// interfaceMethod returns a function and receiver pointer for the specified
// interface and method pair.
func (fr *frame) interfaceMethod(lliface llvm.Value, ifacety types.Type, method *types.Func) (fn, recv *govalue) {
llitab := fr.builder.CreateExtractValue(lliface, 0, "")
recv = newValue(fr.builder.CreateExtractValue(lliface, 1, ""), types.Typ[types.UnsafePointer])
methodset := fr.types.MethodSet(ifacety)
// TODO(axw) cache ordered method index
index := -1
for i, m := range orderedMethodSet(methodset) {
if m.Obj() == method {
index = i
break
}
}
if index == -1 {
panic("could not find method index")
}
llitab = fr.builder.CreateBitCast(llitab, llvm.PointerType(llvm.PointerType(llvm.Int8Type(), 0), 0), "")
// Skip runtime type pointer.
llifnptr := fr.builder.CreateGEP(llitab, []llvm.Value{
llvm.ConstInt(llvm.Int32Type(), uint64(index+1), false),
}, "")
llifn := fr.builder.CreateLoad(llifnptr, "")
// Replace receiver type with unsafe.Pointer.
recvparam := types.NewParam(0, nil, "", types.Typ[types.UnsafePointer])
sig := method.Type().(*types.Signature)
sig = types.NewSignature(nil, recvparam, sig.Params(), sig.Results(), sig.Variadic())
fn = newValue(llifn, sig)
return
}
// ResultList = Type | ParamList .
func (p *parser) parseResultList(pkg *types.Package) *types.Tuple {
switch p.tok {
case '<':
return types.NewTuple(types.NewParam(token.NoPos, pkg, "", p.parseType(pkg)))
case '(':
params, _ := p.parseParamList(pkg)
return params
default:
return nil
}
}
// Param = Name ["..."] Type .
func (p *parser) parseParam(pkg *types.Package) (param *types.Var, isVariadic bool) {
name := p.parseName()
if p.tok == '.' {
p.next()
p.expect('.')
p.expect('.')
isVariadic = true
}
typ := p.parseType(pkg)
if isVariadic {
typ = types.NewSlice(typ)
}
param = types.NewParam(token.NoPos, pkg, name, typ)
return
}
// newVar creates a 'var' for use in a types.Tuple.
func newVar(name string, typ types.Type) *types.Var {
return types.NewParam(token.NoPos, nil, name, typ)
}