Class EachElementGetInstruction


public class EachElementGetInstruction extends SSAAbstractBinaryInstruction
This instruction represents iterating through the properties of its receiver object. The use represents an object, and the l-value represents one of a sequence of property names, suitable for use with the appropriate AbstractReflectiveGet sub-class.

Iterating across the fields or properties of a given object is a common idiom in scripting languages, which is why the IR has first-class support for it.

Author:
Julian Dolby (dolby@us.ibm.com)
  • Constructor Details

    • EachElementGetInstruction

      public EachElementGetInstruction(int iindex, int lValue, int objectRef, int previousProp)
  • Method Details

    • copyForSSA

      public SSAInstruction copyForSSA(SSAInstructionFactory insts, int[] defs, int[] uses)
      Description copied from class: SSAInstruction
      This 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:
      copyForSSA in class SSAInstruction
    • toString

      public String toString(SymbolTable symbolTable)
      Specified by:
      toString in class SSAInstruction
    • visit

      public void visit(SSAInstruction.IVisitor v)
      Description copied from class: SSAInstruction
      Apply an IVisitor to this instruction. We invoke the appropriate IVisitor method according to the type of this instruction.
      Specified by:
      visit in class SSAInstruction
    • getExceptionTypes

      public Collection<TypeReference> getExceptionTypes()
      Description copied from class: SSAInstruction
      This method should never return null.
      Overrides:
      getExceptionTypes in class SSAInstruction
      Returns:
      the set of exception types that an instruction might throw ... disregarding athrows and invokes.
    • isFallThrough

      public boolean isFallThrough()
      Specified by:
      isFallThrough in class SSAInstruction
      Returns:
      true iff this instruction may fall through to the next
    • isPEI

      public boolean isPEI()
      Overrides:
      isPEI in class SSAInstruction
      Returns:
      true iff this instruction may throw an exception.