llvm-project/compiler-rt/lib/profile/InstrProfiling.c

49 lines
1.5 KiB
C

/*===- InstrProfiling.c - Support library for PGO instrumentation ---------===*\
|*
|* The LLVM Compiler Infrastructure
|*
|* This file is distributed under the University of Illinois Open Source
|* License. See LICENSE.TXT for details.
|*
\*===----------------------------------------------------------------------===*/
#include "InstrProfiling.h"
#include <string.h>
__attribute__((visibility("hidden")))
uint64_t __llvm_profile_get_magic(void) {
/* Magic number to detect file format and endianness.
*
* Use 255 at one end, since no UTF-8 file can use that character. Avoid 0,
* so that utilities, like strings, don't grab it as a string. 129 is also
* invalid UTF-8, and high enough to be interesting.
*
* Use "lprofr" in the centre to stand for "LLVM Profile Raw", or "lprofR"
* for 32-bit platforms.
*/
unsigned char R = sizeof(void *) == sizeof(uint64_t) ? 'r' : 'R';
return
(uint64_t)255 << 56 |
(uint64_t)'l' << 48 |
(uint64_t)'p' << 40 |
(uint64_t)'r' << 32 |
(uint64_t)'o' << 24 |
(uint64_t)'f' << 16 |
(uint64_t) R << 8 |
(uint64_t)129;
}
__attribute__((visibility("hidden")))
uint64_t __llvm_profile_get_version(void) {
/* This should be bumped any time the output format changes. */
return 1;
}
__attribute__((visibility("hidden")))
void __llvm_profile_reset_counters(void) {
uint64_t *I = __llvm_profile_begin_counters();
uint64_t *E = __llvm_profile_end_counters();
memset(I, 0, sizeof(uint64_t)*(E - I));
}