blob: 3c19c513b65a61d2a69c4a3e14f7e600f6d82075 [file] [log] [blame]
// +build amd64
// errorcheck -0 -d=ssa/prove/debug=1
// Copyright 2016 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 main
import "math"
func f0(a []int) int {
a[0] = 1
a[0] = 1 // ERROR "Proved IsInBounds$"
a[6] = 1
a[6] = 1 // ERROR "Proved IsInBounds$"
a[5] = 1 // ERROR "Proved IsInBounds$"
a[5] = 1 // ERROR "Proved IsInBounds$"
return 13
}
func f1(a []int) int {
if len(a) <= 5 {
return 18
}
a[0] = 1 // ERROR "Proved IsInBounds$"
a[0] = 1 // ERROR "Proved IsInBounds$"
a[6] = 1
a[6] = 1 // ERROR "Proved IsInBounds$"
a[5] = 1 // ERROR "Proved IsInBounds$"
a[5] = 1 // ERROR "Proved IsInBounds$"
return 26
}
func f1b(a []int, i int, j uint) int {
if i >= 0 && i < len(a) {
return a[i] // ERROR "Proved IsInBounds$"
}
if i >= 10 && i < len(a) {
return a[i] // ERROR "Proved IsInBounds$"
}
if i >= 10 && i < len(a) {
return a[i] // ERROR "Proved IsInBounds$"
}
if i >= 10 && i < len(a) {
return a[i-10] // ERROR "Proved IsInBounds$"
}
if j < uint(len(a)) {
return a[j] // ERROR "Proved IsInBounds$"
}
return 0
}
func f1c(a []int, i int64) int {
c := uint64(math.MaxInt64 + 10) // overflows int
d := int64(c)
if i >= d && i < int64(len(a)) {
// d overflows, should not be handled.
return a[i]
}
return 0
}
func f2(a []int) int {
for i := range a { // ERROR "Induction variable: limits \[0,\?\), increment 1$"
a[i+1] = i
a[i+1] = i // ERROR "Proved IsInBounds$"
}
return 34
}
func f3(a []uint) int {
for i := uint(0); i < uint(len(a)); i++ {
a[i] = i // ERROR "Proved IsInBounds$"
}
return 41
}
func f4a(a, b, c int) int {
if a < b {
if a == b { // ERROR "Disproved Eq64$"
return 47
}
if a > b { // ERROR "Disproved Less64$"
return 50
}
if a < b { // ERROR "Proved Less64$"
return 53
}
// We can't get to this point and prove knows that, so
// there's no message for the next (obvious) branch.
if a != a {
return 56
}
return 61
}
return 63
}
func f4b(a, b, c int) int {
if a <= b {
if a >= b {
if a == b { // ERROR "Proved Eq64$"
return 70
}
return 75
}
return 77
}
return 79
}
func f4c(a, b, c int) int {
if a <= b {
if a >= b {
if a != b { // ERROR "Disproved Neq64$"
return 73
}
return 75
}
return 77
}
return 79
}
func f4d(a, b, c int) int {
if a < b {
if a < c {
if a < b { // ERROR "Proved Less64$"
if a < c { // ERROR "Proved Less64$"
return 87
}
return 89
}
return 91
}
return 93
}
return 95
}
func f4e(a, b, c int) int {
if a < b {
if b > a { // ERROR "Proved Less64$"
return 101
}
return 103
}
return 105
}
func f4f(a, b, c int) int {
if a <= b {
if b > a {
if b == a { // ERROR "Disproved Eq64$"
return 112
}
return 114
}
if b >= a { // ERROR "Proved Leq64$"
if b == a { // ERROR "Proved Eq64$"
return 118
}
return 120
}
return 122
}
return 124
}
func f5(a, b uint) int {
if a == b {
if a <= b { // ERROR "Proved Leq64U$"
return 130
}
return 132
}
return 134
}
// These comparisons are compile time constants.
