similar to: [LLVMdev] How to write a custom LTO pass?

Hi all, I have one analysis pass that I want to perform on call graph SCCs. However, for each function in the SCC, I need function-level analyses, like the dominator tree and the memory dependency analysis. I’ve been told before <http://stackoverflow.com/questions/30059622/using-dominatortreewrapperpass-in-callgraphsccpass> that these were not available from a CallGraphSCCPass. What would

Thanks John. Does this solve the problem of analysis availability though? If I still have to run the function analyses manually, I might as well keep rolling with the CallGraphSCCPass. (I probably should have mentioned that this is what I’m using right now.) Félix > Le 2015-05-19 à 10:12:32, John Criswell <jtcriswel at gmail.com> a écrit : > > On 5/18/15 10:45 PM, Félix Cloutier

So I got very mixed results. With the CallGraphSCCPass, both `addRequired<DominatorTreeWrapperPass>` and `addRequired<MemoryDependenceAnalysis>` fail at runtime. The LLVM core has just two CallGraphSCCPasses and neither uses neither analyses, so it's hard to find a valid example. I transformed the pass into a ModulePass, using scc_iterator as shown in CGPassManager to process

Hi all, I'm trying to generate whole program bitcode files for linux kernel and do interprocedural analysis on kernel. I use llvmlinux to compile kernel with clang and generate a bunch of bitcode files successfully. I need to link all these bitcode files together into a single bitcode file, so that I can run whole program analysis. Should I use libLTO to link all these bitcode files

Thanks John. I guess I will use a ModulePass, so when I am implementing the “runOnModule” function, do I have to loop through all the functions, for each functions all the BasicBlocks and for each BasicBlock all the instructions or given the Module I have to call the CallGraph directly? Is there an example out there? I can’t find anything. Thanks. Simone > On Feb 24, 2015, at 13:29, John

Hi All, I am using clang to compile Mysql source code. Because I want to do some inter-procedural analysis, hopefully, I want to get a .o(bitcode) file(a module) containing all possible function declarations and definitions. Is it possible to do that ? Or you guys have some suggestions? To be clear, like Mysql, there is a mysqld routine, which is a major routine. I want to mysqld.o(which is

I am trying to use CloneFunction to clone every IR function in a program, give the cloned versions a prefix and call the clones from the original functions (redirect the calls). Surprisingly, I see that after the LTO optimizations, the number of machine basic blocks in the two functions differ in some cases. Is this reasonable at all, given that the two functions must be exactly the same in the

Hi, Is there a tutorial on how to get started with writing link-time optimization passes? The documentation at http://www.llvm.org/docs/LinkTimeOptimization.html explains the design of the LTO interface, but does not explain where to start writing code. Would my pass go inside libLTO.a or is it separate from libLTO.a? What I would like to be able to do is traverse through the entire

Are you building llvm-gcc yourself? If so, what version? Xcode releases include an older llvm-gcc and libLTO.dylib, which may not understand bitcode generated by newer self-built compilers. If you are only using llvm-gcc from the Xcode tools release, use the driver from: /Developer/usr/bin/llvm-gcc-4.2 If you are building llvm-gcc yourself, try, in this order: 1) sudo ln -s

Shantonu Sen wrote: > Are you building llvm-gcc yourself? If so, what version? > > Xcode releases include an older llvm-gcc and libLTO.dylib, which may not understand bitcode generated by newer self-built compilers. > Thanks. A bitcode format mismatch was the problem. I'm not sure if the problem stems from the fact that the bitcode was generated for the wrong architecture

Hi all, I would like to create a Pass that given an IR instruction walks starting from that instruction up to the main function to identify all the functions call that have been made to call that instruction. Is it possible? What kind of Pass should I create? Thanks Best, Simone Simone Atzeni simone.at at gmail.com +1 (801) 696-8373

Hi Simon, > From: Simone Atzeni <simone.at at gmail.com> > To: John Criswell <jtcriswel at gmail.com> > Cc: llvmdev at cs.uiuc.edu > Subject: Re: [LLVMdev] Walking thru CallGraph bottom up > Message-ID: <318EBA41-2040-4EFE-B330-5813C817C2A2 at gmail.com> > Content-Type: text/plain; charset="windows-1252" > > I think I got it and the example is

On 2/25/15 10:51 AM, Simone Atzeni wrote: > Thanks John. > > I guess I will use a ModulePass, so when I am implementing the “runOnModule” function, > do I have to loop through all the functions, for each functions all the BasicBlocks and for each BasicBlock all the instructions If you know the Instruction, you can get it's basic block using Instruction::getParent(), and then get

I'm confused. libLTO takes bitcode files as input and creates a native object file as output. Why would libLTO create bitcode as output? If so, you're changing the existing API contract. Or are you creating an out-of-band bitcode file, in which case the linker would never see it. ld doesn't have bitcode support, it has libLTO support, and libLTO is what processes the bitcode.

On 5/6/15 10:19 AM, Kuperstein, Michael M wrote: > > Hello Cristiano, > > I don’t think doFinalization() is really meant to be used this way. > My understanding is that doInitialization() and doFinalization() are designed specifically for modifying the LLVM IR (otherwise, why would a mutable reference to the Function be provided)? If that is not the case, then there is either a

Hello Everyone, Just subscribed to the mailing list. I was wondering how I am going to fetch each functions of a specific source code file (c/c++) using the LLVM framework. For instance, I would like to apply certain passes using llvm-opt on certain functions not the whole file. I would appreciate any hints or idea leading me about the starting point. Regards, -Amir -------------- next part

The documentation you're looking for is: http://llvm.org/docs/WritingAnLLVMPass.html If you're doing an optimization that runs at link-time, you'll probably be writing a ModulePass. You can run any pass at any time over any bitcode file with 'opt -mypass file.bc'. If you want to add it to the list of passes that run when linking via libLTO or llvm-ld, you can add it to

Dear All, I'm trying to use transparent link-time optimization on Mac OS X. I've got Xcode 3.2 installed, and I'm trying to compile code with llvm-gcc -O4. However, I get the following error: gcc -O4 -o dftables .libs/dftables.o ld: warning: in .libs/dftables.o, file is not of required architecture Undefined symbols: "_main", referenced from: start in crt1.10.6.o

Hello, I have created a ModulePass, that now needs LoopInfo information. The ModulePass registration is taken from [1]. I use clang to directly invoke it (This is also a hard requirement, because I need the fancy output of clang warnings/remarks). The problem is, that the dependency to the LoopInfoWrapperPass does not seem to work. The error is: --- snip --- clang-4.0:

Thank you very much John. With an environment variable I need to take some special care, but it looks like the only way to go. On Sun, Mar 30, 2014 at 11:07 AM, John Criswell <criswell at illinois.edu>wrote: > Dear Rahman, > > I think your best option is to modify the code in libLTO so that it runs > your pass when you want it to run. I believe the file you want to modify