/
stdlib_test.go
195 lines (167 loc) · 5.57 KB
/
stdlib_test.go
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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Incomplete source tree on Android.
//go:build !android
// +build !android
package ssa_test
// This file runs the SSA builder in sanity-checking mode on all
// packages beneath $GOROOT and prints some summary information.
//
// Run with "go test -cpu=8 to" set GOMAXPROCS.
import (
"go/ast"
"go/token"
"go/types"
"runtime"
"testing"
"time"
"golang.org/x/tools/go/packages"
"golang.org/x/tools/go/ssa"
"golang.org/x/tools/go/ssa/ssautil"
"golang.org/x/tools/internal/testenv"
)
func bytesAllocated() uint64 {
runtime.GC()
var stats runtime.MemStats
runtime.ReadMemStats(&stats)
return stats.Alloc
}
// TestStdlib loads the entire standard library and its tools.
//
// Apart from a small number of internal packages that are not
// returned by the 'std' query, the set is essentially transitively
// closed, so marginal per-dependency costs are invisible.
func TestStdlib(t *testing.T) {
testLoad(t, 500, "std", "cmd")
}
// TestNetHTTP builds a single SSA package but not its dependencies.
// It may help reveal costs related to dependencies (e.g. unnecessary building).
func TestNetHTTP(t *testing.T) {
testLoad(t, 120, "net/http")
}
func testLoad(t *testing.T, minPkgs int, patterns ...string) {
// Note: most of the commentary below applies to TestStdlib.
if testing.Short() {
t.Skip("skipping in short mode; too slow (https://golang.org/issue/14113)") // ~5s
}
testenv.NeedsTool(t, "go")
// Load, parse and type-check the program.
t0 := time.Now()
alloc0 := bytesAllocated()
cfg := &packages.Config{Mode: packages.LoadSyntax}
pkgs, err := packages.Load(cfg, patterns...)
if err != nil {
t.Fatal(err)
}
t1 := time.Now()
alloc1 := bytesAllocated()
// Create SSA packages.
var mode ssa.BuilderMode
// Comment out these lines during benchmarking. Approx SSA build costs are noted.
mode |= ssa.SanityCheckFunctions // + 2% space, + 4% time
mode |= ssa.GlobalDebug // +30% space, +18% time
mode |= ssa.InstantiateGenerics // + 0% space, + 2% time (unlikely to reproduce outside of stdlib)
prog, _ := ssautil.Packages(pkgs, mode)
t2 := time.Now()
// Build SSA.
prog.Build()
t3 := time.Now()
alloc3 := bytesAllocated()
// Sanity check to ensure we haven't dropped large numbers of packages.
numPkgs := len(prog.AllPackages())
if numPkgs < minPkgs {
t.Errorf("Loaded only %d packages, want at least %d", numPkgs, minPkgs)
}
// Keep pkgs reachable until after we've measured memory usage.
if len(pkgs) == 0 {
panic("unreachable")
}
srcFuncs := srcFunctions(prog, pkgs)
allFuncs := ssautil.AllFunctions(prog)
// The assertion below is not valid if the program contains
// variants of the same package, such as the test variants
// (e.g. package p as compiled for test executable x) obtained
// when cfg.Tests=true. Profile-guided optimization may
// lead to similar variation for non-test executables.
//
// Ideally, the test would assert that all functions within
// each executable (more generally: within any singly rooted
// transitively closed subgraph of the import graph) have
// distinct names, but that isn't so easy to compute efficiently.
// Disabling for now.
if false {
// Check that all non-synthetic functions have distinct names.
// Synthetic wrappers for exported methods should be distinct too,
// except for unexported ones (explained at (*Function).RelString).
byName := make(map[string]*ssa.Function)
for fn := range allFuncs {
if fn.Synthetic == "" || ast.IsExported(fn.Name()) {
str := fn.String()
prev := byName[str]
byName[str] = fn
if prev != nil {
t.Errorf("%s: duplicate function named %s",
prog.Fset.Position(fn.Pos()), str)
t.Errorf("%s: (previously defined here)",
prog.Fset.Position(prev.Pos()))
}
}
}
}
// Dump some statistics.
var numInstrs int
for fn := range allFuncs {
for _, b := range fn.Blocks {
numInstrs += len(b.Instrs)
}
}
// determine line count
var lineCount int
prog.Fset.Iterate(func(f *token.File) bool {
lineCount += f.LineCount()
return true
})
// NB: when benchmarking, don't forget to clear the debug +
// sanity builder flags for better performance.
t.Log("GOMAXPROCS: ", runtime.GOMAXPROCS(0))
t.Log("#Source lines: ", lineCount)
t.Log("Load/parse/typecheck: ", t1.Sub(t0))
t.Log("SSA create: ", t2.Sub(t1))
t.Log("SSA build: ", t3.Sub(t2))
// SSA stats:
t.Log("#Packages: ", numPkgs)
t.Log("#SrcFunctions: ", len(srcFuncs))
t.Log("#AllFunctions: ", len(allFuncs))
t.Log("#Instructions: ", numInstrs)
t.Log("#MB AST+types: ", int64(alloc1-alloc0)/1e6)
t.Log("#MB SSA: ", int64(alloc3-alloc1)/1e6)
}
// srcFunctions gathers all ssa.Functions corresponding to syntax.
// (Includes generics but excludes instances and all wrappers.)
//
// This is essentially identical to the SrcFunctions logic in
// go/analysis/passes/buildssa.
func srcFunctions(prog *ssa.Program, pkgs []*packages.Package) (res []*ssa.Function) {
var addSrcFunc func(fn *ssa.Function)
addSrcFunc = func(fn *ssa.Function) {
res = append(res, fn)
for _, anon := range fn.AnonFuncs {
addSrcFunc(anon)
}
}
for _, pkg := range pkgs {
for _, file := range pkg.Syntax {
for _, decl := range file.Decls {
if decl, ok := decl.(*ast.FuncDecl); ok {
obj := pkg.TypesInfo.Defs[decl.Name].(*types.Func)
if obj == nil {
panic("nil *Func")
}
addSrcFunc(prog.FuncValue(obj))
}
}
}
}
return res
}