// Analyze performs Rapid Type Analysis, starting at the specified root
// functions. It returns nil if no roots were specified.
//
// If buildCallGraph is true, Result.CallGraph will contain a call
// graph; otherwise, only the other fields (reachable functions) are
// populated.
//
func Analyze(roots []*ssa.Function, buildCallGraph bool) *Result {
if len(roots) == 0 {
return nil
}
r := &rta{
result: &Result{Reachable: make(map[*ssa.Function]struct{ AddrTaken bool })},
prog: roots[0].Prog,
}
if buildCallGraph {
// TODO(adonovan): change callgraph API to eliminate the
// notion of a distinguished root node. Some callgraphs
// have many roots, or none.
r.result.CallGraph = callgraph.New(roots[0])
}
hasher := typeutil.MakeHasher()
r.result.RuntimeTypes.SetHasher(hasher)
r.addrTakenFuncsBySig.SetHasher(hasher)
r.dynCallSites.SetHasher(hasher)
r.invokeSites.SetHasher(hasher)
r.concreteTypes.SetHasher(hasher)
r.interfaceTypes.SetHasher(hasher)
// Visit functions, processing their instructions, and adding
// new functions to the worklist, until a fixed point is
// reached.
var shadow []*ssa.Function // for efficiency, we double-buffer the worklist
r.worklist = append(r.worklist, roots...)
for len(r.worklist) > 0 {
shadow, r.worklist = r.worklist, shadow[:0]
for _, f := range shadow {
r.visitFunc(f)
}
}
return r.result
}
// Create returns a new SSA Program. An SSA Package is created for
// each transitively error-free package of iprog.
//
// Code for bodies of functions is not built until Build() is called
// on the result.
//
// mode controls diagnostics and checking during SSA construction.
//
func Create(iprog *loader.Program, mode BuilderMode) *Program {
prog := &Program{
Fset: iprog.Fset,
imported: make(map[string]*Package),
packages: make(map[*types.Package]*Package),
thunks: make(map[selectionKey]*Function),
bounds: make(map[*types.Func]*Function),
mode: mode,
}
h := typeutil.MakeHasher() // protected by methodsMu, in effect
prog.methodSets.SetHasher(h)
prog.canon.SetHasher(h)
for _, info := range iprog.AllPackages {
// TODO(adonovan): relax this constraint if the
// program contains only "soft" errors.
if info.TransitivelyErrorFree {
prog.CreatePackage(info)
}
}
return prog
}
// Hash functions and equivalence relation:
// hashString computes the FNV hash of s.
func hashString(s string) int {
var h uint32
for i := 0; i < len(s); i++ {
h ^= uint32(s[i])
h *= 16777619
}
return int(h)
}
var (
mu sync.Mutex
hasher = typeutil.MakeHasher()
)
// hashType returns a hash for t such that
// types.Identical(x, y) => hashType(x) == hashType(y).
func hashType(t types.Type) int {
mu.Lock()
h := int(hasher.Hash(t))
mu.Unlock()
return h
}
// usesBuiltinMap returns true if the built-in hash function and
// equivalence relation for type t are consistent with those of the
// interpreter's representation of type t. Such types are: all basic
// types (bool, numbers, string), pointers and channels.
// Analyze runs the pointer analysis with the scope and options
// specified by config, and returns the (synthetic) root of the callgraph.
//
// Pointer analysis of a transitively closed well-typed program should
// always succeed. An error can occur only due to an internal bug.
