On 10/25/23 11:51, Cupertino Miranda wrote:
> Hi everyone,
>
> This patch contains some more recent improvements to BPF CO-RE builtins.
> Please find further details of the changes on the patch header.
>
> Looking forward for your review and comments.
>
> Best regards,
> Cupertino Miranda
Hi
On 10/26/23 08:08, Cupertino Miranda wrote:
>
> Changes from v1:
> - Fixed Davids remarks on initial patch.
> - Fixed mistake with deleted '*'.
>
> Changes from v2:
> - Reversed return value for bpf_const_not_ok_for_debug_p function.
Hmm..
> +static bool
> +bpf_const_not_ok_for_debug_p (r
Hi Cupertino,
On 10/30/23 12:39, Cupertino Miranda wrote:
>
> Hi everyone,
>
> Please find a new version for the review as inline attachment.
>
> Best regards,
> Cupertino
>
This version LGTM.
Thanks!
>
> Changes from v4:
> - Implemented TARGET_DELEGITIMIZE_ADDRESS target hook as the prope
On 10/31/23 09:58, David Faust wrote:
> Hi Cupertino,
>
> On 10/30/23 12:39, Cupertino Miranda wrote:
>>
>> Hi everyone,
>>
>> Please find a new version for the review as inline attachment.
>>
>> Best regards,
>> Cupertino
>>
The array member of struct SFOO in the ctf-file-scope-1 caused the test
to fail for the BPF target, since BPF does not support dynamic stack
allocation. The array does not need to variable length for the sake of
the test, so make it fixed length instead to allow the test to run
successfully for the
Similar to memmove and memcpy, the BPF backend cannot fall back on a
library call to implement __builtin_memset, and should always expand
calls to it inline if possible.
This patch implements simple inline expansion of memset in the BPF
backend in a verifier-friendly way. Similar to memcpy and mem
Hi Indu, Cupertino,
On 3/4/24 10:00, Indu Bhagat wrote:
> From: Cupertino Miranda
>
> [Changes from V1]
> - Refactor the code a bit.
> [End of changes from V1]
>
> PR debug/114186
>
> DWARF DIEs of type DW_TAG_subrange_type are linked together to represent
> the information about the subsequ
On 3/5/24 00:47, Indu Bhagat wrote:
> From: Cupertino Miranda
>
> [Changes from V2]
> - Fixed aarch64 new FAILs reported by Linaro CI.
> - Fixed typos and other nits pointed out in V2.
> [End of changes from V2]
OK, thanks.
>
> PR debug/114186
>
> DWARF DIEs of type DW_TAG_subrange_typ
BPF cannot fall back on library calls to implement memmove, memcpy and
memset, so we attempt to expand these inline always if possible.
However, this inline expansion was being attempted even for excessively
large operations, which could result in gcc consuming huge amounts of
memory and hanging.
The test was trying to do too much by both checking for an error, and
checking the resulting assembly. Of course, due to the error no asm was
produced, so the scan-asm went unresolved. Split it into two separate
tests to fix the issue.
Tested on x86_64-linux-gnu host for bpf-unknown-none target.
[Changes from v1:
- Error if threshold is exceeded instead of silently emitting libcall
- Update test accordingly
- Expand documentation to explain this behavior ]
BPF cannot fall back on library calls to implement memmove, memcpy and
memset, so we attempt to expand these inline always if poss
Change the BPF backend to define INT8_TYPE with an explicit sign, rather
than a plain char. This is in line with other targets and removes the
risk of int8_t being affected by the signedness of the plain char type
of the host system.
Tested on x86_64-linux-gnu host for bpf-unknown-none.
Sanity ch
On 3/14/24 10:16, Jose E. Marchesi wrote:
>
> Hi David.
>
>> Change the BPF backend to define INT8_TYPE with an explicit sign, rather
>> than a plain char. This is in line with other targets and removes the
>> risk of int8_t being affected by the signedness of the plain char type
>> of the ho
On 3/13/24 07:24, Cupertino Miranda wrote:
> Although part of all CO-RE relocation data, type based relocations do
> not require an access string.
> Initial implementation defined it as an empty string.
