[PATCH] perf tools: add compatibility with libelf 0.8 and autodetect

[PATCH] perf tools: add compatibility with libelf 0.8 and autodetect

[Marti Raudsepp]

The Makefile now automatically defines LIBELF_NO_MMAP when libelf 0.8 is
detected. libelf 0.8 is still maintained and some distributions such as
Arch Linux use it instead of elfutils.

Signed-off-by: Marti Raudsepp <marti@juffo.org>
---
 tools/perf/Makefile      |    6 +++++-
 tools/perf/util/symbol.c |   12 ++++++++++++
 2 files changed, 17 insertions(+), 1 deletions(-)

diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index 742a32e..46e877b 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -422,7 +422,11 @@ ifeq ($(uname_S),Darwin)
 	PTHREAD_LIBS =
 endif
 
-ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
+ifeq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
+	ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
+		BASIC_CFLAGS += -DLIBELF_NO_MMAP
+	endif
+else
 	msg := $(error No libelf.h/libelf found, please install libelf-dev/elfutils-libelf-devel and glibc-dev[el]);
 endif
 
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 47ea060..8d1df1e 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -413,7 +413,11 @@ static int dso__synthesize_plt_symbols(struct  dso *self, int v)
 	if (fd < 0)
 		goto out;
 
+#ifdef LIBELF_NO_MMAP
+	elf = elf_begin(fd, ELF_C_READ, NULL);
+#else
 	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+#endif
 	if (elf == NULL)
 		goto out_close;
 
@@ -533,7 +537,11 @@ static int dso__load_sym(struct dso *self, int fd, const char *name,
 	Elf *elf;
 	int nr = 0, kernel = !strcmp("[kernel]", self->name);
 
+#ifdef LIBELF_NO_MMAP
+	elf = elf_begin(fd, ELF_C_READ, NULL);
+#else
 	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+#endif
 	if (elf == NULL) {
 		if (v)
 			fprintf(stderr, "%s: cannot read %s ELF file.\n",
@@ -675,7 +683,11 @@ static char *dso__read_build_id(struct dso *self, int v)
 	if (fd < 0)
 		goto out;
 
+#ifdef LIBELF_NO_MMAP
+	elf = elf_begin(fd, ELF_C_READ, NULL);
+#else
 	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+#endif
 	if (elf == NULL) {
 		if (v)
 			fprintf(stderr, "%s: cannot read %s ELF file.\n",
-- 
1.6.5.1

Re: [PATCH] perf tools: add compatibility with libelf 0.8 and autodetect

[Ingo Molnar]

* Marti Raudsepp <marti@juffo.org> wrote:

> The Makefile now automatically defines LIBELF_NO_MMAP when libelf 0.8 is
> detected. libelf 0.8 is still maintained and some distributions such as
> Arch Linux use it instead of elfutils.
> 
> Signed-off-by: Marti Raudsepp <marti@juffo.org>
> ---
>  tools/perf/Makefile      |    6 +++++-
>  tools/perf/util/symbol.c |   12 ++++++++++++
>  2 files changed, 17 insertions(+), 1 deletions(-)

Nice fix!

Mind doing a small change:

