ilspy-decompile

name	ilspy-decompile
description	Decompile .NET assemblies using ilspycmd CLI tool. Invoke when you need to inspect compiled DLLs, compare original vs patched assemblies, or examine compiler-generated types (closures, iterators, state machines).

ILSpy Command-Line Decompilation

Decompile .NET assemblies using ilspycmd to inspect compiled code structure, compare builds, and debug HybridPatch issues.

Prerequisites

ilspycmd is installed as a global .NET tool:

dotnet tool install --global ilspycmd

Common Commands

List all types in an assembly

ilspycmd -l MyLibrary.dll

Use this first to discover type names, especially compiler-generated ones.

Decompile a specific type

ilspycmd -t "Namespace.ClassName" MyLibrary.dll

For nested types, use / as separator: ilspycmd -t "Outer/Inner" MyLibrary.dll

Decompile entire assembly to stdout

ilspycmd MyLibrary.dll

Decompile to a project folder

ilspycmd MyLibrary.dll -p -o ./OutputDir

Decompile to a single file

ilspycmd MyLibrary.dll > Output.cs

Key Options

Option	Description
-o, --output <dir>	Set output directory or file path
-p, --project	Export as C# Visual Studio project
-t, --type <name>	Decompile only the specified type
-l	List types without full decompilation
--no-dead-code	Remove redundant compiler-generated blocks

Typical Workflow for HybridPatch Debugging

1. List types in both original and patched DLLs to spot naming differences:

   ilspycmd -l HotfixAOT/bin/Release/net8.0/HotfixAOT.dll
   ilspycmd -l HotfixAOT/bin/Release_Patched/net8.0/HotfixAOT.dll
   

2. Compare compiler-generated types (closures <>c__DisplayClass*, state machines <Method>d__*):

   ilspycmd -t "HotfixAOT.SomeClass/<>c__DisplayClass0_0" original.dll
   ilspycmd -t "HotfixAOT.SomeClass/<>c__DisplayClass0_0" patched.dll
   

3. Inspect injected DLL to verify injection results:

   ilspycmd -t "HotfixAOT.SomeClass" HotfixAOT/Patched/HotfixAOT.dll
   

4. Check hash file for type name mappings after FixClosureNameConsistency:

   • The .hash file records type hashes used for closure renaming
   • Compare type names in hash vs actual DLL to find mismatches

Key Paths in This Project

• Original (Release) DLL: HotfixAOT/bin/Release/net8.0/HotfixAOT.dll
• Patched (Release_Patched) DLL: HotfixAOT/bin/Release_Patched/net8.0/HotfixAOT.dll
• Injected + Patched DLL: HotfixAOT/Patched/HotfixAOT.dll
• Hash file: HotfixAOT/Patched/HotfixAOT.hash
• Patch file: HotfixAOT/Patched/HotfixAOT.patch