xref: /llvm-project/openmp/docs/remarks/OMP140.rst (revision 0c660256eb41fb0ba44277a32f39d2a028f797f2)
1.. _omp140:
2
3Could not internalize function. Some optimizations may not be possible. [OMP140]
4====================================================================================================================
5
6This analysis remark indicates that function internalization failed for the
7given function. Internalization occurs when a call to a function that ordinarily
8has external visibility is replaced with a call to a copy of that function with
9only internal visibility. This allows the compiler to make strong static
10assertions about the context a function is called in. Without internalization
11this analysis would always be invalidated by the possibility of someone calling
12the function in a different context outside of the current translation unit.
13This is necessary for optimizations like :ref:`OMP111 <omp111>` and :ref:`OMP120
14<omp120>`. If a function failed to be internalized it most likely has linkage
15that cannot be copied. Internalization is currently only enabled by default for
16OpenMP target offloading.
17
18Examples
19--------
20
21This will occur for any function declaration that has incompatible linkage.
22
23.. code-block:: c++
24
25   __attribute__((weak)) void setup();
26
27   void foo() {
28   #pragma omp target
29   {
30     setup();
31     #pragma omp parallel
32     {
33       work();
34     }
35   }
36   }
37
38.. code-block:: console
39
40   $ clang++ -fopenmp -fopenmp-targets=nvptx64 -O1 -Rpass-analysis=openmp-opt omp140.cpp
41   omp140.cpp:1:1: remark: Could not internalize function. Some optimizations may not
42   be possible. [OMP140]
43   __attribute__((weak)) void setup() {
44   ^
45
46Diagnostic Scope
47----------------
48
49OpenMP analysis remark.
50