Messages in this thread | | | Date | Thu, 4 Feb 2021 19:07:41 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | ANNOUNCE: pahole v1.20 (gcc11 DWARF5's default, lots of ELF sections, BTF) |
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Hi,
The v1.20 release of pahole and its friends is out, mostly addressing problems related to gcc 11 defaulting to DWARF5 for -g, available at the usual places:
Main git repo:
git://git.kernel.org/pub/scm/devel/pahole/pahole.git
Mirror git repo:
https://github.com/acmel/dwarves.git
tarball + gpg signature:
https://fedorapeople.org/~acme/dwarves/dwarves-1.20.tar.xz https://fedorapeople.org/~acme/dwarves/dwarves-1.20.tar.bz2 https://fedorapeople.org/~acme/dwarves/dwarves-1.20.tar.sign
Best Regards,
- Arnaldo
v1.20:
BTF encoder:
- Improve ELF error reporting using elf_errmsg(elf_errno()).
- Improve objcopy error handling.
- Fix handling of 'restrict' qualifier, that was being treated as a 'const'.
- Support SHN_XINDEX in st_shndx symbol indexes, to handle ELF objects with more than 65534 sections, for instance, which happens with kernels built with 'KCFLAGS="-ffunction-sections -fdata-sections", Other cases may include when using FG-ASLR, LTO.
- Cope with functions without a name, as seen sometimes when building kernel images with some versions of clang, when a SEGFAULT was taking place.
- Fix BTF variable generation for kernel modules, not skipping variables at offset zero.
- Fix address size to match what is in the ELF file being processed, to fix using a 64-bit pahole binary to generate BTF for a 32-bit vmlinux image.
- Use kernel module ftrace addresses when finding which functions to encode, which increases the number of functions encoded.
libbpf:
- Allow use of packaged version, for distros wanting to dynamically link with the system's libbpf package instead of using the libbpf git submodule shipped in pahole's source code.
DWARF loader:
- Support DW_AT_data_bit_offset
This appeared in DWARF4 but is supported only in gcc's -gdwarf-5, support it in a way that makes the output be the same for both cases.
$ gcc -gdwarf-5 -c examples/dwarf5/bf.c $ pahole bf.o struct pea { long int a:1; /* 0: 0 8 */ long int b:1; /* 0: 1 8 */ long int c:1; /* 0: 2 8 */
/* XXX 29 bits hole, try to pack */ /* Bitfield combined with next fields */
int after_bitfield; /* 4 4 */
/* size: 8, cachelines: 1, members: 4 */ /* sum members: 4 */ /* sum bitfield members: 3 bits, bit holes: 1, sum bit holes: 29 bits */ /* last cacheline: 8 bytes */ };
- DW_FORM_implicit_const in attr_numeric() and attr_offset()
- Support DW_TAG_GNU_call_site, its the standardized rename of the previously supported DW_TAG_GNU_call_site.
build:
- Fix compilation on 32-bit architectures.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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