Scala Compiler2.12.7 < Back
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# Packages

-  package root

  The Scala compiler and reflection APIs.

  The Scala compiler and reflection APIs.

  Definition Classes
    root
-  package scala
  Definition Classes
    root
-  package tools
  Definition Classes
    scala
-  package nsc
  Definition Classes
    tools
-  package backend
  Definition Classes
    nsc
-  package jvm
  Definition Classes
    backend
-  package analysis

  Summary on the ASM analyzer framework --------------------------------------

  Summary on the ASM analyzer framework --------------------------------------

  Value

  - Abstract, needs to be implemented for each analysis.
  - Represents the desired information about local variables and stack values, for example:
    - Is this value known to be null / not null?
    - What are the instructions that could potentially have produced this value?

  Interpreter

  - Abstract, needs to be implemented for each analysis. Sometimes one can subclass an existing interpreter, e.g., SourceInterpreter or BasicInterpreter.
  - Multiple abstract methods that receive an instruction and the instruction's input values, and return a value representing the result of that instruction.
    - Note: due to control flow, the interpreter can be invoked multiple times for the same instruction, until reaching a fixed point.
  - Abstract `merge` function that computes the least upper bound of two values. Used by Frame.merge (see below).

  Frame

  - Can be used directly for many analyses, no subclass required.
  - Every frame has an array of values: one for each local variable and for each stack slot.
    - A `top` index stores the index of the current stack top
    - NOTE: for a size-2 local variable at index i, the local variable at i+1 is set to an empty value. However, for a size-2 value at index i on the stack, the value at i+1 holds the next stack value. IMPORTANT: this is only the case in ASM's analysis framework, not in bytecode. See comment below.
  - Defines the `execute(instruction)` method.
    - executing mutates the state of the frame according to the effect of the instruction
      - pop consumed values from the stack
      - pass them to the interpreter together with the instruction
      - if applicable, push the resulting value on the stack
  - Defines the `merge(otherFrame)` method
    - called by the analyzer when multiple control flow paths lead to an instruction
      - the frame at the branching instruction is merged into the current frame of the instruction (held by the analyzer)
      - mutates the values of the current frame, merges all values using interpreter.merge.

  Analyzer

  - Stores a frame for each instruction
  - `merge` function takes an instruction and a frame, merges the existing frame for that instr (from the frames array) with the new frame passed as argument. if the frame changed, puts the instruction on the work queue (fixpoint).
  - initial frame: initialized for first instr by calling interpreter.new[...]Value for each slot (locals and params), stored in frames[firstInstr] by calling `merge`
  - work queue of instructions (`queue` array, `top` index for next instruction to analyze)
  - analyze(method): simulate control flow. while work queue non-empty:
    - copy the state of `frames[instr]` into a local frame `current`
    - call `current.execute(instr, interpreter)`, mutating the `current` frame
    - if it's a branching instruction
      - for all potential destination instructions
        - merge the destination instruction frame with the `current` frame (this enqueues the destination instr if its frame changed)
      - invoke `newControlFlowEdge` (see below)
  - the analyzer also tracks active exception handlers at each instruction
  - the empty method `newControlFlowEdge` can be overridden to track control flow if required

  MaxLocals and MaxStack ----------------------

  At the JVM level, long and double values occupy two slots, both as local variables and on the stack, as specified in the JVM spec 2.6.2: "At any point in time, an operand stack has an associated depth, where a value of type long or double contributes two units to the depth and a value of any other type contributes one unit."

  For example, a method class A { def f(a: Long, b: Long) = a + b } has MAXSTACK=4 in the classfile. This value is computed by the ClassWriter / MethodWriter when generating the classfile (we always pass COMPUTE_MAXS to the ClassWriter).

