Program Diff - Ghidra

Overview

Program Diff extends the CodeBrowser to display two programs side-by-side, computing and visualizing differences between them. Unlike Version Tracking which focuses on transferring analysis, Program Diff emphasizes interactive comparison and selective markup application.

Program Diff allows you to compare any two compatible programs and selectively apply differences from one program to another.

Core Capabilities

Side-by-Side View

Synchronized dual-panel display of programs

Difference Highlighting

Visual marking of all differences between programs

Selective Application

Apply specific differences to the target program

Detail View

Examine detailed differences at cursor location

Getting Started

Opening a Second Program

Open First Program

Open your primary program in the CodeBrowser.

Select Second Program

Click Tools → Program Diff → Open/Close Second Program.

Choose Program

Select from:

Currently open programs in the tool
Programs from project repository
Versioned programs from Ghidra Server

View Opens

Second program displays in right panel with synchronized scrolling.

The two programs must have similar architectures and compatible memory layouts. Programs with completely different architectures cannot be compared.

Program Compatibility

Programs are compatible when:

Same processor architecture (language)
Similar memory organization
Overlapping address spaces

// Source: ProgramDiffPlugin.java:1591-1599
// Programs are checked for similarity using:
// ProgramMemoryComparator.similarPrograms(prog1, prog2)
// which compares language IDs and basic structure

Computing Differences

Execute Diff Dialog

Open Execute Diff

Click Tools → Program Diff → Execute Diff or press the diff icon.

Configure Filters

Select which difference types to compute:

Bytes
Instructions
Comments
Labels
Functions
References
And more…

Set Scope

Choose comparison scope:

Entire program
Current selection
Specific address ranges

Execute

Click OK to compute differences.

Difference Types

Program Diff can detect differences in:

Code
Symbols
Annotations
Structure

Bytes: Raw byte differences
Instructions: Disassembly differences
Mnemonics: Instruction mnemonics only
Operands: Instruction operands

Diff Filters

Customize which differences to display:

// Source: ProgramDiffPlugin.java:628
// ProgramDiffFilter controls which difference types
// are computed and highlighted

// Common filter configurations:
// - ALL_DIFFS: Show everything
// - CODE_DIFFS: Only code differences  
// - USER_DEFINED: Only user markup

filterType

enum

Options: All Diffs, Code Diffs Only, User-Defined Only, Custom

Viewing Differences

Difference Highlighting

Differences are highlighted in both program views:

Background color: Marks addresses with differences
Margin markers: Overview of diff locations
Navigation: Jump between difference locations

The highlight color can be customized via Edit → Tool Options → Browser Fields → Difference Color.

Next Difference

Navigate to the next highlighted difference

Previous Difference

Navigate to the previous highlighted difference

Go to Address

Jump to specific address in both programs

Select All Diffs

Select all difference addresses in view

Synchronized Views

Both program panels remain synchronized:

Cursor location: Both views track the same address
Scrolling: Synchronized scroll positions
Selection: Selections span both programs
Field focus: Same field types visible

// Source: ProgramDiffPlugin.java:175-236
// programLocationChanged() handler keeps cursors
// synchronized between primary and secondary programs

Difference Details

Details Window

View detailed information about differences at current location:

Show Details

Window → Diff Details to open the details panel.

Navigate to Location

Position cursor on address with differences.

Review Details

Panel shows:

Specific differences at location
Original vs. new values
Difference categories

Details include:

Byte values: Hexadecimal comparison
Disassembly: Instruction differences
Markup: Comment and label differences
Type information: Data type differences

Difference details update automatically as you navigate through the program.

Applying Differences

Apply Settings

Configure which differences to apply:

Open Settings

Window → Diff Apply Settings to open configuration panel.

Select Categories

Choose which difference types to apply:

Replace: Overwrite with second program’s value
Merge: Combine both values (where applicable)
Ignore: Don’t apply this type

Configure Options

Set options like:

Primary symbol handling
Reference behavior
Comment merging

Applying Changes

Apply Current
Apply Selection
Apply and Next

Apply differences at current cursor location:

Position cursor on difference
Click Apply in Diff Apply Settings
Changes applied to primary program

Applying differences modifies the primary program. Use undo or save carefully.

