LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Nick Gasson <nick.gasson@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] perf jvmti: Fix demangling Java symbols
Date: Wed, 27 May 2020 11:10:28 -0300
Message-ID: <20200527141028.GE14219@kernel.org> (raw)
In-Reply-To: <20200427061520.24905-4-nick.gasson@arm.com>

Em Mon, Apr 27, 2020 at 02:15:16PM +0800, Nick Gasson escreveu:
> For a Java method signature like:
> 
>     Ljava/lang/AbstractStringBuilder;appendChars(Ljava/lang/String;II)V
> 
> The demangler produces:
> 
>     void class java.lang.AbstractStringBuilder.appendChars(class java.lang., shorttring., int, int)

Cool, one more 'perf test' entry, thanks a lot!

Applied,

- Arnaldo
 
> The arguments should be (java.lang.String, int, int) but the demangler
> interprets the "S" in String as the type code for "short". Correct this
> and two other minor things:
> 
> - There is no "bool" type in Java, should be "boolean".
> 
> - The demangler prepends "class" to every Java class name. This is not
>   standard Java syntax and it wastes a lot of horizontal space if the
>   signature is long. Remove this as there isn't any ambiguity between
>   class names and primitives.
> 
> Also added a test case.
> 
> Signed-off-by: Nick Gasson <nick.gasson@arm.com>
> ---
>  tools/perf/tests/Build                |  1 +
>  tools/perf/tests/builtin-test.c       |  4 +++
>  tools/perf/tests/demangle-java-test.c | 42 +++++++++++++++++++++++++++
>  tools/perf/tests/tests.h              |  1 +
>  tools/perf/util/demangle-java.c       | 13 +++++----
>  5 files changed, 55 insertions(+), 6 deletions(-)
>  create mode 100644 tools/perf/tests/demangle-java-test.c
> 
> diff --git a/tools/perf/tests/Build b/tools/perf/tests/Build
> index 1692529639b0..2c45ac4a9581 100644
> --- a/tools/perf/tests/Build
> +++ b/tools/perf/tests/Build
> @@ -55,6 +55,7 @@ perf-y += mem2node.o
>  perf-y += maps.o
>  perf-y += time-utils-test.o
>  perf-y += genelf.o
> +perf-y += demangle-java-test.o
>  
>  $(OUTPUT)tests/llvm-src-base.c: tests/bpf-script-example.c tests/Build
>  	$(call rule_mkdir)
> diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
> index 54d9516c9839..03b362b37f97 100644
> --- a/tools/perf/tests/builtin-test.c
> +++ b/tools/perf/tests/builtin-test.c
> @@ -309,6 +309,10 @@ static struct test generic_tests[] = {
>  		.desc = "maps__merge_in",
>  		.func = test__maps__merge_in,
>  	},
> +	{
> +		.desc = "Demangle Java",
> +		.func = test__demangle_java,
> +	},
>  	{
>  		.func = NULL,
>  	},
> diff --git a/tools/perf/tests/demangle-java-test.c b/tools/perf/tests/demangle-java-test.c
> new file mode 100644
> index 000000000000..8f3b90832fb0
> --- /dev/null
> +++ b/tools/perf/tests/demangle-java-test.c
> @@ -0,0 +1,42 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <string.h>
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include "tests.h"
> +#include "session.h"
> +#include "debug.h"
> +#include "demangle-java.h"
> +
> +int test__demangle_java(struct test *test __maybe_unused, int subtest __maybe_unused)
> +{
> +	int ret = TEST_OK;
> +	char *buf = NULL;
> +	size_t i;
> +
> +	struct {
> +		const char *mangled, *demangled;
> +	} test_cases[] = {
> +		{ "Ljava/lang/StringLatin1;equals([B[B)Z",
> +		  "boolean java.lang.StringLatin1.equals(byte[], byte[])" },
> +		{ "Ljava/util/zip/ZipUtils;CENSIZ([BI)J",
> +		  "long java.util.zip.ZipUtils.CENSIZ(byte[], int)" },
> +		{ "Ljava/util/regex/Pattern$BmpCharProperty;match(Ljava/util/regex/Matcher;ILjava/lang/CharSequence;)Z",
> +		  "boolean java.util.regex.Pattern$BmpCharProperty.match(java.util.regex.Matcher, int, java.lang.CharSequence)" },
> +		{ "Ljava/lang/AbstractStringBuilder;appendChars(Ljava/lang/String;II)V",
> +		  "void java.lang.AbstractStringBuilder.appendChars(java.lang.String, int, int)" },
> +		{ "Ljava/lang/Object;<init>()V",
> +		  "void java.lang.Object<init>()" },
> +	};
> +
> +	for (i = 0; i < sizeof(test_cases) / sizeof(test_cases[0]); i++) {
> +		buf = java_demangle_sym(test_cases[i].mangled, 0);
> +		if (strcmp(buf, test_cases[i].demangled)) {
> +			pr_debug("FAILED: %s: %s != %s\n", test_cases[i].mangled,
> +				 buf, test_cases[i].demangled);
> +			ret = TEST_FAIL;
> +		}
> +		free(buf);
> +	}
> +
> +	return ret;
> +}
> diff --git a/tools/perf/tests/tests.h b/tools/perf/tests/tests.h
> index 9a160fef47c9..49b791d978f6 100644
> --- a/tools/perf/tests/tests.h
> +++ b/tools/perf/tests/tests.h
> @@ -111,6 +111,7 @@ int test__mem2node(struct test *t, int subtest);
>  int test__maps__merge_in(struct test *t, int subtest);
>  int test__time_utils(struct test *t, int subtest);
>  int test__jit_write_elf(struct test *test, int subtest);
> +int test__demangle_java(struct test *test, int subtest);
>  
>  bool test__bp_signal_is_supported(void);
>  bool test__bp_account_is_supported(void);
> diff --git a/tools/perf/util/demangle-java.c b/tools/perf/util/demangle-java.c
> index 6fb7f34c0814..39c05200ed65 100644
> --- a/tools/perf/util/demangle-java.c
> +++ b/tools/perf/util/demangle-java.c
> @@ -15,7 +15,7 @@ enum {
>  	MODE_CLASS  = 1,
>  	MODE_FUNC   = 2,
>  	MODE_TYPE   = 3,
> -	MODE_CTYPE  = 3, /* class arg */
> +	MODE_CTYPE  = 4, /* class arg */
>  };
>  
>  #define BASE_ENT(c, n)	[c - 'A']=n
> @@ -27,7 +27,7 @@ static const char *base_types['Z' - 'A' + 1] = {
>  	BASE_ENT('I', "int" ),
>  	BASE_ENT('J', "long" ),
>  	BASE_ENT('S', "short" ),
> -	BASE_ENT('Z', "bool" ),
> +	BASE_ENT('Z', "boolean" ),
>  };
>  
>  /*
> @@ -59,15 +59,16 @@ __demangle_java_sym(const char *str, const char *end, char *buf, int maxlen, int
>  
>  		switch (*q) {
>  		case 'L':
> -			if (mode == MODE_PREFIX || mode == MODE_CTYPE) {
> -				if (mode == MODE_CTYPE) {
> +			if (mode == MODE_PREFIX || mode == MODE_TYPE) {
> +				if (mode == MODE_TYPE) {
>  					if (narg)
>  						rlen += scnprintf(buf + rlen, maxlen - rlen, ", ");
>  					narg++;
>  				}
> -				rlen += scnprintf(buf + rlen, maxlen - rlen, "class ");
>  				if (mode == MODE_PREFIX)
>  					mode = MODE_CLASS;
> +				else
> +					mode = MODE_CTYPE;
>  			} else
>  				buf[rlen++] = *q;
>  			break;
> @@ -120,7 +121,7 @@ __demangle_java_sym(const char *str, const char *end, char *buf, int maxlen, int
>  			if (mode != MODE_CLASS && mode != MODE_CTYPE)
>  				goto error;
>  			/* safe because at least one other char to process */
> -			if (isalpha(*(q + 1)))
> +			if (isalpha(*(q + 1)) && mode == MODE_CLASS)
>  				rlen += scnprintf(buf + rlen, maxlen - rlen, ".");
>  			if (mode == MODE_CLASS)
>  				mode = MODE_FUNC;
> -- 
> 2.26.1
> 

