1 // Copyright 2023 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
8 "cmd/compile/internal/base"
9 "cmd/compile/internal/ir"
10 "cmd/compile/internal/types"
13 "internal/goexperiment"
22 debugTraceFuncs = 1 << iota
26 debugTraceExprClassify
31 // propAnalyzer interface is used for defining one or more analyzer
32 // helper objects, each tasked with computing some specific subset of
33 // the properties we're interested in. The assumption is that
34 // properties are independent, so each new analyzer that implements
35 // this interface can operate entirely on its own. For a given analyzer
36 // there will be a sequence of calls to nodeVisitPre and nodeVisitPost
37 // as the nodes within a function are visited, then a followup call to
38 // setResults so that the analyzer can transfer its results into the
39 // final properties object.
40 type propAnalyzer interface {
41 nodeVisitPre(n ir.Node)
42 nodeVisitPost(n ir.Node)
43 setResults(funcProps *FuncProps)
46 // fnInlHeur contains inline heuristics state information about a
47 // specific Go function being analyzed/considered by the inliner. Note
48 // that in addition to constructing a fnInlHeur object by analyzing a
49 // specific *ir.Func, there is also code in the test harness
50 // (funcprops_test.go) that builds up fnInlHeur's by reading in and
51 // parsing a dump. This is the reason why we have file/fname/line
52 // fields below instead of just an *ir.Func field.
53 type fnInlHeur struct {
62 var fpmap = map[*ir.Func]fnInlHeur{}
64 func AnalyzeFunc(fn *ir.Func, canInline func(*ir.Func), inlineMaxBudget int32) *FuncProps {
65 if funcInlHeur, ok := fpmap[fn]; ok {
66 return funcInlHeur.props
68 funcProps, fcstab := computeFuncProps(fn, canInline, inlineMaxBudget)
69 file, line := fnFileLine(fn)
74 inlineMaxBudget: inlineMaxBudget,
78 fn.SetNeverReturns(entry.props.Flags&FuncPropNeverReturns != 0)
80 if fn.Inl != nil && fn.Inl.Properties == "" {
81 fn.Inl.Properties = entry.props.SerializeToString()
86 // RevisitInlinability revisits the question of whether to continue to
87 // treat function 'fn' as an inline candidate based on the set of
88 // properties we've computed for it. If (for example) it has an
89 // initial size score of 150 and no interesting properties to speak
90 // of, then there isn't really any point to moving ahead with it as an
92 func RevisitInlinability(fn *ir.Func, budgetForFunc func(*ir.Func) int32) {
96 entry, ok := fpmap[fn]
101 mxAdjust := int32(largestScoreAdjustment(fn, entry.props))
102 budget := budgetForFunc(fn)
103 if fn.Inl.Cost+mxAdjust > budget {
108 // computeFuncProps examines the Go function 'fn' and computes for it
109 // a function "properties" object, to be used to drive inlining
110 // heuristics. See comments on the FuncProps type for more info.
111 func computeFuncProps(fn *ir.Func, canInline func(*ir.Func), inlineMaxBudget int32) (*FuncProps, CallSiteTab) {
112 enableDebugTraceIfEnv()
113 if debugTrace&debugTraceFuncs != 0 {
114 fmt.Fprintf(os.Stderr, "=-= starting analysis of func %v:\n%+v\n",
117 ra := makeResultsAnalyzer(fn, canInline, inlineMaxBudget)
118 pa := makeParamsAnalyzer(fn)
119 ffa := makeFuncFlagsAnalyzer(fn)
120 analyzers := []propAnalyzer{ffa, ra, pa}
121 funcProps := new(FuncProps)
122 runAnalyzersOnFunction(fn, analyzers)
123 for _, a := range analyzers {
124 a.setResults(funcProps)
126 // Now build up a partial table of callsites for this func.
127 if debugTrace&debugTraceCalls != 0 {
128 fmt.Fprintf(os.Stderr, "=-= making callsite table for func %v:\n", fn)
130 cstab := computeCallSiteTable(fn, fn.Body, ffa.panicPathTable(), 0)
132 return funcProps, cstab
135 func runAnalyzersOnFunction(fn *ir.Func, analyzers []propAnalyzer) {
136 var doNode func(ir.Node) bool
137 doNode = func(n ir.Node) bool {
138 for _, a := range analyzers {
141 ir.DoChildren(n, doNode)
142 for _, a := range analyzers {
150 func propsForFunc(fn *ir.Func) *FuncProps {
151 if funcInlHeur, ok := fpmap[fn]; ok {
152 return funcInlHeur.props
153 } else if fn.Inl != nil && fn.Inl.Properties != "" {
154 // FIXME: considering adding some sort of cache or table
155 // for deserialized properties of imported functions.
156 return DeserializeFromString(fn.Inl.Properties)
161 func fnFileLine(fn *ir.Func) (string, uint) {
162 p := base.Ctxt.InnermostPos(fn.Pos())
163 return filepath.Base(p.Filename()), p.Line()
166 func UnitTesting() bool {
167 return base.Debug.DumpInlFuncProps != ""
170 // DumpFuncProps computes and caches function properties for the func
171 // 'fn' and any closures it contains, or if fn is nil, it writes out the
172 // cached set of properties to the file given in 'dumpfile'. Used for
173 // the "-d=dumpinlfuncprops=..." command line flag, intended for use
174 // primarily in unit testing.
