Use Delve v0.12.1 instead of master

vendor/github.com/derekparker/delve/proc/mem.go

@@ -0,0 +1,57 @@
+package proc
+
+const cacheEnabled = true
+
+type memoryReadWriter interface {
+	readMemory(addr uintptr, size int) (data []byte, err error)
+	writeMemory(addr uintptr, data []byte) (written int, err error)
+}
+
+type memCache struct {
+	cacheAddr uintptr
+	cache     []byte
+	mem       memoryReadWriter
+}
+
+func (m *memCache) contains(addr uintptr, size int) bool {
+	return addr >= m.cacheAddr && addr <= (m.cacheAddr+uintptr(len(m.cache)-size))
+}
+
+func (m *memCache) readMemory(addr uintptr, size int) (data []byte, err error) {
+	if m.contains(addr, size) {
+		d := make([]byte, size)
+		copy(d, m.cache[addr-m.cacheAddr:])
+		return d, nil
+	}
+
+	return m.mem.readMemory(addr, size)
+}
+
+func (m *memCache) writeMemory(addr uintptr, data []byte) (written int, err error) {
+	return m.mem.writeMemory(addr, data)
+}
+
+func cacheMemory(mem memoryReadWriter, addr uintptr, size int) memoryReadWriter {
+	if !cacheEnabled {
+		return mem
+	}
+	if size <= 0 {
+		return mem
+	}
+	if cacheMem, isCache := mem.(*memCache); isCache {
+		if cacheMem.contains(addr, size) {
+			return mem
+		} else {
+			cache, err := cacheMem.mem.readMemory(addr, size)
+			if err != nil {
+				return mem
+			}
+			return &memCache{addr, cache, mem}
+		}
+	}
+	cache, err := mem.readMemory(addr, size)
+	if err != nil {
+		return mem
+	}
+	return &memCache{addr, cache, mem}
+}