// valueOffsetNode ascertains the node for tuple/struct value v,
// then returns the node for its subfield #index.
//
func (a *analysis) valueOffsetNode(v ssa.Value, index int) nodeid {
id := a.valueNode(v)
if id == 0 {
panic(fmt.Sprintf("cannot offset within n0: %s = %s", v.Name(), v))
}
return id + nodeid(a.offsetOf(v.Type(), index))
}
func (f *Function) Ident(v ssa.Value) *identifier {
if ident, ok := f.identifiers[v.Name()]; ok {
if ident == nil {
ice("nil ident")
}
return ident
}
switch v := v.(type) {
case *ssa.Const:
ident := identifier{f: f, name: v.Name(), typ: v.Type(), local: nil, param: nil, cnst: v}
ident.initStorage(true)
f.identifiers[v.Name()] = &ident
return &ident
}
local, err := f.newIdent(v)
if err != nil {
return nil
}
f.identifiers[v.Name()] = &local
return &local
}
func (fr *frame) value(v ssa.Value) (result *govalue) {
switch v := v.(type) {
case nil:
return nil
case *ssa.Function:
return fr.resolveFunctionDescriptor(v)
case *ssa.Const:
return fr.newValueFromConst(v.Value, v.Type())
case *ssa.Global:
if g, ok := fr.globals[v]; ok {
return newValue(g, v.Type())
}
// Create an external global. Globals for this package are defined
// on entry to translatePackage, and have initialisers.
llelemtyp := fr.llvmtypes.ToLLVM(deref(v.Type()))
vname := fr.types.mc.mangleGlobalName(v)
llglobal := llvm.AddGlobal(fr.module.Module, llelemtyp, vname)
llglobal = llvm.ConstBitCast(llglobal, fr.llvmtypes.ToLLVM(v.Type()))
fr.globals[v] = llglobal
return newValue(llglobal, v.Type())
}
if value, ok := fr.env[v]; ok {
return value
}
panic("Instruction not visited yet")
}
func (l langType) set1usePtr(v ssa.Value, oup oneUsePtr) string {
if l.hc.useRegisterArray {
l.hc.map1usePtr[v] = oneUsePtr{obj: oup.obj, off: oup.off}
return ""
}
nam := v.Name()
newObj := ""
newOff := ""
ret := ""
madeVarObj := false
madeVarOff := false
for _, eoup := range l.hc.map1usePtr { // TODO speed this up with another map or two
if oup.obj == eoup.objOrig && eoup.varObj {
newObj = eoup.obj
}
if oup.off == eoup.offOrig && eoup.varOff {
newOff = eoup.off
}
}
if newObj == "" {
ret += "var " + nam + "obj=" + oup.obj + ";\n"
newObj = nam + "obj"
madeVarObj = true
l.hc.tempVarList = append(l.hc.tempVarList, regToFree{nam + "obj", "Dynamic"})
}
if newOff == "" {
ret += "var " + nam + "off=" + oup.off + ";\n"
newOff = nam + "off"
madeVarOff = true
}
l.hc.map1usePtr[v] = oneUsePtr{newObj, newOff, oup.obj, oup.off, madeVarObj, madeVarOff}
return ret
}
// AddQuery adds v to Config.IndirectQueries.
// Precondition: CanPoint(v.Type().Underlying().(*types.Pointer).Elem()).
func (c *Config) AddIndirectQuery(v ssa.Value) {
if c.IndirectQueries == nil {
c.IndirectQueries = make(map[ssa.Value]struct{})
}
if !CanPoint(mustDeref(v.Type())) {
panic(fmt.Sprintf("%s is not the address of a pointer-like value: %s", v, v.Type()))
}
c.IndirectQueries[v] = struct{}{}
}
// AddQuery adds v to Config.Queries.
// Precondition: CanPoint(v.Type()).