> diff --git a/tools/perf/Makefile b/tools/perf/Makefile
> index 742a32e..46e877b 100644
> --- a/tools/perf/Makefile
> +++ b/tools/perf/Makefile
> @@ -422,7 +422,11 @@ ifeq ($(uname_S),Darwin)
>  	PTHREAD_LIBS =
>  endif
>  
> -ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
> +ifeq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
> +	ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
> +		BASIC_CFLAGS += -DLIBELF_NO_MMAP
> +	endif
> +else
>  	msg := $(error No libelf.h/libelf found, please install libelf-dev/elfutils-libelf-devel and glibc-dev[el]);
>  endif
>  
> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
> index 47ea060..8d1df1e 100644
> --- a/tools/perf/util/symbol.c
> +++ b/tools/perf/util/symbol.c
> @@ -413,7 +413,11 @@ static int dso__synthesize_plt_symbols(struct  dso *self, int v)
>  	if (fd < 0)
>  		goto out;
>  
> +#ifdef LIBELF_NO_MMAP
> +	elf = elf_begin(fd, ELF_C_READ, NULL);
> +#else
>  	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
> +#endif
>  	if (elf == NULL)
>  		goto out_close;
>  
> @@ -533,7 +537,11 @@ static int dso__load_sym(struct dso *self, int fd, const char *name,
>  	Elf *elf;
>  	int nr = 0, kernel = !strcmp("[kernel]", self->name);
>  
> +#ifdef LIBELF_NO_MMAP
> +	elf = elf_begin(fd, ELF_C_READ, NULL);
> +#else
>  	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
> +#endif
>  	if (elf == NULL) {
>  		if (v)
>  			fprintf(stderr, "%s: cannot read %s ELF file.\n",
> @@ -675,7 +683,11 @@ static char *dso__read_build_id(struct dso *self, int v)
>  	if (fd < 0)
>  		goto out;
>  
> +#ifdef LIBELF_NO_MMAP
> +	elf = elf_begin(fd, ELF_C_READ, NULL);
> +#else
>  	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
> +#endif
>  	if (elf == NULL) {
>  		if (v)
>  			fprintf(stderr, "%s: cannot read %s ELF file.\n",

I think we want a small cleanup here: a perf_elf_begin() wrapper in a 
header file to hide this #ifdef. (That's how Git wraps environmental 
libraries as well.)

Also, this would be an urgent fix for v2.6.32 too, to make perf build on 
Arch Linux, agreed?

	Ingo

Re: [PATCH] perf tools: add compatibility with libelf 0.8 and autodetect

[Marti Raudsepp]

On Sat, Oct 24, 2009 at 12:02 AM, Ingo Molnar <mingo@elte.hu> wrote:
> Mind doing a small change:
>
> I think we want a small cleanup here: a perf_elf_begin() wrapper in a
> header file to hide this #ifdef. (That's how Git wraps environmental
> libraries as well.)

Ok, does this patch do what you had in mind? I wasn't quite sure how to
implement; changing the cmd behind someone's back might be considered
surprising.

Another take would be to #define our own ELF_C_READ_MMAP, but that would be
lying, too...

> Also, this would be an urgent fix for v2.6.32 too, to make perf build on
> Arch Linux, agreed?

Hopefully :)

Regards,
Marti


[PATCH] perf tools: add compatibility with libelf 0.8 and autodetect

The Makefile now automatically defines LIBELF_NO_MMAP when libelf 0.8 is
detected. libelf 0.8 is still maintained and some distributions such as
Arch Linux use it instead of elfutils.

Signed-off-by: Marti Raudsepp <marti@juffo.org>
---
 tools/perf/Makefile      |    6 +++++-
 tools/perf/util/symbol.c |    9 +++++----
 tools/perf/util/symbol.h |   11 +++++++++++
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index 742a32e..46e877b 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -422,7 +422,11 @@ ifeq ($(uname_S),Darwin)
 	PTHREAD_LIBS =
 endif
 
-ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
+ifeq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
+	ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
+		BASIC_CFLAGS += -DLIBELF_NO_MMAP
+	endif
+else
 	msg := $(error No libelf.h/libelf found, please install libelf-dev/elfutils-libelf-devel and glibc-dev[el]);
 endif
 
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 47ea060..ec69c42 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -5,7 +5,6 @@
 
 #include "debug.h"
 
-#include <libelf.h>
 #include <gelf.h>
 #include <elf.h>
 
@@ -413,7 +412,8 @@ static int dso__synthesize_plt_symbols(struct  dso *self, int v)
 	if (fd < 0)
 		goto out;
 
-	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+	elf = perf_elf_begin(fd, ELF_C_READ, NULL);
+
 	if (elf == NULL)
 		goto out_close;
 
@@ -533,7 +533,8 @@ static int dso__load_sym(struct dso *self, int fd, const char *name,
 	Elf *elf;
 	int nr = 0, kernel = !strcmp("[kernel]", self->name);
 
-	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+	elf = perf_elf_begin(fd, ELF_C_READ, NULL);
+
 	if (elf == NULL) {
 		if (v)
 			fprintf(stderr, "%s: cannot read %s ELF file.\n",
@@ -675,7 +676,7 @@ static char *dso__read_build_id(struct dso *self, int v)
 	if (fd < 0)
 		goto out;
 
