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cmd/gc: Error out on division by constant zero.

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Fixes #4264.

R=cldorian, rsc
CC=golang-dev
https://golang.org/cl/6845113
This commit is contained in:
Daniel Morsing 2013-01-30 20:21:08 +01:00
parent 6563d8623d
commit ba05a43608
4 changed files with 50 additions and 3 deletions
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7
src/cmd/gc/typecheck.c
View file

@ -640,6 +640,13 @@ reswitch:
n->op = OCMPIFACE;
}
}
if((op == ODIV || op == OMOD) && isconst(r, CTINT))
if(mpcmpfixc(r->val.u.xval, 0) == 0) {
yyerror("division by zero");
goto error;
}
n->type = t;
goto ret;

25
test/64bit.go
View file

@ -594,6 +594,19 @@ const binaryConstR = "func test%vBinaryR%v(a, add, sub, mul, div, mod, and, or,
"}\n" +
"\n"
const binaryConstR0 = "func test%vBinaryR%v(a, add, sub, mul, div, mod, and, or, xor, andnot %v, dodiv bool) {\n" +
" const b %v = %v;\n" +
" const typ = `%s`;\n" +
" if n, op, want := a + b, `+`, add; n != want { ok=false; println(typ, `var`, a, op, `const`, b, `=`, n, `should be`, want); }\n" +
" if n, op, want := a - b, `-`, sub; n != want { ok=false; println(typ, `var`, a, op, `const`, b, `=`, n, `should be`, want); }\n" +
" if n, op, want := a * b, `*`, mul; n != want { ok=false; println(typ, `var`, a, op, `const`, b, `=`, n, `should be`, want); }\n" +
" if n, op, want := a & b, `&`, and; n != want { ok=false; println(typ, `var`, a, op, `const`, b, `=`, n, `should be`, want); }\n" +
" if n, op, want := a | b, `|`, or; n != want { ok=false; println(typ, `var`, a, op, `const`, b, `=`, n, `should be`, want); }\n" +
" if n, op, want := a ^ b, `^`, xor; n != want { ok=false; println(typ, `var`, a, op, `const`, b, `=`, n, `should be`, want); }\n" +
" if n, op, want := a &^ b, `&^`, andnot; n != want { ok=false; println(typ, `var`, a, op, `const`, b, `=`, n, `should be`, want); }\n" +
"}\n" +
"\n"
const shiftConstL = "func test%vShiftL%v(b uint64, left, right %v) {\n" +
" const a %v = %v;\n" +
" const typ = `%s`;\n" +
@ -621,12 +634,20 @@ const shiftConstR = "func test%vShiftR%v(a, left, right %v) {\n" +
func constTests() {
for i, a := range int64Values {
fmt.Fprintf(bout, binaryConstL, "Int64", i, "int64", "int64", a, "int64")
fmt.Fprintf(bout, binaryConstR, "Int64", i, "int64", "int64", a, "int64")
if a.hi == 0 && a.lo == 0 {
fmt.Fprintf(bout, binaryConstR0, "Int64", i, "int64", "int64", a, "int64")
} else {
fmt.Fprintf(bout, binaryConstR, "Int64", i, "int64", "int64", a, "int64")
}
fmt.Fprintf(bout, shiftConstL, "Int64", i, "int64", "int64", a, "int64")
}
for i, a := range uint64Values {
fmt.Fprintf(bout, binaryConstL, "Uint64", i, "uint64", "uint64", a, "uint64")
fmt.Fprintf(bout, binaryConstR, "Uint64", i, "uint64", "uint64", a, "uint64")
if a.hi == 0 && a.lo == 0 {
fmt.Fprintf(bout, binaryConstR0, "Uint64", i, "uint64", "uint64", a, "uint64")
} else {
fmt.Fprintf(bout, binaryConstR, "Uint64", i, "uint64", "uint64", a, "uint64")
}
fmt.Fprintf(bout, shiftConstL, "Uint64", i, "uint64", "uint64", a, "uint64")
}
for i, a := range shiftValues {

2
test/fixedbugs/bug410.go
View file

@ -18,7 +18,7 @@ func zzz () {
for s := range arr {
x := make([]byte, 10)
for i := 0; i < 100 ; i++ {
x[i] ^= k[i-arr[s].num%0]
x[i] ^= k[i-arr[s].num%3]
}
}
}

19
test/fixedbugs/issue4264.go Normal file
View file

@ -0,0 +1,19 @@
// errorcheck
// Copyright 2013 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.
// issue 4264: reject int division by const 0
package main
func main() {
var x int
var y float64
var z complex128
println(x/0) // ERROR "division by zero"
println(y/0)
println(z/0)
}