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 <ja...@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,
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg,
Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
HRB 36809 (AG Nuernberg)