> On the other hand, libbpf when parsing the CO-RE relocations verifies
> that those strings
On 3/13/24 07:24, Cupertino Miranda wrote:
> Any unnamed structure field if not a member of the BTF_KIND_STRUCT.
typo: if -> is
I'd suggest to clarify that "any unnamed structure field" is really
any unnamed non-struct-or-union field, since anonymous inner structs
and unions certainly are prese
On 3/26/24 07:28, Cupertino Miranda wrote:
> Hi everyone,
>
> This patch is an expected fix for the issue reported by systemd in:
> https://github.com/systemd/systemd/issues/31888
> Also, Jose Marchesi opened the following bugzilla to report it:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114
Hi Jakub,
On 3/27/24 04:16, Jakub Jelinek wrote:
> On Wed, Mar 27, 2024 at 11:18:49AM +0100, Jakub Jelinek wrote:
>>> -/* The offset entry for each variable in a DATSEC should be 0 at compile
>>> time. */
>>> -/* { dg-final { scan-assembler-times "0\[\t \]+\[^\n\]*bts_offset" 7 } } */
>>> +/* Th
The behavior introduced in
fa60ac54964 btf: Emit labels in DATASEC bts_offset entries.
is only fully correct when compiling for the BPF target with BPF CO-RE
enabled. In other cases, depending on optimizations, it can result in
an incorrect symbol reference in the entry bts_offset field for a s
This test failed on powerpc --target_board=unix'{-m32}' because two
variables were not placed in sections where the test silently (and
incorrectly) assumed they would be.
The important thing for the test is only that BTF_KIND_DATASEC entries
are NOT generated for the extern variable declarations w
On 4/10/24 11:25, Indu Bhagat wrote:
> PR debug/112878: ICE: in ctf_add_slice, at ctfc.cc:499 with _BitInt > 255 in
> a struct and -gctf1
>
> The CTF generation in GCC does not have a mechanism to roll-back an
> already added type. In this testcase presented in the PR, we hit a
> representation
Hi Indu,
On 4/10/24 11:25, Indu Bhagat wrote:
> Testing the previous fix in gen_ctf_sou_type () reveals an issue in BTF
> generation, however: BTF emission was currently decrementing the vlen
> (indicating the number of members) to skip members of type CTF_K_UNKNOWN
> altogether, but still emittin
Hi Cupertino,
On 4/11/24 04:11, Cupertino Miranda wrote:
> Code was allocating way too much space for the string.
A little bit more description would not hurt. Perhaps you could say
something like:
"The BPF backend was allocating an unnecessarily large string when
constructing CO-RE relocations
This patch fixes an issue with mangled BTF that could occur when
a struct type contains a bitfield member which cannot be represented
in BTF. It is undefined what should happen in such cases, but we can
at least do something reasonable.
Commit
936dd627cd9 "btf: do not skip members of data type
On 4/11/24 13:40, Indu Bhagat wrote:
> On 4/11/24 11:53, David Faust wrote:
>> This patch fixes an issue with mangled BTF that could occur when
>> a struct type contains a bitfield member which cannot be represented
>> in BTF. It is undefined what should happen in such ca
[Changes from v1: use btf_dmd_representable_bitfield_p in
btf_asm_sou_member, instead of a slightly incorrect equivalent check.]
This patch fixes an issue with mangled BTF that could occur when
a struct type contains a bitfield member which cannot be represented
in BTF. It is undefined what shou
This patch fixes a small error that could occur in the debug comment
when emitting a type reference with btf_asm_type_ref.
While working on a previous patch, I noticed the following in the asm
output for the test btf-bitfields-4.c:
...
.long 0x39# MEMBER 'c' idx=3
.l
Commit 77d0f9ec3809b4d2e32c36069b6b9239d301c030 inadvertently changed
the normal asm dialect instruction template for zero_extendqidi2 from
ldxb to ldxh. Fix that.
Tested for bpf-unknown-none on x86_64-linux-gnu host.
gcc/
* config/bpf/bpf.md (zero_extendqidi2): Correct asm template to
BPF programs are not typically linked, which means we cannot fall back
on library calls to implement __builtin_{memmove,memcpy} and should
always expand them inline if possible.
