BTypes
The BTypes component defines The BType class hierarchy. BTypes encapsulates all type information that is required after building the ASM nodes. This includes optimizations, geneartion of InnerClass attributes and generation of stack map frames.
This representation is immutable and independent of the compiler data structures, hence it can be queried by concurrent threads.
Type members
Classlikes
A BType is either a primitve type, a ClassBType, an ArrayBType of one of these, or a MethodType referring to BTypes.
A BType is either a primitve type, a ClassBType, an ArrayBType of one of these, or a MethodType referring to BTypes.
A ClassBType represents a class or interface type. The necessary information to build a ClassBType is extracted from compiler symbols and types, see BTypesFromSymbols.
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 offset and length fields are used to represent the internal name of the class. They
are indices into some character array. The internal name can be obtained through the method
internalNameString, which is abstract in this component. Name creation is assumed to be
hash-consed, so if two ClassBTypes have the same internal name, they NEED to have the same
offset and length.
The actual implementation in subclass BTypesFromSymbols uses the global chrs array from the
name table. This representation is efficient because the JVM class name is obtained through
classSymbol.javaBinaryName. This already adds the necessary string to the chrs array,
so it makes sense to reuse the same name table in the backend.
ClassBType is not a case class because we want a custom equals method, and because the extractor extracts the internalName, which is what you typically need.
- Companion:
- object
The type info for a class. Used for symboltable-independent subtype checks in the backend.
The type info for a class. Used for symboltable-independent subtype checks in the backend.
- Value parameters:
- flags
The java flags, obtained through
javaFlags. Used also to derive the flags for InnerClass entries.- interfaces
All transitively implemented interfaces, except for those inherited through the superclass.
- memberClasses
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.
- superClass
The super class, not defined for class java/lang/Object.
This class holds the data for an entry in the InnerClass table. See the InnerClass summary above in this file.
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.
- Value parameters:
- flags
The flags for this class in the InnerClass entry.
- innerName
The simple name of the inner class, may be null.
- name
The internal name of the class.
- outerName
The internal name of the outer class, may be null.
Just a named pair, used in CoreBTypes.asmBoxTo/asmUnboxTo.
Just a named pair, used in CoreBTypes.asmBoxTo/asmUnboxTo.
Information required to add a class to an InnerClass table. The spec summary above explains what information is required for the InnerClass entry.
Information required to add a class to an InnerClass table. The spec summary above explains what information is required for the InnerClass entry.
- Value parameters:
- enclosingClass
The enclosing class, if it is also nested. When adding a class to the InnerClass table, enclosing nested classes are also added.
- 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 propety: if the class is in a static context (does not have an outer pointer). This is checked when building the NestedInfo.
- outerName
The outerName field in the InnerClass entry, may be None.
Value members
Abstract methods
A map from internal names to ClassBTypes. Every ClassBType is added to this map on its construction.
A map from internal names to ClassBTypes. Every ClassBType is added to this map on its construction.
This map 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.
Concurrent because stack map frames are computed when in the class writer, which might run on multiple classes concurrently.