[Issue 4835] DMD should warn about integer overflow in computed constant
https://issues.dlang.org/show_bug.cgi?id=4835 Iain Buclaw changed: What|Removed |Added Priority|P2 |P4 --
[Issue 4835] DMD should warn about integer overflow in computed constant
https://issues.dlang.org/show_bug.cgi?id=4835 Andrei Alexandrescu changed: What|Removed |Added Version|D1 & D2 |D2 --
[Issue 4835] DMD should warn about integer overflow in computed constant
https://issues.dlang.org/show_bug.cgi?id=4835 Leandro Lucarella changed: What|Removed |Added Keywords||industry CC||leandro.lucarella@sociomant ||ic.com Version|D2 |D1 & D2 --
[Issue 4835] DMD should warn about integer overflow in computed constant
https://issues.dlang.org/show_bug.cgi?id=4835 bearophile_h...@eml.cc changed: What|Removed |Added CC||pub...@dicebot.lv --- Comment #17 from bearophile_h...@eml.cc --- *** Issue 13785 has been marked as a duplicate of this issue. *** --
[Issue 4835] DMD should warn about integer overflow in computed constant
https://issues.dlang.org/show_bug.cgi?id=4835 hst...@quickfur.ath.cx changed: What|Removed |Added Keywords||pull --
[Issue 4835] DMD should warn about integer overflow in computed constant
http://d.puremagic.com/issues/show_bug.cgi?id=4835 --- Comment #16 from Walter Bright 2013-03-28 00:39:03 PDT --- (In reply to comment #15) > Walter, what do you mean, screw? Is that a limitation of the dmd backend, or > are you arguing that it is problematic in general? LLVM implements it, as > bearophile points out... Consider all the addressing modes used - they are all adds, with no overflow checks. Secondly, they all rely on wraparound (overflow) arithmetic, after all, that is how subtraction is done. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 4835] DMD should warn about integer overflow in computed constant
http://d.puremagic.com/issues/show_bug.cgi?id=4835 --- Comment #15 from Lu�s Marques 2013-03-27 09:00:14 PDT --- (In reply to comment #13) > Because it'll screw things up right and left, for example, address > calculations. Walter, what do you mean, screw? Is that a limitation of the dmd backend, or are you arguing that it is problematic in general? LLVM implements it, as bearophile points out... -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 4835] DMD should warn about integer overflow in computed constant
http://d.puremagic.com/issues/show_bug.cgi?id=4835 --- Comment #14 from bearophile_h...@eml.cc 2013-03-27 04:00:40 PDT --- (In reply to comment #11) > While I disagree with bearophile about doing such checks at runtime, due to > the > performance cost, A feature of LLVM 3.3, it seems those costs are not too much large for C language: http://clang.llvm.org/docs/UsersManual.html#controlling-code-generation See: -fsanitize=signed-integer-overflow -fsanitize=integer More info: http://embed.cs.utah.edu/ioc/ -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 4835] DMD should warn about integer overflow in computed constant
http://d.puremagic.com/issues/show_bug.cgi?id=4835 --- Comment #13 from Walter Bright 2013-03-27 02:38:18 PDT --- Because it'll screw things up right and left, for example, address calculations. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 4835] DMD should warn about integer overflow in computed constant
http://d.puremagic.com/issues/show_bug.cgi?id=4835 --- Comment #12 from Lu�s Marques 2013-03-26 22:46:13 PDT --- (In reply to comment #11) > While I disagree with bearophile about doing such checks at runtime, due to > the > performance cost, doing them at compile time is a whole 'nother story. Why don't you make the runtime over/underflow checks opt-in? (compiler option). There's a 0 performance cost that way, both for debug and release, by default, so no performance excuse. Then we can always discuss it later if it should be opt-out for the debug builds. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 4835] DMD should warn about integer overflow in computed constant
http://d.puremagic.com/issues/show_bug.cgi?id=4835 --- Comment #11 from Walter Bright 2013-03-26 22:36:40 PDT --- While I disagree with bearophile about doing such checks at runtime, due to the performance cost, doing them at compile time is a whole 'nother story. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 4835] DMD should warn about integer overflow in computed constant
http://d.puremagic.com/issues/show_bug.cgi?id=4835 --- Comment #10 from Lu�s Marques 2013-03-26 20:04:13 PDT --- (In reply to comment #9) > (In reply to comment #8) > > https://github.com/D-Programming-Language/dmd/pull/1803 > > An error, even :-) So the issue name should be updated. > > Thank you Walter. Let's see how this patch goes. I hope the feedback I provided with being bitten by this corner case helped nudge this issue to the limelight, that way I can feel slightly important ;-). Thanks for addressing it so quickly Walter. (Also, isn't it strange that this was addressed quicker than in Java, which should have a larger support community, where the issue remains? Go D! (At least it remains with javac 1.6.0_43)) -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 4835] DMD should warn about integer overflow in computed constant
