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Merge pull request #2363 from cfallin/extend-only-if-abi

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Do value-extensions at ABI boundaries only when ABI requires it.
This commit is contained in:
Chris Fallin
2020-11-12 12:26:20 -08:00
committed by GitHub
parent fd6433aaf5 a2bbb198de
commit 89dbc4590d
7 changed files with 98 additions and 47 deletions
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51
cranelift/codegen/src/machinst/abi_impl.rs
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@@ -369,6 +369,16 @@ pub trait ABIMachineSpec {
/// Get all caller-save registers, that is, registers that we expect
/// not to be saved across a call to a callee with the given ABI.
fn get_regs_clobbered_by_call(call_conv_of_callee: isa::CallConv) -> Vec<Writable<Reg>>;
/// Get the needed extension mode, given the mode attached to the argument
/// in the signature and the calling convention. The input (the attribute in
/// the signature) specifies what extension type should be done *if* the ABI
/// requires extension to the full register; this method's return value
/// indicates whether the extension actually *will* be done.
fn get_ext_mode(
call_conv: isa::CallConv,
specified: ir::ArgumentExtension,
) -> ir::ArgumentExtension;
}
/// ABI information shared between body (callee) and caller.
@@ -770,6 +780,7 @@ impl<M: ABIMachineSpec> ABICallee for ABICalleeImpl<M> {
&ABIArg::Reg(r, ty, ext, ..) => {
let from_bits = ty_bits(ty) as u8;
let dest_reg = Writable::from_reg(r.to_reg());
let ext = M::get_ext_mode(self.sig.call_conv, ext);
match (ext, from_bits) {
(ArgumentExtension::Uext, n) | (ArgumentExtension::Sext, n)
if n < word_bits =>
@@ -793,6 +804,7 @@ impl<M: ABIMachineSpec> ABICallee for ABICalleeImpl<M> {
// backends (aarch64 and x64) enforce a 128MB limit.
let off = i32::try_from(off)
.expect("Argument stack offset greater than 2GB; should hit impl limit first");
let ext = M::get_ext_mode(self.sig.call_conv, ext);
// Trash the from_reg; it should be its last use.
match (ext, from_bits) {
(ArgumentExtension::Uext, n) | (ArgumentExtension::Sext, n)
@@ -1211,27 +1223,28 @@ impl<M: ABIMachineSpec> ABICaller for ABICallerImpl<M> {
let word_rc = M::word_reg_class();
let word_bits = M::word_bits() as usize;
match &self.sig.args[idx] {
&ABIArg::Reg(reg, ty, ext, _)
if ext != ir::ArgumentExtension::None && ty_bits(ty) < word_bits =>
{
assert_eq!(word_rc, reg.get_class());
let signed = match ext {
ir::ArgumentExtension::Uext => false,
ir::ArgumentExtension::Sext => true,
_ => unreachable!(),
};
ctx.emit(M::gen_extend(
Writable::from_reg(reg.to_reg()),
from_reg,
signed,
ty_bits(ty) as u8,
word_bits as u8,
));
}
&ABIArg::Reg(reg, ty, _, _) => {
ctx.emit(M::gen_move(Writable::from_reg(reg.to_reg()), from_reg, ty));
&ABIArg::Reg(reg, ty, ext, _) => {
let ext = M::get_ext_mode(self.sig.call_conv, ext);
if ext != ir::ArgumentExtension::None && ty_bits(ty) < word_bits {
assert_eq!(word_rc, reg.get_class());
let signed = match ext {
ir::ArgumentExtension::Uext => false,
ir::ArgumentExtension::Sext => true,
_ => unreachable!(),
};
ctx.emit(M::gen_extend(
Writable::from_reg(reg.to_reg()),
from_reg,
signed,
ty_bits(ty) as u8,
word_bits as u8,
));
} else {
ctx.emit(M::gen_move(Writable::from_reg(reg.to_reg()), from_reg, ty));
}
}
&ABIArg::Stack(off, mut ty, ext, _) => {
let ext = M::get_ext_mode(self.sig.call_conv, ext);
if ext != ir::ArgumentExtension::None && ty_bits(ty) < word_bits {
assert_eq!(word_rc, from_reg.get_class());
let signed = match ext {