175 func DumpFuncProps(fn *ir.Func, dumpfile string, canInline func(*ir.Func), inlineMaxBudget int32) {
177 enableDebugTraceIfEnv()
178 dmp := func(fn *ir.Func) {
179 if !goexperiment.NewInliner {
182 captureFuncDumpEntry(fn, canInline, inlineMaxBudget)
185 ir.Visit(fn, func(n ir.Node) {
186 if clo, ok := n.(*ir.ClosureExpr); ok {
192 emitDumpToFile(dumpfile)
196 // emitDumpToFile writes out the buffer function property dump entries
197 // to a file, for unit testing. Dump entries need to be sorted by
198 // definition line, and due to generics we need to account for the
199 // possibility that several ir.Func's will have the same def line.
200 func emitDumpToFile(dumpfile string) {
201 mode := os.O_WRONLY | os.O_CREATE | os.O_TRUNC
202 if dumpfile[0] == '+' {
203 dumpfile = dumpfile[1:]
204 mode = os.O_WRONLY | os.O_APPEND | os.O_CREATE
206 if dumpfile[0] == '%' {
207 dumpfile = dumpfile[1:]
208 d, b := filepath.Dir(dumpfile), filepath.Base(dumpfile)
209 ptag := strings.ReplaceAll(types.LocalPkg.Path, "/", ":")
210 dumpfile = d + "/" + ptag + "." + b
212 outf, err := os.OpenFile(dumpfile, mode, 0644)
214 base.Fatalf("opening function props dump file %q: %v\n", dumpfile, err)
217 dumpFilePreamble(outf)
219 atline := map[uint]uint{}
220 sl := make([]fnInlHeur, 0, len(dumpBuffer))
221 for _, e := range dumpBuffer {
223 atline[e.line] = atline[e.line] + 1
225 sl = sortFnInlHeurSlice(sl)
228 for _, entry := range sl {
230 if prevline == entry.line {
233 prevline = entry.line
234 atl := atline[entry.line]
235 if err := dumpFnPreamble(outf, &entry, nil, idx, atl); err != nil {
236 base.Fatalf("function props dump: %v\n", err)
242 // captureFuncDumpEntry grabs the function properties object for 'fn'
243 // and enqueues it for later dumping. Used for the
244 // "-d=dumpinlfuncprops=..." command line flag, intended for use
245 // primarily in unit testing.
246 func captureFuncDumpEntry(fn *ir.Func, canInline func(*ir.Func), inlineMaxBudget int32) {
247 // avoid capturing compiler-generated equality funcs.
248 if strings.HasPrefix(fn.Sym().Name, ".eq.") {
251 funcInlHeur, ok := fpmap[fn]
252 // Props object should already be present, unless this is a
253 // directly recursive routine.
255 AnalyzeFunc(fn, canInline, inlineMaxBudget)
256 funcInlHeur = fpmap[fn]
257 if fn.Inl != nil && fn.Inl.Properties == "" {
258 fn.Inl.Properties = funcInlHeur.props.SerializeToString()
261 if dumpBuffer == nil {
262 dumpBuffer = make(map[*ir.Func]fnInlHeur)
264 if _, ok := dumpBuffer[fn]; ok {
265 // we can wind up seeing closures multiple times here,
266 // so don't add them more than once.
269 if debugTrace&debugTraceFuncs != 0 {
270 fmt.Fprintf(os.Stderr, "=-= capturing dump for %v:\n", fn)
272 dumpBuffer[fn] = funcInlHeur
275 // dumpFilePreamble writes out a file-level preamble for a given
276 // Go function as part of a function properties dump.
277 func dumpFilePreamble(w io.Writer) {
278 fmt.Fprintf(w, "// DO NOT EDIT (use 'go test -v -update-expected' instead.)\n")
279 fmt.Fprintf(w, "// See cmd/compile/internal/inline/inlheur/testdata/props/README.txt\n")
280 fmt.Fprintf(w, "// for more information on the format of this file.\n")
281 fmt.Fprintf(w, "// %s\n", preambleDelimiter)
284 // dumpFnPreamble writes out a function-level preamble for a given
285 // Go function as part of a function properties dump. See the
286 // README.txt file in testdata/props for more on the format of
288 func dumpFnPreamble(w io.Writer, funcInlHeur *fnInlHeur, ecst encodedCallSiteTab, idx, atl uint) error {
289 fmt.Fprintf(w, "// %s %s %d %d %d\n",
290 funcInlHeur.file, funcInlHeur.fname, funcInlHeur.line, idx, atl)
291 // emit props as comments, followed by delimiter
292 fmt.Fprintf(w, "%s// %s\n", funcInlHeur.props.ToString("// "), comDelimiter)
293 data, err := json.Marshal(funcInlHeur.props)
295 return fmt.Errorf("marshall error %v\n", err)
297 fmt.Fprintf(w, "// %s\n", string(data))
298 dumpCallSiteComments(w, funcInlHeur.cstab, ecst)
299 fmt.Fprintf(w, "// %s\n", fnDelimiter)
303 // sortFnInlHeurSlice sorts a slice of fnInlHeur based on
304 // the starting line of the function definition, then by name.
305 func sortFnInlHeurSlice(sl []fnInlHeur) []fnInlHeur {
306 sort.SliceStable(sl, func(i, j int) bool {
307 if sl[i].line != sl[j].line {
308 return sl[i].line < sl[j].line
310 return sl[i].fname < sl[j].fname
315 // delimiters written to various preambles to make parsing of
317 const preambleDelimiter = "<endfilepreamble>"
318 const fnDelimiter = "<endfuncpreamble>"
319 const comDelimiter = "<endpropsdump>"
320 const csDelimiter = "<endcallsites>"
322 // dumpBuffer stores up function properties dumps when
323 // "-d=dumpinlfuncprops=..." is in effect.
324 var dumpBuffer map[*ir.Func]fnInlHeur