Files
wasmtime/cranelift/codegen/meta/src/isa/riscv/recipes.rs

294 lines
10 KiB
Rust

use std::collections::HashMap;
use crate::cdsl::formats::FormatRegistry;
use crate::cdsl::instructions::InstructionPredicate;
use crate::cdsl::recipes::{EncodingRecipeBuilder, EncodingRecipeNumber, Recipes, Stack};
use crate::cdsl::regs::IsaRegs;
use crate::shared::Definitions as SharedDefinitions;
/// An helper to create recipes and use them when defining the RISCV encodings.
pub struct RecipeGroup<'formats> {
/// Memoized format registry, to pass it to the builders.
formats: &'formats FormatRegistry,
/// The actualy list of recipes explicitly created in this file.
pub recipes: Recipes,
/// Provides fast lookup from a name to an encoding recipe.
name_to_recipe: HashMap<String, EncodingRecipeNumber>,
}
impl<'formats> RecipeGroup<'formats> {
fn new(formats: &'formats FormatRegistry) -> Self {
Self {
formats,
recipes: Recipes::new(),
name_to_recipe: HashMap::new(),
}
}
fn push(&mut self, builder: EncodingRecipeBuilder) {
assert!(
self.name_to_recipe.get(&builder.name).is_none(),
format!("riscv recipe '{}' created twice", builder.name)
);
let name = builder.name.clone();
let number = self.recipes.push(builder.build(self.formats));
self.name_to_recipe.insert(name, number);
}
pub fn by_name(&self, name: &str) -> EncodingRecipeNumber {
let number = *self
.name_to_recipe
.get(name)
.expect(&format!("unknown riscv recipe name {}", name));
number
}
pub fn collect(self) -> Recipes {
self.recipes
}
}
pub(crate) fn define<'formats>(
shared_defs: &'formats SharedDefinitions,
regs: &IsaRegs,
) -> RecipeGroup<'formats> {
let formats = &shared_defs.format_registry;
// Format shorthands.
let f_binary = formats.by_name("Binary");
let f_binary_imm = formats.by_name("BinaryImm");
let f_branch = formats.by_name("Branch");
let f_branch_icmp = formats.by_name("BranchIcmp");
let f_call = formats.by_name("Call");
let f_call_indirect = formats.by_name("CallIndirect");
let f_copy_to_ssa = formats.by_name("CopyToSsa");
let f_int_compare = formats.by_name("IntCompare");
let f_int_compare_imm = formats.by_name("IntCompareImm");
let f_jump = formats.by_name("Jump");
let f_multiary = formats.by_name("MultiAry");
let f_regmove = formats.by_name("RegMove");
let f_unary = formats.by_name("Unary");
let f_unary_imm = formats.by_name("UnaryImm");
// Register classes shorthands.
let gpr = regs.class_by_name("GPR");
// Definitions.
let mut recipes = RecipeGroup::new(&shared_defs.format_registry);
// R-type 32-bit instructions: These are mostly binary arithmetic instructions.
// The encbits are `opcode[6:2] | (funct3 << 5) | (funct7 << 8)
recipes.push(
EncodingRecipeBuilder::new("R", f_binary, 4)
.operands_in(vec![gpr, gpr])
.operands_out(vec![gpr])
.emit("put_r(bits, in_reg0, in_reg1, out_reg0, sink);"),
);
// R-type with an immediate shift amount instead of rs2.
recipes.push(
EncodingRecipeBuilder::new("Rshamt", f_binary_imm, 4)
.operands_in(vec![gpr])
.operands_out(vec![gpr])
.emit("put_rshamt(bits, in_reg0, imm.into(), out_reg0, sink);"),
);
// R-type encoding of an integer comparison.
recipes.push(
EncodingRecipeBuilder::new("Ricmp", f_int_compare, 4)
.operands_in(vec![gpr, gpr])
.operands_out(vec![gpr])
.emit("put_r(bits, in_reg0, in_reg1, out_reg0, sink);"),
);
let format = formats.get(f_binary_imm);
recipes.push(
EncodingRecipeBuilder::new("Ii", f_binary_imm, 4)
.operands_in(vec![gpr])
.operands_out(vec![gpr])
.inst_predicate(InstructionPredicate::new_is_signed_int(
format, "imm", 12, 0,
))
.emit("put_i(bits, in_reg0, imm.into(), out_reg0, sink);"),
);
// I-type instruction with a hardcoded %x0 rs1.
let format = formats.get(f_unary_imm);
recipes.push(
EncodingRecipeBuilder::new("Iz", f_unary_imm, 4)
.operands_out(vec![gpr])
.inst_predicate(InstructionPredicate::new_is_signed_int(
format, "imm", 12, 0,
))
.emit("put_i(bits, 0, imm.into(), out_reg0, sink);"),
);
// I-type encoding of an integer comparison.
let format = formats.get(f_int_compare_imm);
recipes.push(
EncodingRecipeBuilder::new("Iicmp", f_int_compare_imm, 4)
.operands_in(vec![gpr])
.operands_out(vec![gpr])
.inst_predicate(InstructionPredicate::new_is_signed_int(
format, "imm", 12, 0,
))
.emit("put_i(bits, in_reg0, imm.into(), out_reg0, sink);"),
);
// I-type encoding for `jalr` as a return instruction. We won't use the immediate offset. The
// variable return values are not encoded.
recipes.push(EncodingRecipeBuilder::new("Iret", f_multiary, 4).emit(
r#"
// Return instructions are always a jalr to %x1.
