Class BytecodeHelper


  • public class BytecodeHelper
    extends Object
    A helper class for bytecode generation with AsmClassGenerator.
    • Constructor Detail

      • BytecodeHelper

        public BytecodeHelper()
    • Method Detail

      • getClassInternalName

        public static String getClassInternalName​(ClassNode t)
        Returns:
        the ASM internal name of the type
      • getClassInternalName

        public static String getClassInternalName​(Class t)
        Returns:
        the ASM internal name of the type
      • getClassInternalName

        public static String getClassInternalName​(String name)
        Returns:
        the ASM internal name of the type
      • getMethodDescriptor

        public static String getMethodDescriptor​(MethodNode methodNode)
        Returns a method descriptor for the given MethodNode.
        Parameters:
        methodNode - the method node for which to create the descriptor
        Returns:
        a method descriptor as defined in section JVMS section 4.3.3
      • getMethodDescriptor

        public static String getMethodDescriptor​(ClassNode returnType,
                                                 Parameter[] parameters)
        Returns:
        the ASM method type descriptor
      • getMethodDescriptor

        public static String getMethodDescriptor​(ClassNode returnType,
                                                 ClassNode[] parameterTypes)
        Returns:
        the ASM method type descriptor
      • getMethodDescriptor

        public static String getMethodDescriptor​(Class returnType,
                                                 Class[] paramTypes)
        Returns:
        the ASM method type descriptor
      • getClassLoadingTypeDescription

        public static String getClassLoadingTypeDescription​(ClassNode c)
        array types are special: eg.: String[]: classname: [Ljava.lang.String; Object: classname: java.lang.Object int[] : classname: [I unlike getTypeDescription '.' is not replaced by '/'. it seems that makes problems for the class loading if '.' is replaced by '/'
        Returns:
        the ASM type description for class loading
      • getTypeDescription

        public static String getTypeDescription​(Class c)
      • getTypeDescription

        public static String getTypeDescription​(ClassNode c)
        array types are special: eg.: String[]: classname: [Ljava/lang/String; int[]: [I
        Returns:
        the ASM type description
      • getClassInternalNames

        public static String[] getClassInternalNames​(ClassNode[] names)
        Returns:
        an array of ASM internal names of the type
      • pushConstant

        public static void pushConstant​(org.objectweb.asm.MethodVisitor mv,
                                        int value)
      • negateBoolean

        public static void negateBoolean​(org.objectweb.asm.MethodVisitor mv)
        Negate a boolean on stack.
      • formatNameForClassLoading

        public static String formatNameForClassLoading​(String name)
        returns a name that Class.forName() can take. Notably for arrays: [I, [Ljava.lang.String; etc Regular object type: java.lang.String
      • getGenericsMethodSignature

        public static String getGenericsMethodSignature​(MethodNode node)
      • getGenericsSignature

        public static String getGenericsSignature​(ClassNode node)
      • getGenericsBounds

        public static String getGenericsBounds​(ClassNode type)
      • doCast

        public static void doCast​(org.objectweb.asm.MethodVisitor mv,
                                  ClassNode type)
      • doCastToPrimitive

        public static void doCastToPrimitive​(org.objectweb.asm.MethodVisitor mv,
                                             ClassNode sourceType,
                                             ClassNode targetType)
        Given a wrapped number type (Byte, Integer, Short, ...), generates bytecode to convert it to a primitive number (int, long, double) using calls to wrapped.[targetType]Value()
        Parameters:
        mv - method visitor
        sourceType - the wrapped number type
        targetType - the primitive target type
      • doCastToWrappedType

        public static void doCastToWrappedType​(org.objectweb.asm.MethodVisitor mv,
                                               ClassNode sourceType,
                                               ClassNode targetType)
        Given a primitive number type (byte, integer, short, ...), generates bytecode to convert it to a wrapped number (Integer, Long, Double) using calls to [WrappedType].valueOf
        Parameters:
        mv - method visitor
        sourceType - the primitive number type
        targetType - the wrapped target type
      • doCast

        public static void doCast​(org.objectweb.asm.MethodVisitor mv,
                                  Class type)
      • box

        @Deprecated
        public static boolean box​(org.objectweb.asm.MethodVisitor mv,
                                  ClassNode type)
        Deprecated.
        Generates the bytecode to autobox the current value on the stack.
      • box

        @Deprecated
        public static boolean box​(org.objectweb.asm.MethodVisitor mv,
                                  Class type)
        Deprecated.
        Generates the bytecode to autobox the current value on the stack.
      • unbox

        public static void unbox​(org.objectweb.asm.MethodVisitor mv,
                                 ClassNode type)
        Generates the bytecode to unbox the current value on the stack.
      • unbox

        public static void unbox​(org.objectweb.asm.MethodVisitor mv,
                                 Class type)
        Generates the bytecode to unbox the current value on the stack.
      • visitClassLiteral

        public static void visitClassLiteral​(org.objectweb.asm.MethodVisitor mv,
                                             ClassNode classNode)
        Visits a class literal. If the type of the classnode is a primitive type, the generated bytecode will be a GETSTATIC Integer.TYPE. If the classnode is not a primitive type, we will generate a LDC instruction.
      • isClassLiteralPossible

        public static boolean isClassLiteralPossible​(ClassNode classNode)
        Tells if a class node is candidate for class literal bytecode optimization. If so, bytecode may use LDC instructions instead of static constant Class fields to retrieve class literals.
        Parameters:
        classNode - the classnode for which we want to know if bytecode optimization is possible
        Returns:
        true if the bytecode can be optimized
      • isSameCompilationUnit

        public static boolean isSameCompilationUnit​(ClassNode a,
                                                    ClassNode b)
        Returns true if the two classes share the same compilation unit.
        Parameters:
        a - class a
        b - class b
        Returns:
        true if both classes share the same compilation unit
      • hashCode

        public static int hashCode​(String str)
        Computes a hash code for a string. The purpose of this hashcode is to be constant independently of the JDK being used.
        Parameters:
        str - the string for which to compute the hashcode
        Returns:
        hashcode of the string
      • convertPrimitiveToBoolean

        public static void convertPrimitiveToBoolean​(org.objectweb.asm.MethodVisitor mv,
                                                     ClassNode type)
        Converts a primitive type to boolean.
        Parameters:
        mv - method visitor
        type - primitive type to convert
      • doReturn

        public static void doReturn​(org.objectweb.asm.MethodVisitor mv,
                                    ClassNode type)
      • load

        public static void load​(org.objectweb.asm.MethodVisitor mv,
                                ClassNode type,
                                int idx)
      • store

        public static void store​(org.objectweb.asm.MethodVisitor mv,
                                 ClassNode type,
                                 int idx)