Some high-level programs are compiled using p-code, such as C# and Visual Basic (p-code version). On the contrary, a decompiler attempts to recreate the high-level source code based on the p-code. A high-level syntax usually has an equivalent block of p-code that can by identified by the decompiler.

Programs compiled using the C language are laid to a file in plain assembly language. But since it is still a high-level language, some blocks of code can be identified back to their C syntax. The paid version of IDA Pro has an expensive, but very useful plugin, called Hex-Rays, that can identify these blocks of code and recreate the C source code.