From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out30-43.freemail.mail.aliyun.com (out30-43.freemail.mail.aliyun.com [115.124.30.43]) by sourceware.org (Postfix) with ESMTPS id 947993858C52 for ; Fri, 23 Sep 2022 09:09:52 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 947993858C52 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=linux.alibaba.com X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R641e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045168;MF=lifang_xia@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0VQWOlmI_1663924189; Received: from 30.225.81.201(mailfrom:lifang_xia@linux.alibaba.com fp:SMTPD_---0VQWOlmI_1663924189) by smtp.aliyun-inc.com; Fri, 23 Sep 2022 17:09:49 +0800 Message-ID: <82abef39-0f8b-4ec0-6145-39c083ffb24c@linux.alibaba.com> Date: Fri, 23 Sep 2022 17:09:48 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.13.0 Subject: Re: [PATCH] RISC-V: Optimize relax of GP with max_alignment. To: Nelson Chu Cc: binutils@sourceware.org, Palmer Dabbelt , Greg McGary References: <20220923064726.9639-1-lifang_xia@linux.alibaba.com> From: Lifang Xia In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-20.6 required=5.0 tests=BAYES_00,ENV_AND_HDR_SPF_MATCH,GIT_PATCH_0,KAM_DMARC_STATUS,NICE_REPLY_A,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_PASS,TXREP,UNPARSEABLE_RELAY,USER_IN_DEF_SPF_WL 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: On 2022/9/23 16:05, Nelson Chu wrote: > On Fri, Sep 23, 2022 at 2:48 PM wrote: >> From: Lifang Xia >> >> The max_alignment defined out of [gp-2K, gp+2k), the max_alignment >> shouldn't affect the relax of gp. >> If the symbol is in [gp-2K, gp+2k), the max_alignment would be >> replaced with the max_alignment of the section in [gp-2k, gp+2k). > This idea should works! But I need to pass the riscv-gnu-toolchain > regression at least, though the regression shouldn't be broken by the > change. > Btw, also cc Palmer and Greg that they may have interested in and have > some though on this. Thanks for this. And thanks for the review, I'll update the patch v2 later. > Thanks > Nelson > >> bfd/ >> * elfnn-riscv.c (_bfd_riscv_get_max_alignment_in_gp): New. >> (_bfd_riscv_relax_lui): The max_alignment of sections is from >> [gp-2K, gp+2K). >> (_bfd_riscv_relax_pc): Likewise. >> ld/ >> * ld/testsuite/ld-riscv-elf/relax-max-align.*: New tests. >> --- >> bfd/elfnn-riscv.c | 36 ++++++++++++++++ >> ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp | 1 + >> ld/testsuite/ld-riscv-elf/relax-max-align.d | 46 +++++++++++++++++++++ >> ld/testsuite/ld-riscv-elf/relax-max-align.s | 29 +++++++++++++ >> 4 files changed, 112 insertions(+) >> create mode 100644 ld/testsuite/ld-riscv-elf/relax-max-align.d >> create mode 100644 ld/testsuite/ld-riscv-elf/relax-max-align.s >> >> diff --git a/bfd/elfnn-riscv.c b/bfd/elfnn-riscv.c >> index 3d2ddf4e651..76f888d805c 100644 >> --- a/bfd/elfnn-riscv.c >> +++ b/bfd/elfnn-riscv.c >> @@ -4262,6 +4262,28 @@ _bfd_riscv_get_max_alignment (asection *sec) >> return (bfd_vma) 1 << max_alignment_power; >> } >> >> +/* Traverse all output sections in [gp-2K, gp+2K) and return the max alignment. */ >> + >> +static bfd_vma >> +_bfd_riscv_get_max_alignment_in_gp (asection *sec, bfd_vma gp) >> +{ >> + unsigned int max_alignment_power = 0; >> + asection *o; >> + >> + if (sec == NULL) >> + return 0; >> + >> + for (o = sec->output_section->owner->sections; o != NULL; o = o->next) >> + { >> + if (VALID_ITYPE_IMM (sec_addr(o) - gp) >> + || VALID_ITYPE_IMM (sec_addr(o) + o->size - gp)) >> + if (o->alignment_power > max_alignment_power) >> + max_alignment_power = o->alignment_power; >> + } > probably can use only one if rather than two. > >> + return (bfd_vma) 1 << max_alignment_power; >> +} >> + >> /* Relax non-PIC global variable references to GP-relative references. */ >> >> static bool >> @@ -4293,6 +4315,13 @@ _bfd_riscv_relax_lui (bfd *abfd, >> if (h->u.def.section->output_section == sym_sec->output_section >> && sym_sec->output_section != bfd_abs_section_ptr) >> max_alignment = (bfd_vma) 1 << sym_sec->output_section->alignment_power; >> + >> + /* Otherwise, consider the alignment of sections in [gp-2K,gp+2K). */ >> + else if (!undefined_weak){ >> + bfd_vma new_max_alignment = _bfd_riscv_get_max_alignment_in_gp (sym_sec, gp); >> + if (new_max_alignment) >> + max_alignment = new_max_alignment; >> + } >> } > if (...) > max_alignment = ... > else if (!undefined_weak) > { > /* Otherwise, ... */ > ... > } > >> /* Is the reference in range of x0 or gp? >> @@ -4559,6 +4588,13 @@ _bfd_riscv_relax_pc (bfd *abfd ATTRIBUTE_UNUSED, >> if (h->u.def.section->output_section == sym_sec->output_section >> && sym_sec->output_section != bfd_abs_section_ptr) >> max_alignment = (bfd_vma) 1 << sym_sec->output_section->alignment_power; >> + >> + /* Otherwise, consider the alignment of sections in [gp-2K,gp+2K). */ >> + else if (!undefined_weak){ >> + bfd_vma new_max_alignment = _bfd_riscv_get_max_alignment_in_gp (sym_sec, gp); >> + if (new_max_alignment) >> + max_alignment = new_max_alignment; >> + } >> } > Likewise, it is minor though. > >> /* Is the reference in range of x0 or gp? >> diff --git a/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp b/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp >> index df89e0ee68b..e53f16facfa 100644 >> --- a/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp >> +++ b/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp >> @@ -169,6 +169,7 @@ if [istarget "riscv*-*-*"] { >> run_dump_test "attr-merge-priv-spec-failed-05" >> run_dump_test "attr-merge-priv-spec-failed-06" >> run_dump_test "attr-phdr" >> + run_dump_test "relax-max-align" >> run_ld_link_tests [list \ >> [list "Weak reference 32" "-T weakref.ld -m[riscv_choose_ilp32_emul]" "" \ >> "-march=rv32i -mabi=ilp32" {weakref32.s} \ >> diff --git a/ld/testsuite/ld-riscv-elf/relax-max-align.d b/ld/testsuite/ld-riscv-elf/relax-max-align.d >> new file mode 100644 >> index 00000000000..4ba920da970 >> --- /dev/null >> +++ b/ld/testsuite/ld-riscv-elf/relax-max-align.d >> @@ -0,0 +1,46 @@ >> +#source: relax-max-align.s >> +#ld: >> +#objdump: -d >> + >> +.*:[ ]+file format .* >> + >> + >> +Disassembly of section .text: >> + >> +0+[0-9a-f]+ <_start>: >> +.*:[ ]+[0-9a-f]+[ ]+addi[ ]+.* >> +.*:[ ]+[0-9a-f]+[ ]+jal[ ]+.* >> +.*:[ ]+[0-9a-f]+[ ]+j[ ]+.* >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> +.*:[ ]+[0-9a-f]+[ ]+nop >> + >> +0+[0-9a-f]+ : >> +.*:[ ]+[0-9a-f]+[ ]+ret >> +[ ]+... >> diff --git a/ld/testsuite/ld-riscv-elf/relax-max-align.s b/ld/testsuite/ld-riscv-elf/relax-max-align.s >> new file mode 100644 >> index 00000000000..e8abe0f34a1 >> --- /dev/null >> +++ b/ld/testsuite/ld-riscv-elf/relax-max-align.s >> @@ -0,0 +1,29 @@ >> + >> +.global _start >> +_start: >> + lui a0, %hi(gdata) >> + addi a0, a0, %lo(gdata) >> + call func >> + j . >> + .size _start, . - _start >> + >> +.global func >> +.align 7 >> +func: >> + ret >> + .size func, . - func >> + >> +.data >> +padding: >> + .long 0 >> + .long 0 >> + .long 0 >> + .long 0 >> + .size padding, . - padding >> + >> +.global gdata >> +.type gdata, object >> +gdata: >> + .zero 4 >> + .size gdata, . - gdata >> + >> -- >> 2.32.1 (Apple Git-133) >>