//
func Analyze(config *Config) (result *Result, err error) {
if config.Mains == nil {
return nil, fmt.Errorf("no main/test packages to analyze (check $GOROOT/$GOPATH)")
}
defer func() {
if p := recover(); p != nil {
err = fmt.Errorf("internal error in pointer analysis: %v (please report this bug)", p)
fmt.Fprintln(os.Stderr, "Internal panic in pointer analysis:")
debug.PrintStack()
}
}()
a := &analysis{
config: config,
log: config.Log,
prog: config.prog(),
globalval: make(map[ssa.Value]nodeid),
globalobj: make(map[ssa.Value]nodeid),
flattenMemo: make(map[types.Type][]*fieldInfo),
trackTypes: make(map[types.Type]bool),
atFuncs: make(map[*ssa.Function]bool),
hasher: typeutil.MakeHasher(),
intrinsics: make(map[*ssa.Function]intrinsic),
result: &Result{
Queries: make(map[ssa.Value]Pointer),
IndirectQueries: make(map[ssa.Value]Pointer),
},
deltaSpace: make([]int, 0, 100),
}
if false {
a.log = os.Stderr // for debugging crashes; extremely verbose
}
if a.log != nil {
fmt.Fprintln(a.log, "==== Starting analysis")
}
// Pointer analysis requires a complete program for soundness.
// Check to prevent accidental misconfiguration.
for _, pkg := range a.prog.AllPackages() {
// (This only checks that the package scope is complete,
// not that func bodies exist, but it's a good signal.)
if !pkg.Object.Complete() {
return nil, fmt.Errorf(`pointer analysis requires a complete program yet package %q was incomplete (don't set loader.Config.ImportFromBinary during loading)`, pkg.Object.Path())
}
}
if reflect := a.prog.ImportedPackage("reflect"); reflect != nil {
rV := reflect.Object.Scope().Lookup("Value")
a.reflectValueObj = rV
a.reflectValueCall = a.prog.LookupMethod(rV.Type(), nil, "Call")
a.reflectType = reflect.Object.Scope().Lookup("Type").Type().(*types.Named)
a.reflectRtypeObj = reflect.Object.Scope().Lookup("rtype")
a.reflectRtypePtr = types.NewPointer(a.reflectRtypeObj.Type())
// Override flattening of reflect.Value, treating it like a basic type.
tReflectValue := a.reflectValueObj.Type()
a.flattenMemo[tReflectValue] = []*fieldInfo{{typ: tReflectValue}}
// Override shouldTrack of reflect.Value and *reflect.rtype.
// Always track pointers of these types.
a.trackTypes[tReflectValue] = true
a.trackTypes[a.reflectRtypePtr] = true
a.rtypes.SetHasher(a.hasher)
a.reflectZeros.SetHasher(a.hasher)
}
if runtime := a.prog.ImportedPackage("runtime"); runtime != nil {
a.runtimeSetFinalizer = runtime.Func("SetFinalizer")
}
a.computeTrackBits()
a.generate()
a.showCounts()
if optRenumber {
a.renumber()
}
N := len(a.nodes) // excludes solver-created nodes
if optHVN {
if debugHVNCrossCheck {
// Cross-check: run the solver once without
// optimization, once with, and compare the
// solutions.
savedConstraints := a.constraints
a.solve()
a.dumpSolution("A.pts", N)
// Restore.
a.constraints = savedConstraints
for _, n := range a.nodes {
n.solve = new(solverState)
}
a.nodes = a.nodes[:N]
// rtypes is effectively part of the solver state.
a.rtypes = typeutil.Map{}
a.rtypes.SetHasher(a.hasher)
}
a.hvn()
}
if debugHVNCrossCheck {
runtime.GC()
runtime.GC()
}
a.solve()
// Compare solutions.
if optHVN && debugHVNCrossCheck {
a.dumpSolution("B.pts", N)
if !diff("A.pts", "B.pts") {
return nil, fmt.Errorf("internal error: optimization changed solution")
}
}
// Create callgraph.Nodes in deterministic order.
if cg := a.result.CallGraph; cg != nil {
for _, caller := range a.cgnodes {
cg.CreateNode(caller.fn)
}
}
// Add dynamic edges to call graph.
var space [100]int
for _, caller := range a.cgnodes {
for _, site := range caller.sites {
for _, callee := range a.nodes[site.targets].solve.pts.AppendTo(space[:0]) {
a.callEdge(caller, site, nodeid(callee))
}
}
}
return a.result, nil
}