Class Sem::SsaPhiNode

A phi node in the SSA form. A phi node is a kind of node in the SSA form that represents a merge point where multiple control flow paths converge and the value of a variable needs to be selected according to which control flow path was taken. For example, in the following Ruby code:

if b
  x = 0
else
  x = 1
end
puts x

A phi node for x is inserted just before the call puts x, since the value of x may come from either x = 0 or x = 1.

Import path

import semmle.code.java.dataflow.RangeAnalysis

Direct supertypes

SsaVariable

Indirect supertypes

Predicates

hasInputFromBlock

Holds if inp is an input to the phi node along the edge originating in bb.

Inherited predicates

definesAt	Holds if this SSA definition defines `v` at index `i` in basic block `bb`. Phi nodes are considered to be at index `-1`, while normal variable writes are at the index of the control flow node they wrap.	from Definition
getAFirstUse	Gets an access of the SSA source variable underlying this SSA variable that can be reached from this SSA variable without passing through any other uses, but potentially through phi nodes and uncertain implicit updates.	from SsaVariable
getAPhiInputOrPriorDef	Gets an SSA variable whose value can flow to this one in one step. This includes inputs to phi nodes, the prior definition of uncertain updates, and the captured ssa variable for a closure variable.	from SsaVariable
getAUse	Gets an access of this SSA variable.	from SsaVariable
getAnUltimateDefinition	Gets a definition that ultimately defines this variable and is not itself a phi node.	from SsaVariable
getBasicBlock	Gets the `BasicBlock` in which this SSA variable is defined.	from SsaVariable
getCfgNode	Gets the `ControlFlowNode` at which this SSA variable is defined.	from SsaVariable
getLocation	Gets the source location for this element.	from SsaVariable
getSourceVariable	Gets the SSA source variable underlying this SSA variable.	from SsaVariable
isLiveAtEndOfBlock	Holds if this SSA variable is live at the end of `b`.	from SsaVariable
toString	Gets a textual representation of this SSA variable.	from SsaVariable