-	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+	elf = perf_elf_begin(fd, ELF_C_READ, NULL);
 	if (elf == NULL) {
 		if (v)
 			fprintf(stderr, "%s: cannot read %s ELF file.\n",
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index 6e84907..50750e9 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -8,6 +8,8 @@
 #include "module.h"
 #include "event.h"
 
+#include <libelf.h>
+
 #ifdef HAVE_CPLUS_DEMANGLE
 extern char *cplus_demangle(const char *, int);
 
@@ -27,6 +29,15 @@ static inline char *bfd_demangle(void __used *v, const char __used *c,
 #endif
 #endif
 
+static inline Elf *perf_elf_begin(int fd, Elf_Cmd cmd, Elf *ref)
+{
+#ifndef LIBELF_NO_MMAP
+        if (cmd == ELF_C_READ)
+          cmd = ELF_C_READ_MMAP;
+#endif
+        return elf_begin(fd, cmd, ref);
+}
+
 #ifndef DMGL_PARAMS
 #define DMGL_PARAMS      (1 << 0)       /* Include function args */
 #define DMGL_ANSI        (1 << 1)       /* Include const, volatile, etc */
-- 
1.6.5.1

Re: [PATCH] perf tools: add compatibility with libelf 0.8 and autodetect

[Ingo Molnar]

* Marti Raudsepp <marti@juffo.org> wrote:

> On Sat, Oct 24, 2009 at 12:02 AM, Ingo Molnar <mingo@elte.hu> wrote:
> > Mind doing a small change:
> >
> > I think we want a small cleanup here: a perf_elf_begin() wrapper in a
> > header file to hide this #ifdef. (That's how Git wraps environmental
> > libraries as well.)
> 
> Ok, does this patch do what you had in mind? I wasn't quite sure how to
> implement; changing the cmd behind someone's back might be considered
> surprising.
> 
> Another take would be to #define our own ELF_C_READ_MMAP, but that would be
> lying, too...
> 
> > Also, this would be an urgent fix for v2.6.32 too, to make perf build on
> > Arch Linux, agreed?
> 
> Hopefully :)
> 
> Regards,
> Marti
> 
> 
> [PATCH] perf tools: add compatibility with libelf 0.8 and autodetect
> 
> The Makefile now automatically defines LIBELF_NO_MMAP when libelf 0.8 is
> detected. libelf 0.8 is still maintained and some distributions such as
> Arch Linux use it instead of elfutils.
> 
> Signed-off-by: Marti Raudsepp <marti@juffo.org>
> ---
>  tools/perf/Makefile      |    6 +++++-
>  tools/perf/util/symbol.c |    9 +++++----
>  tools/perf/util/symbol.h |   11 +++++++++++
>  3 files changed, 21 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/perf/Makefile b/tools/perf/Makefile
> index 742a32e..46e877b 100644
> --- a/tools/perf/Makefile
> +++ b/tools/perf/Makefile
> @@ -422,7 +422,11 @@ ifeq ($(uname_S),Darwin)
>  	PTHREAD_LIBS =
>  endif
>  
> -ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
> +ifeq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
> +	ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
> +		BASIC_CFLAGS += -DLIBELF_NO_MMAP
> +	endif
> +else
>  	msg := $(error No libelf.h/libelf found, please install libelf-dev/elfutils-libelf-devel and glibc-dev[el]);
>  endif
>  
> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
> index 47ea060..ec69c42 100644
> --- a/tools/perf/util/symbol.c
> +++ b/tools/perf/util/symbol.c
> @@ -5,7 +5,6 @@
>  
>  #include "debug.h"
>  
> -#include <libelf.h>
>  #include <gelf.h>
>  #include <elf.h>
>  
> @@ -413,7 +412,8 @@ static int dso__synthesize_plt_symbols(struct  dso *self, int v)
>  	if (fd < 0)
>  		goto out;
>  
> -	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
> +	elf = perf_elf_begin(fd, ELF_C_READ, NULL);
> +
>  	if (elf == NULL)
>  		goto out_close;
>  
> @@ -533,7 +533,8 @@ static int dso__load_sym(struct dso *self, int fd, const char *name,
>  	Elf *elf;
>  	int nr = 0, kernel = !strcmp("[kernel]", self->name);
>  
> -	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
> +	elf = perf_elf_begin(fd, ELF_C_READ, NULL);
> +
>  	if (elf == NULL) {
>  		if (v)
>  			fprintf(stderr, "%s: cannot read %s ELF file.\n",
> @@ -675,7 +676,7 @@ static char *dso__read_build_id(struct dso *self, int v)
>  	if (fd < 0)
>  		goto out;
>  
> -	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
> +	elf = perf_elf_begin(fd, ELF_C_READ, NULL);
>  	if (elf == NULL) {
>  		if (v)
>  			fprintf(stderr, "%s: cannot read %s ELF file.\n",
> diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
> index 6e84907..50750e9 100644
> --- a/tools/perf/util/symbol.h
> +++ b/tools/perf/util/symbol.h
> @@ -8,6 +8,8 @@
>  #include "module.h"
>  #include "event.h"
>  
> +#include <libelf.h>
> +
>  #ifdef HAVE_CPLUS_DEMANGLE
>  extern char *cplus_demangle(const char *, int);
>  
> @@ -27,6 +29,15 @@ static inline char *bfd_demangle(void __used *v, const char __used *c,
>  #endif
>  #endif
>  
> +static inline Elf *perf_elf_begin(int fd, Elf_Cmd cmd, Elf *ref)
> +{
> +#ifndef LIBELF_NO_MMAP
> +        if (cmd == ELF_C_READ)
> +          cmd = ELF_C_READ_MMAP;
> +#endif
> +        return elf_begin(fd, cmd, ref);
> +}
> +
>  #ifndef DMGL_PARAMS
>  #define DMGL_PARAMS      (1 << 0)       /* Include function args */
>  #define DMGL_ANSI        (1 << 1)       /* Include const, volatile, etc */