-- 

- Arnaldo

  parent reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-27  6:15 [PATCH 0/3] perf jvmti: Various fixes to JVMTI agent Nick Gasson
2020-04-27  6:15 ` [PATCH 1/3] perf jvmti: Fix jitdump for methods without debug info Nick Gasson
2020-05-14 22:06   ` Ian Rogers
2020-04-27  6:15 ` [PATCH 2/3] perf jvmti: Do not report error when missing debug information Nick Gasson
2020-05-14 22:08   ` Ian Rogers
2020-05-27 14:07   ` Arnaldo Carvalho de Melo
2020-05-27 14:08     ` Arnaldo Carvalho de Melo
2020-04-27  6:15 ` [PATCH 3/3] perf jvmti: Fix demangling Java symbols Nick Gasson
2020-05-14 22:09   ` Ian Rogers
2020-05-27 14:10   ` Arnaldo Carvalho de Melo [this message]
2020-05-27 14:20   ` Arnaldo Carvalho de Melo
2020-05-27 16:23     ` Arnaldo Carvalho de Melo
2020-05-27 22:34       ` Arnaldo Carvalho de Melo
2020-05-28  5:42         ` Nick Gasson
2020-04-27 10:35 ` [PATCH 0/3] perf jvmti: Various fixes to JVMTI agent Jiri Olsa
2020-05-14  8:56   ` Nick Gasson
2020-05-14 13:23     ` Arnaldo Carvalho de Melo
2020-05-14 22:41       ` Ian Rogers
2020-05-15  7:45         ` Nick Gasson

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200527141028.GE14219@kernel.org \
    --to=acme@kernel.org \
    --cc=alexander.shishkin@linux.intel.com \
    --cc=jolsa@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mark.rutland@arm.com \
    --cc=mingo@redhat.com \
    --cc=namhyung@kernel.org \
    --cc=nick.gasson@arm.com \
    --cc=peterz@infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git