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GP-4967: Corrected issues related to emulator cached block instruction

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re-use.
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Dan 2024-09-25 09:57:49 -04:00 committed by ghidra1
parent 025cc9f702
commit e8c28c2a84
2 changed files with 31 additions and 14 deletions
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39
Ghidra/Framework/Emulation/src/main/java/ghidra/pcode/emu/SleighInstructionDecoder.java
View File

@ -15,6 +15,8 @@
*/
package ghidra.pcode.emu;
import java.util.Objects;
import ghidra.app.util.PseudoInstruction;
import ghidra.pcode.emulate.InstructionDecodeException;
import ghidra.pcode.exec.DecodePcodeExecutionException;
@ -73,14 +75,18 @@ public class SleighInstructionDecoder implements InstructionDecoder {
Disassembler.getDisassembler(language, addrFactory, TaskMonitor.DUMMY, listener);
}
@Override
public Instruction decodeInstruction(Address address, RegisterValue context) {
lastMsg = DEFAULT_ERROR;
if (block != null &&
(instruction = (PseudoInstruction) block.getInstructionAt(address)) != null) {
return instruction;
protected boolean useCachedInstruction(Address address, RegisterValue context) {
if (block == null) {
return false;
}
/*
// Always use instruction within last block decoded assuming we flowed from another
// instruction within the same block. The block should be null is starting a new flow.
instruction = (PseudoInstruction) block.getInstructionAt(address);
return instruction != null;
}
protected void parseNewBlock(Address address, RegisterValue context) {
/**
* Parse as few instructions as possible. If more are returned, it's because they form a
* parallel instruction group. In that case, I should not have to worry self-modifying code
* within that group, so no need to re-disassemble after each is executed.
@ -91,17 +97,28 @@ public class SleighInstructionDecoder implements InstructionDecoder {
throw new DecodePcodeExecutionException(lastMsg, address);
}
instruction = (PseudoInstruction) block.getInstructionAt(address);
}
@Override
public Instruction decodeInstruction(Address address, RegisterValue context) {
lastMsg = DEFAULT_ERROR;
if (!useCachedInstruction(address, context)) {
parseNewBlock(address, context);
}
lengthWithDelays = computeLength();
return instruction;
}
@Override
public void branched(Address address) {
/*
* This shouldn't happen in the middle of a parallel instruction group, but in case the
* group modifies itself and jumps back to itself, this will ensure it is re-disassembled.
/**
* There may be internal branching within a decoded block. Those shouldn't clear the block.
* However, if the cached instruction's context does not match the desired one, assume we're
* starting a new block. That check will have to wait for the decode call, though.
*/
block = null;
if (block.getInstructionAt(address) == null) {
block = null;
}
}
/**

2
Ghidra/Framework/Emulation/src/main/java/ghidra/pcode/exec/AbstractBytesPcodeExecutorStatePiece.java
View File

@ -66,7 +66,7 @@ public abstract class AbstractBytesPcodeExecutorStatePiece<S extends BytesPcodeE
@Override
public Memory getMemory() {
throw new UnsupportedOperationException();
return null;
}
@Override