[meta] Recipes and encodings descriptions for RiscV;
This commit is contained in:
Benjamin Bouvier
267
cranelift/codegen/meta/src/isa/riscv/recipes.rs
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267
cranelift/codegen/meta/src/isa/riscv/recipes.rs
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use std::collections::HashMap;
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use crate::cdsl::formats::FormatRegistry;
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use crate::cdsl::instructions::InstructionPredicate;
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use crate::cdsl::recipes::{EncodingRecipeBuilder, EncodingRecipeNumber, Recipes, Stack};
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use crate::cdsl::regs::IsaRegs;
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use crate::shared::Definitions as SharedDefinitions;
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/// An helper to create recipes and use them when defining the RISCV encodings.
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pub struct RecipeGroup<'formats> {
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/// Memoized format registry, to pass it to the builders.
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formats: &'formats FormatRegistry,
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/// The actualy list of recipes explicitly created in this file.
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pub recipes: Recipes,
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/// Provides fast lookup from a name to an encoding recipe.
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name_to_recipe: HashMap<String, EncodingRecipeNumber>,
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}
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impl<'formats> RecipeGroup<'formats> {
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fn new(formats: &'formats FormatRegistry) -> Self {
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Self {
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formats,
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recipes: Recipes::new(),
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name_to_recipe: HashMap::new(),
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}
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}
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fn push(&mut self, builder: EncodingRecipeBuilder) {
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assert!(
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self.name_to_recipe.get(&builder.name).is_none(),
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format!("riscv recipe '{}' created twice", builder.name)
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);
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let name = builder.name.clone();
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let number = self.recipes.push(builder.build(self.formats));
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self.name_to_recipe.insert(name, number);
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}
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pub fn by_name(&self, name: &str) -> EncodingRecipeNumber {
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let number = *self
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.name_to_recipe
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.get(name)
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.expect(&format!("unknown riscv recipe name {}", name));
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number
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}
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pub fn collect(self) -> Recipes {
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self.recipes
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}
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}
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pub fn define<'formats>(
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shared_defs: &'formats SharedDefinitions,
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regs: &IsaRegs,
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) -> RecipeGroup<'formats> {
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let formats = &shared_defs.format_registry;
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// Format shorthands.
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let f_binary = formats.by_name("Binary");
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let f_binary_imm = formats.by_name("BinaryImm");
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let f_branch = formats.by_name("Branch");
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let f_branch_icmp = formats.by_name("BranchIcmp");
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let f_call = formats.by_name("Call");
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let f_call_indirect = formats.by_name("CallIndirect");
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let f_int_compare = formats.by_name("IntCompare");
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let f_int_compare_imm = formats.by_name("IntCompareImm");
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let f_jump = formats.by_name("Jump");
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let f_multiary = formats.by_name("MultiAry");
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let f_regmove = formats.by_name("RegMove");
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let f_unary = formats.by_name("Unary");
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let f_unary_imm = formats.by_name("UnaryImm");
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// Register classes shorthands.
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let gpr = regs.class_by_name("GPR");
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// Definitions.
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let mut recipes = RecipeGroup::new(&shared_defs.format_registry);
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// R-type 32-bit instructions: These are mostly binary arithmetic instructions.
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// The encbits are `opcode[6:2] | (funct3 << 5) | (funct7 << 8)
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recipes.push(
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EncodingRecipeBuilder::new("R", f_binary, 4)
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.operands_in(vec![gpr, gpr])
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.operands_out(vec![gpr])
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.emit("put_r(bits, in_reg0, in_reg1, out_reg0, sink);"),
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);
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// R-type with an immediate shift amount instead of rs2.
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recipes.push(
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EncodingRecipeBuilder::new("Rshamt", f_binary_imm, 4)
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.operands_in(vec![gpr])
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.operands_out(vec![gpr])
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.emit("put_rshamt(bits, in_reg0, imm.into(), out_reg0, sink);"),
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);
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// R-type encoding of an integer comparison.
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recipes.push(
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EncodingRecipeBuilder::new("Ricmp", f_int_compare, 4)
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.operands_in(vec![gpr, gpr])
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.operands_out(vec![gpr])
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.emit("put_r(bits, in_reg0, in_reg1, out_reg0, sink);"),
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);
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let format = formats.get(f_binary_imm);
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recipes.push(
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EncodingRecipeBuilder::new("Ii", f_binary_imm, 4)
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.operands_in(vec![gpr])
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.operands_out(vec![gpr])
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.inst_predicate(InstructionPredicate::new_is_signed_int(
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format, "imm", 12, 0,
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))
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.emit("put_i(bits, in_reg0, imm.into(), out_reg0, sink);"),
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);
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// I-type instruction with a hardcoded %x0 rs1.
