/*
* Copyright 2018 - 2019 Volker Berlin (i-net software)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package de.inetsoftware.jwebassembly.module;
import java.io.IOException;
import java.util.List;
import javax.annotation.Nonnull;
import de.inetsoftware.classparser.Code;
import de.inetsoftware.classparser.CodeInputStream;
import de.inetsoftware.classparser.ConstantClass;
import de.inetsoftware.classparser.ConstantPool;
import de.inetsoftware.classparser.ConstantRef;
import de.inetsoftware.jwebassembly.WasmException;
import de.inetsoftware.jwebassembly.wasm.ArrayOperator;
import de.inetsoftware.jwebassembly.wasm.NumericOperator;
import de.inetsoftware.jwebassembly.wasm.AnyType;
import de.inetsoftware.jwebassembly.wasm.StructOperator;
import de.inetsoftware.jwebassembly.wasm.ValueType;
import de.inetsoftware.jwebassembly.wasm.WasmBlockOperator;
/**
* Convert Java Byte Code to a list of WasmInstruction.
*
* @author Volker Berlin
*/
class JavaMethodWasmCodeBuilder extends WasmCodeBuilder {
private BranchManger branchManager = new BranchManger( getInstructions() );
/**
* Build the wasm instructions
*
* @param code
* the Java method code
* @param hasReturn
* true, if the method has a return value; false, if it is void
* @throws WasmException
* if some Java code can't converted
*/
void buildCode( @Nonnull Code code, boolean hasReturn ) {
CodeInputStream byteCode = null;
try {
reset();
branchManager.reset( code );
byteCode = code.getByteCode();
writeCode( byteCode, code.getConstantPool(), hasReturn );
calculateVariables();
} catch( Exception ioex ) {
int lineNumber = byteCode == null ? -1 : byteCode.getLineNumber();
throw WasmException.create( ioex, lineNumber );
}
}
/**
* Write the byte code of a method.
*
* @param byteCode
* a stream of byte code
* @param constantPool
* the constant pool of the the current class
* @param hasReturn
* if the method has a return value
* @throws WasmException
* if some Java code can't converted
*/
private void writeCode( CodeInputStream byteCode, ConstantPool constantPool, boolean hasReturn ) throws WasmException {
boolean endWithReturn = false;
try {
while( byteCode.available() > 0 ) {
int codePos = byteCode.getCodePosition();
endWithReturn = false;
int op = byteCode.readUnsignedByte();
switch( op ) {
case 0: // nop
break;
case 1: // aconst_null
addStructInstruction( StructOperator.NULL, null, null, codePos );
break;
case 2: // iconst_m1
case 3: // iconst_0
case 4: // iconst_1
case 5: // iconst_2
case 6: // iconst_3
case 7: // iconst_4
case 8: // iconst_5
addConstInstruction( Integer.valueOf( op - 3 ), ValueType.i32, codePos );
break;
case 9: // lconst_0
case 10: // lconst_1
addConstInstruction( Long.valueOf( op - 9 ), ValueType.i64, codePos );
break;
case 11: // fconst_0
case 12: // fconst_1
case 13: // fconst_2
addConstInstruction( Float.valueOf( op - 11 ), ValueType.f32, codePos );
break;
case 14: // dconst_0
case 15: // dconst_1
addConstInstruction( Double.valueOf( op - 14 ), ValueType.f64, codePos );
break;
case 16: // bipush
addConstInstruction( Integer.valueOf( byteCode.readByte() ), ValueType.i32, codePos );
break;
case 17: // sipush
addConstInstruction( Integer.valueOf( byteCode.readShort() ), ValueType.i32, codePos );
break;
case 18: // ldc
addConstInstruction( (Number)constantPool.get( byteCode.readUnsignedByte() ), codePos );
break;
case 19: // ldc_w
case 20: // ldc2_w
addConstInstruction( (Number)constantPool.get( byteCode.readUnsignedShort() ), codePos );
break;
case 21: // iload
addLoadStoreInstruction( ValueType.i32, true, byteCode.readUnsignedByte(), codePos );
break;
case 22: // lload
addLoadStoreInstruction( ValueType.i64, true, byteCode.readUnsignedByte(), codePos );
break;
case 23: // fload