Looks nice!

Mind adding a comment as well to document the version dependency?

Also, there's a few probably unintended whitespaces in the patch not 
matching surrounding style (which is the kernel coding style) - please 
run the patch through scripts/checkpatch.pl.

	Ingo

Re: [PATCH] perf tools: add compatibility with libelf 0.8 and autodetect

[Lucas De Marchi]

(sorry, Ingo, forgot to reply-all)

On Fri, Oct 23, 2009 at 19:02, Ingo Molnar <mingo@elte.hu> wrote:
> Also, this would be an urgent fix for v2.6.32 too, to make perf build on
> Arch Linux, agreed?
>
If the fix is as simple as this patch, and will not cause any other
problems, may it be sent to -stable as well?


To make perf build on Arch is also possible to install elfutils from
AUR (http://aur.archlinux.org/packages.php?ID=5300) and I've made a
request some months ago to switch to this library instead of using
libelf but got no answers.

I think it's Arch's fault to continue using an unmaintained library
when there's an easy replacement, but if the "fix" is easy, why not?



Lucas De Marchi

Re: [PATCH] perf tools: add compatibility with libelf 0.8 and autodetect

[Marti Raudsepp]

On Sat, Oct 24, 2009 at 12:56 AM, Lucas De Marchi
<lucas.de.marchi@gmail.com> wrote:
> I think it's Arch's fault to continue using an unmaintained library
> when there's an easy replacement, but if the "fix" is easy, why not?

As far as I can tell, libelf is still maintained; the latest release
is from July 2009.

Regards,
Marti

Re: [PATCH] perf tools: add compatibility with libelf 0.8 and autodetect

[Marti Raudsepp]

On Sat, Oct 24, 2009 at 12:52 AM, Ingo Molnar <mingo@elte.hu> wrote:
> Mind adding a comment as well to document the version dependency?

Sure

> Also, there's a few probably unintended whitespaces

Fixed

--
perf tools: add compatibility with libelf 0.8 and autodetect

The Makefile now automatically defines LIBELF_NO_MMAP when libelf 0.8 is
detected. libelf 0.8 is still maintained and some distributions such as
Arch Linux use it instead of elfutils.

