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Cranelift: update to latest regalloc2: (#4324)

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- Handle call instructions' clobbers with the clobbers API, using RA2's
  clobbers bitmask (bytecodealliance/regalloc2#58) rather than clobbers
  list;

- Pull in changes from bytecodealliance/regalloc2#59 for much more sane
  edge-case behavior w.r.t. liverange splitting.
This commit is contained in:
Chris Fallin
2022-06-28 09:01:59 -07:00
committed by GitHub
parent 66b829b1bf
commit b2e28b917a
21 changed files with 402 additions and 293 deletions
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152
cranelift/codegen/src/isa/aarch64/abi.rs
View File

@@ -14,7 +14,7 @@ use crate::settings;
use crate::{CodegenError, CodegenResult};
use alloc::boxed::Box;
use alloc::vec::Vec;
use regalloc2::VReg;
use regalloc2::{PRegSet, VReg};
use smallvec::{smallvec, SmallVec};
// We use a generic implementation that factors out AArch64 and x64 ABI commonalities, because
@@ -1062,8 +1062,9 @@ impl ABIMachineSpec for AArch64MachineDeps {
fn gen_call(
dest: &CallDest,
uses: Vec<Reg>,
defs: Vec<Writable<Reg>>,
uses: SmallVec<[Reg; 8]>,
defs: SmallVec<[Writable<Reg>; 8]>,
clobbers: PRegSet,
opcode: ir::Opcode,
tmp: Writable<Reg>,
callee_conv: isa::CallConv,
@@ -1076,6 +1077,7 @@ impl ABIMachineSpec for AArch64MachineDeps {
dest: name.clone(),
uses,
defs,
clobbers,
opcode,
caller_callconv: caller_conv,
callee_callconv: callee_conv,
@@ -1092,6 +1094,7 @@ impl ABIMachineSpec for AArch64MachineDeps {
rn: tmp.to_reg(),
uses,
defs,
clobbers,
opcode,
caller_callconv: caller_conv,
callee_callconv: callee_conv,
@@ -1103,6 +1106,7 @@ impl ABIMachineSpec for AArch64MachineDeps {
rn: *reg,
uses,
defs,
clobbers,
opcode,
caller_callconv: caller_conv,
callee_callconv: callee_conv,
@@ -1131,8 +1135,9 @@ impl ABIMachineSpec for AArch64MachineDeps {
insts.push(Inst::Call {
info: Box::new(CallInfo {
dest: ExternalName::LibCall(LibCall::Memcpy),
uses: vec![arg0.to_reg(), arg1.to_reg(), arg2.to_reg()],
defs: Self::get_regs_clobbered_by_call(call_conv),
uses: smallvec![arg0.to_reg(), arg1.to_reg(), arg2.to_reg()],
defs: smallvec![],
clobbers: Self::get_regs_clobbered_by_call(call_conv),
opcode: Opcode::Call,
caller_callconv: call_conv,
callee_callconv: call_conv,
@@ -1159,21 +1164,19 @@ impl ABIMachineSpec for AArch64MachineDeps {
s.nominal_sp_to_fp
}
fn get_regs_clobbered_by_call(call_conv_of_callee: isa::CallConv) -> Vec<Writable<Reg>> {
let mut caller_saved = Vec::new();
for i in 0..29 {
let x = writable_xreg(i);
if is_reg_clobbered_by_call(call_conv_of_callee, x.to_reg().to_real_reg().unwrap()) {
caller_saved.push(x);
fn get_regs_clobbered_by_call(call_conv_of_callee: isa::CallConv) -> PRegSet {
let mut clobbers = DEFAULT_AAPCS_CLOBBERS;
if call_conv_of_callee.extends_baldrdash() {
// Every X-register except for x16, x17, x18 is
// caller-saved (clobbered by a call).
for i in 19..=28 {
clobbers.add(xreg_preg(i));
}
clobbers.add(vreg_preg(31));
}
for i in 0..32 {
let v = writable_vreg(i);
if is_reg_clobbered_by_call(call_conv_of_callee, v.to_reg().to_real_reg().unwrap()) {
caller_saved.push(v);
}
}
caller_saved
clobbers
}
fn get_ext_mode(
@@ -1290,47 +1293,74 @@ fn get_regs_restored_in_epilogue(
(int_saves, vec_saves)
}
fn is_reg_clobbered_by_call(call_conv_of_callee: isa::CallConv, r: RealReg) -> bool {
