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Make readField and readMethod + fix readUTFB
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Vincent Rasquier committed Dec 14, 2017
1 parent d16802a commit 1216a98
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27 changes: 27 additions & 0 deletions README.md
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@@ -0,0 +1,27 @@
# ASM

[IN PROGRESS]

This repository is a Golang port of the famous ASM java library for JVM bytecode reading and manipulation.
http://asm.ow2.org/. You can find the original source code at this link : https://gitlab.ow2.org/asm/asm.

## Goal
There are multiple goals for this port. The first one is comparing performance between the actual Java implementation and with this port.
Second reason could be to provide different tools for JVM manipulation through Golang, as, for example, a simple conversion of JVM Bytecode to Go.

## Progress

| CLASS | PROGRESS % |
| ClassReader | 60% |
| ClassVisitor | 100% |
| MethodVisitor | 100% |
| FieldVisitor | 100% |
| ModuleVisitor | 100% |
| AnnotationVisitor | 100% |
| Attribute | ? |
| Context | ? |
| Label | ? |
| TypeReference | ? |
| Opcodes | ? |
| Symbol | ? |
| TypePath | 0% |
317 changes: 311 additions & 6 deletions asm/classreader.go
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Original file line number Diff line number Diff line change
Expand Up @@ -461,20 +461,322 @@ func (c ClassReader) readModule(classVisitor ClassVisitor, context *Context, mod
}

func (c ClassReader) readField(classVisitor ClassVisitor, context *Context, fieldInfoOffset int) int {
//TODO
return 0
charBuffer := context.charBuffer
currentOffset := fieldInfoOffset
accessFlags := c.readUnsignedShort(currentOffset)
name := c.readUTF8(currentOffset+2, charBuffer)
descriptor := c.readUTF8(currentOffset+4, charBuffer)
currentOffset += 6

var constantValue interface{}
var signature string

runtimeVisibleAnnotationsOffset := 0
runtimeInvisibleAnnotationsOffset := 0
runtimeVisibleTypeAnnotationsOffset := 0
runtimeInvisibleTypeAnnotationsOffset := 0
var attributes *Attribute

attributesCount := c.readUnsignedShort(currentOffset)
currentOffset += 2

for attributesCount > 0 {
attributeName := c.readUTF8(currentOffset, charBuffer)
attributeLength := c.readInt(currentOffset + 2)
currentOffset += 6

switch attributeName {
case "ConstantValue":
constantvalueIndex := c.readUnsignedShort(currentOffset)
if constantvalueIndex != 0 {
constantValue, _ = c.readConst(constantvalueIndex, charBuffer)
}
break
case "Signature":
signature = c.readUTF8(currentOffset, charBuffer)
break
case "Deprecated":
accessFlags |= opcodes.ACC_DEPRECATED
break
case "Synthetic":
accessFlags |= opcodes.ACC_SYNTHETIC
break
case "RuntimeVisibleAnnotations":
runtimeVisibleAnnotationsOffset = currentOffset
break
case "RuntimeVisibleTypeAnnotations":
runtimeVisibleTypeAnnotationsOffset = currentOffset
break
case "RuntimeInvisibleAnnotations":
runtimeInvisibleAnnotationsOffset = currentOffset
break
case "RuntimeInvisibleTypeAnnotations":
runtimeInvisibleTypeAnnotationsOffset = currentOffset
break
default:
attribute := c.readAttribute(context.attributePrototypes, attributeName, currentOffset, attributeLength, charBuffer, -1, nil)
attribute.nextAttribute = attributes
attributes = attribute
break
}
currentOffset += attributeLength
attributesCount--
}

fieldVisitor := classVisitor.VisitField(accessFlags, name, descriptor, signature, constantValue)
if fieldVisitor == nil {
return currentOffset
}

