Article: Finding memory bugs in D code with AddressSanitizer

[Walter Bright]

On 12/25/2017 9:03 AM, Johan Engelen wrote:
> I've been writing this article since August, and finally found some time to 
> finish it:
> 
> http://johanengelen.github.io/ldc/2017/12/25/LDC-and-AddressSanitizer.html
> 
> "LDC comes with improved support for Address Sanitizer since the 1.4.0 release. 
> Address Sanitizer (ASan) is a runtime memory write/read checker that helps 
> discover and locate memory access bugs. ASan is part of the official LDC release 
> binaries; to use it you must build with -fsanitize=address. In this article, 
> I’ll explain how to use ASan, what kind of bugs it can find, and what bugs it 
> will be able to find in the (hopefully near) future."

Thanks for the great article! Some suggestions:

1. The gray-on-white text is not very legible.

2. "Although D tries to be a more safe language, the safety measures still 
require developer effort and discipline. And so D code suffers from similar 
memory bugs that plague people in C++."

This comes across as unduly negative. D is a *lot* better than C++ in this 
regard. It doesn't just try to be more safe, it *is* more safe.

3. "A simple example"

This is a contrived example, and implies that normal D code is written like C++ 
code. It isn't, the parameter to foo() would be int[], not int*. The code would 
also be rejected by the compiler when annotated with @safe.

If you want to keep the example, a note of explanation about this would work. 
Because of D's array and ref types, very very little D code needs to manipulate 
pointers.

It would be nice to add a paragraph mentioning things about D that make it a 
more memory safe language.

4. "Future work: detecting stack use after return"

This code should be rejected by the compiler if using -dip1000. It is not, so I 
filed a bug report:

https://issues.dlang.org/show_bug.cgi?id=18128

I don't know if the fault lies with the compiler or with std.algorithm.move, but 
I'd rather use examples that didn't rely on compiler/library bugs.