This is DWARF specific, we don't have in CTF, AFAIK, info about where a
variable is put, i.e. in a register? in the stack? etc.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
We'll use location in the DWARF sense, i.e. location lists, etc, i.e.
where is this variable? In a register? The stack? etc.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Take 'struct task_struct' in the Linux kernel, these fields:
/* --- cacheline 2 boundary (128 bytes) --- */
struct sched_entity se; /* 128 448 */
/* XXX last struct has 24 bytes of padding */
/* --- cacheline 9 boundary (576 bytes) --- */
struct sched_rt_entity rt; /* 576 48 */
The sched_entity struct has 24 bytes of padding, and that info would
only appear when printing 'struct task_struct' if class__find_holes()
had previously been run on 'struct sched_entity' which wasn't always the
case, make sure that happens.
This results in this extra stat being printed for 'struct task_struct':
/* paddings: 4, sum paddings: 38 */
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
A diff for 'pahole -EC task_struct vmlinux' should clarify what this fixes:
[acme@jouet linux]$ diff -u /tmp/before.c /tmp/after.c | head -30
--- /tmp/before.c 2016-06-29 17:00:38.082647281 -0300
+++ /tmp/a.c 2016-06-29 17:03:36.913124779 -0300
@@ -43,8 +43,8 @@
struct list_head * prev; /* 176 8 */
} group_node; /* 168 16 */
unsigned int on_rq; /* 184 4 */
+ /* --- cacheline 3 boundary (192 bytes) --- */
/* typedef u64 */ long long unsigned int exec_start; /* 192 8 */
- /* --- cacheline 1 boundary (64 bytes) was 4 bytes ago --- */
/* typedef u64 */ long long unsigned int sum_exec_runtime; /* 200 8 */
/* typedef u64 */ long long unsigned int vruntime; /* 208 8 */
/* typedef u64 */ long long unsigned int prev_sum_exec_runtime; /* 216 8 */
@@ -53,40 +53,40 @@
/* typedef u64 */ long long unsigned int wait_start; /* 232 8 */
/* typedef u64 */ long long unsigned int wait_max; /* 240 8 */
/* typedef u64 */ long long unsigned int wait_count; /* 248 8 */
+ /* --- cacheline 4 boundary (256 bytes) --- */
/* typedef u64 */ long long unsigned int wait_sum; /* 256 8 */
/* typedef u64 */ long long unsigned int iowait_count; /* 264 8 */
/* typedef u64 */ long long unsigned int iowait_sum; /* 272 8 */
/* typedef u64 */ long long unsigned int sleep_start; /* 280 8 */
/* typedef u64 */ long long unsigned int sleep_max; /* 288 8 */
- /* --- cacheline 1 boundary (64 bytes) --- */
/* typedef s64 */ long long int sum_sleep_runtime; /* 296 8 */
/* typedef u64 */ long long unsigned int block_start; /* 304 8 */
/* typedef u64 */ long long unsigned int block_max; /* 312 8 */
+ /* --- cacheline 5 boundary (320 bytes) --- */
/* typedef u64 */ long long unsigned int exec_max; /* 320 8 */
/* typedef u64 */ long long unsigned int slice_max; /* 328 8 */
/* typedef u64 */ long long unsigned int nr_migrations_cold; /* 336 8 */
[acme@jouet linux]$
I.e. the boundary detection was being reset at each expanded struct, do the math globally,
using the member offset, that was already done globally and correctly.
Reported-and-Tested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
That conf_fprintf can be elided as it is always NULL for the root call,
i.e. only when expanding types is that it will be called recursively.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Still need to check what to fprintf for this, but at least have it in
the type lists so that we can find it.
Reported-by: Christophe Fergeau <cfergeau@redhat.com>
Cc: Dodji Seketeli <dodji@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Need to read more on http://www.artima.com/cppsource/rvalue.html, but
handling it mostly like DW_TAG_typedef so that at least references to it
are resolved, we can get its byte size, etc.
FIXME: look at the vtable parameters, some are resolving to "(null)".
Reported-by: Benjamin Kosnik <bkoz@redhat.com>
Reported-by: Mark Wieelard <mjw@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=962571
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
As Thomas Gleixner wisely pointed out, using 'self' is stoopid, it
doesn't convey useful information, so use sensible names
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
.debug_types is a new DWARF 4 feature that adds some simple
compression to DWARF. The basic idea is that identical type
definitions are merged by the linker and put into a new .debug_types
section.
