lib/profile/PGOProfiling.c

   1 /*===- PGOProfiling.c - Support library for PGO instrumentation -----------===*\
   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 #include <stdio.h>
  11 #include <stdlib.h>
  12
  13 #define I386_FREEBSD (defined(__FreeBSD__) && defined(__i386__))
  14
  15 #if !I386_FREEBSD
  16 #include <inttypes.h>
  17 #endif
  18
  19 #if !defined(_MSC_VER) && !I386_FREEBSD
  20 #include <stdint.h>
  21 #endif
  22
  23 #if defined(_MSC_VER)
  24 typedef unsigned int uint32_t;
  25 typedef unsigned int uint64_t;
  26 #elif I386_FREEBSD
  27 /* System headers define 'size_t' incorrectly on x64 FreeBSD (prior to
  28  * FreeBSD 10, r232261) when compiled in 32-bit mode.
  29  */
  30 #define PRIu64 "llu"
  31 typedef unsigned int uint32_t;
  32 typedef unsigned long long uint64_t;
  33 #endif
  34
  35 typedef struct __ProfileData {
  36   const uint32_t NameSize;
  37   const uint32_t NumCounters;
  38   const char *const Name;
  39   const uint64_t *const Counters;
  40 } __ProfileData;
  41
  42 /* TODO: Calculate these with linker magic. */
  43 static __ProfileData *First = NULL;
  44 static __ProfileData *Final = NULL;
  45 /*!
  46  * \brief Register an instrumented function.
  47  *
  48  * Calls to this are emitted by clang with -fprofile-instr-generate.  Such
  49  * calls are only required (and only emitted) on targets where we haven't
  50  * implemented linker magic to find the bounds of the section.
  51  *
  52  * For now, that's all targets.
  53  */
  54 void __llvm_pgo_register_function(void *Data_) {
  55   /* TODO: Only emit this function if we can't use linker magic. */
  56   __ProfileData *Data = (__ProfileData*)Data_;
  57   if (!First || Data < First)
  58     First = Data;
  59   if (!Final || Data > Final)
  60     Final = Data;
  61 }
  62
  63 /*! \brief Get the first instrumentation record. */
  64 static __ProfileData *getFirst() {
  65   /* TODO: Use extern + linker magic instead of a static variable. */
  66   return First;
  67 }
  68
  69 /*! \brief Get the last instrumentation record. */
  70 static __ProfileData *getLast() {
  71   /* TODO: Use extern + linker magic instead of a static variable. */
  72   return Final + 1;
  73 }
  74
  75 /* TODO: void __llvm_pgo_get_size_for_buffer(void);  */
  76 /* TODO: void __llvm_pgo_write_buffer(char *Buffer); */
  77
  78 static void writeFunction(FILE *OutputFile, const __ProfileData *Data) {
  79   /* TODO: Requires libc: break requirement by writing directly to a buffer
  80    * instead of a FILE stream.
  81    */
  82   uint32_t I;
  83   for (I = 0; I < Data->NameSize; ++I)
  84     fputc(Data->Name[I], OutputFile);
  85   fprintf(OutputFile, " %u\n", Data->NumCounters);
  86   for (I = 0; I < Data->NumCounters; ++I)
  87     fprintf(OutputFile, "%" PRIu64 "\n", Data->Counters[I]);
  88   fprintf(OutputFile, "\n");
  89 }
  90
  91 /*! \brief Write instrumentation data to the given file. */
  92 void __llvm_pgo_write_file(const char *OutputName) {
  93   /* TODO: Requires libc: move to separate translation unit. */
  94   __ProfileData *I, *E;
  95   FILE *OutputFile;
  96   if (!OutputName || !OutputName[0])
  97     return;
  98   OutputFile = fopen(OutputName, "w");
  99   if (!OutputFile) return;
 100
 101   /* TODO: mmap file to buffer of size __llvm_pgo_get_size_for_buffer() and
 102    * call __llvm_pgo_write_buffer().
 103    */
 104   for (I = getFirst(), E = getLast(); I != E; ++I)
 105     writeFunction(OutputFile, I);
 106
 107   fclose(OutputFile);
 108 }
 109
 110 /*! \brief Write instrumentation data to the default file. */
 111 void __llvm_pgo_write_default_file() {
 112   /* TODO: Requires libc: move to separate translation unit. */
 113   const char *OutputName = getenv("LLVM_PROFILE_FILE");
 114   if (OutputName == NULL || OutputName[0] == '\0')
 115     OutputName = "default.profdata";
 116   __llvm_pgo_write_file(OutputName);
 117 }
 118
 119 /*!
 120  * \brief Register to write instrumentation data to the default file at exit.
 121  */
 122 void __llvm_pgo_register_write_atexit() {
 123   /* TODO: Requires libc: move to separate translation unit. */
 124   static int HasBeenRegistered = 0;
 125
 126   if (!HasBeenRegistered) {
 127     HasBeenRegistered = 1;
 128     atexit(__llvm_pgo_write_default_file);
 129   }
 130 }
 131