  For running an ASM Analyzer, long and double values occupy two local variable slots, but only a single slot on the call stack, as shown by the following snippet:

  import scala.tools.nsc.backend.jvm._ import scala.tools.nsc.backend.jvm.opt.BytecodeUtils._ import scala.collection.convert.decorateAsScala._ import scala.tools.asm.tree.analysis._

  val cn = AsmUtils.readClass("/Users/luc/scala/scala/sandbox/A.class") val m = cn.methods.iterator.asScala.find(_.name == "f").head

  // the value is read from the classfile, so it's 4 println(s"maxLocals: ${m.maxLocals}, maxStack: ${m.maxStack}") // maxLocals: 5, maxStack: 4

  // we can safely set it to 2 for running the analyzer. m.maxStack = 2

  val a = new Analyzer(new BasicInterpreter) a.analyze(cn.name, m) val addInsn = m.instructions.iterator.asScala.find(_.getOpcode == 97).get // LADD Opcode val addFrame = a.frameAt(addInsn, m)

  addFrame.getStackSize // 2: the two long values only take one slot each addFrame.getLocals // 5: this takes one slot, the two long parameters take 2 slots each

  While running the optimizer, we need to make sure that the `maxStack` value of a method is large enough for running an ASM analyzer. We don't need to worry if the value is incorrect in the JVM perspective: the value will be re-computed and overwritten in the ClassWriter.

  Lessons learnt while benchmarking the alias tracking analysis -------------------------------------------------------------

  Profiling

  - Use YourKit for finding hotspots (cpu profiling). when it comes to drilling down into the details of a hotspot, don't pay too much attention to the percentages / time counts.
  - Should also try other profilers.
  - Use timers. When a method showed up as a hotspot, I added a timer around that method, and a second one within the method to measure specific parts. The timers slow things down, but the relative numbers show what parts of a method are slow.

  ASM analyzer insights

  - The time for running an analysis depends on the number of locals and the number of instructions. Reducing the number of locals helps speeding up the analysis: there are less values to merge when merging to frames. See also https://github.com/scala/scala-dev/issues/47
  - The common hot spot of an ASM analysis is Frame.merge, for example in producers / consumers.
  - For nullness analysis the time is spent as follows
    - 20% merging nullness values. this is as expected: for example, the same absolute amount of time is spent in merging BasicValues when running a BasicInterpreter.
    - 50% merging alias sets. i tried to optimize what i could out of this.
    - 20% is spent creating new frames from existing ones, see comment on AliasingFrame.init.
  - The implementation of Frame.merge (the main hot spot) contains a megamorphic callsite to `interpreter.merge`. This can be observed easily by running a test program that either runs a BasicValue analysis only, versus a program that first runs a nullness analysis and then a BasicValue. In an example, the time for the BasicValue analysis goes from 519ms to 1963ms, a 3.8x slowdown.
  - I added counters to the Frame.merge methods for nullness and BasicValue analysis. In the examples I benchmarked, the number of merge invocations was always exactly the same. It would probably be possible to come up with an example where alias set merging forces additional analysis rounds until reaching the fixpoint, but I did not observe such cases.

  To benchmark an analysis, instead of benchmarking analysis while it runs in the compiler backend, one can easily run it from a separate program (or the repl). The bytecode to analyze can simply be parsed from a classfile. See example at the end of this comment.

  Nullness Analysis in Miguel's Optimizer ---------------------------------------

  Miguel implemented alias tracking for nullness analysis differently [1]. Remember that every frame has an array of values. Miguel's idea was to represent aliasing using reference equality in the values array: if two entries in the array point to the same value object, the two entries are aliases in the frame of the given instruction.

  While this idea seems elegant at first sight, Miguel's implementation does not merge frames correctly when it comes to aliasing. Assume in frame 1, values (a, b, c) are aliases, while in frame 2 (a, b) are aliases. When merging the second into the first, we have to make sure that c is removed as an alias of (a, b).

  It would be possible to implement correct alias set merging in Miguel's approach. However, frame merging is the main hot spot of analysis. The computational complexity of implementing alias set merging by traversing the values array and comparing references is too high. The concrete alias set representation that is used in the current implementation (see class AliasingFrame) makes alias set merging more efficient.

