src/runtime/traceback_test.go - go - Git at Google

 // 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"
 	"internal/goexperiment"
 	"internal/testenv"
 	"runtime"
 	"strings"
 	"testing"
 )

 var testTracebackArgsBuf [1000]byte

 func TestTracebackArgs(t *testing.T) {
 	if *flagQuick {
 		t.Skip("-quick")
 	}
 	optimized := !strings.HasSuffix(testenv.Builder(), "-noopt")
 	abiSel := func(x, y string) string {
 		// select expected output based on ABI
 		// In noopt build we always spill arguments so the output is the same as stack ABI.
 		if optimized && goexperiment.RegabiArgs {
 			return x
 		}
 		return y
 	}

 	tests := []struct {
 		fn     func() int
 		expect string
 	}{
 		// simple ints
 		{
 			func() int { return testTracebackArgs1(1, 2, 3, 4, 5) },
 			"testTracebackArgs1(0x1, 0x2, 0x3, 0x4, 0x5)",
 		},
 		// 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, {}, {{}, {}}}, {}, {}, {}, {}, {}, ...)",
 		},

 		// edge cases for ...
 		// no ... for 10 args
 		{
 			func() int { return testTracebackArgs6a(1, 2, 3, 4, 5, 6, 7, 8, 9, 10) },
 			"testTracebackArgs6a(0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa)",
 		},
 		// has ... for 11 args
 		{
 			func() int { return testTracebackArgs6b(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11) },
 			"testTracebackArgs6b(0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa, ...)",
 		},
 		// no ... for aggregates with 10 words
 		{
 			func() int { return testTracebackArgs7a([10]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}) },
 			"testTracebackArgs7a({0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa})",
 		},
 		// has ... for aggregates with 11 words
 		{
 			func() int { return testTracebackArgs7b([11]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}) },
 			"testTracebackArgs7b({0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa, ...})",
 		},
 		// no ... for aggregates, but with more args
 		{
 			func() int { return testTracebackArgs7c([10]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, 11) },
 			"testTracebackArgs7c({0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa}, ...)",
 		},
 		// has ... for aggregates and also for more args
 		{
 			func() int { return testTracebackArgs7d([11]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}, 12) },
 			"testTracebackArgs7d({0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa, ...}, ...)",
 		},
 		// nested aggregates, no ...
 		{
 			func() int { return testTracebackArgs8a(testArgsType8a{1, 2, 3, 4, 5, 6, 7, 8, [2]int{9, 10}}) },
 			"testTracebackArgs8a({0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, {0x9, 0xa}})",
 		},
 		// nested aggregates, ... in inner but not outer
 		{
 			func() int { return testTracebackArgs8b(testArgsType8b{1, 2, 3, 4, 5, 6, 7, 8, [3]int{9, 10, 11}}) },
 			"testTracebackArgs8b({0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, {0x9, 0xa, ...}})",
 		},
 		// nested aggregates, ... in outer but not inner
 		{
 			func() int { return testTracebackArgs8c(testArgsType8c{1, 2, 3, 4, 5, 6, 7, 8, [2]int{9, 10}, 11}) },
 			"testTracebackArgs8c({0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, {0x9, 0xa}, ...})",
 		},
 		// nested aggregates, ... in both inner and outer
 		{
 			func() int { return testTracebackArgs8d(testArgsType8d{1, 2, 3, 4, 5, 6, 7, 8, [3]int{9, 10, 11}, 12}) },
 			"testTracebackArgs8d({0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, {0x9, 0xa, ...}, ...})",
 		},

