diff --git a/vendor/go.uber.org/zap/stacktrace.go b/vendor/go.uber.org/zap/stacktrace.go
new file mode 100644
index 0000000..100fac2
--- /dev/null
+++ b/vendor/go.uber.org/zap/stacktrace.go
@@ -0,0 +1,126 @@
+// Copyright (c) 2016 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package zap
+
+import (
+	"runtime"
+	"strings"
+	"sync"
+
+	"go.uber.org/zap/internal/bufferpool"
+)
+
+const _zapPackage = "go.uber.org/zap"
+
+var (
+	_stacktracePool = sync.Pool{
+		New: func() interface{} {
+			return newProgramCounters(64)
+		},
+	}
+
+	// We add "." and "/" suffixes to the package name to ensure we only match
+	// the exact package and not any package with the same prefix.
+	_zapStacktracePrefixes       = addPrefix(_zapPackage, ".", "/")
+	_zapStacktraceVendorContains = addPrefix("/vendor/", _zapStacktracePrefixes...)
+)
+
+func takeStacktrace() string {
+	buffer := bufferpool.Get()
+	defer buffer.Free()
+	programCounters := _stacktracePool.Get().(*programCounters)
+	defer _stacktracePool.Put(programCounters)
+
+	var numFrames int
+	for {
+		// Skip the call to runtime.Counters and takeStacktrace so that the
+		// program counters start at the caller of takeStacktrace.
+		numFrames = runtime.Callers(2, programCounters.pcs)
+		if numFrames < len(programCounters.pcs) {
+			break
+		}
+		// Don't put the too-short counter slice back into the pool; this lets
+		// the pool adjust if we consistently take deep stacktraces.
+		programCounters = newProgramCounters(len(programCounters.pcs) * 2)
+	}
+
+	i := 0
+	skipZapFrames := true // skip all consecutive zap frames at the beginning.
+	frames := runtime.CallersFrames(programCounters.pcs[:numFrames])
+
+	// Note: On the last iteration, frames.Next() returns false, with a valid
+	// frame, but we ignore this frame. The last frame is a a runtime frame which
+	// adds noise, since it's only either runtime.main or runtime.goexit.
+	for frame, more := frames.Next(); more; frame, more = frames.Next() {
+		if skipZapFrames && isZapFrame(frame.Function) {
+			continue
+		} else {
+			skipZapFrames = false
+		}
+
+		if i != 0 {
+			buffer.AppendByte('\n')
+		}
+		i++
+		buffer.AppendString(frame.Function)
+		buffer.AppendByte('\n')
+		buffer.AppendByte('\t')
+		buffer.AppendString(frame.File)
+		buffer.AppendByte(':')
+		buffer.AppendInt(int64(frame.Line))
+	}
+
+	return buffer.String()
+}
+
+func isZapFrame(function string) bool {
+	for _, prefix := range _zapStacktracePrefixes {
+		if strings.HasPrefix(function, prefix) {
+			return true
+		}
+	}
+
+	// We can't use a prefix match here since the location of the vendor
+	// directory affects the prefix. Instead we do a contains match.
+	for _, contains := range _zapStacktraceVendorContains {
+		if strings.Contains(function, contains) {
+			return true
+		}
+	}
+
+	return false
+}
+
+type programCounters struct {
+	pcs []uintptr
+}
+
+func newProgramCounters(size int) *programCounters {
+	return &programCounters{make([]uintptr, size)}
+}
+
+func addPrefix(prefix string, ss ...string) []string {
+	withPrefix := make([]string, len(ss))
+	for i, s := range ss {
+		withPrefix[i] = prefix + s
+	}
+	return withPrefix
+}