Refactor `PtcInfo` (#2625)

* Refactor `PtcInfo`

This change reduces the coupling of `PtcInfo` by moving relocation
tracking to the backend. `RelocEntry`s remains as `RelocEntry`s through
out the pipeline until it actually needs to be written to the PTC
streams. Keeping this representation makes inspecting and manipulating
relocations after compilations less painful. This is something I needed
to do to patch relocations to 0 to diff dumps.

Contributes to #1125.

* Turn `Symbol` & `RelocInfo` into readonly structs

* Add documentation to `CompiledFunction`

* Remove `Compiler.Compile<T>`

Remove `Compiler.Compile<T>` and replace it by `Map<T>` of the
`CompiledFunction` returned.

10 files changed, 56 insertions, 268 deletions

diff --git a/ARMeilleure/Translation/ArmEmitterContext.cs b/ARMeilleure/Translation/ArmEmitterContext.cs
index 563775ee..6d02728c 100644
--- a/ARMeilleure/Translation/ArmEmitterContext.cs
+++ b/ARMeilleure/Translation/ArmEmitterContext.cs
@@ -1,3 +1,4 @@
+using ARMeilleure.CodeGen.Linking;
 using ARMeilleure.Common;
 using ARMeilleure.Decoders;
 using ARMeilleure.Diagnostics;
diff --git a/ARMeilleure/Translation/Compiler.cs b/ARMeilleure/Translation/Compiler.cs
index 812144a1..9e4cdb24 100644
--- a/ARMeilleure/Translation/Compiler.cs
+++ b/ARMeilleure/Translation/Compiler.cs
@@ -2,35 +2,16 @@ using ARMeilleure.CodeGen;
 using ARMeilleure.CodeGen.X86;
 using ARMeilleure.Diagnostics;
 using ARMeilleure.IntermediateRepresentation;
-using ARMeilleure.Translation.Cache;
-using ARMeilleure.Translation.PTC;
-using System;
-using System.Runtime.InteropServices;
 
 namespace ARMeilleure.Translation
 {
     static class Compiler
     {
-        public static T Compile<T>(
-            ControlFlowGraph cfg,
-            OperandType[]    argTypes,
-            OperandType      retType,
-            CompilerOptions  options,
-            PtcInfo          ptcInfo = null)
-        {
-            CompiledFunction func = Compile(cfg, argTypes, retType, options, ptcInfo);
-
-            IntPtr codePtr = JitCache.Map(func);
-
-            return Marshal.GetDelegateForFunctionPointer<T>(codePtr);
-        }
-
         public static CompiledFunction Compile(
             ControlFlowGraph cfg,
             OperandType[]    argTypes,
             OperandType      retType,
-            CompilerOptions  options,
-            PtcInfo          ptcInfo = null)
+            CompilerOptions  options)
         {
             Logger.StartPass(PassName.Dominance);
 
@@ -57,7 +38,7 @@ namespace ARMeilleure.Translation
 
             CompilerContext cctx = new(cfg, argTypes, retType, options);
 
-            return CodeGenerator.Generate(cctx, ptcInfo);
+            return CodeGenerator.Generate(cctx);
         }
     }
 }
\ No newline at end of file
diff --git a/ARMeilleure/Translation/CompilerOptions.cs b/ARMeilleure/Translation/CompilerOptions.cs
index 53998ec6..0a07ed4a 100644
--- a/ARMeilleure/Translation/CompilerOptions.cs
+++ b/ARMeilleure/Translation/CompilerOptions.cs
@@ -5,10 +5,11 @@ namespace ARMeilleure.Translation
     [Flags]
     enum CompilerOptions
     {
-        None     = 0,
-        SsaForm  = 1 << 0,
-        Optimize = 1 << 1,
-        Lsra     = 1 << 2,
+        None        = 0,
+        SsaForm     = 1 << 0,
+        Optimize    = 1 << 1,
+        Lsra        = 1 << 2,
+        Relocatable = 1 << 3,
 