// TODO(adonovan): consider returning a new Pointer for this query,
// which will be initialized during analysis. That avoids the needs
// for the corresponding ssa.Value-keyed maps in Config and Result.
func (c *Config) AddQuery(v ssa.Value) {
if !CanPoint(v.Type()) {
panic(fmt.Sprintf("%s is not a pointer-like value: %s", v, v.Type()))
}
if c.Queries == nil {
c.Queries = make(map[ssa.Value]struct{})
}
c.Queries[v] = struct{}{}
}
// genOffsetAddr generates constraints for a 'v=ptr.field' (FieldAddr)
// or 'v=ptr[*]' (IndexAddr) instruction v.
func (a *analysis) genOffsetAddr(cgn *cgnode, v ssa.Value, ptr nodeid, offset uint32) {
dst := a.valueNode(v)
if obj := a.objectNode(cgn, v); obj != 0 {
// Pre-apply offsetAddrConstraint.solve().
a.addressOf(v.Type(), dst, obj)
} else {
a.offsetAddr(v.Type(), dst, ptr, offset)
}
}
// prepareCallFn prepares a caller Function to visit performing necessary context switching and returns a new callee Function.
// rcvr is non-nil if invoke call
func (caller *Function) prepareCallFn(common *ssa.CallCommon, fn *ssa.Function, rcvr ssa.Value) *Function {
callee := NewFunction(caller)
callee.Fn = fn
// This function was called before
if _, ok := callee.Prog.FuncInstance[callee.Fn]; ok {
callee.Prog.FuncInstance[callee.Fn]++
} else {
callee.Prog.FuncInstance[callee.Fn] = 0
}
callee.FuncDef.Name = fn.String()
callee.id = callee.Prog.FuncInstance[callee.Fn]
for i, param := range callee.Fn.Params {
var argCaller ssa.Value
if rcvr != nil {
if i == 0 {
argCaller = rcvr
} else {
argCaller = common.Args[i-1]
}
} else {
argCaller = common.Args[i]
}
if _, ok := argCaller.Type().(*types.Chan); ok {
callee.FuncDef.AddParams(&migo.Parameter{Caller: argCaller, Callee: param})
}
if inst, ok := caller.locals[argCaller]; ok {
callee.locals[param] = inst
callee.revlookup[argCaller.Name()] = param.Name()
// Copy array and struct from parent.
if elems, ok := caller.arrays[inst]; ok {
callee.arrays[inst] = elems
}
if fields, ok := caller.structs[inst]; ok {
callee.structs[inst] = fields
}
if maps, ok := caller.maps[inst]; ok {
callee.maps[inst] = maps
}
} else if c, ok := argCaller.(*ssa.Const); ok {
callee.locals[param] = &Const{c}
}
}
if inst, ok := caller.locals[common.Value]; ok {
if cap, ok := caller.Prog.closures[inst]; ok {
for i, fv := range callee.Fn.FreeVars {
callee.locals[fv] = cap[i]
if _, ok := derefType(fv.Type()).(*types.Chan); ok {
callee.FuncDef.AddParams(&migo.Parameter{Caller: fv, Callee: fv})
}
}
}
}
return callee
}
// purgeChanOps removes channels that are of different type as queryOp, i.e.
// channel we are looking for.
func purgeChanOps(ops []ChanOp, ch ssa.Value) []ChanOp {
i := 0
for _, op := range ops {
if types.Identical(op.Value.Type().Underlying().(*types.Chan).Elem(), ch.Type().Underlying().(*types.Chan).Elem()) {
ops[i] = op
i++
}
}
ops = ops[:i]
return ops
}
func (f *Function) sizeof(val ssa.Value) uint {
if _, ok := val.(*ssa.Const); ok {
return f.sizeofConst(val.(*ssa.Const))
}
info, ok := f.identifiers[val.Name()]
if !ok {
ice(fmt.Sprintf("unknown name (%v), value (%v)\n", val.Name(), val))
}
_, _, size := info.Addr()
return size
}
func (f *Function) LoadValue(loc ssa.Instruction, val ssa.Value, offset uint, size uint) (string, *register, *Error) {
ident := f.Ident(val)
asm := fmt.Sprintf("// BEGIN LoadValue, val %v (= %v), offset %v, size %v\n", val.Name(), val, offset, size)
a, reg, err := f.LoadIdent(loc, ident, offset, size)
if err != nil {
return "", nil, err
}
asm += a
asm += fmt.Sprintf("// END LoadValue, val %v (= %v), offset %v, size %v\n", val.Name(), val, offset, size)
return asm, reg, nil
}
func reg(reg ssa.Value) string {
if reg == nil {
return "???.nil"
}
if reg.Parent() != nil {
return fmt.Sprintf("%s.\033[4m%s\033[0m", reg.Parent().String(), reg.Name())
}
return fmt.Sprintf("???.\033[4m%s\033[0m", reg.Name())
}
func (f *Function) isAlive(loc ssa.Instruction, val ssa.Value) bool {
block := loc.Block()
instrIdx := f.instrIdxInBlock(loc)
if val.Referrers() == nil {
return false
}
for _, ref := range *val.Referrers() {
bk := ref.Block()
if bk.Index != block.Index {
continue
}
for i, _ := range bk.Instrs {
if i > instrIdx {
return true
}
}
}
return false
}
func (fr *frame) get(key ssa.Value) value {
switch key := key.(type) {
case nil:
// Hack; simplifies handling of optional attributes
// such as ssa.Slice.{Low,High}.