Signed-off-by: Marti Raudsepp <marti@juffo.org>
---
 tools/perf/Makefile      |    6 +++++-
 tools/perf/util/symbol.c |    9 +++++----
 tools/perf/util/symbol.h |   16 ++++++++++++++++
 3 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index 742a32e..46e877b 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -422,7 +422,11 @@ ifeq ($(uname_S),Darwin)
 	PTHREAD_LIBS =
 endif
 
-ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
+ifeq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
+	ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
+		BASIC_CFLAGS += -DLIBELF_NO_MMAP
+	endif
+else
 	msg := $(error No libelf.h/libelf found, please install libelf-dev/elfutils-libelf-devel and glibc-dev[el]);
 endif
 
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 47ea060..ec69c42 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -5,7 +5,6 @@
 
 #include "debug.h"
 
-#include <libelf.h>
 #include <gelf.h>
 #include <elf.h>
 
@@ -413,7 +412,8 @@ static int dso__synthesize_plt_symbols(struct  dso *self, int v)
 	if (fd < 0)
 		goto out;
 
-	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+	elf = perf_elf_begin(fd, ELF_C_READ, NULL);
+
 	if (elf == NULL)
 		goto out_close;
 
@@ -533,7 +533,8 @@ static int dso__load_sym(struct dso *self, int fd, const char *name,
 	Elf *elf;
 	int nr = 0, kernel = !strcmp("[kernel]", self->name);
 
-	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+	elf = perf_elf_begin(fd, ELF_C_READ, NULL);
+
 	if (elf == NULL) {
 		if (v)
 			fprintf(stderr, "%s: cannot read %s ELF file.\n",
@@ -675,7 +676,7 @@ static char *dso__read_build_id(struct dso *self, int v)
 	if (fd < 0)
 		goto out;
 
-	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+	elf = perf_elf_begin(fd, ELF_C_READ, NULL);
 	if (elf == NULL) {
 		if (v)
 			fprintf(stderr, "%s: cannot read %s ELF file.\n",
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index 6e84907..38bc832 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -8,6 +8,8 @@
 #include "module.h"
 #include "event.h"
 
+#include <libelf.h>
+
 #ifdef HAVE_CPLUS_DEMANGLE
 extern char *cplus_demangle(const char *, int);
 
@@ -27,6 +29,20 @@ static inline char *bfd_demangle(void __used *v, const char __used *c,
 #endif
 #endif
 
+static inline Elf *perf_elf_begin(int fd, Elf_Cmd cmd, Elf *ref)
+{
+#ifndef LIBELF_NO_MMAP
+	/*
+	 * libelf 0.8 and earlier do not support ELF_C_READ_MMAP; for newer
+	 * versions we can use mmap to reduce memory usage
+	 */
+
+	if (cmd == ELF_C_READ)
+		cmd = ELF_C_READ_MMAP;
+#endif
+	return elf_begin(fd, cmd, ref);
+}
+
 #ifndef DMGL_PARAMS
 #define DMGL_PARAMS      (1 << 0)       /* Include function args */
 #define DMGL_ANSI        (1 << 1)       /* Include const, volatile, etc */
-- 
1.6.5.1

Re: [PATCH] perf tools: add compatibility with libelf 0.8 and autodetect

[Lucas De Marchi]

On Fri, Oct 23, 2009 at 19:59, Marti Raudsepp <marti@juffo.org> wrote:
> On Sat, Oct 24, 2009 at 12:56 AM, Lucas De Marchi
> <lucas.de.marchi@gmail.com> wrote:
>> I think it's Arch's fault to continue using an unmaintained library
>> when there's an easy replacement, but if the "fix" is easy, why not?
>
> As far as I can tell, libelf is still maintained; the latest release
> is from July 2009.
>

humn... I was looking at FSF site
(http://directory.fsf.org/project/libelf/) where version was not
updated anymore.


