30178263727

Committed 25 Jul 2026 10:48PM UTC coverage: 36.302% (-0.8%) from 37.144%

Build # 30178263727

Build Type

push

github

Committed by

SamboyCoding

Commit Message

Decompiler: Recover static fields, throw helpers, and rgctx, fix bool flags, fix this param in IL, fix float handling somewhat

Coverage Stats

2890 of 9069 branches covered (31.87%)

Branch coverage included in aggregate %.

28 of 319 new or added lines in 17 files covered. (8.78%)

10 existing lines in 6 files now uncovered.

5291 of 13467 relevant lines covered (39.29%)

164158.62 hits per line

Source File
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0.0

/Cpp2IL.Core/Analysis/ThrowHelperRecovery.cs

using System;
using System.Collections.Generic;
using Cpp2IL.Core.Model.Contexts;
using Cpp2IL.Core.Utils;
using Iced.Intel;

namespace Cpp2IL.Core.Analysis;

/// <summary>
/// Finds exception throw helper functions. These eventually look up the type they throw by name
/// (via <c>Class::FromName(corlib, "System", "NullReferenceException")</c>), so the type name appears
/// as a plain C string in the helper's body.
/// </summary>
public static class ThrowHelperRecovery
{
    private const int MaxDepth = 5;
    private const int MaxStringLength = 64;

    public static TypeAnalysisContext? GetThrownException(ApplicationAnalysisContext appContext, ulong address)
    {
        var name = ResolveName(appContext, address, 0);

        if (name == null)
            return null;

        var type = appContext.LibCpp2IlContext.ReflectionCache.GetType(name);

        return type == null ? null : appContext.ResolveContextForType(type);
    }

    private static string? ResolveName(ApplicationAnalysisContext appContext, ulong address, int depth)
    {
        if (appContext.ThrowHelperNamesByAddress.TryGetValue(address, out var cached))
            return cached;

        if (address == 0 || depth >= MaxDepth)
            return null;

        // Insert before recursing so a cycle terminates
        appContext.ThrowHelperNamesByAddress[address] = null;

        InstructionList body;

        try
        {
            body = X86Utils.GetMethodBodyAtVirtAddressNew(address, true, appContext.Binary);
        }
        catch
        {
            return null;
        }

        var name = FindExceptionName(appContext, body);

        if (name == null)
        {
            foreach (var instruction in body)
            {
                if (instruction.Mnemonic != Mnemonic.Call || instruction.Op0Kind != OpKind.NearBranch64)
                    continue;

                name = ResolveName(appContext, instruction.NearBranchTarget, depth + 1);

                if (name != null)
                    break;
            }
        }

        appContext.ThrowHelperNamesByAddress[address] = name;
        return name;
    }

    private static string? FindExceptionName(ApplicationAnalysisContext appContext, InstructionList body)
    {
        foreach (var instruction in body)
        {
            if (instruction.Mnemonic != Mnemonic.Lea || !instruction.IsIPRelativeMemoryOperand)
                continue;

            if (ReadCStringAtVirtualAddress(appContext, instruction.IPRelativeMemoryAddress) is { } text && text.EndsWith("Exception", StringComparison.Ordinal))
                return text;
        }

        return null;
    }

    //TODO didn't we have a helper for this somewhere? Can't find it. Maybe got deleted. Maybe it's just too late
    private static string? ReadCStringAtVirtualAddress(ApplicationAnalysisContext appContext, ulong address)
    {
        long offset;

        try
        {
            offset = appContext.Binary.MapVirtualAddressToRaw(address, false);
        }
        catch
        {
            return null;
        }

        if (offset <= 0)
            return null;

        var content = appContext.Binary.GetRawBinaryContent();
        var end = offset;

        while (end < content.Length && end - offset < MaxStringLength && content[(int)end] != 0)
        {
            var c = content[(int)end];

            if (c < 32 || c >= 127)
                return null;

            end++;
        }

        if (end == offset || end >= content.Length || content[(int)end] != 0)
            return null;

        var characters = new char[end - offset];

        for (var i = 0; i < characters.Length; i++)
            characters[i] = (char)content[(int)offset + i];