return nil
case *ssa.Function, *ssa.Builtin:
return key
case *ssa.Const:
return constValue(key)
case *ssa.Global:
if r, ok := fr.i.globals[key]; ok {
return r
}
}
if r, ok := fr.env[key]; ok {
return r
}
panic(fmt.Sprintf("get: no value for %T: %v", key, key.Name()))
}
// runPTA runs the pointer analysis of the selected SSA value or address.
func runPTA(o *Oracle, v ssa.Value, isAddr bool) (ptrs []pointerResult, err error) {
buildSSA(o)
T := v.Type()
if isAddr {
o.ptaConfig.AddIndirectQuery(v)
T = deref(T)
} else {
o.ptaConfig.AddQuery(v)
}
ptares := ptrAnalysis(o)
var ptr pointer.Pointer
if isAddr {
ptr = ptares.IndirectQueries[v]
} else {
ptr = ptares.Queries[v]
}
if ptr == (pointer.Pointer{}) {
return nil, fmt.Errorf("pointer analysis did not find expression (dead code?)")
}
pts := ptr.PointsTo()
if pointer.CanHaveDynamicTypes(T) {
// Show concrete types for interface/reflect.Value expression.
if concs := pts.DynamicTypes(); concs.Len() > 0 {
concs.Iterate(func(conc types.Type, pta interface{}) {
labels := pta.(pointer.PointsToSet).Labels()
sort.Sort(byPosAndString(labels)) // to ensure determinism
ptrs = append(ptrs, pointerResult{conc, labels})
})
}
} else {
// Show labels for other expressions.
labels := pts.Labels()
sort.Sort(byPosAndString(labels)) // to ensure determinism
ptrs = append(ptrs, pointerResult{T, labels})
}
sort.Sort(byTypeString(ptrs)) // to ensure determinism
return ptrs, nil
}
func (f *Function) newIdent(v ssa.Value) (identifier, *Error) {
name := v.Name()
typ := v.Type()
size := sizeof(typ)
offset := int(size)
if align(typ) > size {
offset = int(align(typ))
}
ident := identifier{
f: f,
name: name,
typ: typ,
param: nil,
local: nil,
value: v,
offset: -int(f.localIdentsSize()) - offset}
ident.initStorage(false)
f.identifiers[name] = &ident
// zeroing the memory is done at the beginning of the function
return ident, nil
}
func (f *Function) SliceLen(loc ssa.Instruction, slice ssa.Value, ident *identifier) (string, *Error) {
if _, ok := slice.Type().(*types.Slice); !ok {
panic(ice(fmt.Sprintf("getting len of slice, type should slice not (%v)", slice.Type().String())))
}
asm := fmt.Sprintf("// BEGIN SliceLen: slice (%v), ident (%v)\n", slice, ident.String())
a, reg, err := f.LoadValue(loc, slice, sliceLenOffset(), sliceLenSize())
asm += a
if err != nil {
return asm, err
}
a, err = f.StoreValue(loc, ident, reg)
asm += a
if err != nil {
return asm, err
}
f.freeReg(reg)
asm += fmt.Sprintf("// END SliceLen: slice (%v), ident (%v)\n", slice, *ident)
return asm, nil
}
// setValueNode associates node id with the value v.
