runtime/libprofile/BlockProfiling.c

   1 /*===-- BlockProfiling.c - Support library for block 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 block profiling
  11 |* instrumentation pass.  This should be used with the -insert-block-profiling
  12 |* LLVM pass.
  13 |*
  14 \*===----------------------------------------------------------------------===*/
  15
  16 #include "Profiling.h"
  17 #include <stdlib.h>
  18
  19 static unsigned *ArrayStart;
  20 static unsigned NumElements;
  21
  22 /* BlockProfAtExitHandler - When the program exits, just write out the profiling
  23  * data.
  24  */
  25 static void BlockProfAtExitHandler() {
  26   /* Note that if this were doing something more intelligent with the
  27    * instrumentation, we could do some computation here to expand what we
  28    * collected into simple block profiles. (Or we could do it in llvm-prof.)
  29    * Regardless, we directly count each block, so no expansion is necessary.
  30    */
  31   write_profiling_data(BlockInfo, ArrayStart, NumElements);
  32 }
  33
  34
  35 /* llvm_start_block_profiling - This is the main entry point of the block
  36  * profiling library.  It is responsible for setting up the atexit handler.
  37  */
  38 int llvm_start_block_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(BlockProfAtExitHandler);
  44   return Ret;
  45 }