addLoadStoreInstruction( ValueType.f32, true, byteCode.readUnsignedByte(), codePos );
break;
case 24: // dload
addLoadStoreInstruction( ValueType.f64, true, byteCode.readUnsignedByte(), codePos );
break;
case 25: // aload
addLoadStoreInstruction( ValueType.anyref, true, byteCode.readUnsignedByte(), codePos );
break;
case 26: // iload_0
case 27: // iload_1
case 28: // iload_2
case 29: // iload_3
addLoadStoreInstruction( ValueType.i32, true, op - 26, codePos );
break;
case 30: // lload_0
case 31: // lload_1
case 32: // lload_2
case 33: // lload_3
addLoadStoreInstruction( ValueType.i64, true, op - 30, codePos );
break;
case 34: // fload_0
case 35: // fload_1
case 36: // fload_2
case 37: // fload_3
addLoadStoreInstruction( ValueType.f32, true, op - 34, codePos );
break;
case 38: // dload_0
case 39: // dload_1
case 40: // dload_2
case 41: // dload_3
addLoadStoreInstruction( ValueType.f64, true, op - 38, codePos );
break;
case 42: //aload_0
case 43: //aload_1
case 44: //aload_2
case 45: //aload_3
addLoadStoreInstruction( ValueType.anyref, true, op - 42, codePos );
break;
case 46: // iaload
addArrayInstruction( ArrayOperator.GET, ValueType.i32, codePos );
break;
case 47: // laload
addArrayInstruction( ArrayOperator.GET, ValueType.i64, codePos );
break;
case 48: // faload
addArrayInstruction( ArrayOperator.GET, ValueType.f32, codePos );
break;
case 49: // daload
addArrayInstruction( ArrayOperator.GET, ValueType.f64, codePos );
break;
case 50: // aaload
AnyType storeType = findPreviousPushInstructionPushValueType();
addArrayInstruction( ArrayOperator.GET, storeType, codePos );
break;
case 51: // baload
addArrayInstruction( ArrayOperator.GET, ValueType.i8, codePos );
break;
case 52: // caload
addArrayInstruction( ArrayOperator.GET, ValueType.i16, codePos );
break;
case 53: // saload
addArrayInstruction( ArrayOperator.GET, ValueType.i16, codePos );
break;
case 54: // istore
addLoadStoreInstruction( ValueType.i32, false, byteCode.readUnsignedByte(), codePos );
break;
case 55: // lstore
addLoadStoreInstruction( ValueType.i64, false, byteCode.readUnsignedByte(), codePos );
break;
case 56: // fstore
addLoadStoreInstruction( ValueType.f32, false, byteCode.readUnsignedByte(), codePos );
break;
case 57: // dstore
addLoadStoreInstruction( ValueType.f64, false, byteCode.readUnsignedByte(), codePos );
break;
case 58: // astore
addLoadStoreInstruction( ValueType.anyref, false, byteCode.readUnsignedByte(), codePos );
break;
case 59: // istore_0
case 60: // istore_1
case 61: // istore_2
case 62: // istore_3
addLoadStoreInstruction( ValueType.i32, false, op - 59, codePos );
break;
case 63: // lstore_0
case 64: // lstore_1
case 65: // lstore_2
case 66: // lstore_3
addLoadStoreInstruction( ValueType.i64, false, op - 63, codePos );
break;
case 67: // fstore_0
case 68: // fstore_1
case 69: // fstore_2
case 70: // fstore_3
addLoadStoreInstruction( ValueType.f32, false, op - 67, codePos );
break;
case 71: // dstore_0
case 72: // dstore_1
case 73: // dstore_2
case 74: // dstore_3
addLoadStoreInstruction( ValueType.f64, false, op - 71, codePos );
break;
case 75: // astore_0
case 76: // astore_1
case 77: // astore_2
case 78: // astore_3
storeType = findPreviousPushInstructionPushValueType();
addLoadStoreInstruction( storeType, false, op - 75, codePos );
break;
case 79: // iastore
addArrayInstruction( ArrayOperator.SET, ValueType.i32, codePos );
break;
case 80: // lastore
addArrayInstruction( ArrayOperator.SET, ValueType.i64, codePos );
break;
case 81: // fastore
addArrayInstruction( ArrayOperator.SET, ValueType.f32, codePos );
break;
case 82: // dastore
addArrayInstruction( ArrayOperator.SET, ValueType.f64, codePos );
break;
case 83: // aastore
storeType = findPreviousPushInstructionPushValueType();
