mirror of
https://github.com/golang/go
synced 2024-10-01 13:18:33 -06:00
fc4c97d1f1
Details: - builder is now un-exported and is now a per-package entity. - Package.nTo1Vars is now part of builder, where it belongs. - CREATE phase code split out into its own file, create.go - Context type is gone; it had become trivial after the Importer refactoring. - importer.PackageInfo.Imports() now encapsulates iteration over imports. Typical usage is now: prog := ssa.NewProgram(imp.Fset, mode) prog.CreatePackages(imp) prog.BuildAll() Builder.BuildPackage(Package) is now Package.Build() Builder.BuildAllPackages() is now Program.BuildAll() R=iant, gri CC=golang-dev https://golang.org/cl/9970044
109 lines
3.1 KiB
Go
109 lines
3.1 KiB
Go
package ssa_test
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import (
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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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"fmt"
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"go/ast"
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"go/parser"
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"os"
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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.Context{Loader: importer.MakeGoBuildLoader(nil)})
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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.Printf(err.Error()) // 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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info, err := imp.CreateSourcePackage("main", []*ast.File{file})
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if err != nil {
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fmt.Printf(err.Error()) // type error
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return
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}
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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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prog.CreatePackages(imp)
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mainPkg := prog.Package(info.Pkg)
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// Print out the package.
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mainPkg.DumpTo(os.Stdout)
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fmt.Println()
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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.Init.DumpTo(os.Stdout)
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for _, mem := range mainPkg.Members {
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if fn, ok := mem.(*ssa.Function); ok {
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fn.DumpTo(os.Stdout)
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}
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}
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// Output:
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//
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// package main:
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// var init$guard *bool
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// func main func()
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// const message message = "Hello, World!":untyped string
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//
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// # Name: main.init
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// # Synthetic
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// func init():
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// .0.entry: P:0 S:2
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// t0 = *init$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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// # Declared at hello.go:8:6
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// func main():
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// .0.entry: P:0 S:0
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// a0 = new [1]interface{} *[1]interface{}
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// t0 = &a0[0:untyped integer] *interface{}
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// t1 = make interface interface{} <- string ("Hello, World!":string) interface{}
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// *t0 = t1
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// t2 = slice a0[:] []interface{}
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// t3 = fmt.Println(t2) (n int, err error)
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// ret
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}
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