Hi! In one of my embedded projects I have an option to enable LTO. This was working more or less fine for GCC 6 and GCC 7, however for GCC 8.1.0 (and binutils 2.30) - with the same set of options - I see something like this
-- >8 -- >8 -- >8 -- >8 -- >8 -- >8 -- >8 -- >8 -- >8 -- >8 -- $ arm-none-eabi-g++ -Wall -Wextra -Wshadow -std=gnu++11 -mcpu=cortex-m4 -mthumb -mfloat-abi=hard -mfpu=fpv4-sp-d16 -g -ggdb3 -O2 -flto -ffat- lto-objects -fno-use-cxa-atexit -ffunction-sections -fdata-sections -fno-rtti -fno-exceptions ... [include paths] ... -MD -MP -c test/TestCase.cpp -o output/test/TestCase.o $ arm-none-eabi-g++ -mcpu=cortex-m4 -mthumb -mfloat-abi=hard -mfpu=fpv4-sp-d16 -g -O2 -flto -fuse-linker-plugin -Wl,- Map=output/test/distortosTest.map,--cref,--gc-sections -Toutput/ST_STM32F4DISCOVERY.preprocessed.ld ... [a lot of objects] ... -Wl,--whole-archive -l:output/libdistortos.a -Wl,--no-whole-archive -o output/test/distortosTest.elf $ arm-none-eabi-objdump --demangle -S output/test/distortosTest.elf > output/test/distortosTest.lss arm-none-eabi-objdump: Dwarf Error: Could not find abbrev number 167. arm-none-eabi-objdump: Dwarf Error: found dwarf version '37', this reader only handles version 2, 3, 4 and 5 information. arm-none-eabi-objdump: Dwarf Error: found dwarf version '6144', this reader only handles version 2, 3, 4 and 5 information. arm-none-eabi-objdump: Dwarf Error: found dwarf version '4864', this reader only handles version 2, 3, 4 and 5 information. ... ... (a lot more) ... -- >8 -- >8 -- >8 -- >8 -- >8 -- >8 -- >8 -- >8 -- >8 -- >8 -- As you see, the errors apear only when I try to generate an assembly dump. I'm not sure whether the problem is in GCC or in objdump, but when I have an .elf file produced (with the same options) by gcc 7.3.0, then this new version of objdump doesn't produce any errors. What is also interesting is that the errors are not fatal - the exit code of the process is 0. What is also interesing is that this problem doesn't appear in a trivial test case, so I suspect this is something more subtle. I did not try to narrow it down into a shareable test case, but if you have no hints then maybe I'll try to do that. Any ideas what may be the problem here? Especially do you know whether I should be asking this question here or maybe on binutils mailing list? Thanks in advance! Regards, FCh
