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Date: Sat, 21 Feb 2015 12:17:05 +0900
From: Namhyung Kim <namhyung@...nel.org>
To: Stephane Eranian <eranian@...gle.com>
Cc: linux-kernel@...r.kernel.org, acme@...hat.com,
peterz@...radead.org, mingo@...e.hu, ak@...ux.intel.com,
jolsa@...hat.com, cel@...ibm.com, sukadev@...ux.vnet.ibm.com,
sonnyrao@...omium.org, johnmccutchan@...gle.com, dsahern@...il.com,
adrian.hunter@...el.com, pawel.moll@....com
Subject: Re: [PATCH v3 1/4] perf tools: add Java demangling support
Hi Stephane,
On Wed, Feb 18, 2015 at 10:40:25PM +0100, Stephane Eranian wrote:
> Add Java function descriptor demangling support.
> Something bfd cannot do.
>
> Use the JAVA_DEMANGLE_NORET flag to avoid decoding the
> return type of functions.
>
> Signed-off-by: Stephane Eranian <eranian@...gle.com>
> ---
> tools/perf/Makefile.perf | 2 +
> tools/perf/util/demangle-java.c | 199 ++++++++++++++++++++++++++++++++++++++++
> tools/perf/util/demangle-java.h | 10 ++
> tools/perf/util/symbol-elf.c | 3 +
> tools/perf/util/symbol.c | 6 +-
> 5 files changed, 219 insertions(+), 1 deletion(-)
> create mode 100644 tools/perf/util/demangle-java.c
> create mode 100644 tools/perf/util/demangle-java.h
>
> diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
> index aa6a504..53a44be 100644
> --- a/tools/perf/Makefile.perf
> +++ b/tools/perf/Makefile.perf
> @@ -331,6 +331,7 @@ LIB_H += ui/ui.h
> LIB_H += util/data.h
> LIB_H += util/kvm-stat.h
> LIB_H += util/thread-stack.h
> +LIB_H += util/demangle-java.h
>
> LIB_OBJS += $(OUTPUT)util/abspath.o
> LIB_OBJS += $(OUTPUT)util/alias.o
> @@ -410,6 +411,7 @@ LIB_OBJS += $(OUTPUT)util/data.o
> LIB_OBJS += $(OUTPUT)util/tsc.o
> LIB_OBJS += $(OUTPUT)util/cloexec.o
> LIB_OBJS += $(OUTPUT)util/thread-stack.o
> +LIB_OBJS += $(OUTPUT)util/demangle-java.o
>
> LIB_OBJS += $(OUTPUT)ui/setup.o
> LIB_OBJS += $(OUTPUT)ui/helpline.o
> diff --git a/tools/perf/util/demangle-java.c b/tools/perf/util/demangle-java.c
> new file mode 100644
> index 0000000..79d5484
> --- /dev/null
> +++ b/tools/perf/util/demangle-java.c
> @@ -0,0 +1,199 @@
> +#include <sys/types.h>
> +#include <stdio.h>
> +#include <string.h>
> +#include "util.h"
> +#include "debug.h"
> +#include "symbol.h"
> +
> +#include "demangle-java.h"
> +
> +enum {
> + MODE_PREFIX=0,
> + MODE_CLASS=1,
> + MODE_FUNC=2,
> + MODE_TYPE=3,
> + MODE_CTYPE=3, /* class arg */
> +};
> +
> +#define BASE_ENT(c, n) [c-'A']=n
> +static const char *base_types['Z'-'A' + 1]={
> + BASE_ENT('B', "byte" ),
> + BASE_ENT('C', "char" ),
> + BASE_ENT('D', "double" ),
> + BASE_ENT('F', "float" ),
> + BASE_ENT('I', "int" ),
> + BASE_ENT('J', "long" ),
> + BASE_ENT('S', "short" ),
> + BASE_ENT('Z', "bool" ),
> +};
> +
> +/*
> + * demangle Java symbol between str and end positions and stores
> + * up to maxlen characters into buf. The parser starts in mode.