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let format = formats.get(f_unary_imm);
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recipes.push(
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EncodingRecipeBuilder::new("Iz", f_unary_imm, 4)
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.operands_out(vec![gpr])
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.inst_predicate(InstructionPredicate::new_is_signed_int(
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format, "imm", 12, 0,
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))
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.emit("put_i(bits, 0, imm.into(), out_reg0, sink);"),
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);
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// I-type encoding of an integer comparison.
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let format = formats.get(f_int_compare_imm);
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recipes.push(
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EncodingRecipeBuilder::new("Iicmp", f_int_compare_imm, 4)
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.operands_in(vec![gpr])
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.operands_out(vec![gpr])
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.inst_predicate(InstructionPredicate::new_is_signed_int(
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format, "imm", 12, 0,
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))
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.emit("put_i(bits, in_reg0, imm.into(), out_reg0, sink);"),
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);
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// I-type encoding for `jalr` as a return instruction. We won't use the immediate offset. The
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// variable return values are not encoded.
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recipes.push(EncodingRecipeBuilder::new("Iret", f_multiary, 4).emit(
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r#"
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// Return instructions are always a jalr to %x1.
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// The return address is provided as a special-purpose link argument.
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put_i(
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bits,
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1, // rs1 = %x1
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0, // no offset.
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0, // rd = %x0: no address written.
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sink,
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);
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"#,
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));
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// I-type encoding for `jalr` as a call_indirect.
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recipes.push(
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EncodingRecipeBuilder::new("Icall", f_call_indirect, 4)
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.operands_in(vec![gpr])
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.emit(
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r#"
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// call_indirect instructions are jalr with rd=%x1.
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put_i(
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bits,
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in_reg0,
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0, // no offset.
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1, // rd = %x1: link register.
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sink,
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);
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"#,
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),
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);
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// Copy of a GPR is implemented as addi x, 0.
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recipes.push(
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EncodingRecipeBuilder::new("Icopy", f_unary, 4)
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.operands_in(vec![gpr])
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.operands_out(vec![gpr])
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.emit("put_i(bits, in_reg0, 0, out_reg0, sink);"),
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);
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// Same for a GPR regmove.
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recipes.push(
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EncodingRecipeBuilder::new("Irmov", f_regmove, 4)
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.operands_in(vec![gpr])
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.emit("put_i(bits, src, 0, dst, sink);"),
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);
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// U-type instructions have a 20-bit immediate that targets bits 12-31.
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let format = formats.get(f_unary_imm);
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recipes.push(
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EncodingRecipeBuilder::new("U", f_unary_imm, 4)
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.operands_out(vec![gpr])
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.inst_predicate(InstructionPredicate::new_is_signed_int(
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format, "imm", 32, 12,
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))
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.emit("put_u(bits, imm.into(), out_reg0, sink);"),
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);
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// UJ-type unconditional branch instructions.
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recipes.push(
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EncodingRecipeBuilder::new("UJ", f_jump, 4)
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.branch_range((0, 21))
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.emit(
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r#"
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let dest = i64::from(func.offsets[destination]);
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let disp = dest - i64::from(sink.offset());
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put_uj(bits, disp, 0, sink);
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"#,
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),
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);
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recipes.push(EncodingRecipeBuilder::new("UJcall", f_call, 4).emit(
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r#"
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sink.reloc_external(Reloc::RiscvCall,
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&func.dfg.ext_funcs[func_ref].name,
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0);
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// rd=%x1 is the standard link register.
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put_uj(bits, 0, 1, sink);
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"#,
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));
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// SB-type branch instructions.
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recipes.push(
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EncodingRecipeBuilder::new("SB", f_branch_icmp, 4)
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.operands_in(vec![gpr, gpr])
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.branch_range((0, 13))
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.emit(
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r#"
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let dest = i64::from(func.offsets[destination]);
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let disp = dest - i64::from(sink.offset());
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put_sb(bits, disp, in_reg0, in_reg1, sink);
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"#,
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),
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);
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// SB-type branch instruction with rs2 fixed to zero.
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recipes.push(
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EncodingRecipeBuilder::new("SBzero", f_branch, 4)
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.operands_in(vec![gpr])
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.branch_range((0, 13))
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.emit(
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r#"
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let dest = i64::from(func.offsets[destination]);
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let disp = dest - i64::from(sink.offset());
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put_sb(bits, disp, in_reg0, 0, sink);
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"#,
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),
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);
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// Spill of a GPR.
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recipes.push(
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EncodingRecipeBuilder::new("GPsp", f_unary, 4)
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.operands_in(vec![gpr])
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.operands_out(vec![Stack::new(gpr)])
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.emit("unimplemented!();"),
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);
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// Fill of a GPR.
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recipes.push(
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EncodingRecipeBuilder::new("GPfi", f_unary, 4)
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.operands_in(vec![Stack::new(gpr)])
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.operands_out(vec![gpr])
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.emit("unimplemented!();"),
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);
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recipes
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}
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