         MediumCq = SsaForm | Optimize,
         HighCq   = SsaForm | Optimize | Lsra
diff --git a/ARMeilleure/Translation/PTC/Ptc.cs b/ARMeilleure/Translation/PTC/Ptc.cs
index 8d4f971b..ad2871d0 100644
--- a/ARMeilleure/Translation/PTC/Ptc.cs
+++ b/ARMeilleure/Translation/PTC/Ptc.cs
@@ -1,9 +1,9 @@
 using ARMeilleure.CodeGen;
+using ARMeilleure.CodeGen.Linking;
 using ARMeilleure.CodeGen.Unwinding;
 using ARMeilleure.CodeGen.X86;
 using ARMeilleure.Common;
 using ARMeilleure.Memory;
-using ARMeilleure.Translation.Cache;
 using Ryujinx.Common;
 using Ryujinx.Common.Configuration;
 using Ryujinx.Common.Logging;
@@ -727,15 +727,10 @@ namespace ARMeilleure.Translation.PTC
             UnwindInfo unwindInfo,
             bool highCq)
         {
-            CompiledFunction cFunc = new CompiledFunction(code, unwindInfo);
+            var cFunc = new CompiledFunction(code, unwindInfo, RelocInfo.Empty);
+            var gFunc = cFunc.Map<GuestFunction>();
 
-            IntPtr codePtr = JitCache.Map(cFunc);
-
-            GuestFunction gFunc = Marshal.GetDelegateForFunctionPointer<GuestFunction>(codePtr);
-
-            TranslatedFunction tFunc = new TranslatedFunction(gFunc, callCounter, guestSize, highCq);
-
-            return tFunc;
+            return new TranslatedFunction(gFunc, callCounter, guestSize, highCq);
         }
 
         private static void UpdateInfo(InfoEntry infoEntry)
@@ -889,10 +884,14 @@ namespace ARMeilleure.Translation.PTC
             return XXHash128.ComputeHash(memory.GetSpan(address, checked((int)(guestSize))));
         }
 
-        internal static void WriteInfoCodeRelocUnwindInfo(ulong address, ulong guestSize, Hash128 hash, bool highCq, PtcInfo ptcInfo)
+        internal static void WriteCompiledFunction(ulong address, ulong guestSize, Hash128 hash, bool highCq, CompiledFunction compiledFunc)
         {
             lock (_lock)
             {
+                byte[] code = compiledFunc.Code;
+                RelocInfo relocInfo = compiledFunc.RelocInfo;
+                UnwindInfo unwindInfo = compiledFunc.UnwindInfo;
+
                 InfoEntry infoEntry = new InfoEntry();
 
                 infoEntry.Address = address;
@@ -900,18 +899,37 @@ namespace ARMeilleure.Translation.PTC
                 infoEntry.Hash = hash;
                 infoEntry.HighCq = highCq;
                 infoEntry.Stubbed = false;
-                infoEntry.CodeLength = ptcInfo.Code.Length;
-                infoEntry.RelocEntriesCount = ptcInfo.RelocEntriesCount;
+                infoEntry.CodeLength = code.Length;
+                infoEntry.RelocEntriesCount = relocInfo.Entries.Length;
 
                 SerializeStructure(_infosStream, infoEntry);
 
-                WriteCode(ptcInfo.Code.AsSpan());
+                WriteCode(code.AsSpan());
 
                 // WriteReloc.
-                ptcInfo.RelocStream.WriteTo(_relocsStream);
+                using var relocInfoWriter = new BinaryWriter(_relocsStream, EncodingCache.UTF8NoBOM, true);
+
+                foreach (RelocEntry entry in relocInfo.Entries)
+                {
+                    relocInfoWriter.Write(entry.Position);
+                    relocInfoWriter.Write((byte)entry.Symbol.Type);
+                    relocInfoWriter.Write(entry.Symbol.Value);
+                }
 
