jdoerfert added inline comments.

================
Comment at: openmp/runtime/test/tasking/kmp_taskloop.c:100
         th_counter[i] = 0;
-    #pragma omp parallel num_threads(N)
+    #pragma omp parallel // num_threads(N)
     {
----------------
jhuber6 wrote:
> AndreyChurbanov wrote:
> > jhuber6 wrote:
> > > jhuber6 wrote:
> > > > jdoerfert wrote:
> > > > > jhuber6 wrote:
> > > > > > I am not entirely sure why, but commenting this out causes the 
> > > > > > problem to go away. I tried adding proper names to the 
> > > > > > forward-declared functions but since clang already knew I had 
> > > > > > something called ident_t, I couldn't declare a new struct with the 
> > > > > > same name.
> > > > > This is not good. The difference should only be that the 
> > > > > `kmpc_fork_call` has a different argument, right? Does the segfault 
> > > > > happen at compile or runtime?
> > > > > 
> > > > > You can just use the ident_t clang created, right? Did you print the 
> > > > > function names requested by clang as we discussed?
> > > > I added an assertion and debug statements. If I try to declare a struct 
> > > > named "Ident_t" I get the following error message in the seg-fault. I 
> > > > think the seg-fault is compile-time.
> > > > 
> > > > Found OpenMP runtime function __kmpc_global_thread_num with type i32 
> > > > (%struct.ident_t.0*). Expected type is i32 (%struct.ident_t*)
> > > > clang: 
> > > > /home/jhuber/Documents/llvm-project/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp:124:
> > > >  static llvm::Function* 
> > > > llvm::OpenMPIRBuilder::getOrCreateRuntimeFunction(llvm::Module&, 
> > > > llvm::omp::RuntimeFunction): Assertion `FnTy == Fn->getFunctionType() 
> > > > && "Found OpenMP runtime function has mismatched types"' failed.
> > > I'm not sure if there's a way around this without changing the 
> > > getOrCreateRuntimeFunction method to return a FunctionCallee and removing 
> > > the assertion. Clang doesn't know about the ident_t struct when it's 
> > > compiling the file, but when its doing the codegen it sees two structs 
> > > with the same name and creates a new name. So when it gets the types it 
> > > says that ident_t and ident_t.0 don't match. As you said the old version 
> > > got around this by adding a bitcasting instruction so it knew how to turn 
> > > it into an ident_t pointer.
> > Note that this change breaks the test on any system with more that 4 procs. 
> >  Because array th_counter[4] is indexed by thread number which can easily 
> > be greater than 3 if number of threads is not limited.
> The problem was that the num_threads clause required an implicit call to 
> kmpc_global_thread_num so it could be passed to kmpc_push_num_threads. The 
> types of the implicit function and the forward declaration then wouldn't 
> match up. I added another forward declaration to explicitly call 
> kmpc_push_num_threads. Is this a sufficient solution?
We need this to work with num_threads(8). 

> Clang doesn't know about the ident_t struct when it's compiling the file, but 
> when its doing the codegen it sees two structs with the same name and creates 
> a new name.

Where are the two structs coming from? We should have one. If clang introduces 
one it needs to use the one from OMPKindes.def instead. Is that a fix?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D80222/new/

https://reviews.llvm.org/D80222



_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits

Reply via email to