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
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
|
package transform
import (
"errors"
"fmt"
"go/token"
"os"
"github.com/tinygo-org/tinygo/compileopts"
"github.com/tinygo-org/tinygo/compiler/ircheck"
"tinygo.org/x/go-llvm"
)
// OptimizePackage runs optimization passes over the LLVM module for the given
// Go package.
func OptimizePackage(mod llvm.Module, config *compileopts.Config) {
optLevel, sizeLevel, _ := config.OptLevels()
// Run function passes for each function in the module.
// These passes are intended to be run on each function right
// after they're created to reduce IR size (and maybe also for
// cache locality to improve performance), but for now they're
// run here for each function in turn. Maybe this can be
// improved in the future.
builder := llvm.NewPassManagerBuilder()
defer builder.Dispose()
builder.SetOptLevel(optLevel)
builder.SetSizeLevel(sizeLevel)
funcPasses := llvm.NewFunctionPassManagerForModule(mod)
defer funcPasses.Dispose()
builder.PopulateFunc(funcPasses)
funcPasses.InitializeFunc()
for fn := mod.FirstFunction(); !fn.IsNil(); fn = llvm.NextFunction(fn) {
if fn.IsDeclaration() {
continue
}
funcPasses.RunFunc(fn)
}
funcPasses.FinalizeFunc()
// Run TinyGo-specific optimization passes.
if optLevel > 0 {
OptimizeMaps(mod)
}
}
// Optimize runs a number of optimization and transformation passes over the
// given module. Some passes are specific to TinyGo, others are generic LLVM
// passes. You can set a preferred performance (0-3) and size (0-2) level and
// control the limits of the inliner (higher numbers mean more inlining, set it
// to 0 to disable entirely).
//
// Please note that some optimizations are not optional, thus Optimize must
// alwasy be run before emitting machine code. Set all controls (optLevel,
// sizeLevel, inlinerThreshold) to 0 to reduce the number of optimizations to a
// minimum.
func Optimize(mod llvm.Module, config *compileopts.Config, optLevel, sizeLevel int, inlinerThreshold uint) []error {
builder := llvm.NewPassManagerBuilder()
defer builder.Dispose()
builder.SetOptLevel(optLevel)
builder.SetSizeLevel(sizeLevel)
if inlinerThreshold != 0 {
builder.UseInlinerWithThreshold(inlinerThreshold)
}
// Make sure these functions are kept in tact during TinyGo transformation passes.
for _, name := range functionsUsedInTransforms {
fn := mod.NamedFunction(name)
if fn.IsNil() {
panic(fmt.Errorf("missing core function %q", name))
}
fn.SetLinkage(llvm.ExternalLinkage)
}
if config.PanicStrategy() == "trap" {
ReplacePanicsWithTrap(mod) // -panic=trap
}
// run a check of all of our code
if config.VerifyIR() {
errs := ircheck.Module(mod)
if errs != nil {
return errs
}
}
if optLevel > 0 {
// Run some preparatory passes for the Go optimizer.
goPasses := llvm.NewPassManager()
defer goPasses.Dispose()
goPasses.AddGlobalDCEPass()
goPasses.AddGlobalOptimizerPass()
goPasses.AddIPSCCPPass()
goPasses.AddInstructionCombiningPass() // necessary for OptimizeReflectImplements
goPasses.AddAggressiveDCEPass()
goPasses.AddFunctionAttrsPass()
goPasses.Run(mod)
// Run TinyGo-specific optimization passes.
OptimizeStringToBytes(mod)
OptimizeReflectImplements(mod)
OptimizeAllocs(mod, nil, nil)
err := LowerInterfaces(mod, config)
if err != nil {
return []error{err}
}
errs := LowerInterrupts(mod)
if len(errs) > 0 {
return errs
}
// After interfaces are lowered, there are many more opportunities for
// interprocedural optimizations. To get them to work, function
// attributes have to be updated first.
goPasses.Run(mod)
// Run TinyGo-specific interprocedural optimizations.
OptimizeAllocs(mod, config.Options.PrintAllocs, func(pos token.Position, msg string) {
fmt.Fprintln(os.Stderr, pos.String()+": "+msg)
})
OptimizeStringToBytes(mod)
OptimizeStringEqual(mod)
} else {
// Must be run at any optimization level.
err := LowerInterfaces(mod, config)
if err != nil {
return []error{err}
}
errs := LowerInterrupts(mod)
if len(errs) > 0 {
return errs
}
// Clean up some leftover symbols of the previous transformations.
goPasses := llvm.NewPassManager()
defer goPasses.Dispose()
goPasses.AddGlobalDCEPass()
goPasses.Run(mod)
}
if config.Scheduler() == "none" {
// Check for any goroutine starts.
if start := mod.NamedFunction("internal/task.start"); !start.IsNil() && len(getUses(start)) > 0 {
errs := []error{}
for _, call := range getUses(start) {
errs = append(errs, errorAt(call, "attempted to start a goroutine without a scheduler"))
}
return errs
}
}
if config.VerifyIR() {
if errs := ircheck.Module(mod); errs != nil {
return errs
}
}
if err := llvm.VerifyModule(mod, llvm.PrintMessageAction); err != nil {
return []error{errors.New("optimizations caused a verification failure")}
}
// After TinyGo-specific transforms have finished, undo exporting these functions.
for _, name := range functionsUsedInTransforms {
fn := mod.NamedFunction(name)
if fn.IsNil() || fn.IsDeclaration() {
continue
}
fn.SetLinkage(llvm.InternalLinkage)
}
// Run function passes again, because without it, llvm.coro.size.i32()
// doesn't get lowered.
funcPasses := llvm.NewFunctionPassManagerForModule(mod)
defer funcPasses.Dispose()
builder.PopulateFunc(funcPasses)
funcPasses.InitializeFunc()
for fn := mod.FirstFunction(); !fn.IsNil(); fn = llvm.NextFunction(fn) {
funcPasses.RunFunc(fn)
}
funcPasses.FinalizeFunc()
// Run module passes.
// TODO: somehow set the PrepareForThinLTO flag in the pass manager builder.
modPasses := llvm.NewPassManager()
defer modPasses.Dispose()
builder.Populate(modPasses)
modPasses.Run(mod)
hasGCPass := MakeGCStackSlots(mod)
if hasGCPass {
if err := llvm.VerifyModule(mod, llvm.PrintMessageAction); err != nil {
return []error{errors.New("GC pass caused a verification failure")}
}
}
return nil
}
// functionsUsedInTransform is a list of function symbols that may be used
// during TinyGo optimization passes so they have to be marked as external
// linkage until all TinyGo passes have finished.
var functionsUsedInTransforms = []string{
"runtime.alloc",
"runtime.free",
"runtime.nilPanic",
}
|