                 // WriteUnwindInfo.
-                ptcInfo.UnwindInfoStream.WriteTo(_unwindInfosStream);
+                using var unwindInfoWriter = new BinaryWriter(_unwindInfosStream, EncodingCache.UTF8NoBOM, true);
+
+                unwindInfoWriter.Write(unwindInfo.PushEntries.Length);
+
+                foreach (UnwindPushEntry unwindPushEntry in unwindInfo.PushEntries)
+                {
+                    unwindInfoWriter.Write((int)unwindPushEntry.PseudoOp);
+                    unwindInfoWriter.Write(unwindPushEntry.PrologOffset);
+                    unwindInfoWriter.Write(unwindPushEntry.RegIndex);
+                    unwindInfoWriter.Write(unwindPushEntry.StackOffsetOrAllocSize);
+                }
+
+                unwindInfoWriter.Write(unwindInfo.PrologSize);
             }
         }
 
diff --git a/ARMeilleure/Translation/PTC/PtcInfo.cs b/ARMeilleure/Translation/PTC/PtcInfo.cs
deleted file mode 100644
index b28b2dc1..00000000
--- a/ARMeilleure/Translation/PTC/PtcInfo.cs
+++ /dev/null
@@ -1,63 +0,0 @@
-using ARMeilleure.CodeGen.Unwinding;
-using System;
-using System.IO;
-
-namespace ARMeilleure.Translation.PTC
-{
-    class PtcInfo : IDisposable
-    {
-        private readonly BinaryWriter _relocWriter;
-        private readonly BinaryWriter _unwindInfoWriter;
-
-        public byte[] Code { get; set; }
-
-        public MemoryStream RelocStream      { get; }
-        public MemoryStream UnwindInfoStream { get; }
-
-        public int RelocEntriesCount { get; private set; }
-
-        public PtcInfo()
-        {
-            RelocStream      = new MemoryStream();
-            UnwindInfoStream = new MemoryStream();
-
-            _relocWriter      = new BinaryWriter(RelocStream,      EncodingCache.UTF8NoBOM, true);
-            _unwindInfoWriter = new BinaryWriter(UnwindInfoStream, EncodingCache.UTF8NoBOM, true);
-
-            RelocEntriesCount = 0;
-        }
-
-        public void WriteRelocEntry(RelocEntry relocEntry)
-        {
-            _relocWriter.Write((int)relocEntry.Position);
-            _relocWriter.Write((byte)relocEntry.Symbol.Type);
-            _relocWriter.Write((ulong)relocEntry.Symbol.Value);
-
-            RelocEntriesCount++;
-        }
-
-        public void WriteUnwindInfo(UnwindInfo unwindInfo)
-        {
-            _unwindInfoWriter.Write((int)unwindInfo.PushEntries.Length);
-
-            foreach (UnwindPushEntry unwindPushEntry in unwindInfo.PushEntries)
-            {
-                _unwindInfoWriter.Write((int)unwindPushEntry.PseudoOp);
-                _unwindInfoWriter.Write((int)unwindPushEntry.PrologOffset);
-                _unwindInfoWriter.Write((int)unwindPushEntry.RegIndex);
-                _unwindInfoWriter.Write((int)unwindPushEntry.StackOffsetOrAllocSize);
-            }
-
-            _unwindInfoWriter.Write((int)unwindInfo.PrologSize);
-        }
-
-        public void Dispose()
-        {
-            _relocWriter.Dispose();
-            _unwindInfoWriter.Dispose();
-
-            RelocStream.Dispose();
-            UnwindInfoStream.Dispose();
-        }
-    }
-}
\ No newline at end of file
diff --git a/ARMeilleure/Translation/PTC/RelocEntry.cs b/ARMeilleure/Translation/PTC/RelocEntry.cs
deleted file mode 100644
index 545612d0..00000000
--- a/ARMeilleure/Translation/PTC/RelocEntry.cs
+++ /dev/null
@@ -1,21 +0,0 @@
-namespace ARMeilleure.Translation.PTC
-{
-    struct RelocEntry
-    {
-        public const int Stride = 13; // Bytes.
-
-        public int Position;
-        public Symbol Symbol;
-
-        public RelocEntry(int position, Symbol symbol)
-        {
-            Position = position;
-            Symbol = symbol;
-        }
-
-        public override string ToString()
-        {
-            return $"({nameof(Position)} = {Position}, {nameof(Symbol)} = {Symbol})";
-        }
-    }
-}
\ No newline at end of file
diff --git a/ARMeilleure/Translation/PTC/Symbol.cs b/ARMeilleure/Translation/PTC/Symbol.cs
deleted file mode 100644
index f9d67742..00000000
--- a/ARMeilleure/Translation/PTC/Symbol.cs
+++ /dev/null
@@ -1,100 +0,0 @@
-using System;
-
-namespace ARMeilleure.Translation.PTC
-{
-    /// <summary>
-    /// Represents a symbol.
-    /// </summary>
-    struct Symbol
-    {
-        private readonly ulong _value;
-
-        /// <summary>
