1/*===-- CommonProfiling.c - Profiling support library support -------------===*\
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 functions used by the various different types of
11|* profiling implementations.
12|*
13\*===----------------------------------------------------------------------===*/
14
15#include "Profiling.h"
16#include <assert.h>
17#include <sys/types.h>
18#include <sys/stat.h>
19#include <fcntl.h>
20#include <stdio.h>
21#include <string.h>
22#if !defined(_MSC_VER) && !defined(__MINGW32__)
23#include <unistd.h>
24#else
25#include <io.h>
26#endif
27#include <stdlib.h>
28
29static char *SavedArgs = 0;
30static unsigned SavedArgsLength = 0;
31static const char *SavedEnvVar = 0;
32
33static const char *OutputFilename = "llvmprof.out";
34
35/* check_environment_variable - Check to see if the LLVMPROF_OUTPUT environment
36 * variable is set.  If it is then save it and set OutputFilename.
37 */
38static void check_environment_variable(void) {
39  const char *EnvVar;
40  if (SavedEnvVar) return; /* Guarantee that we can't leak memory. */
41
42  if ((EnvVar = getenv("LLVMPROF_OUTPUT")) != NULL) {
43    /* The string that getenv returns is allowed to be statically allocated,
44     * which means it may be changed by future calls to getenv, so copy it.
45     */
46    SavedEnvVar = strdup(EnvVar);
47    OutputFilename = SavedEnvVar;
48  }
49}
50
51/* save_arguments - Save argc and argv as passed into the program for the file
52 * we output.
53 * If either the LLVMPROF_OUTPUT environment variable or the -llvmprof-output
54 * command line argument are set then change OutputFilename to the provided
55 * value.  The command line argument value overrides the environment variable.
56 */
57int save_arguments(int argc, const char **argv) {
58  unsigned Length, i;
59  if (!SavedEnvVar && !SavedArgs) check_environment_variable();
60  if (SavedArgs || !argv) return argc;  /* This can be called multiple times */
61
62  /* Check to see if there are any arguments passed into the program for the
63   * profiler.  If there are, strip them off and remember their settings.
64   */
65  while (argc > 1 && !strncmp(argv[1], "-llvmprof-", 10)) {
66    /* Ok, we have an llvmprof argument.  Remove it from the arg list and decide
67     * what to do with it.
68     */
69    const char *Arg = argv[1];
70    memmove((char**)&argv[1], &argv[2], (argc-1)*sizeof(char*));
71    --argc;
72
73    if (!strcmp(Arg, "-llvmprof-output")) {
74      if (argc == 1)
75        puts("-llvmprof-output requires a filename argument!");
76      else {
77        OutputFilename = strdup(argv[1]);
78        if (SavedEnvVar) { free((void *)SavedEnvVar); SavedEnvVar = 0; }
79        memmove((char**)&argv[1], &argv[2], (argc-1)*sizeof(char*));
80        --argc;
81      }
82    } else {
83      printf("Unknown option to the profiler runtime: '%s' - ignored.\n", Arg);
84    }
85  }
86
87  for (Length = 0, i = 0; i != (unsigned)argc; ++i)
88    Length += strlen(argv[i])+1;
89
90  /* Defensively check for a zero length, even though this is unlikely
91   * to happen in practice.  This avoids calling malloc() below with a
92   * size of 0.
93   */
94  if (Length == 0) {
95    SavedArgs = 0;
96    SavedArgsLength = 0;
97    return argc;
98  }
99
100  SavedArgs = (char*)malloc(Length);
101  for (Length = 0, i = 0; i != (unsigned)argc; ++i) {
102    unsigned Len = strlen(argv[i]);
103    memcpy(SavedArgs+Length, argv[i], Len);
104    Length += Len;
105    SavedArgs[Length++] = ' ';
106  }
107
108  SavedArgsLength = Length;
109
110  return argc;
111}
112
113
114/*
115 * Retrieves the file descriptor for the profile file.
116 */
117int getOutFile() {
118  static int OutFile = -1;
119
120  /* If this is the first time this function is called, open the output file
121   * for appending, creating it if it does not already exist.
122   */
123  if (OutFile == -1) {
124    OutFile = open(OutputFilename, O_CREAT | O_WRONLY, 0666);
125    lseek(OutFile, 0, SEEK_END); /* O_APPEND prevents seeking */
126    if (OutFile == -1) {
127      fprintf(stderr, "LLVM profiling runtime: while opening '%s': ",
128              OutputFilename);
129      perror("");
130      return(OutFile);
131    }
132
133    /* Output the command line arguments to the file. */
134    {
135      int PTy = ArgumentInfo;
136      int Zeros = 0;
137      if (write(OutFile, &PTy, sizeof(int)) < 0 ||
138          write(OutFile, &SavedArgsLength, sizeof(unsigned)) < 0 ||
139          write(OutFile, SavedArgs, SavedArgsLength) < 0 ) {
140        fprintf(stderr,"error: unable to write to output file.");
141        exit(0);
142      }
143      /* Pad out to a multiple of four bytes */
144      if (SavedArgsLength & 3) {
145        if (write(OutFile, &Zeros, 4-(SavedArgsLength&3)) < 0) {
146          fprintf(stderr,"error: unable to write to output file.");
147          exit(0);
148        }
149      }
150    }
151  }
152  return(OutFile);
153}
154
155/* write_profiling_data - Write a raw block of profiling counters out to the
156 * llvmprof.out file.  Note that we allow programs to be instrumented with
157 * multiple different kinds of instrumentation.  For this reason, this function
158 * may be called more than once.
159 */
160void write_profiling_data(enum ProfilingType PT, unsigned *Start,
161                          unsigned NumElements) {
162  int PTy;
163  int outFile = getOutFile();
164
165  /* Write out this record! */
166  PTy = PT;
167  if( write(outFile, &PTy, sizeof(int)) < 0 ||
168      write(outFile, &NumElements, sizeof(unsigned)) < 0 ||
169      write(outFile, Start, NumElements*sizeof(unsigned)) < 0 ) {
170    fprintf(stderr,"error: unable to write to output file.");
171    exit(0);
172  }
173}
174