Prevent users from adding cycles between variables using labels

Bit Slicer.xcodeproj/project.pbxproj

@@ -18,6 +18,7 @@
 		72130FC82BE6836A00691AED /* ZGEditLabelWindowController.m in Sources */ = {isa = PBXBuildFile; fileRef = 72130FC62BE6836A00691AED /* ZGEditLabelWindowController.m */; };
 		72130FCC2BE83BF400691AED /* Edit Label Dialog.xib in Resources */ = {isa = PBXBuildFile; fileRef = 72130FCB2BE83BF400691AED /* Edit Label Dialog.xib */; };
 		72130FD52BE84B4B00691AED /* [Code] Edit Variable Label.strings in Resources */ = {isa = PBXBuildFile; fileRef = 72130FD32BE84B4B00691AED /* [Code] Edit Variable Label.strings */; };
+		72130FF82BF00FAB00691AED /* [Code] Edit Variable Address.strings in Resources */ = {isa = PBXBuildFile; fileRef = 72130FF62BF00FAB00691AED /* [Code] Edit Variable Address.strings */; };
 		721594FE24DF36360027F600 /* HexFiend.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 721594FD24DF36360027F600 /* HexFiend.framework */; };
 		7215950024DF36520027F600 /* HexFiend.framework in Copy Frameworks */ = {isa = PBXBuildFile; fileRef = 721594FD24DF36360027F600 /* HexFiend.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		721B3C4D2AED913200F85660 /* ZGSearchProtectionMode.m in Sources */ = {isa = PBXBuildFile; fileRef = 720C192B271B4F9700740C8E /* ZGSearchProtectionMode.m */; };
@@ -331,6 +332,9 @@
 		72130FD42BE84B4B00691AED /* en */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = en; path = "Bit Slicer/en.lproj/[Code] Edit Variable Label.strings"; sourceTree = "<group>"; };
 		72130FD62BE84B5B00691AED /* es */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = es; path = "Bit Slicer/es.lproj/[Code] Edit Variable Label.strings"; sourceTree = "<group>"; };
 		72130FD72BE84B6400691AED /* ru */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = ru; path = "Bit Slicer/ru.lproj/[Code] Edit Variable Label.strings"; sourceTree = "<group>"; };
+		72130FF72BF00FAB00691AED /* en */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = en; path = "Bit Slicer/en.lproj/[Code] Edit Variable Address.strings"; sourceTree = "<group>"; };
+		72130FF92BF00FB300691AED /* es */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = es; path = "Bit Slicer/es.lproj/[Code] Edit Variable Address.strings"; sourceTree = "<group>"; };
+		72130FFA2BF00FBD00691AED /* ru */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = ru; path = "Bit Slicer/ru.lproj/[Code] Edit Variable Address.strings"; sourceTree = "<group>"; };
 		721594FD24DF36360027F600 /* HexFiend.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = HexFiend.framework; path = deps/HexFiend/HexFiend.framework; sourceTree = "<group>"; };
 		721594FF24DF36460027F600 /* HFLineCountingView.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; name = HFLineCountingView.h; path = deps/HexFiend/HFLineCountingView.h; sourceTree = "<group>"; };
 		722CAA5519AD4AED009C6AAE /* hotkey.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; name = hotkey.png; path = "Bit Slicer/preficons/hotkey.png"; sourceTree = "<group>"; };
@@ -1039,6 +1043,7 @@
 				724A9F3719A813D600E72C9D /* [Code] Edit Variable Value.strings */,
 				724A9F3A19A8173900E72C9D /* [Code] Edit Variable Size.strings */,
 				72130FD32BE84B4B00691AED /* [Code] Edit Variable Label.strings */,
+				72130FF62BF00FAB00691AED /* [Code] Edit Variable Address.strings */,
 				724A9F3D19A823C300E72C9D /* [Code] Search Document.strings */,
 				724A9F4F19A8F54600E72C9D /* [Code] Search Document.stringsdict */,
 				724A9F4019A85D3F00E72C9D /* [Code] Search Table.strings */,
@@ -1600,6 +1605,7 @@
 				726CA2D719606E3800A6AD40 /* Watch Variable Dialog.xib in Resources */,
 				722CAA5919AD4AED009C6AAE /* hotkey.png in Resources */,
 				77F115AE17D2EAE4009E002A /* bitslicerdocicon.iconset in Resources */,
+				72130FF82BF00FAB00691AED /* [Code] Edit Variable Address.strings in Resources */,
 				7231440E19C6230F00FBE342 /* [Code] Watch Variable.stringsdict in Resources */,
 				724A9F2519A1657500E72C9D /* [Code] Memory Viewer Status Bar.strings in Resources */,
 				77F115AF17D2EAE4009E002A /* bitslicericon.iconset in Resources */,
@@ -1865,6 +1871,16 @@
 			name = "[Code] Edit Variable Label.strings";
 			sourceTree = "<group>";
 		};
+		72130FF62BF00FAB00691AED /* [Code] Edit Variable Address.strings */ = {
+			isa = PBXVariantGroup;
+			children = (
+				72130FF72BF00FAB00691AED /* en */,
+				72130FF92BF00FB300691AED /* es */,
+				72130FFA2BF00FBD00691AED /* ru */,
+			);
+			name = "[Code] Edit Variable Address.strings";
+			sourceTree = "<group>";
+		};
 		7231440C19C6230F00FBE342 /* [Code] Watch Variable.stringsdict */ = {
 			isa = PBXVariantGroup;
 			children = (

