On Thu, Aug 03, 2017 at 06:27:02AM +0200, Heinrich Schuchardt wrote: > Hello Tom, > > for the UEFI implementation of U-Boot it would make defining string > constants much easier using the following C 2011 notation: > > u16 *foo = u"My lovely string"; > > Do you see any reason forcing us not to use features of C 2011? > > In /Makefile I found the following: > > ifeq ($(HOSTOS),cygwin) > HOSTCFLAGS += -ansi > endif > > # > # Xtensa linker script cannot be preprocessed with -ansi because of > # preprocessor operations on strings that don't make C identifiers. > # > ifeq ($(CONFIG_XTENSA),) > LDPPFLAGS += -ansi > endif > > # Create a file containing the configuration options the image was built > with > quiet_cmd_cpp_cfg = CFG $@ > cmd_cpp_cfg = $(CPP) -Wp,-MD,$(depfile) $(cpp_flags) $(LDPPFLAGS) -ansi \ > -DDO_DEPS_ONLY -D__ASSEMBLY__ -x assembler-with-cpp -P -dM -E -o $@ $< > > The GCC documentation teaches: > -ansi: In C mode, this is equivalent to -std=c90. In C++ mode, it is > equivalent to -std=c++98. > > When I am building for arm64 I find these options actually used: > > aarch64-linux-gnu-gcc -Wp,-MD,common/.cli_hush.o.d -nostdinc -isystem > /usr/lib/gcc-cross/aarch64-linux-gnu/6/include -Iinclude > -I./arch/arm/include -include ./include/linux/kconfig.h -D__KERNEL__ > -D__UBOOT__ -Wall -Wstrict-prototypes -Wno-format-security -fno-builtin > -ffreestanding -Os -fno-stack-protector -fno-delete-null-pointer-checks > -g -fstack-usage -Wno-format-nonliteral -Werror=date-time -D__ARM__ > -fno-pic -mstrict-align -ffunction-sections -fdata-sections -fno-common > -ffixed-r9 -fno-common -ffixed-x18 -pipe -march=armv8-a > -D__LINUX_ARM_ARCH__=8 -I./arch/arm/mach-meson/include > -D"KBUILD_STR(s)=#s" -D"KBUILD_BASENAME=KBUILD_STR(cli_hush)" > -D"KBUILD_MODNAME=KBUILD_STR(cli_hush)" -c -o common/cli_hush.o > common/cli_hush.c > > My impression is that: > > We have variables in /Makefile that are not used for anything: > LDPPFLAGS, cmd_cpp_cfg, cmd_cpp_lds. > > All lines refering to these variables should be removed. > Cf. https://lists.denx.de/pipermail/u-boot/2016-September/267177.html
OK. Drop 'em, throw travis-ci at it and see what, if anything, blows up. > We force C90 on cygwin to compile the host code but not for the actual > U-Boot code. Probably a remnant from a distant past. > > So nothing should stop us from using C2011 in U-Boot. What's the minimum gcc (and llvm) version we need to use here? Thanks! -- Tom
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