if runtimeVisibleAnnotationsOffset != 0 {
numAnnotations := c.readUnsignedShort(runtimeVisibleAnnotationsOffset)
currentAnnotationOffset := runtimeVisibleAnnotationsOffset + 2
for numAnnotations > 0 {
annotationDescriptor := c.readUTF8(currentAnnotationOffset, charBuffer)
currentAnnotationOffset += 2
currentAnnotationOffset = c.readElementValues(fieldVisitor.VisitAnnotation(annotationDescriptor, true), currentAnnotationOffset, true, charBuffer)
numAnnotations--
}
}

if runtimeInvisibleAnnotationsOffset != 0 {
numAnnotations := c.readUnsignedShort(runtimeInvisibleAnnotationsOffset)
currentAnnotationOffset := runtimeInvisibleAnnotationsOffset + 2
for numAnnotations > 0 {
annotationDescriptor := c.readUTF8(currentAnnotationOffset, charBuffer)
currentAnnotationOffset += 2
currentAnnotationOffset = c.readElementValues(fieldVisitor.VisitAnnotation(annotationDescriptor, false), currentAnnotationOffset, true, charBuffer)
numAnnotations--
}
}

if runtimeVisibleTypeAnnotationsOffset != 0 {
numAnnotations := c.readUnsignedShort(runtimeVisibleTypeAnnotationsOffset)
currentAnnotationOffset := runtimeVisibleTypeAnnotationsOffset + 2
for numAnnotations > 0 {
currentAnnotationOffset = c.readTypeAnnotationTarget(context, currentAnnotationOffset)
annotationDescriptor := c.readUTF8(currentAnnotationOffset, charBuffer)
currentAnnotationOffset += 2
annotationVisitor := fieldVisitor.VisitTypeAnnotation(context.currentTypeAnnotationTarget, context.currentTypeAnnotationTargetPath, annotationDescriptor, true)
currentAnnotationOffset = c.readElementValues(annotationVisitor, currentAnnotationOffset, true, charBuffer)
numAnnotations--
}
}

if runtimeInvisibleTypeAnnotationsOffset != 0 {
numAnnotations := c.readUnsignedShort(runtimeInvisibleTypeAnnotationsOffset)
currentAnnotationOffset := runtimeInvisibleTypeAnnotationsOffset + 2
for numAnnotations > 0 {
currentAnnotationOffset = c.readTypeAnnotationTarget(context, currentAnnotationOffset)
annotationDescriptor := c.readUTF8(currentAnnotationOffset, charBuffer)
currentAnnotationOffset += 2
annotationVisitor := fieldVisitor.VisitTypeAnnotation(context.currentTypeAnnotationTarget, context.currentTypeAnnotationTargetPath, annotationDescriptor, false)
currentAnnotationOffset = c.readElementValues(annotationVisitor, currentAnnotationOffset, true, charBuffer)
numAnnotations--
}
}

for attributes != nil {
nextAttribute := attributes.nextAttribute
attributes.nextAttribute = nil
fieldVisitor.VisitAttribute(attributes)
attributes = nextAttribute
}

fieldVisitor.VisitEnd()
return currentOffset
}

func (c ClassReader) readMethod(classVisitor ClassVisitor, context *Context, methodInfoOffset int) int {
//TODO
return 0
charBuffer := context.charBuffer
currentOffset := methodInfoOffset
context.currentMethodAccessFlags = c.readUnsignedShort(currentOffset)
context.currentMethodName = c.readUTF8(currentOffset+2, charBuffer)
context.currentMethodDescriptor = c.readUTF8(currentOffset+4, charBuffer)
currentOffset += 6

codeOffset := 0
exceptionsOffset := 0
var exceptions []string
signature := 0
runtimeVisibleAnnotationsOffset := 0
runtimeInvisibleAnnotationsOffset := 0
runtimeVisibleParameterAnnotationsOffset := 0
runtimeInvisibleParameterAnnotationsOffset := 0
runtimeVisibleTypeAnnotationsOffset := 0
runtimeInvisibleTypeAnnotationsOffset := 0
annotationDefaultOffset := 0
methodParametersOffset := 0
var attributes *Attribute