GCC already successfully expands these builtins inline in many cases,
but failed to do so for a few for simple cases inv
[Changes from v1: Jose's review comments, all of which I agree with.
- Fix 'implments' typo in commit message.
- Change check that alignment is CONST_INT to gcc_assert ().
- Change default case in alignment switch to gcc_unreachable ().
- Reword error message for non-constant size memmove/memcp
On 2/20/24 02:24, Cupertino Miranda wrote:
> This patch correct the aditition of +1 on the type id, which originally
> was done in the wrong location and leaded to func_sts->dtd_type for
> BTF_KIND_FUNCS struct data to contain the type id of the previous entry.
>
> gcc/ChangeLog:
> * btfo
Hi Cupertino,
On 2/20/24 02:24, Cupertino Miranda wrote:
> Dissociated .BTF.ext from the CO-RE relocations creation. Improvement of
> allocation/deallocation of BTF structures. Moving deallocation to final
> when needed.
>
> gcc/ChangeLog:
>
> * config/bpf/bpf.cc (bpf_option_override): Mak
On 2/20/24 12:37, Jose E. Marchesi wrote:
>
> Hi Faust.
>
>> +bool
>> +bpf_expand_cpymem (rtx *operands, bool is_move)
>> +{
>> + /* Size must be constant for this expansion to work. */
>> + if (!CONST_INT_P (operands[2]))
>> +{
>> + const char *name = is_move ? "memmove" : "memcpy
[Changes from v2:
- Fix incorrectly passing a location instead of OPT_W* for warning ().
- Reword warning/error message and test accordingly. ]
[Changes from v1: Jose's review comments, all of which I agree with.
- Fix 'implments' typo in commit message.
- Change check that alignment is CON
On 2/20/24 02:24, Cupertino Miranda wrote:
> Added a traversal function to traverse all BTF_KIND_FUNC nodes with a
> callback function. Used for .BTF.ext section content creation.
>
> gcc/ChangeLog
>
> * btfout.cc (output_btf_func_types): use FOR_EACH_VEC_ELT.
> (traverse_btf_func_t
On 2/20/24 02:24, Cupertino Miranda wrote:
> gcc/ChangeLog:
> * config.gcc (target_gtfiles): changed coreout to btfext-out.
> (extra_objs): changed coreout to btfext-out.
I think these entries should start with a capital letter ("Changed...").
> * config/bpf/coreout.cc: Renam
Hi Cupertino,
Just some nits below. Apologies for incoming pedantry.
On 2/27/24 11:04, Cupertino Miranda wrote:
> This patch correct the aditition of +1 on the type id, which originally
> was done in the wrong location and leaded to func_sts->dtd_type for
> BTF_KIND_FUNCS struct data to contain t
Hi Cupertino,
Similar to patch 1, please use present tense to match the style of
existing commits, in commit message and in ChangeLog.
On 2/27/24 11:04, Cupertino Miranda wrote:
> Added a traversal function to traverse all BTF_KIND_FUNC nodes with a
> callback function. Used for .BTF.ext section
On 2/27/24 11:04, Cupertino Miranda wrote:
> BPF applications, when generating BTF information should always create a
> .BTF.ext section.
> Current implementation was only creating it when -mco-re option was used.
> This patch makes .BTF.ext always be generated for BPF target objects.
> The patc
On 2/27/24 11:04, Cupertino Miranda wrote:
> gcc/ChangeLog:
>
> * config.gcc (target_gtfiles): Changes coreout to btfext-out.
> (extra_objs): Changes coreout to btfext-out.
> * config/bpf/coreout.cc: Renamed to btfext-out.cc.
> * config/bpf/btfext-out.cc: Added.
> * c
Hi Cupertino,
On 2/27/24 11:04, Cupertino Miranda wrote:
> Kernel verifier complains in some particular cases for missing func_info
> implementation in .BTF.ext. This patch implements it.
>
> Strings are cached locally in coreout.cc to avoid adding duplicated
> strings in the string list. This st
Hi Cupertino,
On 1/8/24 02:55, Cupertino Miranda wrote:
> Hi everyone,
>
> This patch adds a comment to the BTF strings regarding their position
> within the section. This is useful for assembly inspection purposes.
