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Code Issues Releases Wiki Activity

GP-24_emteere_PcodeDisassemblyEmulationError refactor from code review

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This commit is contained in:
emteere 2020-07-14 16:03:34 -04:00
parent 27f9b750db
commit 9255d6ba0b
3 changed files with 112 additions and 27 deletions
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4
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/disassemble/Disassembler.java
View file

@ -50,6 +50,8 @@ import ghidra.util.task.TaskMonitor;
*/
public class Disassembler implements DisassemblerConflictHandler {
private static final int DISASSEMBLE_MEMORY_CACHE_SIZE = 8;
/**
* <code>MARK_BAD_INSTRUCTION_PROPERTY</code> Program Disassembler property
* enables marking of instruction disassembly errors. Boolean property is defined
@ -920,7 +922,7 @@ public class Disassembler implements DisassemblerConflictHandler {
disassemblerContext.flowToAddress(addr);
MemBuffer instrMemBuffer = new WrappedMemBuffer(blockMemBuffer,
MemBuffer instrMemBuffer = new WrappedMemBuffer(blockMemBuffer, DISASSEMBLE_MEMORY_CACHE_SIZE,
(int) addr.subtract(blockMemBuffer.getAddress()));
adjustPreParseContext(instrMemBuffer);

61
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/mem/WrappedMemBuffer.java
View file

@ -29,7 +29,7 @@ public class WrappedMemBuffer implements MemBuffer {
private int baseOffset;
private Address address;
private static final int DEFAULT_BUFSIZE = 10;
private static final int DEFAULT_BUFSIZE = 0; // default no buffer
private byte[] buffer;
private int subBufferIndex = 0;
@ -80,12 +80,12 @@ public class WrappedMemBuffer implements MemBuffer {
// already set, changing position
if (minOffset <= maxOffset) {
long diff = offset - baseOffset;
if (diff >= minOffset && diff < (maxOffset - threshold)) {
long curOffset = offset - baseOffset; // convert the new offset into an offset based on current offset
if (curOffset >= minOffset && curOffset < (maxOffset - threshold)) {
baseOffset = offset;
minOffset -= (int) diff;
maxOffset -= (int) diff;
subBufferIndex += diff;
minOffset -= (int) curOffset;
maxOffset -= (int) curOffset;
subBufferIndex += curOffset;
return;
}
}
@ -128,6 +128,35 @@ public class WrappedMemBuffer implements MemBuffer {
return buffer[subBufferIndex + offset];
}
fillBuffer(offset);
return buffer[0];
}
@Override
public int getBytes(byte[] b, int offset) {
try {
// if there is a buffer, and the number of bytes requested will fit in the buffer
if (buffer.length > 0 && b.length <= buffer.length) {
// bytes not in buffer
if (offset < minOffset || (b.length + offset - 1) > maxOffset) {
fillBuffer(offset);
}
// bytes are contained in the buffer
if (offset >= minOffset && (b.length + offset - 1) <= maxOffset) {
System.arraycopy(buffer, subBufferIndex + offset, b, 0, b.length);
return b.length;
}
}
// grab from wrapped buffer, too many bytes, or no buffer
return memBuffer.getBytes(b, computeOffset(offset));
} catch (MemoryAccessException e) {
return 0;
}
}
private void fillBuffer(int offset) throws MemoryAccessException {
// fill the buffer
int nRead = memBuffer.getBytes(buffer, computeOffset(offset));
@ -138,26 +167,6 @@ public class WrappedMemBuffer implements MemBuffer {
if (nRead == 0) {
throw new MemoryAccessException();
}
return buffer[0];
}
@Override
public int getBytes(byte[] b, int offset) {
if (buffer.length > 0) {
// bytes are contained in the buffer
if (offset >= minOffset && (b.length + offset) <= maxOffset) {
System.arraycopy(buffer, subBufferIndex + offset, b, 0, b.length);
return b.length;
}
}
// grab from wrapped buffer, too many bytes, or no buffer
try {
return memBuffer.getBytes(b, computeOffset(offset));
}
catch (MemoryAccessException e) {
return 0;
}
}
@Override