On 1/14/21 2:21 PM, Sedat Dilek wrote:
On Thu, Jan 14, 2021 at 11:05 PM Nick Desaulniers
<ndesaulniers@xxxxxxxxxx> wrote:
On Thu, Jan 14, 2021 at 1:52 PM Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote:
Today, I have observed and reported (see [1]) bpf/btf/pahole issues
with Clang v12 (from apt.llvm.org) and DWARF-4 ("four").
Cannot speak for other compilers and its version.
If these are not specific to DWARF5, then it sounds like
CONFIG_DEBUG_INFO_DWARF4 should also be marked as `depends on
!DEBUG_INFO_BTF`? (or !BTF && CC=clang)
My experiments yesterday on Wednesday were with GCC v10.2.1 plus LLVM=1.
There were no issues with DWARF v2 and v4 but v5.
Unfortunately, build-time is long here on my systems.
For now, I did CONFIG_DEBUG_INFO_BTF=n.
I have applied attached patch.
Is it possible to re-arrange CC depends?
[ /lib/Kconfig.debug ]
config DEBUG_INFO_DWARF5
bool "Generate DWARF Version 5 debuginfo"
- depends on GCC_VERSION >= 50000 || CC_IS_CLANG
- depends on CC_IS_GCC ||
$(success,$(srctree)/scripts/test_dwarf5_support.sh $(CC)
$(CLANG_FLAGS))
+ depends on CC_IS_GCC && GCC_VERSION >= 50000 || CC_IS_CLANG
+ depends on $(success,$(srctree)/scripts/test_dwarf5_support.sh
$(CC) $(CLANG_FLAGS))
+ depends on !DEBUG_INFO_BTF
help
Generate DWARF v5 debug info. Requires binutils 2.35, gcc 5.0+ (gcc
5.0+ accepts the -gdwarf-5 flag but only had partial support for some
And adding text to help concerning DEBUG_INFO_BTF is no good these days.
Thanks, the above change looks good to me as well as the suggestion to
add some explanation why disabling DEBUG_INFO_BTF.
BTW, if you do not mind:
Label your patches with "*k*build:" not "*K*build:".
Use "DWARF *v*ersion" not "DWARF *V*ersion" - everywhere.
One patch missed the label "kbuild:" (guess the subject has too many
characters).
From what I remember - but these are small nits.
Thanks for DWARF v5 support in Linux.
- Sedat -
- Sedat -
[1] https://lore.kernel.org/bpf/CA+icZUWb3OyaSQAso8LhsRifZnpxAfDtuRwgB786qEJ3GQ+kRw@xxxxxxxxxxxxxx/T/#m6d05cc6c634e9cee89060b2522abc78c3705ea4c
--
Thanks,
~Nick Desaulniers
