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.

1 files changed, 16 insertions, 17 deletions

diff --git a/ARMeilleure/CodeGen/X86/Assembler.cs b/ARMeilleure/CodeGen/X86/Assembler.cs
index 044f6047..95608756 100644
--- a/ARMeilleure/CodeGen/X86/Assembler.cs
+++ b/ARMeilleure/CodeGen/X86/Assembler.cs
@@ -1,6 +1,7 @@
+using ARMeilleure.CodeGen.Linking;
 using ARMeilleure.IntermediateRepresentation;
-using ARMeilleure.Translation.PTC;
 using System;
+using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
 
@@ -61,12 +62,12 @@ namespace ARMeilleure.CodeGen.X86
             }
         }
 
-        private static InstructionInfo[] _instTable;
+        private readonly static InstructionInfo[] _instTable;
 
-        private Stream _stream;
+        private readonly Stream _stream;
 
-        private PtcInfo _ptcInfo;
-        private bool    _ptcDisabled;
+        public List<RelocEntry> Relocs { get; }
+        public bool HasRelocs => Relocs != null;
 
         static Assembler()
         {
@@ -294,12 +295,10 @@ namespace ARMeilleure.CodeGen.X86
             _instTable[(int)inst] = info;
         }
 
-        public Assembler(Stream stream, PtcInfo ptcInfo = null)
+        public Assembler(Stream stream, bool relocatable)
         {
             _stream = stream;
-
-            _ptcInfo     = ptcInfo;
-            _ptcDisabled = ptcInfo == null;
+            Relocs = relocatable ? new List<RelocEntry>() : null;
         }
 
         public void Add(Operand dest, Operand source, OperandType type)
@@ -498,7 +497,7 @@ namespace ARMeilleure.CodeGen.X86
 
         public void Jcc(X86Condition condition, long offset)
         {
-            if (_ptcDisabled && ConstFitsOnS8(offset))
+            if (!HasRelocs && ConstFitsOnS8(offset))
             {
                 WriteByte((byte)(0x70 | (int)condition));
 
@@ -519,7 +518,7 @@ namespace ARMeilleure.CodeGen.X86
 
         public void Jmp(long offset)
         {
-            if (_ptcDisabled && ConstFitsOnS8(offset))
+            if (!HasRelocs && ConstFitsOnS8(offset))
             {
                 WriteByte(0xeb);
 
@@ -980,9 +979,9 @@ namespace ARMeilleure.CodeGen.X86
 
                         WriteByte((byte)(info.OpRImm64 + (dest.GetRegister().Index & 0b111)));
 
-                        if (_ptcInfo != default && source.Relocatable)
+                        if (HasRelocs && source.Relocatable)
                         {
-                            _ptcInfo.WriteRelocEntry(new RelocEntry((int)_stream.Position, source.Symbol));
+                            Relocs.Add(new RelocEntry((int)_stream.Position, source.Symbol));
                         }
 
                         WriteUInt64(imm);
@@ -1396,9 +1395,9 @@ namespace ARMeilleure.CodeGen.X86
             return ConstFitsOnS32(value);
         }
 
-        public static int GetJccLength(long offset, bool ptcDisabled = true)
+        public static int GetJccLength(long offset, bool relocatable = false)
         {
-            if (ptcDisabled && ConstFitsOnS8(offset < 0 ? offset - 2 : offset))
+            if (!relocatable && ConstFitsOnS8(offset < 0 ? offset - 2 : offset))
             {
                 return 2;
             }
@@ -1412,9 +1411,9 @@ namespace ARMeilleure.CodeGen.X86
             }
         }
 
-        public static int GetJmpLength(long offset, bool ptcDisabled = true)
+        public static int GetJmpLength(long offset, bool relocatable = false)
         {
-            if (ptcDisabled && ConstFitsOnS8(offset < 0 ? offset - 2 : offset))
+            if (!relocatable && ConstFitsOnS8(offset < 0 ? offset - 2 : offset))
             {
                 return 2;
             }