  [1] https://github.com/scala-opt/scala/blob/opt/rebase/src/compiler/scala/tools/nsc/backend/bcode/NullnessPropagator.java

  Complexity and scaling of analysis ----------------------------------

  The time complexity of a data flow analysis depends on:

  - The size of the method. The complexity factor is linear (assuming the number of locals and branching instructions remains constant). The main analysis loop runs through all instructions of a method once. Instructions are only re-enqueued if a control flow merge changes the frame at some instruction.
  - The branching instructions. When a second (third, ..) control flow edge arrives at an instruction, the existing frame at the instruction is merged with the one computed on the new branch. If the merge function changes the existing frame, the instruction is enqueued for another analysis. This results in a merge operation for the successors of the instruction.
  - The number of local variables. The hot spot of analysis is frame merging. The merge function iterates through the values in the frame (locals and stack values) and merges them.

  I measured the running time of an analysis for two examples:

  - Keep the number of locals and branching instructions constant, increase the number of instructions. The running time grows linearly with the method size.
  - Increase the size and number of locals in a method. The method size and number of locals grow in the same pace. Here, the running time increase is polynomial. It looks like the complexity is be #instructions * #locals^2 (see below).

  I measured nullness analysis (which tracks aliases) and a SimpleValue analysis. Nullness runs roughly 5x slower (because of alias tracking) at every problem size - this factor doesn't change.

  The numbers below are for nullness. Note that the last column is constant, i.e., the running time is proportional to #ins * #loc^2. Therefore we use this factor when limiting the maximal method size for running an analysis.

  #insns #locals time (ms) time / #ins * #loc2 * 106 1305 156 34 1.07 2610 311 165 0.65 3915 466 490 0.57 5220 621 1200 0.59 6525 776 2220 0.56 7830 931 3830 0.56 9135 1086 6570 0.60 10440 1241 9700 0.60 11745 1396 13800 0.60

  As a second experiment, nullness analysis was run with varying #insns but constant #locals. The last column shows linear complexity with respect to the method size (linearOffset = 2279):

  #insns #locals time (ms) (time + linearOffset) / #insns 5220 621 1090 0.645 6224 621 1690 0.637 7226 621 2280 0.630 8228 621 2870 0.625 9230 621 3530 0.629 10232 621 4130 0.626 11234 621 4770 0.627 12236 621 5520 0.637 13238 621 6170 0.638

  When running a BasicValue analysis, the complexity observation is the same (time is proportional to #ins * #loc^2).

  Measuring analysis execution time ---------------------------------

  See code below.

  Definition Classes
    jvm
-  package opt
  Definition Classes
    jvm
- AsmUtils
- BCodeBodyBuilder
- BCodeHelpers
- BCodeIdiomatic
- BCodeSkelBuilder
- BCodeSyncAndTry
- BTypes
- BTypesFromClassfile
- BTypesFromSymbols
- BackendReporting
- BackendStats
- ClassNode1
- ClassfileWriters
- CodeGen
- CompilationUnitInPostProcess
- CompilationUnitPaths
- CoreBTypes
- CoreBTypesFromSymbols
- FlatConcurrentHashMap
- GenBCode
- GeneratedClass
- GeneratedCompilationUnit
- LabelNode1
- MethodNode1
- PerRunInit
- PostProcessor
- PostProcessorFrontendAccess

c

scala.tools.nsc.backend.jvm

# BTypesFromSymbols 

###

#### abstract class BTypesFromSymbols[G <: Global] extends BTypes

This class mainly contains the method classBTypeFromSymbol, which extracts the necessary information from a symbol and its type to create the corresponding ClassBType. It requires access to the compiler (global parameter).

