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
20 static 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 */
WriteAndFlushBBTraceData()25 static 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 */
BBTraceAtExitHandler(void)33 static void BBTraceAtExitHandler(void) {
34 WriteAndFlushBBTraceData ();
35 free (ArrayStart);
36 }
37
38 /* llvm_trace_basic_block - called upon hitting a new basic block. */
llvm_trace_basic_block(unsigned BBNum)39 void 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 */
llvm_start_basic_block_tracing(int argc,const char ** argv,unsigned * arrayStart,unsigned numElements)49 int 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