// prepareCall determines the function value and argument values for a
// function call in a Call, Go or Defer instruction, peforming
// interface method lookup if needed.
//
func prepareCall(fr *frame, call *ssa.CallCommon) (fn value, args []value) {
if call.Func != nil {
// Function call.
fn = fr.get(call.Func)
} else {
// Interface method invocation.
recv := fr.get(call.Recv).(iface)
if recv.t == nil {
panic("method invoked on nil interface")
}
id := call.MethodId()
m := findMethodSet(fr.i, recv.t)[id]
if m == nil {
// Unreachable in well-typed programs.
panic(fmt.Sprintf("method set for dynamic type %v does not contain %s", recv.t, id))
}
_, aptr := recv.v.(*value) // actual pointerness
_, fptr := m.Signature.Recv().Type().(*types.Pointer) // formal pointerness
switch {
case aptr == fptr:
args = append(args, copyVal(recv.v))
case aptr:
// Calling func(T) with a *T receiver: make a copy.
args = append(args, copyVal(*recv.v.(*value)))
case fptr:
panic("illegal call of *T method with T receiver")
}
fn = m
}
for _, arg := range call.Args {
args = append(args, fr.get(arg))
}
return
}
// genInvoke generates constraints for a dynamic method invocation.
func (a *analysis) genInvoke(caller *cgnode, site *callsite, call *ssa.CallCommon, result nodeid) {
if call.Value.Type() == a.reflectType {
a.genInvokeReflectType(caller, site, call, result)
return
}
sig := call.Signature()
// Allocate a contiguous targets/params/results block for this call.
block := a.nextNode()
// pts(targets) will be the set of possible call targets
site.targets = a.addOneNode(sig, "invoke.targets", nil)
p := a.addNodes(sig.Params(), "invoke.params")
r := a.addNodes(sig.Results(), "invoke.results")
// Copy the actual parameters into the call's params block.
for i, n := 0, sig.Params().Len(); i < n; i++ {
sz := a.sizeof(sig.Params().At(i).Type())
a.copy(p, a.valueNode(call.Args[i]), sz)
p += nodeid(sz)
}
// Copy the call's results block to the actual results.
if result != 0 {
a.copy(result, r, a.sizeof(sig.Results()))
}
// We add a dynamic invoke constraint that will add
// edges from the caller's P/R block to the callee's
// P/R block for each discovered call target.
a.addConstraint(&invokeConstraint{call.Method, a.valueNode(call.Value), block})
}
// genStaticCall generates constraints for a statically dispatched function call.
func (a *analysis) genStaticCall(caller *cgnode, site *callsite, call *ssa.CallCommon, result nodeid) {
fn := call.StaticCallee()
// Special cases for inlined intrinsics.
switch fn {
case a.runtimeSetFinalizer:
// Inline SetFinalizer so the call appears direct.
site.targets = a.addOneNode(tInvalid, "SetFinalizer.targets", nil)
a.addConstraint(&runtimeSetFinalizerConstraint{
targets: site.targets,
x: a.valueNode(call.Args[0]),
f: a.valueNode(call.Args[1]),
})
return
case a.reflectValueCall:
// Inline (reflect.Value).Call so the call appears direct.
dotdotdot := false
ret := reflectCallImpl(a, caller, site, a.valueNode(call.Args[0]), a.valueNode(call.Args[1]), dotdotdot)
if result != 0 {
a.addressOf(result, ret)
}
return
}
// Ascertain the context (contour/cgnode) for a particular call.
var obj nodeid
if a.shouldUseContext(fn) {
obj = a.makeFunctionObject(fn, site) // new contour
} else {
obj = a.objectNode(nil, fn) // shared contour
}
a.callEdge(site, obj)
sig := call.Signature()
// Copy receiver, if any.
params := a.funcParams(obj)
args := call.Args
if sig.Recv() != nil {
sz := a.sizeof(sig.Recv().Type())
a.copy(params, a.valueNode(args[0]), sz)
params += nodeid(sz)
args = args[1:]
}
// Copy actual parameters into formal params block.
// Must loop, since the actuals aren't contiguous.
for i, arg := range args {
sz := a.sizeof(sig.Params().At(i).Type())
a.copy(params, a.valueNode(arg), sz)
params += nodeid(sz)
}
// Copy formal results block to actual result.
if result != 0 {
a.copy(result, a.funcResults(obj), a.sizeof(sig.Results()))
}
}
// genDynamicCall generates constraints for a dynamic function call.
func (a *analysis) genDynamicCall(caller *cgnode, site *callsite, call *ssa.CallCommon, result nodeid) {
// pts(targets) will be the set of possible call targets.
site.targets = a.valueNode(call.Value)
// We add dynamic closure rules that store the arguments into,
// and load the results from, the P/R block of each function
// discovered in pts(targets).
sig := call.Signature()
var offset uint32 = 1 // P/R block starts at offset 1
for i, arg := range call.Args {
sz := a.sizeof(sig.Params().At(i).Type())
a.genStore(caller, call.Value, a.valueNode(arg), offset, sz)
offset += sz
}
if result != 0 {
a.genLoad(caller, result, call.Value, offset, a.sizeof(sig.Results()))
}
}
// genDynamicCall generates constraints for a dynamic function call.
// It returns a node whose pts() will be the set of possible call targets.
//
func (a *analysis) genDynamicCall(call *ssa.CallCommon, result nodeid) nodeid {
fn := a.valueNode(call.Value)
sig := call.Signature()
// We add dynamic closure rules that store the arguments into,
// and load the results from, the P/R block of each function
// discovered in pts(fn).
var offset uint32 = 1 // P/R block starts at offset 1
for i, arg := range call.Args {
sz := a.sizeof(sig.Params().At(i).Type())
a.storeOffset(fn, a.valueNode(arg), offset, sz)
offset += sz
}
if result != 0 {
a.loadOffset(result, fn, offset, a.sizeof(sig.Results()))
}
return fn
}
// genStaticCall generates constraints for a statically dispatched
// function call. It returns a node whose pts() will be the set of
// possible call targets (in this case, a singleton).
//
func (a *analysis) genStaticCall(call *ssa.CallCommon, result nodeid) nodeid {
// Ascertain the context (contour/CGNode) for a particular call.
var obj nodeid
fn := call.StaticCallee()
if a.shouldUseContext(fn) {
obj = a.makeFunctionObject(fn) // new contour for this call
} else {
a.valueNode(fn) // ensure shared contour was created
obj = a.funcObj[fn] // ordinary (shared) contour.
}
sig := call.Signature()
targets := a.addOneNode(sig, "call.targets", nil)
a.addressOf(targets, obj) // (a singleton)
// Copy receiver, if any.
params := a.funcParams(obj)
args := call.Args
if sig.Recv() != nil {
sz := a.sizeof(sig.Recv().Type())
a.copy(params, a.valueNode(args[0]), sz)
params += nodeid(sz)
args = args[1:]
}
// Copy actual parameters into formal params block.
// Must loop, since the actuals aren't contiguous.
for i, arg := range args {
sz := a.sizeof(sig.Params().At(i).Type())
a.copy(params, a.valueNode(arg), sz)
params += nodeid(sz)
}
// Copy formal results block to actual result.
if result != 0 {
a.copy(result, a.funcResults(obj), a.sizeof(sig.Results()))
}
return targets
}