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go/ssa/visit.go
Alan Donovan 3f2f9a7e70 go.tools/importer: generalize command-line syntax.
Motivation: pointer analysis tools (like the oracle) want the
user to specify a set of initial packages, like 'go test'.
This change enables the user to specify a set of packages on
the command line using importer.LoadInitialPackages(args).

Each argument is interpreted as either:
- a comma-separated list of *.go source files together
  comprising one non-importable ad-hoc package.
  e.g. "src/pkg/net/http/triv.go" gives us [main].
- an import path, denoting both the imported package
  and its non-importable external test package, if any.
  e.g. "fmt" gives us [fmt, fmt_test].

Current type-checker limitations mean that only the first
import path may contribute tests: multiple packages augmented
by *_test.go files could create import cycles, which 'go test'
avoids by building a separate executable for each one.
That approach is less attractive for static analysis.

Details:  (many files touched, but importer.go is the crux)

importer:
- PackageInfo.Importable boolean indicates whether
  package is importable.
- un-expose Importer.Packages; expose AllPackages() instead.
- CreatePackageFromArgs has become LoadInitialPackages.
- imports() moved to util.go, renamed importsOf().
- InitialPackagesUsage usage message exported to clients.
- the package name for ad-hoc packages now comes from the
  'package' decl, not "main".

ssa.Program:
- added CreatePackages() method
- PackagesByPath un-exposed, renamed 'imported'.
- expose AllPackages and ImportedPackage accessors.

oracle:
- describe: explain and workaround a go/types bug.

Misc:
- Removed various unnecessary error.Error() calls in Printf args.

R=crawshaw
CC=golang-dev
https://golang.org/cl/13579043
2013-09-06 18:13:57 -04:00

78 lines
1.8 KiB
Go

// 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.
package ssa
// This file defines utilities for visiting the SSA representation of
// a Program.
//
// TODO(adonovan): improve the API:
// - permit client to supply a callback for each function,
// instruction, type with methods, etc?
// - return graph information about the traversal?
// - test coverage.
import "code.google.com/p/go.tools/go/types"
// AllFunctions returns the set of all functions (including anonymous
// functions and synthetic wrappers) in program prog.
//
// Precondition: all packages are built.
//
func AllFunctions(prog *Program) map[*Function]bool {
visit := visitor{
prog: prog,
seen: make(map[*Function]bool),
}
visit.program()
return visit.seen
}
type visitor struct {
prog *Program
seen map[*Function]bool
}
func (visit *visitor) program() {
for _, pkg := range visit.prog.AllPackages() {
for _, mem := range pkg.Members {
switch mem := mem.(type) {
case *Function:
visit.function(mem)
case *Type:
visit.methodSet(mem.Type())
visit.methodSet(types.NewPointer(mem.Type()))
}
}
}
}
func (visit *visitor) methodSet(typ types.Type) {
mset := typ.MethodSet()
for i, n := 0, mset.Len(); i < n; i++ {
// Side-effect: creates all wrapper methods.
visit.function(visit.prog.Method(mset.At(i)))
}
}
func (visit *visitor) function(fn *Function) {
if !visit.seen[fn] {
visit.seen[fn] = true
for _, b := range fn.Blocks {
for _, instr := range b.Instrs {
switch instr := instr.(type) {
case *MakeInterface:
visit.methodSet(instr.X.Type())
}
var buf [10]*Value // avoid alloc in common case
for _, op := range instr.Operands(buf[:0]) {
if fn, ok := (*op).(*Function); ok {
visit.function(fn)
}
}
}
}
}
}