30166321939

Committed 25 Jul 2026 04:47PM UTC coverage: 37.297% (-0.2%) from 37.493%

Build # 30166321939

Build Type

push

github

Committed by

SamboyCoding

Commit Message

Decompiler: Find and remove write barriers

Coverage Stats

2875 of 8674 branches covered (33.15%)

Branch coverage included in aggregate %.

0 of 54 new or added lines in 4 files covered. (0.0%)

2 existing lines in 1 file now uncovered.

5271 of 13167 relevant lines covered (40.03%)

167893.48 hits per line

Source File
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0.0

/Cpp2IL.Core/Analysis/KeyFunctionRecovery.cs

using System.Collections.Generic;
using System.Linq;
using Cpp2IL.Core.Il2CppApiFunctions;
using Cpp2IL.Core.ISIL;
using Cpp2IL.Core.Model.Contexts;

namespace Cpp2IL.Core.Analysis;

/// <summary>
/// Maps calls to KeyFunctionAddresses to their underlying IL opcodes. E.g. il2cpp_codegen_object_new => newobj.
/// Eventually will include box/unbox/throw/etc
/// </summary>
public static class KeyFunctionRecovery
{
    //All of these have the same params in the same order so we treat them as equal.
    private static readonly HashSet<string> ObjectNewFunctions =
    [
        "il2cpp_object_new",
        "il2cpp_vm_object_new",
        "il2cpp_codegen_object_new",
    ];

    public static void Run(MethodAnalysisContext method)
    {
        foreach (var instruction in method.ControlFlowGraph!.Blocks.SelectMany(block => block.Instructions))
        {
            if (instruction.Operands is not [string keyFunction, ..])
                continue;

            if (ObjectNewFunctions.Contains(keyFunction))
                RewriteObjectNew(instruction);
            else if (keyFunction == nameof(BaseKeyFunctionAddresses.il2cpp_codegen_write_barrier))
                RemoveWriteBarrier(instruction);
        }
    }

    private static void RemoveWriteBarrier(Instruction instruction)
    {
        instruction.OpCode = OpCode.Nop;
        instruction.Operands = [];
    }
    
    private static void RewriteObjectNew(Instruction instruction)
    {
        // Needs the function name, the result, and the class argument.
        if (instruction.OpCode != OpCode.Call || instruction.Operands.Count < 3)
            return;

        var result = instruction.Operands[1];
        var klass = instruction.Operands[2];

        instruction.OpCode = OpCode.Newobj;
        instruction.Operands = [result, klass];
    }
}

1	using System.Collections.Generic;
2	using System.Linq;
3	using Cpp2IL.Core.Il2CppApiFunctions;
4	using Cpp2IL.Core.ISIL;
5	using Cpp2IL.Core.Model.Contexts;
6
7	namespace Cpp2IL.Core.Analysis;
8
9	/// <summary>
10	/// Maps calls to KeyFunctionAddresses to their underlying IL opcodes. E.g. il2cpp_codegen_object_new => newobj.
11	/// Eventually will include box/unbox/throw/etc
12	/// </summary>
13	public static class KeyFunctionRecovery
14	{
15	//All of these have the same params in the same order so we treat them as equal.
16	private static readonly HashSet<string> ObjectNewFunctions =	×
17	[	×
18	"il2cpp_object_new",	×
19	"il2cpp_vm_object_new",	×
20	"il2cpp_codegen_object_new",	×
21	];	×
22
23	public static void Run(MethodAnalysisContext method)
24	{
25	foreach (var instruction in method.ControlFlowGraph!.Blocks.SelectMany(block => block.Instructions))	×
26	{
27	if (instruction.Operands is not [string keyFunction, ..])	×
28	continue;
29
30	if (ObjectNewFunctions.Contains(keyFunction))	×
31	RewriteObjectNew(instruction);	×
NEW 32	else if (keyFunction == nameof(BaseKeyFunctionAddresses.il2cpp_codegen_write_barrier))	×
NEW 33	RemoveWriteBarrier(instruction);	×
34	}
35	}	×
36
37	private static void RemoveWriteBarrier(Instruction instruction)
38	{
NEW 39	instruction.OpCode = OpCode.Nop;	×
NEW 40	instruction.Operands = [];	×
NEW 41	}	×
42
43	private static void RewriteObjectNew(Instruction instruction)
44	{
45	// Needs the function name, the result, and the class argument.
46	if (instruction.OpCode != OpCode.Call \|\| instruction.Operands.Count < 3)	×
47	return;	×
48
49	var result = instruction.Operands[1];	×
50	var klass = instruction.Operands[2];	×
51
52	instruction.OpCode = OpCode.Newobj;	×
53	instruction.Operands = [result, klass];	×
54	}	×
55	}

SamboyCoding / Cpp2IL / 30166321939

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