https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112372
Bug ID: 112372
Summary: GCC omits function location in DWARF at higher
optimisation levels
Product: gcc
Version: 13.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: debug
Assignee: unassigned at gcc dot gnu.org
Reporter: gprocida at google dot com
Target Milestone: ---
Source:
void x(signed char c) { (void) c; }
void y(char c) { (void) c; }
void z(unsigned char c) { (void) c; } // not needed
GCC versions tested: 11.4.0, 12.3.0, 13.2.0
DWARF versions tested: 3, 4, 5
Optimisation levels tests: 0, 1, g (all good); 2, 3, fast, s (all bad)
At lower levels of optimisation, the 3 functions are described with
straightforward DIEs.
At higher levels of optimisation, they are... a mess.
x has abstract origin
y is missing location (PC)
z looks normal
The missing location means that binary analysis tools, like libabigail, cannot
associated the symbol y with its type.
FWIW, Clang does not have this issue.
Remove x: issue disappears.
Remove y: issue disappears.
Remove z: issue persists.
gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-linux-gnu/13/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 13.2.0-4'
--with-bugurl=file:///usr/share/doc/gcc-13/README.Bugs
--enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++,m2 --prefix=/usr
--with-gcc-major-version-only --program-suffix=-13
--program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
--libexecdir=/usr/libexec --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --enable-bootstrap --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-vtable-verify --enable-plugin --enable-default-pie --with-system-zlib
--enable-libphobos-checking=release --with-target-system-zlib=auto
--enable-objc-gc=auto --enable-multiarch --disable-werror --enable-cet
--with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32
--enable-multilib --with-tune=generic
--enable-offload-targets=nvptx-none=/build/gcc-13-oyarai/gcc-13-13.2.0/debian/tmp-nvptx/usr,amdgcn-amdhsa=/build/gcc-13-oyarai/gcc-13-13.2.0/debian/tmp-gcn/usr
--enable-offload-defaulted --without-cuda-driver --enable-checking=release
--build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
--with-build-config=bootstrap-lto-lean --enable-link-serialization=28
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 13.2.0 (Debian 13.2.0-4)
gcc -Wall -Wextra -o x.o -O2 -c -g x.c