Apply Filters

Control which categories are applied:

Category	Replace	Merge	Ignore
Bytes	Overwrite bytes	N/A	Skip
Instructions	Replace instruction	N/A	Skip
Comments	Replace comment	Append both	Skip
Labels	Replace label	Add alternate	Skip
Functions	Replace signature	Combine params	Skip
References	Replace refs	Add refs	Skip

// Source: DiffApplySettingsProvider.java
// ProgramMergeFilter configured via Apply Settings dialog
// controls which markup types are applied and how

Selection Management

Making Selections

Selections work across both programs:

Click and drag: Select range in either panel
Shift+Click: Extend selection
Ctrl+Click: Add to selection
Select All Diffs: Select all highlighted differences

Selection Actions

Set P1 Selection on P2

Transfer primary program’s selection to secondary program view.Use: Focus on same code in both programs

Ignore Selection

Mark selected differences to be ignored (not highlighted).Use: Hide unimportant differences

Apply Selection

Apply all differences within selection to primary program.Use: Bulk apply related changes

Ignore Functionality

Temporarily hide specific differences:

Select Differences

Select address range containing differences to ignore.

Ignore

Click Ignore Selection and Goto Next Difference.

Result

Selected addresses no longer highlighted as differences.

Ignored differences are not permanently removed—re-run Execute Diff to restore them.

Advanced Features

Program Context

Diff can operate in different program contexts:

Same context: Compare identical address ranges
Different context: Handle memory layout differences
Overlay support: Compare overlay address spaces

// Source: ProgramDiffPlugin.java:196-206  
// Overlay space handling converts addresses between
// programs when address spaces don't match exactly

Address Mapping

Program Diff handles address translation:

Compatible addresses: Direct mapping between programs
Overlay conversion: Map overlay spaces appropriately
Only in P1: Addresses existing only in first program
Only in P2: Addresses existing only in second program

Addresses that exist in only one program are specially marked and handled during diff operations.

Diff History

Program Diff maintains history:

Previous location: Track last cursor position
Navigation stack: Return to previous locations
Undo/Redo: Revert applied changes

Tool Configuration

Options

Configure Diff behavior via Edit → Tool Options:

Difference Color

color

Background color for highlighting differences

Cursor Sync

boolean

default:true

Keep cursors synchronized between programs

Auto Apply

boolean

default:false

Automatically apply when navigating to next diff

Window Layout

Customize panel arrangement:

Resize second program panel
Dock/undock details window
Show/hide apply settings
Configure field visibility

Comparison with Version Tracking

Feature	Program Diff	Version Tracking
Purpose	Interactive comparison	Analysis transfer
Workflow	Immediate visual diff	Multi-step correlation
Scope	Address-by-address	Function/data matching
Application	Selective manual apply	Bulk automated apply
Best For	Quick comparisons	Version migration

Use Program Diff when:

Comparing similar programs quickly
Applying specific targeted changes
Reviewing byte-level differences

Use Version Tracking when:

Migrating to new software version
Transferring comprehensive analysis
Handling major code refactoring

Use Cases

Patch Analysis

Compare original and patched executables to find fixes

Malware Variants

Identify differences between malware samples

Build Comparison

Compare debug vs. release builds

Binary Auditing

Verify compiled binary matches expected source

Obfuscation Analysis

Compare obfuscated and clean versions

Optimization Review

Analyze compiler optimization effects

Limitations and Considerations

Important Limitations:

Only one diff session per program at a time
Second program must be compatible architecture
Large programs may have slow diff computation
Memory-intensive for large address ranges
No automatic conflict resolution

Performance Tips

For Better Performance:

Limit diff scope to specific selections
Use targeted diff filters
Close unused tool windows
Apply differences incrementally
Consider Version Tracking for large-scale changes

Troubleshooting

Can't Open Second Program

Checks:

