tree: Use comdat tree_code_{type,length} even for C++11/14 [PR108634]
Commit Message
Hi!
The recent change to undo the tree_code_type/tree_code_length
excessive duplication apparently broke building the Linux kernel
plugin. While it is certainly desirable that GCC plugins are built
with the same compiler as GCC has been built and with the same options
(at least the important ones), it might be hard to arrange that,
e.g. if gcc is built using a cross-compiler but the plugin then built
natively, or GCC isn't bootstrapped for other reasons, or just as in
the kernel case they were building the plugin with -std=gnu++11 while
the bootstrapped GCC has been built without any such option and so with
whatever the compiler defaulted to.
For C++17 and later tree_code_{type,length} are UNIQUE symbols with
those assembler names, while for C++11/14 they were
_ZL14tree_code_type and _ZL16tree_code_length.
The following patch uses a comdat var for those even for C++11/14
as suggested by Maciej Cencora. Relying on weak attribute is not an
option because not all hosts support it and there are non-GNU system
compilers. While we could use it unconditionally,
I think defining a template just to make it comdat is weird, and
the compiler itself is always built with the same compiler.
Plugins, being separate shared libraries, will have a separate copy of
the arrays if they are ODR-used in the plugin, so there is not a big
deal if e.g. cc1plus uses tree_code_type while plugin uses
_ZN19tree_code_type_tmplILi0EE14tree_code_typeE or vice versa.
Tested in non-bootstrapped build with both -std=gnu++17 and -std=gnu++11,
ok for trunk if it passes full bootstrap/regtest?
2023-02-02 Jakub Jelinek <jakub@redhat.com>
PR plugins/108634
* tree-core.h (tree_code_type, tree_code_length): For C++11 or
C++14, don't declare as extern const arrays.
(tree_code_type_tmpl, tree_code_length_tmpl): New types with
static constexpr member arrays for C++11 or C++14.
* tree.h (TREE_CODE_CLASS): For C++11 or C++14 use
tree_code_type_tmpl <0>::tree_code_type instead of tree_code_type.
(TREE_CODE_LENGTH): For C++11 or C++14 use
tree_code_length_tmpl <0>::tree_code_length instead of
tree_code_length.
* tree.cc (tree_code_type, tree_code_length): Remove.
Jakub
Comments
On Thu, Feb 02, 2023 at 03:30:29PM +0100, Jakub Jelinek via Gcc-patches wrote:
> Tested in non-bootstrapped build with both -std=gnu++17 and -std=gnu++11,
> ok for trunk if it passes full bootstrap/regtest?
Bootstrapped/regtested successfully on x86_64-linux and i686-linux
(gcc 12 as stage1 compiler) and on powerpc64le-linux (gcc 4.8.5 as
stage1 compiler, testing the other paths).
> 2023-02-02 Jakub Jelinek <jakub@redhat.com>
>
> PR plugins/108634
> * tree-core.h (tree_code_type, tree_code_length): For C++11 or
> C++14, don't declare as extern const arrays.
> (tree_code_type_tmpl, tree_code_length_tmpl): New types with
> static constexpr member arrays for C++11 or C++14.
> * tree.h (TREE_CODE_CLASS): For C++11 or C++14 use
> tree_code_type_tmpl <0>::tree_code_type instead of tree_code_type.
> (TREE_CODE_LENGTH): For C++11 or C++14 use
> tree_code_length_tmpl <0>::tree_code_length instead of
> tree_code_length.
> * tree.cc (tree_code_type, tree_code_length): Remove.
Jakub
Hi!
