explicitly, rather than rely on template resolution.
> >> In the example above this looks like:
> >>
> >> array_slice<int> t (table, 3);
> >>
> >> or equivalently
> >>
> >> array_slice<int> t = array_slice<int>(table, 3);
> >>
> >> or equivalently
> >>
> >> array_slice<int> t = array_slice<int>(table, ARRAY_SIZE (table));
> >
> > Taking c-decl.cc as an arbitrary example, it seems to be enough to change:
> >
> > const scoped_attribute_specs std_attribute_table =
> > {
> > nullptr, std_attributes
> > };
> >
> > to:
> >
> > const scoped_attribute_specs std_attribute_table =
> > {
> > nullptr, { std_attributes }
> > };
> >
> > which seems less ugly than the explicit constructors.
> >
> > But if we're going to do this, we should do it across the board,
> > not just for x86.
>
> Here's an attempt to do that. Tested so far by building
> aarch64-linux-gnu (which has target attributes) and frv-elf
> (which doesn't) with GCC 4.8.
>
> OK if further testing passes?
>
> Richard
>
> ---
>
> GCC 5 and earlier applied array-to-pointer decay too early,
> which affected the new attribute namespace code. A reduced
> example of the construct that the attribute code uses is:
>
> struct S { template<__SIZE_TYPE__ N> S(int (&)[N]); };
> struct T { int a; S b; };
> int a[] = { 1 };
> T t = { 1, a };
>
> This was fixed by f85e1317f8ea933f5c615680353bd646f480f7d3
> (PR 16333 et al).
>
> This patch tries to add a minimally-invasive workaround.
>
> gcc/ada/
> * gcc-interface/utils.cc (gnat_internal_attribute_table): Add extra
> braces to work around PR 16333 in older compilers.
>
> gcc/
> * attribs.cc (handle_ignored_attributes_option): Add extra
> braces to work around PR 16333 in older compilers.
> * config/arm/arm.cc (arm_gnu_attribute_table): Likewise.
> * config/i386/i386-options.cc (ix86_gnu_attribute_table): Likewise.
> * config/ia64/ia64.cc (ia64_gnu_attribute_table): Likewise.
> * config/rs6000/rs6000.cc (rs6000_gnu_attribute_table): Likewise.
> * target-def.h (TARGET_GNU_ATTRIBUTES): Likewise.
> * genhooks.cc (emit_init_macros): Likewise, when emitting the
> instantiation of TARGET_ATTRIBUTE_TABLE.
> * langhooks-def.h (LANG_HOOKS_INITIALIZER): Likewise, when
> instantiating LANG_HOOKS_ATTRIBUTE_TABLE.
> (LANG_HOOKS_ATTRIBUTE_TABLE): Define to be empty by default.
> * target.def (attribute_table): Likewise.
>
> gcc/c-family/
> * c-attribs.cc (c_common_gnu_attribute_table): Add extra
> braces to work around PR 16333 in older compilers.
>
> gcc/c/
> * c-decl.cc (std_attribute_table): Add extra braces to work
> around PR 16333 in older compilers.
>
> gcc/cp/
> * tree.cc (cxx_gnu_attribute_table): Add extra braces to work
> around PR 16333 in older compilers.
>
> gcc/d/
> * d-attribs.cc (d_langhook_common_attribute_table): Add extra braces
> to work around PR 16333 in older compilers.
> (d_langhook_gnu_attribute_table): Likewise.
>
> gcc/fortran/
> * f95-lang.cc (gfc_gnu_attribute_table): Add extra braces to work
> around PR 16333 in older compilers.
>
> gcc/jit/
> * dummy-frontend.cc (jit_gnu_attribute_table): Add extra braces
> to work around PR 16333 in older compilers.
> (jit_format_attribute_table): Likewise.
>
> gcc/lto/
> * lto-lang.cc (lto_gnu_attribute_table): Add extra braces to work
> around PR 16333 in older compilers.
> (lto_format_attribute_table): Likewise.
LGTM.
