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Cranelift: Simplify leaf functions that do not use the stack (#2960)

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* Cranelift AArch64: Simplify leaf functions that do not use the stack

Leaf functions that do not use the stack (e.g. do not clobber any
callee-saved registers) do not need a frame record.

Copyright (c) 2021, Arm Limited.
This commit is contained in:
Anton Kirilov
2021-08-27 11:12:37 +01:00
committed by GitHub
parent 12515e6646
commit 7b98be1bee
34 changed files with 650 additions and 1385 deletions
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48
cranelift/codegen/src/isa/arm32/abi.rs
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@@ -316,8 +316,9 @@ impl ABIMachineSpec for Arm32MachineDeps {
/// nominal SP offset; caller will do that.
fn gen_clobber_save(
_call_conv: isa::CallConv,
_setup_frame: bool,
_flags: &settings::Flags,
clobbers: &Set<Writable<RealReg>>,
clobbered_callee_saves: &Vec<Writable<RealReg>>,
fixed_frame_storage_size: u32,
_outgoing_args_size: u32,
) -> (u64, SmallVec<[Inst; 16]>) {
@@ -325,8 +326,7 @@ impl ABIMachineSpec for Arm32MachineDeps {
if fixed_frame_storage_size > 0 {
insts.extend(Self::gen_sp_reg_adjust(-(fixed_frame_storage_size as i32)).into_iter());
}
let clobbered_vec = get_callee_saves(clobbers);
let mut clobbered_vec: Vec<_> = clobbered_vec
let mut clobbered_vec: Vec<_> = clobbered_callee_saves
.into_iter()
.map(|r| r.to_reg().to_reg())
.collect();
@@ -345,14 +345,14 @@ impl ABIMachineSpec for Arm32MachineDeps {
}
fn gen_clobber_restore(
_call_conv: isa::CallConv,
call_conv: isa::CallConv,
_flags: &settings::Flags,
clobbers: &Set<Writable<RealReg>>,
_fixed_frame_storage_size: u32,
_outgoing_args_size: u32,
) -> SmallVec<[Inst; 16]> {
let mut insts = SmallVec::new();
let clobbered_vec = get_callee_saves(clobbers);
let clobbered_vec = Self::get_clobbered_callee_saves(call_conv, clobbers);
let mut clobbered_vec: Vec<_> = clobbered_vec
.into_iter()
.map(|r| Writable::from_reg(r.to_reg().to_reg()))
@@ -468,6 +468,31 @@ impl ABIMachineSpec for Arm32MachineDeps {
) -> ir::ArgumentExtension {
specified
}
fn get_clobbered_callee_saves(
_call_conv: isa::CallConv,
regs: &Set<Writable<RealReg>>,
) -> Vec<Writable<RealReg>> {
let mut ret = Vec::new();
for &reg in regs.iter() {
if is_callee_save(reg.to_reg()) {
ret.push(reg);
}
}
// Sort registers for deterministic code output.
ret.sort_by_key(|r| r.to_reg().get_index());
ret
}
fn is_frame_setup_needed(
_is_leaf: bool,
_stack_args_size: u32,
_num_clobbered_callee_saves: usize,
_fixed_frame_storage_size: u32,
) -> bool {
true
}
}
fn is_callee_save(r: RealReg) -> bool {
@@ -475,19 +500,6 @@ fn is_callee_save(r: RealReg) -> bool {
4 <= enc && enc <= 10
}
fn get_callee_saves(regs: &Set<Writable<RealReg>>) -> Vec<Writable<RealReg>> {
let mut ret = Vec::new();
for &reg in regs.iter() {
if is_callee_save(reg.to_reg()) {
ret.push(reg);
}
}
// Sort registers for deterministic code output.
ret.sort_by_key(|r| r.to_reg().get_index());
ret
}
fn is_reg_clobbered_by_call(r: RealReg) -> bool {
let enc = r.get_hw_encoding();
enc <= 3