similar to: [LLVMdev] source-to-source transformations using LLVM/ Clang

Chandler Carruth <chandlerc at google.com> writes: > The other assumption here is that you want the same file format written by > instrumentation and read back by the compiler. While I think that is an > unsurprising goal, I think it creates quite a few limitations that I'd like to > point out. I think it would be worthwhile to consider the alternative of > having the

Hello, I have a RELENG_6/AMD64 with an AMD64X2 cpu, 1GB of memory, 512MB swap. I remarked that when I run 2 simulation program [1], sometimes, one of them run one or several of its threads [2] very slowly, but sometimes, it doesn't occur. I remarked that is doesn't depend on SMP/UP, ULE/4BSD, i386/AMD64. It seems to occur also with the kernel stress test under the same conditions (all

Hi folk, I'm a newbie to llvm, please first forgive my naive questions. I want to instrument llvm code to do some run-time monitoring work. After reading some of the llvm documentation, it begins clear to me that I can do the instrumentation in a transformation pass. There are several things I want to do in the transformation pass, but I'm not sure whether they are doable and how to do

On 06/06/2014 02:33, Alexey Samsonov wrote: > Hi Alp, > > This warning should be fixed by r210301. However, consider > investigating why the frame size appears to be that large. I believe > we build this code with GCC as well and have seen no complaints > from its implementation of -Wframe-larger-than. CC'ing in llvmdev. Like Chandler said it could just be due to lack of

Hello, I have some questions about removing the instrumented instructions at runtime. Assume I instrument some instructions by using some transformation passes. At runtime, I just need those instrumented instructions at the beginning, and I would like to remove instrumented instructions at runtime to reduce overhead. Does anyone know how to do this by using LLVM? Thanks, Bo -- View

Hi all, I want to test X-ray performance and compare it with other research tools, so I use Clang 7.0.0 to compile and instrument GNU binutils-2.3.1 with the following commands: cd binutils-2.31/ mkdir build cd build/ CC=$local/clang CXX=$local/clang++ CFLAGS=-fxray-instrument CXXFLAGS=-fxray-instrument ../configure --prefix=/home/zhangysh1995/local make Then I extract instrumentation map

On Sun, Jul 9, 2017 at 3:50 PM, Nischai Vinesh <nischai.vinesh at gmail.com> wrote: > Hello, > > I tried that as well but there are no tsan warnings thrown at run time, even > though there are data race error! > > The steps I followed: > 1. Generate bitcode using 'clang -emit-llvm' command > 2. Using the 'opt -load ..' command, I instrumented the

I think the code is not getting instrumented with tsan at all. In the 'step 3', when I instrument it using 'opt -tsan ...', it gives a warning "WARNING: You're attempting to print out a bitcode file." I guess this method doesn't instrument the code. Is there any other way I can instrument the code with tsan? On Monday, July 10, 2017 at 7:21:28 AM UTC+2,

> Assume I instrument some instructions by using some transformation passes. > At runtime, I just need those instrumented instructions at the beginning, > and I would like to remove instrumented instructions at runtime to reduce > overhead. At the beginning of what? You mean at the time of program starup? Then after detecting/collecting whatever you want, you would like to remove

hi, I'm newer in llvm i would like to instrument a byte code with a pass and as a result i would like to get an instrumented byte code. i would like that a pass add a method (which calculate the number of instructions) in the end of each block. the instrumented code should contain in each block a method that calculate the number of instructions Please Help me thank you -- Nabila ABDESSAIED

Hi, I'm a student who is going to make a countermeasure for dangling pointers in c for his thesis. I need to make my source transformation using llvm. Nobody in my university already used LLVM. I already read a some documentation about llvm but i'm still lost. Do there exist some " examples/Tutorials" for making small source transformations. Or is there somebody who can help

Hi All , I'm not sure the question is relevant to the forum,My apologies if not We are trying to instrument our code with ASan(Clang) to find the memory errors and we see that the application execution halts when the Asan check finds the memory issue at the being. Which mean we need to fix the issue then compile and execute the instrumented code again to find the next issue and so on

> We seem to have some agreement that two formats for instrumentation > based profiling is worthwhile. These are that emitted by compiler-rt in > the instrumented program at runtime (format 1), and that which is > consumed by clang when compiling the program with PGO (format 2). > > Format 1 > -------- > > This format should be efficient to write, since the

On 6/18/2017 3:51 PM, Vedant Kumar wrote: >> My experience: >> >> 1. You have to specify -DLLVM_USE_LINKER=gold (or maybe lld works; I >> didn't try). If you link with binutils ld, the program will generate >> broken profile information. Apparently, the linked binary is missing >> the __llvm_prf_names section. This took me half a day to figure out.

Hi, I've seen on the LLVM's Open Projet Page [1] an idea about using LLVM to generate native code in Valgrind. For what I know, Valgrind uses libVEX to translate native instructions into a bitcode, used to add the instrumentation and then translated back to native code for execution. Valgrind and LLVM are two tools that I use nearly every day. I'm also very interested in code

Hello, I have a question regarding PGO instrumented BBs (I use IR-level instrumentation). It seems that instrumented BBs do not match between the two compilations for profile-gen and profile-use for some cases. Here is an example from SPECcpu 2006 lbm (a simple case consisting of just two modules). In the first compilation, we have 5 instrumentation points for the main function as follows: $

On Tue, Mar 16, 2010 at 6:57 PM, Chris Lattner <clattner at apple.com> wrote: > > The "tail" marker has a very specific description in LLVM IR: it says that the caller does not access the callee's stack: > http://llvm.org/docs/LangRef.html#i_call Ah that makes more sense. Thanks for the pointer. > > 2) When I instrument the code using my opt pass, none of the

Hello all, I have developed a instrumented pass which insert some variables between the original variables, as well as insert some code into the original source code. just like: ============= original source code ============= int a[10]; void fun1 () { // some source code here } ========================================= ============= instrumented source code ============= int

Hello, We have a user that wants to get the code coverage report for his library without turning on instrumentation for the library clients or change how they are built (only the library is instrumented). It seems like the inline member functions defined in headers are not instrumented in this case because the clients are not instrumented. The library itself does not have a copy of the inline

Hi All: In Solaris Dtrace User Guide, page 218, it says, "Functions that do not create a stack frame on x86 systems cannot be instrumented by FBT." Then what are these functions? What characteristics do they have? Regards TJ