From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pj1-x1032.google.com (mail-pj1-x1032.google.com [IPv6:2607:f8b0:4864:20::1032]) by sourceware.org (Postfix) with ESMTPS id AF0613858C50 for ; Tue, 22 Nov 2022 16:19:08 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org AF0613858C50 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=rivosinc.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=rivosinc.com Received: by mail-pj1-x1032.google.com with SMTP id q96-20020a17090a1b6900b00218b8f9035cso5584708pjq.5 for ; Tue, 22 Nov 2022 08:19:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20210112.gappssmtp.com; s=20210112; h=content-transfer-encoding:mime-version:message-id:to:from:cc :in-reply-to:subject:date:from:to:cc:subject:date:message-id :reply-to; bh=wefNDkbukjA5mF24XsWSNt3XiX70Taj33MCSLs5KDmo=; b=LxQDU2LoTqdSRHa7h9rqvmaAU44mHRO3Sb/JdaE79zlpi/Cc3E2VkOnmLi0nJGXUxT 5QP9Hx/7VAxEd/VLVo9CFbR4Q2JLJNDOX+E7jtlX9mwWZqc2dm1eTT7DEmjoxXtD4/6w T7MgeAWEZmEAHhWMY9Vme0BBRL2k/HEJXaH94OxXURiMdzp77Sqbao0roe07umVPOzfU iXsF/Yi017Ua75reApdMP0aVykm4qPvojb0kRkm4MeEEH2X5hfOp0/BC1ZFyPOY7T5gU JRrKnZMlVp0ZxyVpRV6I7Yt5LMHlbhjT3N4tdL+LHsZrb+QKefke6tAhXpIgAdOIK5RG Seqw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:to:from:cc :in-reply-to:subject:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=wefNDkbukjA5mF24XsWSNt3XiX70Taj33MCSLs5KDmo=; b=ba7yAps+PEPUdW46vNLlvTe8/Zg3SGXgcbXY25Jz4YhInFP9kQZOs1o3NFzGVxVpoI 2zPfGcmIz0aOIdzrYjmEbycIJntktnhpZVPnm42mObPGeF1yDV63m8geEzW16bP8LhiC mK//aJFOmIvmlj3BeeDhJcRtLCIvzb/UHnEFRO/YO/Bj0DJbV1tEgo3QKaED8HXuGcns UvrMGcPBnRyWkbO/+aQ+MVSsHVP/XVtDFr8nWr/T/Txexieol9fvU/LhB373Ilk5lV2M kMrfSNmChrem/kNpmCmwvSx0iiM+nHpRVQdhNu+BzCyu7JNydT8C2tAIFYvE6tmFRKxn mqig== X-Gm-Message-State: ANoB5pniFdM7I4wOKqsXvEDtRIA6RRdXcwXF0m+hnazvGv+tr9GcpPjB WU3eaR4dPCtnJ16e3WWSl9MXIg== X-Google-Smtp-Source: AA0mqf6QTGX5jhyz2SJXki+fsU3XbXKX4vQ0JQpnuPM02ct+8yM/9WdkYegGWQg4d6N9+QdDtlP15w== X-Received: by 2002:a17:902:f10c:b0:187:2721:68e1 with SMTP id e12-20020a170902f10c00b00187272168e1mr4972982plb.21.1669133947095; Tue, 22 Nov 2022 08:19:07 -0800 (PST) Received: from localhost ([135.180.226.51]) by smtp.gmail.com with ESMTPSA id 131-20020a621689000000b00545f5046372sm10770404pfw.208.2022.11.22.08.19.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Nov 2022 08:19:06 -0800 (PST) Date: Tue, 22 Nov 2022 08:19:06 -0800 (PST) X-Google-Original-Date: Tue, 22 Nov 2022 08:19:04 PST (-0800) Subject: Re: [PATCH v2] RISC-V: Optimize relax of GP/call with max_alignment. In-Reply-To: CC: lifang_xia@linux.alibaba.com, binutils@sourceware.org, Greg McGary From: Palmer Dabbelt To: nelson@rivosinc.com Message-ID: Mime-Version: 1.0 (MHng) Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-11.8 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,GIT_PATCH_0,RCVD_IN_DNSWL_NONE,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: On Tue, 22 Nov 2022 02:19:00 PST (-0800), nelson@rivosinc.com wrote: > On Thu, Oct 27, 2022 at 11:19 AM 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). >> >> Likewise, the max_alignment defined out of [call-1M, call+1M), >> the max_alignment shouldn't affect the relax of call. >> If the symbol is in [call-1M, call+1M), the max_alignment would be >> replaced with the max_alignment of the section in [call-1M, call+1M). > > I'm thinking that - If it is safe enough to decide which output > section alignments should be considered in the range of gp/pc, but the > target symbols or the gp are ABS symbols. If one of them is ABS, then > that means the output sections in the range of pc/gp may be different > in the different relax rounds. So maybe we should, > 1. make sure the target symbol and gp/pc