func f6a(a uint8) int {
if a < a { // ERROR "Disproved Less8U$"
return 140
}
return 151
}
func f6b(a uint8) int {
if a < a { // ERROR "Disproved Less8U$"
return 140
}
return 151
}
func f6x(a uint8) int {
if a > a { // ERROR "Disproved Less8U$"
return 143
}
return 151
}
func f6d(a uint8) int {
if a <= a { // ERROR "Proved Leq8U$"
return 146
}
return 151
}
func f6e(a uint8) int {
if a >= a { // ERROR "Proved Leq8U$"
return 149
}
return 151
}
func f7(a []int, b int) int {
if b < len(a) {
a[b] = 3
if b < len(a) { // ERROR "Proved Less64$"
a[b] = 5 // ERROR "Proved IsInBounds$"
}
}
return 161
}
func f8(a, b uint) int {
if a == b {
return 166
}
if a > b {
return 169
}
if a < b { // ERROR "Proved Less64U$"
return 172
}
return 174
}
func f9(a, b bool) int {
if a {
return 1
}
if a || b { // ERROR "Disproved Arg$"
return 2
}
return 3
}
func f10(a string) int {
n := len(a)
// We optimize comparisons with small constant strings (see cmd/compile/internal/gc/walk.go),
// so this string literal must be long.
if a[:n>>1] == "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" {
return 0
}
return 1
}
func f11a(a []int, i int) {
useInt(a[i])
useInt(a[i]) // ERROR "Proved IsInBounds$"
}
func f11b(a []int, i int) {
useSlice(a[i:])
useSlice(a[i:]) // ERROR "Proved IsSliceInBounds$"
}
func f11c(a []int, i int) {
useSlice(a[:i])
useSlice(a[:i]) // ERROR "Proved IsSliceInBounds$"
}
func f11d(a []int, i int) {
useInt(a[2*i+7])
useInt(a[2*i+7]) // ERROR "Proved IsInBounds$"
}
func f12(a []int, b int) {
useSlice(a[:b])
}
func f13a(a, b, c int, x bool) int {
if a > 12 {
if x {
if a < 12 { // ERROR "Disproved Less64$"
return 1
}
}
if x {
if a <= 12 { // ERROR "Disproved Leq64$"
return 2
}
}
if x {
if a == 12 { // ERROR "Disproved Eq64$"
return 3
}
}
if x {
if a >= 12 { // ERROR "Proved Leq64$"
return 4
}
}
if x {
if a > 12 { // ERROR "Proved Less64$"
return 5
}
}
return 6
}
return 0
}
func f13b(a int, x bool) int {
if a == -9 {
if x {
if a < -9 { // ERROR "Disproved Less64$"
return 7
}
}
if x {
if a <= -9 { // ERROR "Proved Leq64$"
return 8
}
}
if x {
if a == -9 { // ERROR "Proved Eq64$"
return 9
}
}
if x {
if a >= -9 { // ERROR "Proved Leq64$"
return 10
}
}
if x {
if a > -9 { // ERROR "Disproved Less64$"
return 11
}
}
return 12
}
return 0
}
func f13c(a int, x bool) int {
if a < 90 {
if x {
if a < 90 { // ERROR "Proved Less64$"
return 13
}
}
if x {
if a <= 90 { // ERROR "Proved Leq64$"
return 14
}
}
if x {
if a == 90 { // ERROR "Disproved Eq64$"
return 15
}
}
if x {
if a >= 90 { // ERROR "Disproved Leq64$"
return 16
}
}
if x {
if a > 90 { // ERROR "Disproved Less64$"
return 17
}
}
return 18
}
return 0
}
func f13d(a int) int {
if a < 5 {
if a < 9 { // ERROR "Proved Less64$"
return 1
}
}
return 0
}
func f13e(a int) int {
if a > 9 {
if a > 5 { // ERROR "Proved Less64$"
return 1
}
}
return 0
}
func f13f(a int64) int64 {
if a > math.MaxInt64 {
if a == 0 { // ERROR "Disproved Eq64$"
return 1
}
}
return 0
}
func f13g(a int) int {
if a < 3 {
return 5
}
if a > 3 {
return 6
}
if a == 3 { // ERROR "Proved Eq64$"
return 7
}
return 8
}
func f13h(a int) int {
if a < 3 {
if a > 1 {
if a == 2 { // ERROR "Proved Eq64$"
return 5
}
}
}
return 0
}
func f13i(a uint) int {
if a == 0 {
return 1
}
if a > 0 { // ERROR "Proved Less64U$"
return 2
}
return 3
}
func f14(p, q *int, a []int) {
// This crazy ordering usually gives i1 the lowest value ID,
// j the middle value ID, and i2 the highest value ID.