Lucas De Marchi

Re: [PATCH] perf tools: add compatibility with libelf 0.8 and autodetect

[Lucas De Marchi]

On Fri, Oct 23, 2009 at 19:48, Marti Raudsepp <marti@juffo.org> wrote:
> On Sat, Oct 24, 2009 at 12:02 AM, Ingo Molnar <mingo@elte.hu> wrote:
>> Mind doing a small change:
>>
>> I think we want a small cleanup here: a perf_elf_begin() wrapper in a
>> header file to hide this #ifdef. (That's how Git wraps environmental
>> libraries as well.)
>
Why don't you do something like?:

#ifdef LIBELF_NO_MMAP
#define ELF_C_READ_MMAP ELF_C_READ
#endif
+ changes to Makefile

or:

#ifndef ELF_C_READ_MMAP
#define ELF_C_READ_MMAP ELF_C_READ
#endif

Re: [PATCH] perf tools: add compatibility with libelf 0.8 and autodetect

[Marti Raudsepp]

On Sat, Oct 24, 2009 at 4:07 AM, Lucas De Marchi
<lucas.de.marchi@gmail.com> wrote:
> Why don't you do something like?:
>
> #ifdef LIBELF_NO_MMAP
> #define ELF_C_READ_MMAP ELF_C_READ
> #endif

Seemed like bad programming practice to redefine enum constants from
third-party include files. But you are right, it would significantly
simplify the patch. Can we get a third opinion?

Marti

Re: [PATCH] perf tools: add compatibility with libelf 0.8 and autodetect

[Ingo Molnar]

* Lucas De Marchi <lucas.de.marchi@gmail.com> wrote:

> On Fri, Oct 23, 2009 at 19:48, Marti Raudsepp <marti@juffo.org> wrote:
> > On Sat, Oct 24, 2009 at 12:02 AM, Ingo Molnar <mingo@elte.hu> wrote:
> >> Mind doing a small change:
> >>
> >> I think we want a small cleanup here: a perf_elf_begin() wrapper in a
> >> header file to hide this #ifdef. (That's how Git wraps environmental
> >> libraries as well.)
> >
> Why don't you do something like?:
> 
> #ifdef LIBELF_NO_MMAP
> #define ELF_C_READ_MMAP ELF_C_READ
> #endif
> + changes to Makefile
> 
> or:
> 
> #ifndef ELF_C_READ_MMAP
> #define ELF_C_READ_MMAP ELF_C_READ
> #endif

Makes sense - i'd suggest to prefix it with PERF_ in that case, to make 
sure all callsites are aware of the wrapped nature of this constant. 

I.e. something like this:

/*
 * libelf 0.8 and earlier do not support ELF_C_READ_MMAP;
 * for newer versions we can use mmap to reduce memory usage:
 */
#ifndef ELF_C_READ_MMAP
# define PERF_ELF_C_READ_MMAP ELF_C_READ
#endif

	Ingo

Re: [PATCH] perf tools: add compatibility with libelf 0.8 and autodetect

[Lucas De Marchi]

On Sat, Oct 24, 2009 at 06:30, Ingo Molnar <mingo@elte.hu> wrote:
> I.e. something like this:
>
> /*
>  * libelf 0.8 and earlier do not support ELF_C_READ_MMAP;
>  * for newer versions we can use mmap to reduce memory usage:
>  */
> #ifndef ELF_C_READ_MMAP
> # define PERF_ELF_C_READ_MMAP ELF_C_READ
> #endif

In this case you should define PERF_ELF_C_READ_MMAP as ELF_C_READ_MMAP
when using elftutils:
#ifndef ELF_C_READ_MMAP
# define PERF_ELF_C_READ_MMAP ELF_C_READ
#else
# define PERF_ELF_C_READ_MMAP ELF_C_READ_MMAP
#endif

and change all places to use PERF_ELF_C_READ_MMAP


I think the comment is wrong. I downloaded the latest version of
libelf, i.e. 0.8.12 at http://www.mr511.de/software/english.html, and
there's no support to ELF_C_READ_MMAP. It's a elfutils' feature only.

Re: [PATCH] perf tools: add compatibility with libelf 0.8 and autodetect

[Marti Raudsepp]

On Sat, 2009-10-24 at 11:26 -0200, Lucas De Marchi wrote:
> In this case you should define PERF_ELF_C_READ_MMAP as ELF_C_READ_MMAP
> when using elftutils:
> #ifndef ELF_C_READ_MMAP
> # define PERF_ELF_C_READ_MMAP ELF_C_READ
> #else
> # define PERF_ELF_C_READ_MMAP ELF_C_READ_MMAP
> #endif

That's what I wanted to do at first, but it doesn't work because
ELF_C_READ_MMAP is an enum constant -- not a #define

But defining our own PERF_ELF_C_READ_MMAP is a good idea and much
cleaner than the earlier mess. Thanks

> I think the comment is wrong. I downloaded the latest version of
> libelf, i.e. 0.8.12 at http://www.mr511.de/software/english.html, and
> there's no support to ELF_C_READ_MMAP. It's a elfutils' feature only.

