mirror of
https://github.com/golang/go
synced 2024-10-01 10:38:33 -06:00
3f2f9a7e70
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
109 lines
3.2 KiB
Go
109 lines
3.2 KiB
Go
// Copyright 2013 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package ssa_test
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import (
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"fmt"
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"go/build"
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"go/parser"
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"os"
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"code.google.com/p/go.tools/importer"
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"code.google.com/p/go.tools/ssa"
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)
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// This program demonstrates how to run the SSA builder on a "Hello,
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// World!" program and shows the printed representation of packages,
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// functions and instructions.
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//
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// Within the function listing, the name of each BasicBlock such as
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// ".0.entry" is printed left-aligned, followed by the block's
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// Instructions.
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//
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// For each instruction that defines an SSA virtual register
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// (i.e. implements Value), the type of that value is shown in the
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// right column.
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//
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// Build and run the ssadump.go program in this package if you want a
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// standalone tool with similar functionality.
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//
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func Example() {
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const hello = `
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package main
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import "fmt"
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const message = "Hello, World!"
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func main() {
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fmt.Println(message)
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}
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`
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// Construct an importer. Imports will be loaded as if by 'go build'.
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imp := importer.New(&importer.Config{Build: &build.Default})
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// Parse the input file.
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file, err := parser.ParseFile(imp.Fset, "hello.go", hello, parser.DeclarationErrors)
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if err != nil {
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fmt.Print(err) // parse error
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return
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}
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// Create a "main" package containing one file.
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mainInfo := imp.LoadMainPackage(file)
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// Create SSA-form program representation.
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var mode ssa.BuilderMode
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prog := ssa.NewProgram(imp.Fset, mode)
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if err := prog.CreatePackages(imp); err != nil {
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fmt.Print(err) // type error in some package
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return
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}
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mainPkg := prog.Package(mainInfo.Pkg)
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// Print out the package.
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mainPkg.DumpTo(os.Stdout)
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// Build SSA code for bodies of functions in mainPkg.
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mainPkg.Build()
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// Print out the package-level functions.
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mainPkg.Func("init").DumpTo(os.Stdout)
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mainPkg.Func("main").DumpTo(os.Stdout)
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// Output:
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//
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// package main:
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// func init func()
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// var init$guard *bool
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// func main func()
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// const message message = "Hello, World!":untyped string
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//
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// # Name: main.init
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// # Synthetic: package initializer
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// func init():
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// .0.entry: P:0 S:2
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// t0 = *init$guard bool
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// if t0 goto 2.init.done else 1.init.start
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// .1.init.start: P:1 S:1
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// *init$guard = true:bool
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// t1 = fmt.init() ()
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// jump 2.init.done
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// .2.init.done: P:2 S:0
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// ret
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//
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// # Name: main.main
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// # Location: hello.go:8:6
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// func main():
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// .0.entry: P:0 S:0
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// t0 = new [1]interface{} (varargs) *[1]interface{}
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// t1 = &t0[0:untyped integer] *interface{}
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// t2 = make interface{} <- string ("Hello, World!":string) interface{}
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// *t1 = t2
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// t3 = slice t0[:] []interface{}
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// t4 = fmt.Println(t3) (n int, err error)
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// ret
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}
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