Has anybody done any performance benchmarking on this? I imagine the changes would be significant based on how hot the vector code is. There are 8 cases I see that would be worth looking into: unsigned and size_t, with and without bounds checking, 32-bit and 64-bit architectures. The performance gains of not doing bounds checking would be worth being extra careful in some cases.
Alex On Wed, Nov 19, 2014 at 4:13 PM, Chris Dumez <cdu...@apple.com> wrote: > If we don’t want to crash on overflow, the callers can use the try*() API > I believe (e.g. tryAppend()). This returns false (and does not resize the > vector) instead of crashing, when we reach the size limit. > > Kr, > -- > Chris Dumez - Apple Inc. > Cupertino, CA > > > > > On Nov 19, 2014, at 2:58 PM, Alexey Proskuryakov <a...@webkit.org> wrote: > > > 19 нояб. 2014 г., в 13:58, Filip Pizlo <fpi...@apple.com> написал(а): > > With Vector though, I don't know how we would differentiate code paths > that need large allocations from ones that don't. Nearly anything that is > exposed as a JS API or deals with external world can hit sizes over 4Gb. > That's not out of reach in most scenarios, not even for resources loaded > from network. > > > Can you provide an example? > > > Yes. XMLHttpRequest::m_binaryResponseBuilder keeps the downloaded data in > a Vector, so any time there is much data, something bad will happen. This > is a case that we should support, and not just crash as we would when we > think that only exploits would try to use as much memory. > > All code that is Blob related also uses Vectors, and of course Blobs can > legitimately be large. > > Crypto code uses Vectors internally for the data. > > These and related uses are all over the place - see also Vectors > in FormDataBuilder, data returned from > FrameLoader::loadResourceSynchronously, plug-in code that loads from > network, SharedBuffer etc. > > - Alexey > > > > _______________________________________________ > webkit-dev mailing list > webkit-dev@lists.webkit.org > https://lists.webkit.org/mailman/listinfo/webkit-dev > > -- Alex Christensen FlexSim Software Products, Inc. *1577 North Technology Way | Building A | Suite 2300 | Orem, Utah 84097* *Voice: 801-224-6914 | Fax: 801-224-6984* *Email:* al...@flexsim.com <k...@flexsim.com> *URL:* www.flexsim.com ---------------------------------------------------------------------------------------- This message may contain confidential information, and is intended only for the use of the individual(s) to whom it is addressed. ----------------------------------------------------------------------------------------
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