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cranelift: Only emit stack maps when a function actually uses reference types

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This fix avoids a small slow down in scenarios where reference types are enabled
but a given function doesn't actually use them.

Fixes #1883
This commit is contained in:
Nick Fitzgerald
2020-08-07 11:50:05 -07:00
parent 94e4bad1e0
commit 5af47dc4cd
1 changed files with 16 additions and 11 deletions
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21
cranelift/codegen/src/regalloc/context.rs
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@@ -203,17 +203,22 @@ impl Context {
&mut self.tracker,
);
// This function runs after register allocation has taken
// place, meaning values have locations assigned already.
if isa.flags().enable_safepoints() {
emit_stack_maps(func, domtree, &self.liveness, &mut self.tracker, isa);
} else {
// Make sure no references are used.
// If there are any reference types used, encode safepoints and emit
// stack maps.
//
// This function runs after register allocation has taken place, meaning
// values have locations assigned already, which is necessary for
// creating the stack maps.
let safepoints_enabled = isa.flags().enable_safepoints();
for val in func.dfg.values() {
let ty = func.dfg.value_type(val);
if ty.lane_type().is_ref() {
panic!("reference types were found but safepoints were not enabled.");
}
assert!(
safepoints_enabled,
"reference types were found but safepoints were not enabled"
);
emit_stack_maps(func, domtree, &self.liveness, &mut self.tracker, isa);
break;
}
}