I have attempted to upgrade the toolchain on a project for a Cortex-M0+ that requires LTO to fit in flash. The project has built just fine up until now, but after upgrading to the latest 10.3-2021.07 version, the linking stage fails. Here's what the output looks like:
/tmp/cczekWsc.s: Assembler messages: /tmp/cczekWsc.s:2262: Warning: ignoring changed section attributes for .data /tmp/cczekWsc.s:2272: Warning: dwarf line number information for .data ignored /tmp/cczekWsc.s:2277: Warning: dwarf line number information for .data ignored (repeated hundreds of times) /tmp/cczekWsc.s:61406: Error: leb128 operand is an undefined symbol: .LVU708 /tmp/cczekWsc.s:61407: Error: leb128 operand is an undefined symbol: .LVU708 /tmp/cczekWsc.s:61425: Error: leb128 operand is an undefined symbol: .LVU730 (also repeated hundred plus of times)
Has anyone seen anything like this before? I tried searching for help on this, but came up blank. I'm unsure about how I should even start approaching this as I was unable to even keep the temporary assembler output from the LTO process.
This seems related to this bugreport: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103698
The combination of placing functions in the .data section (typically flash operations which by nature can not run through XIP), LTO and generating debug information by passing -g to the compiler leads to confusion somewhere down the toolchain here. I guess the suspected culprit is probably the binutils assembler.
My project builds just fine if I remove '-g' from the CFLAGS.
I tried to use LTO in a project with a size limitation.It turned out that the issues disappeared when I downgraded the toolchain to version 9.2.1.I am not sure if the problems are related.
[100%] Linking CXX executable C:\.....\Build\release\......elf C:\Users\.....\AppData\Local\Temp\ccc05Sxb.s: Assembler messages: C:\Users\.....\AppData\Local\Temp\ccc05Sxb.s:3544: Error: branch out of range lto-wrapper.exe: fatal error: C:\.....\bin\arm-none-eabi-g++.exe returned 1 exit status compilation terminated. c:/...../arm-none-eabi/bin/ld.exe: error: lto-wrapper failed collect2.exe: error: ld returned 1 exit status mingw32-make.exe[2]: *** [CMakeFiles\......elf.dir\build.make:1552: C:/...../Build/release/......elf] Error 1 mingw32-make.exe[1]: *** [CMakeFiles\Makefile2:83: CMakeFiles/......elf.dir/all] Error 2 mingw32-make.exe: *** [Makefile:90: all] Error 2 The terminal process "C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe -Command cmake --build . -j" terminated with exit code: 1.