linux-kernel - Re: [PATCH 02/48] perf annotate: Check if operand has multiple regs

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Date:   Mon, 27 Nov 2023 16:05:58 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Namhyung Kim <namhyung@...nel.org>
Cc:     Jiri Olsa <jolsa@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ian Rogers <irogers@...gle.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Ingo Molnar <mingo@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-perf-users@...r.kernel.org,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Stephane Eranian <eranian@...gle.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        linux-toolchains@...r.kernel.org, linux-trace-devel@...r.kernel.org
Subject: Re: [PATCH 02/48] perf annotate: Check if operand has multiple regs

Em Wed, Oct 11, 2023 at 08:50:25PM -0700, Namhyung Kim escreveu:
> It needs to check all possible information in an instruction.  Let's add
> a field indicating if the operand has multiple registers.  I'll be used
> to search type information like in an array access on x86 like:
> 
>   mov    0x10(%rax,%rbx,8), %rcx
>              -------------
>                  here

Cherry picked this patch.

- Arnaldo
 
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> ---
>  tools/perf/util/annotate.c | 36 ++++++++++++++++++++++++++++++++++++
>  tools/perf/util/annotate.h |  2 ++
>  2 files changed, 38 insertions(+)
> 
> diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
> index 211636e65b03..605298410ed4 100644
> --- a/tools/perf/util/annotate.c
> +++ b/tools/perf/util/annotate.c
> @@ -85,6 +85,8 @@ struct arch {
>  	struct		{
>  		char comment_char;
>  		char skip_functions_char;
> +		char register_char;
> +		char memory_ref_char;
>  	} objdump;
>  };
>  
> @@ -188,6 +190,8 @@ static struct arch architectures[] = {
>  		.insn_suffix = "bwlq",
>  		.objdump =  {
>  			.comment_char = '#',
> +			.register_char = '%',
> +			.memory_ref_char = '(',
>  		},
>  	},
>  	{
> @@ -566,6 +570,34 @@ static struct ins_ops lock_ops = {
>  	.scnprintf = lock__scnprintf,
>  };
>  
> +/*
> + * Check if the operand has more than one registers like x86 SIB addressing:
> + *   0x1234(%rax, %rbx, 8)
> + *
> + * But it doesn't care segment selectors like %gs:0x5678(%rcx), so just check
> + * the input string after 'memory_ref_char' if exists.
> + */
> +static bool check_multi_regs(struct arch *arch, const char *op)
> +{
> +	int count = 0;
> +
> +	if (arch->objdump.register_char == 0)
> +		return false;
> +
> +	if (arch->objdump.memory_ref_char) {
> +		op = strchr(op, arch->objdump.memory_ref_char);
> +		if (op == NULL)
> +			return false;
> +	}
> +
> +	while ((op = strchr(op, arch->objdump.register_char)) != NULL) {
> +		count++;
> +		op++;
> +	}
> +
> +	return count > 1;
> +}
> +
>  static int mov__parse(struct arch *arch, struct ins_operands *ops, struct map_symbol *ms __maybe_unused)
>  {
>  	char *s = strchr(ops->raw, ','), *target, *comment, prev;
> @@ -593,6 +625,8 @@ static int mov__parse(struct arch *arch, struct ins_operands *ops, struct map_sy
>  	if (ops->source.raw == NULL)
>  		return -1;
>  
> +	ops->source.multi_regs = check_multi_regs(arch, ops->source.raw);
> +
>  	target = skip_spaces(++s);
>  	comment = strchr(s, arch->objdump.comment_char);
>  
> @@ -613,6 +647,8 @@ static int mov__parse(struct arch *arch, struct ins_operands *ops, struct map_sy
>  	if (ops->target.raw == NULL)
>  		goto out_free_source;
>  
> +	ops->target.multi_regs = check_multi_regs(arch, ops->target.raw);
> +
>  	if (comment == NULL)
>  		return 0;
>  
> diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
> index 9d8b4199e3bd..e33a55431bad 100644
> --- a/tools/perf/util/annotate.h
> +++ b/tools/perf/util/annotate.h
> @@ -39,12 +39,14 @@ struct ins_operands {
>  		s64	offset;
>  		bool	offset_avail;
>  		bool	outside;
> +		bool	multi_regs;
>  	} target;
>  	union {
>  		struct {
>  			char	*raw;
>  			char	*name;
>  			u64	addr;
> +			bool	multi_regs;
>  		} source;
>  		struct {
>  			struct ins	    ins;
> -- 
> 2.42.0.655.g421f12c284-goog
> 

-- 

- Arnaldo