This introduces 'dwarf_off_ref', which is like Dwarf_Off, but carries
a flag indicating if the DIE came from .debug_types. This allows
future uses to find the DIE properly.
Type units are read a little differently from ordinary CUs. All type
units are read at once, then types are recoded for them. (I think
something like this is needed more generally, to support inter-CU
references, but I have not tried that.)
The type unit is also kept around longer, because any other CU may
refer to it. This necessitated a change to load_steal_kind to replace
the notion of a "stolen" CU with a request by the "stealer" for the
caller to delete the CU when appropriate.
I need elfutils patch 581c3f60e2b1fc7ddaf4260bb5a9cb59f8e3f0d0
to make this work properly; without it I see crashes.
You can make test cases by compiling with '-gdwarf-4 -fdebug-types-section'.
So make it a :4 u8 to combine with the previous bitfield. This field is
also seldom used so no expected perf hit.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Since we have two bytes after it in a hole, use them for vtable_entry,
hell knows if there isn't any crazy code with that many vtable
entries...
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
As we had 14 bits hole, so use them as bools, each taking one byte
but generating better/shorter code.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
[acme@doppio pahole]$ pahole -F ctf /media/tb/debuginfo/usr/lib/debug/usr/bin/greycstoration4integration.debug > /tmp/bla
<ERROR(tag__size:837): detected type loop: type=572, tag=const_type>
<ERROR(tag__size:837): detected type loop: type=572, tag=const_type>
[acme@doppio pahole]$
These type loops are problems in the CTF encoding, that should be fixed, but
should not cause the core code to segfault on an infinite recursion.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
That asks dwarf_fprintf to always use "struct" in places where it would
use "class", because CTF doesn't have the "class" concept, so for
'regtest diffctf' sake, we use this.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
That can happen, for instance, when the symtabs are NOBITS. When that
happened we ended up in an infinite loop. Call it earlier and check the
result.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
In the same fashion as DW_TAG_volatile_type, as we need to get to the
DW_TAG_base_type at the end of the chain.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
If it is C++ add DW_TAG_member entries to cu->tags_table and at
imported_declaration__fprintf fallback to cu__tag() if cu__function()
fails.
The right thing tho, long term, is to have a class for
"DW_TAG_imported_declaration" to register to what kind of tag this
points, if for DW_TAG_subprogram or to DW_TAG_member, the info is in the
DWARF DW_AT_import attribute, but so far we're not decoding it.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
It doesn't matter when using a traditional malloc/free allocator, but
with obstacks we need to do it in reverse order.
For the usual case where we successfully process an object this doesn't
matter, as when we started using obstacks we don't traverse all the tags
calling their destructors anymore, we just free the whole obstack in one
go.
Noticed when processing object files built from non-supported languages
such as FORTRAN and Pascal, where there are some DWARF tags that are not
supported, which makes the object file load to be prematurely aborted
and that calls destructors for things like classes and functions that in
turn free space for their parameter/member lists, which now have to be
done in reverse order.
We could just stop calling the destructors and then destroying the whole
obstack, but I think that partially processed files are a nice feature,
so keep the interface in a way that both obstacks and traditinal malloc
alocators can be used.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Adding an enum so that CTF doesn't have to include dwarf.h and
setting the language to LANG_C in the CTF loader.
Next csets will handle C++ in a different way, because we may need
to find class sizes in a different CU since ancestors sometimes
are only forward declared...
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Next we'll add a new kind of tag, DW_TAG_perf_counter, that will come
from perf.data generated by 'perf report'.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
That is used by cus__find_function_by_addr & cu__func_function_by_addr.
First user is pfunct --addr, but this is really for pfunct --annotate, that
will process a perf.data file generated by 'perf report', load the debugging
info and regenerate the functions (pfunct -TVi like) that had hits, using
libdisasm to show the assembly code, etc.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Sharing the same space with abstract_origin, so that we can remove the last
Dwarf_Off in dwarf_fprintf.c.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
There is still the problem of handing the strings table to the CTF encoder, but
that will be fixed another day.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
So that we can use the strings in ".strtab" directly, without duplicating them
on the global strings table.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Instead pass thru cu__strings(cu, i) so that we can figure out if the
underlying debugging format handler can do that more efficiently, such as by
looking up directly the ELF section ".strtab".
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Such as signed, etc. This is in preparation for using directly ctf_strings.
Instead of duplicating it in the global strings table.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