Bit Slicer/ZGCalculator.h

@@ -60,6 +60,7 @@ NS_ASSUME_NONNULL_BEGIN
 + (BOOL)extractIndirectBaseAddress:(ZGMemoryAddress *)outBaseAddress expression:(NSString *)initialExpression process:(ZGProcess * __unsafe_unretained)process variableController:(nullable ZGVariableController * __unsafe_unretained)variableController failedImages:(NSMutableArray<NSString *> * __unsafe_unretained)failedImages;
 
 + (nullable NSString *)extractFirstDependentLabelFromExpression:(NSString *)expression;
++ (BOOL)getVariableCycle:(NSArray<NSString *> * _Nullable __autoreleasing *_Nullable)outCycle variable:(ZGVariable *)variable variableController:(ZGVariableController *)variableController;
 
 + (BOOL)parseLinearExpression:(NSString *)linearExpression andGetAdditiveConstant:(NSString * _Nullable * _Nonnull)additiveConstantString multiplicateConstant:(NSString *_Nullable * _Nonnull)multiplicativeConstantString;
 

Bit Slicer/ZGCalculator.m

@@ -945,7 +945,8 @@ + (nullable NSString *)_extractFirstDependentLabelFromExpression:(DDExpression *
 + (nullable NSString *)extractFirstDependentLabelFromExpression:(NSString *)initialExpression
 {
 	NSError *expressionError = NULL;
-	DDExpression *expression = [DDExpression expressionFromString:initialExpression error:&expressionError];
+	NSString *substitutedExpression = [self expressionBySubstitutingCalculatePointerFunctionInExpression:initialExpression];
+	DDExpression *expression = [DDExpression expressionFromString:substitutedExpression error:&expressionError];
 	if (expression == nil)
 	{
 		return nil;
@@ -954,6 +955,110 @@ + (nullable NSString *)extractFirstDependentLabelFromExpression:(NSString *)init
 	return [self _extractFirstDependentLabelFromExpression:expression];
 }
 
