zturner added inline comments.
================ Comment at: source/Core/Log.cpp:78 + char *text; + vasprintf(&text, format, args); + message << text; ---------------- dancol wrote: > I usually implement printf-into-std::string by using `vsnprintf` to figure > out how many characters we generate, using `std::string::resize` to create a > buffer of that many characters (unfortunately, zero-filling them), then > `vsnprintf` directly into that buffer. This way, you only need one allocation. > > The currant approach involves at least three allocations: first, the string > generated by `vasprintf`. Second, the internal `stringstream` buffer. Third, > the copy of the buffer that `std::stringstream::str` generates. > > It's more expensive that it needs to be. To be fair, we should really be deleting these methods long term, and using `formatv`. This way you often end up with 0 allocations (for short messages), and on top of that, only one underlying format call (as opposed to wasting time calling `vasprintf` twice here). https://reviews.llvm.org/D27459 _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
