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Interface BBlockSubtreeIterator

All Known Implementing Classes:

BBlockHirSubtreeIteratorImpl, BBlockStmtIterator, BBlockSubtreeIteratorImpl

public interface BBlockSubtreeIterator

BBlockSubtreeIterator traverses top-subtrees in the specified BBlock. IR tree should not be changed after instanciation of BBlockSubtreeIteratorImpl until all invocations of hasNext() and next() are finished. Traversed top-subtrees are LabeledStmt, AssignStmt, ExpStmt, ReturnStmt, IfStmt, LoopStmt, SwitchStmt Conditional expression in IfStmt and LoopStmt Case-selection expression in SwitchStmt Call subtree (irrespective of contained in ExpStmt or Exp)

Method Summary

boolean	hasNext() hasNext
IR	next() next Get the next top subtree in the basic block indicated by this iterator.

Method Detail

next

public IR next()

next Get the next top subtree in the basic block indicated by this iterator. If no one is left, return null. In HIR, statements other than LabeledStmt, AssignStmt, ExpStmt, ReturnStmt, IfStmt, LoopStmt, SwitchStmt //##65 are skipped because other statements does not set/refer data directly. (Other statements may set/refer data indirectly but such set/referes can be caught by above statements included in them. LabeledStmt is picked up to see BBlock boundary.) Expressions treated as top subtree in BBlockSubtreeIterator are conditional expressin in IfStmt, LoopStmt, case-selection expression in SwitchStmt, //##65 call-subtree in Exp. //##65 Conditional expression in IfStmt, LoopStmt The end of top subtree iteration should be checked not by null of next() but by hasNext() because there might be a case where the last top subtree is null (in such case as there remains a sequence of nodes but no top subtree is remaining).

hasNext

public boolean hasNext()

hasNext

Returns:

true if there remains thte next top subtree in the basic block.