Check Your Understanding

This purpose of this practical is to test your understanding of working with OpenMP types with ROSE. You will implement a simple tool that traverses the AST and looks for an OpenMP directive.

This is an “open-book” exercise and you may use the terminal and any resources. The ROSE API may be particularly useful.

Task

Implement a ROSE translator that traverses the AST and counts the number of OpenMP parallel for directives. Run your translator with the following input code:

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#include < stdio.h >
#include < omp.h >
#define N 1000000
int main(void) {
  float a[N], b[N], c[N], d[N];
  int i;
  int j;

  for (i = 0; i < N; i++) {
    a[i] = i * 2.0;
    b[i] = i * 3.0;
  }

  #pragma omp parallel shared(a, b, c) private(i)
  {
    #pragma omp for             
    for (i = 0; i < N; i++) {
      c[i] = a[i] + b[i];
    }
  }

  #pragma omp parallel for private(j)
  for (int j = 0; j < N; j++) {
    d[j] = a[i] * b[i];
  }
}

Print the number of parallel for directives. The expected output is 2 for this test case.

Setting Up The Environment

Some starter code and a corresponding makefile is available for your usage. The following commands will obtain the skeleton source code for your translator parallelForCounter and save it to the ${ROSE_SRC}/practicals directory. The corresponding makefile is also saved to ${ROSE_BUILD}/practicals, as well as the input source code above as parallelFor_input.c in the same directory.

mkdir ${ROSE_BUILD}/practicals && cd "$_"
wget https://raw.githubusercontent.com/freeCompilerCamp/code-for-rose-tutorials/master/practicals/openmp-traversal/Makefile
wget https://raw.githubusercontent.com/freeCompilerCamp/code-for-rose-tutorials/master/practicals/openmp-traversal/parallelFor_input.c
mkdir ${ROSE_SRC}/practicals && cd "$_"
wget https://raw.githubusercontent.com/freeCompilerCamp/code-for-rose-tutorials/master/practicals/openmp-traversal/parallelForCounter.C

Make your changes directly to the parallelForCounter.C source file and insert your code following the comment "Insert your tool code here!". Vim, nano, and emacs are available within the terminal. When you are done, exit the text editor and return to the terminal.

Evaluation

To build your translator (without evaluation), run the following command.

cd ${ROSE_BUILD}/practicals
make

Your translator should report no errors (it may report warnings, but those can generally be ignored) if implemented correctly and an executable file named parallelForCounter should appear in the working directory.

Once you are ready, you should now run your implementation with the input code, and check its output, via

./parallelForCounter parallelFor_input.c

If your translator output a count of 2 parallel for directives, congratulations! You have completed the practical.