perf probe: Check if dwarf_getlocations() is available

If not, tell the user that:

  config/Makefile:273: Old libdw.h, finding variables at given 'perf probe' point will not work, install elfutils-devel/libdw-dev >= 0.157

And return -ENOTSUPP in die_get_var_range(), failing features that
need it, like the one pointed out above.

This fixes the build on older systems, such as Ubuntu 12.04.5.

Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Vinson Lee <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
This commit is contained in:
Arnaldo Carvalho de Melo 2016-04-05 11:33:41 -03:00
commit 4924734570
6 changed files with 38 additions and 0 deletions

View file

@ -268,6 +268,12 @@ else
ifneq ($(feature-dwarf), 1)
msg := $(warning No libdw.h found or old libdw.h found or elfutils is older than 0.138, disables dwarf support. Please install new elfutils-devel/libdw-dev);
NO_DWARF := 1
else
ifneq ($(feature-dwarf_getlocations), 1)
msg := $(warning Old libdw.h, finding variables at given 'perf probe' point will not work, install elfutils-devel/libdw-dev >= 0.157);
else
CFLAGS += -DHAVE_DWARF_GETLOCATIONS
endif # dwarf_getlocations
endif # Dwarf support
endif # libelf support
endif # NO_LIBELF

View file

@ -959,6 +959,7 @@ int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf)
return 0;
}
#ifdef HAVE_DWARF_GETLOCATIONS
/**
* die_get_var_innermost_scope - Get innermost scope range of given variable DIE
* @sp_die: a subprogram DIE
@ -1080,3 +1081,11 @@ int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf)
return ret;
}
#else
int die_get_var_range(Dwarf_Die *sp_die __maybe_unused,
Dwarf_Die *vr_die __maybe_unused,
struct strbuf *buf __maybe_unused)
{
return -ENOTSUP;
}
#endif