runtime/libprofile/OptimalEdgeProfiling.c

   1 /*===-- OptimalEdgeProfiling.c - Support library for opt. edge profiling --===*\
   2 |*
   3 |*                     The LLVM Compiler Infrastructure
   4 |*
   5 |* This file is distributed under the University of Illinois Open Source
   6 |* License. See LICENSE.TXT for details.
   7 |*
   8 |*===----------------------------------------------------------------------===*|
   9 |*
  10 |* This file implements the call back routines for the edge profiling
  11 |* instrumentation pass.  This should be used with the
  12 |* -insert-opt-edge-profiling LLVM pass.
  13 |*
  14 \*===----------------------------------------------------------------------===*/
  15
  16 #include "Profiling.h"
  17 #include <stdlib.h>
  18
  19 static unsigned *ArrayStart;
  20 static unsigned NumElements;
  21
  22 /* OptEdgeProfAtExitHandler - When the program exits, just write out the
  23  * profiling data.
  24  */
  25 static void OptEdgeProfAtExitHandler() {
  26   /* Note that, although the array has a counter for each edge, not all
  27    * counters are updated, the ones that are not used are initialised with -1.
  28    * When loading this information the counters with value -1 have to be
  29    * recalculated, it is guranteed that this is possible.
  30    */
  31   write_profiling_data(OptEdgeInfo, ArrayStart, NumElements);
  32 }
  33
  34
  35 /* llvm_start_opt_edge_profiling - This is the main entry point of the edge
  36  * profiling library.  It is responsible for setting up the atexit handler.
  37  */
  38 int llvm_start_opt_edge_profiling(int argc, const char **argv,
  39                                   unsigned *arrayStart, unsigned numElements) {
  40   int Ret = save_arguments(argc, argv);
  41   ArrayStart = arrayStart;
  42   NumElements = numElements;
  43   atexit(OptEdgeProfAtExitHandler);
  44   return Ret;
  45 }