gc: index bounds tests and fixes
move constant index checking to front end
x[2:1] is a compile-time error now too
R=ken2
CC=golang-dev
https://golang.org/cl/1848056
diff --git a/test/index.go b/test/index.go
new file mode 100644
index 0000000..a91294c
--- /dev/null
+++ b/test/index.go
@@ -0,0 +1,224 @@
+// $G $D/$F.go && $L $F.$A &&
+// ./$A.out -pass 0 >tmp.go && $G tmp.go && $L -o tmp1.$A tmp.$A && ./tmp1.$A &&
+// ./$A.out -pass 1 >tmp.go && errchk $G -e tmp.go &&
+// ./$A.out -pass 2 >tmp.go && errchk $G -e tmp.go
+// rm -f tmp.go
+
+// Copyright 2010 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.
+
+// Generate test of index and slice bounds checks.
+
+package main
+
+import (
+ "bufio"
+ "flag"
+ "fmt"
+ "os"
+)
+
+const prolog = `
+
+package main
+
+import (
+ "runtime"
+)
+
+type quad struct { x, y, z, w int }
+
+const (
+ cj = 11
+ ci int = 12
+ ci32 int32 = 13
+ ci64 int64 = 14
+ ci64big int64 = 1<<31
+ ci64bigger int64 = 1<<32
+ chuge = 1<<100
+
+ cnj = -2
+ cni int = -3
+ cni32 int32 = -4
+ cni64 int64 = -5
+ cni64big int64 = -1<<31
+ cni64bigger int64 = -1<<32
+ cnhuge = -1<<100
+)
+
+var j int = 20
+var i int = 21
+var i32 int32 = 22
+var i64 int64 = 23
+var i64big int64 = 1<<31
+var i64bigger int64 = 1<<32
+var huge uint64 = 1<<64 - 1
+
+var nj int = -10
+var ni int = -11
+var ni32 int32 = -12
+var ni64 int64 = -13
+var ni64big int64 = -1<<31
+var ni64bigger int64 = -1<<32
+var nhuge int64 = -1<<63
+
+var si []int = make([]int, 10)
+var ai [10]int
+var pai *[10]int = &ai
+
+var sq []quad = make([]quad, 10)
+var aq [10]quad
+var paq *[10]quad = &aq
+
+type T struct {
+ si []int
+ ai [10]int
+ pai *[10]int
+ sq []quad
+ aq [10]quad
+ paq *[10]quad
+}
+
+var t = T{si, ai, pai, sq, aq, paq}
+
+var pt = &T{si, ai, pai, sq, aq, paq}
+
+// test that f panics
+func test(f func(), s string) {
+ defer func() {
+ if err := recover(); err == nil {
+ _, file, line, _ := runtime.Caller(2)
+ bug()
+ print(file, ":", line, ": ", s, " did not panic\n")
+ }
+ }()
+ f()
+}
+
+var X interface{}
+func use(y interface{}) {
+ X = y
+}
+
+var didBug = false
+
+func bug() {
+ if !didBug {
+ didBug = true
+ println("BUG")
+ }
+}
+
+func main() {
+`
+
+// Passes:
+// 0 - dynamic checks
+// 1 - static checks of invalid constants (cannot assign to types)
+// 2 - static checks of array bounds
+var pass = flag.Int("pass", 0, "which test (0,1,2)")
+
+func testExpr(b *bufio.Writer, expr string) {
+ if *pass == 0 {
+ fmt.Fprintf(b, "\ttest(func(){use(%s)}, %q)\n", expr, expr)
+ } else {
+ fmt.Fprintf(b, "\tuse(%s) // ERROR \"index|overflow\"\n", expr)
+ }
+}
+
+func main() {
+ b := bufio.NewWriter(os.Stdout)
+
+ flag.Parse()
+
+ if *pass == 0 {
+ fmt.Fprint(b, "// $G $D/$F.go && $L $F.$A && ./$A.out\n\n")
+ } else {
+ fmt.Fprint(b, "// errchk $G -e $D/$F.go\n\n")
+ }
+ fmt.Fprint(b, prolog)
+
+ var choices = [][]string{
+ // Direct value, fetch from struct, fetch from struct pointer.
+ // The last two cases get us to oindex_const_sudo in gsubr.c.
+ []string{"", "t.", "pt."},
+
+ // Array, pointer to array, slice.
+ []string{"a", "pa", "s"},
+
+ // Element is int, element is quad (struct).
+ // This controls whether we end up in gsubr.c (i) or cgen.c (q).
+ []string{"i", "q"},
+
+ // Variable or constant.
+ []string{"", "c"},
+
+ // Positive or negative.
+ []string{"", "n"},
+
+ // Size of index.
+ []string{"j", "i", "i32", "i64", "i64big", "i64bigger", "huge"},
+ }
+
+ forall(choices, func(x []string) {
+ p, a, e, c, n, i := x[0], x[1], x[2], x[3], x[4], x[5]
+
+ // Pass: dynamic=0, static=1, 2.
+ // Which cases should be caught statically?
+ // Only constants, obviously.
+ // Beyond that, must be one of these:
+ // indexing into array or pointer to array
+ // negative constant
+ // large constant
+ thisPass := 0
+ if c == "c" && (a == "a" || a == "pa" || n == "n" || i == "i64big" || i == "i64bigger" || i == "huge") {
+ if i == "huge" {
+ // Due to a detail of 6g's internals,
+ // the huge constant errors happen in an
+ // earlier pass than the others and inhibits
+ // the next pass from running.
+ // So run it as a separate check.
+ thisPass = 1
+ } else {
+ thisPass = 2
+ }
+ }
+
+ // Only print the test case if it is appropriate for this pass.
+ if thisPass == *pass {
+ pae := p+a+e
+ cni := c+n+i
+
+ // Index operation
+ testExpr(b, pae + "[" + cni + "]")
+
+ // Slice operation.
+ // Low index 0 is a special case in ggen.c
+ // so test both 0 and 1.
+ testExpr(b, pae + "[0:" + cni + "]")
+ testExpr(b, pae + "[1:" + cni + "]")
+ testExpr(b, pae + "[" + cni + ":]")
+ testExpr(b, pae + "[" + cni + ":" + cni + "]")
+ }
+ })
+
+ fmt.Fprintln(b, "}")
+ b.Flush()
+}
+
+func forall(choices [][]string, f func([]string)) {
+ x := make([]string, len(choices))
+
+ var recurse func(d int)
+ recurse = func(d int) {
+ if d >= len(choices) {
+ f(x)
+ return
+ }
+ for _, x[d] = range choices[d] {
+ recurse(d+1)
+ }
+ }
+ recurse(0)
+}
