From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by sourceware.org (Postfix) with ESMTPS id 04E193858C74 for ; Fri, 27 Jan 2023 13:14:13 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 04E193858C74 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=suse.de Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=suse.de Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id EE23621DEC; Fri, 27 Jan 2023 13:14:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1674825251; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=L4SftmT6yy9o5p3H0S9BetbfSEsgBxerOX/I2NmX/tI=; b=u1i9o2PD9uVfx8S7BOgxCqatxi/fKqkvq/f5I0lDK8nuAXlBov3PzptauX9BIxMSYoy/qU NpWcQCoZmBDOvE3Ss+VkZv/oa5ayEIwSROxn//BKCM4Z0SC+5wkBxm5SHiwOyVewN03kZD AnoDp3GSiGie5dXDmgZVDIl1AF9EwUw= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1674825251; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=L4SftmT6yy9o5p3H0S9BetbfSEsgBxerOX/I2NmX/tI=; b=JbDi1MNdwmv6bPTqF2NP8KGYZcemZjeJnai0ZnsWJpnPXL8+T7mHBY+9jkfgxrv9q+IgG0 F9kmgsVZZCQhjQBg== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id E08231336F; Fri, 27 Jan 2023 13:14:11 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id CYbGNiPO02PiGgAAMHmgww (envelope-from ); Fri, 27 Jan 2023 13:14:11 +0000 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable From: Richard Biener Mime-Version: 1.0 (1.0) Subject: Re: [PATCH] tree: Fix up tree_code_{length,type} Date: Fri, 27 Jan 2023 14:14:01 +0100 Message-Id: <19C6E4F4-8940-4DE4-9BC8-C28201E2C0F4@suse.de> References: <5461bdac-a26e-8988-3fdb-0dbc0e748ccb@idea> Cc: Patrick Palka , Jakub Jelinek , Jeff Law , Andrew Pinski In-Reply-To: <5461bdac-a26e-8988-3fdb-0dbc0e748ccb@idea> To: Patrick Palka via Gcc-patches X-Mailer: iPhone Mail (20C65) X-Spam-Status: No, score=-5.8 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: > Am 27.01.2023 um 13:41 schrieb Patrick Palka via Gcc-patches : >=20 > =EF=BB=BFOn Thu, 26 Jan 2023, Patrick Palka wrote: >=20 >>> On Thu, 26 Jan 2023, Jakub Jelinek wrote: >>>=20 >>> On Thu, Jan 26, 2023 at 09:45:35AM -0500, Patrick Palka via Gcc-patches w= rote: >>>>> +#define DEFTREECODE(SYM, NAME, TYPE, LENGTH) TYPE, >>>>> +#define END_OF_BASE_TREE_CODES tcc_exceptional, >>>>> + >>>>> + >>>>> /* Class of tree given its code. */ >>>>> -extern const enum tree_code_class tree_code_type[]; >>>>> +constexpr enum tree_code_class tree_code_type[] =3D { >>>>> +#include "all-tree.def" >>>>> +}; >>>>> + >>>>> +#undef DEFTREECODE >>>>> +#undef END_OF_BASE_TREE_CODES >>>>>=20 >>>>> /* Each tree code class has an associated string representation. >>>>> These must correspond to the tree_code_class entries. */ >>>>> extern const char *const tree_code_class_strings[]; >>>>>=20 >>>>> /* Number of argument-words in each kind of tree-node. */ >>>>> -extern const unsigned char tree_code_length[]; >>>>> + >>>>> +#define DEFTREECODE(SYM, NAME, TYPE, LENGTH) LENGTH, >>>>> +#define END_OF_BASE_TREE_CODES 0, >>>>> +constexpr unsigned char tree_code_length[] =3D { >>>>> +#include "all-tree.def" >>>>> +}; >>>>> + >>>>> +#undef DEFTREECODE >>>>> +#undef END_OF_BASE_TREE_CODES >>>>=20 >>>> IIUC defining these globals as non-inline constexpr gives them internal= >>>> linkage, and so each TU contains its own unique copy of these globals. >>>> This bloats cc1plus by a tiny bit and is technically an ODR violation >>>> because some inline functions such as tree_class_check also ODR-use >>>> these variables and so each defn of tree_class_check will refer to a >>>> "different" tree_code_class. Since inline variables are a C++17 >>>> feature, I guess we could fix this by defining the globals the old way >>>> before C++17 and as inline constexpr otherwise? >>>=20 >>> And I'd argue with the tiny bit. >>> In my x86_64-linux cc1plus from today, I see 193 _ZL16tree_code_length v= ars, >>> 374 bytes each, and 324 _ZL14tree_code_type vars, 1496 bytes each. >>> So, that means waste of 555016 .rodata bytes, plus being highly non-cach= e >>> friendly. >>>=20 >>> The following patch does that. >>>=20 >>> So far tested on x86_64-linux in my -O0 working tree (system gcc 12 >>> compiler) where .rodata shrunk with the patch