Add comment to explain the code added by 41ce391c

Add a comment in arm-gen.c to explain how commit 41ce391c86df135609af33658414d4d452c5beb3 solves the register corruption when passing a structure in a function call.

Thomas Preud'homme committed 12 years ago

Commit 82b257c1 parent 48fc7461 file · +4 −1Browse files

Unified · Split

arm-gen.c+4−1

@@ -1127,7 +1127,10 @@ static int copy_params(int nb_args, struct plan *plan, int todo) · 1126 unmodified lines
1127	1127	for(pplan = plan->clsplans[CORE_STRUCT_CLASS]; pplan; pplan = pplan->prev) {
1128	1128	int r;
1129	1129	pplan->sval->r = pplan->start;
1130		− /* TODO: why adding fake param */
	1130	+ /* An SValue can only pin 2 registers at best (r and r2) but a structure
	1131	+ can occupy more than 2 registers. Thus, we need to push on the value
	1132	+ stack some fake parameter to have on SValue for each registers used
	1133	+ by a structure (r2 is not used). */
1131	1134	for (r = pplan->start + 1; r <= pplan->end; r++) {
1132	1135	if (todo & (1 << r)) {
1133	1136	nb_extra_sval++;