if call_conv_of_callee.extends_baldrdash() {
match r.class() {
RegClass::Int => {
let enc = r.hw_enc() & 31;
if !BALDRDASH_JIT_CALLEE_SAVED_GPR[enc as usize] {
return true;
}
// Otherwise, fall through to preserve native's ABI caller-saved.
}
RegClass::Float => {
let enc = r.hw_enc() & 31;
if !BALDRDASH_JIT_CALLEE_SAVED_FPU[enc as usize] {
return true;
}
// Otherwise, fall through to preserve native's ABI caller-saved.
}
};
}
match r.class() {
RegClass::Int => {
// x0 - x17 inclusive are caller-saves.
r.hw_enc() <= 17
}
RegClass::Float => {
// v0 - v7 inclusive and v16 - v31 inclusive are caller-saves. The
// upper 64 bits of v8 - v15 inclusive are also caller-saves.
// However, because we cannot currently represent partial registers
// to regalloc.rs, we indicate here that every vector register is
// caller-save. Because this function is used at *callsites*,
// approximating in this direction (save more than necessary) is
// conservative and thus safe.
//
// Note that we set the 'not included in clobber set' flag in the
// regalloc.rs API when a call instruction's callee has the same ABI
// as the caller (the current function body); this is safe (anything
// clobbered by callee can be clobbered by caller as well) and
// avoids unnecessary saves of v8-v15 in the prologue even though we
// include them as defs here.
true
}
}
const fn default_aapcs_clobbers() -> PRegSet {
PRegSet::empty()
// x0 - x17 inclusive are caller-saves.
.with(xreg_preg(0))
.with(xreg_preg(1))
.with(xreg_preg(2))
.with(xreg_preg(3))
.with(xreg_preg(4))
.with(xreg_preg(5))
.with(xreg_preg(6))
.with(xreg_preg(7))
.with(xreg_preg(8))
.with(xreg_preg(9))
.with(xreg_preg(10))
.with(xreg_preg(11))
.with(xreg_preg(12))
.with(xreg_preg(13))
.with(xreg_preg(14))
.with(xreg_preg(15))
.with(xreg_preg(16))
.with(xreg_preg(17))
// v0 - v7 inclusive and v16 - v31 inclusive are
// caller-saves. The upper 64 bits of v8 - v15 inclusive are
// also caller-saves. However, because we cannot currently
// represent partial registers to regalloc2, we indicate here
// that every vector register is caller-save. Because this
// function is used at *callsites*, approximating in this
// direction (save more than necessary) is conservative and
// thus safe.
//
// Note that we exclude clobbers from a call instruction when
// a call instruction's callee has the same ABI as the caller
// (the current function body); this is safe (anything
// clobbered by callee can be clobbered by caller as well) and
// avoids unnecessary saves of v8-v15 in the prologue even
// though we include them as defs here.
.with(vreg_preg(0))
.with(vreg_preg(1))
.with(vreg_preg(2))
.with(vreg_preg(3))
.with(vreg_preg(4))
.with(vreg_preg(5))
.with(vreg_preg(6))
.with(vreg_preg(7))
.with(vreg_preg(8))
.with(vreg_preg(9))
.with(vreg_preg(10))
.with(vreg_preg(11))
.with(vreg_preg(12))
.with(vreg_preg(13))
.with(vreg_preg(14))
.with(vreg_preg(15))
.with(vreg_preg(16))
.with(vreg_preg(17))
.with(vreg_preg(18))
.with(vreg_preg(19))
.with(vreg_preg(20))
.with(vreg_preg(21))
.with(vreg_preg(22))
.with(vreg_preg(23))
.with(vreg_preg(24))
.with(vreg_preg(25))
.with(vreg_preg(26))
.with(vreg_preg(27))
.with(vreg_preg(28))
.with(vreg_preg(29))
.with(vreg_preg(30))
.with(vreg_preg(31))
}
const DEFAULT_AAPCS_CLOBBERS: PRegSet = default_aapcs_clobbers();