similar to: Tablegen ridiculously slow when compiling for Debug

Hi Florian, Ok, I ran this: cmake -S LLVM -DCMAKE_INSTALL_PREFIX=INSTALL -DLLVM_OPTIMIZED_TABLEGEN=On -G Xcode Compiled it again from clean, and the situation is worse than before. Incremental builds take an incredible amount of time stuck in running Tablegen scripts for all targets. Now this happens both in Release and Debug configurations. Just before this, at least Release compiled fine, but

Hi Praveen, Thanks for the tip, but Xcode seems to spend all the time running tablegen "custom shell scripts", one by one at a time, not linking. Linking is actually very fast, possibly less than a second. The “scripts” that take longer are “AArch64CommonTableGen" and “AMDGPUCommonTableGen”. As said this is on LLVM 9.0. However, on LLVM 7.0.1, the same process takes just 5-6

Hi Praveen, Please, can you elaborate on this?. What do do mean by “building as shared objects”. Thanks, John > On 30 Jun 2019, at 07:32, Praveen Velliengiri <praveenvelliengiri at gmail.com> wrote: > > Maybe try building llvm as a shared objects.. > > On Jun 30, 2019 1:30 AM, "Joan Lluch via llvm-dev" <llvm-dev at lists.llvm.org <mailto:llvm-dev at

This is also the case with the Visual Studio generators. Custom commands in a single cmake file essentially get written out line by line into a single batch file that gets processed as a custom build step. In the VS case this means that it can, for example, run X86 and Aarch64 tablegen steps in parallel with each other but all of the individual X86 invocations get processed serially. I can well

Hey Joan, When looking for build support it is really useful to include a bunch of information about your build up front. Knowing that you are on macOS, and using the Xcode generator are really useful. On macOS, BUILD_SHARED_LIBS won’t really help much because the default linker (ld64) is pretty good. Using an IDE generator and setting LLVM_USE_OPTIMIZED_TABLEGEN will kill your release builds.

If someone can manage it, it wouldn't be a bad thing - obviously open up more parallelism (I don't know how much of LLVM can be built before you hit everything that needs tblgen run - I guess libSupport and some other bits) On Mon, Jul 1, 2019 at 12:54 PM Zakharin, Vyacheslav P via llvm-dev < llvm-dev at lists.llvm.org> wrote: > [resending to the whole list] > > > >

Much of this has been discussed (over many, many years) on https://bugs.llvm.org/show_bug.cgi?id=28222 Some of the issues that were identified included: 1 - Poor tablegen dependency handling leading to unexpected rebuilds. 2 - Debug STL iterator checks taking an insane amount of time (might be MSVC specific). 3 - Lack of parallelization of custom commands (XCode and VS builds) - VS at least

FWIW, tablegen does not update timestamps for .inc files, if their contents is unchanged, so if you somehow affect a .td file's timestamp (without changing its contents) it will trigger rebuild of the corresponding .inc file with all subsequent incremental make builds. At the same time, this will not trigger rebuilding any targets dependent on this .inc file, since it is not modified. From

I’m not saying you can’t use Xcode, I’m just saying that instead of *building* in Xcode, just type “ninja” on the command line to do your build and then use Xcode as you normally would. I don’t think it’s the case that LLVM does not intend to support Xcode, just that its a community driven project, so unless someone is sufficiently motivated to fix whatever this problem is, it might stay this way

I don’t personally develop on Mac (i use Windows), but I have an analogous setup there where i use ninja to build and Visual Studio for editing, debugging, etc. What i do, and I assume it will be the same or very similar for Xcode, is to run cmake twice, once with Ninja, and once with VS (Xcode for you), from separate directories. I build with the ninja one (“ninja clang” on command line), and I

Hey Joan, Take a look at this patch, and see if it resolves your issue: https://reviews.llvm.org/D64300 <https://reviews.llvm.org/D64300> Thanks, -Chris > On Jul 7, 2019, at 3:54 PM, Chris Bieneman via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > Hey Joan, > > I looked into the Xcode build issue that you're experiencing, and it relates to a limitation in

Try using ninja generator, most people do not use Xcode for building, so since it lesser-used, it also lesser tested. Note that it’s perfectly possible to use Xcode for code browsing, debugging, editing while using ninja for building, which is what I think most people do On Sun, Jul 7, 2019 at 4:20 AM Joan Lluch via llvm-dev < llvm-dev at lists.llvm.org> wrote: > I also filled a bug

I understand that a difference between ninja and xcode is they use a different way to determine code dependencies. So to my understanding xcode needs dependencies to be properly created whereas ninja just doesn’t care. Maybe this is why ninja is able to find what it needs for the compilation to succeed, but not xcode. So I have now looked at the CMakeLists.txt files and found that all the missing

Hi Nelson, Thanks for your reply. The “build/Debug/lib” and "build/Release/lib” directories is where all the libraries go. Similarly, the executables go to “build/Debug/bin” and “build/Release/bin” before they are moved to the install directory. This is expected and normal. However, the problem is that a small number of libraries (exactly 20 in total) are not created at all for the LLVM

Hi Eli, Thanks again for your reply. I am unsure about implementing the getCrossCopyRegClass for my target. My target does not support or allow moves to and from the SR. The SR exists because it has implicit involvement in some instructions, but it is opaque to the assembler and to the user as a register. I mean, there are no instructions to directly move or read it, or even access it directly.

Hi all In order to get ready for the upcoming final 9.0 release code I have now switched to the 'release/9.x' branch that I pulled from github. Unfortunately, after running cmake in the usual way, I found that many xcode schemes are missing on the resulting project. Particularly, I added -DLLVM_ENABLE_PROJECTS=clang to the terminal command line. The logs correctly state that ‘clang

Hi Tim, I appreciate your reply, but I can’t still find any relation with “LargeArrayMinWidth” and x86 target. This variable is only in the TargetInfo.cpp and TargetInfo.h files and it’s not even in any x86 related file. I think there should be something else that causes my issue. I have my backend very advanced and already producing good assembly code, but this supposedly simple thing has got me

Sorry Zach, my apologies. I understood now what you mean. I tried and it works!. But now I found that LLVM_DEBUG statements and other output to the console doesn’t show. How do I get that back?. Thanks John > On 4 Nov 2019, at 22:26, Zachary Turner <zturner at roblox.com> wrote: > > You hit Reply on my email but then addressed David. So I want to make sure you saw my

Hi Eli, Thank you very much for your response. In fact, I had already tried the X86 approach before, i.e explicitly using the status register. This is the approach that appeals more to me. I left it parked because it also produced some problems (but I left it commented out). So I have now re-lived the code, and it works fine in most cases, but there’s a particular case that causes LLVM to stop

I had already adjusted MaxStoresPerMemcpy to my preferred value, and this works great but for the cases where load/stores are used on non-size aligned structs the odd behaviour still happens. For my 3-char, 3-byte struct test, the memcpy replacement appears to consist on a single byte load and store of the last char (this is correct), followed by a 16 bit move of the first two chars, this is also