Reduce the statically linked startup code [BZ #23323]

[thirdparty/glibc.git] / csu / Makefile

diff --git a/csu/Makefile b/csu/Makefile
index 490d0b0f3b63318381e59fc35038801f682d20a2..e587434be86c8bcb66c9166a6780c8a2a7e71a58 100644 (file)
--- a/csu/Makefile
+++ b/csu/Makefile
@@ -1,5 +1,5 @@
 # Makefile for csu code for GNU C library.
-# Copyright (C) 1995-2017 Free Software Foundation, Inc.
+# Copyright (C) 1995-2021 Free Software Foundation, Inc.
 # This file is part of the GNU C Library.
 
 # The GNU C Library is free software; you can redistribute it and/or
@@ -14,7 +14,7 @@
 
 # You should have received a copy of the GNU Lesser General Public
 # License along with the GNU C Library; if not, see
-# <http://www.gnu.org/licenses/>.
+# <https://www.gnu.org/licenses/>.
 
 # This directory contains the C startup code (that which calls main).  This
 # consists of the startfile, built from start.c and installed as crt0.o
@@ -27,20 +27,19 @@ subdir := csu
 include ../Makeconfig
 
 routines = init-first libc-start $(libc-init) sysdep version check_fds \
-          libc-tls elf-init dso_handle
+          libc-tls dso_handle
 aux     = errno
 elide-routines.os = libc-tls
-static-only-routines = elf-init
 csu-dummies = $(filter-out $(start-installed-name),crt1.o Mcrt1.o)
 extra-objs = start.o \
             $(start-installed-name) g$(start-installed-name) $(csu-dummies) \
             S$(start-installed-name)
 omit-deps = $(patsubst %.o,%,$(start-installed-name) g$(start-installed-name) \
                             b$(start-installed-name) $(csu-dummies) \
-                            S$(start-installed-name))
+                            S$(start-installed-name) \
+                            r$(start-installed-name) \
+                            gr$(start-installed-name))
 install-lib = $(start-installed-name) g$(start-installed-name) $(csu-dummies)
-generated += version-info.h
-before-compile += $(objpfx)version-info.h
 
 # No tests are allowed in the csu/ subdirectory because the startup
 # code is compiled with special flags.
@@ -50,6 +49,15 @@ CFLAGS-.o += $(no-stack-protector)
 CFLAGS-.op += $(no-stack-protector)
 CFLAGS-.os += $(no-stack-protector)
 
+# Dummy object not actually used for anything.  It is linked into
+# crt1.o nevertheless, which in turn is statically linked into
+# applications, so that build flags matter.
+# See <https://sourceware.org/ml/libc-alpha/2018-07/msg00101.html>.
+# NB: Using $(stack-protector) in this way causes a wrong definition
+# STACK_PROTECTOR_LEVEL due to the preceding $(no-stack-protector),
+# but it does not matter for this source file.
+CFLAGS-static-reloc.os += $(stack-protector)
+
 ifeq (yes,$(build-shared))
 extra-objs += S$(start-installed-name) gmon-start.os
 ifneq ($(start-installed-name),$(static-start-installed-name))
@@ -62,10 +70,17 @@ extra-objs += gmon-start.o
 endif
 
 ifneq ($(start-installed-name),$(static-start-installed-name))
+# FIXME: Only Hurd defines static-start-installed-name.  Hurd needs to
+# provide special rules to support static PIE.
 extra-objs += $(static-start-installed-name) g$(static-start-installed-name)
 omit-deps += $(patsubst %.o,%,$(static-start-installed-name) \
                             g$(static-start-installed-name))
 install-lib += $(static-start-installed-name) g$(static-start-installed-name)
+else
+ifeq (yes,$(enable-static-pie))
+extra-objs += r$(start-installed-name) gr$(start-installed-name)
+install-lib += r$(start-installed-name) gr$(start-installed-name)
+endif
 endif
 
 before-compile += $(objpfx)abi-tag.h
@@ -79,7 +94,15 @@ crtstuff = crti crtn
 install-lib += $(crtstuff:=.o)
 extra-objs += $(crtstuff:=.o)
 
-extra-objs += abi-note.o init.o
+ifneq ($(multidir),.)
+multilib-extra-objs = $(addprefix $(multidir)/, $(install-lib))
+extra-objs += $(multilib-extra-objs)
+endif
+
+extra-objs += abi-note.o init.o static-reloc.o
+ifeq (yes,$(build-shared))
+extra-objs += static-reloc.os
+endif
 asm-CPPFLAGS += -I$(objpfx).
 
 # Enable unwinding so backtrace unwinds to __libc_start_main
@@ -98,6 +121,9 @@ ifndef start-installed-name-rule
 # We link the ELF startfile along with a SHT_NOTE section indicating
 # the kernel ABI the binaries linked with this library will require.
 $(objpfx)$(start-installed-name): $(objpfx)start.o $(objpfx)abi-note.o \
+                                 $(objpfx)init.o $(objpfx)static-reloc.o
+       $(link-relocatable)
+$(objpfx)r$(start-installed-name): $(objpfx)start.o $(objpfx)abi-note.o \
                                  $(objpfx)init.o
        $(link-relocatable)
 $(objpfx)S$(start-installed-name): $(objpfx)start.os $(objpfx)abi-note.o \
@@ -110,7 +136,10 @@ endif
 # to turn on profiling code at startup.
 ifeq (yes,$(build-shared))
 $(objpfx)g$(start-installed-name): \
-  $(objpfx)g%: $(objpfx)S% $(objpfx)gmon-start.os
+  $(objpfx)g%: $(objpfx)S% $(objpfx)gmon-start.os $(objpfx)static-reloc.os
+       $(link-relocatable)
+$(objpfx)gr$(start-installed-name): \
+  $(objpfx)gr%: $(objpfx)r% $(objpfx)gmon-start.o
        $(link-relocatable)
 ifneq ($(start-installed-name),$(static-start-installed-name))
 $(objpfx)g$(static-start-installed-name): \
@@ -150,15 +179,7 @@ $(objpfx)abi-tag.h: $(..)abi-tags
        if test -r $@.new; then mv -f $@.new $@; \
        else echo >&2 'This configuration not matched in $<'; exit 1; fi
 
-all-Banner-files = $(wildcard $(addsuffix /Banner,\
-                                         $(sort $(subdir-srcdirs) \
-                                                $(sysdeps-srcdirs))))
-$(objpfx)version-info.h: $(common-objpfx)config.make $(all-Banner-files)
-       $(make-target-directory)
-       (files="$(all-Banner-files)";                           \
-        if test -n "$$files"; then                             \
-          printf '"Available extensions:\\n"\n';               \
-          sed -e '/^#/d' -e 's/^[[:space:]]*/  /'              \
-              -e 's/^\(.*\)$$/\"\1\\n\"/' $$files;             \
-        fi) > $@T
-       mv -f $@T $@
+ifneq ($(multidir),.)
+$(addprefix $(objpfx)$(multidir)/, $(install-lib)): $(addprefix $(objpfx), $(install-lib))
+       $(make-link-multidir)
+endif