https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108083
Bug ID: 108083
Summary: Code with memory leak does not get triggered when I
run the executable
Product: gcc
Version: 12.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: ssofroni at cytanet dot com.cy
Target Milestone: ---
I have a very weird behavior with gcc version 12.2.0 (Debian 12.2.0-9).
My code is the following:
#include <iostream>
int main()
{
[[maybe_unused]] int x{64};
std::cout << new char[]{"hi"};
return 0;
}
With my Makefile, I generate an executable with the following steps:
ccache g++ -Wall -Wextra -Werror -Wpedantic -std=c++20 -g -Og -D_GLIBCXX_DEBUG
-I src -c src/tmp.cpp -o obj/tmp.o
ccache g++ obj/tmp.o -o bin/tmp -fno-strict-aliasing -fwrapv -lfmt -lm
-fsanitize=address,undefined
If I execute `bin/tmp`, it prints 'hi' and does not trigger the sanitizer.
If I replace `g++` to `clang++`, the generated executable triggers the
sanitizer and catches the memory leak.
Here's the output:
hi
=================================================================
==12782==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 3 byte(s) in 1 object(s) allocated from:
#0 0x55fafedff07d in operator new[](unsigned long)
(/home/stefanos/code/cpp/tmp/bin/tmp+0xdf07d) (BuildId:
0903120ed7ac810b75b124e3d84396bbe7870f32)
#1 0x55fafee0156a in main /home/stefanos/code/cpp/tmp/src/tmp.cpp:6:18
SUMMARY: AddressSanitizer: 3 byte(s) leaked in 1 allocation(s).
To make GCC catch the leak, I either have to add a newline at the end of {"hi"}
or add `std::flush;`:
stefanos@debian:~/code/cpp/tmp $ cat src/tmp.cpp
#include <iostream>
int main()
{
[[maybe_unused]] int x{64};
std::cout << new char[]{"hi"} << '\n';
}
stefanos@debian:~/code/cpp/tmp $ make
ccache g++ -Wall -Wextra -Werror -Wpedantic -std=c++20 -g -Og -D_GLIBCXX_DEBUG
-I src -c src/tmp.cpp -o obj/tmp.o
ccache g++ obj/tmp.o -o bin/tmp -fno-strict-aliasing -fwrapv -lfmt -lm
-fsanitize=address,undefined
make -j4 --jobserver-auth=3,4 got executed in debug mode...
stefanos@debian:~/code/cpp/tmp $ bin/tmp
hi
=================================================================
==12975==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 3 byte(s) in 1 object(s) allocated from:
#0 0x7f0437de7628 in operator new[](unsigned long)
../../../../src/libsanitizer/asan/asan_new_delete.cpp:98
#1 0x556a5b56e1bc in main src/tmp.cpp:6
SUMMARY: AddressSanitizer: 3 byte(s) leaked in 1 allocation(s).
Am I doing something wrong?