by 928896 bytes, in last >>> stage of a bootstrapped tree (built by today's prev-gcc) where .rodata >>> shrunk by 561728 bytes (in neither case .text or most other sections >>> changed sizes) and on powerpc64le-linux --disable-bootstrap >>> (system gcc 4.8.5) to test also the non-C++17 case. >>=20 >> LGTM FWIW. On a related note I noticed the function >> tree.h:tree_operand_length is declared static and is then used in the >> non-static inline functions tree_operand_check etc, which seems to be >> also be a (harmless) ODR violation? >>=20 >> We probably should do s/static inline/inline throughout the header files >> at some point, which'd hopefully reduce the size of and speed up stage1 >> cc1plus. >=20 > Mechanically replacing uses of static inline in headers via >=20 > echo gcc/*.h gcc/*/*.h | xargs sed -i 's/^static inline/inline/g' >=20 > reduces rodata size of stage1 cc1plus by ~1.5MB and seems to make it ~2% > faster. Not bad.. Nice. Richard=20 >>=20 >>>=20 >>> Ok for trunk if it passes full bootstrap/regtest? >>>=20 >>> BTW, wonder if tree_code_type couldn't be an array of unsigned char >>> elements rather than enum tree_code_class and we'd then cast it >>> to the enum in the macro, that would shrink that array from 1496 bytes >>> to 374. Of course, that sounds like stage1 material. >>>=20 >>> 2023-01-26 Patrick Palka >>> Jakub Jelinek >>>=20 >>> * tree-core.h (tree_code_type, tree_code_length): For >>> C++17 and later, add inline keyword, otherwise don't define >>> the arrays, but declare extern arrays. >>> * tree.cc (tree_code_type, tree_code_length): Define these >>> arrays for C++14 and older. >>>=20 >>> --- gcc/tree-core.h.jj 2023-01-02 09:32:31.188158094 +0100 >>> +++ gcc/tree-core.h 2023-01-26 16:02:34.212113251 +0100 >>> @@ -2284,17 +2284,20 @@ struct floatn_type_info { >>> /* Matrix describing the structures contained in a given tree code. */ >>> extern bool tree_contains_struct[MAX_TREE_CODES][64]; >>>=20 >>> +/* Class of tree given its code. */ >>> +#if __cpp_inline_variables >=3D 201606L >>> #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) TYPE, >>> #define END_OF_BASE_TREE_CODES tcc_exceptional, >>>=20 >>> - >>> -/* Class of tree given its code. */ >>> -constexpr enum tree_code_class tree_code_type[] =3D { >>> +constexpr inline enum tree_code_class tree_code_type[] =3D { >>> #include "all-tree.def" >>> }; >>>=20 >>> #undef DEFTREECODE >>> #undef END_OF_BASE_TREE_CODES >>> +#else >>> +extern const enum tree_code_class tree_code_type[]; >>> +#endif >>>=20 >>> /* Each tree code class has an associated string representation. >>> These must correspond to the tree_code_class entries. */ >>> @@ -2302,14 +2305,18 @@ extern const char *const tree_code_class >>>=20 >>> /* Number of argument-words in each kind of tree-node. */ >>>=20 >>> +#if __cpp_inline_variables >=3D 201606L >>> #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) LENGTH, >>> #define END_OF_BASE_TREE_CODES 0, >>> -constexpr unsigned char tree_code_length[] =3D { >>> +constexpr inline unsigned char tree_code_length[] =3D { >>> #include "all-tree.def" >>> }; >>>=20 >>> #undef DEFTREECODE >>> #undef END_OF_BASE_TREE_CODES >>> +#else >>> +extern const unsigned char tree_code_length[]; >>> +#endif >>>=20 >>> /* Vector of all alias pairs for global symbols. */ >>> extern GTY(()) vec *alias_pairs; >>> --- gcc/tree.cc.jj 2023-01-13 17:37:45.259482663 +0100 >>> +++ gcc/tree.cc 2023-01-26 16:03:59.796878082 +0100 >>> @@ -74,7 +74,33 @@ along with GCC; see the file COPYING3. >>> #include "asan.h" >>> #include "ubsan.h" >>>=20 >>> +#if __cpp_inline_variables < 201606L >>> +/* Tree code classes. */ >>>=20 >>> +#define DEFTREECODE(SYM, NAME, TYPE, LENGTH) TYPE, >>> +#define END_OF_BASE_TREE_CODES tcc_exceptional, >>> + >>> +const enum tree_code_class tree_code_type[] =3D { >>> +#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[] =3D { >>> +#include "all-tree.def" >>> +}; >>> + >>> +#undef DEFTREECODE >>> +#undef END_OF_BASE_TREE_CODES >>> +#endif >>>=20 >>> /* Names of tree components. >>> Used for printing out the tree and error messages. */ >>>=20 >>> Jakub >>>=20 >>>=20 >>=20 >=20