From patchwork Tue Mar 19 05:51:06 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Namhyung Kim X-Patchwork-Id: 13596143 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0BDEE7F7C1; Tue, 19 Mar 2024 05:51:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710827487; cv=none; b=mxZtdfEtubj7xlpITcuyOEfXpy+r/nsqBaB43Ikr8pjnCGN3Vcsq2XTytVwsx1zaOKq7j46Z4IfEDd7o7d06OBi/E9rsYAtl4b5Ca8z4oaMsdyzT8ZqYJzN0kEx3gUSB0veM9zg24c5jsYUv7Nj+VuN8ofe+Ta7tT69h2LryOpM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710827487; c=relaxed/simple; bh=61VgKV31vYUBRqV9qo2hI10KmXR//3S4gszy882fliQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ja81ylFSkFVeF/imS9gKkkV/YSNWz/xOGEHN8iYMz71ZCS0ZYhEyqVorwIXggrUGzS0yidn6d3ZE3MsLX2enID04DblGg82fA8DY0tGk7Irtr52XYkup+8vTk+fC/39gf0YOzDyAJTjIPwydaDrNaP2/cUUGCwnzi0JKuuQyn3o= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=umhuJVF1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="umhuJVF1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 93B82C43601; Tue, 19 Mar 2024 05:51:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1710827486; bh=61VgKV31vYUBRqV9qo2hI10KmXR//3S4gszy882fliQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=umhuJVF1TrukWwX4W8toYsh8simW7cVs5LfANlcSY4rJe8oE+iM71gf5/+ieAkRRU fI08EWBEqlqeGsnltQUpReQuGEhto9gGpo3Y00SKELgTtACcm1F9IWCm2MBwU2Q7gg Fcnc2YvmiBDp7pHCU5N1xIjC0fWjpp69VAksCUXOnjyYftcpAIMurb/AnTRHajHn1L xn2z1ygbE3XgbaPbH76HK1gVdqhg2ERRwQX2GINKyLqzglauVtElU8zNEhibzWNHMB WWA7vMXl+Xs8mWKUjFbRMXjHT/PLYpVw6PietBj7Fk47xPHRnHyGvysa6Ey6jekW9B HeyMZ7+HIhAbA== From: Namhyung Kim To: Arnaldo Carvalho de Melo , Ian Rogers Cc: Jiri Olsa , Adrian Hunter , Peter Zijlstra , Ingo Molnar , LKML , linux-perf-users@vger.kernel.org, Linus Torvalds , Stephane Eranian , Masami Hiramatsu , linux-toolchains@vger.kernel.org, linux-trace-devel@vger.kernel.org Subject: [PATCH 14/23] perf annotate-data: Implement instruction tracking Date: Mon, 18 Mar 2024 22:51:06 -0700 Message-ID: <20240319055115.4063940-15-namhyung@kernel.org> X-Mailer: git-send-email 2.44.0.291.gc1ea87d7ee-goog In-Reply-To: <20240319055115.4063940-1-namhyung@kernel.org> References: <20240319055115.4063940-1-namhyung@kernel.org> Precedence: bulk X-Mailing-List: linux-trace-devel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 If it failed to find a variable for the location directly, it might be due to a missing variable in the source code. For example, accessing pointer variables in a chain can result in the case like below: struct foo *foo = ...; int i = foo->bar->baz; The DWARF debug information is created for each variable so it'd have one for 'foo'. But there's no variable for 'foo->bar' and then it cannot know the type of 'bar' and 'baz'. The above source code can be compiled to the follow x86 instructions: mov 0x8(%rax), %rcx mov 0x4(%rcx), %rdx <=== PMU sample mov %rdx, -4(%rbp) Let's say 'foo' is located in the %rax and it has a pointer to struct foo. But perf sample is captured in the second instruction and there is no variable or type info for the %rcx. It'd be great if compiler could generate debug info for %rcx, but we should handle it on our side. So this patch implements the logic to iterate instructions and update the type table for each location. As it already collected a list of scopes including the target instruction, we can use it to construct the type table smartly. +---------------- scope[0] subprogram | | +-------------- scope[1] lexical_block | | | | +------------ scope[2] inlined_subroutine | | | | | | +---------- scope[3] inlined_subroutine | | | | | | | | +-------- scope[4] lexical_block | | | | | | | | | | *** target instruction ... Image the target instruction has 5 scopes, each scope will have its own variables and parameters. Then it can start with the innermost scope (4). So it'd search the shortest path from the start of scope[4] to the target address and build a list of basic blocks. Then it iterates the basic blocks with the variables in the scope and update the table. If it finds a type at the target instruction, then returns it. Otherwise, it moves to the upper scope[3]. Now it'd search the shortest path from the start of scope[3] to the start of scope[4]. Then connect it to the existing basic block list. Then it'd iterate the blocks with variables for both scopes. It can repeat this until it finds a type at the target instruction or reaches to the top scope[0]. As the basic blocks contain the shortest path, it won't worry about branches and can update the table simply. The final check will be done by find_matching_type() in the next