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Implement initial emission of constants

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This approach suffers from memory-size bloat during compile time due to the desire to de-duplicate the constants emitted and reduce runtime memory-size. As a first step, though, this provides an end-to-end mechanism for constants to be emitted in the MachBuffer islands.
This commit is contained in:
Andrew Brown
2020-10-27 11:54:15 -07:00
parent efa87d4c17
commit 83f182b390
7 changed files with 251 additions and 64 deletions
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24
cranelift/codegen/src/isa/x64/lower.rs
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@@ -3345,17 +3345,21 @@ fn lower_insn_to_regs<C: LowerCtx<I = Inst>>(
}
Opcode::Vconst => {
let val = if let &InstructionData::UnaryConst {
let used_constant = if let &InstructionData::UnaryConst {
constant_handle, ..
} = ctx.data(insn)
{
ctx.get_constant_data(constant_handle).clone().into_vec()
ctx.use_constant(VCodeConstantData::Pool(
constant_handle,
ctx.get_constant_data(constant_handle).clone(),
))
} else {
unreachable!("vconst should always have unary_const format")
};
// TODO use Inst::gen_constant() instead.
let dst = get_output_reg(ctx, outputs[0]);
let ty = ty.unwrap();
ctx.emit(Inst::xmm_load_const_seq(val, dst, ty));
ctx.emit(Inst::xmm_load_const(used_constant, dst, ty));
}
Opcode::RawBitcast => {
@@ -3396,8 +3400,9 @@ fn lower_insn_to_regs<C: LowerCtx<I = Inst>>(
.map(|&b| if b > 15 { b.wrapping_sub(16) } else { b })
.map(zero_unknown_lane_index)
.collect();
let constant = ctx.use_constant(VCodeConstantData::Generated(constructed_mask));
let tmp = ctx.alloc_tmp(RegClass::V128, types::I8X16);
ctx.emit(Inst::xmm_load_const_seq(constructed_mask, tmp, ty));
ctx.emit(Inst::xmm_load_const(constant, tmp, ty));
// After loading the constructed mask in a temporary register, we use this to
// shuffle the `dst` register (remember that, in this case, it is the same as
// `src` so we disregard this register).
@@ -3416,8 +3421,9 @@ fn lower_insn_to_regs<C: LowerCtx<I = Inst>>(
let tmp0 = ctx.alloc_tmp(RegClass::V128, lhs_ty);
ctx.emit(Inst::gen_move(tmp0, lhs, lhs_ty));
let constructed_mask = mask.iter().cloned().map(zero_unknown_lane_index).collect();
let constant = ctx.use_constant(VCodeConstantData::Generated(constructed_mask));
let tmp1 = ctx.alloc_tmp(RegClass::V128, types::I8X16);
ctx.emit(Inst::xmm_load_const_seq(constructed_mask, tmp1, ty));
ctx.emit(Inst::xmm_load_const(constant, tmp1, ty));
ctx.emit(Inst::xmm_rm_r(
SseOpcode::Pshufb,
RegMem::from(tmp1),
@@ -3431,8 +3437,9 @@ fn lower_insn_to_regs<C: LowerCtx<I = Inst>>(
.map(|b| b.wrapping_sub(16))
.map(zero_unknown_lane_index)
.collect();
let constant = ctx.use_constant(VCodeConstantData::Generated(constructed_mask));
let tmp2 = ctx.alloc_tmp(RegClass::V128, types::I8X16);
ctx.emit(Inst::xmm_load_const_seq(constructed_mask, tmp2, ty));
ctx.emit(Inst::xmm_load_const(constant, tmp2, ty));
ctx.emit(Inst::xmm_rm_r(
SseOpcode::Pshufb,
RegMem::from(tmp2),
@@ -3469,11 +3476,12 @@ fn lower_insn_to_regs<C: LowerCtx<I = Inst>>(
// Create a mask for zeroing out-of-bounds lanes of the swizzle mask.
let zero_mask = ctx.alloc_tmp(RegClass::V128, types::I8X16);
let zero_mask_value = vec![
static ZERO_MASK_VALUE: [u8; 16] = [
0x70, 0x70, 0x70, 0x70, 0x70, 0x70, 0x70, 0x70, 0x70, 0x70, 0x70, 0x70, 0x70, 0x70,
0x70, 0x70,
];
ctx.emit(Inst::xmm_load_const_seq(zero_mask_value, zero_mask, ty));
let constant = ctx.use_constant(VCodeConstantData::WellKnown(&ZERO_MASK_VALUE));
ctx.emit(Inst::xmm_load_const(constant, zero_mask, ty));
// Use the `zero_mask` on a writable `swizzle_mask`.
let swizzle_mask = Writable::from_reg(swizzle_mask);