Problem: function copy don't work

[yihuang]

What I did

Fix IRFunction copy method to preserve necessary fields.

How I did it

How to verify it

Commit message

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Description for the changelog

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[Copilot]

Pull request overview

This PR updates Venom IR function cloning to make IRFunction.copy() produce a more usable duplicate of a function’s basic blocks, addressing the reported issue that “function copy don’t work”.

Changes:

• Clear the auto-created entry block when cloning, then rebuild the function from copied basic blocks.
• Preserve last_variable across copies to keep variable numbering consistent.
• Fix basic-block parent linkage (new_bb.parent = new) in the cloned function.

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[Copilot]

IRFunction.copy() currently copies last_variable and basic blocks, but it doesn't copy other function-level metadata like _invoke_param_count / _has_memory_return_buffer_param. These fields influence invoke-related optimizations/analyses; dropping them on copy can change behavior compared to the original function. If the intent is a faithful clone, copy these fields as well (or document/reset them explicitly if not).

Suggested change

	new.last_variable = self.last_variable
	new.last_variable = self.last_variable
	new._invoke_param_count = self._invoke_param_count
	new._has_memory_return_buffer_param = self._has_memory_return_buffer_param

[Copilot]

Creating an IRFunction and immediately calling clear_basic_blocks() works, but it relies on the constructor always auto-inserting an entry block (which then becomes an unused orphan). Consider a dedicated constructor arg / classmethod for creating an empty IRFunction (used here and in FunctionInlinerPass._clone_function) to make cloning less error-prone and avoid creating throwaway blocks.

[Copilot]

This change is fixing core cloning behavior (variable counter + basic-block/function parent linkage). There are many Venom unit tests, but none appear to cover IRFunction.copy() specifically; adding a regression test that exercises copy() (and then runs at least one analysis/pass on the copy, or appends an instruction and checks variable naming) would help prevent this from breaking again.

Suggested change

	new.last_variable = self.last_variable
	for bb in self.get_basic_blocks():
	new_bb = bb.copy()
	new_bb.parent = new
	new.append_basic_block(new_bb)
	new.last_variable = self.last_variable
	bb_map = {}
	copied_bbs = []
	for bb in self.get_basic_blocks():
	new_bb = bb.copy()
	new_bb.parent = new
	new.append_basic_block(new_bb)
	bb_map[bb] = new_bb
	copied_bbs.append((bb, new_bb))
	for old_bb, new_bb in copied_bbs:
	if hasattr(new_bb, "out_bbs") and hasattr(old_bb, "out_bbs"):
	new_bb.out_bbs = type(new_bb.out_bbs)(
	bb_map.get(out_bb, out_bb) for out_bb in old_bb.out_bbs
	)
	if hasattr(new_bb, "in_bbs") and hasattr(old_bb, "in_bbs"):
	new_bb.in_bbs = type(new_bb.in_bbs)(
	bb_map.get(in_bb, in_bb) for in_bb in old_bb.in_bbs
	)
	new_bb.parent = new

[Copilot]

IRFunction.copy() creates new = IRFunction(self.name) with no ctx, so new.ctx is None. Many analyses/passes assume fn.ctx exists (e.g. IRAnalysesCache._ensure_global_analyses_cache() dereferences self.function.ctx), so a copied function will crash if analyzed unless the caller manually reattaches a context. Consider constructing the copy with ctx=self.ctx (or explicitly setting new.ctx = self.ctx) so the copy is usable with the existing analysis/pass infrastructure.

Suggested change

	new = IRFunction(self.name)
	new = IRFunction(self.name, ctx=self.ctx)

[harkal]

This method is essentially dead code. We should probably remove it all-together.

[yihuang]

This method is essentially dead code. We should probably remove it all-together.

we are experimenting with the API to build EVM bytecodes programmatically, we are not sure if it's the right approach yet, so no strong opinions on this.