14 Aug 2025
“Why Your Decompiler’s Output Is Obfuscated—and How to Make Sense of It”
Why Your Decompiler’s Output Is Obfuscated—and How to Make Sense of It
Meta Description:
Decompiled EX4 code often looks messy and unreadable. Learn why your decompiler output is obfuscated and discover techniques to make sense of it for editing or debugging.
Introduction
You’ve just decompiled your EX4 file into MQL4, expecting a clean, readable source code… but what you get is a confusing mess of random variable names, no comments, and inconsistent formatting.
This isn’t a sign your decompiler is broken — it’s a normal result of how compiled code works. In this post, we’ll explain why decompiled output is obfuscated, what that means for you, and how to untangle it so you can actually understand and work with the code.
Why Decompiled Output is Obfuscated
When MetaTrader 4 compiles an MQ4 source file into an EX4 executable, it strips away all the human-friendly information that makes source code easy to read.
1. Variable and Function Name Loss
• Your original MovingAverageLength variable might be renamed to var_1 or m1.
• Functions like CalculateLotSize() may become f3() or sub_2().
• This is because compiled code stores memory addresses, not original text labels.
2. No Comments or Documentation
• Any comments like // This function calculates the stop loss are completely removed.
• This is intentional — comments exist only in source code for human understanding.
3. Flattened Formatting
• Indentation, spacing, and line breaks are often ignored by the compiler.
• Decompiled output is typically one giant block of code with no visual structure.
4. Compiler Optimizations
• The MT4 compiler may rearrange, merge, or simplify instructions to run faster.
• This can make the decompiled code logically correct but structurally different from the original.
5. Anti-Decompilation Obfuscation
• Some developers intentionally use obfuscation tools before compiling.
• This can create misleading function flows, unused code blocks, and variable renaming to make reverse engineering harder.
How to Make Sense of Obfuscated Decompiled Code
Even if the output looks messy, you can take steps to restore readability.
1. Rename Variables and Functions
• Start by identifying what each variable does through its use in the code.
• Give them descriptive names like OrderLots, StopLossPoints, or TrendDirection.
2. Re-Indent and Re-Format
• Use a code beautifier or formatting tool for MQL4.
• This will restore indentation and help you see loops, conditions, and code blocks more clearly.
3. Comment as You Go
• Add inline comments whenever you figure out what a piece of code does.
4. Trace Logic Flow
• Follow the main start() or OnTick() function first.
• Work your way outward to helper functions.
5. Compare with Known MQL4 Templates
• Look for familiar indicator or EA structures.
• Many EAs follow similar logic for placing trades, setting stops, and managing risk.
Can You Fully Restore the Original?
The short answer is: No.
• The functional logic can often be recovered 80–90%.
• Original naming, comments, and exact code style are gone forever.
• Your goal isn’t to get the exact original back, but to get a usable, understandable version.
Legal Reminder
Before you attempt to clean up decompiled code, make sure you:
• Own the rights to the original EA or indicator.
• Have permission from the author.
Decompiling without permission is a violation of MetaTrader’s EULA and copyright law.
