https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91101
--- Comment #10 from Martin Liška <marxin at gcc dot gnu.org> ---
The issue is that __asan_stack_malloc_0 function is very high in perf profile:
# Overhead Command Shared Object Symbol
# ........ ............... ........................
........................................................................
#
91.97% test-conf-parse libasan.so.5.0.0 [.]
__asan_stack_malloc_0
7.00% test-conf-parse libsystemd-shared-242.so [.] config_parse
0.12% test-conf-parse libsystemd-shared-242.so [.] read_line_full
0.11% test-conf-parse libc-2.29.so [.] _IO_getc
0.10% test-conf-parse libc-2.29.so [.] __strlen_avx2
0.08% test-conf-parse libsystemd-shared-242.so [.] safe_fgetc
0.07% test-conf-parse libsystemd-shared-242.so [.] categorize_eol
perf annotate says:
: Disassembly of section .text:
:
: 0000000000034a00 <__asan_stack_malloc_0>:
: __asan_stack_malloc_0():
: extern "C" SANITIZER_INTERFACE_ATTRIBUTE void
__asan_stack_free_##class_id( \
: uptr ptr, uptr size) {
\
: OnFree(ptr, class_id, size);
\
: }
...
: _ZN6__asan9FakeStack8AllocateEmmm():
: GC(real_stack);
0.00 : 34b30: mov %rbp,%rsi
0.00 : 34b33: mov %rax,%rdi
0.00 : 34b36: callq 34800 <__asan::FakeStack::GC(unsigned long)>
0.00 : 34b3b: jmpq 34a2c <__asan_stack_malloc_0+0x2c>
: for (int i = 0; i < num_iter; i++) {
0.00 : 34b40: xor %ecx,%ecx
0.12 : 34b42: add $0x1,%ecx
17.35 : 34b45: cmp %ecx,%r8d
17.95 : 34b48: je 34b70 <__asan_stack_malloc_0+0x170>
: uptr pos = ModuloNumberOfFrames(stack_size_log,
class_id, hint_position++);
0.00 : 34b4a: mov %rdx,%rax
0.01 : 34b4d: add $0x1,%rdx
: _ZN6__asan9FakeStack20ModuloNumberOfFramesEmmm():
: return n & (NumberOfFrames(stack_size_log, class_id) -
1);
0.01 : 34b51: and %rsi,%rax
: _ZN6__asan9FakeStack8AllocateEmmm():
0.03 : 34b54: mov %rdx,(%rbx)
: if (flags[pos]) continue;
0.10 : 34b57: lea 0x1000(%rbx,%rax,1),%rdi
31.71 : 34b5f: cmpb $0x0,(%rdi)
32.65 : 34b62: je 34a72 <__asan_stack_malloc_0+0x72>
0.00 : 34b68: jmp 34b42 <__asan_stack_malloc_0+0x142>
0.00 : 34b6a: nopw 0x0(%rax,%rax,1)
