scala.tools.nsc.Global

# analysis

###
Related Doc: package Global

#### object analysis extends TypeFlowAnalysis

ICode analysis for optimization

Source
  Global.scala

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### Type Members

1. #### case class CallsiteInfo(bb: Global.icodes.BasicBlock, receiver: Global.Symbol, stackLength: Int, concreteMethod: Global.Symbol) extends Product with Serializable

   Definition Classes
     TypeFlowAnalysis

2. #### class MTFAGrowable extends MethodTFA

   A full type-flow analysis on a method computes in- and out-flows for each basic block (that's what MethodTFA does).

   A full type-flow analysis on a method computes in- and out-flows for each basic block (that's what MethodTFA does).

   For the purposes of Inliner, doing so guarantees that an abstract typestack-slot is available by the time an inlining candidate (a CALL_METHOD instruction) is visited. This subclass (MTFAGrowable) of MethodTFA also aims at performing such analysis on CALL_METHOD instructions, with some differences:

   (a) early screening is performed while the type-flow is being computed (in an override of `blockTransfer`) by testing a subset of the conditions that Inliner checks later. The reasoning here is: if the early check fails at some iteration, there's no chance a follow-up iteration (with a yet more lub-ed typestack-slot) will succeed. Failure is sufficient to remove that particular CALL_METHOD from the typeflow's `remainingCALLs`. A forward note: in case inlining occurs at some basic block B, all blocks reachable from B get their CALL_METHOD instructions considered again as candidates (because of the more precise types that -- perhaps -- can be computed).

   (b) in case the early check does not fail, no conclusive decision can be made, thus the CALL_METHOD stays `isOnwatchlist`.

   In other words, `remainingCALLs` tracks those callsites that still remain as candidates for inlining, so that Inliner can focus on those. `remainingCALLs` also caches info about the typestack just before the callsite, so as to spare computing them again at inlining time.

   Besides caching, a further optimization involves skipping those basic blocks whose in-flow and out-flow isn't needed anyway (as explained next). A basic block lacking a callsite in `remainingCALLs`, when visited by the standard algorithm, won't cause any inlining. But as we know from the way type-flows are computed, computing the in- and out-flow for a basic block relies in general on those of other basic blocks. In detail, we want to focus on that sub-graph of the CFG such that control flow may reach a remaining candidate callsite. Those basic blocks not in that subgraph can be skipped altogether. That's why:

   - `forwardAnalysis()` in `MTFAGrowable` now checks for inclusion of a basic block in `relevantBBs`
   - same check is performed before adding a block to the worklist, and as part of choosing successors. The bookkeeping supporting on-the-fly pruning of irrelevant blocks requires overriding most methods of the dataflow-analysis.

   The rest of the story takes place in Inliner, which does not visit all of the method's basic blocks but only on those represented in `remainingCALLs`.

   Definition Classes
     TypeFlowAnalysis

3. #### class MethodTFA extends DataFlowAnalysis[typeFlowLattice.type]

   Definition Classes
     TypeFlowAnalysis

4. #### class Timer extends AnyRef

   Definition Classes
     TypeFlowAnalysis

5. #### class VarBinding extends HashMap[Global.icodes.Local, Global.icodes.TypeKind]

   A map which returns the bottom type for unfound elements

   A map which returns the bottom type for unfound elements

   Definition Classes
     TypeFlowAnalysis

### Value Members

1. #### final def !=(arg0: Any): Boolean

   Test two objects for inequality.

   Test two objects for inequality.

   returns

     `true` if !(this == that), false otherwise.

   Definition Classes
     AnyRef → Any

2. #### final def ##(): Int

   Equivalent to `x.hashCode` except for boxed numeric types and `null`.

   Equivalent to `x.hashCode` except for boxed numeric types and `null`. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. For `null` returns a hashcode where `null.hashCode` throws a `NullPointerException`.

   returns

     a hash value consistent with ==

   Definition Classes
     AnyRef → Any

3. #### final def ==(arg0: Any): Boolean

   The expression `x == that` is equivalent to `if (x eq null) that eq null else x.equals(that)`.

   The expression `x == that` is equivalent to `if (x eq null) that eq null else x.equals(that)`.

   returns

     `true` if the receiver object is equivalent to the argument; `false` otherwise.

   Definition Classes
     AnyRef → Any

4. #### final def asInstanceOf[T0]: T0

   Cast the receiver object to be of type `T0`.

   Cast the receiver object to be of type `T0`.

   Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression `1.asInstanceOf[String]` will throw a `ClassCastException` at runtime, while the expression `List(1).asInstanceOf[List[String]]` will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.

   returns

     the receiver object.

   Definition Classes
     Any
   Exceptions thrown

     `ClassCastException` if the receiver object is not an instance of the erasure of type `T0`.

5. #### def clone(): AnyRef

   Create a copy of the receiver object.

   Create a copy of the receiver object.

   The default implementation of the `clone` method is platform dependent.

   returns

     a copy of the receiver object.

