4 ms·

Since, according to Chandler Carruth, the aim for Clang is to not do optimizations based on undefined behaviour without a corresponding instrument in ubsan[0],

by nly 11y ago

Since, according to Chandler Carruth, the aim for Clang is to not do optimizations based on undefined behaviour without a corresponding instrument in ubsan[0], I don't see much traction on this well-defined/boring C effort. You know, in my experience, things would be great if people actually turned on warnings. I write all my new code with -Weverything with a few noise categories turned off. Everybody should build code at this level from day 1. [0] http://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html http://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html

regehr 11y ago
For new code and for actively maintained old code you are perfectly correct. But there is a huge amount of C code we still rely on that isn't getting enough attention and I don't want that getting broken either.
regehr 11y ago
Also we're all waiting for the strict aliasing checker.
dietrichepp 11y ago
At work, we migrated a small codebase this year to VS2008. It was "painful". This week I put it through asan and found five buffer overflows or similar with about a half hour of work, but the thing still spits out a hundred warnings or so when you compile, and that's with default settings. This project is about 1% of the code, by line count, that my team is responsible for. At home, I turn on -Wall -Wextra for starters, enable about a dozen more for good measure, with -Werror as the pièce de réisistance.
btrask 11y ago
The problem is UBSan is still kind of a pain to use. Just turn all of these optimizations directly into warnings and the problem would be solved--if you want to optimize them, the warnings will let you do it yourself.
npsimons 11y ago
> Everybody should build code at this level from day 1. On the project I run, the CI will reject your code in CR if it doesn't compile under two different compilers with all but a handful of warnings turned on as errors, runs and passes tests, and passes various linters, including a check for undocumented types, variables, parameters and return values. IMNSHO, every project should be like this. Once it's setup, it's a breeze and doesn't impede development speed at all.

by nly 11y ago

regehr 11y ago

For new code and for actively maintained old code you are perfectly correct. But there is a huge amount of C code we still rely on that isn't getting enough attention and I don't want that getting broken either.

regehr 11y ago

Also we're all waiting for the strict aliasing checker.

dietrichepp 11y ago

At work, we migrated a small codebase this year to VS2008. It was "painful". This week I put it through asan and found five buffer overflows or similar with about a half hour of work, but the thing still spits out a hundred warnings or so when you compile, and that's with default settings. This project is about 1% of the code, by line count, that my team is responsible for. At home, I turn on -Wall -Wextra for starters, enable about a dozen more for good measure, with -Werror as the pièce de réisistance.

btrask 11y ago

The problem is UBSan is still kind of a pain to use. Just turn all of these optimizations directly into warnings and the problem would be solved--if you want to optimize them, the warnings will let you do it yourself.

npsimons 11y ago

> Everybody should build code at this level from day 1. On the project I run, the CI will reject your code in CR if it doesn't compile under two different compilers with all but a handful of warnings turned on as errors, runs and passes tests, and passes various linters, including a check for undocumented types, variables, parameters and return values. IMNSHO, every project should be like this. Once it's setup, it's a breeze and doesn't impede development speed at all.