Allow relating variables with negative offset

Also lax requirement of variable's address being 'meaningful' to be >= the process's main mach binary header address.
zorgiepoo · May 12, 2024 · af8031a · af8031a
1 parent 8480593
commit af8031a
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Showing 2 changed files with 21 additions and 6 deletions.
diff --git a/Bit Slicer/ZGDocumentTableController.m b/Bit Slicer/ZGDocumentTableController.m
@@ -369,7 +369,10 @@ - (NSDragOperation)tableView:(NSTableView *)__unused tableView validateDrop:(id
 			for (NSNumber *draggingRow in draggingRows)
 			{
 				ZGVariable *draggingVariable = documentVariables[draggingRow.unsignedIntegerValue];
-				if (draggingVariable.type == ZGScript || draggingVariable.usesDynamicLabelAddress)
+				// Even if the label already uses a label in its address,
+				// we should still allow the user to override the address if they want
+				// to change the relation of the variable from one label to another one
+				if (draggingVariable.type == ZGScript)
 				{
 					return NSDragOperationNone;
 				}

diff --git a/Bit Slicer/ZGVariableController.m b/Bit Slicer/ZGVariableController.m
@@ -1029,27 +1029,30 @@ - (void)relateVariables:(NSArray<ZGVariable *> *)variables toLabeledVariable:(ZG
 	ZGDocumentWindowController *windowController = _windowController;
 	ZGProcess *process = windowController.currentProcess;
 
-	// If there are any duplicate addresses or any address is zero or the addresses are <= than the labeled variable
+	ZGMemoryAddress mainBinaryHeaderAddress = process.mainMachBinary.headerAddress;
+
+	// If there are any duplicate addresses or any address < mainBinaryHeaderAddress
 	// we will assume the variable's addresses are not meaningful and can be overwritten based on stride
 	// Otherwise we will assume the current addresses are meaningful and are relative to the labeled variable
 	ZGMemoryAddress labeledVariableAddress = labeledVariable.address;
 	NSMutableSet<NSNumber *> *visitedAddresses = [NSMutableSet set];
 	BOOL currentAddressesRelatable = YES;
 	for (ZGVariable *variable in variables)
 	{
-		if (variable.address == 0x0 || variable.address <= labeledVariableAddress)
+		if (variable.address < mainBinaryHeaderAddress)
 		{
 			currentAddressesRelatable = NO;
 			break;
 		}
 
-		if ([visitedAddresses containsObject:@(variable.address)])
+		NSNumber *variableAddress = @(variable.address);
+		if ([visitedAddresses containsObject:variableAddress])
 		{
 			currentAddressesRelatable = NO;
 			break;
 		}
 
-		[visitedAddresses addObject:@(variable.address)];
+		[visitedAddresses addObject:variableAddress];
 	}
 
 	NSMutableArray<NSString *> *newAddressFormulas = [NSMutableArray array];
@@ -1082,7 +1085,16 @@ - (void)relateVariables:(NSArray<ZGVariable *> *)variables toLabeledVariable:(ZG
 	{
 		for (ZGVariable *variable in variables)
 		{
-			NSString *newAddressFormula = [NSString stringWithFormat:@"label(\"%@\") + 0x%llX", label, variable.address - labeledVariableAddress];
+			ZGMemoryAddress variableAddress = variable.address;
+			NSString *newAddressFormula;
+			if (variableAddress >= labeledVariableAddress)
+			{
+				newAddressFormula = [NSString stringWithFormat:@"label(\"%@\") + 0x%llX", label, variableAddress - labeledVariableAddress];
+			}
+			else
+			{
+				newAddressFormula = [NSString stringWithFormat:@"label(\"%@\") - 0x%llX", label, labeledVariableAddress - variableAddress];
+			}
 
 			[newAddressFormulas addObject:newAddressFormula];
 		}