http://d.puremagic.com/issues/show_bug.cgi?id=4835 --- Comment #9 from bearophile_h...@eml.cc 2013-03-26 19:45:01 PDT --- (In reply to comment #8) > https://github.com/D-Programming-Language/dmd/pull/1803 An error, even :-) So the issue name should be updated. Thank you Walter. Let's see how this patch goes. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 4835] DMD should warn about integer overflow in computed constant
http://d.puremagic.com/issues/show_bug.cgi?id=4835 --- Comment #8 from Walter Bright 2013-03-26 19:06:55 PDT --- https://github.com/D-Programming-Language/dmd/pull/1803 -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 4835] DMD should warn about integer overflow in computed constant
http://d.puremagic.com/issues/show_bug.cgi?id=4835
--- Comment #7 from bearophile_h...@eml.cc 2013-03-26 15:13:56 PDT ---
(In reply to comment #6)
> uint foo() {
> uint x = 1 << 40;
> return 1 << 90;
> }
>
> gives:
>
> foo2.d(3): Error: shift by 40 is outside the range 0..31
> foo2.d(4): Error: shift by 90 is outside the range 0..31
I was aware of that. I have added the 1<<90 example to show the peculiar error
message given by Go, that contains 1237940039285380274899124224, that is larger
than a ulong.
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[Issue 4835] DMD should warn about integer overflow in computed constant
http://d.puremagic.com/issues/show_bug.cgi?id=4835
Walter Bright changed:
What|Removed |Added
CC||bugzi...@digitalmars.com
--- Comment #6 from Walter Bright 2013-03-26
13:14:08 PDT ---
uint foo() {
uint x = 1 << 40;
return 1 << 90;
}
gives:
foo2.d(3): Error: shift by 40 is outside the range 0..31
foo2.d(4): Error: shift by 90 is outside the range 0..31
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[Issue 4835] DMD should warn about integer overflow in computed constant
http://d.puremagic.com/issues/show_bug.cgi?id=4835 Lu�s Marques changed: What|Removed |Added CC||luismarq...@gmail.com --- Comment #5 from Lu�s Marques 2013-03-26 11:50:04 PDT --- (In reply to comment #4) For completeness, it also does not have a problem (like in your example) where the initializer of the 64-bit variable is initialized with (what is not obvious) a folded and truncated 32-bit int: var x uint64 = 4 * 1024 * 1024 * 1024; // x is now 4294967296, not 0. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 4835] DMD should warn about integer overflow in computed constant
http://d.puremagic.com/issues/show_bug.cgi?id=4835
--- Comment #3 from bearophile_h...@eml.cc 2013-03-26 11:27:23 PDT ---
An example in Go language:
package main
func main() {
var x uint32 = 1 << 40
var y = 1024 * 1024 * 1024 * 6
}
The Go compiler gives the errors:
test.go:3: constant 1099511627776 overflows uint32
test.go:4: constant 6442450944 overflows int
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[Issue 4835] DMD should warn about integer overflow in computed constant
http://d.puremagic.com/issues/show_bug.cgi?id=4835
--- Comment #4 from bearophile_h...@eml.cc 2013-03-26 11:29:45 PDT ---
Another example in Go:
package main
func main() {
var x uint64 = 1 << 90
}
The Go compiler gives the error:
test.go:3: constant 1237940039285380274899124224 overflows uint64
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[Issue 4835] DMD should warn about integer overflow in computed constant
http://d.puremagic.com/issues/show_bug.cgi?id=4835 Brad Roberts changed: What|Removed |Added Platform|x86_64 |x86 --- Comment #2 from Brad Roberts 2011-02-06 15:38:57 PST --- Mass migration of bugs marked as x86-64 to just x86. The platform run on isn't what's relevant, it's if the app is a 32 or 64 bit app. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 4835] DMD should warn about integer overflow in computed constant
http://d.puremagic.com/issues/show_bug.cgi?id=4835
bearophile_h...@eml.cc changed:
What|Removed |Added
CC||bearophile_h...@eml.cc
--- Comment #1 from bearophile_h...@eml.cc 2010-09-07 12:39:13 PDT ---
I'm asking for overflow detection for years (both at compile-time and
run-time).
Again here the C language is better than the D language:
// C code
#include "stdio.h"
int main() {
long long x = 1024 * 1024 * 1024 * 6;
printf("%lld\n", x);
return 0;
}
GCC 4.3.4 gives:
prog.c: In function ‘main’:
prog.c:3: warning: integer overflow in expression
D compiler is not _practical_ enough yet.
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