addArrayInstruction( ArrayOperator.SET, storeType, codePos );
break;
case 84: // bastore
addArrayInstruction( ArrayOperator.SET, ValueType.i8, codePos );
break;
case 85: // castore
addArrayInstruction( ArrayOperator.SET, ValueType.i16, codePos );
break;
case 86: // sastore
addArrayInstruction( ArrayOperator.SET, ValueType.i16, codePos );
break;
case 87: // pop
case 88: // pop2
addBlockInstruction( WasmBlockOperator.DROP, null, codePos );
break;
case 89: // dup: duplicate the value on top of the stack
case 92: // dup2
storeType = findPreviousPushInstructionPushValueType();
addCallInstruction( new SyntheticFunctionName( "dup" + storeType, "local.get 0 local.get 0 return", storeType, null, storeType, storeType ), codePos );
break;
case 90: // dup_x1
case 91: // dup_x2
case 93: // dup2_x1
case 94: // dup2_x2
case 95: // swap
// can be do with functions with more as one return value in future WASM standard
throw new WasmException( "Stack duplicate is not supported in current WASM. try to save immediate values in a local variable: " + op, byteCode.getLineNumber() );
case 96: // iadd
addNumericInstruction( NumericOperator.add, ValueType.i32, codePos);
break;
case 97: // ladd
addNumericInstruction( NumericOperator.add, ValueType.i64, codePos );
break;
case 98: // fadd
addNumericInstruction( NumericOperator.add, ValueType.f32, codePos );
break;
case 99: // dadd
addNumericInstruction( NumericOperator.add, ValueType.f64, codePos );
break;
case 100: // isub
addNumericInstruction( NumericOperator.sub, ValueType.i32, codePos );
break;
case 101: // lsub
addNumericInstruction( NumericOperator.sub, ValueType.i64, codePos );
break;
case 102: // fsub
addNumericInstruction( NumericOperator.sub, ValueType.f32, codePos );
break;
case 103: // dsub
addNumericInstruction( NumericOperator.sub, ValueType.f64, codePos );
break;
case 104: // imul;
addNumericInstruction( NumericOperator.mul, ValueType.i32, codePos );
break;
case 105: // lmul
addNumericInstruction( NumericOperator.mul, ValueType.i64, codePos );
break;
case 106: // fmul
addNumericInstruction( NumericOperator.mul, ValueType.f32, codePos );
break;
case 107: // dmul
addNumericInstruction( NumericOperator.mul, ValueType.f64, codePos );
break;
case 108: // idiv
addNumericInstruction( NumericOperator.div, ValueType.i32, codePos );
break;
case 109: // ldiv
addNumericInstruction( NumericOperator.div, ValueType.i64, codePos );
break;
case 110: // fdiv
addNumericInstruction( NumericOperator.div, ValueType.f32, codePos );
break;
case 111: // ddiv
addNumericInstruction( NumericOperator.div, ValueType.f64, codePos );
break;
case 112: // irem
addNumericInstruction( NumericOperator.rem, ValueType.i32, codePos );
break;
case 113: // lrem
addNumericInstruction( NumericOperator.rem, ValueType.i64, codePos );
break;
case 114: // frem
case 115: // drem
//TODO can be implemented with a helper function like: (a - (long)(a / b) * (double)b)
throw new WasmException( "Modulo/Remainder for floating numbers is not supported in WASM. Use int or long data types." + op, byteCode.getLineNumber() );
case 116: // ineg
addConstInstruction( -1, ValueType.i32, codePos );
addNumericInstruction( NumericOperator.mul, ValueType.i32, codePos );
break;
case 117: // lneg
addConstInstruction( (long)-1, ValueType.i64, codePos );
addNumericInstruction( NumericOperator.mul, ValueType.i64, codePos );
break;
case 118: // fneg
addNumericInstruction( NumericOperator.neg, ValueType.f32, codePos );
break;
case 119: // dneg
addNumericInstruction( NumericOperator.neg, ValueType.f64, codePos );
break;
case 120: // ishl
addNumericInstruction( NumericOperator.shl, ValueType.i32, codePos );
break;
case 121: // lshl
addConvertInstruction( ValueTypeConvertion.i2l, codePos ); // the shift parameter must be of type long!!!
