1 files changed, 121 insertions, 0 deletions
diff --git a/src/runtime/traceback_test.go b/src/runtime/traceback_test.go
new file mode 100644
index 0000000000..2a0497e9a9
--- /dev/null
+++ b/src/runtime/traceback_test.go
@@ -0,0 +1,121 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package runtime_test
+
+import (
+	"bytes"
+	"runtime"
+	"testing"
+)
+
+var testTracebackArgsBuf [1000]byte
+
+func TestTracebackArgs(t *testing.T) {
+	tests := []struct {
+		fn     func() int
+		expect string
+	}{
+		// simple ints
+		{
+			func() int { return testTracebackArgs1(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12) },
+			"testTracebackArgs1(0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa, ...)",
+		},
+		// some aggregates
+		{
+			func() int {
+				return testTracebackArgs2(false, struct {
+					a, b, c int
+					x       [2]int
+				}{1, 2, 3, [2]int{4, 5}}, [0]int{}, [3]byte{6, 7, 8})
+			},
+			"testTracebackArgs2(0x0, {0x1, 0x2, 0x3, {0x4, 0x5}}, {}, {0x6, 0x7, 0x8})",
+		},
+		{
+			func() int { return testTracebackArgs3([3]byte{1, 2, 3}, 4, 5, 6, [3]byte{7, 8, 9}) },
+			"testTracebackArgs3({0x1, 0x2, 0x3}, 0x4, 0x5, 0x6, {0x7, 0x8, 0x9})",
+		},
+		// too deeply nested type
+		{
+			func() int { return testTracebackArgs4(false, [1][1][1][1][1][1][1][1][1][1]int{}) },
+			"testTracebackArgs4(0x0, {{{{{...}}}}})",
+		},
+		// a lot of zero-sized type
+		{
+			func() int {
+				z := [0]int{}
+				return testTracebackArgs5(false, struct {
+					x int
+					y [0]int
+					z [2][0]int
+				}{1, z, [2][0]int{}}, z, z, z, z, z, z, z, z, z, z, z, z)
+			},
+			"testTracebackArgs5(0x0, {0x1, {}, {{}, {}}}, {}, {}, {}, {}, {}, ...)",
+		},
+	}
+	for _, test := range tests {
+		n := test.fn()
+		got := testTracebackArgsBuf[:n]
+		if !bytes.Contains(got, []byte(test.expect)) {
+			t.Errorf("traceback does not contain expected string: want %q, got\n%s", test.expect, got)
+		}
+	}
+}
+
+//go:noinline
+func testTracebackArgs1(a, b, c, d, e, f, g, h, i, j, k, l int) int {
+	n := runtime.Stack(testTracebackArgsBuf[:], false)
+	if a < 0 {
+		// use in-reg args to keep them alive
+		return a + b + c + d + e + f + g + h + i + j + k + l
+	}
+	return n
+}
+
+//go:noinline
+func testTracebackArgs2(a bool, b struct {
+	a, b, c int
+	x       [2]int
+}, _ [0]int, d [3]byte) int {
+	n := runtime.Stack(testTracebackArgsBuf[:], false)
+	if a {
+		// use in-reg args to keep them alive
+		return b.a + b.b + b.c + b.x[0] + b.x[1] + int(d[0]) + int(d[1]) + int(d[2])
+	}
+	return n
+
+}
+
+//go:noinline
+//go:registerparams
+func testTracebackArgs3(x [3]byte, a, b, c int, y [3]byte) int {
+	n := runtime.Stack(testTracebackArgsBuf[:], false)
+	if a < 0 {
+		// use in-reg args to keep them alive
+		return int(x[0]) + int(x[1]) + int(x[2]) + a + b + c + int(y[0]) + int(y[1]) + int(y[2])
+	}
+	return n
+}
+
+//go:noinline
+func testTracebackArgs4(a bool, x [1][1][1][1][1][1][1][1][1][1]int) int {
+	n := runtime.Stack(testTracebackArgsBuf[:], false)
+	if a {
+		panic(x) // use args to keep them alive
+	}
+	return n
+}
+
+//go:noinline
+func testTracebackArgs5(a bool, x struct {
+	x int
+	y [0]int
+	z [2][0]int
+}, _, _, _, _, _, _, _, _, _, _, _, _ [0]int) int {
+	n := runtime.Stack(testTracebackArgsBuf[:], false)
+	if a {
+		panic(x) // use args to keep them alive
+	}
+	return n
+}