runtime·findfunc(uintptr addr)
{
Func *f;
int32 nf, n;
// Use atomic double-checked locking,
// because when called from pprof signal
// handler, findfunc must run without
// grabbing any locks.
// (Before enabling the signal handler,
// SetCPUProfileRate calls findfunc to trigger
// the initialization outside the handler.)
// Avoid deadlock on fault during malloc
// by not calling buildfuncs if we're already in malloc.
if(!m->mallocing && !m->gcing) {
if(runtime·atomicload(&funcinit) == 0) {
runtime·lock(&funclock);
if(funcinit == 0) {
buildfuncs();
runtime·atomicstore(&funcinit, 1);
}
runtime·unlock(&funclock);
}
}
if(nfunc == 0)
return nil;
if(addr < func[0].entry || addr >= func[nfunc].entry)
return nil;
// binary search to find func with entry <= addr.
f = func;
nf = nfunc;
while(nf > 0) {
n = nf/2;
if(f[n].entry <= addr && addr < f[n+1].entry)
return &f[n];
else if(addr < f[n].entry)
nf = n;
else {
f += n+1;
nf -= n+1;
}
}
// can't get here -- we already checked above
// that the address was in the table bounds.
// this can only happen if the table isn't sorted
// by address or if the binary search above is buggy.
runtime·prints("findfunc unreachable\n");
return nil;
}
Func*
findfunc(uintptr addr)
{
Func *f;
int32 nf, n;
lock(&funclock);
if(func == nil)
buildfuncs();
unlock(&funclock);
if(nfunc == 0)
return nil;
if(addr < func[0].entry || addr >= func[nfunc].entry)
return nil;
// binary search to find func with entry <= addr.
f = func;
nf = nfunc;
while(nf > 0) {
n = nf/2;
if(f[n].entry <= addr && addr < f[n+1].entry)
return &f[n];
else if(addr < f[n].entry)
nf = n;
else {
f += n+1;
nf -= n+1;
}
}
// can't get here -- we already checked above
// that the address was in the table bounds.
// this can only happen if the table isn't sorted
// by address or if the binary search above is buggy.
prints("findfunc unreachable\n");
return nil;
}