I'd like to ping this patch, which has been successfully
bootstrapped/regtested on x86_64-linux and i686-linux:
https://gcc.gnu.org/pipermail/gcc-patches/2023-February/611180.html
- PR108634 - P3 - tree: Use comdat tree_code_{type,length} even for C++11/14
Thanks
Jakub
On Thu, Feb 02, 2023 at 03:30:29PM +0100, Jakub Jelinek via Gcc-patches wrote:
> The recent change to undo the tree_code_type/tree_code_length
> excessive duplication apparently broke building the Linux kernel
> plugin. While it is certainly desirable that GCC plugins are built
> with the same compiler as GCC has been built and with the same options
> (at least the important ones), it might be hard to arrange that,
> e.g. if gcc is built using a cross-compiler but the plugin then built
> natively, or GCC isn't bootstrapped for other reasons, or just as in
> the kernel case they were building the plugin with -std=gnu++11 while
> the bootstrapped GCC has been built without any such option and so with
> whatever the compiler defaulted to.
>
> For C++17 and later tree_code_{type,length} are UNIQUE symbols with
> those assembler names, while for C++11/14 they were
> _ZL14tree_code_type and _ZL16tree_code_length.
>
> The following patch uses a comdat var for those even for C++11/14
> as suggested by Maciej Cencora. Relying on weak attribute is not an
> option because not all hosts support it and there are non-GNU system
> compilers. While we could use it unconditionally,
> I think defining a template just to make it comdat is weird, and
> the compiler itself is always built with the same compiler.
> Plugins, being separate shared libraries, will have a separate copy of
> the arrays if they are ODR-used in the plugin, so there is not a big
> deal if e.g. cc1plus uses tree_code_type while plugin uses
> _ZN19tree_code_type_tmplILi0EE14tree_code_typeE or vice versa.
>
> Tested in non-bootstrapped build with both -std=gnu++17 and -std=gnu++11,
> ok for trunk if it passes full bootstrap/regtest?
>
> 2023-02-02 Jakub Jelinek <jakub@redhat.com>
>
> PR plugins/108634
> * tree-core.h (tree_code_type, tree_code_length): For C++11 or
> C++14, don't declare as extern const arrays.
> (tree_code_type_tmpl, tree_code_length_tmpl): New types with
> static constexpr member arrays for C++11 or C++14.
> * tree.h (TREE_CODE_CLASS): For C++11 or C++14 use
> tree_code_type_tmpl <0>::tree_code_type instead of tree_code_type.
> (TREE_CODE_LENGTH): For C++11 or C++14 use
> tree_code_length_tmpl <0>::tree_code_length instead of
> tree_code_length.
> * tree.cc (tree_code_type, tree_code_length): Remove.
>
> --- gcc/tree-core.h.jj 2023-01-27 10:51:27.575399052 +0100
> +++ gcc/tree-core.h 2023-02-02 15:06:05.048665279 +0100
> @@ -2285,19 +2285,27 @@ struct floatn_type_info {
> extern bool tree_contains_struct[MAX_TREE_CODES][64];
>
> /* Class of tree given its code. */
> -#if __cpp_inline_variables >= 201606L
> #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) TYPE,
> #define END_OF_BASE_TREE_CODES tcc_exceptional,
>
> +#if __cpp_inline_variables < 201606L
> +template <int N>
> +struct tree_code_type_tmpl {
> + static constexpr enum tree_code_class tree_code_type[] = {
> +#include "all-tree.def"
> + };
> +};
> +
> +template <int N>
> +constexpr enum tree_code_class tree_code_type_tmpl<N>::tree_code_type[];
> +#else
> constexpr inline enum tree_code_class tree_code_type[] = {
> #include "all-tree.def"
> };
> +#endif
>
> #undef DEFTREECODE
> #undef END_OF_BASE_TREE_CODES
> -#else
> -extern const enum tree_code_class tree_code_type[];
> -#endif
>
> /* Each tree code class has an associated string representation.