++ (BOOL)_expressionIsCyclic:(DDExpression *)expression cycle:(NSArray<NSString *> * __autoreleasing *)outCycle variableController:(ZGVariableController *)variableController visitedLabels:(NSMutableOrderedSet<NSString *> *)visitedLabels
+{
+	switch (expression.expressionType)
+	{
+		case DDExpressionTypeFunction:
+		{
+			if ([expression.function isEqualToString:ZGFindLabelFunction])
+			{
+				if (expression.arguments.count != 1)
+				{
+					return NO;
+				}
+
+				DDExpression *argumentExpression1 = expression.arguments[0];
+				if (argumentExpression1.expressionType != DDExpressionTypeVariable)
+				{
+					return NO;
+				}
+
+				NSString *label = argumentExpression1.variable;
+				if ([visitedLabels containsObject:label])
+				{
+					if (outCycle != NULL)
+					{
+						*outCycle = [visitedLabels.array arrayByAddingObject:label];
+					}
+					return YES;
+				}
+
+				[visitedLabels addObject:label];
+
+				ZGVariable *newLabelVariable = [variableController variableForLabel:label];
+				if (newLabelVariable == nil)
+				{
+					return NO;
+				}
+
+				// Recurse into the new variable label
+				NSString *addressFormula = newLabelVariable.addressFormula;
+				NSString *substitutedAddressFormulaExpression = [self expressionBySubstitutingCalculatePointerFunctionInExpression:addressFormula];
+
+				NSError *expressionError = NULL;
+				DDExpression *addressFormulaExpression = [DDExpression expressionFromString:substitutedAddressFormulaExpression error:&expressionError];
+				if (addressFormulaExpression == nil)
+				{
+					return NO;
+				}
+
+				return [self _expressionIsCyclic:addressFormulaExpression cycle:outCycle variableController:variableController visitedLabels:visitedLabels];
+			}
+
+			if (expression.arguments.count != 2)
+			{
+				return NO;
+			}
+
+			DDExpression *argumentExpression1 = expression.arguments[0];
+			DDExpression *argumentExpression2 = expression.arguments[1];
+
+			BOOL hasCycleInExpression1 = NO;
+			if (argumentExpression1.expressionType == DDExpressionTypeFunction)
+			{
+				// If we have label("A") + label("B") we want to use two different copies of visitedLabels
+				hasCycleInExpression1 = [self _expressionIsCyclic:argumentExpression1 cycle:outCycle variableController:variableController visitedLabels:[visitedLabels mutableCopy]];
+				if (hasCycleInExpression1)
+				{
+					return YES;
+				}
+			}
+
+			if (argumentExpression2.expressionType == DDExpressionTypeFunction)
+			{
+				return [self _expressionIsCyclic:argumentExpression2 cycle:outCycle variableController:variableController visitedLabels:visitedLabels];
+			}
+
+			return NO;
+		}
+		case DDExpressionTypeVariable:
+		case DDExpressionTypeNumber:
+			return NO;
+	}
+}
+
++ (BOOL)getVariableCycle:(NSArray<NSString *> * __autoreleasing *)outCycle variable:(ZGVariable *)variable variableController:(ZGVariableController *)variableController
+{
+	NSString *label = variable.label;
+	if (label.length == 0 || !variable.usesDynamicLabelAddress)
+	{
+		return NO;
+	}
+
+	NSString *initialExpression = [self expressionBySubstitutingCalculatePointerFunctionInExpression:variable.addressFormula];
+
+	NSError *expressionError = NULL;
+	DDExpression *expression = [DDExpression expressionFromString:initialExpression error:&expressionError];
+	if (expression == nil)
+	{
+		return NO;
+	}
+
+	NSMutableOrderedSet<NSString *> *visitedLabels = [NSMutableOrderedSet orderedSetWithObject:label];
+	return [self _expressionIsCyclic:expression cycle:outCycle variableController:variableController visitedLabels:visitedLabels];
+}
+
 + (BOOL)isValidExpression:(NSString *)expression
 {
 	return [[expression stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] length] > 0;

Bit Slicer/ZGEditAddressWindowController.m

@@ -34,6 +34,9 @@
 #import "ZGVariableController.h"
 #import "ZGVariable.h"
 #import "ZGNullability.h"
+#import "ZGRunAlertPanel.h"
+
+#define ZGEditAddressLocalizableTable @"[Code] Edit Variable Address"
 
 @implementation ZGEditAddressWindowController
 {
@@ -73,12 +76,18 @@ - (void)requestEditingAddressFromVariable:(ZGVariable *)variable attachedToWindo
 
 - (IBAction)editAddress:(id)__unused sender
 {
+	NSString *newAddressFormula = _addressTextField.stringValue;
+	NSString *cycleInfo = nil;
+	if (![_variableController editVariables:@[ZGUnwrapNullableObject(_variable)] addressFormulas:@[newAddressFormula] cycleInfo:&cycleInfo])
+	{
+		ZGRunAlertPanelWithOKButton(NSLocalizedStringFromTable(@"addressCycleAlertTitle", ZGEditAddressLocalizableTable, nil), [NSString stringWithFormat:NSLocalizedStringFromTable(@"addressCycleAlertMessageFormat", ZGEditAddressLocalizableTable, nil), newAddressFormula, cycleInfo]);
+		return;
+	}
+
 	NSWindow *window = ZGUnwrapNullableObject([self window]);
 	[NSApp endSheet:window];
 	[window close];
 
