src/Tizen.NUI.XamlBuild/src/public/XamlBuild/MethodBodyExtensions.cs

   1 using Mono.Cecil.Cil;
   2 using Mono.Cecil.Rocks;
   3 using System;
   4 using System.Linq;
   5 using System.Collections.Generic;
   6
   7 namespace Tizen.NUI.Xaml.Build.Tasks
   8 {
   9     static class MethodBodyExtensions
  10     {
  11         public static void Optimize(this MethodBody self)
  12         {
  13             if (self == null)
  14                 throw new ArgumentNullException(nameof(self));
  15
  16             self.OptimizeLongs();
  17             self.OptimizeStLdLoc();
  18             self.RemoveUnusedLocals();
  19             self.OptimizeMacros();
  20         }
  21
  22         static void ExpandMacro(Instruction instruction, OpCode opcode, object operand)
  23         {
  24             instruction.OpCode = opcode;
  25             instruction.Operand = operand;
  26         }
  27
  28         //this can be removed if/when https://github.com/jbevain/cecil/pull/307 is released in a nuget we consume
  29         static void OptimizeLongs(this MethodBody self)
  30         {
  31             for (var i = 0; i < self.Instructions.Count; i++) {
  32                 var instruction = self.Instructions[i];
  33                 if (instruction.OpCode.Code != Code.Ldc_I8)
  34                     continue;
  35                 var l = (long)instruction.Operand;
  36                 if (l < int.MinValue || l > int.MaxValue)
  37                     continue;
  38                 ExpandMacro(instruction, OpCodes.Ldc_I4, unchecked((int)l));
  39                 self.Instructions.Insert(++i, Instruction.Create(OpCodes.Conv_I8));
  40             }
  41         }
  42
  43         static void OptimizeStLdLoc(this MethodBody self)
  44         {
  45             var method = self.Method;
  46             for (var i = 0; i < self.Instructions.Count; i++) {
  47                 var instruction = self.Instructions[i];
  48                 if (instruction.OpCode.Code != Code.Stloc)
  49                     continue;
  50                 if (i + 1 >= self.Instructions.Count)
  51                     continue;
  52                 var next = self.Instructions[i + 1];
  53                 int num = ((VariableDefinition)instruction.Operand).Index;
  54                 var vardef = instruction.Operand;
  55                 if (next.OpCode.Code != Code.Ldloc || num != ((VariableDefinition)next.Operand).Index)
  56                     continue;
  57                 ExpandMacro(instruction, OpCodes.Dup, null);
  58                 ExpandMacro(next, OpCodes.Stloc, vardef);
  59             }
  60         }
  61
  62         static void RemoveUnusedLocals(this MethodBody self)
  63         {
  64             //Count ldloc for each variable
  65             var ldlocUsed = new List<VariableDefinition>();
  66             foreach (var instruction in self.Instructions) {
  67                 if (instruction.OpCode.Code != Code.Ldloc)
  68                     continue;
  69                 var varDef = (VariableDefinition)instruction.Operand;
  70                 if (!ldlocUsed.Contains(varDef))
  71                     ldlocUsed.Add(varDef);
  72             }
  73
  74             foreach (var varDef in self.Variables.ToArray()) {
  75                 if (ldlocUsed.Contains(varDef))
  76                     continue;
  77
  78                 //find the Stloc instruction
  79                 var instruction = (from instr in self.Instructions where instr.OpCode.Code == Code.Stloc && instr.Operand == varDef select instr).First();
  80
  81                 //remove dup/stloc
  82                 if (instruction.Previous.OpCode.Code != Code.Dup)
  83                     break;
  84
  85                 self.Instructions.Remove(instruction.Previous);
  86                 self.Instructions.Remove(instruction);
  87
  88                 //and remove the variable
  89                 self.Variables.Remove(varDef);
  90             }
  91         }
  92     }
  93 }