attributesCount := c.readUnsignedShort(currentOffset)
currentOffset += 2
for attributesCount > 0 {
attributeName := c.readUTF8(currentOffset, charBuffer)
attributeLength := c.readInt(currentOffset + 2)
currentOffset += 6

switch attributeName {
case "Code":
codeOffset = currentOffset
break
case "Exceptions":
exceptionsOffset = currentOffset
exceptions = make([]string, c.readUnsignedShort(exceptionsOffset))
currentExceptionOffset := exceptionsOffset + 2
for i := 0; i < len(exceptions); i++ {
exceptions[i] = c.readClass(currentExceptionOffset, charBuffer)
currentExceptionOffset += 2
}
break
case "Signature":
signature = c.readUnsignedShort(currentOffset)
break
case "Deprecated":
context.currentMethodAccessFlags |= opcodes.ACC_DEPRECATED
break
case "RuntimeVisibleAnnotations":
runtimeVisibleAnnotationsOffset = currentOffset
break
case "RuntimeVisibleTypeAnnotations":
runtimeVisibleTypeAnnotationsOffset = currentOffset
break
case "AnnotationDefault":
annotationDefaultOffset = currentOffset
break
case "Synthetic":
context.currentMethodAccessFlags |= opcodes.ACC_SYNTHETIC
break
case "RuntimeInvisibleAnnotations":
runtimeInvisibleAnnotationsOffset = currentOffset
break
case "RuntimeInvisibleTypeAnnotations":
runtimeInvisibleTypeAnnotationsOffset = currentOffset
break
case "RuntimeVisibleParameterAnnotations":
runtimeVisibleParameterAnnotationsOffset = currentOffset
break
case "RuntimeInvisibleParameterAnnotations":
runtimeInvisibleParameterAnnotationsOffset = currentOffset
break
case "MethodParameters":
methodParametersOffset = currentOffset
break
default:
attribute := c.readAttribute(context.attributePrototypes, attributeName, currentOffset, attributeLength, charBuffer, -1, nil)
attribute.nextAttribute = attributes
attributes = attribute
break
}
currentOffset += attributeLength
attributesCount--
}

var sig string
if signature != 0 {
sig = c.readUTF(signature, charBuffer)
}
methodVisitor := classVisitor.VisitMethod(context.currentMethodAccessFlags, context.currentMethodName, context.currentMethodDescriptor, sig, exceptions)
if methodVisitor == nil {
return currentOffset
}

/* MethodWriter instanceof ? */

if methodParametersOffset != 0 {
parametersCount := c.readByte(methodParametersOffset)
currentParameterOffset := methodParametersOffset + 1
for parametersCount > 0 {
methodVisitor.VisitParameter(c.readUTF8(currentParameterOffset, charBuffer), c.readUnsignedShort(currentParameterOffset+2))
currentParameterOffset += 4
parametersCount--
}
}

if annotationDefaultOffset != 0 {
annotationVisitor := methodVisitor.VisitAnnotationDefault()
c.readElementValue(annotationVisitor, annotationDefaultOffset, "", charBuffer)
if annotationVisitor != nil {
annotationVisitor.VisitEnd()
}
}

if runtimeVisibleAnnotationsOffset != 0 {
numAnnotations := c.readUnsignedShort(runtimeVisibleAnnotationsOffset)
currentAnnotationOffset := runtimeVisibleAnnotationsOffset + 2
for numAnnotations > 0 {
annotationDescriptor := c.readUTF8(currentAnnotationOffset, charBuffer)
currentAnnotationOffset += 2
currentAnnotationOffset = c.readElementValues(methodVisitor.VisitAnnotation(annotationDescriptor, true), currentAnnotationOffset, true, charBuffer)
numAnnotations--
}
}

