x/tools/...: fork and tag !1.5 all files that use go/types et al

This change will ensure that the tree continues to work with go1.4.1.

All files continue to depend on golang.org/x/tools/go/types, but in a
follow-up change, I will switch the primary files to depend on the
standard go/types package.  Another (smaller) set of files will be
forked and tagged, this time !1.6, due to API differences between the
two packages.

All tests pass using 1.4.1, 1.5, and ~1.6 (tip).

Change-Id: Ifd75a6330e120957d646be91693daaba1ce0e8c9
Reviewed-on: https://go-review.googlesource.com/18333
Reviewed-by: Robert Griesemer <gri@golang.org>

cmd/bundle/main.go

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build go1.5
+
 // The bundle command concatenates the source files of a package,
 // renaming package-level names by adding a prefix and renaming
 // identifiers as needed to preserve referential integrity.

cmd/ssadump/main.go

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build go1.5
+
 // ssadump: a tool for displaying and interpreting the SSA form of Go programs.
 package main // import "golang.org/x/tools/cmd/ssadump"
 

cmd/ssadump/main14.go

@@ -0,0 +1,188 @@
+// 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.
+
+// +build !go1.5
+
+// ssadump: a tool for displaying and interpreting the SSA form of Go programs.
+package main // import "golang.org/x/tools/cmd/ssadump"
+
+import (
+	"flag"
+	"fmt"
+	"go/build"
+	"os"
+	"runtime"
+	"runtime/pprof"
+
+	"golang.org/x/tools/go/buildutil"
+	"golang.org/x/tools/go/loader"
+	"golang.org/x/tools/go/ssa"
+	"golang.org/x/tools/go/ssa/interp"
+	"golang.org/x/tools/go/ssa/ssautil"
+	"golang.org/x/tools/go/types"
+)
+
+var (
+	modeFlag = ssa.BuilderModeFlag(flag.CommandLine, "build", 0)
+
+	testFlag = flag.Bool("test", false, "Loads test code (*_test.go) for imported packages.")
+
+	runFlag = flag.Bool("run", false, "Invokes the SSA interpreter on the program.")
+
+	interpFlag = flag.String("interp", "", `Options controlling the SSA test interpreter.
+The value is a sequence of zero or more more of these letters:
+R	disable [R]ecover() from panic; show interpreter crash instead.
+T	[T]race execution of the program.  Best for single-threaded programs!
+`)
+)
+
+const usage = `SSA builder and interpreter.
+Usage: ssadump [<flag> ...] <args> ...
+Use -help flag to display options.
+
+Examples:
+% ssadump -build=F hello.go              # dump SSA form of a single package
+% ssadump -run -interp=T hello.go        # interpret a program, with tracing
+% ssadump -run -test unicode -- -test.v  # interpret the unicode package's tests, verbosely
+` + loader.FromArgsUsage +
+	`
+When -run is specified, ssadump will run the program.
+The entry point depends on the -test flag:
+if clear, it runs the first package named main.
+if set, it runs the tests of each package.
+`
+
+var cpuprofile = flag.String("cpuprofile", "", "write cpu profile to file")
+
+func init() {
