https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85873
Bug ID: 85873
Summary: [8 regression] GCC omits array constant in .rodata
causing a segmentation fault.
Product: gcc
Version: 8.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: Kimon.Hoffmann at lawo dot com
Target Milestone: ---
Host: x86_64-linux-gnu
Target: x86_64-linux-gnu
Build: x86_64-linux-gnu
Created attachment 44162
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44162&action=edit
Preprocessed reproducer
GCC 8.1.0 (Debian 8.1.0-3) omits array constant in .rodata when optimizations
are enabled causing a segmentation fault. Previous versions (7.3.0 used for
reference) included the array definition as expected.
Test.cpp:
#include <cstdio>
#include <initializer_list>
constexpr std::initializer_list<char const*> retArray() noexcept
{
return std::initializer_list<char const*>{"Test 1", "Test 2", "Test
3"};
}
int main(int, char const* const*)
{
for (auto&& i : retArray())
{
std::puts(i);
}
return 0;
}
Compiled with:
gcc -std=c++17 -O1 -Wall -Wextra Test.cpp
Expected output:
Test 1
Test 2
Test 3
Actual output:
<SOME_GARBAGE>
Segmenation fault.
Notes:
* The preprocessed output has no functional differences between 7.3.0 and
8.1.0, which leads me to believe that this issue is not caused by changes to
the C++ standard library.
* Using objdump -s shows the .rodata section to be basically empty on
8.1.0, while containing the three strings on 7.3.0.
* No error messages or warnings are emitted during compilation.
* Building with -fsanitize=undefined does not result in any runtime
messages prior to the segmentation fault.
* Turning optimizations off yields the expected result.
* Changing the C++ standard to C++11 or C++14 does not affect the result.
Environment details:
g++ -v -std=c++17 -O1 -Wall -Wextra -save-temps Test.cpp
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/8/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 8.1.0-3'
--with-bugurl=file:///usr/share/doc/gcc-8/README.Bugs
--enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++ --prefix=/usr
--with-gcc-major-version-only --program-suffix=-8
--program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-vtable-verify --enable-libmpx --enable-plugin --enable-default-pie
--with-system-zlib --with-target-system-zlib --enable-objc-gc=auto
--enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64
--with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic
--enable-offload-targets=nvptx-none --without-cuda-driver
--enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=x86_64-linux-gnu
Thread model: posix
gcc version 8.1.0 (Debian 8.1.0-3)
COLLECT_GCC_OPTIONS='-v' '-std=c++17' '-O1' '-Wall' '-Wextra' '-save-temps'
'-shared-libgcc' '-mtune=generic' '-march=x86-64'
/usr/lib/gcc/x86_64-linux-gnu/8/cc1plus -E -quiet -v -imultiarch
x86_64-linux-gnu -D_GNU_SOURCE Test.cpp -mtune=generic -march=x86-64 -std=c++17
-Wall -Wextra -O1 -fpch-preprocess -o Test.ii
ignoring duplicate directory "/usr/include/x86_64-linux-gnu/c++/8"
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-linux-gnu/8/../../../../x86_64-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/include/c++/8
/usr/include/x86_64-linux-gnu/c++/8
/usr/include/c++/8/backward
/usr/lib/gcc/x86_64-linux-gnu/8/include
/usr/local/include
/usr/lib/gcc/x86_64-linux-gnu/8/include-fixed
/usr/include/x86_64-linux-gnu
/usr/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-std=c++17' '-O1' '-Wall' '-Wextra' '-save-temps'
'-shared-libgcc' '-mtune=generic' '-march=x86-64'
/usr/lib/gcc/x86_64-linux-gnu/8/cc1plus -fpreprocessed Test.ii -quiet
-dumpbase Test.cpp -mtune=generic -march=x86-64 -auxbase Test -O1 -Wall -Wextra
-std=c++17 -version -o Test.s
GNU C++17 (Debian 8.1.0-3) version 8.1.0 (x86_64-linux-gnu)
compiled by GNU C version 8.1.0, GMP version 6.1.2, MPFR version 4.0.1,
MPC version 1.1.0, isl version isl-0.19-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU C++17 (Debian 8.1.0-3) version 8.1.0 (x86_64-linux-gnu)
compiled by GNU C version 8.1.0, GMP version 6.1.2, MPFR version 4.0.1,
MPC version 1.1.0, isl version isl-0.19-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 5cdcbbb44235e5167a7c38e34cfe93e5
COLLECT_GCC_OPTIONS='-v' '-std=c++17' '-O1' '-Wall' '-Wextra' '-save-temps'
'-shared-libgcc' '-mtune=generic' '-march=x86-64'
as -v --64 -o Test.o Test.s
GNU assembler version 2.30 (x86_64-linux-gnu) using BFD version (GNU
Binutils for Debian) 2.30
COMPILER_PATH=/usr/lib/gcc/x86_64-linux-gnu/8/:/usr/lib/gcc/x86_64-linux-gnu/8/:/usr/lib/gcc/x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/8/:/usr/lib/gcc/x86_64-linux-gnu/
LIBRARY_PATH=/usr/lib/gcc/x86_64-linux-gnu/8/:/usr/lib/gcc/x86_64-linux-gnu/8/../../../x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/8/../../../../lib/:/lib/x86_64-linux-gnu/:/lib/../lib/:/usr/lib/x86_64-linux-gnu/:/usr/lib/../lib/:/usr/lib/gcc/x86_64-linux-gnu/8/../../../:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-v' '-std=c++17' '-O1' '-Wall' '-Wextra' '-save-temps'
'-shared-libgcc' '-mtune=generic' '-march=x86-64'
/usr/lib/gcc/x86_64-linux-gnu/8/collect2 -plugin
/usr/lib/gcc/x86_64-linux-gnu/8/liblto_plugin.so
-plugin-opt=/usr/lib/gcc/x86_64-linux-gnu/8/lto-wrapper
-plugin-opt=-fresolution=Test.res -plugin-opt=-pass-through=-lgcc_s
-plugin-opt=-pass-through=-lgcc -plugin-opt=-pass-through=-lc
-plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lgcc --sysroot=/
--build-id --eh-frame-hdr -m elf_x86_64 --hash-style=gnu -dynamic-linker
/lib64/ld-linux-x86-64.so.2 -pie
/usr/lib/gcc/x86_64-linux-gnu/8/../../../x86_64-linux-gnu/Scrt1.o
/usr/lib/gcc/x86_64-linux-gnu/8/../../../x86_64-linux-gnu/crti.o
/usr/lib/gcc/x86_64-linux-gnu/8/crtbeginS.o -L/usr/lib/gcc/x86_64-linux-gnu/8
-L/usr/lib/gcc/x86_64-linux-gnu/8/../../../x86_64-linux-gnu
-L/usr/lib/gcc/x86_64-linux-gnu/8/../../../../lib -L/lib/x86_64-linux-gnu
-L/lib/../lib -L/usr/lib/x86_64-linux-gnu -L/usr/lib/../lib
-L/usr/lib/gcc/x86_64-linux-gnu/8/../../.. Test.o -lstdc++ -lm -lgcc_s -lgcc
-lc -lgcc_s -lgcc /usr/lib/gcc/x86_64-linux-gnu/8/crtendS.o
/usr/lib/gcc/x86_64-linux-gnu/8/../../../x86_64-linux-gnu/crtn.o
COLLECT_GCC_OPTIONS='-v' '-std=c++17' '-O1' '-Wall' '-Wextra' '-save-temps'
'-shared-libgcc' '-mtune=generic' '-march=x86-64'
)
