1/*===-- BasicBlockTracing.c - Support library for basic block tracing -----===*\ 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 basic block tracing 11|* instrumentation pass. This should be used with the -trace-basic-blocks 12|* LLVM pass. 13|* 14\*===----------------------------------------------------------------------===*/ 15 16#include "Profiling.h" 17#include <stdlib.h> 18#include <stdio.h> 19 20static unsigned *ArrayStart, *ArrayEnd, *ArrayCursor; 21 22/* WriteAndFlushBBTraceData - write out the currently accumulated trace data 23 * and reset the cursor to point to the beginning of the buffer. 24 */ 25static void WriteAndFlushBBTraceData () { 26 write_profiling_data(BBTraceInfo, ArrayStart, (ArrayCursor - ArrayStart)); 27 ArrayCursor = ArrayStart; 28} 29 30/* BBTraceAtExitHandler - When the program exits, just write out any remaining 31 * data and free the trace buffer. 32 */ 33static void BBTraceAtExitHandler(void) { 34 WriteAndFlushBBTraceData (); 35 free (ArrayStart); 36} 37 38/* llvm_trace_basic_block - called upon hitting a new basic block. */ 39void llvm_trace_basic_block (unsigned BBNum) { 40 *ArrayCursor++ = BBNum; 41 if (ArrayCursor == ArrayEnd) 42 WriteAndFlushBBTraceData (); 43} 44 45/* llvm_start_basic_block_tracing - This is the main entry point of the basic 46 * block tracing library. It is responsible for setting up the atexit 47 * handler and allocating the trace buffer. 48 */ 49int llvm_start_basic_block_tracing(int argc, const char **argv, 50 unsigned *arrayStart, unsigned numElements) { 51 int Ret; 52 const unsigned BufferSize = 128 * 1024; 53 unsigned ArraySize; 54 55 Ret = save_arguments(argc, argv); 56 57 /* Allocate a buffer to contain BB tracing data */ 58 ArraySize = BufferSize / sizeof (unsigned); 59 ArrayStart = malloc (ArraySize * sizeof (unsigned)); 60 ArrayEnd = ArrayStart + ArraySize; 61 ArrayCursor = ArrayStart; 62 63 /* Set up the atexit handler. */ 64 atexit (BBTraceAtExitHandler); 65 66 return Ret; 67} 68