are not ABS symbols, they > should belong to a section. > 2. consider the maximum output section alignment between the output > sections of the target symbol and gp/pc. > 3. Otherwise, consider all output section alignments as usual. It's actually a bit screwier than that, we also have to contend with the psABI's mixing of "PC relative" and "position independent". I've got a bug on this: https://sourceware.org/bugzilla/show_bug.cgi?id=28789 > > Thanks > Nelson > >> bfd/ >> * elfnn-riscv.c (_bfd_riscv_get_max_alignment_in_jtype): New. >> (_bfd_riscv_relax_call): The max_alignment of sections is from >> [base-1M, base+1M). >> (_bfd_riscv_get_max_alignment_in_itype): 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-call.*: New tests. >> * ld/testsuite/ld-riscv-elf/relax-max-align-gp.*: New tests. >> --- >> bfd/elfnn-riscv.c | 67 +++++++++++++++++++ >> ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp | 2 + >> .../ld-riscv-elf/relax-max-align-call.d | 18 +++++ >> .../ld-riscv-elf/relax-max-align-call.ld | 22 ++++++ >> .../ld-riscv-elf/relax-max-align-call.s | 23 +++++++ >> .../ld-riscv-elf/relax-max-align-gp.d | 46 +++++++++++++ >> .../ld-riscv-elf/relax-max-align-gp.s | 29 ++++++++ >> 7 files changed, 207 insertions(+) >> create mode 100644 ld/testsuite/ld-riscv-elf/relax-max-align-call.d >> create mode 100644 ld/testsuite/ld-riscv-elf/relax-max-align-call.ld >> create mode 100644 ld/testsuite/ld-riscv-elf/relax-max-align-call.s >> create mode 100644 ld/testsuite/ld-riscv-elf/relax-max-align-gp.d >> create mode 100644 ld/testsuite/ld-riscv-elf/relax-max-align-gp.s >> >> diff --git a/bfd/elfnn-riscv.c b/bfd/elfnn-riscv.c >> index cf852636c9c..ed72704bd80 100644 >> --- a/bfd/elfnn-riscv.c >> +++ b/bfd/elfnn-riscv.c >> @@ -4266,6 +4266,28 @@ typedef bool (*relax_func_t) (bfd *, asection *, asection *, >> riscv_pcgp_relocs *, >> bool undefined_weak); >> >> +/* Traverse all output sections in jtype, and return the max alignment. */ >> + >> +static bfd_vma >> +_bfd_riscv_get_max_alignment_in_jtype (asection *sec, bfd_vma base) >> +{ >> + unsigned int max_alignment_power = 0; >> + asection *o; >> + >> + if (sec == NULL) >> + return 0; >> + >> + for (o = sec->owner->sections; o != NULL; o = o->next) >> + { >> + if (VALID_JTYPE_IMM (sec_addr(o) - base) >> + || VALID_ITYPE_IMM (sec_addr(o) + o->size - base)) > > Probably should be JTYPE? > > >> + if (o->alignment_power > max_alignment_power) >> + max_alignment_power = o->alignment_power; >> + } >> + >> + return (bfd_vma) 1 << max_alignment_power; >> +} >> + >> /* Relax AUIPC + JALR into JAL. */ >> >> static bool >> @@ -4294,6 +4316,15 @@ _bfd_riscv_relax_call (bfd *abfd, asection *sec, asection *sym_sec, >> if (sym_sec->output_section == sec->output_section >> && sym_sec->output_section != bfd_abs_section_ptr) >> max_alignment = (bfd_vma) 1 << sym_sec->output_section->alignment_power; >> + else >> + { >> + bfd_vma new_max_alignment = >> + _bfd_riscv_get_max_alignment_in_jtype (sec, >> + (sec_addr (sec) >> + + rel->r_offset)); >> + if (new_max_alignment) >> + max_alignment = new_max_alignment; >> + } >> foff += ((bfd_signed_vma) foff < 0 ? -max_alignment : max_alignment); >> } >> >> @@ -4360,6 +4391,28 @@ _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_itype (asection *sec, bfd_vma gp) >> +{ >> + unsigned int max_alignment_power = 0; >> + asection *o; >> + >> + if (sec == NULL) >> + return 0; >> + >> + for (o = sec->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; >> + } >> + >> + return (bfd_vma) 1 << max_alignment_power; >> +} >> + >> >> /* Relax non-PIC global variable references to GP-relative references. */ >> >> static bool >> @@ -4391,6 +4444,13 @@ _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; >> + else >> + { >> + /* Otherwise, consider the alignment of sections in [gp-2K,gp+2K). */ >> + bfd_vma new_max_alignment = _bfd_riscv_get_max_alignment_in_itype (sec, gp); >> + if (new_max_alignment) >> + max_alignment = new_max_alignment; >> + } >> } >> >> /* Is the reference in range of x0 or gp? >> @@ -4656,6 +4716,13 @@ _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; >> + else if (!undefined_weak) >> + { >> + /* Otherwise, consider the alignment of sections in [gp-2K,gp+2K). */ >> + bfd_vma new_max_alignment = _bfd_riscv_get_max_alignment_in_itype (sec, gp); >> + if (new_max_alignment) >> + max_alignment = new_max_alignment; >> + } >> } >> >> /* 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..f38807b991e 100644 >> --- a/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp >> +++ b/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp >> @@ -169,6 +169,8 @@ 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-gp" >> + run_dump_test "relax-max-align-call" >> 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-call.d b/ld/testsuite/ld-riscv-elf/relax-max-align-call.d >> new file mode 100644 >> index 00000000000..490ad8c865e >> --- /dev/null >> +++ b/ld/testsuite/ld-riscv-elf/relax-max-align-call.d >> @@ -0,0 +1,18 @@ >> +#source: relax-max-align-call.s >> +#as: -march=rv64gc >> +#ld: -Trelax-max-align-call.ld >> +#objdump: -d >> + >> +.*:[ ]+file format .* >> + >> + >> +Disassembly of section .text1: >> + >> +0000000000100000 <_start>: >> +[ ]+100000:[ ]+79dff0ef[ ]+jal[ ]+1fff9c >> +[ ]+100004:[ ]+a001[ ]+j[ ]+100004 <_start\+0x4> >> + >> +Disassembly of section .text2: >> + >> +00000000001fff9c : >> +[ ]+1fff9c:[ ]+8082[ ]+ret >> diff --git a/ld/testsuite/ld-riscv-elf/relax-max-align-call.ld b/ld/testsuite/ld-riscv-elf/relax-max-align-call.ld >> new file mode 100644 >> index 00000000000..91991ed0f41 >> --- /dev/null >> +++ b/ld/testsuite/ld-riscv-elf/relax-max-align-call.ld >> @@ -0,0 +1,22 @@ >> + >> +ENTRY(_start) >> + >> +SECTIONS >> +{ >> + . = 0x100000; >> + >> + .text1 : { >> + *(.text1) >> + } >> + >> + . = 0x200000 - 100; >> + >> + .text2 : { >> + *(.text2) >> + } >> + >> + . = 0x300000; >> + .data : { >> + *(.data) >> + } >> +} >> diff --git a/ld/testsuite/ld-riscv-elf/relax-max-align-call.s b/ld/testsuite/ld-riscv-elf/relax-max-align-call.s >> new file mode 100644 >> index 00000000000..3335c0970e7 >> --- /dev/null >> +++ b/ld/testsuite/ld-riscv-elf/relax-max-align-call.s >> @@ -0,0 +1,23 @@ >> + >> +.section .text1, "ax" >> +.global _start >> +.align 2 >> +_start: >> + call foo >> + j . >> + .size _start, . - _start >> + >> +.section .text2, "ax" >> +.align 2 >> +.global foo >> +.type foo, @function >> +foo: >> + ret >> + .size foo, . - foo >> + >> +.data >> +.global gdata >> +.align 10 >> +gdata: >> + .long 0 >> + .size gdata, . - gdata >> diff --git a/ld/testsuite/ld-riscv-elf/relax-max-align-gp.d b/ld/testsuite/ld-riscv-elf/relax-max-align-gp.d >> new file mode 100644 >> index 00000000000..637de426ee4 >> --- /dev/null >> +++ b/ld/testsuite/ld-riscv-elf/relax-max-align-gp.d >> @@ -0,0 +1,46 @@ >> +#source: relax-max-align-gp.s >> +#ld: >> +#objdump: -d >> + >> +.*:[ ]+file format .* >> + >> + >> +Disassembly of section .text: >> + >> +0+[0-9a-f]+ <_start>: >> +.*:[ ]+[0-9a-f]+[ ]+add[ ]+.* >> +.*:[ ]+[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-gp.s b/ld/testsuite/ld-riscv-elf/relax-max-align-gp.s >> new file mode 100644 >> index 00000000000..0d162ff4d93 >> --- /dev/null >> +++ b/ld/testsuite/ld-riscv-elf/relax-max-align-gp.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 >> + >> -- >> 2.37.0 (Apple Git-136) >>