4 ms·

I'd have loved to see references to actual GCC bug reports. Did I miss those in the article? Thankfully, the world is changing. You have languages where vari

by 0xmohit 10y ago

I'd have loved to see references to actual GCC bug reports. Did I miss those in the article? Thankfully, the world is changing. You have languages where variables are immutable by default or can be declared so that would prevent issues as http://www.viva64.com/en/d/0108/ http://www.viva64.com/en/d/0108/ Maybe gcc should do better for static analysis of a program. Expressions like `a && a` or `a == 1 || a != 2` should be caught easily.

i_have_to_speak 10y ago
If you're suggesting that discovery of a bug in a popular open source project holds the discoverer up to a moral responsibility of reporting it -- well then, maybe you are guilty too!
- rcthompson 10y ago
  There's no obligation to report a bug you've found, of course. But if you've taken the time to write a blog post about it, one would hope you've also taken the time to directly notify the software authors as well.
  - i_have_to_speak 10y ago
    But if you hadn't taken as much time -- say you've only come across a well written blog post clearly describing the bug -- would you report it?
- 0xmohit 10y ago
  Given (1) the blog post, (2) the author posted the blog link on HN, I assumed that the bugs would have reported upstream. If it were a blog describing a 0-day vulnerability in a given software, I wouldn't have assumed that it would have been reported.
AndreyKarpov 10y ago
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77421 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77421
- 0xmohit 10y ago
  Thanks. That provides pointers to the specific issues: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71345 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71345 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77430 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77430 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64767 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64767 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77444 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77444 -- And fixes have also started coming in: https://gcc.gnu.org/viewcvs?rev=239959&root=gcc&view=rev https://gcc.gnu.org/viewcvs?rev=239959&root=gcc&view=rev Kudos for investigating and reporting the issues.
mtkd 10y ago
a == 1 || a != 2 needs a warning but it's not necessarily a bug sometimes I may keep overlapping expressions in a statement to remind me of the triggers I'm looking for at this point - and would likely use some meaningful constant names for the 1 and 2 statements aren't just logic - they're often documentation too - especially on code you might not look at again for months I used to have many arguments with a professor whose code I was working on - he would factor out everything in an expression - removing all the parentheses and rely on operator precedence - it was often impenetrable (for me) - so I'd unpack it, wrap parentheses everywhere, change single letter vars to meaningful ones etc. - he'd be in my office an hour later ranting
- 0xmohit 10y ago
  > a == 1 || a != 2 needs a warning Yes, it needs a warning because it's kind of obvious that there is something amiss about this expression. Only the author could tell what was specifically wrong.
- raverbashing 10y ago
  Yes I would advocate for the maintenance of both expressions if the comparison is tricky If this is a hot path that must absolutely be optimized then a comment explaining the conditions is needed And of course, the != 2 question might change (either because of a bug or logic change) but the == 1 might still be valid, however, if you took the first one your change will break the code

by 0xmohit 10y ago

i_have_to_speak 10y ago

If you're suggesting that discovery of a bug in a popular open source project holds the discoverer up to a moral responsibility of reporting it -- well then, maybe you are guilty too!

rcthompson 10y ago
There's no obligation to report a bug you've found, of course. But if you've taken the time to write a blog post about it, one would hope you've also taken the time to directly notify the software authors as well.
- i_have_to_speak 10y ago
  But if you hadn't taken as much time -- say you've only come across a well written blog post clearly describing the bug -- would you report it?
0xmohit 10y ago
Given (1) the blog post, (2) the author posted the blog link on HN, I assumed that the bugs would have reported upstream. If it were a blog describing a 0-day vulnerability in a given software, I wouldn't have assumed that it would have been reported.

AndreyKarpov 10y ago

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77421 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77421

0xmohit 10y ago
Thanks. That provides pointers to the specific issues: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71345 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71345 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77430 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77430 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64767 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64767 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77444 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77444 -- And fixes have also started coming in: https://gcc.gnu.org/viewcvs?rev=239959&root=gcc&view=rev https://gcc.gnu.org/viewcvs?rev=239959&root=gcc&view=rev Kudos for investigating and reporting the issues.

mtkd 10y ago

a == 1 || a != 2 needs a warning but it's not necessarily a bug sometimes I may keep overlapping expressions in a statement to remind me of the triggers I'm looking for at this point - and would likely use some meaningful constant names for the 1 and 2 statements aren't just logic - they're often documentation too - especially on code you might not look at again for months I used to have many arguments with a professor whose code I was working on - he would factor out everything in an expression - removing all the parentheses and rely on operator precedence - it was often impenetrable (for me) - so I'd unpack it, wrap parentheses everywhere, change single letter vars to meaningful ones etc. - he'd be in my office an hour later ranting

0xmohit 10y ago
> a == 1 || a != 2 needs a warning Yes, it needs a warning because it's kind of obvious that there is something amiss about this expression. Only the author could tell what was specifically wrong.
raverbashing 10y ago
Yes I would advocate for the maintenance of both expressions if the comparison is tricky If this is a hot path that must absolutely be optimized then a comment explaining the conditions is needed And of course, the != 2 question might change (either because of a bug or logic change) but the == 1 might still be valid, however, if you took the first one your change will break the code