Source
  BTypesFromSymbols.scala

Linear Supertypes
BTypes, AnyRef, Any
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Ordering

1. Alphabetic
2. By Inheritance

Inherited

1. BTypesFromSymbols
2. BTypes
3. AnyRef
4. Any

Implicitly

1. by any2stringadd
2. by StringFormat
3. by Ensuring
4. by ArrowAssoc

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Visibility

1. Public
2. All

### Instance Constructors

1.  new BTypesFromSymbols(global: G)

### Type Members

1.  final case class ArrayBType(componentType: BType) extends RefBType with Product with Serializable
   Definition Classes
     BTypes
2.  sealed trait BType extends AnyRef

   A BType is either a primitive type, a ClassBType, an ArrayBType of one of these, or a MethodType referring to BTypes.

   A BType is either a primitive type, a ClassBType, an ArrayBType of one of these, or a MethodType referring to BTypes.

   Definition Classes
     BTypes
3.  sealed abstract class ClassBType extends RefBType

   A ClassBType represents a class or interface type.

   A ClassBType represents a class or interface type. The necessary information to build a ClassBType is extracted from compiler symbols and types, see BTypesFromSymbols.

   The `info` field contains either the class information on an error message why the info could not be computed. There are two reasons for an erroneous info:

   1. The ClassBType was built from a class symbol that stems from a java source file, and the symbol's type could not be completed successfully (scala/bug#9111) 2. The ClassBType should be built from a classfile, but the class could not be found on the compilation classpath.

   Note that all ClassBTypes required in a non-optimized run are built during code generation from the class symbols referenced by the ASTs, so they have a valid info. Therefore the backend often invokes `info.get` (which asserts the info to exist) when reading data from the ClassBType.

   The inliner on the other hand uses ClassBTypes that are built from classfiles, which may have a missing info. In order not to crash the compiler unnecessarily, the inliner does not force infos using `get`, but it reports inliner warnings for missing infos that prevent inlining.

   Definition Classes
     BTypes
4.  final case class ClassInfo(superClass: Option[ClassBType], interfaces: List[ClassBType], flags: Int, nestedClasses: Lazy[List[ClassBType]], nestedInfo: Lazy[Option[NestedInfo]], inlineInfo: InlineInfo) extends Product with Serializable

   The type info for a class.

   The type info for a class. Used for symboltable-independent subtype checks in the backend.

   superClass

     The super class, not defined for class java/lang/Object.

   interfaces

     All transitively implemented interfaces, except for those inherited through the superclass.

   flags

     The java flags, obtained through `javaFlags`. Used also to derive the flags for InnerClass entries.

   nestedClasses

     Classes nested in this class. Those need to be added to the InnerClass table, see the InnerClass spec summary above.

   nestedInfo

     If this describes a nested class, information for the InnerClass table.

   inlineInfo

     Information about this class for the inliner.

   Definition Classes
     BTypes
5.  final case class InnerClassEntry(name: String, outerName: String, innerName: String, flags: Int) extends Product with Serializable

   This class holds the data for an entry in the InnerClass table.

   This class holds the data for an entry in the InnerClass table. See the InnerClass summary above in this file.

   There's some overlap with the class NestedInfo, but it's not exactly the same and cleaner to keep separate.

   name

     The internal name of the class.

   outerName

     The internal name of the outer class, may be null.

   innerName

     The simple name of the inner class, may be null.

   flags

     The flags for this class in the InnerClass entry.

   Definition Classes
     BTypes
6.  sealed abstract class Lazy[+T] extends AnyRef
   Definition Classes
     BTypes
7.  class LazyVar[T] extends AnyRef

   This implements a lazy value that can be reset and re-initialized.

   This implements a lazy value that can be reset and re-initialized. It synchronizes on `frontendLock` so that lazy state created through this utility can be safely initialized in the post-processor.

   Note that values defined as `LazyVar`s are usually `lazy val`s themselves (created through the `perRunLazy` method). This ensures that re-initializing a component only clears those `LazyVar`s that have actually been used in the previous compiler run.