> These must correspond to the tree_code_class entries. */
> @@ -2305,18 +2313,27 @@ extern const char *const tree_code_class
>
> /* Number of argument-words in each kind of tree-node. */
>
> -#if __cpp_inline_variables >= 201606L
> #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) LENGTH,
> #define END_OF_BASE_TREE_CODES 0,
> +
> +#if __cpp_inline_variables < 201606L
> +template <int N>
> +struct tree_code_length_tmpl {
> + static constexpr unsigned char tree_code_length[] = {
> +#include "all-tree.def"
> + };
> +};
> +
> +template <int N>
> +constexpr unsigned char tree_code_length_tmpl<N>::tree_code_length[];
> +#else
> constexpr inline unsigned char tree_code_length[] = {
> #include "all-tree.def"
> };
> +#endif
>
> #undef DEFTREECODE
> #undef END_OF_BASE_TREE_CODES
> -#else
> -extern const unsigned char tree_code_length[];
> -#endif
>
> /* Vector of all alias pairs for global symbols. */
> extern GTY(()) vec<alias_pair, va_gc> *alias_pairs;
> --- gcc/tree.h.jj 2023-01-27 20:09:16.183970583 +0100
> +++ gcc/tree.h 2023-02-02 14:37:17.255004291 +0100
> @@ -177,7 +177,12 @@ code_helper::is_builtin_fn () const
> #define TREE_CODE_CLASS_STRING(CLASS)\
> tree_code_class_strings[(int) (CLASS)]
>
> +#if __cpp_inline_variables < 201606L
> +#define TREE_CODE_CLASS(CODE) \
> + tree_code_type_tmpl <0>::tree_code_type[(int) (CODE)]
> +#else
> #define TREE_CODE_CLASS(CODE) tree_code_type[(int) (CODE)]
> +#endif
>
> /* Nonzero if NODE represents an exceptional code. */
>
> @@ -271,7 +276,12 @@ code_helper::is_builtin_fn () const
>
> #define EXPR_P(NODE) IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (TREE_CODE (NODE)))
>
> +#if __cpp_inline_variables < 201606L
> +#define TREE_CODE_LENGTH(CODE) \
> + tree_code_length_tmpl <0>::tree_code_length[(int) (CODE)]
> +#else
> #define TREE_CODE_LENGTH(CODE) tree_code_length[(int) (CODE)]
> +#endif
>
>
> /* Helper macros for math builtins. */
> --- gcc/tree.cc.jj 2023-02-02 10:54:44.302473853 +0100
> +++ gcc/tree.cc 2023-02-02 14:20:58.712251654 +0100
> @@ -74,34 +74,6 @@ along with GCC; see the file COPYING3.
> #include "asan.h"
> #include "ubsan.h"
>
> -#if __cpp_inline_variables < 201606L
> -/* Tree code classes. */
> -
> -#define DEFTREECODE(SYM, NAME, TYPE, LENGTH) TYPE,
> -#define END_OF_BASE_TREE_CODES tcc_exceptional,
> -
> -const enum tree_code_class tree_code_type[] = {
> -#include "all-tree.def"
> -};
> -
> -#undef DEFTREECODE
> -#undef END_OF_BASE_TREE_CODES
> -
> -/* Table indexed by tree code giving number of expression
> - operands beyond the fixed part of the node structure.
> - Not used for types or decls. */
> -
> -#define DEFTREECODE(SYM, NAME, TYPE, LENGTH) LENGTH,
> -#define END_OF_BASE_TREE_CODES 0,
> -
> -const unsigned char tree_code_length[] = {
> -#include "all-tree.def"
> -};
> -
> -#undef DEFTREECODE
> -#undef END_OF_BASE_TREE_CODES
> -#endif
> -
> /* Names of tree components.
> Used for printing out the tree and error messages. */
> #define DEFTREECODE(SYM, NAME, TYPE, LEN) NAME,
On Fri, 10 Mar 2023, Jakub Jelinek wrote:
> Hi!
>
> I'd like to ping this patch, which has been successfully
> bootstrapped/regtested on x86_64-linux and i686-linux:
>
> https://gcc.gnu.org/pipermail/gcc-patches/2023-February/611180.html
> - PR108634 - P3 - tree: Use comdat tree_code_{type,length} even for C++11/14
OK.
Thanks,
Richard.