 		// Register argument liveness.
 		// 1, 3 are used and live, 2, 4 are dead (in register ABI).
 		// Address-taken (7) and stack ({5, 6}) args are always live.
 		{
 			func() int {
 				poisonStack() // poison arg area to make output deterministic
 				return testTracebackArgs9(1, 2, 3, 4, [2]int{5, 6}, 7)
 			},
 			abiSel(
 				"testTracebackArgs9(0x1, 0xffffffff?, 0x3, 0xff?, {0x5, 0x6}, 0x7)",
 				"testTracebackArgs9(0x1, 0x2, 0x3, 0x4, {0x5, 0x6}, 0x7)"),
 		},
 		// No live.
 		// (Note: this assume at least 5 int registers if register ABI is used.)
 		{
 			func() int {
 				poisonStack() // poison arg area to make output deterministic
 				return testTracebackArgs10(1, 2, 3, 4, 5)
 			},
 			abiSel(
 				"testTracebackArgs10(0xffffffff?, 0xffffffff?, 0xffffffff?, 0xffffffff?, 0xffffffff?)",
 				"testTracebackArgs10(0x1, 0x2, 0x3, 0x4, 0x5)"),
 		},
 		// Conditional spills.
 		// Spill in conditional, not executed.
 		{
 			func() int {
 				poisonStack() // poison arg area to make output deterministic
 				return testTracebackArgs11a(1, 2, 3)
 			},
 			abiSel(
 				"testTracebackArgs11a(0xffffffff?, 0xffffffff?, 0xffffffff?)",
 				"testTracebackArgs11a(0x1, 0x2, 0x3)"),
 		},
 		// 2 spills in conditional, not executed; 3 spills in conditional, executed, but not statically known.
 		// So print 0x3?.
 		{
 			func() int {
 				poisonStack() // poison arg area to make output deterministic
 				return testTracebackArgs11b(1, 2, 3, 4)
 			},
 			abiSel(
 				"testTracebackArgs11b(0xffffffff?, 0xffffffff?, 0x3?, 0x4)",
 				"testTracebackArgs11b(0x1, 0x2, 0x3, 0x4)"),
 		},
 	}
 	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 int) int {
 	n := runtime.Stack(testTracebackArgsBuf[:], false)
 	if a < 0 {
 		// use in-reg args to keep them alive
 		return a + b + c + d + e
 	}
 	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
 }

 //go:noinline
 func testTracebackArgs6a(a, b, c, d, e, f, g, h, i, j 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
 	}
 	return n
 }

 //go:noinline
 func testTracebackArgs6b(a, b, c, d, e, f, g, h, i, j, k 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
 	}
 	return n
 }

 //go:noinline
 func testTracebackArgs7a(a [10]int) int {
 	n := runtime.Stack(testTracebackArgsBuf[:], false)
 	if a[0] < 0 {
 		// use in-reg args to keep them alive
 		return a[1] + a[2] + a[3] + a[4] + a[5] + a[6] + a[7] + a[8] + a[9]
 	}
 	return n
 }

 //go:noinline
 func testTracebackArgs7b(a [11]int) int {
 	n := runtime.Stack(testTracebackArgsBuf[:], false)
 	if a[0] < 0 {
 		// use in-reg args to keep them alive
 		return a[1] + a[2] + a[3] + a[4] + a[5] + a[6] + a[7] + a[8] + a[9] + a[10]
 	}
 	return n
 }

 //go:noinline
 func testTracebackArgs7c(a [10]int, b int) int {
 	n := runtime.Stack(testTracebackArgsBuf[:], false)
 	if a[0] < 0 {
 		// use in-reg args to keep them alive
 		return a[1] + a[2] + a[3] + a[4] + a[5] + a[6] + a[7] + a[8] + a[9] + b
 	}
 	return n
 }

 //go:noinline
 func testTracebackArgs7d(a [11]int, b int) int {
 	n := runtime.Stack(testTracebackArgsBuf[:], false)
 	if a[0] < 0 {
 		// use in-reg args to keep them alive
 		return a[1] + a[2] + a[3] + a[4] + a[5] + a[6] + a[7] + a[8] + a[9] + a[10] + b
 	}
 	return n
 }

 type testArgsType8a struct {
 	a, b, c, d, e, f, g, h int
 	i                      [2]int
 }
 type testArgsType8b struct {
 	a, b, c, d, e, f, g, h int
 	i                      [3]int
 }
 type testArgsType8c struct {
 	a, b, c, d, e, f, g, h int
 	i                      [2]int
 	j                      int
 }
 type testArgsType8d struct {
 	a, b, c, d, e, f, g, h int
 	i                      [3]int
 	j                      int
 }

 //go:noinline
 func testTracebackArgs8a(a testArgsType8a) int {
 	n := runtime.Stack(testTracebackArgsBuf[:], false)
 	if a.a < 0 {
 		// use in-reg args to keep them alive
 		return a.b + a.c + a.d + a.e + a.f + a.g + a.h + a.i[0] + a.i[1]
 	}
 	return n
 }

 //go:noinline
 func testTracebackArgs8b(a testArgsType8b) int {
 	n := runtime.Stack(testTracebackArgsBuf[:], false)
 	if a.a < 0 {
 		// use in-reg args to keep them alive
 		return a.b + a.c + a.d + a.e + a.f + a.g + a.h + a.i[0] + a.i[1] + a.i[2]
 	}
 	return n
 }