   Definition Classes
     BTypes
8.  final case class MethodBType(argumentTypes: List[BType], returnType: BType) extends BType with Product with Serializable
   Definition Classes
     BTypes
9.  final case class MethodNameAndType(name: String, methodType: MethodBType) extends Product with Serializable

   Just a named pair, used in CoreBTypes.srBoxesRuntimeBoxToMethods/srBoxesRuntimeUnboxToMethods.

   Just a named pair, used in CoreBTypes.srBoxesRuntimeBoxToMethods/srBoxesRuntimeUnboxToMethods.

   Definition Classes
     BTypes
10.  final case class NestedInfo(enclosingClass: ClassBType, outerName: Option[String], innerName: Option[String], isStaticNestedClass: Boolean) extends Product with Serializable

    Information required to add a class to an InnerClass table.

    Information required to add a class to an InnerClass table. The spec summary above explains what information is required for the InnerClass entry.

    enclosingClass

      The enclosing class, if it is also nested. When adding a class to the InnerClass table, enclosing nested classes are also added.

    outerName

      The outerName field in the InnerClass entry, may be None.

    innerName

      The innerName field, may be None.

    isStaticNestedClass

      True if this is a static nested class (not inner class) (*) (*) Note that the STATIC flag in ClassInfo.flags, obtained through javaFlags(classSym), is not correct for the InnerClass entry, see javaFlags. The static flag in the InnerClass describes a source-level property: if the class is in a static context (does not have an outer pointer). This is checked when building the NestedInfo.

    Definition Classes
      BTypes
11.  sealed trait PrimitiveBType extends BType
    Definition Classes
      BTypes
12.  sealed trait RefBType extends BType
    Definition Classes
      BTypes

### Abstract Value Members

1.  abstract val frontendAccess: PostProcessorFrontendAccess
   Definition Classes
     BTypesFromSymbols → BTypes

### Concrete Value Members

1.  object BOOL extends PrimitiveBType with Product with Serializable
   Definition Classes
     BTypes
2.  object BYTE extends PrimitiveBType with Product with Serializable
   Definition Classes
     BTypes
3.  object CHAR extends PrimitiveBType with Product with Serializable
   Definition Classes
     BTypes
4.  object ClassBType
   Definition Classes
     BTypes
5.  object DOUBLE extends PrimitiveBType with Product with Serializable
   Definition Classes
     BTypes
6.  object FLOAT extends PrimitiveBType with Product with Serializable
   Definition Classes
     BTypes
7.  object INT extends PrimitiveBType with Product with Serializable
   Definition Classes
     BTypes
8.  object LONG extends PrimitiveBType with Product with Serializable
   Definition Classes
     BTypes
9.  object Lazy
   Definition Classes
     BTypes
10.  object SHORT extends PrimitiveBType with Product with Serializable
    Definition Classes
      BTypes
11.  object UNIT extends PrimitiveBType with Product with Serializable
    Definition Classes
      BTypes
12.  final def !=(arg0: Any): Boolean
    Definition Classes
      AnyRef → Any
13.  final def ##(): Int
    Definition Classes
      AnyRef → Any
14.  def +(other: String): String
    Implicit
      This member is added by an implicit conversion from BTypesFromSymbols[G] to any2stringadd[BTypesFromSymbols[G]] performed by method any2stringadd in scala.Predef.
    Definition Classes
      any2stringadd
15.  def ->[B](y: B): (BTypesFromSymbols[G], B)
    Implicit
      This member is added by an implicit conversion from BTypesFromSymbols[G] to ArrowAssoc[BTypesFromSymbols[G]] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
      ArrowAssoc
    Annotations
      @inline()
16.  final def ==(arg0: Any): Boolean
    Definition Classes
      AnyRef → Any
17.  final def asInstanceOf[T0]: T0
    Definition Classes
      Any
18.  def assertClassNotArray(sym: G.Symbol): Unit
19.  def assertClassNotArrayNotPrimitive(sym: G.Symbol): Unit
20.  def beanInfoClassClassBType(mainClass: G.Symbol): ClassBType
21.  def bootstrapMethodArg(t: G.Constant, pos: G.Position): AnyRef
22.  def buildInlineInfoFromClassSymbol(classSym: G.Symbol): InlineInfo

    Build the InlineInfo for a class symbol.