> Thanks
> Jakub
>
> On Thu, Feb 02, 2023 at 03:30:29PM +0100, Jakub Jelinek via Gcc-patches wrote:
> > The recent change to undo the tree_code_type/tree_code_length
> > excessive duplication apparently broke building the Linux kernel
> > plugin. While it is certainly desirable that GCC plugins are built
> > with the same compiler as GCC has been built and with the same options
> > (at least the important ones), it might be hard to arrange that,
> > e.g. if gcc is built using a cross-compiler but the plugin then built
> > natively, or GCC isn't bootstrapped for other reasons, or just as in
> > the kernel case they were building the plugin with -std=gnu++11 while
> > the bootstrapped GCC has been built without any such option and so with
> > whatever the compiler defaulted to.
> >
> > For C++17 and later tree_code_{type,length} are UNIQUE symbols with
> > those assembler names, while for C++11/14 they were
> > _ZL14tree_code_type and _ZL16tree_code_length.
> >
> > The following patch uses a comdat var for those even for C++11/14
> > as suggested by Maciej Cencora. Relying on weak attribute is not an
> > option because not all hosts support it and there are non-GNU system
> > compilers. While we could use it unconditionally,
> > I think defining a template just to make it comdat is weird, and
> > the compiler itself is always built with the same compiler.
> > Plugins, being separate shared libraries, will have a separate copy of
> > the arrays if they are ODR-used in the plugin, so there is not a big
> > deal if e.g. cc1plus uses tree_code_type while plugin uses
> > _ZN19tree_code_type_tmplILi0EE14tree_code_typeE or vice versa.
> >
> > Tested in non-bootstrapped build with both -std=gnu++17 and -std=gnu++11,
> > ok for trunk if it passes full bootstrap/regtest?
> >
> > 2023-02-02 Jakub Jelinek <jakub@redhat.com>
> >
> > PR plugins/108634
> > * tree-core.h (tree_code_type, tree_code_length): For C++11 or
> > C++14, don't declare as extern const arrays.
> > (tree_code_type_tmpl, tree_code_length_tmpl): New types with
> > static constexpr member arrays for C++11 or C++14.
> > * tree.h (TREE_CODE_CLASS): For C++11 or C++14 use
> > tree_code_type_tmpl <0>::tree_code_type instead of tree_code_type.
> > (TREE_CODE_LENGTH): For C++11 or C++14 use
> > tree_code_length_tmpl <0>::tree_code_length instead of
> > tree_code_length.
> > * tree.cc (tree_code_type, tree_code_length): Remove.
> >
> > --- gcc/tree-core.h.jj 2023-01-27 10:51:27.575399052 +0100
> > +++ gcc/tree-core.h 2023-02-02 15:06:05.048665279 +0100
> > @@ -2285,19 +2285,27 @@ struct floatn_type_info {
> > extern bool tree_contains_struct[MAX_TREE_CODES][64];
> >
> > /* Class of tree given its code. */
> > -#if __cpp_inline_variables >= 201606L
> > #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) TYPE,
> > #define END_OF_BASE_TREE_CODES tcc_exceptional,
> >
> > +#if __cpp_inline_variables < 201606L
> > +template <int N>
> > +struct tree_code_type_tmpl {
> > + static constexpr enum tree_code_class tree_code_type[] = {
> > +#include "all-tree.def"
> > + };
> > +};
> > +
> > +template <int N>
> > +constexpr enum tree_code_class tree_code_type_tmpl<N>::tree_code_type[];
> > +#else
> > constexpr inline enum tree_code_class tree_code_type[] = {
> > #include "all-tree.def"
> > };
> > +#endif
> >
> > #undef DEFTREECODE
> > #undef END_OF_BASE_TREE_CODES
> > -#else
> > -extern const enum tree_code_class tree_code_type[];
> > -#endif
> >
> > /* Each tree code class has an associated string representation.
