def insert_ref_count_opcodes(ir: FuncIR) -> None:
"""Insert reference count inc/dec opcodes to a function.
This is the entry point to this module.
"""
cfg = get_cfg(ir.blocks)
borrowed = set(reg for reg in ir.env.regs() if reg.is_borrowed)
args = set(reg for reg in ir.env.regs()
if ir.env.indexes[reg] < len(ir.args))
regs = [reg for reg in ir.env.regs() if isinstance(reg, Register)]
live = analyze_live_regs(ir.blocks, cfg)
borrow = analyze_borrowed_arguments(ir.blocks, cfg, borrowed)
defined = analyze_must_defined_regs(ir.blocks, cfg, args, regs)
cache = {} # type: BlockCache
for block in ir.blocks[:]:
if isinstance(block.ops[-1], (Branch, Goto)):
insert_branch_inc_and_decrefs(block, cache, ir.blocks, live.before,
borrow.before, borrow.after,
defined.after, ir.env)
transform_block(block, live.before, live.after, borrow.before,
defined.after, ir.env)
# Find all the xdecs we inserted and note the registers down as
# needing to be initialized.
for block in ir.blocks:
for op in block.ops:
if isinstance(op, DecRef) and op.is_xdec:
ir.env.vars_needing_init.add(op.src)
cleanup_cfg(ir.blocks)
def insert_uninit_checks(ir: FuncIR) -> None:
# Remove dead blocks from the CFG, which helps avoid spurious
# checks due to unused error handling blocks.
cleanup_cfg(ir.blocks)
cfg = get_cfg(ir.blocks)
args = set(reg for reg in ir.env.regs() if ir.env.indexes[reg] < len(ir.args))
must_defined = analyze_must_defined_regs(ir.blocks, cfg, args, ir.env.regs())
ir.blocks = split_blocks_at_uninits(ir.env, ir.blocks, must_defined.before)