addNumericInstruction( NumericOperator.shl, ValueType.i64, codePos );
break;
case 122: // ishr
addNumericInstruction( NumericOperator.shr_s, ValueType.i32, codePos );
break;
case 123: // lshr
addConvertInstruction( ValueTypeConvertion.i2l, codePos ); // the shift parameter must be of type long!!!
addNumericInstruction( NumericOperator.shr_s, ValueType.i64, codePos );
break;
case 124: // iushr
addNumericInstruction( NumericOperator.shr_u, ValueType.i32, codePos );
break;
case 125: // lushr
addConvertInstruction( ValueTypeConvertion.i2l, codePos ); // the shift parameter must be of type long!!!
addNumericInstruction( NumericOperator.shr_u, ValueType.i64, codePos );
break;
case 126: // iand
addNumericInstruction( NumericOperator.and, ValueType.i32, codePos );
break;
case 127: // land
addNumericInstruction( NumericOperator.and, ValueType.i64, codePos );
break;
case 128: // ior
addNumericInstruction( NumericOperator.or, ValueType.i32, codePos );
break;
case 129: // lor
addNumericInstruction( NumericOperator.or, ValueType.i64, codePos );
break;
case 130: // ixor
addNumericInstruction( NumericOperator.xor, ValueType.i32, codePos );
break;
case 131: // lxor
addNumericInstruction( NumericOperator.xor, ValueType.i64, codePos );
break;
case 132: // iinc
int idx = byteCode.readUnsignedByte();
addLoadStoreInstruction( ValueType.i32, true, idx, codePos );
addConstInstruction( (int)byteCode.readByte(), ValueType.i32, codePos );
addNumericInstruction( NumericOperator.add, ValueType.i32, codePos);
addLoadStoreInstruction( ValueType.i32, false, idx, codePos );
break;
case 133: // i2l
addConvertInstruction( ValueTypeConvertion.i2l, codePos );
break;
case 134: // i2f
addConvertInstruction( ValueTypeConvertion.i2f, codePos );
break;
case 135: // i2d
addConvertInstruction( ValueTypeConvertion.i2d, codePos );
break;
case 136: // l2i
addConvertInstruction( ValueTypeConvertion.l2i, codePos );
break;
case 137: // l2f
addConvertInstruction( ValueTypeConvertion.l2f, codePos );
break;
case 138: // l2d
addConvertInstruction( ValueTypeConvertion.l2d, codePos );
break;
case 139: // f2i
addConvertInstruction( ValueTypeConvertion.f2i, codePos );
break;
case 140: // f2l
addConvertInstruction( ValueTypeConvertion.f2l, codePos );
break;
case 141: // f2d
addConvertInstruction( ValueTypeConvertion.f2d, codePos );
break;
case 142: // d2i
addConvertInstruction( ValueTypeConvertion.d2i, codePos );
break;
case 143: // d2l
addConvertInstruction( ValueTypeConvertion.d2l, codePos );
break;
case 144: // d2f
addConvertInstruction( ValueTypeConvertion.d2f, codePos );
break;
case 145: // i2b
addConvertInstruction( ValueTypeConvertion.i2b, codePos );
break;
case 146: // i2c
addConstInstruction( 0xFFFF, ValueType.i32, codePos );
addNumericInstruction( NumericOperator.and, ValueType.i32, codePos );
break;
case 147: // i2s
addConvertInstruction( ValueTypeConvertion.i2s, codePos );
break;
case 148: // lcmp
opCompare( ValueType.i64, byteCode, codePos );
break;
case 149: // fcmpl
case 150: // fcmpg
opCompare( ValueType.f32, byteCode, codePos );
break;
case 151: // dcmpl
case 152: // dcmpg
opCompare( ValueType.f64, byteCode, codePos );
break;
case 153: // ifeq
opIfCondition( NumericOperator.eq, byteCode, codePos );
break;
case 154: // ifne
opIfCondition( NumericOperator.ne, byteCode, codePos );
break;
case 155: // iflt
opIfCondition( NumericOperator.lt, byteCode, codePos );
break;
case 156: // ifge
opIfCondition( NumericOperator.ge, byteCode, codePos );
break;
case 157: // ifgt
opIfCondition( NumericOperator.gt, byteCode, codePos );
break;
case 158: // ifle
opIfCondition( NumericOperator.le, byteCode, codePos );
break;
case 159: // if_icmpeq
opIfCompareCondition( NumericOperator.eq, byteCode, codePos );