// cgn identifies the context iff v is a local variable.
//
func (a *analysis) setValueNode(v ssa.Value, id nodeid, cgn *cgnode) {
if cgn != nil {
a.localval[v] = id
} else {
a.globalval[v] = id
}
if a.log != nil {
fmt.Fprintf(a.log, "\tval[%s] = n%d (%T)\n", v.Name(), id, v)
}
// Due to context-sensitivity, we may encounter the same Value
// in many contexts. We merge them to a canonical node, since
// that's what all clients want.
// Record the (v, id) relation if the client has queried pts(v).
if _, ok := a.config.Queries[v]; ok {
t := v.Type()
ptr, ok := a.result.Queries[v]
if !ok {
// First time? Create the canonical query node.
ptr = Pointer{a, a.addNodes(t, "query")}
a.result.Queries[v] = ptr
}
a.result.Queries[v] = ptr
a.copy(ptr.n, id, a.sizeof(t))
}
// Record the (*v, id) relation if the client has queried pts(*v).
if _, ok := a.config.IndirectQueries[v]; ok {
t := v.Type()
ptr, ok := a.result.IndirectQueries[v]
if !ok {
// First time? Create the canonical indirect query node.
ptr = Pointer{a, a.addNodes(v.Type(), "query.indirect")}
a.result.IndirectQueries[v] = ptr
}
a.genLoad(cgn, ptr.n, v, 0, a.sizeof(t))
}
}
// valueNode returns the id of the value node for v, creating it (and
// the association) as needed. It may return zero for uninteresting
// values containing no pointers.
//
func (a *analysis) valueNode(v ssa.Value) nodeid {
// Value nodes for locals are created en masse by genFunc.
if id, ok := a.localval[v]; ok {
return id
}
// Value nodes for globals are created on demand.
id, ok := a.globalval[v]
if !ok {
var comment string
if a.log != nil {
comment = v.String()
}
id = a.addNodes(v.Type(), comment)
if obj := a.objectNode(nil, v); obj != 0 {
a.addressOf(v.Type(), id, obj)
}
a.setValueNode(v, id, nil)
}
return id
}
// Declare creates an llvm.dbg.declare call for the specified function
// parameter or local variable.
func (d *DIBuilder) Declare(b llvm.Builder, v ssa.Value, llv llvm.Value, paramIndex int) {
tag := tagAutoVariable
if paramIndex >= 0 {
tag = tagArgVariable
}
var diFile llvm.Value
var line int
if file := d.fset.File(v.Pos()); file != nil {
line = file.Line(v.Pos())
diFile = d.getFile(file)
}
localVar := d.builder.CreateLocalVariable(d.scope(), llvm.DILocalVariable{
Tag: tag,
Name: llv.Name(),
File: diFile,
Line: line,
ArgNo: paramIndex + 1,
Type: d.DIType(v.Type()),
})
expr := d.builder.CreateExpression(nil)
d.builder.InsertDeclareAtEnd(llv, localVar, expr, b.GetInsertBlock())
}
func escapes(val ssa.Value, bb *ssa.BasicBlock, pending []ssa.Value) bool {
for _, p := range pending {
if val == p {
return false
}
}
for _, ref := range *val.Referrers() {
switch ref := ref.(type) {
case *ssa.Phi:
// We must consider the variable to have escaped if it is
// possible for the program to see more than one "version"
// of the variable at once, as this requires the program
// to use heap allocation for the multiple versions.
