// 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.Pkg.Path() + "." + 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. sizes is the
// effective type-sizing function for this program.
//
// Interpret returns the exit code of the program: 2 for panic (like
// gc does), or the argument to os.Exit for normal termination.
//
// The SSA program must include the "runtime" package.
//
func Interpret(mainpkg *ssa.Package, mode Mode, sizes types.Sizes, filename string, args []string) (exitCode int) {
i := &interpreter{
prog: mainpkg.Prog,
globals: make(map[ssa.Value]*value),
mode: mode,
sizes: sizes,
}
runtimePkg := i.prog.ImportedPackage("runtime")
if runtimePkg == nil {
panic("ssa.Program doesn't include runtime package")
}
i.runtimeErrorString = runtimePkg.Type("errorString").Object().Type()
initReflect(i)
i.osArgs = append(i.osArgs, filename)
for _, arg := range args {
i.osArgs = append(i.osArgs, arg)
}
for _, pkg := range i.prog.AllPackages() {
// Initialize global storage.
for _, m := range pkg.Members {
switch v := m.(type) {
case *ssa.Global:
cell := zero(deref(v.Type()))
i.globals[v] = &cell
}
}
// Ad-hoc initialization for magic system variables.
switch pkg.Pkg.Path() {
case "syscall":
setGlobal(i, pkg, "envs", environ)
case "reflect":
deleteBodies(pkg, "DeepEqual", "deepValueEqual")
case "runtime":
sz := sizes.Sizeof(pkg.Pkg.Scope().Lookup("MemStats").Type())
setGlobal(i, pkg, "sizeof_C_MStats", uintptr(sz))
deleteBodies(pkg, "GOROOT", "gogetenv")
}
}
// 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: %v\n", p, 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.Func("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
}