23.  def cachedClassBType(internalName: InternalName): Option[ClassBType]

    Every ClassBType is cached on construction and accessible through this method.

    Every ClassBType is cached on construction and accessible through this method.

    The cache is used when computing stack map frames. The asm.ClassWriter invokes the method `getCommonSuperClass`. In this method we need to obtain the ClassBType for a given internal name. The method assumes that every class type that appears in the bytecode exists in the map

    Definition Classes
      BTypes
24.  val classBTypeCache: Map[InternalName, ClassBType]
    Definition Classes
      BTypes
25.  final def classBTypeFromSymbol(sym: G.Symbol): ClassBType

    The ClassBType for a class symbol `classSym`.

    The ClassBType for a class symbol `classSym`.

    The class symbol scala.Nothing is mapped to the class scala.runtime.Nothing$. Similarly, scala.Null is mapped to scala.runtime.Null$. This is because there exist no class files for the Nothing / Null. If used for example as a parameter type, we use the runtime classes in the classfile method signature.

26.  def clone(): AnyRef
    Attributes
      protected[java.lang]
    Definition Classes
      AnyRef
    Annotations
      @native() @throws( ... )
27.  val coreBTypes: CoreBTypesFromSymbols[G] { val bTypes: BTypesFromSymbols.this.type }
    Definition Classes
      BTypesFromSymbols → BTypes
28.  def ensuring(cond: (BTypesFromSymbols[G]) ⇒ Boolean, msg: ⇒ Any): BTypesFromSymbols[G]
    Implicit
      This member is added by an implicit conversion from BTypesFromSymbols[G] to Ensuring[BTypesFromSymbols[G]] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
29.  def ensuring(cond: (BTypesFromSymbols[G]) ⇒ Boolean): BTypesFromSymbols[G]
    Implicit
      This member is added by an implicit conversion from BTypesFromSymbols[G] to Ensuring[BTypesFromSymbols[G]] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
30.  def ensuring(cond: Boolean, msg: ⇒ Any): BTypesFromSymbols[G]
    Implicit
      This member is added by an implicit conversion from BTypesFromSymbols[G] to Ensuring[BTypesFromSymbols[G]] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
31.  def ensuring(cond: Boolean): BTypesFromSymbols[G]
    Implicit
      This member is added by an implicit conversion from BTypesFromSymbols[G] to Ensuring[BTypesFromSymbols[G]] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
32.  final def eq(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
33.  def equals(arg0: Any): Boolean
    Definition Classes
      AnyRef → Any
34.  def finalize(): Unit
    Attributes
      protected[java.lang]
    Definition Classes
      AnyRef
    Annotations
      @throws( classOf[java.lang.Throwable] )
35.  def formatted(fmtstr: String): String
    Implicit
      This member is added by an implicit conversion from BTypesFromSymbols[G] to StringFormat[BTypesFromSymbols[G]] performed by method StringFormat in scala.Predef.
    Definition Classes
      StringFormat
    Annotations
      @inline()
36.  final def getClass(): Class[_]
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
37.  val global: G
38.  final def hasPublicBitSet(flags: Int): Boolean
39.  def hashCode(): Int
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
40.  def implementedInterfaces(classSym: G.Symbol): List[G.Symbol]
41.  final def initialize(): Unit
42.  def isCompilingArray: Boolean
43.  def isCompilingPrimitive: Boolean

    True if the current compilation unit is of a primitive class (scala.Boolean et al).