>
> Regards,
> Cupertino
>
> When using -dA, this function was only printing as
Hi Cupetino,
On 1/8/24 03:05, Cupertino Miranda wrote:
> Hi everyone,
>
> This patch address the problem reported in:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113225
>
> Looking forward to your review.
LGTM, thanks. Please apply.
>
> Cheers,
> Cupertino
>
>
> This patch fix a problem
Hi Indu,
On 11/30/23 14:18, Indu Bhagat wrote:
> PR debug/112656 - btf: function prototypes generated with name
>
> With this patch, all BTF_KIND_FUNC_PROTO will appear anonymous in the
> generated BTF section.
>
> As noted in the discussion in the bugzilla, the number of
> BTF_KIND_FUNC_PROTO t
On 11/30/23 14:17, Indu Bhagat wrote:
> PR debug/112768 - btf: fix asm comment output for BTF_KIND_FUNC* kinds
>
> The patch adds a small function to abstract out the detail and return
> the name of the type. The patch also fixes the issue of BTF_KIND_FUNC
> appearing in the comments with a 'nu
The process of creating BTF_KIND_DATASEC records involves iterating
through variable declarations, determining which section they will be
placed in, and creating an entry in the appropriate DATASEC record
accordingly.
For variables without e.g. an explicit __attribute__((section)), we use
categori
On 12/5/23 13:28, Indu Bhagat wrote:
> On 12/4/23 15:47, David Faust wrote:
>> The process of creating BTF_KIND_DATASEC records involves iterating
>> through variable declarations, determining which section they will be
>> placed in, and creating an entry in the appro
The BTF specification does not formally define a representation for
forward-declared enum types such as:
enum Foo;
Forward-declarations for struct and union types are represented by
BTF_KIND_FWD, which has a 1-bit flag distinguishing the two.
The de-facto standard format used by other tools li
On 11/13/23 14:36, Cupertino Miranda wrote:
> gcc/ChangeLog:
> * config/bpf/core-builtins.cc (core_mark_as_access_index):
> Corrected check.
OK, thanks.
> ---
> gcc/config/bpf/core-builtins.cc | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/gcc/config/bpf
Hi Cupertino,
A couple of comments inline.
On 11/13/23 14:37, Cupertino Miranda wrote:
> This patch fixes a BTF, which would become invalid when having
> smaller then 4 byte definitions of enums.
> For example, when using the __attribute__((mode(byte))) in the enum
> definition.
Please add a tes
On 11/13/23 14:35, Cupertino Miranda wrote:
> The parser plugin handler that is responsible for collecting enum values
> information was being removed way too early.
> bpf_resolve_overloaded_core_builtin is called by the parser.
> It was moved to the function execute_lower_bpf_core.
>
OK, than
Hi Cupertino,
On 11/27/23 09:21, Cupertino Miranda wrote:
> Hi everyone,
>
> David: Thanks for the v1 review.
>
> This version adds the following;
> - test case,
> - improves condition logic,
> - fixes mask typo.
>
> Looking forward to your review.
v2 LGTM, please apply.
Thanks!
>
> v1 at
The BPF "pseudo-C" assembly dialect uses semi-colon (;) to separate
statements, not to begin line comments. The GNU assembler was recently
changed accordingly:
https://sourceware.org/pipermail/binutils/2023-November/130867.html
This patch adapts the BPF backend in GCC accordingly, to use a hash
I was not aware of the requirement to regenerate the opt urls files
when adding a new option until the autobuilder complained.
Regenerate common.opt.urls for the -gprune-btf option added in:
b8977d928a7a btf: add -gprune-btf option
Pushed as obvious.
gcc/
* common.opt.urls: Regenerate.
[This is a resend of a patch previously sent as:
PATCH v4 6/6 opts: allow any combination of DWARF,CTF,BTF
https://gcc.gnu.org/pipermail/gcc-patches/2024-June/654253.html]
Previously it was not supported to generate both CTF and BTF debug info
in the same compiler run, as both formats made i
On 7/15/24 08:33, Cupertino Miranda wrote:
> Both xchg and cmpxchg instructions, in the pseudo-C dialect, do not
> expect their memory address operand to be surrounded by parentheses.