// That used to confuse CSE because it ordered the args
// of the two + ops below differently.
// That in turn foiled bounds check elimination.
i1 := *p
j := *q
i2 := *p
useInt(a[i1+j])
useInt(a[i2+j]) // ERROR "Proved IsInBounds$"
}
func f15(s []int, x int) {
useSlice(s[x:])
useSlice(s[:x]) // ERROR "Proved IsSliceInBounds$"
}
func f16(s []int) []int {
if len(s) >= 10 {
return s[:10] // ERROR "Proved IsSliceInBounds$"
}
return nil
}
func f17(b []int) {
for i := 0; i < len(b); i++ { // ERROR "Induction variable: limits \[0,\?\), increment 1$"
// This tests for i <= cap, which we can only prove
// using the derived relation between len and cap.
// This depends on finding the contradiction, since we
// don't query this condition directly.
useSlice(b[:i]) // ERROR "Proved IsSliceInBounds$"
}
}
func f18(b []int, x int, y uint) {
_ = b[x]
_ = b[y]
if x > len(b) { // ERROR "Disproved Less64$"
return
}
if y > uint(len(b)) { // ERROR "Disproved Less64U$"
return
}
if int(y) > len(b) { // ERROR "Disproved Less64$"
return
}
}
func f19() (e int64, err error) {
// Issue 29502: slice[:0] is incorrectly disproved.
var stack []int64
stack = append(stack, 123)
if len(stack) > 1 {
panic("too many elements")
}
last := len(stack) - 1
e = stack[last]
// Buggy compiler prints "Disproved Leq64" for the next line.
stack = stack[:last] // ERROR "Proved IsSliceInBounds"
return e, nil
}
func sm1(b []int, x int) {
// Test constant argument to slicemask.
useSlice(b[2:8]) // ERROR "Proved slicemask not needed$"
// Test non-constant argument with known limits.
if cap(b) > 10 {
useSlice(b[2:])
}
}
func lim1(x, y, z int) {
// Test relations between signed and unsigned limits.
if x > 5 {
if uint(x) > 5 { // ERROR "Proved Less64U$"
return
}
}
if y >= 0 && y < 4 {
if uint(y) > 4 { // ERROR "Disproved Less64U$"
return
}
if uint(y) < 5 { // ERROR "Proved Less64U$"
return
}
}
if z < 4 {
if uint(z) > 4 { // Not provable without disjunctions.
return
}
}
}
// fence1–4 correspond to the four fence-post implications.
func fence1(b []int, x, y int) {
// Test proofs that rely on fence-post implications.
if x+1 > y {
if x < y { // ERROR "Disproved Less64$"
return
}
}
if len(b) < cap(b) {
// This eliminates the growslice path.
b = append(b, 1) // ERROR "Disproved Less64U$"
}
}
func fence2(x, y int) {
if x-1 < y {
if x > y { // ERROR "Disproved Less64$"
return
}
}
}
func fence3(b, c []int, x, y int64) {
if x-1 >= y {
if x <= y { // Can't prove because x may have wrapped.
