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Cranelift: Avoid calling ensure_struct_return_pointer_is_returned and cloning sigs for every call (#5113)

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* Cranelift: pass iterators to `ABIMachineSpec::compute_arg_locs`

Instead of slices. This gives us more flexibility to pass custom sequences
without needing to allocate a `Vec` to hold them and pass in as a slice.

* Cranelift: Avoid cloning `ir::Signature`s in `SigData::from_func_sig`

This avoids two heap allocations per signature that are unnecessary 99% of the
time.

* fix typo

* Simplify condition in `missing_struct_return`
This commit is contained in:
Nick Fitzgerald
2022-10-24 17:21:34 -07:00
committed by GitHub
parent ec12415b1f
commit 097d1087e0
1 changed files with 21 additions and 14 deletions
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35
cranelift/codegen/src/machinst/abi.rs
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@@ -586,14 +586,15 @@ impl SigData {
sig: &ir::Signature, sig: &ir::Signature,
flags: &settings::Flags, flags: &settings::Flags,
) -> CodegenResult<SigData> { ) -> CodegenResult<SigData> {
let sig = ensure_struct_return_ptr_is_returned(sig); let sret = missing_struct_return(sig);
let returns = sret.as_ref().into_iter().chain(&sig.returns);
// Compute args and retvals from signature. Handle retvals first, // Compute args and retvals from signature. Handle retvals first,
// because we may need to add a return-area arg to the args. // because we may need to add a return-area arg to the args.
let (rets, sized_stack_ret_space, _) = M::compute_arg_locs( let (rets, sized_stack_ret_space, _) = M::compute_arg_locs(
sig.call_conv, sig.call_conv,
flags, flags,
&sig.returns, returns,
ArgsOrRets::Rets, ArgsOrRets::Rets,
/* extra ret-area ptr = */ false, /* extra ret-area ptr = */ false,
)?; )?;
@@ -1175,19 +1176,21 @@ fn gen_store_stack_multi<M: ABIMachineSpec>(
ret ret
} }
pub(crate) fn ensure_struct_return_ptr_is_returned(sig: &ir::Signature) -> ir::Signature { /// If the signature needs to be legalized, then return the struct-return
let params_structret = sig /// parameter that should be prepended to its returns. Otherwise, return `None`.
.params fn missing_struct_return(sig: &ir::Signature) -> Option<ir::AbiParam> {
.iter() let struct_ret_index = sig.special_param_index(ArgumentPurpose::StructReturn)?;
.find(|p| p.purpose == ArgumentPurpose::StructReturn); if !sig.uses_special_return(ArgumentPurpose::StructReturn) {
let rets_have_structret = sig.returns.len() > 0 return Some(sig.params[struct_ret_index]);
&& sig }
.returns
.iter() None
.any(|arg| arg.purpose == ArgumentPurpose::StructReturn); }
fn ensure_struct_return_ptr_is_returned(sig: &ir::Signature) -> ir::Signature {
let mut sig = sig.clone(); let mut sig = sig.clone();
if params_structret.is_some() && !rets_have_structret { if let Some(sret) = missing_struct_return(&sig) {
sig.returns.insert(0, params_structret.unwrap().clone()); sig.returns.insert(0, sret);
} }
sig sig
} }
@@ -1198,6 +1201,10 @@ pub(crate) fn ensure_struct_return_ptr_is_returned(sig: &ir::Signature) -> ir::S
impl<M: ABIMachineSpec> Callee<M> { impl<M: ABIMachineSpec> Callee<M> {
/// Access the (possibly legalized) signature. /// Access the (possibly legalized) signature.
pub fn signature(&self) -> &ir::Signature { pub fn signature(&self) -> &ir::Signature {
debug_assert!(
missing_struct_return(&self.ir_sig).is_none(),
"`Callee::ir_sig` is always legalized"
);
&self.ir_sig &self.ir_sig
} }