> For example, it should be output as "w0 =cmpxchg32_32(r8+8,w0,w2)"
> instead of "w0 =cmpxchg32_32((r8+8),w0,w2)".
and on x86_64-linux-gnu host for
bpf-unknown-none target.
Also tested by compiling and runninng Linux kernel BPF selftests.
No known regressions.
David Faust (6):
ctf, btf: restructure CTF/BTF emission
ctf: use pointers instead of IDs internally
btf: refactor and simplify implementation
This commit makes some structural changes to the CTF/BTF debug info
emission. In particular:
a) CTF is new always fully generated and emitted before any
BTF-related procedures are run. This means that BTF-related
functions can change, even irreversibly, the shared in-memory
represen
This patch replaces all inter-type references in the ctfc internal data
structures with pointers, rather than the references-by-ID which were
used previously.
A couple of small updates in the BPF backend are included to make it
compatible with the change.
This change is only to the in-memory repr
This patch adds a new option, -fprune-btf, to control BTF debug info
generation.
As the name implies, this option enables a kind of "pruning" of the BTF
information before it is emitted. When enabled, rather than emitting
all type information translated from DWARF, only information for types
dire
Previously it was not supported to generate both CTF and BTF debug info
in the same compiler run, as both formats made incompatible changes to
the same internal data structures.
With the structural change in the prior patches, in particular the
guarantee that CTF will always be fully emitted befor
This patch enables -fprune-btf by default in the BPF backend when
generating BTF information, and fixes BPF CO-RE generation when using
-fprune-btf.
When generating BPF CO-RE information, we must ensure that types used
in CO-RE relocations always have sufficient BTF information emited so
that the
This patch heavily refactors btfout.cc to take advantage of the
structural changes in the prior commits.
Now that inter-type references are internally stored as simply pointers,
all the painful, brittle, confusing infrastructure that was used in the
process of converting CTF type IDs to BTF type I
On 5/31/24 00:07, Richard Biener wrote:
> On Thu, May 30, 2024 at 11:34 PM David Faust wrote:
>>
>> This patch adds a new option, -fprune-btf, to control BTF debug info
>> generation.
>
> Can you name it -gprune-btf instead?
Yes, sure.
I think I followed -felimin
On 8/7/24 10:19, Will Hawkins wrote:
> On Mon, Jul 29, 2024 at 2:14 PM David Faust wrote:
>>
>>
>> On 7/29/24 07:42, Will Hawkins wrote:
>>> If the user provides a kind value that is more than 5 bits, the
>>> BTF_KIND_INFO macro would emit incorrect value
generating both CTF and BTF in the same compiler run,
allowing for any combinaion of -gdwarf, -gctf and -gbtf.
Tested on x86_64-linux-gnu, and on x86_64-linux-gnu host for
bpf-unknown-none target.
Also tested by compiling and runninng Linux kernel BPF selftests.
No known regressions.
David Faust
This commit makes some structural changes to the CTF/BTF debug info
emission. In particular:
a) CTF is new always fully generated and emitted before any
BTF-related procedures are run. This means that BTF-related
functions can change, even irreversibly, the shared in-memory
represen
This patch enables -gprune-btf by default in the BPF backend when
generating BTF information, and fixes BPF CO-RE generation when using
-gprune-btf.
When generating BPF CO-RE information, we must ensure that types used
in CO-RE relocations always have sufficient BTF information emited so
that the
This patch heavily refactors btfout.cc to take advantage of the
structural changes in the prior commits.
Now that inter-type references are internally stored as simply pointers,
all the painful, brittle, confusing infrastructure that was used in the
process of converting CTF type IDs to BTF type I
This patch adds a new option, -gprune-btf, to control BTF debug info
generation.
As the name implies, this option enables a kind of "pruning" of the BTF
information before it is emitted. When enabled, rather than emitting
all type information translated from DWARF, only information for types
dire
This patch replaces all inter-type references in the ctfc internal data
structures with pointers, rather than the references-by-ID which were
used previously.
A couple of small updates in the BPF backend are included to make it
compatible with the change.