return
}
}
if x != math.MinInt64 && x-1 >= y {
if x <= y { // ERROR "Disproved Leq64$"
return
}
}
c[len(c)-1] = 0 // Can't prove because len(c) might be 0
if n := len(b); n > 0 {
b[n-1] = 0 // ERROR "Proved IsInBounds$"
}
}
func fence4(x, y int64) {
if x >= y+1 {
if x <= y {
return
}
}
if y != math.MaxInt64 && x >= y+1 {
if x <= y { // ERROR "Disproved Leq64$"
return
}
}
}
// Check transitive relations
func trans1(x, y int64) {
if x > 5 {
if y > x {
if y > 2 { // ERROR "Proved Less64$"
return
}
} else if y == x {
if y > 5 { // ERROR "Proved Less64$"
return
}
}
}
if x >= 10 {
if y > x {
if y > 10 { // ERROR "Proved Less64$"
return
}
}
}
}
func trans2(a, b []int, i int) {
if len(a) != len(b) {
return
}
_ = a[i]
_ = b[i] // ERROR "Proved IsInBounds$"
}
func trans3(a, b []int, i int) {
if len(a) > len(b) {
return
}
_ = a[i]
_ = b[i] // ERROR "Proved IsInBounds$"
}
// Derived from nat.cmp
func natcmp(x, y []uint) (r int) {
m := len(x)
n := len(y)
if m != n || m == 0 {
return
}
i := m - 1
for i > 0 && // ERROR "Induction variable: limits \(0,\?\], increment 1$"
x[i] == // ERROR "Proved IsInBounds$"
y[i] { // ERROR "Proved IsInBounds$"
i--
}
switch {
case x[i] < // todo, cannot prove this because it's dominated by i<=0 || x[i]==y[i]
y[i]: // ERROR "Proved IsInBounds$"
r = -1
case x[i] > // ERROR "Proved IsInBounds$"
y[i]: // ERROR "Proved IsInBounds$"
r = 1
}
return
}
func suffix(s, suffix string) bool {
// todo, we're still not able to drop the bound check here in the general case
return len(s) >= len(suffix) && s[len(s)-len(suffix):] == suffix
}
func constsuffix(s string) bool {
return suffix(s, "abc") // ERROR "Proved IsSliceInBounds$"
}
// oforuntil tests the pattern created by OFORUNTIL blocks. These are
// handled by addLocalInductiveFacts rather than findIndVar.
func oforuntil(b []int) {
i := 0
if len(b) > i {
top:
// TODO: remove the todo of next line once we complete the following optimization of CL 244579
// println(b[i]) // todo: ERROR "Induction variable: limits \[0,\?\), increment 1$" "Proved IsInBounds$"
i++
if i < len(b) {
goto top
}
}
}
func atexit(foobar []func()) {
for i := len(foobar) - 1; i >= 0; i-- { // ERROR "Induction variable: limits \[0,\?\], increment 1"
f := foobar[i]
foobar = foobar[:i] // ERROR "IsSliceInBounds"
f()
}
}
func make1(n int) []int {
s := make([]int, n)
for i := 0; i < n; i++ { // ERROR "Induction variable: limits \[0,\?\), increment 1"
s[i] = 1 // ERROR "Proved IsInBounds$"
}
return s
}
func make2(n int) []int {
s := make([]int, n)
for i := range s { // ERROR "Induction variable: limits \[0,\?\), increment 1"
s[i] = 1 // ERROR "Proved IsInBounds$"
}
return s
}
// The range tests below test the index variable of range loops.
// range1 compiles to the "efficiently indexable" form of a range loop.
func range1(b []int) {
for i, v := range b { // ERROR "Induction variable: limits \[0,\?\), increment 1$"
b[i] = v + 1 // ERROR "Proved IsInBounds$"
if i < len(b) { // ERROR "Proved Less64$"
println("x")
}
if i >= 0 { // ERROR "Proved Leq64$"
println("x")
}
}
}
// range2 elements are larger, so they use the general form of a range loop.
func range2(b [][32]int) {
for i, v := range b {
// TODO: remove the todo of next line once we complete the following optimization of CL 244579
b[i][0] = v[0] + 1 // todo: ERROR "Induction variable: limits \[0,\?\), increment 1$" "Proved IsInBounds$"
if i < len(b) { // ERROR "Proved Less64$"
println("x")
}
if i >= 0 { // ERROR "Proved Leq64$"
println("x")
}
}
}
// signhint1-2 test whether the hint (int >= 0) is propagated into the loop.
