func()

in internal/gocore/type.go [115:217]

• 73 lines of code
• 20 McCabe index (conditional complexity)

func (p *Process) runtimeType2Type(a core.Address) *Type {
	if t := p.runtimeMap[a]; t != nil {
		return t
	}

	// Read runtime._type.size
	r := region{p: p, a: a, typ: p.findType("runtime._type")}
	size := int64(r.Field("size").Uintptr())

	// Find module this type is in.
	var m *module
	for _, x := range p.modules {
		if x.types <= a && a < x.etypes {
			m = x
			break
		}
	}

	// Read information out of the runtime._type.
	var name string
	if m != nil {
		x := m.types.Add(int64(r.Field("str").Int32()))
		n := uint16(p.proc.ReadUint8(x.Add(1)))<<8 + uint16(p.proc.ReadUint8(x.Add(2)))
		b := make([]byte, n)
		p.proc.ReadAt(b, x.Add(3))
		name = string(b)
		if r.Field("tflag").Uint8()&uint8(p.rtConstants["tflagExtraStar"]) != 0 {
			name = name[1:]
		}
	} else {
		// A reflect-generated type.
		// TODO: The actual name is in the runtime.reflectOffs map.
		// Too hard to look things up in maps here, just allocate a placeholder for now.
		name = fmt.Sprintf("reflect.generatedType%x", a)
	}

	// Read ptr/nonptr bits
	ptrSize := p.proc.PtrSize()
	nptrs := int64(r.Field("ptrdata").Uintptr()) / ptrSize
	var ptrs []int64
	if r.Field("kind").Uint8()&uint8(p.rtConstants["kindGCProg"]) == 0 {
		gcdata := r.Field("gcdata").Address()
		for i := int64(0); i < nptrs; i++ {
			if p.proc.ReadUint8(gcdata.Add(i/8))>>uint(i%8)&1 != 0 {
				ptrs = append(ptrs, i*ptrSize)
			}
		}
	} else {
		// TODO: run GC program to get ptr indexes
	}

	// Find a Type that matches this type.
	// (The matched type will be one constructed from DWARF info.)
	// It must match name, size, and pointer bits.
	var candidates []*Type
	for _, t := range p.runtimeNameMap[name] {
		if size == t.Size && equal(ptrs, t.ptrs()) {
			candidates = append(candidates, t)
		}
	}
	var t *Type
	if len(candidates) > 0 {
		// If a runtime type matches more than one DWARF type,
		// pick one arbitrarily.
		// This looks mostly harmless. DWARF has some redundant entries.
		// For example, [32]uint8 appears twice.
		// TODO: investigate the reason for this duplication.
		t = candidates[0]
	} else {
		// There's no corresponding DWARF type.  Make our own.
		t = &Type{Name: name, Size: size, Kind: KindStruct}
		n := t.Size / ptrSize

		// Types to use for ptr/nonptr fields of runtime types which
		// have no corresponding DWARF type.
		ptr := p.findType("unsafe.Pointer")
		nonptr := p.findType("uintptr")
		if ptr == nil || nonptr == nil {
			panic("ptr / nonptr standins missing")
		}

		for i := int64(0); i < n; i++ {
			typ := nonptr
			if len(ptrs) > 0 && ptrs[0] == i*ptrSize {
				typ = ptr
				ptrs = ptrs[1:]
			}
			t.Fields = append(t.Fields, Field{
				Name: fmt.Sprintf("f%d", i),
				Off:  i * ptrSize,
				Type: typ,
			})

		}
		if t.Size%ptrSize != 0 {
			// TODO: tail of <ptrSize data.
		}
	}
	// Memoize.
	p.runtimeMap[a] = t

	return t
}