This change is only to the in-memory repr
Previously it was not supported to generate both CTF and BTF debug info
in the same compiler run, as both formats made incompatible changes to
the same internal data structures.
With the structural change in the prior patches, in particular the
guarantee that CTF will always be fully emitted befor
On 6/12/24 09:55, Jose E. Marchesi wrote:
>
> Hi Faust.
> Thanks for the patch.
> Please see a question below.
>
>> This patch enables -gprune-btf by default in the BPF backend when
>> generating BTF information, and fixes BPF CO-RE generation when using
>> -gprune-btf.
>>
>> When generating B
it.
Thanks!
archive: https://gcc.gnu.org/pipermail/gcc-patches/2024-June/654252.html
On 6/11/24 12:01, David Faust wrote:
> This patch adds a new option, -gprune-btf, to control BTF debug info
> generation.
>
> As the name implies, this option enables a kind of "pruning" of
Ping.
archive: https://gcc.gnu.org/pipermail/gcc-patches/2024-June/654253.html
On 6/11/24 12:01, David Faust wrote:
> Previously it was not supported to generate both CTF and BTF debug info
> in the same compiler run, as both formats made incompatible changes to
> the same inte
On 7/29/24 07:42, Will Hawkins wrote:
> If the user provides a kind value that is more than 5 bits, the
> BTF_KIND_INFO macro would emit incorrect values for info (by clobbering
> values of the kind flag).
>
> Tested on x86_64-redhat-linux.
OK, thanks.
>
> include/ChangeLog:
>
> * btf.
On 4/17/24 11:44, Cupertino Miranda wrote:
> The BPF backend was allocating an unnecessarily large string when
> constructing CO-RE relocations for enum types.
>
> gcc/ChangeLog:
> * config/bpf/core-builtins.cc (process_enum_value): Correct
> string allocation.
> ---
> gcc/config/b
Hi Cupertino,
On 4/18/24 13:58, Cupertino Miranda wrote:
> Hi David, everyone,
>
> Following Davids last review I decided to properly detect error cases,
> as suggested.
> The error however should be reported earlier in compilation in
> pack_enum_valud function, where all the errors are reported.
Compiling a BPF program with CO-RE relocations (and BTF) while also
passing -gtoggle led to an inconsistent state where CO-RE support was
enabled but BTF would not be generated, and this was not caught by the
existing option parsing. This led to an ICE when generating the CO-RE
relocation info, si
BTF is the standard debug info used with BPF programs, so it makes sense
to default to BTF rather than DWARF.
Tested on x86_64-linux-gnu host for bpf-unknown-none target.
gcc/
* config/bpf/bpf.h (PREFERRED_DEBUGGING_TYPE): Set to BTF_DEBUG.
gcc/testsuite/
* gcc.target/bpf/bpf-deb
rmation by a factor of 10.
Patch 6 makes BTF pruning work with BPF CO-RE, and enables the pruning
by default in the BPF backend.
Tested on x86_64-linux-gnu, and on x86_64-linux-gnu host for
bpf-unknown-none target.
Also heavily tested with Linux kernel BPF selftests.
No known regressions.
Davi
Previously it was not supported to generate both CTF and BTF debug info
in the same compiler run, as both formats made incompatible changes to
the same internal data structures.
With the structural change in the prior patch, in particular the
guarantee that CTF will always be fully emitted before
This commit makes some structural changes to the CTF/BTF debug info
emission. In particular:
a) CTF is new always fully generated and emitted before any
BTF-related procedures are run. This means that BTF-related
functions can change, even irreversibly, the shared in-memory
represen
This patch enables -fprune-btf by default in the BPF backend when
generating BTF information, and fixes BPF CO-RE generation when using
-fprune-btf.
When generating BPF CO-RE information, we must ensure that types used
in CO-RE relocations always have sufficient BTF information emited so
that the
This patch adds a new option, -fprune-btf, to control BTF debug info
generation.
As the name implies, this option enables a kind of "pruning" of the BTF
information before it is emitted. When enabled, rather than emitting
all type information translated from DWARF, only information for types
dire
This patch replaces all inter-type references in the ctfc internal data
structures with pointers, rather than the references-by-ID which were
used previously.
A couple of small updates in the BPF backend are included to make it
compatible with the change.