I guess the comment was confusing. With "libelf 0.8" I meant the whole
0.8.x series.

Marti

--

perf tools: add compatibility with libelf 0.8.x and autodetect

The Makefile now automatically defines LIBELF_NO_MMAP when libelf 0.8.x is
detected. libelf 0.8.x is still maintained and some distributions such as
Arch Linux use it instead of elfutils.

Can't use #ifdef ELF_C_READ_MMAP because it's an enum constant not a
define.

Signed-off-by: Marti Raudsepp <marti@juffo.org>
---
 Makefile      |    6 +++++-
 util/symbol.c |    6 +++---
 util/symbol.h |   10 ++++++++++
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/tools/perf/Makefile b/tools/perf/Makefile
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -422,7 +422,11 @@
 	PTHREAD_LIBS =
 endif
 
-ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
+ifeq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
+	ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
+		BASIC_CFLAGS += -DLIBELF_NO_MMAP
+	endif
+else
 	msg := $(error No libelf.h/libelf found, please install libelf-dev/elfutils-libelf-devel and glibc-dev[el]);
 endif
 
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -413,7 +413,7 @@
 	if (fd < 0)
 		goto out;
 
-	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 	if (elf == NULL)
 		goto out_close;
 
@@ -533,7 +533,7 @@
 	Elf *elf;
 	int nr = 0, kernel = !strcmp("[kernel]", self->name);
 
-	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 	if (elf == NULL) {
 		if (v)
 			fprintf(stderr, "%s: cannot read %s ELF file.\n",
@@ -675,7 +675,7 @@
 	if (fd < 0)
 		goto out;
 
-	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 	if (elf == NULL) {
 		if (v)
 			fprintf(stderr, "%s: cannot read %s ELF file.\n",
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -27,6 +27,16 @@
 #endif
 #endif
 
+/*
+ * libelf 0.8.x and earlier do not support elf_c_read_mmap; for newer versions
+ * we can use mmap to reduce memory usage
+ */
+#ifdef LIBELF_NO_MMAP
+# define PERF_ELF_C_READ_MMAP ELF_C_READ
+#else
+# define PERF_ELF_C_READ_MMAP ELF_C_READ_MMAP
+#endif
+
 #ifndef DMGL_PARAMS
 #define DMGL_PARAMS      (1 << 0)       /* Include function args */
 #define DMGL_ANSI        (1 << 1)       /* Include const, volatile, etc */

Re: [PATCH] perf tools: add compatibility with libelf 0.8 and autodetect

[Marti Raudsepp]

Re-sending small fix; somehow I typed "elf_c_read_mmap" in lower case in
the comment.

Marti

--

perf tools: add compatibility with libelf 0.8.x and autodetect

The Makefile now automatically defines LIBELF_NO_MMAP when libelf 0.8.x is
detected. libelf 0.8.x is still maintained and some distributions such as
Arch Linux use it instead of elfutils.

Can't use #ifdef ELF_C_READ_MMAP because it's an enum constant not a
define.

Signed-off-by: Marti Raudsepp <marti@juffo.org>
---
 Makefile      |    6 +++++-
 util/symbol.c |    6 +++---
 util/symbol.h |   10 ++++++++++
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/tools/perf/Makefile b/tools/perf/Makefile
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -422,7 +422,11 @@
        PTHREAD_LIBS =
 endif
 
-ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
+ifeq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
+       ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
+               BASIC_CFLAGS += -DLIBELF_NO_MMAP
+       endif
+else
        msg := $(error No libelf.h/libelf found, please install libelf-dev/elfutils-libelf-devel and glibc-dev[el]);
 endif
 
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -413,7 +413,7 @@
        if (fd < 0)
                goto out;
 
