Richard Sandiford writes: add support for init/fini arrays in shared flat libraries

Makefile.in

@@ -246,6 +246,15 @@ ifeq ($(DOPIC),y)
 	fi
 endif
 endif
+ifeq ($(HAVE_SHARED_FLAT),y)
+	for file in lib/lib*.gdb; do \
+		if test -f $$file; then \
+			$(INSTALL) -m 755 $$file $(PREFIX)$(DEVEL_PREFIX)lib; \
+			$(INSTALL) -m 755 `echo $$file | sed 's/\.gdb$$//'` \
+			  $(PREFIX)$(DEVEL_PREFIX)lib; \
+		fi; \
+	done
+endif
 
 # Installs run-time libraries
 install_runtime:

Makerules

@@ -11,6 +11,9 @@ libs: $(lib-so-y) $(lib-a-y)
 $(lib-so-y): $(interp)
 else
 .LIBPATTERNS: "lib%.a"
+ifeq ($(HAVE_SHARED_FLAT),y)
+libs: $(lib-gdb-y)
+endif
 libs: $(lib-a-y)
 endif
 objs: all_objs
@@ -131,6 +134,29 @@ define link.so
 	$(Q)$(LN) -sf $(1) $@
 endef
 
+# CRT files needed by link-flat.so
+LINK_FLAT_CRTS := $(top_builddir)lib/Scrt1.o $(top_builddir)lib/crti.o \
+	$(top_builddir)lib/crtn.o
+
+# Create a shared flat library from the archive named by the first dependency.
+# $@ names the shared library's .gdb file, not the flat file itself.
+# (This is because the .gdb suffix makes the ELF file more distinctive
+# than the suffixless flat file.)
+#
+# Argument 1 is the shared library file -- i.e. $(@:.gdb=) -- and argument 2
+# is the shared library identifier.  If it wasn't for $(disp_ld), we could
+# avoid passing $(@:.gdb=) as an argument and use $(@:.gdb=) instead of $(1).
+define link-flat.so
+	$(Q)$(INSTALL) -d $(dir $@)
+	$(Q)$(RM) $(1) $@
+	@$(disp_ld)
+	$(Q)$(LD) $(LDFLAGS-$(notdir $@)) -o $(1) \
+		-elf2flt -shared-lib-id $(2) $(top_builddir)lib/Scrt1.o \
+		$(top_builddir)/lib/crti.o --whole-archive $(firstword $^) \
+		--no-whole-archive $(LIBS-$(notdir $@)) $(LIBGCC) \
+		$(top_builddir)/lib/crtn.o
+endef
+
 define linkm.so
 	$(Q)$(INSTALL) -d $(dir $@)
 	$(Q)$(RM) $@ $@.$(2) $(dir $@)$(1)
@@ -181,7 +207,7 @@ $(headers_dep):
 
 CRT := crt1
 
-ifeq ($(HAVE_SHARED),y)
+ifeq ($(HAVE_SHARED)$(HAVE_SHARED_FLAT),y)
 CRTS=$(top_builddir)lib/$(CRT).o $(top_builddir)lib/S$(CRT).o
 else
 CRTS=$(top_builddir)lib/$(CRT).o

Rules.mak

@@ -506,16 +506,3 @@ ifeq ($(UCLIBC_CTOR_DTOR),y)
 SHARED_START_FILES:=$(top_builddir)lib/crti.o $(LIBGCC_DIR)crtbeginS.o
 SHARED_END_FILES:=$(LIBGCC_DIR)crtendS.o $(top_builddir)lib/crtn.o
 endif
-
-########################################
-#
-# uClinux shared lib support
-#
-
-ifeq ($(CONFIG_BINFMT_SHARED_FLAT),y)
-  # For the shared version of this, we specify no stack and its library ID
-  FLTFLAGS += -s 0
-  LIBID=1
-  export LIBID FLTFLAGS
-  SHARED_TARGET = lib/libc
-endif

extra/Configs/Config.in

@@ -196,6 +196,30 @@ config DOPIC
 	  If you wish to build all of uClibc as PIC objects, then answer Y here.
 	  If you are unsure, then you should answer N.
 
+config HAVE_SHARED_FLAT
+	bool "Generate a flat-format shared library"
+	default n
+	depends on !ARCH_USE_MMU
+	help
+	  Answer Y here if you are using uClinux and wish to build uClibc
+	  as a flat-format shared library.
+
+config SHARED_FLAT_ID
+	int "Shared library id"
+	default 1
+	depends on HAVE_SHARED_FLAT
+	help
+	  When using flat shared libraries, every library has a unique
+	  system-wide identifier.  Identifier 0 is reserved for
+	  executables and true shared libraries have identifiers
+	  starting at 1.  The maximum shared library identifier is
+	  determined by the kernel and is usually 3.  Shared library
+	  N must be available on the target system as "/lib/libN.so".
+
+	  When a shared C library is used, it usually has identifier 1,
+	  but you can use this option to select a different identifier
+	  if you need to.
+
 config HAVE_NO_SHARED
 	bool
 	default n

libc/Makefile.in

@@ -50,6 +50,7 @@ libc-multi-y = $(filter-out $(libc-nomulti-y:.o=.c),$(all_sources))
 endif
 
 lib-a-y += $(top_builddir)lib/libc.a
+lib-gdb-y += $(top_builddir)lib/libc.gdb
 lib-so-y += $(libc)
 objclean-y += libc_clean
 