Verify programs have similar languages
Check if another diff is already open
Ensure program is in accessible project
Confirm memory compatibility

No Differences Shown

Causes:

Diff filter too restrictive
Programs are identical in selected categories
Comparison scope excludes differences

Solution: Adjust filters and scope, re-execute diff

Apply Doesn't Work

Checks:

Verify apply settings configured (not all “Ignore”)
Ensure selection includes differences
Check for transaction conflicts
Confirm program is not read-only

Slow Diff Performance

Solutions:

Reduce diff scope to selection
Disable some diff filters
Use faster system or more memory
Consider splitting into multiple sessions

Keyboard Shortcuts

Action	Shortcut	Description
Next Diff	Ctrl+N	Navigate to next difference
Previous Diff	Ctrl+P	Navigate to previous difference
Apply and Next	Ctrl+Shift+N	Apply current and go to next
Select All Diffs	Ctrl+A	Select all differences in view
Show Details	Ctrl+D	Toggle Diff Details window

Shortcuts can be customized via Edit → Tool Options → Key Bindings.

Source Code References

# Main plugin implementation
~/workspace/source/Ghidra/Features/ProgramDiff/src/main/java/ghidra/app/plugin/core/diff/

# Key files:
- ProgramDiffPlugin.java         # Main diff plugin
- DiffController.java            # Difference navigation
- ApplyDiffCommand.java          # Apply logic
- DiffApplySettingsProvider.java # Settings UI
- DiffDetailsProvider.java       # Details panel

Open/Close Second Program: Select program to compare
Execute Diff: Compute differences with filters
Next Difference: Navigate forward
Previous Difference: Navigate backward
Apply Differences: Apply at cursor or selection
Ignore Selection and Goto Next: Skip differences
Select All Differences: Select all diffs in view

Diff Details: Show/hide detailed differences
Diff Apply Settings: Configure apply behavior

Next Steps

Version Tracking

Advanced version comparison and analysis transfer

Graph Visualization

Visualize program structure and relationships

Get Started

Core Concepts

User Guide

Advanced Features

Scripting & Automation

Extension Development

Processors & Formats

​Overview

​Core Capabilities

Side-by-Side View

Difference Highlighting

Selective Application

Detail View

​Getting Started

​Opening a Second Program

​Program Compatibility

​Computing Differences

​Execute Diff Dialog

​Difference Types

​Diff Filters

​Viewing Differences

​Difference Highlighting

​Navigation Actions

Next Difference

Previous Difference

Go to Address

Select All Diffs

​Synchronized Views

​Difference Details

​Details Window

​Applying Differences

​Apply Settings

​Applying Changes

​Apply Filters

​Selection Management

​Making Selections

​Selection Actions

​Ignore Functionality

​Advanced Features

​Program Context

​Address Mapping

​Diff History

​Tool Configuration

​Options

​Window Layout

​Comparison with Version Tracking

​Use Cases

Patch Analysis

Malware Variants

Build Comparison

Binary Auditing

Obfuscation Analysis

Optimization Review

​Limitations and Considerations

​Performance Tips

​Troubleshooting

​Keyboard Shortcuts

​Source Code References

​Menu Reference

​Tools → Program Diff Menu

​Window Menu

​Next Steps

Version Tracking

Graph Visualization

Build docs developers (and LLMs) love

Overview

Core Capabilities

Getting Started

Opening a Second Program

Program Compatibility

Computing Differences

Execute Diff Dialog

Difference Types

Diff Filters

Viewing Differences

Difference Highlighting

Navigation Actions

Synchronized Views

Difference Details

Details Window

Applying Differences

Apply Settings

Applying Changes

Apply Filters

Selection Management

Making Selections

Selection Actions

Ignore Functionality

Advanced Features

Program Context

Address Mapping

Diff History

Tool Configuration

Options

Window Layout

Comparison with Version Tracking

Use Cases

Limitations and Considerations

Performance Tips

Troubleshooting

Keyboard Shortcuts

Source Code References

Menu Reference

Tools → Program Diff Menu

Window Menu

Next Steps