patch. Signed-off-by: Namhyung Kim --- tools/perf/builtin-annotate.c | 1 + tools/perf/util/annotate-data.c | 223 ++++++++++++++++++++++++++++++-- tools/perf/util/annotate-data.h | 1 + 3 files changed, 211 insertions(+), 14 deletions(-) diff --git a/tools/perf/builtin-annotate.c b/tools/perf/builtin-annotate.c index 6c1cc797692d..f677671409b1 100644 --- a/tools/perf/builtin-annotate.c +++ b/tools/perf/builtin-annotate.c @@ -430,6 +430,7 @@ static void print_annotate_data_stat(struct annotated_data_stat *s) PRINT_STAT(no_typeinfo); PRINT_STAT(invalid_size); PRINT_STAT(bad_offset); + PRINT_STAT(insn_track); printf("\n"); #undef PRINT_STAT diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c index 6bcf22e523cb..13ba65693367 100644 --- a/tools/perf/util/annotate-data.c +++ b/tools/perf/util/annotate-data.c @@ -89,15 +89,7 @@ static bool has_reg_type(struct type_state *state, int reg) return (unsigned)reg < ARRAY_SIZE(state->regs); } -/* These declarations will be remove once they are changed to static */ -void init_type_state(struct type_state *state, struct arch *arch __maybe_unused); -void exit_type_state(struct type_state *state); -void update_var_state(struct type_state *state, struct data_loc_info *dloc, - u64 addr, u64 insn_offset, struct die_var_type *var_types); -void update_insn_state(struct type_state *state, struct data_loc_info *dloc, - Dwarf_Die *cu_die, struct disasm_line *dl); - -void init_type_state(struct type_state *state, struct arch *arch) +static void init_type_state(struct type_state *state, struct arch *arch) { memset(state, 0, sizeof(*state)); INIT_LIST_HEAD(&state->stack_vars); @@ -116,7 +108,7 @@ void init_type_state(struct type_state *state, struct arch *arch) } } -void exit_type_state(struct type_state *state) +static void exit_type_state(struct type_state *state) { struct type_state_stack *stack, *tmp; @@ -457,8 +449,8 @@ static bool get_global_var_type(Dwarf_Die *cu_die, struct data_loc_info *dloc, * This function fills the @state table using @var_types info. Each variable * is used only at the given location and updates an entry in the table. */ -void update_var_state(struct type_state *state, struct data_loc_info *dloc, - u64 addr, u64 insn_offset, struct die_var_type *var_types) +static void update_var_state(struct type_state *state, struct data_loc_info *dloc, + u64 addr, u64 insn_offset, struct die_var_type *var_types) { Dwarf_Die mem_die; struct die_var_type *var; @@ -716,13 +708,207 @@ static void update_insn_state_x86(struct type_state *state, * Note that ops->reg2 is only available when both mem_ref and multi_regs * are true. */ -void update_insn_state(struct type_state *state, struct data_loc_info *dloc, - Dwarf_Die *cu_die, struct disasm_line *dl) +static void update_insn_state(struct type_state *state, struct data_loc_info *dloc, + Dwarf_Die *cu_die, struct disasm_line *dl) { if (arch__is(dloc->arch, "x86")) update_insn_state_x86(state, dloc, cu_die, dl); } +/* + * Prepend this_blocks (from the outer scope) to full_blocks, removing + * duplicate disasm line. + */ +static void prepend_basic_blocks(struct list_head *this_blocks, + struct list_head *full_blocks) +{ + struct annotated_basic_block *first_bb, *last_bb; + + last_bb = list_last_entry(this_blocks, typeof(*last_bb), list); + first_bb = list_first_entry(full_blocks, typeof(*first_bb), list); + + if (list_empty(full_blocks)) + goto out; + + /* Last insn in this_blocks should be same as first insn in full_blocks */ + if (last_bb->end != first_bb->begin) { + pr_debug("prepend basic blocks: mismatched disasm line %"PRIx64" -> %"PRIx64"\n", + last_bb->end->al.offset, first_bb->begin->al.offset); + goto out; + } + + /* Is the basic block have only one disasm_line? */ + if (last_bb->begin == last_bb->end) { + list_del(&last_bb->list); + free(last_bb); + goto out; + } + + /* Point to the insn before the last when adding this block to full_blocks */ + last_bb->end = list_prev_entry(last_bb->end, al.node); + +out: + list_splice(this_blocks, full_blocks); +} + +static void delete_basic_blocks(struct list_head *basic_blocks) +{ + struct annotated_basic_block *bb, *tmp; + + list_for_each_entry_safe(bb, tmp, basic_blocks, list) { + list_del(&bb->list); + free(bb); + } +} + +/* Make sure all variables have a valid start address */ +static void fixup_var_address(struct die_var_type *var_types, u64 addr) +{ + while (var_types) { + /* + * Some variables have no address range meaning it's always + * available in the whole scope. Let's adjust the start + * address to the start of the scope. + */ + if (var_types->addr == 0) + var_types->addr = addr; + + var_types = var_types->next; + } +} + +static void delete_var_types(struct die_var_type *var_types) +{ + while (var_types) { + struct die_var_type *next = var_types->next; + + free(var_types); + var_types = next; + } +} + +/* It's at the target address, check if it has a matching type */ +static bool find_matching_type(struct type_state *state __maybe_unused, + struct data_loc_info *dloc __maybe_unused, + int reg __maybe_unused, + Dwarf_Die *type_die __maybe_unused) +{ + /* TODO */ + return false; +} + +/* Iterate instructions in basic blocks and update type table */ +static bool find_data_type_insn(struct data_loc_info *dloc, int reg, + struct list_head *basic_blocks, + struct die_var_type *var_types, + Dwarf_Die *cu_die, Dwarf_Die *type_die) +{ + struct type_state state; + struct symbol *sym = dloc->ms->sym; + struct annotation *notes = symbol__annotation(sym); + struct annotated_basic_block *bb; + bool found = false; + + init_type_state(&state, dloc->arch); + + list_for_each_entry(bb, basic_blocks, list) { + struct disasm_line *dl = bb->begin; + + pr_debug_dtp("bb: [%"PRIx64" - %"PRIx64"]\n", + bb->begin->al.offset, bb->end->al.offset); + + list_for_each_entry_from(dl, ¬es->src->source, al.node) { + u64 this_ip = sym->start + dl->al.offset; + u64 addr = map__rip_2objdump(dloc->ms->map, this_ip); + + /* Update variable type at this address */ + update_var_state(&state, dloc, addr, dl->al.offset, var_types); + + if (this_ip == dloc->ip) { + found = find_matching_type(&state, dloc, reg, + type_die); + goto out; + } + + /* Update type table after processing the instruction */ + update_insn_state(&state, dloc, cu_die, dl); + if (dl == bb->end) + break; + } + } + +out: + exit_type_state(&state); + return found; +} + +/* + * Construct a list of basic blocks for each scope with variables and try to find + * the data type by updating a type state table through instructions. + */ +static int find_data_type_block(struct data_loc_info *dloc, int reg, + Dwarf_Die *cu_die, Dwarf_Die *scopes, + int nr_scopes, Dwarf_Die *type_die) +{ + LIST_HEAD(basic_blocks); + struct die_var_type *var_types = NULL; + u64 src_ip, dst_ip, prev_dst_ip; + int ret = -1; + + /* TODO: other architecture support */ + if (!arch__is(dloc->arch, "x86")) + return -1; + + prev_dst_ip = dst_ip = dloc->ip; + for (int i = nr_scopes - 1; i >= 0; i--) { + Dwarf_Addr base, start, end; + LIST_HEAD(this_blocks); + + if (dwarf_ranges(&scopes[i], 0, &base, &start, &end) < 0) + break; + + pr_debug_dtp("scope: [%d/%d] (die:%lx)\n", + i + 1, nr_scopes, (long)dwarf_dieoffset(&scopes[i])); + src_ip = map__objdump_2rip(dloc->ms->map, start); + +again: + /* Get basic blocks for this scope */ + if (annotate_get_basic_blocks(dloc->ms->sym, src_ip, dst_ip, + &this_blocks) < 0) { + /* Try previous block if they are not connected */ + if (prev_dst_ip != dst_ip) { + dst_ip = prev_dst_ip; + goto again; + } + + pr_debug_dtp("cannot find a basic block from %"PRIx64" to %"PRIx64"\n", + src_ip - dloc->ms->sym->start, + dst_ip - dloc->ms->sym->start); + continue; + } + prepend_basic_blocks(&this_blocks, &basic_blocks); + + /* Get variable info for this scope and add to var_types list */ + die_collect_vars(&scopes[i], &var_types); + fixup_var_address(var_types, start); + + /* Find from start of this scope to the target instruction */ + if (find_data_type_insn(dloc, reg, &basic_blocks, var_types, + cu_die, type_die)) { + ret = 0; + break; + } + + /* Go up to the next scope and find blocks to the start */ + prev_dst_ip = dst_ip; + dst_ip = src_ip; + } + + delete_basic_blocks(&basic_blocks); + delete_var_types(var_types); + return ret; +} + /* The result will be saved in @type_die */ static int find_data_type_die(struct data_loc_info *dloc, Dwarf_Die *type_die) { @@ -847,6 +1033,15 @@ static int find_data_type_die(struct data_loc_info *dloc, Dwarf_Die *type_die) goto out; } + if (reg != DWARF_REG_PC) { + ret = find_data_type_block(dloc, reg, &cu_die, scopes, + nr_scopes, type_die); + if (ret == 0) { + ann_data_stat.insn_track++; + goto out; + } + } + if (loc->multi_regs && reg == loc->reg1 && loc->reg1 != loc->reg2) { reg = loc->reg2; goto retry; diff --git a/tools/perf/util/annotate-data.h b/tools/perf/util/annotate-data.h index acfbd1748d02..ae0f87aed804 100644 --- a/tools/perf/util/annotate-data.h +++ b/tools/perf/util/annotate-data.h @@ -135,6 +135,7 @@ struct annotated_data_stat { int no_typeinfo; int invalid_size; int bad_offset; + int insn_track; }; extern struct annotated_data_stat ann_data_stat;