csu/Makefile

   1 # Makefile for csu code for GNU C library.
   2 # Copyright (C) 1995-2017 Free Software Foundation, Inc.
   3 # This file is part of the GNU C Library.
   4
   5 # The GNU C Library is free software; you can redistribute it and/or
   6 # modify it under the terms of the GNU Lesser General Public
   7 # License as published by the Free Software Foundation; either
   8 # version 2.1 of the License, or (at your option) any later version.
   9
  10 # The GNU C Library is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 # Lesser General Public License for more details.
  14
  15 # You should have received a copy of the GNU Lesser General Public
  16 # License along with the GNU C Library; if not, see
  17 # <http://www.gnu.org/licenses/>.
  18
  19 # This directory contains the C startup code (that which calls main).  This
  20 # consists of the startfile, built from start.c and installed as crt0.o
  21 # (traditionally) or crt1.o (for ELF).  In ELF we also install crti.o and
  22 # crtn.o, special "initializer" and "finalizer" files used in the link
  23 # to make the .init and .fini sections work right.
  24
  25 subdir := csu
  26
  27 include ../Makeconfig
  28
  29 routines = init-first libc-start $(libc-init) sysdep version check_fds \
  30            libc-tls elf-init dso_handle
  31 aux      = errno
  32 elide-routines.os = libc-tls
  33 static-only-routines = elf-init
  34 csu-dummies = $(filter-out $(start-installed-name),crt1.o Mcrt1.o)
  35 extra-objs = start.o \
  36              $(start-installed-name) g$(start-installed-name) $(csu-dummies) \
  37              S$(start-installed-name)
  38 omit-deps = $(patsubst %.o,%,$(start-installed-name) g$(start-installed-name) \
  39                              b$(start-installed-name) $(csu-dummies) \
  40                              S$(start-installed-name))
  41 install-lib = $(start-installed-name) g$(start-installed-name) $(csu-dummies)
  42
  43 # No tests are allowed in the csu/ subdirectory because the startup
  44 # code is compiled with special flags.
  45 tests =
  46
  47 CFLAGS-.o += $(no-stack-protector)
  48 CFLAGS-.op += $(no-stack-protector)
  49 CFLAGS-.os += $(no-stack-protector)
  50
  51 ifeq (yes,$(build-shared))
  52 extra-objs += S$(start-installed-name) gmon-start.os
  53 ifneq ($(start-installed-name),$(static-start-installed-name))
  54 extra-objs += gmon-start.o
  55 endif
  56 install-lib += S$(start-installed-name)
  57 generated += start.os
  58 else
  59 extra-objs += gmon-start.o
  60 endif
  61
  62 ifneq ($(start-installed-name),$(static-start-installed-name))
  63 extra-objs += $(static-start-installed-name) g$(static-start-installed-name)
  64 omit-deps += $(patsubst %.o,%,$(static-start-installed-name) \
  65                              g$(static-start-installed-name))
  66 install-lib += $(static-start-installed-name) g$(static-start-installed-name)
  67 endif
  68
  69 before-compile += $(objpfx)abi-tag.h
  70 generated += abi-tag.h
  71
  72 # These are the special initializer/finalizer files.  They are always the
  73 # first and last file in the link.  crti.o ... crtn.o define the global
  74 # "functions" _init and _fini to run the .init and .fini sections.
  75 crtstuff = crti crtn
  76
  77 install-lib += $(crtstuff:=.o)
  78 extra-objs += $(crtstuff:=.o)
  79
  80 extra-objs += abi-note.o init.o
  81 asm-CPPFLAGS += -I$(objpfx).
  82
  83 # Enable unwinding so backtrace unwinds to __libc_start_main
  84 CFLAGS-libc-start.c += -funwind-tables
  85
  86 include ../Rules
  87
  88 # Make these in the lib pass so they're available in time to link things with.
  89 subdir_lib: $(extra-objs:%=$(objpfx)%)
  90
  91 define link-relocatable
  92 $(CC) -nostdlib -nostartfiles -r -o $@ $^
  93 endef
  94
  95 ifndef start-installed-name-rule
  96 # We link the ELF startfile along with a SHT_NOTE section indicating
  97 # the kernel ABI the binaries linked with this library will require.
  98 $(objpfx)$(start-installed-name): $(objpfx)start.o $(objpfx)abi-note.o \
  99                                   $(objpfx)init.o
 100         $(link-relocatable)
 101 $(objpfx)S$(start-installed-name): $(objpfx)start.os $(objpfx)abi-note.o \
 102                                   $(objpfx)init.o
 103         $(link-relocatable)
 104 endif
 105
 106 # The profiling startfile is made by linking together the normal
 107 # startfile with gmon-start.o, which defines a constructor function
 108 # to turn on profiling code at startup.
 109 ifeq (yes,$(build-shared))
 110 $(objpfx)g$(start-installed-name): \
 111   $(objpfx)g%: $(objpfx)S% $(objpfx)gmon-start.os
 112         $(link-relocatable)
 113 ifneq ($(start-installed-name),$(static-start-installed-name))
 114 $(objpfx)g$(static-start-installed-name): \
 115   $(objpfx)g%: $(objpfx)% $(objpfx)gmon-start.o
 116         $(link-relocatable)
 117 endif
 118 else
 119 $(addprefix $(objpfx),$(sort g$(start-installed-name) \
 120                              g$(static-start-installed-name))): \
 121   $(objpfx)g%: $(objpfx)% $(objpfx)gmon-start.o
 122         $(link-relocatable)
 123 endif
 124
 125 # These extra files are sometimes expected by system standard linking
 126 # procedures, but we have nothing for them to do.  So compile empty files.
 127 $(addprefix $(objpfx),$(filter-out $(start-installed-name), $(csu-dummies))):\
 128   $(before-compile)
 129         $(COMPILE.c) -o $@ -x c /dev/null
 130
 131 # These headers are used by the startup code.
 132 $(objpfx)abi-tag.h: $(..)abi-tags
 133         $(make-target-directory)
 134         rm -f $@.new
 135         sed -e 's/#.*$$//' -e '/^[      ]*$$/d' $< | \
 136         while read conf tagos tagver; do \
 137           test `expr '$(config-machine)-$(config-vendor)-$(config-os)' \
 138                      : "$$conf"` != 0 || continue; \
 139           ( echo "$$tagos" | \
 140             sed -e 's/[^0-9xXa-fA-F     ]//' \
 141                 -e 's/^/#define __ABI_TAG_OS /'; \
 142             echo "#ifndef __ABI_TAG_VERSION"; \
 143             echo "$$tagver" | \
 144             sed -e 's/[^0-9xXa-fA-F]/ /g' -e 's/ *$$//' \
 145               -e 's/ /,/g' -e 's/^/# define __ABI_TAG_VERSION /'; \
 146             echo "#endif" ) > $@.new; \
 147         done
 148         if test -r $@.new; then mv -f $@.new $@; \
 149         else echo >&2 'This configuration not matched in $<'; exit 1; fi