if runtimeInvisibleAnnotationsOffset != 0 {
numAnnotations := c.readUnsignedShort(runtimeInvisibleAnnotationsOffset)
currentAnnotationOffset := runtimeInvisibleAnnotationsOffset + 2
for numAnnotations > 0 {
annotationDescriptor := c.readUTF8(currentAnnotationOffset, charBuffer)
currentAnnotationOffset += 2
currentAnnotationOffset = c.readElementValues(methodVisitor.VisitAnnotation(annotationDescriptor, false), currentAnnotationOffset, true, charBuffer)
numAnnotations--
}
}

if runtimeVisibleTypeAnnotationsOffset != 0 {
numAnnotations := c.readUnsignedShort(runtimeVisibleTypeAnnotationsOffset)
currentAnnotationOffset := runtimeVisibleTypeAnnotationsOffset + 2
for numAnnotations > 0 {
currentAnnotationOffset = c.readTypeAnnotationTarget(context, currentAnnotationOffset)
annotationDescriptor := c.readUTF8(currentAnnotationOffset, charBuffer)
currentAnnotationOffset += 2
annotationVisitor := methodVisitor.VisitTypeAnnotation(context.currentTypeAnnotationTarget, context.currentTypeAnnotationTargetPath, annotationDescriptor, true)
currentAnnotationOffset = c.readElementValues(annotationVisitor, currentAnnotationOffset, true, charBuffer)
numAnnotations--
}
}

if runtimeInvisibleTypeAnnotationsOffset != 0 {
numAnnotations := c.readUnsignedShort(runtimeInvisibleTypeAnnotationsOffset)
currentAnnotationOffset := runtimeInvisibleTypeAnnotationsOffset + 2
for numAnnotations > 0 {
currentAnnotationOffset = c.readTypeAnnotationTarget(context, currentAnnotationOffset)
annotationDescriptor := c.readUTF8(currentAnnotationOffset, charBuffer)
currentAnnotationOffset += 2
annotationVisitor := methodVisitor.VisitTypeAnnotation(context.currentTypeAnnotationTarget, context.currentTypeAnnotationTargetPath, annotationDescriptor, false)
currentAnnotationOffset = c.readElementValues(annotationVisitor, currentAnnotationOffset, true, charBuffer)
}
}

if runtimeVisibleParameterAnnotationsOffset != 0 {
c.readParameterAnnotations(methodVisitor, context, runtimeVisibleParameterAnnotationsOffset, true)
}

if runtimeInvisibleParameterAnnotationsOffset != 0 {
c.readParameterAnnotations(methodVisitor, context, runtimeInvisibleParameterAnnotationsOffset, false)
}

for attributes != nil {
nextAttribute := attributes.nextAttribute
attributes.nextAttribute = nil
methodVisitor.VisitAttribute(attributes)
attributes = nextAttribute
}

if codeOffset != 0 {
methodVisitor.VisitCode()
c.readCode(methodVisitor, context, codeOffset)
}

methodVisitor.VisitEnd()
return currentOffset
}

// ----------------------------------------------------------------------------------------------
// Methods to parse a Code attribute
// ----------------------------------------------------------------------------------------------

func (c ClassReader) readCode(methodVisitor MethodVisitor, contexnt *Context, codeOffset int) {
func (c ClassReader) readCode(methodVisitor MethodVisitor, context *Context, codeOffset int) {
//TODO
}

Expand Down Expand Up @@ -673,10 +975,13 @@ func (c ClassReader) readUTFB(utfOffset int, utfLength int, charBuffer []rune) s
d := ((currentByte & 0xF) << 12) + ((b[currentOffset] & 0x3F) << 6)
currentOffset++
charBuffer[strLength] = rune((d + (b[currentOffset] & 0x3F)))
currentOffset++
strLength++
}
}
return string(charBuffer)
str := make([]rune, strLength)
copy(str, charBuffer[0:strLength])
return string(str)
}

func (c ClassReader) readStringish(offset int, charBuffer []rune) string {
Expand Down
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