Public bug reported: The rules files specifies the following optimization flasg for the regular and nano buiLds respectively:
CFLAGS := CFLAGS="-g -O2 -ffunction-sections -fdata-sections" CFLAGS_NANO := CFLAGS="-g -Os -ffunction-sections -fdata-sections -fshort-wchar" (https://git.launchpad.net/ubuntu/+source/newlib/tree/debian/rules#n21) However, these flags are not applied to the actual target files, only to host tool builds, it seems. This can be confirmed by examining the resulting libc: $ objdump -t /usr/lib/arm-none-eabi/newlib/thumb/v7/nofp/libc.a | grep ' printf' 00000000 l df *ABS* 00000000 printf.c 00000021 g F .text 00000028 printf Note that printf is placed in the .text section (along with all other functions) - this would not be the case had -ffunction-sections been passed during build, in that case printif would be placed into ist own unique .text.printf section. This also means that -Os is not applied to nano builds. To pass flags to the target build one needs to use CFLAGS_FOR_TARGET instead. CFLAGS := CFLAGS= CFLAGS_FOR_TARGET="-g -O2 -ffunction-sections -fdata-sections" CFLAGS_NANO := CFLAGS= CFLAGS_FOR_TARGET="-g -Os -ffunction-sections -fdata-sections -fshort-wchar" Note that CFLAGS also needs to be set, even if to an empty value. ** Affects: newlib (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2086618 Title: Compiler optimization flags are not applied correctly To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/newlib/+bug/2086618/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
