blob: 7db321f315b976772645ee879318f9abe1011489 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
|
using Mono.Cecil.Cil;
using Mono.Cecil.Rocks;
using System;
using System.Linq;
using System.Collections.Generic;
namespace Xamarin.Forms.Build.Tasks
{
static class MethodBodyExtensions
{
public static void Optimize(this MethodBody self)
{
if (self == null)
throw new ArgumentNullException(nameof(self));
self.OptimizeLongs();
self.OptimizeStLdLoc();
self.RemoveUnusedLocals();
self.OptimizeMacros();
}
static void ExpandMacro(Instruction instruction, OpCode opcode, object operand)
{
instruction.OpCode = opcode;
instruction.Operand = operand;
}
//this can be removed if/when https://github.com/jbevain/cecil/pull/307 is released in a nuget we consume
static void OptimizeLongs(this MethodBody self)
{
for (var i = 0; i < self.Instructions.Count; i++) {
var instruction = self.Instructions[i];
if (instruction.OpCode.Code != Code.Ldc_I8)
continue;
var l = (long)instruction.Operand;
if (l < int.MinValue || l > int.MaxValue)
continue;
ExpandMacro(instruction, OpCodes.Ldc_I4, unchecked((int)l));
self.Instructions.Insert(++i, Instruction.Create(OpCodes.Conv_I8));
}
}
static void OptimizeStLdLoc(this MethodBody self)
{
var method = self.Method;
for (var i = 0; i < self.Instructions.Count; i++) {
var instruction = self.Instructions[i];
if (instruction.OpCode.Code != Code.Stloc)
continue;
if (i + 1 >= self.Instructions.Count)
continue;
var next = self.Instructions[i + 1];
int num = ((VariableDefinition)instruction.Operand).Index;
var vardef = instruction.Operand;
if (next.OpCode.Code != Code.Ldloc || num != ((VariableDefinition)next.Operand).Index)
continue;
ExpandMacro(instruction, OpCodes.Dup, null);
ExpandMacro(next, OpCodes.Stloc, vardef);
}
}
static void RemoveUnusedLocals(this MethodBody self)
{
//Count ldloc for each variable
var ldlocUsed = new List<VariableDefinition>();
foreach (var instruction in self.Instructions) {
if (instruction.OpCode.Code != Code.Ldloc)
continue;
var varDef = (VariableDefinition)instruction.Operand;
if (!ldlocUsed.Contains(varDef))
ldlocUsed.Add(varDef);
}
foreach (var varDef in self.Variables.ToArray()) {
if (ldlocUsed.Contains(varDef))
continue;
//find the Stloc instruction
var instruction = (from instr in self.Instructions where instr.OpCode.Code == Code.Stloc && instr.Operand == varDef select instr).First();
//remove dup/stloc
if (instruction.Previous.OpCode.Code != Code.Dup)
break;
self.Instructions.Remove(instruction.Previous);
self.Instructions.Remove(instruction);
//and remove the variable
self.Variables.Remove(varDef);
}
}
}
}
|
