Package com.ibm.wala.ssa

Class IR

java.lang.Object
com.ibm.wala.ssa.IR
All Implemented Interfaces:
IRView
Direct Known Subclasses:
AstIRFactory.AstIR, SyntheticIR
public abstract class IR extends Object implements IRView
An SSA IR.

The IR (Intermediate Representation) is the central data structure that represents the instructions of a particular method. The IR represents a method's instructions in a language close to JVM bytecode, but in an SSA-based register transfer language which eliminates the stack abstraction, relying instead on a set of symbolic registers. The IR organizes instructions in a control-flow graph of basic blocks, as typical in compiler textbooks.

See more details on the IR API.

  • Constructor Details

  • Method Details

    • getLocalMap

      protected abstract IR.SSA2LocalMap getLocalMap()
      subclasses must provide a source name mapping, if they want one (or null otherwise)

    • getIndirectionData

      protected abstract <T extends SSAIndirectionData.Name> SSAIndirectionData<T> getIndirectionData()
      subclasses must provide information about indirect use of values, if appropriate, and otherwise null

    • setupLocationMap

      protected void setupLocationMap()
      create mappings from call sites, new sites, and PEIs to instruction index

    • instructionPosition

      protected abstract String instructionPosition(int instructionIndex)
      Returns:
      a String which is a readable representation of the instruction position corresponding to an instruction index

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • getInstructions

      public SSAInstruction[] getInstructions()
      Returns the normal instructions. Does not include SSAPhiInstruction, SSAPiInstruction, or SSAGetCaughtExceptionInstructions, which are currently managed by SSACFG.BasicBlock. Entries in the returned array might be null.

      This may go away someday.

      Specified by:
      getInstructions in interface IRView

    • getSymbolTable

      public SymbolTable getSymbolTable()
      Specified by:
      getSymbolTable in interface IRView
      Returns:
      the SymbolTable managing attributes for values in this method

    • getControlFlowGraph

      public SSACFG getControlFlowGraph()
      Specified by:
      getControlFlowGraph in interface IRView
      Returns:
      the underlying ControlFlowGraph which defines this IR.

    • getBlocks

      public Iterator<ISSABasicBlock> getBlocks()
      Specified by:
      getBlocks in interface IRView

    • iteratePhis

      public Iterator<? extends SSAInstruction> iteratePhis()
      Return an Iterator of all SSAPhiInstructions for this IR.

    • iteratePis

      public Iterator<? extends SSAInstruction> iteratePis()
      Return an Iterator of all SSAPiInstructions for this IR.

    • getParameterValueNumbers

      public int[] getParameterValueNumbers()
      Returns:
      array of value numbers representing parameters to this method

    • getParameter

      public int getParameter(int i)
      Returns:
      the value number of the ith parameter

    • getParameterType

      public TypeReference getParameterType(int i)
      Get the TypeReference that describes the ith parameter to this method. By convention, for a non-static method, the 0th parameter is "this".

    • getNumberOfParameters

      public int getNumberOfParameters()
      Returns:
      number of parameters to this method, including "this"

    • getMethod

      public IMethod getMethod()
      Specified by:
      getMethod in interface IRView
      Returns:
      the method this IR represents

    • iterateCatchInstructions

      public Iterator<SSAInstruction> iterateCatchInstructions()
      Returns:
      iterator of the catch instructions in this IR

    • visitNormalInstructions

      public void visitNormalInstructions(SSAInstruction.IVisitor v)
      visit each normal (non-phi, non-pi, non-catch) instruction in this IR

    • visitAllInstructions

      public void visitAllInstructions(SSAInstruction.IVisitor v)
      visit each instruction in this IR

    • iterateNormalInstructions

      public Iterator<SSAInstruction> iterateNormalInstructions()
      Returns:
      an Iterator of all "normal" instructions on this IR

    • iterateAllInstructions

      public Iterator<SSAInstruction> iterateAllInstructions()
      Returns:
      an Iterator of all instructions (Normal, Phi, and Catch)

    • getExitBlock

      public SSACFG.BasicBlock getExitBlock()
      Specified by:
      getExitBlock in interface IRView
      Returns:
      the exit basic block

    • getCalls

      public SSAAbstractInvokeInstruction[] getCalls(CallSiteReference site)
      Return the invoke instructions corresponding to a call site

      Note that Shrike may inline JSRS. This can lead to multiple copies of a single bytecode instruction in a particular IR. So we may have more than one instruction index for a particular call site from bytecode.

    • getCallInstructionIndices

      public IntSet getCallInstructionIndices(CallSiteReference site)
      Return the instruction indices corresponding to a call site.

      Note that Shrike may inline JSRS. This can lead to multiple copies of a single bytecode instruction in a particular IR. So we may have more than one instruction index for a particular call site from bytecode.

    • getNew

      public SSANewInstruction getNew(NewSiteReference site)
      Return the new instruction corresponding to an allocation site

    • getNewInstructionIndex

      public int getNewInstructionIndex(NewSiteReference site)
      Return the instruction index corresponding to an allocation site

    • getPEI

      public SSAInstruction getPEI(ProgramCounter pc)
      Specified by:
      getPEI in interface IRView
      Parameters:
      pc - a program counter
      Returns:
      the instruction (a PEI) at this program counter

    • iterateNewSites

      public Iterator<NewSiteReference> iterateNewSites()
      Specified by:
      iterateNewSites in interface IRView
      Returns:
      an Iterator of all the allocation sites ( NewSiteReferences ) in this IR

    • iterateCallSites

      public Iterator<CallSiteReference> iterateCallSites()
      Specified by:
      iterateCallSites in interface IRView
      Returns:
      an Iterator of all the call sites ( CallSiteReferences ) in this IR

    • getBasicBlocksForCall

      public ISSABasicBlock[] getBasicBlocksForCall(CallSiteReference site)
      Specified by:
      getBasicBlocksForCall in interface IRView
      Parameters:
      site - a call site in this method
      Returns:
      the basic block corresponding to this instruction
      Throws:
      IllegalArgumentException - if site is null

    • getBasicBlockForInstruction

      public ISSABasicBlock getBasicBlockForInstruction(SSAInstruction s)
      This is space-inefficient. Use with care.

      Be very careful; note the strange identity semantics of SSAInstruction, using ==. You can't mix SSAInstructions and IRs freely.

    • isEmptyIR

      public boolean isEmptyIR()
      TODO: why do we need this? We should enforce instructions == null if necessary, I think.
      Returns:
      true iff every instruction is null

    • getLocalNames

      public String[] getLocalNames(int index, int vn)
      Specified by:
      getLocalNames in interface IRView
      Parameters:
      index - an index into the IR instruction array
      vn - a value number
      Returns:
      if we know that immediately after the given program counter, v_vn corresponds to one or more locals and local variable names are available, the name of the locals which v_vn represents. Otherwise, null.

    • getBasicBlockForCatch

      public ISSABasicBlock getBasicBlockForCatch(SSAGetCaughtExceptionInstruction instruction)
      Return the ISSABasicBlock corresponding to a particular catch instruction

    • getOptions

      public SSAOptions getOptions()
      Returns:
      the SSAOptions which controlled how this IR was built