Package org.jacoco.core.internal.instr

Class InstrSupport

  • public final class InstrSupport
extends java.lang.Object
    Constants and utilities for byte code instrumentation.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static int ASM_API_VERSION
      ASM API version
      (package private) static int CLINIT_ACC
      Access flags of the interface initialization method generated by JaCoCo.
      (package private) static java.lang.String CLINIT_DESC
      Descriptor of the interface initialization method.
      (package private) static java.lang.String CLINIT_NAME
      Name of the interface initialization method.
      static int DATAFIELD_ACC
      Access modifiers of the field that stores coverage information of a class.
      static java.lang.String DATAFIELD_DESC
      Data type of the field that stores coverage information for a class ( boolean[]).
      static int DATAFIELD_INTF_ACC
      Access modifiers of the field that stores coverage information of a Java 8 interface.
      static java.lang.String DATAFIELD_NAME
      Name of the field that stores coverage information of a class.
      static int INITMETHOD_ACC
      Access modifiers of the initialization method.
      static java.lang.String INITMETHOD_DESC
      Descriptor of the initialization method.
      static java.lang.String INITMETHOD_NAME
      Name of the initialization method.

    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      private InstrSupport()  

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static void assertNotInstrumented​(java.lang.String member, java.lang.String owner)
      Ensures that the given member does not correspond to a internal member created by the instrumentation process.
      static org.objectweb.asm.ClassReader classReaderFor​(byte[] b)
      Creates a ClassReader instance for given bytes of class even if its version not yet supported by ASM.
      static int getMajorVersion​(byte[] b)
      Gets major version number from given bytes of class (unsigned two bytes at offset 6).
      static int getMajorVersion​(org.objectweb.asm.ClassReader reader)
      Gets major version number from given ClassReader.
      static boolean needsFrames​(int version)
      Determines whether the given class file version requires stackmap frames.
      static void push​(org.objectweb.asm.MethodVisitor mv, int value)
      Generates the instruction to push the given int value on the stack.
      static void setMajorVersion​(int majorVersion, byte[] b)
      Sets major version number in given bytes of class (unsigned two bytes at offset 6).

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • ASM_API_VERSION

        public static final int ASM_API_VERSION
        ASM API version
        See Also:
        Constant Field Values

      • DATAFIELD_NAME

        public static final java.lang.String DATAFIELD_NAME
        Name of the field that stores coverage information of a class.
        See Also:
        Constant Field Values

      • DATAFIELD_ACC

        public static final int DATAFIELD_ACC
        Access modifiers of the field that stores coverage information of a class. According to Java Virtual Machine Specification §6.5.putstatic this field must not be final:

        if the field is final, it must be declared in the current class, and the instruction must occur in the <clinit> method of the current class.

        See Also:
        Constant Field Values

      • DATAFIELD_INTF_ACC

        public static final int DATAFIELD_INTF_ACC
        Access modifiers of the field that stores coverage information of a Java 8 interface. According to Java Virtual Machine Specification §4.5:

        Fields of interfaces must have their ACC_PUBLIC, ACC_STATIC, and ACC_FINAL flags set; they may have their ACC_SYNTHETIC flag set and must not have any of the other flags.

        See Also:
        Constant Field Values

      • DATAFIELD_DESC

        public static final java.lang.String DATAFIELD_DESC
        Data type of the field that stores coverage information for a class ( boolean[]).
        See Also:
        Constant Field Values

      • INITMETHOD_NAME

        public static final java.lang.String INITMETHOD_NAME
        Name of the initialization method.
        See Also:
        Constant Field Values

      • INITMETHOD_DESC

        public static final java.lang.String INITMETHOD_DESC
        Descriptor of the initialization method.
        See Also:
        Constant Field Values

      • INITMETHOD_ACC

        public static final int INITMETHOD_ACC
        Access modifiers of the initialization method.
        See Also:
        Constant Field Values

      • CLINIT_NAME

        static final java.lang.String CLINIT_NAME
        Name of the interface initialization method. According to Java Virtual Machine Specification §2.9:

        A class or interface has at most one class or interface initialization method and is initialized by invoking that method. The initialization method of a class or interface has the special name <clinit>, takes no arguments, and is void.

        Other methods named <clinit> in a class file are of no consequence. They are not class or interface initialization methods. They cannot be invoked by any Java Virtual Machine instruction and are never invoked by the Java Virtual Machine itself.

        In a class file whose version number is 51.0 or above, the method must additionally have its ACC_STATIC flag set in order to be the class or interface initialization method.

        This requirement was introduced in Java SE 7. In a class file whose version number is 50.0 or below, a method named <clinit> that is void and takes no arguments is considered the class or interface initialization method regardless of the setting of its ACC_STATIC flag.

        And §4.6:

        Class and interface initialization methods are called implicitly by the Java Virtual Machine. The value of their access_flags item is ignored except for the setting of the ACC_STRICT flag.

        See Also:
        Constant Field Values

    • Constructor Detail

      • InstrSupport

        private InstrSupport()

    • Method Detail

      • setMajorVersion

        public static void setMajorVersion​(int majorVersion,
                                   byte[] b)
        Sets major version number in given bytes of class (unsigned two bytes at offset 6).
        Parameters:
        majorVersion - major version of bytecode to set
        b - bytes of class
        See Also:
        getMajorVersion(byte[])

      • getMajorVersion

        public static int getMajorVersion​(org.objectweb.asm.ClassReader reader)
        Gets major version number from given ClassReader.
        Parameters:
        reader - reader to get information about the class
        Returns:
        major version of bytecode
        See Also:
        ClassReader(byte[], int, int), getMajorVersion(byte[])

      • needsFrames

        public static boolean needsFrames​(int version)
        Determines whether the given class file version requires stackmap frames.
        Parameters:
        version - class file version
        Returns:
        true if frames are required

      • assertNotInstrumented

        public static void assertNotInstrumented​(java.lang.String member,
                                         java.lang.String owner)
                                  throws java.lang.IllegalStateException
        Ensures that the given member does not correspond to a internal member created by the instrumentation process. This would mean that the class is already instrumented.
        Parameters:
        member - name of the member to check
        owner - name of the class owning the member
        Throws:
        java.lang.IllegalStateException - thrown if the member has the same name than the instrumentation member

      • push

        public static void push​(org.objectweb.asm.MethodVisitor mv,
                        int value)
        Generates the instruction to push the given int value on the stack. Implementation taken from GeneratorAdapter.push(int).
        Parameters:
        mv - visitor to emit the instruction
        value - the value to be pushed on the stack.

      • classReaderFor

        public static org.objectweb.asm.ClassReader classReaderFor​(byte[] b)
        Creates a ClassReader instance for given bytes of class even if its version not yet supported by ASM.
        Parameters:
        b - bytes of class
        Returns:
        ClassReader