//
// I (pcc) think that this is only possible (without stores)
// in the case where a phi node that (directly or indirectly)
// refers to the allocation dominates the allocation.
if ref.Block().Dominates(bb) {
return true
}
if escapes(ref, bb, append(pending, val)) {
return true
}
case *ssa.BinOp, *ssa.ChangeType, *ssa.Convert, *ssa.ChangeInterface, *ssa.MakeInterface, *ssa.Slice, *ssa.FieldAddr, *ssa.IndexAddr, *ssa.TypeAssert, *ssa.Extract:
if escapes(ref.(ssa.Value), bb, append(pending, val)) {
return true
}
case *ssa.Range, *ssa.DebugRef:
continue
case *ssa.UnOp:
if ref.Op == token.MUL || ref.Op == token.ARROW {
continue
}
if escapes(ref, bb, append(pending, val)) {
return true
}
case *ssa.Store:
if val == ref.Val {
return true
}
case *ssa.Call:
if builtin, ok := ref.Call.Value.(*ssa.Builtin); ok {
switch builtin.Name() {
case "cap", "len", "copy", "ssa:wrapnilchk":
continue
case "append":
if ref.Call.Args[0] == val && escapes(ref, bb, append(pending, val)) {
return true
}
default:
return true
}
} else {
return true
}
default:
return true
}
}
return false
}
// objectNode returns the object to which v points, if known.
// In other words, if the points-to set of v is a singleton, it
// returns the sole label, zero otherwise.
//
// We exploit this information to make the generated constraints less
// dynamic. For example, a complex load constraint can be replaced by
// a simple copy constraint when the sole destination is known a priori.
//
// Some SSA instructions always have singletons points-to sets:
// Alloc, Function, Global, MakeChan, MakeClosure, MakeInterface, MakeMap, MakeSlice.
// Others may be singletons depending on their operands:
// FreeVar, Const, Convert, FieldAddr, IndexAddr, Slice.
//
// Idempotent. Objects are created as needed, possibly via recursion
// down the SSA value graph, e.g IndexAddr(FieldAddr(Alloc))).
//
func (a *analysis) objectNode(cgn *cgnode, v ssa.Value) nodeid {
switch v.(type) {
case *ssa.Global, *ssa.Function, *ssa.Const, *ssa.FreeVar:
// Global object.
obj, ok := a.globalobj[v]
if !ok {
switch v := v.(type) {
case *ssa.Global:
obj = a.nextNode()
a.addNodes(mustDeref(v.Type()), "global")
a.endObject(obj, nil, v)
case *ssa.Function:
obj = a.makeFunctionObject(v, nil)
case *ssa.Const:
// not addressable
case *ssa.FreeVar:
// not addressable
}
if a.log != nil {
fmt.Fprintf(a.log, "\tglobalobj[%s] = n%d\n", v, obj)
}
a.globalobj[v] = obj
}
return obj
}
// Local object.
obj, ok := a.localobj[v]
if !ok {
switch v := v.(type) {
case *ssa.Alloc:
obj = a.nextNode()
a.addNodes(mustDeref(v.Type()), "alloc")
a.endObject(obj, cgn, v)
case *ssa.MakeSlice:
obj = a.nextNode()
a.addNodes(sliceToArray(v.Type()), "makeslice")
a.endObject(obj, cgn, v)
case *ssa.MakeChan:
obj = a.nextNode()
a.addNodes(v.Type().Underlying().(*types.Chan).Elem(), "makechan")
a.endObject(obj, cgn, v)
case *ssa.MakeMap:
obj = a.nextNode()
tmap := v.Type().Underlying().(*types.Map)
a.addNodes(tmap.Key(), "makemap.key")
elem := a.addNodes(tmap.Elem(), "makemap.value")
// To update the value field, MapUpdate
// generates store-with-offset constraints which
// the presolver can't model, so we must mark
// those nodes indirect.
for id, end := elem, elem+nodeid(a.sizeof(tmap.Elem())); id < end; id++ {
a.mapValues = append(a.mapValues, id)
}
a.endObject(obj, cgn, v)
case *ssa.MakeInterface:
tConc := v.X.Type()
obj = a.makeTagged(tConc, cgn, v)
// Copy the value into it, if nontrivial.