func signHint1(i int, data []byte) {
if i >= 0 {
for i < len(data) { // ERROR "Induction variable: limits \[\?,\?\), increment 1$"
_ = data[i] // ERROR "Proved IsInBounds$"
i++
}
}
}
func signHint2(b []byte, n int) {
if n < 0 {
panic("")
}
_ = b[25]
for i := n; i <= 25; i++ { // ERROR "Induction variable: limits \[\?,25\], increment 1$"
b[i] = 123 // ERROR "Proved IsInBounds$"
}
}
// indexGT0 tests whether prove learns int index >= 0 from bounds check.
func indexGT0(b []byte, n int) {
_ = b[n]
_ = b[25]
for i := n; i <= 25; i++ { // ERROR "Induction variable: limits \[\?,25\], increment 1$"
b[i] = 123 // ERROR "Proved IsInBounds$"
}
}
// Induction variable in unrolled loop.
func unrollUpExcl(a []int) int {
var i, x int
for i = 0; i < len(a)-1; i += 2 { // ERROR "Induction variable: limits \[0,\?\), increment 2$"
x += a[i] // ERROR "Proved IsInBounds$"
x += a[i+1]
}
if i == len(a)-1 {
x += a[i]
}
return x
}
// Induction variable in unrolled loop.
func unrollUpIncl(a []int) int {
var i, x int
for i = 0; i <= len(a)-2; i += 2 { // ERROR "Induction variable: limits \[0,\?\], increment 2$"
x += a[i]
x += a[i+1]
}
if i == len(a)-1 {
x += a[i]
}
return x
}
// Induction variable in unrolled loop.
func unrollDownExcl0(a []int) int {
var i, x int
for i = len(a) - 1; i > 0; i -= 2 { // ERROR "Induction variable: limits \(0,\?\], increment 2$"
x += a[i] // ERROR "Proved IsInBounds$"
x += a[i-1] // ERROR "Proved IsInBounds$"
}
if i == 0 {
x += a[i]
}
return x
}
// Induction variable in unrolled loop.
func unrollDownExcl1(a []int) int {
var i, x int
for i = len(a) - 1; i >= 1; i -= 2 { // ERROR "Induction variable: limits \[1,\?\], increment 2$"
x += a[i] // ERROR "Proved IsInBounds$"
x += a[i-1] // ERROR "Proved IsInBounds$"
}
if i == 0 {
x += a[i]
}
return x
}
// Induction variable in unrolled loop.
func unrollDownInclStep(a []int) int {
var i, x int
for i = len(a); i >= 2; i -= 2 { // ERROR "Induction variable: limits \[2,\?\], increment 2$"
x += a[i-1] // ERROR "Proved IsInBounds$"
x += a[i-2]
}
if i == 1 {
x += a[i-1]
}
return x
}
// Not an induction variable (step too large)
func unrollExclStepTooLarge(a []int) int {
var i, x int
for i = 0; i < len(a)-1; i += 3 {
x += a[i]
x += a[i+1]
}
if i == len(a)-1 {
x += a[i]
}
return x
}
// Not an induction variable (step too large)
func unrollInclStepTooLarge(a []int) int {
var i, x int
for i = 0; i <= len(a)-2; i += 3 {
x += a[i]
x += a[i+1]
}
if i == len(a)-1 {
x += a[i]
}
return x
}
// Not an induction variable (min too small, iterating down)
func unrollDecMin(a []int) int {
var i, x int
for i = len(a); i >= math.MinInt64; i -= 2 {
x += a[i-1]
x += a[i-2]
}
if i == 1 { // ERROR "Disproved Eq64$"
x += a[i-1]
}
return x
}
// Not an induction variable (min too small, iterating up -- perhaps could allow, but why bother?)
func unrollIncMin(a []int) int {
var i, x int
for i = len(a); i >= math.MinInt64; i += 2 {
x += a[i-1]
x += a[i-2]
}
if i == 1 { // ERROR "Disproved Eq64$"
x += a[i-1]
}
return x
}
// The 4 xxxxExtNto64 functions below test whether prove is looking
// through value-preserving sign/zero extensions of index values (issue #26292).