-        /// Gets the <see cref="SymbolType"/> of the <see cref="Symbol"/>.
-        /// </summary>
-        public SymbolType Type { get; }
-
-        /// <summary>
-        /// Gets the value of the <see cref="Symbol"/>.
-        /// </summary>
-        /// <exception cref="InvalidOperationException"><see cref="Type"/> is <see cref="SymbolType.None"/></exception>
-        public ulong Value
-        {
-            get
-            {
-                if (Type == SymbolType.None)
-                {
-                    ThrowSymbolNone();
-                }
-
-                return _value;
-            }
-        }
-
-        /// <summary>
-        /// Initializes a new instance of the <see cref="Symbol"/> structure with the specified <see cref="SymbolType"/> and value.
-        /// </summary>
-        /// <param name="type">Type of symbol</param>
-        /// <param name="value">Value of symbol</param>
-        public Symbol(SymbolType type, ulong value)
-        {
-            (Type, _value) = (type, value);
-        }
-
-        /// <summary>
-        /// Determines if the specified <see cref="Symbol"/> instances are equal.
-        /// </summary>
-        /// <param name="a">First instance</param>
-        /// <param name="b">Second instance</param>
-        /// <returns><see langword="true"/> if equal; otherwise <see langword="false"/></returns>
-        public static bool operator ==(Symbol a, Symbol b)
-        {
-            return a.Equals(b);
-        }
-
-        /// <summary>
-        /// Determines if the specified <see cref="Symbol"/> instances are not equal.
-        /// </summary>
-        /// <param name="a">First instance</param>
-        /// <param name="b">Second instance</param>
-        /// <returns><see langword="true"/> if not equal; otherwise <see langword="false"/></returns>
-        /// <inheritdoc/>
-        public static bool operator !=(Symbol a, Symbol b)
-        {
-            return !(a == b);
-        }
-
-        /// <summary>
-        /// Determines if the specified <see cref="Symbol"/> is equal to this <see cref="Symbol"/> instance.
-        /// </summary>
-        /// <param name="other">Other <see cref="Symbol"/> instance</param>
-        /// <returns><see langword="true"/> if equal; otherwise <see langword="false"/></returns>
-        public bool Equals(Symbol other)
-        {
-            return other.Type == Type && other._value == _value;
-        }
-
-        /// <inheritdoc/>
-        public override bool Equals(object obj)
-        {
-            return obj is Symbol sym && Equals(sym);
-        }
-
-        /// <inheritdoc/>
-        public override int GetHashCode()
-        {
-            return HashCode.Combine(Type, _value);
-        }
-
-        /// <inheritdoc/>
-        public override string ToString()
-        {
-            return $"{Type}:{_value}";
-        }
-
-        private static void ThrowSymbolNone()
-        {
-            throw new InvalidOperationException("Symbol refers to nothing.");
-        }
-    }
-}
diff --git a/ARMeilleure/Translation/PTC/SymbolType.cs b/ARMeilleure/Translation/PTC/SymbolType.cs
deleted file mode 100644
index cd7b6c1c..00000000
--- a/ARMeilleure/Translation/PTC/SymbolType.cs
+++ /dev/null
@@ -1,28 +0,0 @@
-namespace ARMeilleure.Translation.PTC
-{
-    /// <summary>
-    /// Types of <see cref="Symbol"/>.
-    /// </summary>
-    enum SymbolType : byte
-    {
-        /// <summary>
-        /// Refers to nothing, i.e no symbol.
-        /// </summary>
-        None,
-
-        /// <summary>
-        /// Refers to an entry in <see cref="Delegates"/>.
-        /// </summary>
-        DelegateTable,
-
-        /// <summary>
-        /// Refers to an entry in <see cref="Translator.FunctionTable"/>.
-        /// </summary>
-        FunctionTable,
-
-        /// <summary>
-        /// Refers to a special symbol which is handled by <see cref="Ptc.PatchCode"/>.
-        /// </summary>
-        Special
-    }
-}
diff --git a/ARMeilleure/Translation/Translator.cs b/ARMeilleure/Translation/Translator.cs
index 03ed4c5e..9974fb2d 100644
--- a/ARMeilleure/Translation/Translator.cs
+++ b/ARMeilleure/Translation/Translator.cs
@@ -1,3 +1,4 @@
+using ARMeilleure.CodeGen;
 using ARMeilleure.Common;
 using ARMeilleure.Decoders;
 using ARMeilleure.Diagnostics;
@@ -279,32 +280,30 @@ namespace ARMeilleure.Translation
 
