114 lines
3.7 KiB
Python
114 lines
3.7 KiB
Python
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"""
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PHI instruction lowering
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Critical for SSA form - handles value merging from different control flow paths
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"""
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import llvmlite.ir as ir
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from typing import Dict, List, Tuple, Optional
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def lower_phi(
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builder: ir.IRBuilder,
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dst_vid: int,
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incoming: List[Tuple[int, int]], # [(value_id, block_id), ...]
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vmap: Dict[int, ir.Value],
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bb_map: Dict[int, ir.Block],
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current_block: ir.Block,
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resolver=None # Resolver instance (optional)
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) -> None:
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"""
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Lower MIR PHI instruction
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Args:
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builder: Current LLVM IR builder
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dst_vid: Destination value ID
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incoming: List of (value_id, block_id) pairs
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vmap: Value map
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bb_map: Block map
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current_block: Current basic block
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resolver: Optional resolver for advanced type handling
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"""
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if not incoming:
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# No incoming edges - use zero
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vmap[dst_vid] = ir.Constant(ir.IntType(64), 0)
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return
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# Determine PHI type from first incoming value
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first_val_id = incoming[0][0]
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first_val = vmap.get(first_val_id)
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if first_val and hasattr(first_val, 'type'):
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phi_type = first_val.type
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else:
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# Default to i64
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phi_type = ir.IntType(64)
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# Create PHI instruction
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phi = builder.phi(phi_type, name=f"phi_{dst_vid}")
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# Add incoming values
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for val_id, block_id in incoming:
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val = vmap.get(val_id)
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block = bb_map.get(block_id)
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if not val:
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# Create default value based on type
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if isinstance(phi_type, ir.IntType):
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val = ir.Constant(phi_type, 0)
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elif isinstance(phi_type, ir.DoubleType):
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val = ir.Constant(phi_type, 0.0)
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else:
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# Pointer type - null
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val = ir.Constant(phi_type, None)
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if not block:
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# Skip if block not found
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continue
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# Type conversion if needed
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if hasattr(val, 'type') and val.type != phi_type:
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# Save current position
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saved_block = builder.block
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saved_pos = None
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if hasattr(builder, '_anchor'):
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saved_pos = builder._anchor
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# Position at end of predecessor block
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builder.position_at_end(block)
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# Convert types
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if isinstance(phi_type, ir.IntType) and val.type.is_pointer:
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val = builder.ptrtoint(val, phi_type, name=f"cast_p2i_{val_id}")
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elif phi_type.is_pointer and isinstance(val.type, ir.IntType):
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val = builder.inttoptr(val, phi_type, name=f"cast_i2p_{val_id}")
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elif isinstance(phi_type, ir.IntType) and isinstance(val.type, ir.IntType):
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# Int to int
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if phi_type.width > val.type.width:
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val = builder.zext(val, phi_type, name=f"zext_{val_id}")
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else:
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val = builder.trunc(val, phi_type, name=f"trunc_{val_id}")
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# Restore position
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builder.position_at_end(saved_block)
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if saved_pos and hasattr(builder, '_anchor'):
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builder._anchor = saved_pos
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# Add to PHI
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phi.add_incoming(val, block)
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# Store PHI result
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vmap[dst_vid] = phi
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def defer_phi_wiring(
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dst_vid: int,
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incoming: List[Tuple[int, int]],
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phi_deferrals: List[Tuple[int, List[Tuple[int, int]]]]
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) -> None:
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"""
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Defer PHI wiring for sealed block approach
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Args:
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dst_vid: Destination value ID
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incoming: Incoming edges
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phi_deferrals: List to store deferred PHIs
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"""
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phi_deferrals.append((dst_vid, incoming))
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