https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124212
Bug ID: 124212
Summary: jobserver token isn't preserved
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: driver
Assignee: unassigned at gcc dot gnu.org
Reporter: sjames at gcc dot gnu.org
Target Milestone: ---
gcc's jobserver_info in gcc/opts-jobserver.h doesn't record the token received.
In gcc/opts-common.cc:
```
void
jobserver_info::return_token ()
{
int fd = pipe_path.empty () ? wfd : pipefd;
char c = 'G';
int res = write (fd, &c, 1);
gcc_assert (res == 1);
}
```
Per https://www.gnu.org/software/make/manual/html_node/POSIX-Jobserver.html,
clients should return the exact token they received, not uniformly 'G':
"""
It’s important that when you release the job slot, you write back the same
character you read. Don’t assume that all tokens are the same character;
different characters may have different meanings to GNU make. The order is not
important, since make has no idea in what order jobs will complete anyway.
"""