 //go:noinline
 func testTracebackArgs8c(a testArgsType8c) int {
 	n := runtime.Stack(testTracebackArgsBuf[:], false)
 	if a.a < 0 {
 		// use in-reg args to keep them alive
 		return a.b + a.c + a.d + a.e + a.f + a.g + a.h + a.i[0] + a.i[1] + a.j
 	}
 	return n
 }

 //go:noinline
 func testTracebackArgs8d(a testArgsType8d) int {
 	n := runtime.Stack(testTracebackArgsBuf[:], false)
 	if a.a < 0 {
 		// use in-reg args to keep them alive
 		return a.b + a.c + a.d + a.e + a.f + a.g + a.h + a.i[0] + a.i[1] + a.i[2] + a.j
 	}
 	return n
 }

 // nosplit to avoid preemption or morestack spilling registers.
 //
 //go:nosplit
 //go:noinline
 func testTracebackArgs9(a int64, b int32, c int16, d int8, x [2]int, y int) int {
 	if a < 0 {
 		println(&y) // take address, make y live, even if no longer used at traceback
 	}
 	n := runtime.Stack(testTracebackArgsBuf[:], false)
 	if a < 0 {
 		// use half of in-reg args to keep them alive, the other half are dead
 		return int(a) + int(c)
 	}
 	return n
 }

 // nosplit to avoid preemption or morestack spilling registers.
 //
 //go:nosplit
 //go:noinline
 func testTracebackArgs10(a, b, c, d, e int32) int {
 	// no use of any args
 	return runtime.Stack(testTracebackArgsBuf[:], false)
 }

 // norace to avoid race instrumentation changing spill locations.
 // nosplit to avoid preemption or morestack spilling registers.
 //
 //go:norace
 //go:nosplit
 //go:noinline
 func testTracebackArgs11a(a, b, c int32) int {
 	if a < 0 {
 		println(a, b, c) // spill in a conditional, may not execute
 	}
 	if b < 0 {
 		return int(a + b + c)
 	}
 	return runtime.Stack(testTracebackArgsBuf[:], false)
 }

 // norace to avoid race instrumentation changing spill locations.
 // nosplit to avoid preemption or morestack spilling registers.
 //
 //go:norace
 //go:nosplit
 //go:noinline
 func testTracebackArgs11b(a, b, c, d int32) int {
 	var x int32
 	if a < 0 {
 		print() // spill b in a conditional
 		x = b
 	} else {
 		print() // spill c in a conditional
 		x = c
 	}
 	if d < 0 { // d is always needed
 		return int(x + d)
 	}
 	return runtime.Stack(testTracebackArgsBuf[:], false)
 }

 // Poison the arg area with deterministic values.
 //
 //go:noinline
 func poisonStack() [20]int {
 	return [20]int{-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1}
 }
	// 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"
	"internal/goexperiment"
	"internal/testenv"
	"runtime"
	"strings"
	"testing"
	)

	var testTracebackArgsBuf [1000]byte

	func TestTracebackArgs(t *testing.T) {
	if *flagQuick {
	t.Skip("-quick")
	}
	optimized := !strings.HasSuffix(testenv.Builder(), "-noopt")
	abiSel := func(x, y string) string {
	// select expected output based on ABI
	// In noopt build we always spill arguments so the output is the same as stack ABI.
	if optimized && goexperiment.RegabiArgs {
	return x
	}
	return y
	}

	tests := []struct {
	fn func() int
	expect string
	}{
	// simple ints
	{
	func() int { return testTracebackArgs1(1, 2, 3, 4, 5) },
	"testTracebackArgs1(0x1, 0x2, 0x3, 0x4, 0x5)",
	},
	// 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, {}, {{}, {}}}, {}, {}, {}, {}, {}, ...)",
	},