+	flag.Var((*buildutil.TagsFlag)(&build.Default.BuildTags), "tags", buildutil.TagsFlagDoc)
+
+	// If $GOMAXPROCS isn't set, use the full capacity of the machine.
+	// For small machines, use at least 4 threads.
+	if os.Getenv("GOMAXPROCS") == "" {
+		n := runtime.NumCPU()
+		if n < 4 {
+			n = 4
+		}
+		runtime.GOMAXPROCS(n)
+	}
+}
+
+func main() {
+	if err := doMain(); err != nil {
+		fmt.Fprintf(os.Stderr, "ssadump: %s\n", err)
+		os.Exit(1)
+	}
+}
+
+func doMain() error {
+	flag.Parse()
+	args := flag.Args()
+
+	conf := loader.Config{Build: &build.Default}
+
+	// Choose types.Sizes from conf.Build.
+	var wordSize int64 = 8
+	switch conf.Build.GOARCH {
+	case "386", "arm":
+		wordSize = 4
+	}
+	conf.TypeChecker.Sizes = &types.StdSizes{
+		MaxAlign: 8,
+		WordSize: wordSize,
+	}
+
+	var interpMode interp.Mode
+	for _, c := range *interpFlag {
+		switch c {
+		case 'T':
+			interpMode |= interp.EnableTracing
+		case 'R':
+			interpMode |= interp.DisableRecover
+		default:
+			return fmt.Errorf("unknown -interp option: '%c'", c)
+		}
+	}
+
+	if len(args) == 0 {
+		fmt.Fprint(os.Stderr, usage)
+		os.Exit(1)
+	}
+
+	// Profiling support.
+	if *cpuprofile != "" {
+		f, err := os.Create(*cpuprofile)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			os.Exit(1)
+		}
+		pprof.StartCPUProfile(f)
+		defer pprof.StopCPUProfile()
+	}
+
+	// Use the initial packages from the command line.
+	args, err := conf.FromArgs(args, *testFlag)
+	if err != nil {
+		return err
+	}
+
+	// The interpreter needs the runtime package.
+	if *runFlag {
+		conf.Import("runtime")
+	}
+
+	// Load, parse and type-check the whole program.
+	iprog, err := conf.Load()
+	if err != nil {
+		return err
+	}
+
+	// Create and build SSA-form program representation.
+	prog := ssautil.CreateProgram(iprog, *modeFlag)
+
+	// Build and display only the initial packages
+	// (and synthetic wrappers), unless -run is specified.
+	for _, info := range iprog.InitialPackages() {
+		prog.Package(info.Pkg).Build()
+	}
+
+	// Run the interpreter.
+	if *runFlag {
+		prog.Build()
+
+		var main *ssa.Package
+		pkgs := prog.AllPackages()
+		if *testFlag {
+			// If -test, run all packages' tests.
+			if len(pkgs) > 0 {
+				main = prog.CreateTestMainPackage(pkgs...)
+			}
+			if main == nil {
+				return fmt.Errorf("no tests")
+			}
+		} else {
+			// Otherwise, run main.main.
+			for _, pkg := range pkgs {
+				if pkg.Pkg.Name() == "main" {
+					main = pkg
+					if main.Func("main") == nil {
+						return fmt.Errorf("no func main() in main package")
+					}
+					break
+				}
+			}
+			if main == nil {
+				return fmt.Errorf("no main package")
+			}
+		}
+
+		if runtime.GOARCH != build.Default.GOARCH {
+			return fmt.Errorf("cross-interpretation is not supported (target has GOARCH %s, interpreter has %s)",
+				build.Default.GOARCH, runtime.GOARCH)
+		}
+
+		interp.Interpret(main, interpMode, conf.TypeChecker.Sizes, main.Pkg.Path(), args)
+	}
+	return nil
+}

