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https://github.com/golang/go
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be28dbb86f
PLEASE NOTE: the APIs for both "importer" and "ssa" packages will continue to evolve and both need some polishing; the key thing is that this CL splits them. The go.types/importer package contains contains the Importer, which takes care of the mechanics of loading a set of packages and type-checking them. It exposes for each package a PackageInfo containing: - the package's ASTs (i.e. the input to the typechecker) - the types.Package object - the memoization of the typechecker callbacks for identifier resolution, constant folding and expression type inference. Method-set computation (and hence bridge-method creation) is now moved to after creation of all packages: since they are no longer created in topological order, we can't guarantee the needed delegate methods exist yet. ssa.Package no longer has public TypeOf, ObjectOf, ValueOf methods. The private counterparts are valid only during the build phase. Also: - added to go/types an informative error (not crash) for an importer() returning nil without error. - removed Package.Name(), barely needed. - changed Package.String() slightly. - flag what looks like a bug in makeBridgeMethod. Will follow up. R=golang-dev, gri CC=golang-dev https://golang.org/cl/9898043
107 lines
3.1 KiB
Go
107 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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// Construct an SSA builder.
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builder := ssa.NewBuilder(&ssa.Context{}, imp)
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mainPkg := builder.PackageFor(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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builder.BuildPackage(mainPkg)
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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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