https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120071
Bug ID: 120071
Summary: Add builtin to get the current PC/instruction counter
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
The linux kernel does this brokenness thing:
include/linux/instruction_pointer.h:#define _THIS_IP_ ({ __label__ __here;
__here: (unsigned long)&&__here; })
It works on x86_64 because they define it correctly:
arch/x86/include/asm/linkage.h:#define _THIS_IP_ ({ unsigned long __here; asm
("lea 0(%%rip), %0" : "=r" (__here)); __here; })
But really GCC should provide a builtin to the same thing.
For targets like ppc, it is harder to do it and requires a jump but that is ok.
This is used for tracing so ...
See also the LLVM bug report:
https://github.com/llvm/llvm-project/issues/138272