break;
case 160: // if_icmpne
opIfCompareCondition( NumericOperator.ne, byteCode, codePos );
break;
case 161: // if_icmplt
opIfCompareCondition( NumericOperator.lt, byteCode, codePos );
break;
case 162: // if_icmpge
opIfCompareCondition( NumericOperator.ge, byteCode, codePos );
break;
case 163: // if_icmpgt
opIfCompareCondition( NumericOperator.gt, byteCode, codePos );
break;
case 164: // if_icmple
opIfCompareCondition( NumericOperator.le, byteCode, codePos );
break;
case 165: // if_acmpeq
opIfCompareCondition( NumericOperator.ref_eq, byteCode, codePos );
break;
case 166: // if_acmpne
opIfCompareCondition( NumericOperator.ref_ne, byteCode, codePos );
break;
case 167: // goto
int offset = byteCode.readShort();
branchManager.addGotoOperator( codePos, offset, byteCode.getLineNumber() );
addNopInstruction( codePos ); // marker of the line number for the branch manager
break;
//TODO case 168: // jsr
//TODO case 169: // ret
case 170: // tableswitch
case 171: // lookupswitch
writeSwitchCode( byteCode, op == 171 );
break;
case 172: // ireturn
case 173: // lreturn
case 174: // freturn
case 175: // dreturn
case 176: // areturn
case 177: // return void
ValueType type = null;
switch ( op ) {
case 172: // ireturn
type = ValueType.i32;
break;
case 173: // lreturn
type = ValueType.i64;
break;
case 174: // freturn
type = ValueType.f32;
break;
case 175: // dreturn
type = ValueType.f64;
break;
case 176: // areturn
type = ValueType.anyref;
break;
}
addBlockInstruction( WasmBlockOperator.RETURN, type, codePos );
endWithReturn = true;
break;
case 178: // getstatic
ConstantRef ref = (ConstantRef)constantPool.get( byteCode.readUnsignedShort() );
addGlobalInstruction( true, ref, codePos );
break;
case 179: // putstatic
ref = (ConstantRef)constantPool.get( byteCode.readUnsignedShort() );
addGlobalInstruction( false, ref, codePos );
break;
case 180: // getfield
ref = (ConstantRef)constantPool.get( byteCode.readUnsignedShort() );
addStructInstruction( StructOperator.GET, ref.getClassName(), ref.getName(), codePos );
break;
case 181: // putfield
ref = (ConstantRef)constantPool.get( byteCode.readUnsignedShort() );
addStructInstruction( StructOperator.SET, ref.getClassName(), ref.getName(), codePos );
break;
//TODO case 182: // invokevirtual
case 183: // invokespecial, invoke a constructor
case 184: // invokestatic
idx = byteCode.readUnsignedShort();
ref = (ConstantRef)constantPool.get( idx );
addCallInstruction( new FunctionName( ref ), codePos );
break;
//TODO case 185: // invokeinterface
//TODO case 186: // invokedynamic
case 187: // new
String name = ((ConstantClass)constantPool.get( byteCode.readUnsignedShort() )).getName();
addStructInstruction( StructOperator.NEW_DEFAULT, name, null, codePos );
break;
case 188: // newarray
int typeValue = byteCode.readByte();
switch( typeValue ) {
case 4: // boolean
case 5: // char
type = ValueType.i32;
break;
case 6: //float
type = ValueType.f32;
break;
case 7: //double
type = ValueType.f64;
break;
case 8: //byte
case 9: //short
case 10: //int
type = ValueType.i32;
break;
case 11: //long
type = ValueType.i64;
break;
default:
throw new WasmException( "Invalid Java byte code newarray: " + typeValue, byteCode.getLineNumber() );
}
addArrayInstruction( ArrayOperator.NEW, type, codePos );
break;
case 189: // anewarray
name = ((ConstantClass)constantPool.get( byteCode.readUnsignedShort() )).getName();
type = ValueType.anyref; //TODO we need to use the right type from name
addArrayInstruction( ArrayOperator.NEW, type, codePos );
break;
case 190: // arraylength
addArrayInstruction( ArrayOperator.LENGTH, ValueType.i32, codePos );
break;
//TODO case 191: // athrow
//TODO case 192: // checkcast
//TODO case 193: // instanceof