if x := a.valueNode(v.X); x != 0 {
a.copy(obj+1, x, a.sizeof(tConc))
}
case *ssa.FieldAddr:
if xobj := a.objectNode(cgn, v.X); xobj != 0 {
obj = xobj + nodeid(a.offsetOf(mustDeref(v.X.Type()), v.Field))
}
case *ssa.IndexAddr:
if xobj := a.objectNode(cgn, v.X); xobj != 0 {
obj = xobj + 1
}
case *ssa.Slice:
obj = a.objectNode(cgn, v.X)
case *ssa.Convert:
// TODO(adonovan): opt: handle these cases too:
// - unsafe.Pointer->*T conversion acts like Alloc
// - string->[]byte/[]rune conversion acts like MakeSlice
}
if a.log != nil {
fmt.Fprintf(a.log, "\tlocalobj[%s] = n%d\n", v.Name(), obj)
}
a.localobj[v] = obj
}
return obj
}
func (f *Function) StoreValAddr(loc ssa.Instruction, val ssa.Value, addr *identifier) (string, *Error) {
if ident := f.Ident(val); ident == nil {
ice("error in allocating local")
}
if addr.isConst() {
ice(fmt.Sprintf("invalid addr \"%v\"", addr))
}
asm := ""
asm += fmt.Sprintf("// BEGIN StoreValAddr addr name:%v, val name:%v\n", addr.name, val.Name()) + asm
if isComplex(val.Type()) {
return ErrorMsg("complex32/64 unsupported")
} else if isXmm(val.Type()) {
a, valReg, err := f.LoadValue(loc, val, 0, f.sizeof(val))
if err != nil {
return a, err
}
asm += a
a, err = f.StoreValue(loc, addr, valReg)
if err != nil {
return a, err
}
asm += a
f.freeReg(valReg)
} else {
size := f.sizeof(val)
iterations := size
datasize := 1
if size >= sizeBasic(types.Int64) {
iterations = size / sizeBasic(types.Int64)
datasize = 8
} else if size >= sizeBasic(types.Int32) {
iterations = size / sizeBasic(types.Int32)
datasize = 4
} else if size >= sizeBasic(types.Int16) {
iterations = size / sizeBasic(types.Int16)
datasize = 2
}
if size > sizeInt() {
if size%sizeInt() != 0 {
ice(fmt.Sprintf("Size (%v) not multiple of sizeInt (%v)", size, sizeInt()))
}
}
for i := 0; i < int(iterations); i++ {
offset := uint(i * datasize)
a, valReg, err := f.LoadValue(loc, val, offset, uint(datasize))
if err != nil {
return a, err
}
asm += a
a, err = f.AssignRegIdent(loc, valReg, addr, offset, uint(datasize))
if err != nil {
return a, err
}
asm += a
f.freeReg(valReg)
}
}
asm += fmt.Sprintf("// END StoreValAddr addr name:%v, val name:%v\n", addr.name, val.Name())
return asm, nil
}
// storeRetvals takes retval (SSA value from caller storing return value(s)) and
// stores the return value of function (callee).
func (caller *Function) storeRetvals(infer *TypeInfer, retval ssa.Value, callee *Function) {
if !callee.HasBody() {
switch callee.Fn.Signature.Results().Len() {
case 0:
// Nothing.
case 1:
// Creating external instance because return value may be used.
caller.locals[retval] = &External{caller.Fn, retval.Type().Underlying(), caller.InstanceID()}
infer.Logger.Print(caller.Sprintf(ExitSymbol + "external"))
default:
caller.locals[retval] = &External{caller.Fn, retval.Type().Underlying(), caller.InstanceID()}
caller.tuples[caller.locals[retval]] = make(Tuples, callee.Fn.Signature.Results().Len())
infer.Logger.Print(caller.Sprintf(ExitSymbol+"external len=%d", callee.Fn.Signature.Results().Len()))
}
return
}
switch len(callee.retvals) {
case 0:
// Nothing.