        return new string(characters);
    }
}

1	using System;
2	using System.Collections.Generic;
3	using Cpp2IL.Core.Model.Contexts;
4	using Cpp2IL.Core.Utils;
5	using Iced.Intel;
6
7	namespace Cpp2IL.Core.Analysis;
8
9	/// <summary>
10	/// Finds exception throw helper functions. These eventually look up the type they throw by name
11	/// (via <c>Class::FromName(corlib, "System", "NullReferenceException")</c>), so the type name appears
12	/// as a plain C string in the helper's body.
13	/// </summary>
14	public static class ThrowHelperRecovery
15	{
16	private const int MaxDepth = 5;
17	private const int MaxStringLength = 64;
18
19	public static TypeAnalysisContext? GetThrownException(ApplicationAnalysisContext appContext, ulong address)
20	{
NEW 21	var name = ResolveName(appContext, address, 0);	×
22
NEW 23	if (name == null)	×
NEW 24	return null;	×
25
NEW 26	var type = appContext.LibCpp2IlContext.ReflectionCache.GetType(name);	×
27
NEW 28	return type == null ? null : appContext.ResolveContextForType(type);	×
29	}
30
31	private static string? ResolveName(ApplicationAnalysisContext appContext, ulong address, int depth)
32	{
NEW 33	if (appContext.ThrowHelperNamesByAddress.TryGetValue(address, out var cached))	×
NEW 34	return cached;	×
35
NEW 36	if (address == 0 \|\| depth >= MaxDepth)	×
NEW 37	return null;	×
38
39	// Insert before recursing so a cycle terminates
NEW 40	appContext.ThrowHelperNamesByAddress[address] = null;	×
41
42	InstructionList body;
43
44	try
45	{
NEW 46	body = X86Utils.GetMethodBodyAtVirtAddressNew(address, true, appContext.Binary);	×
NEW 47	}	×
NEW 48	catch	×
49	{
NEW 50	return null;	×
51	}
52
NEW 53	var name = FindExceptionName(appContext, body);	×
54
NEW 55	if (name == null)	×
56	{
NEW 57	foreach (var instruction in body)	×
58	{
NEW 59	if (instruction.Mnemonic != Mnemonic.Call \|\| instruction.Op0Kind != OpKind.NearBranch64)	×
60	continue;
61
NEW 62	name = ResolveName(appContext, instruction.NearBranchTarget, depth + 1);	×
63
NEW 64	if (name != null)	×
NEW 65	break;	×
66	}
67	}
68
NEW 69	appContext.ThrowHelperNamesByAddress[address] = name;	×
NEW 70	return name;	×
NEW 71	}	×
72
73	private static string? FindExceptionName(ApplicationAnalysisContext appContext, InstructionList body)
74	{
NEW 75	foreach (var instruction in body)	×
76	{
NEW 77	if (instruction.Mnemonic != Mnemonic.Lea \|\| !instruction.IsIPRelativeMemoryOperand)	×
78	continue;
79
NEW 80	if (ReadCStringAtVirtualAddress(appContext, instruction.IPRelativeMemoryAddress) is { } text && text.EndsWith("Exception", StringComparison.Ordinal))	×
NEW 81	return text;	×
82	}
83
NEW 84	return null;	×
NEW 85	}	×
86
87	//TODO didn't we have a helper for this somewhere? Can't find it. Maybe got deleted. Maybe it's just too late
88	private static string? ReadCStringAtVirtualAddress(ApplicationAnalysisContext appContext, ulong address)
89	{
90	long offset;
91
92	try
93	{
NEW 94	offset = appContext.Binary.MapVirtualAddressToRaw(address, false);	×
NEW 95	}	×
NEW 96	catch	×
97	{
NEW 98	return null;	×
99	}
100
NEW 101	if (offset <= 0)	×
NEW 102	return null;	×
103
NEW 104	var content = appContext.Binary.GetRawBinaryContent();	×
NEW 105	var end = offset;	×
106
NEW 107	while (end < content.Length && end - offset < MaxStringLength && content[(int)end] != 0)	×
108	{
NEW 109	var c = content[(int)end];	×
110
NEW 111	if (c < 32 \|\| c >= 127)	×
NEW 112	return null;	×
113
NEW 114	end++;	×
115	}
116
NEW 117	if (end == offset \|\| end >= content.Length \|\| content[(int)end] != 0)	×
NEW 118	return null;	×
119
NEW 120	var characters = new char[end - offset];	×
121
NEW 122	for (var i = 0; i < characters.Length; i++)	×
NEW 123	characters[i] = (char)content[(int)offset + i];	×
124
NEW 125	return new string(characters);	×
NEW 126	}	×
127	}

SamboyCoding / Cpp2IL / 30178263727

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