             Logger.EndPass(PassName.RegisterUsage);
 
-            OperandType[] argTypes = new OperandType[] { OperandType.I64 };
+            var retType = OperandType.I64;
+            var argTypes = new OperandType[] { OperandType.I64 };
 
-            CompilerOptions options = highCq ? CompilerOptions.HighCq : CompilerOptions.None;
+            var options = highCq ? CompilerOptions.HighCq : CompilerOptions.None;
 
-            GuestFunction func;
-
-            if (!context.HasPtc)
+            if (context.HasPtc)
             {
-                func = Compiler.Compile<GuestFunction>(cfg, argTypes, OperandType.I64, options);
+                options |= CompilerOptions.Relocatable;
             }
-            else
-            {
-                using PtcInfo ptcInfo = new PtcInfo();
 
-                func = Compiler.Compile<GuestFunction>(cfg, argTypes, OperandType.I64, options, ptcInfo);
+            CompiledFunction compiledFunc = Compiler.Compile(cfg, argTypes, retType, options);
 
+            if (context.HasPtc)
+            {
                 Hash128 hash = Ptc.ComputeHash(Memory, address, funcSize);
 
-                Ptc.WriteInfoCodeRelocUnwindInfo(address, funcSize, hash, highCq, ptcInfo);
+                Ptc.WriteCompiledFunction(address, funcSize, hash, highCq, compiledFunc);
             }
 
-            var result = new TranslatedFunction(func, counter, funcSize, highCq);
+            GuestFunction func = compiledFunc.Map<GuestFunction>();
 
             Allocators.ResetAll();
 
-            return result;
+            return new TranslatedFunction(func, counter, funcSize, highCq);
         }
 
         private struct Range
diff --git a/ARMeilleure/Translation/TranslatorStubs.cs b/ARMeilleure/Translation/TranslatorStubs.cs
index 48fa3a94..4ad6c2f2 100644
--- a/ARMeilleure/Translation/TranslatorStubs.cs
+++ b/ARMeilleure/Translation/TranslatorStubs.cs
@@ -178,7 +178,7 @@ namespace ARMeilleure.Translation
             var retType = OperandType.I64;
             var argTypes = new[] { OperandType.I64 };
 
-            var func = Compiler.Compile<GuestFunction>(cfg, argTypes, retType, CompilerOptions.HighCq);
+            var func = Compiler.Compile(cfg, argTypes, retType, CompilerOptions.HighCq).Map<GuestFunction>();
 
             return Marshal.GetFunctionPointerForDelegate(func);
         }
@@ -204,7 +204,7 @@ namespace ARMeilleure.Translation
             var retType = OperandType.I64;
             var argTypes = new[] { OperandType.I64 };
 
-            var func = Compiler.Compile<GuestFunction>(cfg, argTypes, retType, CompilerOptions.HighCq);
+            var func = Compiler.Compile(cfg, argTypes, retType, CompilerOptions.HighCq).Map<GuestFunction>();
 
             return Marshal.GetFunctionPointerForDelegate(func);
         }
@@ -242,7 +242,7 @@ namespace ARMeilleure.Translation
             var retType = OperandType.None;
             var argTypes = new[] { OperandType.I64, OperandType.I64 };
 
-            return Compiler.Compile<DispatcherFunction>(cfg, argTypes, retType, CompilerOptions.HighCq);
+            return Compiler.Compile(cfg, argTypes, retType, CompilerOptions.HighCq).Map<DispatcherFunction>();
         }
     }
 }