Package com.ibm.wala.ssa
Class SSAPhiInstruction
- java.lang.Object
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- com.ibm.wala.ssa.SSAInstruction
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- com.ibm.wala.ssa.SSAPhiInstruction
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public class SSAPhiInstruction extends SSAInstruction
A phi instruction in SSA form. See any modern compiler textbook for the definition of phi and the nature of SSA. Note: In SSAIRs, these instructions do not appear in the normal instruction array returned by IR.getInstructions(); instead these instructions live inISSABasicBlock.getUse(i)corresponds to the value number from the ith predecessor of the correspondingISSABasicBlockbinControlFlowGraphg, where predecessor order is the order of nodes returned by theIteratorg.getPredNodes(b). Note: if getUse(i) returnsAbstractIntStackMachine.TOP (that is, -1), then that use represents an edge in the CFG which is infeasible in verifiable bytecode.
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Nested Class Summary
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Nested classes/interfaces inherited from class com.ibm.wala.ssa.SSAInstruction
SSAInstruction.IVisitor, SSAInstruction.Visitor
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Field Summary
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Fields inherited from class com.ibm.wala.ssa.SSAInstruction
iindex, NO_INDEX
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Constructor Summary
Constructors Constructor Description SSAPhiInstruction(int iindex, int result, int[] params)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description SSAInstructioncopyForSSA(SSAInstructionFactory insts, int[] defs, int[] uses)This method is meant to be used during SSA conversion for an IR that is not in SSA form.intgetDef()intgetDef(int i)Return the ith defintgetNumberOfDefs()intgetNumberOfUses()intgetUse(int j)protected StringgetValueString(SymbolTable symbolTable, int valueNumber)booleanhasDef()Does this instruction define a normal value, as distinct from a set of exceptions possibly thrown by it (e.g.inthashCode()booleanisFallThrough()voidsetValues(int[] i)Clients should not call this.StringtoString(SymbolTable symbolTable)voidvisit(SSAInstruction.IVisitor v)Apply an IVisitor to this instruction.-
Methods inherited from class com.ibm.wala.ssa.SSAInstruction
equals, getExceptionTypes, isPEI, toString
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Constructor Detail
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SSAPhiInstruction
public SSAPhiInstruction(int iindex, int result, int[] params) throws IllegalArgumentException- Throws:
IllegalArgumentException
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Method Detail
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copyForSSA
public SSAInstruction copyForSSA(SSAInstructionFactory insts, int[] defs, int[] uses) throws IllegalArgumentException
Description copied from class:SSAInstructionThis method is meant to be used during SSA conversion for an IR that is not in SSA form. It creates a new SSAInstruction of the same type as the receiver, with a combination of the receiver's uses and defs and those from the method parameters. In particular, if the 'defs' parameter is null, then the new instruction has the same defs as the receiver. If 'defs' is not null, it must be an array with a size equal to the number of defs that the receiver instruction has. In this case, the new instruction has defs taken from the array. The uses of the new instruction work in the same way with the 'uses' parameter. Note that this only applies to CAst-based IR translation, since Java bytecode-based IR generation uses a different SSA construction mechanism. TODO: move this into the SSAInstructionFactory- Specified by:
copyForSSAin classSSAInstruction- Throws:
IllegalArgumentException
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toString
public String toString(SymbolTable symbolTable)
- Specified by:
toStringin classSSAInstruction
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visit
public void visit(SSAInstruction.IVisitor v)
Description copied from class:SSAInstructionApply an IVisitor to this instruction. We invoke the appropriate IVisitor method according to the type of this instruction.- Specified by:
visitin classSSAInstruction- Throws:
IllegalArgumentException- if v is null- See Also:
SSAInstruction.visit(IVisitor)
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hasDef
public boolean hasDef()
Description copied from class:SSAInstructionDoes this instruction define a normal value, as distinct from a set of exceptions possibly thrown by it (e.g. for invoke instructions).- Overrides:
hasDefin classSSAInstruction- Returns:
- true if the instruction does define a proper value.
- See Also:
SSAInstruction.getDef()
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getDef
public int getDef()
- Overrides:
getDefin classSSAInstruction
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getDef
public int getDef(int i)
Description copied from class:SSAInstructionReturn the ith def- Overrides:
getDefin classSSAInstruction- Parameters:
i- number of the def, starting at 0.
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getNumberOfUses
public int getNumberOfUses()
- Overrides:
getNumberOfUsesin classSSAInstruction- See Also:
SSAInstruction.getNumberOfUses()
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getNumberOfDefs
public int getNumberOfDefs()
- Overrides:
getNumberOfDefsin classSSAInstruction
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getUse
public int getUse(int j) throws IllegalArgumentException- Overrides:
getUsein classSSAInstruction- Returns:
- value number representing the jth use in this instruction. -1 means TOP (i.e., the value doesn't matter)
- Throws:
IllegalArgumentException- See Also:
SSAInstruction.getUse(int)
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setValues
public void setValues(int[] i)
Clients should not call this. only for SSA builders. I hate this. Nuke it someday.
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getValueString
protected String getValueString(SymbolTable symbolTable, int valueNumber)
- Overrides:
getValueStringin classSSAInstruction- See Also:
com.ibm.wala.ssa.SSAInstruction#getValueString(SymbolTable, ValueDecorator, int)
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hashCode
public int hashCode()
- Specified by:
hashCodein classSSAInstruction
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isFallThrough
public boolean isFallThrough()
- Specified by:
isFallThroughin classSSAInstruction- Returns:
- true iff this instruction may fall through to the next
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