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Add UNREACHABLE also if the branchkmanger adds some blocks instructions

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This commit is contained in:
Volker Berlin 2019-03-03 21:33:09 +01:00
parent cd2f07733d
commit fb3ed8795e
2 changed files with 18 additions and 7 deletions
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9
src/de/inetsoftware/jwebassembly/module/JavaMethodWasmCodeBuilder.java
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@ -26,9 +26,9 @@ 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.AnyType;
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;
@ -81,11 +81,9 @@ class JavaMethodWasmCodeBuilder extends WasmCodeBuilder {
* 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
@ -542,7 +540,6 @@ class JavaMethodWasmCodeBuilder extends WasmCodeBuilder {
break;
}
addBlockInstruction( WasmBlockOperator.RETURN, type, codePos );
endWithReturn = true;
break;
case 178: // getstatic
ConstantRef ref = (ConstantRef)constantPool.get( byteCode.readUnsignedShort() );
@ -630,8 +627,8 @@ class JavaMethodWasmCodeBuilder extends WasmCodeBuilder {
}
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
if( hasReturn && !isEndsWithReturn() ) {
// if a method ends with a loop or block 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() );

16
src/de/inetsoftware/jwebassembly/module/WasmCodeBuilder.java
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@ -23,9 +23,10 @@ import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import de.inetsoftware.classparser.Member;
import de.inetsoftware.jwebassembly.module.WasmInstruction.Type;
import de.inetsoftware.jwebassembly.wasm.AnyType;
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;
@ -52,6 +53,19 @@ public abstract class WasmCodeBuilder {
return instructions;
}
/**
* Check if the last instruction is a return instruction
*
* @return true, if a return
*/
boolean isEndsWithReturn() {
WasmInstruction instr = instructions.get( instructions.size() - 1 );
if( instr.getType() == Type.Block ) {
return ((WasmBlockInstruction)instr).getOperation() == WasmBlockOperator.RETURN;
}
return false;
}
/**
* Initialize the code builder;
*