Huge speed improvement for 32-bit games.

SamboyCoding · Jan 22, 2021 · f0c6cae · f0c6cae
1 parent 52d8e71
commit f0c6cae
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Showing 4 changed files with 41 additions and 9 deletions.
diff --git a/Cpp2IL/Extensions.cs b/Cpp2IL/Extensions.cs
@@ -9,7 +9,6 @@ namespace Cpp2IL
 {
     public static class Extensions
     {
-        public static bool IsImmediate(this OpKind opKind) => opKind >= OpKind.Immediate8 && opKind <= OpKind.Immediate32to64;
         public static T[] SubArray<T>(this T[] data, int index, int length)
         {
             var result = new T[length];

diff --git a/LibCpp2IL/Extensions.cs b/LibCpp2IL/Extensions.cs
@@ -7,6 +7,7 @@ namespace LibCpp2IL
 {
     public static class Extensions
     {
+        public static bool IsImmediate(this OpKind opKind) => opKind >= OpKind.Immediate8 && opKind <= OpKind.Immediate32to64;
         public static ulong GetRipBasedInstructionMemoryAddress(this Instruction instruction) => instruction.NextIP + instruction.MemoryDisplacement64;
 
         public static T[] SubArray<T>(this T[] data, int index, int length)

diff --git a/LibCpp2IL/PE/PE.cs b/LibCpp2IL/PE/PE.cs
@@ -329,7 +329,7 @@ public bool PlusSearch(int methodCount, int typeDefinitionsCount)
                 }
             }
 
-            ulong codeRegistration;
+            ulong codeRegistration = 0;
             ulong metadataRegistration;
 
             Console.WriteLine("Attempting to locate code and metadata registration functions...");
@@ -353,11 +353,24 @@ public bool PlusSearch(int methodCount, int typeDefinitionsCount)
                 plusSearch.SetExecSections(imageBase, dataSections);
                 metadataRegistration = plusSearch.FindMetadataRegistration64Bit();
             }
-
-            if (LibCpp2IlMain.MetadataVersion >= 24.2f)
-                codeRegistration = plusSearch.FindCodeRegistrationUsingMscorlib();
-            else
-                codeRegistration = is32Bit ? plusSearch.FindCodeRegistration() : plusSearch.FindCodeRegistration64Bit();
+
+            if (is32Bit && metadataRegistration != 0)
+            {
+                codeRegistration = plusSearch.TryFindCodeRegUsingMetaReg(metadataRegistration);
+            }
+
+            if (codeRegistration == 0)
+            {
+                if (LibCpp2IlMain.MetadataVersion >= 24.2f)
+                {
+                    Console.WriteLine("\tUsing mscorlib full-disassembly approach to get codereg, this may take a while...");
+                    codeRegistration = plusSearch.FindCodeRegistrationUsingMscorlib();
+                }
+                else
+                    codeRegistration = is32Bit ? plusSearch.FindCodeRegistration() : plusSearch.FindCodeRegistration64Bit();
+            }
+
+
 
 #if ALLOW_CODEREG_FALLBACK
             if (codeRegistration == 0 || metadataRegistration == 0)

diff --git a/LibCpp2IL/PlusSearch.cs b/LibCpp2IL/PlusSearch.cs
@@ -151,6 +151,25 @@ private IEnumerable<ulong> FindAllMappedWords(ulong va)
         // Find all valid virtual address pointers to a set of virtual addresses
         private IEnumerable<ulong> FindAllMappedWords(IEnumerable<ulong> va) => va.SelectMany(FindAllMappedWords);
 
+        public ulong TryFindCodeRegUsingMetaReg(ulong metadataRegistration)
+        {
+            var textSection = _pe.sections.First(s => s.Name == ".text");
+            var toDisasm = _pe.raw.SubArray((int) textSection.PointerToRawData, (int) textSection.SizeOfRawData);
+            var allInstructions = LibCpp2ILUtils.DisassembleBytesNew(_pe.is32Bit, toDisasm, textSection.VirtualAddress + _pe.imageBase);
+
+            var pushMetaReg = allInstructions.FirstOrDefault(i => i.Mnemonic == Mnemonic.Push && i.Op0Kind.IsImmediate() && i.GetImmediate(0) == metadataRegistration);
+            if (pushMetaReg.Mnemonic == Mnemonic.Push) //Check non-default.
+            {
+                var idx = allInstructions.IndexOf(pushMetaReg);
+                //Code reg has to be pushed after meta reg, cause that's how functions are called on 32-bit stdcall.
+                var hopefullyPushCodeReg = allInstructions[idx + 1];
+                if (hopefullyPushCodeReg.Mnemonic == Mnemonic.Push && hopefullyPushCodeReg.Op0Kind.IsImmediate())
+                    return hopefullyPushCodeReg.GetImmediate(0);
+            }
+
+            return 0;
+        }
+
         internal ulong FindCodeRegistrationUsingMscorlib()
         {
             //Works only on >=24.2
@@ -197,7 +216,7 @@ internal ulong FindCodeRegistrationUsingMscorlib()
                     if (sanity++ > 500) break;
 
                     endOfCodeGenRegAddr = endOfCodeGenRegAddr.Select(va => va - 4);
-                    codeRegVas = FindAllMappedWords(endOfCodeGenRegAddr);
+                    codeRegVas = FindAllMappedWords(endOfCodeGenRegAddr).AsParallel().ToList();
                 }
 
                 if (endOfCodeGenRegAddr.Count() != 1)
@@ -206,7 +225,7 @@ internal ulong FindCodeRegistrationUsingMscorlib()
                 return endOfCodeGenRegAddr.First();
             }
         }
-
+        
         private ulong FindCodeRegistration64BitPost2019()
         {
             //NOTE: With 64-bit ELF binaries we should iterate on exec, on everything else data.