https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115943
Bug ID: 115943 Summary: g++ generates contradictory line table entries Product: gcc Version: 14.1.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: debug Assignee: unassigned at gcc dot gnu.org Reporter: blarsen at redhat dot com Target Milestone: --- Created attachment 58670 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58670&action=edit minimal cpp code that reproduces the issue The issue: GCC is generating some superfluous and many contradicting entries to the line table of the binary. Here's a snippet of the line table as printed by GDB: INDEX LINE REL-ADDRESS UNREL-ADDRESS IS-STMT 0 7 0x0000000000401126 0x0000000000401126 Y 1 8 0x0000000000401126 0x0000000000401126 Y 2 8 0x0000000000401126 0x0000000000401126 All these entries refer to the same instruction, but 0 and 1 say that instruction is a statement, while entry 2 says it isn't be (contradictory). Entry 0 says the instruction belongs to the line declaring the function, while 1 and 2 say it belongs to the first line in the function, which is quite confusing and redundant. Entry 1 is set via a Special Opcode, and there are a few cases where a line table entry is set through a special opcode, then its is_stmt status is changed and it is copied again. It almost looks as though gcc isn't considering special opcodes as though they cause a DW_LNS_copy. command line: g++ -fPIC -Og -g gcc_reproducer.cpp GCC information: gcc version 14.1.1 20240701 (Red Hat 14.1.1-7) (GCC) Configured with: ../configure --enable-bootstrap --enable-languages=c,c++,fortran,objc,obj-c++,ada,go,d,m2,lto --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-shared --enable-threads=posix --enable-checking=release --enable-multilib --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --with-gcc-major-version-only --enable-libstdcxx-backtrace --with-libstdcxx-zoneinfo=/usr/share/zoneinfo --with-linker-hash-style=gnu --enable-plugin --enable-initfini-array --with-isl=/builddir/build/BUILD/gcc-14.1.1-20240701/obj-x86_64-redhat-linux/isl-install --enable-offload-targets=nvptx-none,amdgcn-amdhsa --enable-offload-defaulted --without-cuda-driver --enable-gnu-indirect-function --enable-cet --with-tune=generic --with-arch_32=i686 --build=x86_64-redhat-linux --with-build-config=bootstrap-lto --enable-link-serialization=1