> + *
> + * Use MODE_PREFIX to process entire prototype till end position
So this still includes the argument (type) right? I just worry about
that it might fill up the precious screen width of TUI like C++
symbols did before..
> + * Use MODE_TYPE to process return type if str starts on return type char
What about MODE_CTYPE? I cannot find where it's used..
> + *
> + * Return:
> + * success: buf
> + * error : NULL
> + */
> +static char *
> +__demangle_java_sym(const char *str, const char *end, char *buf, int maxlen, int mode)
> +{
> + int rlen = 0;
> + int array = 0;
> + int narg = 0;
> + const char *q;
> +
> + if (!end)
> + end = str + strlen(str);
> +
> + for (q = str; q != end; q++) {
> +
> + if (rlen == (maxlen - 1))
> + break;
> +
> + switch (*q) {
> + case 'L':
> + if (mode == MODE_PREFIX || mode == MODE_CTYPE) {
> + if (mode == MODE_CTYPE) {
> + if (narg)
> + rlen += snprintf(buf+rlen, maxlen - rlen, ", ");
> + narg++;
> + }
> + rlen += snprintf(buf+rlen, maxlen - rlen, "class ");
> + if (mode == MODE_PREFIX)
> + mode = MODE_CLASS;
> + } else
> + buf[rlen++] = *q;
> + break;
> + case 'B':
> + case 'C':
> + case 'D':
> + case 'F':
> + case 'I':
> + case 'J':
> + case 'S':
> + case 'Z':
> + if (mode == MODE_TYPE) {
> + if (narg)
> + rlen += snprintf(buf+rlen, maxlen - rlen, ", ");
> + rlen += snprintf(buf+rlen, maxlen - rlen, "%s", base_types[*q - 'A']);
> + while(array--)
> + rlen += snprintf(buf+rlen, maxlen - rlen, "[]");
> + array = 0;
> + narg++;
> + } else
> + buf[rlen++] = *q;
> + break;
> + case 'V':
> + if (mode == MODE_TYPE) {
> + rlen += snprintf(buf+rlen, maxlen - rlen, "void");
> + while(array--)
> + rlen += snprintf(buf+rlen, maxlen - rlen, "[]");
> + array = 0;
> + } else
> + buf[rlen++] = *q;
> + break;
> + case '[':
> + if (mode != MODE_TYPE)
> + goto error;
> + array++;
> + break;
> + case '(':
> + if (mode != MODE_FUNC)
> + goto error;
> + buf[rlen++] = *q;
> + mode = MODE_TYPE;
> + break;
> + case ')':
> + if (mode != MODE_TYPE)
> + goto error;
> + buf[rlen++] = *q;
> + narg = 0;
> + break;
> + case ';':
> + if (mode != MODE_CLASS && mode != MODE_CTYPE)
> + goto error;
> + /* safe because at least one other char to process */
> + if (isalpha(*(q+1)))
> + rlen += snprintf(buf+rlen, maxlen - rlen, ".");
> + if (mode == MODE_CLASS)
> + mode = MODE_FUNC;
> + else if (mode == MODE_CTYPE)
> + mode = MODE_TYPE;
> + break;
> + case '/':
> + if (mode != MODE_CLASS && mode != MODE_CTYPE)
> + goto error;
> + rlen += snprintf(buf+rlen, maxlen - rlen, ".");
> + break;
> + default :
> + buf[rlen++] = *q;
> + }
> + }
> + buf[rlen] = '\0';
> + return buf;
> +error:
> + return NULL;
> +}
> +
> +/*
> + * Demangle Java function signature (openJDK, not GCJ)
> + * input:
> + * str: string to parse. String is not modified
> + * flags: comobination of JAVA_DEMANGLE_* flags to modify demangling
> + * return:
> + * if input can be demangled, then a newly allocated string is returned.
