search for: thread_locals

Hi all, I've been exploring thread local globals in llvm and as part of this investigation I ran llc -march=cpp over a trivial llvm bc file which uses thread local storage for a global. For some reason llc -march=cpp seems to ignore the thread_local and produce code to create a standard global. Is this expected behaviour, a known limitation, or otherwise? Thanks in advance. Details are as

Hi LLVM, I am using 3.0, and I have a question about the __thread in c and thread_local in LLVM IR: O1-O4 and the final linked code behave differently. //////////////////////////////////// The following C code is from the LLVM testcase (SingleSource/UnitTests/Threads/2010-12-08-tls.c) #include <stdio.h> __thread int a = 4; int foo (void) { return a; } int main (void) {

For everyone understand which code must be emitted to implement TLS, I will paste the code generated by gcc for a simple function: __thread int a = 1; int f(){ return a; } gcc teste.c -o teste.s -S -O2 (arm-linux-gnueabi): .global a .section .tdata,"awT",%progbits <== special section for tls symbols .align 2 .type a, %object

I note also that this is not a currently unsupported target case where an error should/could/would be produced on attempting to emit code with thread local references. I say this because clang is able to compile both c source with __thread on a global and bc containing a @variable = thread_local global ... and a function that references the thread local global variable to both assembly and machine

target triple = "i386-pc-linux-gnu" On 13/05/2010, at 9:25 PM, Anton Korobeynikov wrote: >> int (*FP)() = (int (*)())FPtr; >> int res = FP(); >> >> when the function executes correctly in the case of instead having created a standard global variable. > What is the platform you're running the code on? > > -- > With best regards, Anton

> I note also that this is not a currently unsupported target case where an error should/could/would be produced on attempting to emit code with thread local references. I say this because clang is able to compile both c source with __thread on a global and bc containing a @variable = thread_local global ... and a function that references the thread local global variable to both assembly and

...n terms of LLVM's design, I've noticed that thread_local variables are represented in the same way as ordinary variables (via llvm::GlobalVariable) except that the "isThreadLocal" flag is true. This strikes me as a potential for confusion, because you have this one corner case -- thread_locals -- in which an "llvm::Constant" is not really a "constant" in the same way as other constants. This might be related to http://llvm.org/bugs/show_bug.cgi?id=13720, and perhaps a few other bugs. -Tom p.s. If anyone is hit by this bug, my current workaround is to declare Ptr vo...

We know that in C++, the constructor of a static member will get called when the program starts up. I checked the generated IR code and found this is implemented by defining a __cxx_global_var_init() function and marked it as section ".text.startup" and assign it to @llvm.global_ctors. We also know that in C++, the constructor of a static thread_local member will *not* get called when

Hello > I've been exploring thread local globals in llvm and as part of this investigation I ran llc -march=cpp over a trivial llvm bc file which uses thread local storage for a global. For some reason llc -march=cpp seems to ignore the thread_local and produce code to create a standard global. Is this expected behaviour, a known limitation, or otherwise? Thanks for the report. Should be

Hi all, I would like to hear your thoughts on adding support for extending the IR to allow for explicitly selecting which model to use for thread-local storage of a variable. The motivation is to allow Clang to support the "tls_model" variable attribute [1], as requested in PR9788. The idea would be to extend the IR to allow an optional TLS-model argument to the thread_local

Thanks for the quick reply and fix. Now it just means I have to hunt further in exploring why, in my simple test program, replacing the following line of code: GlobalVariable* global = new GlobalVariable(*MyModule, IntegerType::get(getGlobalContext(), 32), false, GlobalValue::ExternalLinkage, 0, "global"); with the following line of code: GlobalVariable* global = new

> From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] > On Behalf Of Tom Bergan > Subject: [LLVMdev] Bug Report -- Possible optimizer bug with thread_local variables > my current workaround is to declare Ptr volatile: >    int * volatile Ptr; > Note that if the volatile is moved under the pointer, as in the following: >    volatile int * Ptr; >

hi guys, i wrote a small program that can load the *.ll file, parse it and execute it. but there is a thread_local global variable. during execution, it says: Cannot allocate thread local storage on this arch! UNREACHABLE executed at /root/llvm/lib/Target/X86/X86JITInfo.cpp:585!. it seems that i did not initialize the executionEngine right or i shouldnot use InitializeNativeTarget()? i

Hi, This weekend, I've noticed that GlobalVariable's could be declared as thread-local in LLVM 2.0. However, when using it on a small example (OSX), I got the following error: ========= Cannot yet select: 0x56059f0: i32 = GlobalTLSAddress <i32* @a> 0 Abort trap ========= This is the example code: ========= ; ModuleID = 'test.o' target datalayout =

Hello, The preferred way to do TLS is to use the thread_local keyword. There is x86-64 support for thread_local on ELF; if you need it for other targets, I recommend looking at adapting it. Dan On May 4, 2009, at 2:59 PM, Zoltan Varga wrote: > Hi, > > Here is an updated version of the patch using address space 257. > > Zoltan > > On Mon, May 4, 2009 at

On Sun, Dec 4, 2011 at 9:18 AM, Kai <kai at redstar.de> wrote: > Hi! > > LLVM currently does not implement the implicit TLS model on Windows. This > model is easy: > > - a thread local variable ends up in the .tls section > - to access a thread local variable, you have to do >  (1) load pointer to thread local storage from TEB >      On x86_64, this is gs:0x58, on

Hi Tom, On Wed, Nov 7, 2012 at 11:43 PM, Tom Bergan <tbergan at cs.washington.edu> wrote: > Hello, > > I apologize if this has already been fixed or reported. I believe there is > a bug in the way the optimizer deals with thread_local variables. The > attached program, test.c, has a thread-local variable "int Foo" and a global > variable "int *Ptr".

Hi, If I'm writing a JIT, and want to access the TLS variables of the app containing the JIT, I can't use thread_local since that only works for variables declared in LLVM IL and/or managed by the ExecutionEngine. While this patch allows a JIT to generate the TLS accesses itself, if it knows the tls offset of the variable in question. Zoltan On Tue, May 5, 2009 at

> I’ve seen the same problem, but didn’t find solution back then. > I can give a hint that it is related to a thread local storage (notice TLS in the name). > > The same result can be reproduced by this simple program: > > thread_local int x = 0; > int main() { > return 0; > } > >When compiled into IR it produces similar error: > >LLVM ERROR:

I'm learning the xray library and try if it can be built on windows, in xray_fdr_logging_impl.h line 152 , comment written as // Using pthread_once(...) to initialize the thread-local data structures but at line 175, 183, code written as thread_local pthread_key_t key; // Ensure that we only actually ever do the pthread initialization once. thread_local bool UNUSED Unused = [] {