// Look through all extensions
func signExtNto64(x []int, j8 int8, j16 int16, j32 int32) int {
if len(x) < 22 {
return 0
}
if j8 >= 0 && j8 < 22 {
return x[j8] // ERROR "Proved IsInBounds$"
}
if j16 >= 0 && j16 < 22 {
return x[j16] // ERROR "Proved IsInBounds$"
}
if j32 >= 0 && j32 < 22 {
return x[j32] // ERROR "Proved IsInBounds$"
}
return 0
}
func zeroExtNto64(x []int, j8 uint8, j16 uint16, j32 uint32) int {
if len(x) < 22 {
return 0
}
if j8 >= 0 && j8 < 22 {
return x[j8] // ERROR "Proved IsInBounds$"
}
if j16 >= 0 && j16 < 22 {
return x[j16] // ERROR "Proved IsInBounds$"
}
if j32 >= 0 && j32 < 22 {
return x[j32] // ERROR "Proved IsInBounds$"
}
return 0
}
// Process fence-post implications through 32to64 extensions (issue #29964)
func signExt32to64Fence(x []int, j int32) int {
if x[j] != 0 {
return 1
}
if j > 0 && x[j-1] != 0 { // ERROR "Proved IsInBounds$"
return 1
}
return 0
}
func zeroExt32to64Fence(x []int, j uint32) int {
if x[j] != 0 {
return 1
}
if j > 0 && x[j-1] != 0 { // ERROR "Proved IsInBounds$"
return 1
}
return 0
}
// Ensure that bounds checks with negative indexes are not incorrectly removed.
func negIndex() {
n := make([]int, 1)
for i := -1; i <= 0; i++ { // ERROR "Induction variable: limits \[-1,0\], increment 1$"
n[i] = 1
}
}
func negIndex2(n int) {
a := make([]int, 5)
b := make([]int, 5)
c := make([]int, 5)
for i := -1; i <= 0; i-- {
b[i] = i
n++
if n > 10 {
break
}
}
useSlice(a)
useSlice(c)
}
// Check that prove is zeroing these right shifts of positive ints by bit-width - 1.
// e.g (Rsh64x64 <t> n (Const64 <typ.UInt64> [63])) && ft.isNonNegative(n) -> 0
func sh64(n int64) int64 {
if n < 0 {
return n
}
return n >> 63 // ERROR "Proved Rsh64x64 shifts to zero"
}
func sh32(n int32) int32 {
if n < 0 {
return n
}
return n >> 31 // ERROR "Proved Rsh32x64 shifts to zero"
}
func sh32x64(n int32) int32 {
if n < 0 {
return n
}
return n >> uint64(31) // ERROR "Proved Rsh32x64 shifts to zero"
}
func sh16(n int16) int16 {
if n < 0 {
return n
}
return n >> 15 // ERROR "Proved Rsh16x64 shifts to zero"
}
func sh64noopt(n int64) int64 {
return n >> 63 // not optimized; n could be negative
}
// These cases are division of a positive signed integer by a power of 2.
// The opt pass doesnt have sufficient information to see that n is positive.
// So, instead, opt rewrites the division with a less-than-optimal replacement.
// Prove, which can see that n is nonnegative, cannot see the division because
// opt, an earlier pass, has already replaced it.
// The fix for this issue allows prove to zero a right shift that was added as
// part of the less-than-optimal reqwrite. That change by prove then allows
// lateopt to clean up all the unneccesary parts of the original division
// replacement. See issue #36159.
func divShiftClean(n int) int {
if n < 0 {
return n
}
return n / int(8) // ERROR "Proved Rsh64x64 shifts to zero"
}
func divShiftClean64(n int64) int64 {
if n < 0 {
return n
}
return n / int64(16) // ERROR "Proved Rsh64x64 shifts to zero"
}
func divShiftClean32(n int32) int32 {
if n < 0 {
return n
}
return n / int32(16) // ERROR "Proved Rsh32x64 shifts to zero"
}
//go:noinline
func useInt(a int) {
}
//go:noinline
func useSlice(a []int) {
}
func main() {
}