	// edge cases for ...
	// no ... for 10 args
	{
	func() int { return testTracebackArgs6a(1, 2, 3, 4, 5, 6, 7, 8, 9, 10) },
	"testTracebackArgs6a(0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa)",
	},
	// has ... for 11 args
	{
	func() int { return testTracebackArgs6b(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11) },
	"testTracebackArgs6b(0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa, ...)",
	},
	// no ... for aggregates with 10 words
	{
	func() int { return testTracebackArgs7a([10]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}) },
	"testTracebackArgs7a({0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa})",
	},
	// has ... for aggregates with 11 words
	{
	func() int { return testTracebackArgs7b([11]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}) },
	"testTracebackArgs7b({0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa, ...})",
	},
	// no ... for aggregates, but with more args
	{
	func() int { return testTracebackArgs7c([10]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, 11) },
	"testTracebackArgs7c({0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa}, ...)",
	},
	// has ... for aggregates and also for more args
	{
	func() int { return testTracebackArgs7d([11]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}, 12) },
	"testTracebackArgs7d({0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa, ...}, ...)",
	},
	// nested aggregates, no ...
	{
	func() int { return testTracebackArgs8a(testArgsType8a{1, 2, 3, 4, 5, 6, 7, 8, [2]int{9, 10}}) },
	"testTracebackArgs8a({0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, {0x9, 0xa}})",
	},
	// nested aggregates, ... in inner but not outer
	{
	func() int { return testTracebackArgs8b(testArgsType8b{1, 2, 3, 4, 5, 6, 7, 8, [3]int{9, 10, 11}}) },
	"testTracebackArgs8b({0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, {0x9, 0xa, ...}})",
	},
	// nested aggregates, ... in outer but not inner
	{
	func() int { return testTracebackArgs8c(testArgsType8c{1, 2, 3, 4, 5, 6, 7, 8, [2]int{9, 10}, 11}) },
	"testTracebackArgs8c({0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, {0x9, 0xa}, ...})",
	},
	// nested aggregates, ... in both inner and outer
	{
	func() int { return testTracebackArgs8d(testArgsType8d{1, 2, 3, 4, 5, 6, 7, 8, [3]int{9, 10, 11}, 12}) },
	"testTracebackArgs8d({0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, {0x9, 0xa, ...}, ...})",
	},

	// Register argument liveness.
	// 1, 3 are used and live, 2, 4 are dead (in register ABI).
	// Address-taken (7) and stack ({5, 6}) args are always live.
	{
	func() int {
	poisonStack() // poison arg area to make output deterministic
	return testTracebackArgs9(1, 2, 3, 4, [2]int{5, 6}, 7)
	},
	abiSel(
	"testTracebackArgs9(0x1, 0xffffffff?, 0x3, 0xff?, {0x5, 0x6}, 0x7)",
	"testTracebackArgs9(0x1, 0x2, 0x3, 0x4, {0x5, 0x6}, 0x7)"),
	},
	// No live.
	// (Note: this assume at least 5 int registers if register ABI is used.)
	{
	func() int {
	poisonStack() // poison arg area to make output deterministic
	return testTracebackArgs10(1, 2, 3, 4, 5)
	},
	abiSel(
	"testTracebackArgs10(0xffffffff?, 0xffffffff?, 0xffffffff?, 0xffffffff?, 0xffffffff?)",
	"testTracebackArgs10(0x1, 0x2, 0x3, 0x4, 0x5)"),
	},
	// Conditional spills.
	// Spill in conditional, not executed.
	{
	func() int {
	poisonStack() // poison arg area to make output deterministic
	return testTracebackArgs11a(1, 2, 3)
	},
	abiSel(
	"testTracebackArgs11a(0xffffffff?, 0xffffffff?, 0xffffffff?)",
	"testTracebackArgs11a(0x1, 0x2, 0x3)"),
	},
	// 2 spills in conditional, not executed; 3 spills in conditional, executed, but not statically known.
	// So print 0x3?.
	{
	func() int {
	poisonStack() // poison arg area to make output deterministic
	return testTracebackArgs11b(1, 2, 3, 4)
	},
	abiSel(
	"testTracebackArgs11b(0xffffffff?, 0xffffffff?, 0x3?, 0x4)",
	"testTracebackArgs11b(0x1, 0x2, 0x3, 0x4)"),
	},
	}
	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 int) int {
	n := runtime.Stack(testTracebackArgsBuf[:], false)
	if a < 0 {
	// use in-reg args to keep them alive
	return a + b + c + d + e
	}
	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
	}

	//go:noinline
	func testTracebackArgs6a(a, b, c, d, e, f, g, h, i, j 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
	}
	return n
	}

	//go:noinline
	func testTracebackArgs6b(a, b, c, d, e, f, g, h, i, j, k 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
	}
	return n
	}

	//go:noinline
	func testTracebackArgs7a(a [10]int) int {
	n := runtime.Stack(testTracebackArgsBuf[:], false)
	if a[0] < 0 {
	// use in-reg args to keep them alive
	return a[1] + a[2] + a[3] + a[4] + a[5] + a[6] + a[7] + a[8] + a[9]
	}
	return n
	}

	//go:noinline
	func testTracebackArgs7b(a [11]int) int {
	n := runtime.Stack(testTracebackArgsBuf[:], false)
	if a[0] < 0 {
	// use in-reg args to keep them alive
	return a[1] + a[2] + a[3] + a[4] + a[5] + a[6] + a[7] + a[8] + a[9] + a[10]
	}
	return n
	}

