| Issue |
134226
|
| Summary |
The issue of the runtime execution of the __llvm_defilew_rite_file() function affecting the collection of coverage
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
Kurtcobainzl
|
I am implementing a demo to collect coverage during runtime, but I found that when I execute the `__llvm_profile_write_file();` function, it causes the coverage data to be inaccurate. Below is my demo. After starting the program without performing any actions, the line printf("Invalid input, please try again.\n"); is shown as covered. I suspect that the execution of the` __llvm_profile_write_file(); `function is affecting the coverage results.
Here are the version information for my relevant tools, machine details, source code, commands, and the phenomenon. I would really like to know where the issue lies. Thank you.
version: Mac OS & Apple M4 Pro chip.
`oker@okerdeMacBook-Pro ~ % clang++ --version
Homebrew clang version 20.1.1
Target: arm64-apple-darwin24.2.0
Thread model: posix
InstalledDir: /opt/homebrew/Cellar/llvm/20.1.1/bin
Configuration file: /opt/homebrew/etc/clang/arm64-apple-darwin24.cfg
oker@okerdeMacBook-Pro ~ % llvm-profdata --version
Homebrew LLVM version 20.1.1
Optimized build.
oker@okerdeMacBook-Pro ~ % llvm-cov --version
Homebrew LLVM version 20.1.1
Optimized build.
`
and here is code ，It will execute __llvm_profile_write_file(); every 5 seconds to collect coverage information
`#include <stdio.h>
#include <stdint.h>
#include <execinfo.h>
#include <string.h>
#include <signal.h>
#include <thread>
#include <chrono>
#include <atomic>
// Pre-declaration for Clang coverage interface
extern "C" int __llvm_profile_write_file(void);
std::atomic<bool> stop_thread(false);
// Periodic coverage data writing thread
void timerThread() {
while (!stop_thread) {
std::this_thread::sleep_for(std::chrono::seconds(5)); // run every 5 seconds
__llvm_profile_write_file();
}
}
void foo() {
printf("foo()\n");
}
void bar() {
printf("bar()\n");
}
void runUserLoop() {
while (true) {
printf("Please enter 1 to call foo(), 2 to call bar(), 3 to exit: ");
int choice = 0;
scanf("%d", &choice);
if (choice == 1) {
foo();
} else if (choice == 2) {
bar();
} else if (choice == 3) {
break;
} else {
printf("Invalid input, please try again.\n");
}
}
}
int main() {
std::thread timer(timerThread); // start timer thread
runUserLoop();
return 0;
}`
Below are the commands I used to execute it, and after it runs, I did not perform any actions, waiting for 10 seconds before executing the command to collect coverage data
`clang++ -fsanitize=address -fsanitize-coverage=trace-pc-guard \
-fprofile-instr-generate -fcoverage-mapping \
demo.cpp -o demo
export ASAN_OPTIONS=coverage=1:coverage_dir=./covdata
export LLVM_PROFILE_MERGE=1
mkdir -p covdata
./demo`
`llvm-profdata merge -sparse covdata/*.profraw -o demo.profdata
llvm-cov show ./demo -instr-profile=""
`
![]()
_______________________________________________
llvm-bugs mailing list
llvm-bugs@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