go/callgraph/cha/cha.go

@@ -1,3 +1,9 @@
+// Copyright 2014 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.
+
+// +build go1.5
+
 // Package cha computes the call graph of a Go program using the Class
 // Hierarchy Analysis (CHA) algorithm.
 //

go/callgraph/cha/cha14.go

@@ -0,0 +1,126 @@
+// Copyright 2014 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.
+
+// +build !go1.5
+
+// Package cha computes the call graph of a Go program using the Class
+// Hierarchy Analysis (CHA) algorithm.
+//
+// CHA was first described in "Optimization of Object-Oriented Programs
+// Using Static Class Hierarchy Analysis", Jeffrey Dean, David Grove,
+// and Craig Chambers, ECOOP'95.
+//
+// CHA is related to RTA (see go/callgraph/rta); the difference is that
+// CHA conservatively computes the entire "implements" relation between
+// interfaces and concrete types ahead of time, whereas RTA uses dynamic
+// programming to construct it on the fly as it encounters new functions
+// reachable from main.  CHA may thus include spurious call edges for
+// types that haven't been instantiated yet, or types that are never
+// instantiated.
+//
+// Since CHA conservatively assumes that all functions are address-taken
+// and all concrete types are put into interfaces, it is sound to run on
+// partial programs, such as libraries without a main or test function.
+//
+package cha // import "golang.org/x/tools/go/callgraph/cha"
+
+import (
+	"golang.org/x/tools/go/callgraph"
+	"golang.org/x/tools/go/ssa"
+	"golang.org/x/tools/go/ssa/ssautil"
+	"golang.org/x/tools/go/types"
+	"golang.org/x/tools/go/types/typeutil"
+)
+
+// CallGraph computes the call graph of the specified program using the
+// Class Hierarchy Analysis algorithm.
+//
+func CallGraph(prog *ssa.Program) *callgraph.Graph {
+	cg := callgraph.New(nil) // TODO(adonovan) eliminate concept of rooted callgraph
+
+	allFuncs := ssautil.AllFunctions(prog)
+
+	// funcsBySig contains all functions, keyed by signature.  It is
+	// the effective set of address-taken functions used to resolve
+	// a dynamic call of a particular signature.
+	var funcsBySig typeutil.Map // value is []*ssa.Function
+
+	// methodsByName contains all methods,
+	// grouped by name for efficient lookup.
+	methodsByName := make(map[string][]*ssa.Function)
+
+	// methodsMemo records, for every abstract method call call I.f on
+	// interface type I, the set of concrete methods C.f of all
+	// types C that satisfy interface I.
+	methodsMemo := make(map[*types.Func][]*ssa.Function)
+	lookupMethods := func(m *types.Func) []*ssa.Function {
+		methods, ok := methodsMemo[m]
+		if !ok {
+			I := m.Type().(*types.Signature).Recv().Type().Underlying().(*types.Interface)
+			for _, f := range methodsByName[m.Name()] {
+				C := f.Signature.Recv().Type() // named or *named
+				if types.Implements(C, I) {
+					methods = append(methods, f)
+				}
+			}
+			methodsMemo[m] = methods
+		}
+		return methods
+	}
+
+	for f := range allFuncs {
+		if f.Signature.Recv() == nil {
+			// Package initializers can never be address-taken.
+			if f.Name() == "init" && f.Synthetic == "package initializer" {
+				continue
+			}
+			funcs, _ := funcsBySig.At(f.Signature).([]*ssa.Function)
+			funcs = append(funcs, f)
+			funcsBySig.Set(f.Signature, funcs)
+		} else {
+			methodsByName[f.Name()] = append(methodsByName[f.Name()], f)
+		}
+	}
+
+	addEdge := func(fnode *callgraph.Node, site ssa.CallInstruction, g *ssa.Function) {
+		gnode := cg.CreateNode(g)
+		callgraph.AddEdge(fnode, site, gnode)
+	}
+
+	addEdges := func(fnode *callgraph.Node, site ssa.CallInstruction, callees []*ssa.Function) {
+		// Because every call to a highly polymorphic and
+		// frequently used abstract method such as
+		// (io.Writer).Write is assumed to call every concrete
+		// Write method in the program, the call graph can
+		// contain a lot of duplication.
+		//
+		// TODO(adonovan): opt: consider factoring the callgraph
+		// API so that the Callers component of each edge is a
+		// slice of nodes, not a singleton.
+		for _, g := range callees {
+			addEdge(fnode, site, g)
+		}
+	}
+
+	for f := range allFuncs {
+		fnode := cg.CreateNode(f)
+		for _, b := range f.Blocks {
+			for _, instr := range b.Instrs {
+				if site, ok := instr.(ssa.CallInstruction); ok {
+					call := site.Common()
+					if call.IsInvoke() {
+						addEdges(fnode, site, lookupMethods(call.Method))
+					} else if g := call.StaticCallee(); g != nil {
+						addEdge(fnode, site, g)
+					} else if _, ok := call.Value.(*ssa.Builtin); !ok {
+						callees, _ := funcsBySig.At(call.Signature()).([]*ssa.Function)
+						addEdges(fnode, site, callees)
+					}
+				}
+			}
+		}
+	}
+
+	return cg
+}