func (p *exporter) signature(sig *types.Signature) {
// We need the receiver information (T vs *T)
// for methods associated with named types.
// We do not record interface receiver types in the
// export data because 1) the importer can derive them
// from the interface type and 2) they create cycles
// in the type graph.
if recv := sig.Recv(); recv != nil {
if _, ok := recv.Type().Underlying().(*types.Interface); !ok {
// 1-element tuple
p.int(1)
p.param(recv)
} else {
// 0-element tuple
p.int(0)
}
} else {
// 0-element tuple
p.int(0)
}
p.tuple(sig.Params())
p.tuple(sig.Results())
if sig.Variadic() {
p.int(1)
} else {
p.int(0)
}
}
func (d *DIBuilder) descriptorSignature(t *types.Signature, name string) llvm.Metadata {
// If there's a receiver change the receiver to an
// additional (first) parameter, and take the value of
// the resulting signature instead.
if recv := t.Recv(); recv != nil {
params := t.Params()
paramvars := make([]*types.Var, int(params.Len()+1))
paramvars[0] = recv
for i := 0; i < int(params.Len()); i++ {
paramvars[i+1] = params.At(i)
}
params = types.NewTuple(paramvars...)
t := types.NewSignature(nil, nil, params, t.Results(), t.Variadic())
return d.typeDebugDescriptor(t, name)
}
if dt, ok := d.types.At(t).(llvm.Metadata); ok {
return dt
}
var returnType llvm.Metadata
results := t.Results()
switch n := results.Len(); n {
case 0:
returnType = d.DIType(nil) // void
case 1:
returnType = d.DIType(results.At(0).Type())
default:
fields := make([]*types.Var, results.Len())
for i := range fields {
f := results.At(i)
// Structs may not have multiple fields
// with the same name, excepting "_".
if f.Name() == "" {
f = types.NewVar(f.Pos(), f.Pkg(), "_", f.Type())
}
fields[i] = f
}
returnType = d.typeDebugDescriptor(types.NewStruct(fields, nil), "")
}
var paramTypes []llvm.Metadata
params := t.Params()
if params != nil && params.Len() > 0 {
paramTypes = make([]llvm.Metadata, params.Len()+1)
paramTypes[0] = returnType
for i := range paramTypes[1:] {
paramTypes[i+1] = d.DIType(params.At(i).Type())
}
} else {
paramTypes = []llvm.Metadata{returnType}
}
// TODO(axw) get position of type definition for File field
return d.builder.CreateSubroutineType(llvm.DISubroutineType{
Parameters: paramTypes,
})
}
func changeRecv(s *types.Signature, recv *types.Var) *types.Signature {
return types.NewSignature(nil, recv, s.Params(), s.Results(), s.Variadic())
}