xref: /aosp_15_r20/system/extras/toolchain-extras/profile-clang-extras.cpp (revision 288bf5226967eb3dac5cce6c939ccc2a7f2b4fe5)
1 /*
2  * Copyright (C) 2020 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include <errno.h>
18 #include <signal.h>
19 #include <stdlib.h>
20 
21 #include "profile-extras.h"
22 
23 extern "C" {
24 
25 static sighandler_t chained_signal_handler = SIG_ERR;
26 
27 #ifndef __CONTINUOUS_COVERAGE_MODE__
28 int __llvm_profile_write_file(void);
29 #endif  // __CONTINUOUS_COVERAGE_MODE__
30 
llvm_signal_handler(__unused int signum)31 static void llvm_signal_handler(__unused int signum) {
32   // TODO(pirama) Only disable __llvm_profile_write_file call to begin with.
33   // After continuous mode is stable, stop registering the signal handler.
34 #ifndef __CONTINUOUS_COVERAGE_MODE__
35   __llvm_profile_write_file();
36 #endif  // __CONTINUOUS_COVERAGE_MODE__
37 
38   if (chained_signal_handler != SIG_ERR && chained_signal_handler != SIG_IGN &&
39       chained_signal_handler != SIG_DFL) {
40     (chained_signal_handler)(signum);
41   }
42 }
43 
44 // Initialize libprofile-extras:
45 //
46 // - Install a signal handler that triggers __llvm_profile_write_file on
47 // <COVERAGE_FLUSH_SIGNAL>.
48 //
49 // We want this initializer to run during load time.  In addition to marking
50 // this function as a constructor, we link this library with `--whole-archive`
51 // to force this function to be included in the output.
init_profile_extras(void)52 static __attribute__((constructor)) int init_profile_extras(void) {
53   if (chained_signal_handler != SIG_ERR) {
54     return -1;
55   }
56   sighandler_t ret1 = signal(COVERAGE_FLUSH_SIGNAL, llvm_signal_handler);
57   if (ret1 == SIG_ERR) {
58     return -1;
59   }
60   chained_signal_handler = ret1;
61 
62   return 0;
63 }
64 }
65