https://sourceware.org/bugzilla/show_bug.cgi?id=29517
--- Comment #7 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Tom de Vries <vr...@sourceware.org>: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=1d45d90934b10862c00a22bcf4075815a785001b commit 1d45d90934b10862c00a22bcf4075815a785001b Author: Tom de Vries <tdevr...@suse.de> Date: Mon Oct 16 16:32:28 2023 +0200 [gdb/symtab] Work around PR gas/29517 When using glibc debuginfo generated with gas 2.39, we run into PR gas/29517: ... $ gdb -q -batch a.out -ex start -ex "p (char *)strstr (\"haha\", \"ah\")" Temporary breakpoint 1 at 0x40051b: file hello.c, line 6. Temporary breakpoint 1, main () at hello.c:6 6 printf ("hello\n"); Invalid cast. ... while without glibc debuginfo installed we get the expected result: ... $n = 0x7ffff7daa1b1 "aha" ... and likewise with glibc debuginfo generated with gas 2.40. The strstr ifunc resolves to __strstr_sse2_unaligned. The problem is that gas generates dwarf that states that the return type is void: ... <1><3e1e58>: Abbrev Number: 2 (DW_TAG_subprogram) <3e1e59> DW_AT_name : __strstr_sse2_unaligned <3e1e5d> DW_AT_external : 1 <3e1e5e> DW_AT_low_pc : 0xbbd2e <3e1e66> DW_AT_high_pc : 0xbc1c3 ... while the return type should be a DW_TAG_unspecified_type, as is the case with gas 2.40. We can still use the workaround of casting to another function type for both __strstr_sse2_unaligned: ... (gdb) p ((char * (*) (const char *, const char *))__strstr_sse2_unaligned) \ ("haha", "ah") $n = 0x7ffff7daa211 "aha" ... and strstr (which requires using *strstr to dereference the ifunc before we cast): ... gdb) p ((char * (*) (const char *, const char *))*strstr) ("haha", "ah") $n = 0x7ffff7daa251 "aha" ... but that's a bit cumbersome to use. Work around this in the dwarf reader, such that we have instead: ... (gdb) p (char *)strstr ("haha", "ah") $n = 0x7ffff7daa1b1 "aha" ... This also requires fixing producer_is_gcc to stop returning true for producer "GNU AS 2.39.0". Tested on x86_64-linux. Approved-By: Andrew Burgess <aburg...@redhat.com> PR symtab/30911 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30911 -- You are receiving this mail because: You are on the CC list for the bug.