> > These must correspond to the tree_code_class entries. */
> > @@ -2305,18 +2313,27 @@ extern const char *const tree_code_class
> >
> > /* Number of argument-words in each kind of tree-node. */
> >
> > -#if __cpp_inline_variables >= 201606L
> > #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) LENGTH,
> > #define END_OF_BASE_TREE_CODES 0,
> > +
> > +#if __cpp_inline_variables < 201606L
> > +template <int N>
> > +struct tree_code_length_tmpl {
> > + static constexpr unsigned char tree_code_length[] = {
> > +#include "all-tree.def"
> > + };
> > +};
> > +
> > +template <int N>
> > +constexpr unsigned char tree_code_length_tmpl<N>::tree_code_length[];
> > +#else
> > constexpr inline unsigned char tree_code_length[] = {
> > #include "all-tree.def"
> > };
> > +#endif
> >
> > #undef DEFTREECODE
> > #undef END_OF_BASE_TREE_CODES
> > -#else
> > -extern const unsigned char tree_code_length[];
> > -#endif
> >
> > /* Vector of all alias pairs for global symbols. */
> > extern GTY(()) vec<alias_pair, va_gc> *alias_pairs;
> > --- gcc/tree.h.jj 2023-01-27 20:09:16.183970583 +0100
> > +++ gcc/tree.h 2023-02-02 14:37:17.255004291 +0100
> > @@ -177,7 +177,12 @@ code_helper::is_builtin_fn () const
> > #define TREE_CODE_CLASS_STRING(CLASS)\
> > tree_code_class_strings[(int) (CLASS)]
> >
> > +#if __cpp_inline_variables < 201606L
> > +#define TREE_CODE_CLASS(CODE) \
> > + tree_code_type_tmpl <0>::tree_code_type[(int) (CODE)]
> > +#else
> > #define TREE_CODE_CLASS(CODE) tree_code_type[(int) (CODE)]
> > +#endif
> >
> > /* Nonzero if NODE represents an exceptional code. */
> >
> > @@ -271,7 +276,12 @@ code_helper::is_builtin_fn () const
> >
> > #define EXPR_P(NODE) IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (TREE_CODE (NODE)))
> >
> > +#if __cpp_inline_variables < 201606L
> > +#define TREE_CODE_LENGTH(CODE) \
> > + tree_code_length_tmpl <0>::tree_code_length[(int) (CODE)]
> > +#else
> > #define TREE_CODE_LENGTH(CODE) tree_code_length[(int) (CODE)]
> > +#endif
> >
> >
> > /* Helper macros for math builtins. */
> > --- gcc/tree.cc.jj 2023-02-02 10:54:44.302473853 +0100
> > +++ gcc/tree.cc 2023-02-02 14:20:58.712251654 +0100
> > @@ -74,34 +74,6 @@ along with GCC; see the file COPYING3.
> > #include "asan.h"
> > #include "ubsan.h"
> >
> > -#if __cpp_inline_variables < 201606L
> > -/* Tree code classes. */
> > -
> > -#define DEFTREECODE(SYM, NAME, TYPE, LENGTH) TYPE,
> > -#define END_OF_BASE_TREE_CODES tcc_exceptional,
> > -
> > -const enum tree_code_class tree_code_type[] = {
> > -#include "all-tree.def"
> > -};
> > -
> > -#undef DEFTREECODE
> > -#undef END_OF_BASE_TREE_CODES
> > -
> > -/* Table indexed by tree code giving number of expression
> > - operands beyond the fixed part of the node structure.
> > - Not used for types or decls. */
> > -
> > -#define DEFTREECODE(SYM, NAME, TYPE, LENGTH) LENGTH,
> > -#define END_OF_BASE_TREE_CODES 0,
> > -
> > -const unsigned char tree_code_length[] = {
> > -#include "all-tree.def"
> > -};
> > -
> > -#undef DEFTREECODE
> > -#undef END_OF_BASE_TREE_CODES
> > -#endif
> > -
> > /* Names of tree components.