//TODO case 194: // monitorenter
//TODO case 195: // monitorexit
//TODO case 196: // wide
//TODO case 197: // multianewarray
case 198: // ifnull
opIfCompareCondition( NumericOperator.ifnull, byteCode, codePos );
break;
case 199: // ifnonnull
opIfCompareCondition( NumericOperator.ifnonnull, byteCode, codePos );
break;
//TODO case 200: // goto_w
//TODO case 201: // jsr_w
default:
throw new WasmException( "Unimplemented Java byte code operation: " + op, byteCode.getLineNumber() );
}
}
branchManager.calculate();
branchManager.handle( byteCode ); // add branch operations
if( !endWithReturn && hasReturn ) {
// if a method ends with a loop without a break then code after the loop is no reachable
// Java does not need a return byte code in this case
// But WebAssembly need the dead code to validate
addBlockInstruction( WasmBlockOperator.UNREACHABLE, null, byteCode.getCodePosition() );
}
} catch( WasmException ex ) {
throw ex;
} catch( Exception ex ) {
throw WasmException.create( ex, byteCode.getLineNumber() );
}
}
/**
* Write the both switch operation codes
*
* @param byteCode
* the current stream with a position after the operation code
* @param isLookupSwitch
* true, if the operation was a loopupswitch; false, if the operation was a tableswitch
* @throws IOException
* if any I/O error occur
*/
private void writeSwitchCode( CodeInputStream byteCode, boolean isLookupSwitch ) throws IOException {
int lineNumber = byteCode.getLineNumber();
int codePos = byteCode.getCodePosition();
int startPosition = codePos;
int padding = startPosition % 4;
if( padding > 0 ) {
byteCode.skip( 4 - padding );
}
startPosition--;
int switchValuestartPosition = findPreviousPushInstructionCodePosition();
int defaultPosition = startPosition + byteCode.readInt();
int[] keys;
int[] positions;
if( isLookupSwitch ) { // lookupswitch
int count = byteCode.readInt();
keys = new int[count];
positions = new int[count];
for( int i = 0; i < count; i++ ) {
keys[i] = byteCode.readInt();
positions[i] = startPosition + byteCode.readInt();
}
int tempI32 = -1;
int block = 0;
int defaultBlock = -1;
int currentPos = -1;
addLoadStoreInstruction( ValueType.i32, false, tempI32, codePos );
do {
int nextPos = findNext( currentPos, positions );
if( nextPos == currentPos ) {
break;
}
currentPos = nextPos;
if( defaultBlock < 0 ) {
if( defaultPosition <= currentPos ) {
defaultBlock = block;
if( defaultPosition < currentPos ) {
block++;
}
}
}
for( int i = 0; i < positions.length; i++ ) {
if( positions[i] == currentPos ) {
addLoadStoreInstruction( ValueType.i32, true, tempI32, codePos );
addConstInstruction( keys[i], ValueType.i32, codePos );
addNumericInstruction( NumericOperator.eq, ValueType.i32, codePos );
addBlockInstruction( WasmBlockOperator.BR_IF, block, codePos );
}
}
block++;
} while( true );
if( defaultBlock < 0 ) {
defaultBlock = block;
}
addBlockInstruction( WasmBlockOperator.BR, defaultBlock, codePos );
} else {
int low = byteCode.readInt();
keys = null;
int count = byteCode.readInt() - low + 1;
positions = new int[count];
for( int i = 0; i < count; i++ ) {
positions[i] = startPosition + byteCode.readInt();
}
if( low != 0 ) { // the br_table starts ever with the value 0. That we need to subtract the start value if it different
addConstInstruction( low, ValueType.i32, codePos );
addNumericInstruction( NumericOperator.sub, ValueType.i32, codePos );
}
}
branchManager.addSwitchOperator( switchValuestartPosition, 0, lineNumber, keys, positions, defaultPosition );
}
/**
* We need one value from the stack inside of a block. We need to find the WasmInstruction on which the block can
* start. If this a function call or numeric expression this can be complex to find the right point.
