- VB Decompiler is an advanced tool that can decompile programs (EXE, DLL, or OCX) written in Visual Basic 5.0/6.0 and disassemble programs based on.NET technology. As you know, programs written in Visual Basic can be compiled to interpreted p-code or to native code, and a.NET assembly is always compiled to Microsoft intermediate language.
- Hi Guys, Is there a decompiler for vb6? I need to view the source code from assignments i did in uni a few years ago. I can see via the ee search engine, this question has been asked many times with little luck.
- Spices.Net Decompiler is a efficient and flexible tool, that converts.NET binaries (.EXE or.DLL) from binary format to a beautifully formatted, optimized and commented source code, generates equivalent and recompilable code that is remarkably close to the original source code, product of well known Spices.Net products family.
Decompiler reads program binaries, decompiles them, infers data types, and emits structured C source code. Designed with a pluggable architecture, it currently has: - support for x86, 68k, PowerPC processors (partial support for Arm, Mips, Sparc, Z80, m6502, PDP-11) - support for EXE, Elf, AmigaOS Hunk executable formats - support for MS-DOS, Win32, U.ix, AmigaOS (partial for C64, ZX-81.
Introduction
This is the home page of (yet another) open source machine code decompiler project. The goal of a machine code decompiler is to analyze executable files (like .EXE or .DLL files in Windows or ELF files in Unix-like environments) and attempt to create a high level representation of the machine code in the executable file:the decompiler tries to reconstruct the source code from which the executable was compiled in the first place.To download the Decompiler, go to the project page:
https://sourceforge.net/projects/decompiler
https://sourceforge.net/projects/decompiler
Since compilation is a non-reversible process (information such as comments and variable data types is irretrievably lost), decompilation can never completely recover the source code of a machine code executable. However, with some oracular (read 'human') assistance, it can go a long waytowards this goal. An oracle can provide function parameter types, the locations of otherwise unreachable code, and user-specified comments.
The decompiler is designed to be processor- and platform-agnostic. The intent is that you should be able to useit to decompile executables for any processor architecture and not be tied to a particular instruction set. Although currently only a x86 front end is implemented, there is nothing preventing you from implementing a 68K, Sparc, or VAX front end if you need one.
Convert Exe To Source Code
The decompiler can be run as a command-line tool, in which case it can be fed either with a simple executable file, or a decompiler project file, which not only specifies the executable file to decompile but also any oracular information that assists its work. The decompiler also has a graphical front end, which lets an operator specify oracular information while examining the decompiled executable.
The outputs of the decompiler are a C source code file containing all the disassembled code and a header file in which type-reconstructed data types can be found.
Design
The decompiler consists of several phases.- The loading phase loads the executable into memory and determines what kind of executable is being decompiled. The executable format usually defines the processor format and the expected operating system environment. For older formats, such as plain MS-DOS .EXE files, the processor (x86 real mode) and operating system environent (MS-DOS) are implicit. Once the format is determined, the binary is loaded into memory (uncompressing it if necessary) and pointer or segment relocations are carried out. These relocations are also helpfulin later stages of the decompiler, as each relocated pointer valuecan be given a preliminary type pointer-to(<unknown>) andeach relocated segment selector the type segment-selector.
- The scanning phase follows the loading phase. The executablewill usually have one or more entry points, addresses pointing to executable code. The code at the the entry points is disassembled and traced, looking in particular for branch, call, and return statements. Successively, individual procedures are discovered, and call graph is built up, whose edges represent calls between procedures.
- The rewriting phase rewrites all machine-specific instructions into low-level machine-independent instructions. Idiomatic instruction sequences are rewritten to expressions. From this point on, the decompilation process is processor independent.
- The analysis phase first does a interprocedural reaching definitions analysis. This is done to determine, for each procedure proc of the program, which processor registersare preserved and which processor registers are modified after a call to proc. A subsequent interprocedural liveness analysis, combined with the results of the reaching definitions analysis, determins which processor registers are used as parameters and return value registers for each procedure. Note that this analysis avoids depending on a specific processor/platform ABI or calling convention. Once the two interprocedural analyses are complete, the procedures can be rewritten with their explicit arguments. Subsequent analyses are then performed on a procedure-by-procedure basis. Procedures are converted into SSA Form, condition code flags are eliminated and expressions are simplified. Finally the procedures are converted out of SSA Form.
- The interprocedural type analysis phase attempts to recover the data types used in the program by analyzing the way in which values are used by the program code, incorporating clues obtained from the relocation data as well as any 'oracular' information provided by the user. Memory access expressions are converted into their C equivalents: pointer dereferences (*foo), member access expressions (foo->bar), and array references (foo[bar]).
- Finally, a structure analysis rewrites the control structures from unstructured goto-sphaghetti code to C-language if, while- / do-loops, and switch-statements.
How To Decompile Code
Development
Decompile A Program
The decompiler is written in C# and currently targets CLR version 2.0.It's currently developed with Visual Studio 2005, but the planis to have a working MonoDevelop project soon (wanna pitch in?)The project implements the Test Driven Development methodology, with heavy emphasis on unit testing.No new code is allowed into the project unless it has one or more associated tests written for it. Developing a decompiler is notoriously tricky work with lots of special cases. Not having unit tests would make development an eternal bug hunt as fixes for one bug introduce other bugs. Unit tests are developed using NUnit v2.2.
Subversion is used for source control.