case 1:
// XXX Pick the last return value from the exit paths
// This assumes idiomatic Go for error path to return early
// https://golang.org/doc/effective_go.html#if
caller.locals[retval] = callee.retvals[len(callee.retvals)-1]
if a, ok := callee.arrays[caller.locals[retval]]; ok {
caller.arrays[caller.locals[retval]] = a
}
if s, ok := callee.structs[caller.locals[retval]]; ok {
caller.structs[caller.locals[retval]] = s
}
if m, ok := callee.maps[caller.locals[retval]]; ok {
caller.maps[caller.locals[retval]] = m
}
if a, ok := callee.Prog.arrays[caller.locals[retval]]; ok {
caller.arrays[caller.locals[retval]] = a
}
if s, ok := callee.Prog.structs[caller.locals[retval]]; ok {
caller.structs[caller.locals[retval]] = s
}
switch inst := caller.locals[retval].(type) {
case *Value:
infer.Logger.Print(caller.Sprintf(ExitSymbol+"[1] %s", inst))
return
case *External:
infer.Logger.Print(caller.Sprintf(ExitSymbol+"[1] (ext) %s", inst))
return
case *Const:
infer.Logger.Print(caller.Sprintf(ExitSymbol+"[1] constant %s", inst))
return
default:
infer.Logger.Fatalf("return[1]: %s: not an instance %+v", ErrUnknownValue, retval)
}
default:
caller.locals[retval] = &Value{retval, caller.InstanceID(), int64(0)}
if callee.Fn.Signature.Results().Len() == 1 {
caller.locals[retval] = callee.retvals[len(callee.retvals)-1]
if a, ok := callee.arrays[caller.locals[retval]]; ok {
caller.arrays[caller.locals[retval]] = a
}
if s, ok := callee.structs[caller.locals[retval]]; ok {
caller.structs[caller.locals[retval]] = s
}
if m, ok := callee.maps[caller.locals[retval]]; ok {
caller.maps[caller.locals[retval]] = m
}
if a, ok := callee.Prog.arrays[caller.locals[retval]]; ok {
caller.arrays[caller.locals[retval]] = a
}
if s, ok := callee.Prog.structs[caller.locals[retval]]; ok {
caller.structs[caller.locals[retval]] = s
}
} else {
caller.tuples[caller.locals[retval]] = make(Tuples, callee.Fn.Signature.Results().Len())
for i := range callee.retvals {
tupleIdx := i % callee.Fn.Signature.Results().Len()
if callee.retvals[i] != nil {
caller.tuples[caller.locals[retval]][tupleIdx] = callee.retvals[i]
}
if a, ok := callee.arrays[callee.retvals[i]]; ok {
caller.arrays[callee.retvals[i]] = a
}
if s, ok := callee.structs[callee.retvals[i]]; ok {
caller.structs[callee.retvals[i]] = s
}
if m, ok := callee.maps[callee.retvals[i]]; ok {
caller.maps[callee.retvals[i]] = m
}
if a, ok := callee.Prog.arrays[callee.retvals[i]]; ok {
caller.arrays[callee.retvals[i]] = a
}
if s, ok := callee.Prog.structs[callee.retvals[i]]; ok {
caller.structs[callee.retvals[i]] = s
}
}
}
// XXX Pick the return values from the last exit path
// This assumes idiomatic Go for error path to return early
// https://golang.org/doc/effective_go.html#if
infer.Logger.Print(caller.Sprintf(ExitSymbol+"[%d/%d] %v", callee.Fn.Signature.Results().Len(), len(callee.retvals), caller.tuples[caller.locals[retval]]))
}
}
// isCondFair returns true if an if condition (bool expression) is constant.
func (fa *FairnessAnalysis) isCondFair(cond ssa.Value) bool {
switch cond := cond.(type) {
case *ssa.Const:
fa.logger.Println(color.YellowString("Warning: loop condition is constant"))
return false
case *ssa.BinOp: // <, <=, !=, ==
if _, xConst := cond.X.(*ssa.Const); xConst {
if _, yConst := cond.Y.(*ssa.Const); yConst {
fa.logger.Println(color.YellowString("Warning: loop condition is constant"))
return false
} else {
fa.logger.Println(color.YellowString("Try to trace back on Y"))
}
} else {
fa.logger.Println(color.YellowString("Try to trace back on X"))
}
case *ssa.UnOp:
if _, con := cond.X.(*ssa.Const); con {
fa.logger.Println(color.YellowString("Warning: loop condition is constant"))
return false
}
case *ssa.Call:
fa.logger.Println(color.YellowString("Warning:%s: condition is function call --> unsure", fa.info.FSet.Position(cond.Pos()).String()))
return false
}
return true // Assume fair by default
}