*
* @return the code position that push the last instruction
*/
@Nonnull
private int findPreviousPushInstructionCodePosition() {
int valueCount = 0;
List<WasmInstruction> instructions = getInstructions();
for( int i = instructions.size() - 1; i >= 0; i-- ) {
WasmInstruction instr = instructions.get( i );
AnyType valueType = instr.getPushValueType();
if( valueType != null ) {
valueCount++;
}
valueCount -= instr.getPopCount();
if( valueCount == 1 ) {
return instr.getCodePosition();
}
}
throw new WasmException( "Start position not found", -1 ); // should never occur
}
/**
* We need the value type from the stack.
*
* @return the type of the last push value
*/
@Nonnull
private AnyType findPreviousPushInstructionPushValueType() {
int valueCount = 0;
List<WasmInstruction> instructions = getInstructions();
for( int i = instructions.size() - 1; i >= 0; i-- ) {
WasmInstruction instr = instructions.get( i );
AnyType valueType = instr.getPushValueType();
if( valueType != null ) {
if( ++valueCount == 1 ) {
return valueType;
}
}
valueCount -= instr.getPopCount();
}
throw new WasmException( "Push Value not found", -1 ); // should never occur
}
/**
* Find the next higher value.
*
* @param current
* the current value
* @param values
* the unordered list of values
* @return the next value or current value if not found.
*/
private static int findNext( int current, int[] values ) {
boolean find = false;
int next = Integer.MAX_VALUE;
for( int val : values ) {
if( val > current && val <= next ) {
next = val;
find = true;
}
}
return find ? next : current;
}
/**
* Handle the if<condition> of the Java byte code. This Java instruction compare the first stack value with value 0.
* Important: In the Java IF expression the condition for the jump to the else block is saved. In WebAssembler we
* need to use condition for the if block. The caller of the method must already negate this
* @param compareOp
* The condition for the continue of a loop.
* @param byteCode
* current byte code stream to read the target offset.
* @param codePos
* the code position/offset in the Java method
*
* @throws IOException
* if any I/O errors occur.
*/
private void opIfCondition( NumericOperator compareOp, CodeInputStream byteCode, int codePos ) throws IOException {
addConstInstruction( 0, ValueType.i32, codePos );
opIfCompareCondition( compareOp, byteCode, codePos );
}
/**
* Handle the if<condition> of the Java byte code. This Java instruction compare 2 values from stack.
* Important: In the Java IF expression the condition for the jump to the else block is saved. In WebAssembler we need to use
* condition for the if block. The caller of the method must already negate this.
* @param compareOp
* The condition for the continue of a loop.
* @param byteCode
* current byte code stream to read the target offset.
* @param codePos
* the code position/offset in the Java method
*
* @throws IOException
* if any I/O errors occur.
*/
private void opIfCompareCondition( NumericOperator compareOp, CodeInputStream byteCode, int codePos ) throws IOException {
int offset = byteCode.readShort();
WasmNumericInstruction compare = new WasmNumericInstruction( compareOp, ValueType.i32, codePos );
branchManager.addIfOperator( codePos, offset, byteCode.getLineNumber(), compare );
getInstructions().add( compare );
}
/**
* Handle the different compare operator. The compare operator returns the integer values -1, 0 or 1. There is no
* equivalent in WebAssembly. That we need to read the next operation to find an equivalent.
*
* @param valueType
* the value type of the compared
* @param byteCode
* current byte code stream to read the next operation.
* @param codePos
* the code position/offset in the Java method
* @throws IOException
* if any I/O errors occur.
*/
private void opCompare( ValueType valueType, CodeInputStream byteCode, int codePos ) throws IOException {
codePos = byteCode.getCodePosition();
NumericOperator numOp;
int nextOp = byteCode.read();
switch( nextOp ){
case 153: // ifeq
numOp = NumericOperator.eq;
break;
case 154: // ifne
numOp = NumericOperator.ne;
break;
case 155: // iflt
numOp = NumericOperator.lt;
break;
case 156: // ifge
numOp = NumericOperator.ge;
break;
case 157: // ifgt
numOp = NumericOperator.gt;
break;
case 158: // ifle
numOp = NumericOperator.le;
break;
default:
throw new WasmException( "Unexpected compare sub operation: " + nextOp, -1 );
}
int offset = byteCode.readShort();
WasmNumericInstruction compare = new WasmNumericInstruction( numOp, valueType, codePos );
branchManager.addIfOperator( codePos, offset, byteCode.getLineNumber(), compare );
getInstructions().add( compare );
}
}