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RIOT/makefiles/libc/newlib.mk 3.84 KB
a752c7ab   elopes   add first test an...
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  ifneq (,$(filter newlib_nano,$(USEMODULE)))
    # Test if nano.specs is available
    ifeq ($(shell $(LINK) -specs=nano.specs -E - 2>/dev/null >/dev/null </dev/null ; echo $$?),0)
      USE_NEWLIB_NANO = 1
      ifeq ($(shell echo "int main(){} void _exit(int n) {(void)n;while(1);}" | LC_ALL=C $(CC) -xc - -o /dev/null -lc -specs=nano.specs -Wall -Wextra -pedantic 2>&1 | grep -q "use of wchar_t values across objects may fail" ; echo $$?),0)
          CFLAGS += -fshort-wchar
          LINKFLAGS += -Wl,--no-wchar-size-warning
      endif
    endif
  endif
  
  ifeq (1,$(USE_NEWLIB_NANO))
    export LINKFLAGS += -specs=nano.specs
  endif
  
  ifeq ($(TARGET_ARCH),mips-mti-elf)
   export LINKFLAGS += -lc
  else
   export LINKFLAGS += -lc -lnosys
  endif
  
  # Search for Newlib include directories
  
  # Since Clang is not installed as a separate instance for each crossdev target
  # we need to tell it where to look for platform specific includes (Newlib
  # headers instead of Linux/Glibc headers.)
  # On GCC this is done when building the cross compiler toolchain so we do not
  # actually need to specify the include paths for system includes.
  # Ubuntu gcc-arm-embedded toolchain (https://launchpad.net/gcc-arm-embedded)
  # places newlib headers in several places, but the primary source seem to be
  # /etc/alternatives/gcc-arm-none-eabi-include
  # Gentoo Linux crossdev place the newlib headers in /usr/arm-none-eabi/include
  # Arch Linux also place the newlib headers in /usr/arm-none-eabi/include
  # Ubuntu seem to put a copy of the newlib headers in the same place as
  # Gentoo crossdev, but we prefer to look at /etc/alternatives first.
  # On OSX, newlib includes are possibly located in
  # /usr/local/opt/arm-none-eabi*/arm-none-eabi/include or /usr/local/opt/gcc-arm/arm-none-eabi/include
  NEWLIB_INCLUDE_PATTERNS ?= \
    /etc/alternatives/gcc-$(TARGET_ARCH)-include \
    /usr/$(TARGET_ARCH)/include \
    /usr/local/opt/$(TARGET_ARCH)*/$(TARGET_ARCH)/include \
    /usr/local/opt/gcc-*/$(TARGET_ARCH)/include \
    #
  # Use the wildcard Makefile function to search for existing directories matching
  # the patterns above. We use the -isystem gcc/clang argument to add the include
  # directories as system include directories, which means they will not be
  # searched until after all the project specific include directories (-I/path)
  NEWLIB_INCLUDE_DIR ?= $(firstword $(wildcard $(NEWLIB_INCLUDE_PATTERNS)))
  
  # If nothing was found we will try to fall back to searching for a cross-gcc in
  # the current PATH and use a relative path for the includes
  ifeq (,$(NEWLIB_INCLUDE_DIR))
    NEWLIB_INCLUDE_DIR := $(abspath $(wildcard $(dir $(shell command -v $(PREFIX)gcc 2>/dev/null))/../$(TARGET_ARCH)/include))
  endif
  
  ifeq ($(TOOLCHAIN),llvm)
    # A cross GCC already knows the target libc include path (build-in at compile time)
    # but Clang, when cross-compiling, needs to be told where to find the headers
    # for the system being built.
    # We also add -nostdinc to avoid including the host system headers by mistake
    # in case some header is missing from the cross tool chain
    NEWLIB_INCLUDES := -isystem $(NEWLIB_INCLUDE_DIR) -nostdinc
    NEWLIB_INCLUDES += $(addprefix -isystem ,$(abspath $(wildcard $(dir $(NEWLIB_INCLUDE_DIR))/usr/include)))
  endif
  
  ifeq (1,$(USE_NEWLIB_NANO))
    NEWLIB_NANO_INCLUDE_DIR ?= $(NEWLIB_INCLUDE_DIR)/newlib-nano
    # newlib-nano overrides newlib.h and its include dir should therefore go before
    # the regular system include dirs.
    INCLUDES := -isystem $(NEWLIB_NANO_INCLUDE_DIR) $(INCLUDES)
  endif
  
  # Newlib includes should go before GCC includes. This is especially important
  # when using Clang, because Clang will yield compilation errors on some GCC-
  # bundled headers. Clang compatible versions of those headers are already
  # provided by Newlib, so placing this directory first will eliminate those problems.
  # The above problem was observed with LLVM 3.9.1 when building against GCC 6.3.0 headers.
  export INCLUDES := $(NEWLIB_INCLUDES) $(INCLUDES)