build: Allow setting flags from the environment

This adds `UK_ASFLAGS`, `UK_CFLAGS`, `UK_CXXFLAGS`, `UK_GOCFLAGS`, and `UK_LDFLAGS` for explicitly setting these build flags for Unikraft. For reference, see - https://github.com/torvalds/linux/blob/v6.4/Documentation/kbuild/kbuild.rst#environment-variables - https://github.com/torvalds/linux/blob/v6.4/Makefile#L1097-L1101 Signed-off-by: Martin Kröning <[email protected]> Reviewed-by: Stefan Jumarea <[email protected]> Reviewed-by: Marco Schlumpp <[email protected]> Approved-by: Simon Kuenzer <[email protected]> Tested-by: Unikraft CI <[email protected]> GitHub-Closes: #957
unikraft · Aug 4, 2023 · 73a18e2 · 73a18e2
1 parent 2f2ecc9
commit 73a18e2
Showing 1 changed file with 14 additions and 0 deletions.
diff --git a/Makefile b/Makefile
@@ -646,6  646,13 @@ CFLAGS		 = -DCC_VERSION=$(CC_VERSION)
 CXXFLAGS	 = -DCC_VERSION=$(CC_VERSION)
 GOCFLAGS	 = -DCC_VERSION=$(CC_VERSION)
 
 # Add user supplied flags as the last assignments
 ASFLAGS   = $(UK_ASFLAGS)
 CFLAGS    = $(UK_CFLAGS)
 CXXFLAGS  = $(UK_CXXFLAGS)
 GOCFLAGS  = $(UK_GOCFLAGS)
 LDFLAGS   = $(UK_LDFLAGS)
 
 # ensure $(BUILD_DIR)/kconfig, $(BUILD_DIR)/include and $(BUILD_DIR)/include/uk exists
 $(call mk_sub_build_dir,kconfig)
 $(call mk_sub_build_dir,include)
@@ -1100,6  1107,13 @@ help:
 	@echo '  L=[PATH]:[PATH]:..     - colon-separated list of paths to external libraries'
 	@echo '  P=[PATH]:[PATH]:..     - colon-separated list of paths to external platforms'
 	@echo ''
 	@echo 'Environment variables:'
 	@echo '  UK_ASFLAGS             - explicit Unikraft-specific additions to the assembler flags (the ASFLAGS variable is ignored)'
 	@echo '  UK_CFLAGS              - explicit Unikraft-specific additions to the C compiler flags (the CFLAGS variable is ignored)'
 	@echo '  UK_CXXFLAGS            - explicit Unikraft-specific additions to the C   compiler flags (the CXXFLAGS variable is ignored)'
 	@echo '  UK_GOCFLAGS            - explicit Unikraft-specific additions to the GO compiler flags (the GOCFLAGS variable is ignored)'
 	@echo '  UK_LDFLAGS             - explicit Unikraft-specific additions to the linker flags (the LDFLAGS variable is ignored)'
 	@echo ''
 	@echo 'Miscellaneous:'
 	@echo '  print-version          - print Unikraft version'
 	@echo '  print-libs             - print library names enabled for build'