Object function to canonicalize tree::Tree code. More...

#include <canon.hh>

Public Member Functions
	Canon (bool trace_p=false)
	Build a canonizer.
tree::rStm	operator() (const tree::rStm &tree)
	Canonicalizing Eseq and Calls.

Private Member Functions
tree::rTree	canon (tree::rTree tree)
	The actual worker.
bool	commutes_with_all_eseq (const tree::rTree &a, tree::tree_list_type::iterator start, tree::tree_list_type::iterator end)
	Are there any ESEQ in [begin, end) such that a does not commute with its SEQ part? Iff there are, return FALSE.
tree::rStm	assemble_stm (const tree::rStm &s1, const tree::rStm &s2)
	Assemble statements s1 and s2 together.
tree::rExp	assemble_eseq (tree::rStm s, tree::rExp e)
	Assemble statement s and expression e together.
tree::rSeq	operator() (const tree::rSeq &seq)
	Canonicalize seq, in particular, bubble up the sub SEQ, and get rid of nops..
tree::rExp	operator() (const tree::rEseq &eseq)
	Canonicalize eseq.
bool	valid_call (const tree::rTree &tree, const tree::rTree &call)
	Is call a (LIR-)valid son of tree?
tree::rTree	canon_default (const tree::rTree &tree)
	Canonicalize tree: lift the ESEQ children higher.

Private Attributes
bool	trace_p_
	Report debugging information.

Detailed Description

Object function to canonicalize tree::Tree code.

Constructor & Destructor Documentation

canon::Canon::Canon ( bool trace_p = false )

Build a canonizer.

Member Function Documentation

tree::rExp canon::Canon::assemble_eseq	(	tree::rStm	s,
		tree::rExp	e
	)

private

Assemble statement s and expression e together.

References assemble_stm(), and tree::Eseq::stm_get().

Referenced by canon_default(), and operator()().

tree::rStm canon::Canon::assemble_stm	(	const tree::rStm &	s1,
		const tree::rStm &	s2
	)

private

Assemble statements s1 and s2 together.

References tree::Tree::children_get().

Referenced by assemble_eseq(), and canon_default().

tree::rTree canon::Canon::canon ( tree::rTree tree )

private

The actual worker.

References canon_default(), misc::decendl(), misc::decindent(), misc::iendl(), misc::incendl(), operator()(), and trace_p_.

Referenced by operator()().

tree::rTree canon::Canon::canon_default ( const tree::rTree & tree )

private

Canonicalize tree: lift the ESEQ children higher.

Canonicalize \a tree: lift the ESEQ children higher.

tree is not an ESEQ nor a SEQ. Pay attention to the case of CALL too.

The logic here is different from that of Appel. He suggest that when we find an eseq, we should move its statement backwards, and pay attention to the conflicts with expressions that don't commute with this statement, in which case you need to store the value of this expression in a temporary, and move this move.

This is probably very natural in a recursive implementation, but we are based on lists, and this is awkward.

The implementation below has a different viewpoint: for instance with "call(name f, e1, eseq(s1, e2))", we don't wait to study "eseq(s1, e2)" to realize that "e1" has to move: when we study "e1" we look whether it commutes with any eseq-statement (here "s1") that follow it, and if not, we immediately move it. As a consequence, when we reach an eseq-statement (again, "s1"), there is nothing magical to do: just move it.

References assemble_eseq(), assemble_stm(), precondition, and valid_call().

Referenced by canon().