-       elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+       elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
        if (elf == NULL)
                goto out_close;
 
@@ -533,7 +533,7 @@
        Elf *elf;
        int nr = 0, kernel = !strcmp("[kernel]", self->name);
 
-       elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+       elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
        if (elf == NULL) {
                if (v)
                        fprintf(stderr, "%s: cannot read %s ELF file.\n",
@@ -675,7 +675,7 @@
        if (fd < 0)
                goto out;
 
-       elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+       elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
        if (elf == NULL) {
                if (v)
                        fprintf(stderr, "%s: cannot read %s ELF file.\n",
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -27,6 +27,16 @@
 #endif
 #endif
 
+/*
+ * libelf 0.8.x and earlier do not support ELF_C_READ_MMAP; for newer versions
+ * we can use mmap to reduce memory usage
+ */
+#ifdef LIBELF_NO_MMAP
+# define PERF_ELF_C_READ_MMAP ELF_C_READ
+#else
+# define PERF_ELF_C_READ_MMAP ELF_C_READ_MMAP
+#endif
+
 #ifndef DMGL_PARAMS
 #define DMGL_PARAMS      (1 << 0)       /* Include function args */
 #define DMGL_ANSI        (1 << 1)       /* Include const, volatile, etc */

Re: [PATCH] perf tools: add compatibility with libelf 0.8 and autodetect

[Ingo Molnar]

* Marti Raudsepp <marti@juffo.org> wrote:

> Re-sending small fix; somehow I typed "elf_c_read_mmap" in lower case 
> in the comment.

The patch got whitespace damaged (tabs are spaces, etc.) - please see 
Documentation/email-clients.txt.
 
	Ingo

Re: [PATCH] perf tools: add compatibility with libelf 0.8 and autodetect

[Marti Raudsepp]

On Sat, 2009-10-24 at 17:41 +0200, Ingo Molnar wrote:
> The patch got whitespace damaged (tabs are spaces, etc.) - please see 
> Documentation/email-clients.txt.

Jeez, I spent most of my morning testing how to use different email
clients and I still can't get it right. :/

Marti

---
perf tools: add compatibility with libelf 0.8.x and autodetect

The Makefile now automatically defines LIBELF_NO_MMAP when libelf 0.8.x is
detected. libelf 0.8 is still maintained and some distributions such as
Arch Linux use it instead of elfutils.

Signed-off-by: Marti Raudsepp <marti@juffo.org>

diff --git a/tools/perf/Makefile b/tools/perf/Makefile
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -422,7 +422,11 @@
 	PTHREAD_LIBS =
 endif
 
-ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
+ifeq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
+	ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)
+		BASIC_CFLAGS += -DLIBELF_NO_MMAP
+	endif
+else
 	msg := $(error No libelf.h/libelf found, please install libelf-dev/elfutils-libelf-devel and glibc-dev[el]);
 endif
 
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -413,7 +413,7 @@
 	if (fd < 0)
 		goto out;
 
-	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 	if (elf == NULL)
 		goto out_close;
 
@@ -533,7 +533,7 @@
 	Elf *elf;
 	int nr = 0, kernel = !strcmp("[kernel]", self->name);
 
-	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 	if (elf == NULL) {
 		if (v)
 			fprintf(stderr, "%s: cannot read %s ELF file.\n",
@@ -675,7 +675,7 @@
 	if (fd < 0)
 		goto out;
 
-	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 	if (elf == NULL) {
 		if (v)
 			fprintf(stderr, "%s: cannot read %s ELF file.\n",
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -27,6 +27,16 @@
 #endif
 #endif
 
+/*
+ * libelf 0.8.x and earlier do not support ELF_C_READ_MMAP; for newer versions
+ * we can use mmap to reduce memory usage
+ */
+#ifdef LIBELF_NO_MMAP
+# define PERF_ELF_C_READ_MMAP ELF_C_READ
+#else
+# define PERF_ELF_C_READ_MMAP ELF_C_READ_MMAP
+#endif
+
 #ifndef DMGL_PARAMS
 #define DMGL_PARAMS      (1 << 0)       /* Include function args */
 #define DMGL_ANSI        (1 << 1)       /* Include const, volatile, etc */