config/mh-darwin

   1 # The -mdynamic-no-pic ensures that the compiler executable is built without
   2 # position-independent-code -- the usual default on Darwin. This speeds compiles
   3 # by 8-20% (measurements made against GCC-11).
   4 # However, we cannot add it unless the bootstrap compiler supports
   5 # -mno-dynamic-no-pic to undo it, since libiberty, at least, needs this.
   6
   7 # We use Werror, since some versions of clang report unknown command line flags
   8 # as a warning only.
   9
  10 # We only need to determine this for the host tool used to build stage1 (or a
  11 # non-bootstrapped compiler), later stages will be built by GCC which supports
  12 # the required flags.
  13
  14 # We cannot use mdynamic-no-pic when building shared host resources.
  15
  16 ifeq (${host_shared},no)
  17 BOOTSTRAP_TOOL_CAN_USE_MDYNAMIC_NO_PIC := $(shell \
  18   $(CC) -S -xc /dev/null -o /dev/null -Werror -mno-dynamic-no-pic 2>/dev/null \
  19   && echo true)
  20 else
  21 BOOTSTRAP_TOOL_CAN_USE_MDYNAMIC_NO_PIC := false
  22 endif
  23
  24 @if gcc-bootstrap
  25 ifeq (${BOOTSTRAP_TOOL_CAN_USE_MDYNAMIC_NO_PIC},true)
  26 STAGE1_CFLAGS += -mdynamic-no-pic
  27 else
  28 STAGE1_CFLAGS += -fPIC
  29 endif
  30 ifeq (${host_shared},no)
  31 # Add -mdynamic-no-pic to later stages when we know it is built with GCC.
  32 BOOT_CFLAGS += -mdynamic-no-pic
  33 endif
  34 @endif gcc-bootstrap
  35
  36 @unless gcc-bootstrap
  37 ifeq (${BOOTSTRAP_TOOL_CAN_USE_MDYNAMIC_NO_PIC},true)
  38 # FIXME: we should also enable this for cross and non-bootstrap builds but
  39 # that needs amendment to libcc1.
  40 # CFLAGS += -mdynamic-no-pic
  41 # CXXFLAGS += -mdynamic-no-pic
  42 else
  43 CFLAGS += -fPIC
  44 CXXFLAGS += -fPIC
  45 endif
  46 @endunless gcc-bootstrap