llvm

The clang 3.0 online demo page http://llvm.org/demo/index.cgi provides an option to output LLVM C++ API code" representing the LLVM-IR for the input program. Is "produce LLVM C++ API code" output a clang option (and if so, what is it)? Or is it an llvm tool option (which one)? Is it possible to do the same thing but from LLVM-IR input? Basically I'd like to see the proper llvm c++ api calls needed to produce a particular given llvm-ir sequence. I'd like to learn backwards by example rather than forwards from the documentation. Manual pages and --help and --help-hidden for clang, llvm-as and

I'm trying to understand the output of the gcov tool. Running it with no options makes sense, but I'm wanting to try and understand the branch coverage options. Unfortunately it's hard to make sense of what the branches do and why they aren't taken. Below is the output for a method (compile using the latest LLVM/Clang build). function -[TestCoverageAppDelegate loopThroughArray:] called 5 returned 100% blocks executed 88% 5: 30:- (NSInteger)loopThroughArray:(NSArray *)array { 5: 31: NSInteger i = 0; 22: 32: for (NSString *string in array) { branch 0 taken 0 branch 1 taken 7 -: 33: 22: 34: }

作者： snsn1984 第一步：复习 第三天的时候，我们学习了LLVM的编程指引。在开始第四天的学习之前，需要复习之前学习过的两篇文档： LLVM IR的文档（ http://llvm.org/docs/LangRef.html ） 编程指引文档 （ http://llvm.org/docs/ProgrammersManual.html ） 这两篇文档是LLVM的重中之重，希望学习的时候认真一点，能掌握这些文档的核心。 第二步：阅读文档 Write an LLVM pass http://llvm.org/docs/WritingAnLLVMPass.html 在阅读的过程中，文档中提到的例子要自己认真运行一下，并且对提到的实际代码，要认真的阅读。 对Pass的简要介绍，可参加我之前的一个博文： http://blog.csdn.net/snsn1984/article/details/8160696 同时，还有一个对Pass例子的分析： http://blog.csdn.net/snsn1984/article/details/8568828 第三步：自己根据HelloWorld的例子，写一个输出一个函数中所有的BasicBlock的name的Pass. 这个Pass是FunctionPass的子类，通过自己实现runOnFunction

Context: I have several loops in an Objective-C library I am writing which deal with processing large text arrays. I can see that right now it is running in a single threaded manner. I understand that LLVM is now capable of auto-vectorising loops, as described at Apple's session at WWDC. It is however very cautious in the way it does it, one reason being the possibility of variables being modified due to CPU pipelining. My question: how can I see where LLVM has vectorised my code, and, more usefully, how can I receive debug messages that explain why it can't vectorise my code? I'm sure if it

Edit/Update/Note: Just let clang use libstdc++. Has been working really well for me so far. =============================== In the past I have been able to succeed by doing something with cmake , but just now I discovered a buildit script inside the lib directory of the http://llvm.org/svn/llvm-project/libcxx/trunk project tree. This buildit script appears to not make use of libsupc++ which is what the cmake approach that I took earlier used. For instance, this guide shows one cmake incantation to produce a makefile for libc++ , which will be able to take care of compiling and installation. My

I am running on an RHEL 6.x box, which of course has GCC 4.4 installed. I wish to have LLVM running on this machine. In order to do so, I must compile it from source. In order to do that , I need a more modern version of GCC. So, following the instructions , I have built GCC 4.8.2: [snip] % $PWD/../gcc-4.8.2/configure --prefix=$HOME/toolchains --enable-languages=c,c++ % make -j$(nproc) % make install I'm logged in as root, so $HOME/toolchains resolves to /root/toolchains . After satisfying prerequisites for LLVM, I'm ready to configure and build LLVM. root@dev06 /root/llvm-build # ~/llvm