jhuber6 marked an inline comment as done.
jhuber6 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)
{
----------------
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?
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D80222/new/
https://reviews.llvm.org/D80222
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