Jakub
@@ -221,7 +221,7 @@ static const attribute_spec gnat_internal_attributes[] =
const scoped_attribute_specs gnat_internal_attribute_table =
{
- "gnu", gnat_internal_attributes
+ "gnu", { gnat_internal_attributes }
};
/* Associates a GNAT tree node to a GCC tree node. It is used in
@@ -302,7 +302,7 @@ handle_ignored_attributes_option (vec<char *> *v)
attrs = { table, 1 };
}
const scoped_attribute_specs scoped_specs = {
- IDENTIFIER_POINTER (vendor_id), attrs
+ IDENTIFIER_POINTER (vendor_id), { attrs }
};
register_scoped_attributes (scoped_specs, attrs.empty ());
}
@@ -584,7 +584,7 @@ const struct attribute_spec c_common_gnu_attributes[] =
const struct scoped_attribute_specs c_common_gnu_attribute_table =
{
- "gnu", c_common_gnu_attributes
+ "gnu", { c_common_gnu_attributes }
};
/* Give the specifications for the format attributes, used by C and all
@@ -603,7 +603,7 @@ const struct attribute_spec c_common_format_attributes[] =
const struct scoped_attribute_specs c_common_format_attribute_table =
{
- "gnu", c_common_format_attributes
+ "gnu", { c_common_format_attributes }
};
/* Returns TRUE iff the attribute indicated by ATTR_ID takes a plain
@@ -4653,7 +4653,7 @@ static const attribute_spec std_attributes[] =
const scoped_attribute_specs std_attribute_table =
{
- nullptr, std_attributes
+ nullptr, { std_attributes }
};
/* Create the predefined scalar types of C,
@@ -385,7 +385,7 @@ static const attribute_spec arm_gnu_attributes[] =
static const scoped_attribute_specs arm_gnu_attribute_table =
{
- "gnu", arm_gnu_attributes
+ "gnu", { arm_gnu_attributes }
};
static const scoped_attribute_specs *const arm_attribute_table[] =
@@ -4171,7 +4171,7 @@ static const attribute_spec ix86_gnu_attributes[] =
const scoped_attribute_specs ix86_gnu_attribute_table =
{
- "gnu", ix86_gnu_attributes
+ "gnu", { ix86_gnu_attributes }
};
#include "gt-i386-options.h"
@@ -375,7 +375,7 @@ static const attribute_spec ia64_gnu_attributes[] =
static const scoped_attribute_specs ia64_gnu_attribute_table =
{
- "gnu", ia64_gnu_attributes
+ "gnu", { ia64_gnu_attributes }
};
static const scoped_attribute_specs *const ia64_attribute_table[] =
@@ -1276,7 +1276,7 @@ static const attribute_spec rs6000_gnu_attributes[] =
static const scoped_attribute_specs rs6000_gnu_attribute_table =
{
- "gnu", rs6000_gnu_attributes
+ "gnu", { rs6000_gnu_attributes }
};
static const scoped_attribute_specs *const rs6000_attribute_table[] =
@@ -5098,7 +5098,7 @@ static const attribute_spec cxx_gnu_attributes[] =
const scoped_attribute_specs cxx_gnu_attribute_table =
{
- "gnu", cxx_gnu_attributes
+ "gnu", { cxx_gnu_attributes }
};
/* Table of C++ standard attributes. */
@@ -5126,7 +5126,10 @@ static const attribute_spec std_attributes[] =
handle_contract_attribute, NULL }
};
-const scoped_attribute_specs std_attribute_table = { nullptr, std_attributes };
+const scoped_attribute_specs std_attribute_table =
+{
+ nullptr, { std_attributes }
+};
/* Handle an "init_priority" attribute; arguments as in
struct attribute_spec.handler. */
@@ -194,7 +194,7 @@ static const attribute_spec d_langhook_common_attributes[] =
const scoped_attribute_specs d_langhook_common_attribute_table =
{
- "gnu", d_langhook_common_attributes
+ "gnu", { d_langhook_common_attributes }
};
/* Table of D language attributes exposed by `gcc.attribute' UDAs. */
@@ -246,7 +246,7 @@ static const attribute_spec d_langhook_gnu_attributes[] =
const scoped_attribute_specs d_langhook_gnu_attribute_table =
{
- "gnu", d_langhook_gnu_attributes
+ "gnu", { d_langhook_gnu_attributes }
};
/* Insert the type attribute ATTRNAME with value VALUE into TYPE.