> > Used for printing out the tree and error messages. */
> > #define DEFTREECODE(SYM, NAME, TYPE, LEN) NAME,
>
>
@@ -2285,19 +2285,27 @@ struct floatn_type_info {
extern bool tree_contains_struct[MAX_TREE_CODES][64];
/* Class of tree given its code. */
-#if __cpp_inline_variables >= 201606L
#define DEFTREECODE(SYM, NAME, TYPE, LENGTH) TYPE,
#define END_OF_BASE_TREE_CODES tcc_exceptional,
+#if __cpp_inline_variables < 201606L
+template <int N>
+struct tree_code_type_tmpl {
+ static constexpr enum tree_code_class tree_code_type[] = {
+#include "all-tree.def"
+ };
+};
+
+template <int N>
+constexpr enum tree_code_class tree_code_type_tmpl<N>::tree_code_type[];
+#else
constexpr inline enum tree_code_class tree_code_type[] = {
#include "all-tree.def"
};
+#endif
#undef DEFTREECODE
#undef END_OF_BASE_TREE_CODES
-#else
-extern const enum tree_code_class tree_code_type[];
-#endif
/* Each tree code class has an associated string representation.
These must correspond to the tree_code_class entries. */
@@ -2305,18 +2313,27 @@ extern const char *const tree_code_class
/* Number of argument-words in each kind of tree-node. */
-#if __cpp_inline_variables >= 201606L
#define DEFTREECODE(SYM, NAME, TYPE, LENGTH) LENGTH,
#define END_OF_BASE_TREE_CODES 0,
+
+#if __cpp_inline_variables < 201606L
+template <int N>
+struct tree_code_length_tmpl {
+ static constexpr unsigned char tree_code_length[] = {
+#include "all-tree.def"
+ };
+};
+
+template <int N>
+constexpr unsigned char tree_code_length_tmpl<N>::tree_code_length[];
+#else
constexpr inline unsigned char tree_code_length[] = {
#include "all-tree.def"
};
+#endif
#undef DEFTREECODE
#undef END_OF_BASE_TREE_CODES
-#else
-extern const unsigned char tree_code_length[];
-#endif
/* Vector of all alias pairs for global symbols. */
extern GTY(()) vec<alias_pair, va_gc> *alias_pairs;
@@ -177,7 +177,12 @@ code_helper::is_builtin_fn () const
#define TREE_CODE_CLASS_STRING(CLASS)\
tree_code_class_strings[(int) (CLASS)]
+#if __cpp_inline_variables < 201606L
+#define TREE_CODE_CLASS(CODE) \
+ tree_code_type_tmpl <0>::tree_code_type[(int) (CODE)]
+#else
#define TREE_CODE_CLASS(CODE) tree_code_type[(int) (CODE)]
+#endif
/* Nonzero if NODE represents an exceptional code. */
@@ -271,7 +276,12 @@ code_helper::is_builtin_fn () const
#define EXPR_P(NODE) IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (TREE_CODE (NODE)))
+#if __cpp_inline_variables < 201606L
+#define TREE_CODE_LENGTH(CODE) \
+ tree_code_length_tmpl <0>::tree_code_length[(int) (CODE)]
+#else
#define TREE_CODE_LENGTH(CODE) tree_code_length[(int) (CODE)]
+#endif
/* Helper macros for math builtins. */
@@ -74,34 +74,6 @@ along with GCC; see the file COPYING3.
#include "asan.h"
#include "ubsan.h"
-#if __cpp_inline_variables < 201606L
-/* Tree code classes. */
-
-#define DEFTREECODE(SYM, NAME, TYPE, LENGTH) TYPE,
-#define END_OF_BASE_TREE_CODES tcc_exceptional,
-
-const enum tree_code_class tree_code_type[] = {
-#include "all-tree.def"
-};
-
-#undef DEFTREECODE
-#undef END_OF_BASE_TREE_CODES
-
-/* Table indexed by tree code giving number of expression
- operands beyond the fixed part of the node structure.
- Not used for types or decls. */
-
-#define DEFTREECODE(SYM, NAME, TYPE, LENGTH) LENGTH,
-#define END_OF_BASE_TREE_CODES 0,
-
-const unsigned char tree_code_length[] = {
-#include "all-tree.def"
-};
-
-#undef DEFTREECODE
-#undef END_OF_BASE_TREE_CODES
-#endif
-
/* Names of tree components.
Used for printing out the tree and error messages. */
#define DEFTREECODE(SYM, NAME, TYPE, LEN) NAME,