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Diffstat (limited to 'libjava/classpath/doc/vmintegration.texinfo')
| -rw-r--r-- | libjava/classpath/doc/vmintegration.texinfo | 89 |
1 files changed, 71 insertions, 18 deletions
diff --git a/libjava/classpath/doc/vmintegration.texinfo b/libjava/classpath/doc/vmintegration.texinfo index fa5f747ffea..e9f10460125 100644 --- a/libjava/classpath/doc/vmintegration.texinfo +++ b/libjava/classpath/doc/vmintegration.texinfo @@ -227,6 +227,7 @@ become operable. * java.lang.VMString:: * java.lang.VMThread:: * java.lang.VMInstrumentationImpl:: +* java.lang.VMMath:: @end menu @node java.lang.VMClass, java.lang.VMObject ,java.lang,java.lang @@ -684,17 +685,18 @@ having returned true, and is thus deprecated as a result. @end itemize @end itemize -@node java.lang.VMInstrumentationImpl,, java.lang.VMThread, java.lang +@node java.lang.VMInstrumentationImpl, java.lang.VMMath, java.lang.VMThread, java.lang @subsection @code{java.lang.VMInstrumentationImpl} The @code{java.lang.VMInstrumentationImpl} and -@code{java.lang.InstrumentationImpl} provides an implementation of the +@code{java.lang.InstrumentationImpl} classes provide an implementation of the @code{java.lang.instrument.Instrument} interface. This interface is for java 1.5 and is only in the generics branch. -A @code{InstrumentationImpl} object should be given to any agent -given in the command line (see the @code{java.lang.instrument} package -documentation). A VM has to implement the static native methods of the -@code{VMInstrumentationImpl} class. +A @code{InstrumentationImpl} object should be created by the VM when agents +are given in the command line (see the @code{java.lang.instrument} package +documentation). The VM has to set the static field +@code{VMClassLoader.instrumenter} to this object. The VM should implement the +static native methods of the @code{VMInstrumentationImpl} class. @itemize @bullet @item @code{isRedefineClassesSupported()} -- Returns true if the JVM supports @@ -707,21 +709,72 @@ by a specific class loader. @item @code{getObjectSize()} -- Gives the size of an object. @end itemize -When agents are defined, the VM has to call transformers of the -@code{InstrumentImpl} object each time a class is loaded, eg a call to -@code{VMClassLoader.defineClass}. The @code{InstrumentationImpl} class defines -a method that has to be called before reading a class file in the VM. +Instrumentation allows to modify the bytecode of a class before it gets read +by the VM. In GNU Classpath, the @code{ClassLoader.defineClass} method calls +the @code{VMClassLoader.defineClassWithTransformers} method which first checks +if @code{VMClassLoader.instrumenter} is @code{null}. If it's the case, it +directly calls @code{VMClassLoader.defineClass}. If it's not the case, the +method calls at first the @code{InstrumentationImpl.callTransformers} method, +which calls each transformer registered to the @code{InstrumentationImpl} +object and returns a new bytecode array. Then, it calls the +@code{VMClassLoader.defineClass} method with this new bytecode array. + +The second use of instrumentation is to redefine a class after it has been +loaded by the VM. This is done in the Java application by calling the +@code{Instrumentation.redefineClasses} method of the standard interface on +a @code{Instrumentation} object. The @code{InstrumentationImpl.redefineClasses} +method calls the @code{VMInstrumentationImpl.redefineClasses} native method +which must be implemented by the VM. The implementation should call the +@code{InstrumentationImpl.callTransformers} method. + +@node java.lang.VMMath, , java.lang.VMInstrumentationImpl, java.lang +@subsection @code{java.lang.VMMath} + +The @code{VMMath} class provides a series of native methods +for some of the mathematical functions present in @code{java.lang.Math}. +Classpath provides a default implementation of these which maps the +functions to those provided by @code{fdlibm}. VM implementors are welcome +to replace this with more efficent implementations, as long as the accuracy +contract of these methods, specified in @code{java.lang.Math}, is maintained. @itemize @bullet -@item @code{callTransformers} -- Calls each transformer registered to -the @code{InstrumentationImpl} object and returns a new bytecode file. +@item 1.0 +@itemize @bullet +@item @code{sin(double)} -- Returns the sine value for the given angle. +@item @code{cos(double)} -- Returns the cosine value for the given angle. +@item @code{tan(double)} -- Returns the tangent value for the given angle. +@item @code{asin(double)} -- Returns the arc sine value for the given angle. +@item @code{acos(double)} -- Returns the arc cosine value for the given angle. +@item @code{atan(double)} -- Returns the arc tangent value for the given angle. +@item @code{atan2(double,double)} -- Returns the arc tangent of the ratio of +the two arguments. +@item @code{exp(double)} -- Returns the exponent raised to the given power. +@item @code{log(double)} -- Returns the natural logarithm for the given value. +@item @code{sqrt(double)} -- Returns the square root of the value. +@item @code{pow(double,double)} -- Returns x to the power of y. +@item @code{IEEEremainder(double,double)} -- Returns the IEEE 754 remainder +for the two values. +@item @code{ceil(double)} -- Returns the nearest integer >= the value. +@item @code{floor(double)} -- Returns the nearest integer <= the value. +@item @code{rint(double)} -- Returns the nearest integer or the even one +if the distance between the two is equal. +@end itemize +@item 1.5 +@itemize @bullet +@item @code{cbrt(double)} -- Returns the cube root of the value. +@item @code{cosh(double)} -- Returns the hyperbolic cosine value for the given +angle. +@item @code{expm1(double)} -- Returns the exponent of the value minus one. +@item @code{hypot(double,double)} -- Returns the hypotenuse corresponding to +x and y. +@item @code{log10(double)} -- Returns the base 10 logarithm of the given value. +@item @code{log1p(double)} -- Returns the natural logarithm of the value plus +one. +@item @code{sinh(double)} -- Returns the hyperbolic sine value for the given +angle. +@item @code{tanh(double)} -- Returns the hyperbolic tangent value for the given angle. +@end itemize @end itemize - -No default implementation is provided in gnu classpath for the -@code{VMInstrumentationImpl} methods. A default implementation will perhaps -be written, but it might break the @code{ClassLoader/VMClassLoader} interface -for calling the @code{InstrumentationImpl.callTransformers} when a class byte -code is defined with @code{ClassLoader.defineClass}. @node gnu.classpath, java.util, java.lang, Classpath Hooks @section @code{gnu.classpath} |