Files
hakorune/archive/rust-llvm-backend/llvm/compiler/codegen/instructions/blocks.rs

114 lines
4.7 KiB
Rust

use inkwell::basic_block::BasicBlock;
use inkwell::values::{BasicValueEnum, FunctionValue, PhiValue};
use std::collections::HashMap;
use super::super::types::map_mirtype_to_basic;
use crate::backend::llvm::context::CodegenContext;
use crate::mir::{function::MirFunction, BasicBlockId, ValueId};
// Small, safe extraction: create LLVM basic blocks for a MIR function and
// return the block map together with the entry block.
pub(in super::super) fn create_basic_blocks<'ctx>(
codegen: &CodegenContext<'ctx>,
llvm_func: FunctionValue<'ctx>,
func: &MirFunction,
fn_label: &str,
) -> (HashMap<BasicBlockId, BasicBlock<'ctx>>, BasicBlock<'ctx>) {
let mut bb_map: HashMap<BasicBlockId, BasicBlock> = HashMap::new();
let entry_first = func.entry_block;
let entry_bb = codegen.context.append_basic_block(
llvm_func,
&format!("{}_bb{}", fn_label, entry_first.as_u32()),
);
bb_map.insert(entry_first, entry_bb);
for bid in func.block_ids() {
if bid == entry_first {
continue;
}
let name = format!("{}_bb{}", fn_label, bid.as_u32());
let bb = codegen.context.append_basic_block(llvm_func, &name);
bb_map.insert(bid, bb);
}
(bb_map, entry_bb)
}
// Pre-create PHI nodes for all blocks; also inserts placeholder values into vmap.
pub(in super::super) fn precreate_phis<'ctx>(
codegen: &CodegenContext<'ctx>,
func: &MirFunction,
bb_map: &HashMap<BasicBlockId, BasicBlock<'ctx>>,
vmap: &mut HashMap<ValueId, BasicValueEnum<'ctx>>,
) -> Result<
HashMap<BasicBlockId, Vec<(ValueId, PhiValue<'ctx>, Vec<(BasicBlockId, ValueId)>)>>,
String,
> {
use super::super::types::map_mirtype_to_basic;
let mut phis_by_block: HashMap<
BasicBlockId,
Vec<(ValueId, PhiValue<'ctx>, Vec<(BasicBlockId, ValueId)>)>,
> = HashMap::new();
for bid in func.block_ids() {
let bb = *bb_map.get(&bid).ok_or("missing bb in map")?;
codegen.builder.position_at_end(bb);
let block = func.blocks.get(&bid).unwrap();
for inst in block
.instructions
.iter()
.take_while(|i| matches!(i, crate::mir::instruction::MirInstruction::Phi { .. }))
{
if let crate::mir::instruction::MirInstruction::Phi { dst, inputs } = inst {
let mut phi_ty: Option<inkwell::types::BasicTypeEnum> = None;
// Prefer pointer when any input (or dst) is String/Box/Array/Future/Unknown
let mut wants_ptr = false;
if let Some(mt) = func.metadata.value_types.get(dst) {
wants_ptr |= matches!(
mt,
crate::mir::MirType::String
| crate::mir::MirType::Box(_)
| crate::mir::MirType::Array(_)
| crate::mir::MirType::Future(_)
| crate::mir::MirType::Unknown
);
}
for (_, iv) in inputs.iter() {
if let Some(mt) = func.metadata.value_types.get(iv) {
wants_ptr |= matches!(
mt,
crate::mir::MirType::String
| crate::mir::MirType::Box(_)
| crate::mir::MirType::Array(_)
| crate::mir::MirType::Future(_)
| crate::mir::MirType::Unknown
);
}
}
if wants_ptr {
phi_ty = Some(
codegen
.context
.ptr_type(inkwell::AddressSpace::from(0))
.into(),
);
} else if let Some(mt) = func.metadata.value_types.get(dst) {
phi_ty = Some(map_mirtype_to_basic(codegen.context, mt));
} else if let Some((_, iv)) = inputs.first() {
if let Some(mt) = func.metadata.value_types.get(iv) {
phi_ty = Some(map_mirtype_to_basic(codegen.context, mt));
}
}
let phi_ty = phi_ty.unwrap_or_else(|| codegen.context.i64_type().into());
let phi = codegen
.builder
.build_phi(phi_ty, &format!("phi_{}", dst.as_u32()))
.map_err(|e| e.to_string())?;
vmap.insert(*dst, phi.as_basic_value());
phis_by_block
.entry(bid)
.or_default()
.push((*dst, phi, inputs.clone()));
}
}
}
Ok(phis_by_block)
}