// setGlobal sets the value of a system-initialized global variable.
func setGlobal(i *interpreter, pkg *ssa.Package, name string, v value) {
if g, ok := i.globals[pkg.Var(name)]; ok {
*g = v
return
}
panic("no global variable: " + pkg.Name() + "." + name)
}
// Interpret interprets the Go program whose main package is mainpkg.
// mode specifies various interpreter options. filename and args are
// the initial values of os.Args for the target program.
//
// Interpret returns the exit code of the program: 2 for panic (like
// gc does), or the argument to os.Exit for normal termination.
//
func Interpret(mainpkg *ssa.Package, mode Mode, filename string, args []string) (exitCode int) {
i := &interpreter{
prog: mainpkg.Prog,
globals: make(map[ssa.Value]*value),
mode: mode,
}
initReflect(i)
for importPath, pkg := range i.prog.Packages {
// Initialize global storage.
for _, m := range pkg.Members {
switch v := m.(type) {
case *ssa.Global:
cell := zero(indirectType(v.Type()))
i.globals[v] = &cell
}
}
// Ad-hoc initialization for magic system variables.
switch importPath {
case "syscall":
var envs []value
for _, s := range os.Environ() {
envs = append(envs, s)
}
envs = append(envs, "GOSSAINTERP=1")
setGlobal(i, pkg, "envs", envs)
case "runtime":
// TODO(gri): expose go/types.sizeof so we can
// avoid this fragile magic number;
// unsafe.Sizeof(memStats) won't work since gc
// and go/types have different sizeof
// functions.
setGlobal(i, pkg, "sizeof_C_MStats", uintptr(3696))
case "os":
Args := []value{filename}
for _, s := range args {
Args = append(Args, s)
}
setGlobal(i, pkg, "Args", Args)
}
}
// Top-level error handler.
exitCode = 2
defer func() {
if exitCode != 2 || i.mode&DisableRecover != 0 {
return
}
switch p := recover().(type) {
case exitPanic:
exitCode = int(p)
return
case targetPanic:
fmt.Fprintln(os.Stderr, "panic:", toString(p.v))
case runtime.Error:
fmt.Fprintln(os.Stderr, "panic:", p.Error())
case string:
fmt.Fprintln(os.Stderr, "panic:", p)
default:
fmt.Fprintf(os.Stderr, "panic: unexpected type: %T\n", p)
}
// TODO(adonovan): dump panicking interpreter goroutine?
// buf := make([]byte, 0x10000)
// runtime.Stack(buf, false)
// fmt.Fprintln(os.Stderr, string(buf))
// (Or dump panicking target goroutine?)
}()
// Run!
call(i, nil, token.NoPos, mainpkg.Init, nil)
if mainFn := mainpkg.Func("main"); mainFn != nil {
call(i, nil, token.NoPos, mainFn, nil)
exitCode = 0
} else {
fmt.Fprintln(os.Stderr, "No main function.")
exitCode = 1
}
return
}