// The return address is provided as a special-purpose link argument.
put_i(
bits,
1, // rs1 = %x1
0, // no offset.
0, // rd = %x0: no address written.
sink,
);
"#,
));
// I-type encoding for `jalr` as a call_indirect.
recipes.push(
EncodingRecipeBuilder::new("Icall", f_call_indirect, 4)
.operands_in(vec![gpr])
.emit(
r#"
// call_indirect instructions are jalr with rd=%x1.
put_i(
bits,
in_reg0,
0, // no offset.
1, // rd = %x1: link register.
sink,
);
"#,
),
);
// Copy of a GPR is implemented as addi x, 0.
recipes.push(
EncodingRecipeBuilder::new("Icopy", f_unary, 4)
.operands_in(vec![gpr])
.operands_out(vec![gpr])
.emit("put_i(bits, in_reg0, 0, out_reg0, sink);"),
);
// Same for a GPR regmove.
recipes.push(
EncodingRecipeBuilder::new("Irmov", f_regmove, 4)
.operands_in(vec![gpr])
.emit("put_i(bits, src, 0, dst, sink);"),
);
// Same for copy-to-SSA -- GPR regmove.
recipes.push(
EncodingRecipeBuilder::new("copytossa", f_copy_to_ssa, 4)
// No operands_in to mention, because a source register is specified directly.
.operands_out(vec![gpr])
.emit("put_i(bits, src, 0, out_reg0, sink);"),
);
// U-type instructions have a 20-bit immediate that targets bits 12-31.
let format = formats.get(f_unary_imm);
recipes.push(
EncodingRecipeBuilder::new("U", f_unary_imm, 4)
.operands_out(vec![gpr])
.inst_predicate(InstructionPredicate::new_is_signed_int(
format, "imm", 32, 12,
))
.emit("put_u(bits, imm.into(), out_reg0, sink);"),
);
// UJ-type unconditional branch instructions.
recipes.push(
EncodingRecipeBuilder::new("UJ", f_jump, 4)
.branch_range((0, 21))
.emit(
r#"
let dest = i64::from(func.offsets[destination]);
let disp = dest - i64::from(sink.offset());
put_uj(bits, disp, 0, sink);
"#,
),
);
recipes.push(EncodingRecipeBuilder::new("UJcall", f_call, 4).emit(
r#"
sink.reloc_external(Reloc::RiscvCall,
&func.dfg.ext_funcs[func_ref].name,
0);
// rd=%x1 is the standard link register.
put_uj(bits, 0, 1, sink);
"#,
));
// SB-type branch instructions.
recipes.push(
EncodingRecipeBuilder::new("SB", f_branch_icmp, 4)
.operands_in(vec![gpr, gpr])
.branch_range((0, 13))
.emit(
r#"
let dest = i64::from(func.offsets[destination]);
let disp = dest - i64::from(sink.offset());
put_sb(bits, disp, in_reg0, in_reg1, sink);
"#,
),
);
// SB-type branch instruction with rs2 fixed to zero.
recipes.push(
EncodingRecipeBuilder::new("SBzero", f_branch, 4)
.operands_in(vec![gpr])
.branch_range((0, 13))
.emit(
r#"
let dest = i64::from(func.offsets[destination]);
let disp = dest - i64::from(sink.offset());
put_sb(bits, disp, in_reg0, 0, sink);
"#,
),
);
// Spill of a GPR.
recipes.push(
EncodingRecipeBuilder::new("GPsp", f_unary, 4)
.operands_in(vec![gpr])
.operands_out(vec![Stack::new(gpr)])
.emit("unimplemented!();"),
);
// Fill of a GPR.
recipes.push(
EncodingRecipeBuilder::new("GPfi", f_unary, 4)
.operands_in(vec![Stack::new(gpr)])
.operands_out(vec![gpr])
.emit("unimplemented!();"),
);
// Stack-slot to same stack-slot copy, which is guaranteed to turn into a no-op.
recipes.push(
EncodingRecipeBuilder::new("stacknull", f_unary, 0)
.operands_in(vec![Stack::new(gpr)])
.operands_out(vec![Stack::new(gpr)])
.emit(""),
);
// No-op fills, created by late-stage redundant-fill removal.
recipes.push(
EncodingRecipeBuilder::new("fillnull", f_unary, 0)
.operands_in(vec![Stack::new(gpr)])
.operands_out(vec![gpr])
.clobbers_flags(false)
.emit(""),
);
recipes
}