   Attributes
     protected[java.lang]
   Definition Classes
     AnyRef
   Annotations
     @throws( ... )
   Note

     not specified by SLS as a member of AnyRef

6. #### final def eq(arg0: AnyRef): Boolean

   Tests whether the argument (`that`) is a reference to the receiver object (`this`).

   Tests whether the argument (`that`) is a reference to the receiver object (`this`).

   The `eq` method implements an equivalence relation on non-null instances of `AnyRef`, and has three additional properties:

   - It is consistent: for any non-null instances `x` and `y` of type `AnyRef`, multiple invocations of `x.eq(y)` consistently returns `true` or consistently returns `false`.
   - For any non-null instance `x` of type `AnyRef`, `x.eq(null)` and `null.eq(x)` returns `false`.
   - `null.eq(null)` returns `true`.

   When overriding the `equals` or `hashCode` methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (`o1 eq o2`), they should be equal to each other (`o1 == o2`) and they should hash to the same value (`o1.hashCode == o2.hashCode`).

   returns

     `true` if the argument is a reference to the receiver object; `false` otherwise.

   Definition Classes
     AnyRef

7. #### def equals(arg0: Any): Boolean

   The equality method for reference types.

   The equality method for reference types. Default implementation delegates to `eq`.

   See also `equals` in scala.Any.

   returns

     `true` if the receiver object is equivalent to the argument; `false` otherwise.

   Definition Classes
     AnyRef → Any

8. #### def finalize(): Unit

   Called by the garbage collector on the receiver object when there are no more references to the object.

   Called by the garbage collector on the receiver object when there are no more references to the object.

   The details of when and if the `finalize` method is invoked, as well as the interaction between `finalize` and non-local returns and exceptions, are all platform dependent.

   Attributes
     protected[java.lang]
   Definition Classes
     AnyRef
   Annotations
     @throws( classOf[java.lang.Throwable] )
   Note

     not specified by SLS as a member of AnyRef

9. #### final def getClass(): Class[_]

   A representation that corresponds to the dynamic class of the receiver object.

   A representation that corresponds to the dynamic class of the receiver object.

   The nature of the representation is platform dependent.

   returns

     a representation that corresponds to the dynamic class of the receiver object.

   Definition Classes
     AnyRef → Any
   Note

     not specified by SLS as a member of AnyRef

10. #### val global: Global.this.type

    Definition Classes
      analysis → TypeFlowAnalysis

11. #### def hashCode(): Int

    The hashCode method for reference types.

    The hashCode method for reference types. See hashCode in scala.Any.

    returns

      the hash code value for this object.

    Definition Classes
      AnyRef → Any

12. #### final def isInstanceOf[T0]: Boolean

    Test whether the dynamic type of the receiver object is `T0`.

    Test whether the dynamic type of the receiver object is `T0`.

    Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression `1.isInstanceOf[String]` will return `false`, while the expression `List(1).isInstanceOf[List[String]]` will return `true`. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.

    returns

      `true` if the receiver object is an instance of erasure of type `T0`; `false` otherwise.

    Definition Classes
      Any

13. #### final def ne(arg0: AnyRef): Boolean

    Equivalent to `!(this eq that)`.

    Equivalent to `!(this eq that)`.

    returns

      `true` if the argument is not a reference to the receiver object; `false` otherwise.

    Definition Classes
      AnyRef

14. #### final def notify(): Unit

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Definition Classes
      AnyRef
    Note

      not specified by SLS as a member of AnyRef

15. #### final def notifyAll(): Unit

    Wakes up all threads that are waiting on the receiver object's monitor.

    Wakes up all threads that are waiting on the receiver object's monitor.

    Definition Classes
      AnyRef
    Note

      not specified by SLS as a member of AnyRef

16. #### final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
      AnyRef

17. #### val timer: Timer

    Definition Classes
      TypeFlowAnalysis

18. #### def toString(): String

    Creates a String representation of this object.

    Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.

    returns

      a String representation of the object.

    Definition Classes
      AnyRef → Any

19. #### object typeFlowLattice extends SemiLattice

    The type flow lattice contains a binding from local variable names to types and a type stack.

    The type flow lattice contains a binding from local variable names to types and a type stack.

    Definition Classes
      TypeFlowAnalysis

20. #### object typeLattice extends SemiLattice

    The lattice of ICode types.

    The lattice of ICode types.

    Definition Classes
      TypeFlowAnalysis

21. #### object typeStackLattice extends SemiLattice

    The lattice of type stacks.

    The lattice of type stacks. It is a straight forward extension of the type lattice (lub is pairwise lub of the list elements).

    Definition Classes
      TypeFlowAnalysis

22. #### final def wait(): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

23. #### final def wait(arg0: Long, arg1: Int): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

24. #### final def wait(arg0: Long): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

### Inherited from TypeFlowAnalysis

### Inherited from AnyRef

### Inherited from Any

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