-	[_variableController editVariables:@[ZGUnwrapNullableObject(_variable)] addressFormulas:@[_addressTextField.stringValue]];
-
 	_variable = nil;
 }
 

Bit Slicer/ZGEditLabelWindowController.m

@@ -280,12 +280,17 @@ - (IBAction)editVariablesLabels:(id)__unused sender
 		return;
 	}
 
+	NSString *cycleInfo = nil;
+	if (![_variableController editVariables:ZGUnwrapNullableObject(_variables) requestedLabels:requestedLabels cycleInfo:&cycleInfo])
+	{
+		ZGRunAlertPanelWithOKButton(NSLocalizedStringFromTable(@"labelCycleAlertTitle", ZGEditLabelLocalizableTable, nil), [NSString stringWithFormat:NSLocalizedStringFromTable(@"labelCycleAlertMessageFormat", ZGEditLabelLocalizableTable, nil), cycleInfo]);
+		return;
+	}
+
 	NSWindow *window = ZGUnwrapNullableObject(self.window);
 	[NSApp endSheet:window];
 	[window close];
 
-	[_variableController editVariables:ZGUnwrapNullableObject(_variables) requestedLabels:requestedLabels];
-
 	_variables = nil;
 }
 

Bit Slicer/ZGPyDebugger.m

@@ -1507,10 +1507,21 @@ static BOOL writeRegister(NSDictionary<NSString *, NSValue *> *registerOffsetsDi
 
 	ZGVariableController *variableController = self->objcSelf->_variableController;
 
+	ZGPyDebugger *debugger = self->objcSelf;
 	dispatch_async(dispatch_get_main_queue(), ^{
 		ZGVariable *variable = [variableController variableForLabel:labelString];
-
-		[variableController editVariables:@[variable] addressFormulas:@[addressString]];
+		if (variable == nil)
+		{
+			[debugger->_loggerWindowController writeLine:[NSString stringWithFormat:@"Error: updateVariable() failed to identify variable with label '%@'", labelString]];
+		}
+		else
+		{
+			NSString *cycleInfo = nil;
+			if (![variableController editVariables:@[variable] addressFormulas:@[addressString] cycleInfo:&cycleInfo])
+			{
+				[debugger->_loggerWindowController writeLine:[NSString stringWithFormat:@"Error: updateVariable() failed to update label '%@' with address '%@' due to cycle '%@'", labelString, addressString, cycleInfo]];
+			}
+		}
 	});
 
 	return Py_BuildValue("");

Bit Slicer/ZGVariableController.h

@@ -89,9 +89,9 @@ typedef struct
 + (void)annotateVariables:(NSArray<ZGVariable *> *)variables process:(ZGProcess *)process variableController:(nullable ZGVariableController *)variableController symbols:(BOOL)requiresSymbols async:(BOOL)async completionHandler:(void (^)(void))completionHandler;
 
 - (void)editVariables:(NSArray<ZGVariable *> *)variables newValues:(NSArray<NSString *> *)newValues;
-- (void)editVariables:(NSArray<ZGVariable *> *)variables addressFormulas:(NSArray<NSString *> *)newAddressFormulas;
+- (BOOL)editVariables:(NSArray<ZGVariable *> *)variables addressFormulas:(NSArray<NSString *> *)newAddressFormulas cycleInfo:(NSString * _Nullable __autoreleasing *_Nullable)outCycleInfo;
 - (void)editVariables:(NSArray<ZGVariable *> *)variables requestedSizes:(NSArray<NSNumber *> *)requestedSizes;
-- (void)editVariables:(NSArray<ZGVariable *> *)variables requestedLabels:(NSArray<NSString *> *)requestedLabels;
+- (BOOL)editVariables:(NSArray<ZGVariable *> *)variables requestedLabels:(NSArray<NSString *> *)requestedLabels cycleInfo:(NSString * _Nullable __autoreleasing *_Nullable)outCycleInfo;
 
 - (nullable ZGVariable *)variableForLabel:(NSString *)label;