nsz Git - libfirm/blob - support/libfirmprof/instrument.c

   1 /**
   2  * Helper code to output instrumentation results
   3  *  @author Matthias Braun, Steven Schaefer
   4  */
   5 #include <stdio.h>
   6 #include <string.h>
   7 #include <stdlib.h>
   8
   9 /* Prevent the compiler from mangling the name of this function. */
  10 void __init_firmprof(const char*, unsigned int*, size_t)
  11      asm("__init_firmprof");
  12
  13 typedef struct _profile_counter_t {
  14         const char *filename;
  15         unsigned   *counters;
  16         unsigned    len;
  17         struct _profile_counter_t *next;
  18 } profile_counter_t;
  19
  20 static profile_counter_t *counters = NULL;
  21
  22 /**
  23  * Write counter values to profiling output file.
  24  * We define our output format to be a sequence of 32-bit unsigned integer
  25  * values stored in little endian format.
  26  */
  27 void write_little_endian(unsigned *counter, unsigned len, FILE *f)
  28 {
  29         unsigned i;
  30
  31         for (i = 0; i < len; ++i) {
  32                 unsigned      v = counter[i];
  33                 unsigned char bytes[4];
  34
  35                 bytes[0] = ((v >>  0) & 0xff);
  36                 bytes[1] = ((v >>  8) & 0xff);
  37                 bytes[2] = ((v >> 16) & 0xff);
  38                 bytes[3] = ((v >> 24) & 0xff);
  39
  40                 fwrite(bytes, 1, 4, f);
  41         }
  42 }
  43
  44 static void write_profiles(void)
  45 {
  46         profile_counter_t *counter = counters;
  47         while (counter != NULL) {
  48                 profile_counter_t *next = counter->next;
  49                 FILE *f = fopen(counter->filename, "wb");
  50                 if (f == NULL) {
  51                         perror("Warning: couldn't open file for writing profiling data");
  52                 } else {
  53                         fputs("firmprof", f);
  54                         write_little_endian(counter->counters, counter->len, f);
  55                         fclose(f);
  56                 }
  57                 free(counter);
  58                 counter = next;
  59         }
  60 }
  61
  62 /**
  63  * Register a new profile counter. This is called by separate constructors
  64  * for each translation unit. Incidentally, referring to this function as
  65  * "__init_firmprof" is perfectly linker friendly.
  66  */
  67 void __init_firmprof(const char *filename,
  68                       unsigned int *counts, size_t len)
  69 {
  70         static int initialized = 0;
  71         profile_counter_t *counter;
  72
  73         if (!initialized) {
  74                 initialized = 1;
  75                 atexit(write_profiles);
  76         }
  77
  78         counter = (profile_counter_t*) malloc(sizeof(*counter));
  79         if (counter == NULL)
  80                 return;
  81
  82         counter->filename = filename;
  83         counter->counters = counts;
  84         counter->next     = counters;
  85         counter->len      = len;
  86
  87         counters = counter;
  88 }