@@ -102,7 +102,7 @@ static const attribute_spec gfc_gnu_attributes[] =
static const scoped_attribute_specs gfc_gnu_attribute_table =
{
- "gnu", gfc_gnu_attributes
+ "gnu", { gfc_gnu_attributes }
};
static const scoped_attribute_specs *const gfc_attribute_table[] =
@@ -304,7 +304,12 @@ emit_init_macros (const char *docname)
name, name, hook_array[i].init);
}
if (nest == print_nest)
- printf (" %s, \\\n", name);
+ {
+ if (strcmp (name, "TARGET_ATTRIBUTE_TABLE") == 0)
+ printf (" { %s }, \\\n", name);
+ else
+ printf (" %s, \\\n", name);
+ }
}
}
}
@@ -133,7 +133,7 @@ static const attribute_spec jit_gnu_attributes[] =
static const scoped_attribute_specs jit_gnu_attribute_table =
{
- "gnu", jit_gnu_attributes
+ "gnu", { jit_gnu_attributes }
};
/* Give the specifications for the format attributes, used by C and all
@@ -151,7 +151,7 @@ static const attribute_spec jit_format_attributes[] =
static const scoped_attribute_specs jit_format_attribute_table =
{
- "gnu", jit_format_attributes
+ "gnu", { jit_format_attributes }
};
static const scoped_attribute_specs *const jit_attribute_table[] =
@@ -153,7 +153,7 @@ extern const char *lhd_get_sarif_source_language (const char *);
#define LANG_HOOKS_GET_SARIF_SOURCE_LANGUAGE lhd_get_sarif_source_language
/* Attribute hooks. */
-#define LANG_HOOKS_ATTRIBUTE_TABLE {}
+#define LANG_HOOKS_ATTRIBUTE_TABLE
/* Tree inlining hooks. */
#define LANG_HOOKS_TREE_INLINING_VAR_MOD_TYPE_P \
@@ -364,7 +364,7 @@ extern void lhd_end_section (void);
LANG_HOOKS_TYPES_COMPATIBLE_P, \
LANG_HOOKS_PRINT_ERROR_FUNCTION, \
LANG_HOOKS_TO_TARGET_CHARSET, \
- LANG_HOOKS_ATTRIBUTE_TABLE, \
+ { LANG_HOOKS_ATTRIBUTE_TABLE }, \
LANG_HOOKS_TREE_INLINING_INITIALIZER, \
LANG_HOOKS_TREE_DUMP_INITIALIZER, \
LANG_HOOKS_DECLS, \
@@ -140,7 +140,7 @@ static const attribute_spec lto_gnu_attributes[] =
static const scoped_attribute_specs lto_gnu_attribute_table =
{
- "gnu", lto_gnu_attributes
+ "gnu", { lto_gnu_attributes }
};
/* Give the specifications for the format attributes, used by C and all
@@ -158,7 +158,7 @@ static const attribute_spec lto_format_attributes[] =
static const scoped_attribute_specs lto_format_attribute_table =
{
- "gnu", lto_format_attributes
+ "gnu", { lto_format_attributes }
};
static const scoped_attribute_specs *const lto_attribute_table[] =
@@ -129,7 +129,7 @@
#define TARGET_GNU_ATTRIBUTES(NAME, ...) \
static const attribute_spec NAME##_2[] = __VA_ARGS__; \
- static const scoped_attribute_specs NAME##_1 = { "gnu", NAME##_2 }; \
+ static const scoped_attribute_specs NAME##_1 = { "gnu", { NAME##_2 } }; \
static const scoped_attribute_specs *const NAME[] = { &NAME##_1 }
#include "target-hooks-def.h"
@@ -2247,7 +2247,7 @@ TARGET_GNU_ATTRIBUTES (@var{cpu_attribute_table}, @{\n\
@{ \"@var{attributen}\", @dots{} @},\n\
@});\n\
@end smallexample",
- array_slice<const struct scoped_attribute_specs *const>, {})
+ array_slice<const struct scoped_attribute_specs *const>,)
/* Return true iff attribute NAME expects a plain identifier as its first
argument. */