This change is only to the in-memory repr
This patch heavily refactors btfout.cc to take advantage of the
structural changes in the prior commits.
Now that inter-type references are internally stored as simply pointers,
all the painful, brittle, confusing infrastructure that was used in the
process of converting CTF type IDs to BTF type I
On 5/1/24 12:15, David Faust wrote:
> This patch replaces all inter-type references in the ctfc internal data
> structures with pointers, rather than the references-by-ID which were
> used previously.
>
> A couple of small updates in the BPF backend are included to make it
> c
This commit makes some structural changes to the CTF/BTF debug info
emission. In particular:
a) CTF is new always fully generated and emitted before any
BTF-related procedures are run. This means that BTF-related
functions can change, even irreversibly, the shared in-memory
represen
makes BTF pruning work with BPF CO-RE, and enables the pruning
by default in the BPF backend.
Tested on x86_64-linux-gnu, and on x86_64-linux-gnu host for
bpf-unknown-none target.
Also heavily tested with Linux kernel BPF selftests.
No known regressions.
David Faust (6):
ctf, btf: restructu
This patch replaces all inter-type references in the ctfc internal data
structures with pointers, rather than the references-by-ID which were
used previously.
A couple of small updates in the BPF backend are included to make it
compatible with the change.
This change is only to the in-memory repr
Previously it was not supported to generate both CTF and BTF debug info
in the same compiler run, as both formats made incompatible changes to
the same internal data structures.
With the structural change in the prior patch, in particular the
guarantee that CTF will always be fully emitted before
This patch adds a new option, -fprune-btf, to control BTF debug info
generation.
As the name implies, this option enables a kind of "pruning" of the BTF
information before it is emitted. When enabled, rather than emitting
all type information translated from DWARF, only information for types
dire
This patch heavily refactors btfout.cc to take advantage of the
structural changes in the prior commits.
Now that inter-type references are internally stored as simply pointers,
all the painful, brittle, confusing infrastructure that was used in the
process of converting CTF type IDs to BTF type I
This patch enables -fprune-btf by default in the BPF backend when
generating BTF information, and fixes BPF CO-RE generation when using
-fprune-btf.
When generating BPF CO-RE information, we must ensure that types used
in CO-RE relocations always have sufficient BTF information emited so
that the
On 5/3/24 2:02 PM, Indu Bhagat wrote:
> On 5/2/24 10:11, David Faust wrote:
>> This commit makes some structural changes to the CTF/BTF debug info
>> emission. In particular:
>>
>> a) CTF is new always fully generated and emitted before any
>> BTF-relate
On 10/14/24 11:04, Cupertino Miranda wrote:
> Hi everyone,
>
> Here is the v2 for the patch in this thread:
> https://gcc.gnu.org/pipermail/gcc-patches/2024-October/665378.html
> Please noticed that commit message was adapted to new content.
>
> Regards,
> Cupertino
Hi Cupertino,
Thanks for
Translate DW_TAG_GNU_annotation DIEs created for C attributes
btf_decl_tag and btf_type_tag into an in-memory representation in the
CTF/BTF container. They will be output in BTF as BTF_KIND_DECL_TAG and
BTF_KIND_TYPE_TAG records.
The new CTF kinds used to represent these annotations, CTF_K_DECL_T
Add two new c-family attributes, "btf_decl_tag" and "btf_type_tag" along
with a simple shared handler for them.
gcc/c-family/
* c-attribs.cc (c_common_attribute_table): Add btf_decl_tag and
btf_type_tag attributes.
(handle_btf_tag_attribute): New handler for both new attri
gcc/
* doc/extend.texi (Common Variable Attributes): Document new
btf_decl_tag attribute.
(Common Type Attributes): Document new btf_type_tag attribute.
---
gcc/doc/extend.texi | 68 +
1 file changed, 68 insertions(+)
diff --git
Support the btf_decl_tag and btf_type_tag attributes in BTF by creating
and emitting BTF_KIND_DECL_TAG and BTF_KIND_TYPE_TAG records,
respectively, for them.
Some care is required when -gprune-btf is in effect to avoid emitting
decl or type tags for declarations or types which have been pruned and
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