<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Feb 29, 2016, at 3:18 PM, David Blaikie <<a href="mailto:dblaikie@gmail.com" class="">dblaikie@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">Just in case it interests anyone else, I'm playing around with trying to broaden the MCStreamer API to allow for emission of bytes without copying the contents into a local buffer first (either because you already have a buffer, or the bytes are already present in another file, etc) in <a href="http://reviews.llvm.org/D17694" class="">http://reviews.llvm.org/D17694</a> . In theory there's some overlap with lld here (no doubt it already does this sort of thing, but not in a way, I assume, we could reuse from other tools at the moment) and my motivation, llvm-dwp, looks very much like "linking with a few extra steps".<br class=""><br class="">But to check that these changes might be more generally applicable, I thought I'd solicit data from anyone building tools that might be memory constrained as well.<br class=""><br class="">First that comes to mind (Eric suggested/mentioned) is llvm-dsymutil.<br class=""><br class="">Adrian/Fred - do you guys ever have trouble with memory usage of llvm-dsymutil? Do you have an example you could provide that has high memory usage, so I could see if any simple changes based on my prototype MC changes would help. <br class=""></div></div></blockquote><div><br class=""></div><div>Since dsymutil processes object files one after another, memory usage wasn’t really a problem so far, but you could try running llvm-dsymutil on bin/clang for a larger example (takes about a minute to finish).</div><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><br class="">A quick glance at dsymutil's code indicates it might benefit slightly, at least - in the string table emission, for example (it looks very similar to string table emission in dwp - just being able to reference the strings in the StringMap rather than copying them into MCStreamer could help (also I found using a DenseMap<StringRef to the memory mapped input helped as well - but that's a change you can make locally without any MCStreamer improvements) - other parts might be trickier, and consist of parts of referencable data (like the line table header) and parts that are not referencable (like their contents) - my prototype could be extended to handle that)<br class=""></div>
</div></blockquote></div><br class=""><div class="">-- adrian</div></body></html>