	//go:noinline
	func testTracebackArgs7c(a [10]int, b int) int {
	n := runtime.Stack(testTracebackArgsBuf[:], false)
	if a[0] < 0 {
	// use in-reg args to keep them alive
	return a[1] + a[2] + a[3] + a[4] + a[5] + a[6] + a[7] + a[8] + a[9] + b
	}
	return n
	}

	//go:noinline
	func testTracebackArgs7d(a [11]int, b int) int {
	n := runtime.Stack(testTracebackArgsBuf[:], false)
	if a[0] < 0 {
	// use in-reg args to keep them alive
	return a[1] + a[2] + a[3] + a[4] + a[5] + a[6] + a[7] + a[8] + a[9] + a[10] + b
	}
	return n
	}

	type testArgsType8a struct {
	a, b, c, d, e, f, g, h int
	i [2]int
	}
	type testArgsType8b struct {
	a, b, c, d, e, f, g, h int
	i [3]int
	}
	type testArgsType8c struct {
	a, b, c, d, e, f, g, h int
	i [2]int
	j int
	}
	type testArgsType8d struct {
	a, b, c, d, e, f, g, h int
	i [3]int
	j int
	}

	//go:noinline
	func testTracebackArgs8a(a testArgsType8a) int {
	n := runtime.Stack(testTracebackArgsBuf[:], false)
	if a.a < 0 {
	// use in-reg args to keep them alive
	return a.b + a.c + a.d + a.e + a.f + a.g + a.h + a.i[0] + a.i[1]
	}
	return n
	}

	//go:noinline
	func testTracebackArgs8b(a testArgsType8b) int {
	n := runtime.Stack(testTracebackArgsBuf[:], false)
	if a.a < 0 {
	// use in-reg args to keep them alive
	return a.b + a.c + a.d + a.e + a.f + a.g + a.h + a.i[0] + a.i[1] + a.i[2]
	}
	return n
	}

	//go:noinline
	func testTracebackArgs8c(a testArgsType8c) int {
	n := runtime.Stack(testTracebackArgsBuf[:], false)
	if a.a < 0 {
	// use in-reg args to keep them alive
	return a.b + a.c + a.d + a.e + a.f + a.g + a.h + a.i[0] + a.i[1] + a.j
	}
	return n
	}

	//go:noinline
	func testTracebackArgs8d(a testArgsType8d) int {
	n := runtime.Stack(testTracebackArgsBuf[:], false)
	if a.a < 0 {
	// use in-reg args to keep them alive
	return a.b + a.c + a.d + a.e + a.f + a.g + a.h + a.i[0] + a.i[1] + a.i[2] + a.j
	}
	return n
	}

	// nosplit to avoid preemption or morestack spilling registers.
	//
	//go:nosplit
	//go:noinline
	func testTracebackArgs9(a int64, b int32, c int16, d int8, x [2]int, y int) int {
	if a < 0 {
	println(&y) // take address, make y live, even if no longer used at traceback
	}
	n := runtime.Stack(testTracebackArgsBuf[:], false)
	if a < 0 {
	// use half of in-reg args to keep them alive, the other half are dead
	return int(a) + int(c)
	}
	return n
	}

	// nosplit to avoid preemption or morestack spilling registers.
	//
	//go:nosplit
	//go:noinline
	func testTracebackArgs10(a, b, c, d, e int32) int {
	// no use of any args
	return runtime.Stack(testTracebackArgsBuf[:], false)
	}

	// norace to avoid race instrumentation changing spill locations.
	// nosplit to avoid preemption or morestack spilling registers.
	//
	//go:norace
	//go:nosplit
	//go:noinline
	func testTracebackArgs11a(a, b, c int32) int {
	if a < 0 {
	println(a, b, c) // spill in a conditional, may not execute
	}
	if b < 0 {
	return int(a + b + c)
	}
	return runtime.Stack(testTracebackArgsBuf[:], false)
	}

	// norace to avoid race instrumentation changing spill locations.
	// nosplit to avoid preemption or morestack spilling registers.
	//
	//go:norace
	//go:nosplit
	//go:noinline
	func testTracebackArgs11b(a, b, c, d int32) int {
	var x int32
	if a < 0 {
	print() // spill b in a conditional
	x = b
	} else {
	print() // spill c in a conditional
	x = c
	}
	if d < 0 { // d is always needed
	return int(x + d)
	}
	return runtime.Stack(testTracebackArgsBuf[:], false)
	}

	// Poison the arg area with deterministic values.
	//
	//go:noinline
	func poisonStack() [20]int {
	return [20]int{-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1}
	}