Subject: Re: [PATCH 2/2] perf annotate: add powerpc support

From: Arnaldo Carvalho de Melo <[email-masked]>
Date: Fri, 10 Jun 2016 10:36:44 -0300

Em Fri, Jun 10, 2016 at 06:32:51PM +0530, Naveen N. Rao escreveu:
> Convert ins__find() to a __weak function for generic functionality,
> while adding a powerpc-specific variant. We look at the function name
> for branch instructions and classify the instructions to one among a
> branch, a function call (branch with LR update) or a function return
> (branch to LR).

How would this allow one to get a perf.data collected on a powerpc
system, transfer it to a x86-64 (or aarch64, to mention another
workstation wannabe chip) system and then try annotating it?

There was a previous discussion about this, and it involved having all
yout ppc tables available as well as other arches tables, and then
choosing which one to use based on:

	normalize_arch(thread->mg->machine->env->arch)

just like was done for support cross unwinding, see recent patch kit by
He Kuang, CCed.

- Arnaldo
 
> Cc: Arnaldo Carvalho de Melo <[email-masked]>
> Cc: Anton Blanchard <[email-masked]>
> Cc: Michael Ellerman <[email-masked]>
> Cc: Ananth N Mavinakayanahalli <[email-masked]>
> Reported-by: Anton Blanchard <[email-masked]>
> Signed-off-by: Naveen N. Rao <[email-masked]>
> ---
>  tools/perf/arch/powerpc/util/Build      |  1 +
>  tools/perf/arch/powerpc/util/annotate.c | 58 +++++++++++++++++++++++++++++++++
>  tools/perf/util/annotate.c              | 17 +++++-----
>  tools/perf/util/annotate.h              |  9 +++++
>  4 files changed, 76 insertions(+), 9 deletions(-)
>  create mode 100644 tools/perf/arch/powerpc/util/annotate.c
> 
> diff --git a/tools/perf/arch/powerpc/util/Build b/tools/perf/arch/powerpc/util/Build
> index 90ad64b..d9e91d6 100644
> --- a/tools/perf/arch/powerpc/util/Build
> +++ b/tools/perf/arch/powerpc/util/Build
> @@ -2,6 +2,7 @@ libperf-y += header.o
>  libperf-y += sym-handling.o
>  libperf-y += kvm-stat.o
>  libperf-y += perf_regs.o
> +libperf-y += annotate.o
>  
>  libperf-$(CONFIG_DWARF) += dwarf-regs.o
>  libperf-$(CONFIG_DWARF) += skip-callchain-idx.o
> diff --git a/tools/perf/arch/powerpc/util/annotate.c b/tools/perf/arch/powerpc/util/annotate.c
> new file mode 100644
> index 0000000..f069bd7
> --- /dev/null
> +++ b/tools/perf/arch/powerpc/util/annotate.c
> @@ -0,0 +1,58 @@
> +#include "perf.h"
> +#include "annotate.h"
> +
> +struct ins *ins__find(const char *name)
> +{
> +	int i;
> +	struct ins *ins;
> +
> +	ins = zalloc(sizeof(struct ins));
> +	if (!ins)
> +		return NULL;
> +
> +	ins->name = strdup(name);
> +	if (!ins->name)
> +		return NULL;
> +
> +	if (name[0] == 'b') {
> +		/* branch instructions */
> +		ins->ops = &jump_ops;
> +
> +		/* these start with 'b', but aren't branch instructions */
> +		if (!strncmp(name, "bcd", 3) ||
> +				!strncmp(name, "brinc", 5) ||
> +				!strncmp(name, "bper", 4))
> +			return NULL;
> +
> +		i = strlen(name) - 1;
> +		if (i < 0)
> +			return NULL;
> +
> +		/* ignore optional hints at the end of the instructions */
> +		if (name[i] == '+' || name[i] == '-')
> +			i--;
> +
> +		if (name[i] == 'l' || (name[i] == 'a' && name[i-1] == 'l')) {
> +			/*
> +			 * if the instruction ends up with 'l' or 'la', then
> +			 * those are considered 'calls' since they update LR.
> +			 * ... except for 'bnl' which is branch if not less than
> +			 * and the absolute form of the same.
> +			 */
> +			if (strcmp(name, "bnl") && strcmp(name, "bnl+") &&
> +			    strcmp(name, "bnl-") && strcmp(name, "bnla") &&
> +			    strcmp(name, "bnla+") && strcmp(name, "bnla-"))
