On Wed, Mar 16, 2016 at 3:36 PM, jps...@gmail.com <jps...@gmail.com> wrote:
> > > On Wed, Mar 16, 2016 at 5:55 PM, David Blaikie <dblai...@gmail.com> wrote: > >> >> >> On Wed, Mar 16, 2016 at 2:12 PM, jps...@gmail.com <jps...@gmail.com> >> wrote: >> >>> David and all, a couple more questions. I stumbled upon >>> http://llvm.org/docs/Packaging.html and see a few other options. For a >>> typical clang build where I am not hacking on clang, but I do want good >>> error messages for debugging my programs, >>> >> >> Define "my programs" - are you using LLVM as a library? If so, you >> probably want a with-asserts build for development so you get better >> failures when you use LLVM incorrectly. If you're just using Clang as a >> normal compiler - a build without assertions should be just fine. If you >> hit a crash in the compiler you can still file it, and we'll run in with an >> assertions-enabled build to investigate further, generally. >> > > Just using clang (and clang tools) -- not using LLVM as a library. So, > running without assertions seems right for my needs. > > >> >> >>> which options are recommended [1]? It seems like I should use >>> --disable-assertions, but I'm not sure about enable-debug-symbols and >>> enable-optimized (which seem at odds with each other?). >>> >> >> If you're using LLVM as a library, but not expecting to be able to fix >> any bugs in it yourself, probably optimized with assertiotns and without >> debug info should be fine. >> >> If you're just using clang as a compiler, release (optimized), no >> assertions, no debug info. >> >> > > It seems that just enabling -DCMAKE_BUILD_TYPE=Release is not sufficient > to turn off assertions as I tried that and when I run clang-tidy --version > it says " LLVM version 3.9.0svn; Optimized build with assertions." So, I'm > going to try --disable-assertions --enable-optimized --disable-debug-symbols > (or the environment variable equivalents). > > That seem right to you? > Yeah, sounds about right. > It's still confusing to me that there's no CMAKE_BUILD_TYPE that enables > these sorts of options as a bundle, but I guess that's what I get from > compiling from source. > Yeah - not sure what the right recipe is for building things the same as the official releases. No doubt it's written down somewhere... > > Thanks > Jim > > > > >> [1] >> >>> --disable-assertions--enable-debug-symbols--enable-optimized >>> [2] >>> >>> $ clang --version >>> >>> clang version 3.9.0 (trunk 263648) >>> >>> Target: x86_64-apple-darwin15.0.0 >>> >>> Thread model: posix >>> >>> InstalledDir: /Users/jim/toolchains/llvm/bin >>> >>> On Wed, Mar 16, 2016 at 2:05 PM, jps...@gmail.com <jps...@gmail.com> >>> wrote: >>> >>>> Got it -- thanks! >>>> >>>> >>>> On Wednesday, March 16, 2016, David Blaikie <dblai...@gmail.com> wrote: >>>> >>>>> >>>>> >>>>> On Wed, Mar 16, 2016 at 7:25 AM, jps...@gmail.com via cfe-users < >>>>> cfe-users@lists.llvm.org> wrote: >>>>> >>>>>> Hi, I recently installed "Release" clang (svn r263305) from source on >>>>>> my OSX machine, and it's compiling a 20 file C++ program about 50% slower >>>>>> than the natively installed clang 3.7 (that came with xcode, I believe, >>>>>> although I don't use xcode). I currently have both sets of tools >>>>>> installed >>>>>> and am able to switch back and forth and verify using time that clang 3.7 >>>>>> takes about 30 seconds and clang 3.9 takes about 45 seconds, on average >>>>>> (all flags, settings, etc. are the same for both). I did build with >>>>>> "Release" as the build type, although I also did set >>>>>> DLLVM_ENABLE_ASSERTIONS=ON (could this be the problem?). >>>>>> >>>>> >>>>> Yes, the build system should print a warning telling you that an >>>>> assertions enabled build can be up to ten times slower. Performance >>>>> comparisons/measurements of an assertions enabled compiler aren't >>>>> something >>>>> we really do/tune for. >>>>> >>>>> >>>>>> More details below. Please let me know if you have any ideas about >>>>>> why this newer clang would be noticable slower. >>>>>> >>>>>> Generally, I'm just trying to use clang as a user, not a clang >>>>>> developer, so if you have general recommendations for how to configure >>>>>> this, please let me know. >>>>>> >>>>>> Thank you, >>>>>> Jim >>>>>> >>>>>> How I configured and installed: >>>>>> >>>>>> cmake -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Release >>>>>> -DLLVM_ENABLE_ASSERTIONS=ON ../llvm >>>>>> make >>>>>> cmake -DCMAKE_INSTALL_PREFIX=$CLANG_PREFIX -P cmake_install.cmake >>>>>> >>>>>> >>>>>> Here are some specifics: >>>>>> >>>>>> $ uname -a >>>>>> Darwin localhost 15.0.0 Darwin Kernel Version 15.0.0: Wed Aug 26 >>>>>> 16:57:32 PDT 2015; root:xnu-3247.1.106~1/RELEASE_X86_64 x86_64 >>>>>> >>>>>> $ clang --version >>>>>> clang version 3.9.0 (trunk 263305) >>>>>> Target: x86_64-apple-darwin15.0.0 >>>>>> Thread model: posix >>>>>> InstalledDir: /Users/jim/toolchains/llvm/bin >>>>>> >>>>>> _______________________________________________ >>>>>> cfe-users mailing list >>>>>> cfe-users@lists.llvm.org >>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-users >>>>>> >>>>>> >>>>> >>> >> >
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