    True if the current compilation unit is of a primitive class (scala.Boolean et al). Used only in assertions.

    Definition Classes
      BTypesFromSymbols → BTypes
44.  final def isInstanceOf[T0]: Boolean
    Definition Classes
      Any
45.  final def isRemote(s: G.Symbol): Boolean
46.  final def isStaticModuleClass(sym: G.Symbol): Boolean

    True for module classes of modules that are top-level or owned only by objects.

    True for module classes of modules that are top-level or owned only by objects. Module classes for such objects will get a MODULE$ field and a corresponding static initializer.

47.  final def isTopLevelModuleClass(sym: G.Symbol): Boolean

    True for module classes of package level objects.

    True for module classes of package level objects. The backend will generate a mirror class for such objects.

48.  def javaFieldFlags(sym: G.Symbol): Int
49.  final def javaFlags(sym: G.Symbol): Int

    Return the Java modifiers for the given symbol.

    Return the Java modifiers for the given symbol. Java modifiers for classes:

    - public, abstract, final, strictfp (not used) for interfaces:
    - the same as for classes, without 'final' for fields:
    - public, private (*)
    - static, final for methods:
    - the same as for fields, plus:
    - abstract, synchronized (not used), strictfp (not used), native (not used) for all:
    - deprecated

    (*) protected cannot be used, since inner classes 'see' protected members, and they would fail verification after lifted.

50.  final def methodBTypeFromMethodType(tpe: G.Type, isConstructor: Boolean): MethodBType

    Builds a MethodBType for a method type.

51.  final def methodBTypeFromSymbol(methodSymbol: G.Symbol): MethodBType

    Builds a MethodBType for a method symbol.

52.  def mirrorClassClassBType(moduleClassSym: G.Symbol): ClassBType

    For top-level objects without a companion class, the compiler generates a mirror class with static forwarders (Java compat).

    For top-level objects without a companion class, the compiler generates a mirror class with static forwarders (Java compat). There's no symbol for the mirror class, but we still need a ClassBType (its info.nestedClasses will hold the InnerClass entries, see comment in BTypes).

53.  final def ne(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
54.  final def notify(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
55.  final def notifyAll(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
56.  def perRunLazy[T](component: PerRunInit)(init: ⇒ T): LazyVar[T]

    Create state that lazily evaluated (to work around / not worry about initialization ordering issues).

    Create state that lazily evaluated (to work around / not worry about initialization ordering issues). The state is cleared in each compiler run when the component is initialized.

    Definition Classes
      BTypes
57.  def staticHandleFromSymbol(sym: G.Symbol): Handle
58.  final val strMODULE_INSTANCE_FIELD: String
59.  final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
      AnyRef
60.  def toString(): String
    Definition Classes
      AnyRef → Any
61.  final def typeToBType(t: G.Type): BType

    This method returns the BType for a type reference, for example a parameter type.

62.  final def wait(): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )
63.  final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )
64.  final def wait(arg0: Long): Unit
    Definition Classes
      AnyRef
    Annotations
      @native() @throws( ... )
65.  def →[B](y: B): (BTypesFromSymbols[G], B)
    Implicit
      This member is added by an implicit conversion from BTypesFromSymbols[G] to ArrowAssoc[BTypesFromSymbols[G]] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
      ArrowAssoc

### Inherited from BTypes

### Inherited from AnyRef

### Inherited from Any

### Inherited by implicit conversion any2stringadd from BTypesFromSymbols[G] to any2stringadd[BTypesFromSymbols[G]]

### Inherited by implicit conversion StringFormat from BTypesFromSymbols[G] to StringFormat[BTypesFromSymbols[G]]

### Inherited by implicit conversion Ensuring from BTypesFromSymbols[G] to Ensuring[BTypesFromSymbols[G]]

### Inherited by implicit conversion ArrowAssoc from BTypesFromSymbols[G] to ArrowAssoc[BTypesFromSymbols[G]]

### Ungrouped