https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101726
Bug ID: 101726
Summary: target_clone resolver does not generate PIC despite
-fPIC
Product: gcc
Version: 11.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: stefan.kneifel at bluewin dot ch
Target Milestone: ---
Created attachment 51243
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51243&action=edit
Testcase: compile with -Os -fPIC
When compiling code using target_clones with -fPIC, the automatically generated
resolver refers to all the explicit targets correctly using
R_X86_64_REX_GOTPCRELX, whereas it refers to the default target incorrectly
using R_X86_64_PC32, resulting in an object file not linkable into a shared
library.
Compile the attached test.ii with:
gcc -Os -pipe -fPIC -c test.ii
and disassemble the output with:
objdump -rd test.o
--------------------------------------------
test.o: file format elf64-x86-64
Disassembly of section .text:
0000000000000000 <_Z3barv>:
0: e9 00 00 00 00 jmpq 5 <_Z3barv+0x5>
1: R_X86_64_PLT32 _Z3foov-0x4
Disassembly of section .text._Z3foov.resolver:
0000000000000000 <_Z3foov.resolver>:
0: 51 push %rcx
1: e8 00 00 00 00 callq 6 <_Z3foov.resolver+0x6>
2: R_X86_64_PLT32 __cpu_indicator_init-0x4
6: 48 8b 05 00 00 00 00 mov 0x0(%rip),%rax # d
<_Z3foov.resolver+0xd>
9: R_X86_64_REX_GOTPCRELX __cpu_model-0x4
d: 8b 50 0c mov 0xc(%rax),%edx
10: 0f ba e2 0f bt $0xf,%edx
14: 73 09 jae 1f <_Z3foov.resolver+0x1f>
16: 48 8b 05 00 00 00 00 mov 0x0(%rip),%rax # 1d
<_Z3foov.resolver+0x1d>
19: R_X86_64_REX_GOTPCRELX _Z3foov.avx512f.0-0x4
1d: eb 23 jmp 42 <_Z3foov.resolver+0x42>
1f: 0f ba e2 0a bt $0xa,%edx
23: 73 09 jae 2e <_Z3foov.resolver+0x2e>
25: 48 8b 05 00 00 00 00 mov 0x0(%rip),%rax # 2c
<_Z3foov.resolver+0x2c>
28: R_X86_64_REX_GOTPCRELX _Z3foov.avx2.1-0x4
2c: eb 14 jmp 42 <_Z3foov.resolver+0x42>
2e: 0f ba e2 09 bt $0x9,%edx
32: 48 8d 05 00 00 00 00 lea 0x0(%rip),%rax # 39
<_Z3foov.resolver+0x39>
35: R_X86_64_PC32 _Z3foov.default.3-0x4
39: 73 07 jae 42 <_Z3foov.resolver+0x42>
3b: 48 8b 05 00 00 00 00 mov 0x0(%rip),%rax # 42
<_Z3foov.resolver+0x42>
3e: R_X86_64_REX_GOTPCRELX _Z3foov.avx.2-0x4
42: 5a pop %rdx
43: c3 retq
--------------------------------------------
This should be consistent, and _Z3foov.default.3 should also be read from the
GOT.