> +				ins->ops = &call_ops;
> +		}
> +		if (name[i] == 'r' && name[i-1] == 'l')
> +			/*
> +			 * instructions ending with 'lr' are considered to be
> +			 * return instructions
> +			 */
> +			ins->ops = &ret_ops;
> +
> +		return ins;
> +	}
> +
> +	return NULL;
> +}
> diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
> index e871b4e..0fa4fc5 100644
> --- a/tools/perf/util/annotate.c
> +++ b/tools/perf/util/annotate.c
> @@ -25,7 +25,6 @@ const char 	*disassembler_style;
>  const char	*objdump_path;
>  static regex_t	 file_lineno;
>  
> -static struct ins *ins__find(const char *name);
>  static int disasm_line__parse(char *line, char **namep, char **rawp);
>  
>  static void ins__delete(struct ins_operands *ops)
> @@ -107,7 +106,7 @@ static int call__scnprintf(struct ins *ins, char *bf, size_t size,
>  	return scnprintf(bf, size, "%-6.6s *%" PRIx64, ins->name, ops->target.addr);
>  }
>  
> -static struct ins_ops call_ops = {
> +struct ins_ops call_ops = {
>  	.parse	   = call__parse,
>  	.scnprintf = call__scnprintf,
>  };
> @@ -137,7 +136,7 @@ static int jump__scnprintf(struct ins *ins, char *bf, size_t size,
>  	return scnprintf(bf, size, "%-6.6s %" PRIx64, ins->name, ops->target.offset);
>  }
>  
> -static struct ins_ops jump_ops = {
> +struct ins_ops jump_ops = {
>  	.parse	   = jump__parse,
>  	.scnprintf = jump__scnprintf,
>  };
> @@ -230,7 +229,7 @@ static void lock__delete(struct ins_operands *ops)
>  	zfree(&ops->target.name);
>  }
>  
> -static struct ins_ops lock_ops = {
> +struct ins_ops lock_ops = {
>  	.free	   = lock__delete,
>  	.parse	   = lock__parse,
>  	.scnprintf = lock__scnprintf,
> @@ -298,7 +297,7 @@ static int mov__scnprintf(struct ins *ins, char *bf, size_t size,
>  			 ops->target.name ?: ops->target.raw);
>  }
>  
> -static struct ins_ops mov_ops = {
> +struct ins_ops mov_ops = {
>  	.parse	   = mov__parse,
>  	.scnprintf = mov__scnprintf,
>  };
> @@ -339,7 +338,7 @@ static int dec__scnprintf(struct ins *ins, char *bf, size_t size,
>  			 ops->target.name ?: ops->target.raw);
>  }
>  
> -static struct ins_ops dec_ops = {
> +struct ins_ops dec_ops = {
>  	.parse	   = dec__parse,
>  	.scnprintf = dec__scnprintf,
>  };
> @@ -350,11 +349,11 @@ static int nop__scnprintf(struct ins *ins __maybe_unused, char *bf, size_t size,
>  	return scnprintf(bf, size, "%-6.6s", "nop");
>  }
>  
> -static struct ins_ops nop_ops = {
> +struct ins_ops nop_ops = {
>  	.scnprintf = nop__scnprintf,
>  };
>  
> -static struct ins_ops ret_ops = {
> +struct ins_ops ret_ops = {
>  	.scnprintf = ins__raw_scnprintf,
>  };
>  
> @@ -478,7 +477,7 @@ static void ins__sort(void)
>  	qsort(instructions, nmemb, sizeof(struct ins), ins__cmp);
>  }
>  
> -static struct ins *ins__find(const char *name)
> +__weak struct ins *ins__find(const char *name)
>  {
>  	const int nmemb = ARRAY_SIZE(instructions);
>  	static bool sorted;
> diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
> index 720a4c0..6d89c1d 100644
> --- a/tools/perf/util/annotate.h
> +++ b/tools/perf/util/annotate.h
> @@ -50,6 +50,15 @@ bool ins__is_jump(const struct ins *ins);
>  bool ins__is_call(const struct ins *ins);
>  bool ins__is_ret(const struct ins *ins);
>  int ins__scnprintf(struct ins *ins, char *bf, size_t size, struct ins_operands *ops);
> +struct ins *ins__find(const char *name);
> +
> +extern struct ins_ops call_ops;
> +extern struct ins_ops jump_ops;
> +extern struct ins_ops ret_ops;
> +extern struct ins_ops mov_ops;
> +extern struct ins_ops lock_ops;
> +extern struct ins_ops dec_ops;
> +extern struct ins_ops nop_ops;
>  
>  struct annotation;
>  
> -- 
> 2.8.2