> + * if input cannot be demangled, then NULL is returned
> + *
> + * Note: caller is responsible for freeing demangled string
> + */
> +char *
> +java_demangle_sym(const char *str, int flags)
> +{
> + char *buf, *ptr;
> + char *p;
> + size_t len, l1 = 0;
> +
> + if (!str)
> + return NULL;
> +
> + /* find start of retunr type */
> + p = strrchr(str, ')');
> + if (!p)
> + return NULL;
> +
> + /*
> + * expansion factor estimated to 3x
> + */
> + len = strlen(str) * 3 + 1;
> + buf = malloc(len);
> + if (!buf)
> + return NULL;
> +
> + buf[0] = '\0';
> + if (!(flags & JAVA_DEMANGLE_NORET)) {
> + /*
> + * get return type first
> + */
> + ptr = __demangle_java_sym(p+1, NULL, buf, len, MODE_TYPE);
> + if (!ptr)
> + goto error;
> +
> + /* add space between return type and function prototype */
> + l1 = strlen(buf);
> + buf[l1++] = ' ';
> + }
> +
> + /* process function up to return type */
> + ptr = __demangle_java_sym(str, p + 1, buf + l1, len - l1, MODE_PREFIX);
> + if (!ptr)
> + goto error;
> +
> + return buf;
> +error:
> + free(buf);
> + return NULL;
> +}
> diff --git a/tools/perf/util/demangle-java.h b/tools/perf/util/demangle-java.h
> new file mode 100644
> index 0000000..a981c1f
> --- /dev/null
> +++ b/tools/perf/util/demangle-java.h
> @@ -0,0 +1,10 @@
> +#ifndef __PERF_DEMANGLE_JAVA
> +#define __PERF_DEMANGLE_JAVA 1
> +/*
> + * demangle function flags
> + */
> +#define JAVA_DEMANGLE_NORET 0x1 /* do not process return type */
> +
> +char * java_demangle_sym(const char *str, int flags);
> +
> +#endif /* __PERF_DEMANGLE_JAVA */
> diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
> index b24f9d8..73b3e8f 100644
> --- a/tools/perf/util/symbol-elf.c
> +++ b/tools/perf/util/symbol-elf.c
> @@ -6,6 +6,7 @@
> #include <inttypes.h>
>
> #include "symbol.h"
> +#include "demangle-java.h"
> #include "machine.h"
> #include "vdso.h"
> #include <symbol/kallsyms.h>
> @@ -1019,6 +1020,8 @@ int dso__load_sym(struct dso *dso, struct map *map,
> demangle_flags = DMGL_PARAMS | DMGL_ANSI;
>
> demangled = bfd_demangle(NULL, elf_name, demangle_flags);
> + if (demangled == NULL)
> + demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
> if (demangled != NULL)
> elf_name = demangled;
> }
> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
> index a690668..3bc779b 100644
> --- a/tools/perf/util/symbol.c
> +++ b/tools/perf/util/symbol.c
> @@ -9,6 +9,7 @@
> #include <fcntl.h>
> #include <unistd.h>
> #include <inttypes.h>
> +#include <bfd.h>
Wouldn't it break build on systems don't have the bfd devel package?
And I don't see why it's needed here..
> #include "build-id.h"
> #include "util.h"
> #include "debug.h"
> @@ -1257,6 +1258,7 @@ static int dso__load_perf_map(struct dso *dso, struct map *map,
> u64 start, size;
> struct symbol *sym;
> int line_len, len;
> + char *name;
>
> line_len = getline(&line, &n, file);
> if (line_len < 0)
> @@ -1279,7 +1281,9 @@ static int dso__load_perf_map(struct dso *dso, struct map *map,
> if (len + 2 >= line_len)
> continue;
>
> - sym = symbol__new(start, size, STB_GLOBAL, line + len);
> + name = line + len;
> +
> + sym = symbol__new(start, size, STB_GLOBAL, name);
I think this file is not a part of this changeset.
Thanks,
Namhyung
>
> if (sym == NULL)
> goto out_delete_line;
> --
> 1.9.1
>
--
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