// callSSA interprets a call to function fn with arguments args,
// and lexical environment env, returning its result.
// callpos is the position of the callsite.
//
func callSSA(i *interpreter, caller *frame, callpos token.Pos, fn *ssa.Function, args []value, env []value) value {
if i.mode&EnableTracing != 0 {
fset := fn.Prog.Fset
// TODO(adonovan): fix: loc() lies for external functions.
fmt.Fprintf(os.Stderr, "Entering %s%s.\n", fn, loc(fset, fn.Pos()))
suffix := ""
if caller != nil {
suffix = ", resuming " + caller.fn.String() + loc(fset, callpos)
}
defer fmt.Fprintf(os.Stderr, "Leaving %s%s.\n", fn, suffix)
}
if fn.Enclosing == nil {
name := fn.String()
if ext := externals[name]; ext != nil {
if i.mode&EnableTracing != 0 {
fmt.Fprintln(os.Stderr, "\t(external)")
}
return ext(fn, args)
}
if fn.Blocks == nil {
panic("no code for function: " + name)
}
}
fr := &frame{
i: i,
caller: caller, // currently unused; for unwinding.
fn: fn,
env: make(map[ssa.Value]value),
block: fn.Blocks[0],
locals: make([]value, len(fn.Locals)),
}
for i, l := range fn.Locals {
fr.locals[i] = zero(deref(l.Type()))
fr.env[l] = &fr.locals[i]
}
for i, p := range fn.Params {
fr.env[p] = args[i]
}
for i, fv := range fn.FreeVars {
fr.env[fv] = env[i]
}
for fr.block != nil {
runFrame(fr)
}
// Destroy the locals to avoid accidental use after return.
for i := range fn.Locals {
fr.locals[i] = bad{}
}
return fr.result
}
// callSSA interprets a call to function fn with arguments args,
// and lexical environment env, returning its result.
// callpos is the position of the callsite.
//
func callSSA(i *interpreter, caller *frame, callpos token.Pos, fn *ssa.Function, args []value, env []value) value {
if i.mode&EnableTracing != 0 {
fset := fn.Prog.Files
// TODO(adonovan): fix: loc() lies for external functions.
fmt.Fprintf(os.Stderr, "Entering %s%s.\n", fn.FullName(), loc(fset, fn.Pos()))
suffix := ""
if caller != nil {
suffix = ", resuming " + caller.fn.FullName() + loc(fset, callpos)
}
defer fmt.Fprintf(os.Stderr, "Leaving %s%s.\n", fn.FullName(), suffix)
}
if fn.Enclosing == nil {
name := fn.FullName()
if ext := externals[name]; ext != nil {
if i.mode&EnableTracing != 0 {
fmt.Fprintln(os.Stderr, "\t(external)")
}
return ext(fn, args)
}
if fn.Blocks == nil {
panic("no code for function: " + name)
}
}
fr := &frame{
i: i,
caller: caller, // currently unused; for unwinding.
fn: fn,
env: make(map[ssa.Value]value),
block: fn.Blocks[0],
locals: make([]value, len(fn.Locals)),
}
for i, l := range fn.Locals {
fr.locals[i] = zero(l.Type().Deref())
fr.env[l] = &fr.locals[i]
}
for i, p := range fn.Params {
fr.env[p] = args[i]
}
for i, fv := range fn.FreeVars {
fr.env[fv] = env[i]
}
var instr ssa.Instruction
defer func() {
if fr.status != stComplete {
if fr.i.mode&DisableRecover != 0 {
return // let interpreter crash
}
fr.status, fr.panic = stPanic, recover()
}
fr.rundefers()
// Destroy the locals to avoid accidental use after return.
for i := range fn.Locals {
fr.locals[i] = bad{}
}
if fr.status == stPanic {
panic(fr.panic) // panic stack is not entirely clean
}
}()
for {
if i.mode&EnableTracing != 0 {
fmt.Fprintf(os.Stderr, ".%s:\n", fr.block)
}
block:
for _, instr = range fr.block.Instrs {
if i.mode&EnableTracing != 0 {
if v, ok := instr.(ssa.Value); ok {
fmt.Fprintln(os.Stderr, "\t", v.Name(), "=", instr)
} else {
fmt.Fprintln(os.Stderr, "\t", instr)
}
}
switch visitInstr(fr, instr) {
case kReturn:
fr.status = stComplete
return fr.result
case kNext:
// no-op
case kJump:
break block
}
}
}
panic("unreachable")
}