@@ -89,5 +90,8 @@ $(top_builddir)lib/libc.a: $(libc-a-y) | $(crt-y)
 	$(do_strip)
 	$(do_ar)
 
+$(top_builddir)lib/libc.gdb: $(top_builddir)lib/libc.a $(LINK_FLAT_CRTS)
+	$(call link-flat.so,$(@:.gdb=),$(SHARED_FLAT_ID))
+
 libc_clean:
 	$(RM) $(libc_OUT)/*.{o,os,oS,a}

libc/misc/internals/Makefile.in

@@ -18,7 +18,9 @@ MISC_INTERNALS_OBJ := $(patsubst %.c,$(MISC_INTERNALS_OUT)/%.o,$(CSRC))
 libc-y += $(MISC_INTERNALS_OBJ)
 libc-shared-y += $(MISC_INTERNALS_OUT)/__uClibc_main.oS
 libc-static-y += $(MISC_INTERNALS_OUT)/__uClibc_main.o
-
+libc-static-$(HAVE_SHARED_FLAT) += \
+  $(MISC_INTERNALS_OUT)/shared_flat_initfini.o \
+  $(MISC_INTERNALS_OUT)/shared_flat_add_library.o
 libc-nomulti-y += $(MISC_INTERNALS_OUT)/__uClibc_main.o
 
 objclean-y += misc_internals_objclean

libc/misc/internals/__uClibc_main.c

@@ -88,7 +88,9 @@ extern void weak_function _locale_init(void) attribute_hidden;
 extern void weak_function __pthread_initialize_minimal(void);
 #endif
 
-#ifdef __UCLIBC_CTOR_DTOR__
+/* If __HAVE_SHARED_FLAT__, all array initialisation and finalisation
+ * is handled by the routines passed to __uClibc_main().  */
+#if defined (__UCLIBC_CTOR_DTOR__) && !defined (__HAVE_SHARED_FLAT__)
 extern void _dl_app_init_array(void);
 extern void _dl_app_fini_array(void);
 # ifndef SHARED
@@ -247,9 +249,11 @@ libc_hidden_proto(__uClibc_fini)
 void __uClibc_fini(void)
 {
 #ifdef __UCLIBC_CTOR_DTOR__
+    /* If __HAVE_SHARED_FLAT__, all array finalisation is handled
+     * by __app_fini.  */
 # ifdef SHARED
     _dl_app_fini_array();
-# else
+# elif !defined (__HAVE_SHARED_FLAT__)
     size_t i = __fini_array_end - __fini_array_start;
     while (i-- > 0)
 	(*__fini_array_start [i]) ();
@@ -348,7 +352,9 @@ void __uClibc_main(int (*main)(int, char **, char **), int argc,
     /* Arrange for the application's dtors to run before we exit.  */
     __app_fini = app_fini;
 
-# ifndef SHARED
+    /* If __HAVE_SHARED_FLAT__, all array initialisation is handled
+     * by __app_init.  */
+# if !defined (SHARED) && !defined (__HAVE_SHARED_FLAT__)
     /* For dynamically linked executables the preinit array is executed by
        the dynamic linker (before initializing any shared object).
        For static executables, preinit happens rights before init.  */
@@ -363,9 +369,11 @@ void __uClibc_main(int (*main)(int, char **, char **), int argc,
     if (app_init!=NULL) {
 	app_init();
     }
+    /* If __HAVE_SHARED_FLAT__, all array initialisation is handled
+     * by __app_init.  */
 # ifdef SHARED
     _dl_app_init_array();
-# else
+# elif !defined (__HAVE_SHARED_FLAT__)
     {
 	const size_t size = __init_array_end - __init_array_start;
 	size_t i;

libc/misc/internals/shared_flat_add_library.c

@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2006 CodeSourcery Inc
+ *
+ * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
+ *
+ * This file defines __shared_flat_add_library.  If a library has
+ * initialistion and finalisation code, it should use this routine
+ * to register itself.
+ */
+#include "shared_flat_lib.h"
+
+/* The initialisation and finalisation symbols for this library.  */
+extern void _init(void) attribute_hidden weak_function;
+extern void _fini(void) attribute_hidden weak_function;
+extern void (*__preinit_array_start[])(void) attribute_hidden;
+extern void (*__preinit_array_end[])(void) attribute_hidden;
+extern void (*__init_array_start[])(void) attribute_hidden;
+extern void (*__init_array_end[])(void) attribute_hidden;
+extern void (*__fini_array_start[])(void) attribute_hidden;
+extern void (*__fini_array_end[])(void) attribute_hidden;
+
+/* The shared_flat_lib structure that describes this library.  */
+static struct shared_flat_lib this_lib = {
+	0,
+	0,
+	__preinit_array_start,
+	__preinit_array_end,
+	__init_array_start,
+	__init_array_end,
+	__fini_array_start,
+	__fini_array_end,
+	_init,
+	_fini
+};
+
+/* Add this_lib to the end of the global list. */
+void __shared_flat_add_library(void) attribute_hidden;
+void __shared_flat_add_library(void)
+{
+	this_lib.prev = __last_shared_lib;
+	if (this_lib.prev)
+		this_lib.prev->next = &this_lib;
+	else
+		__first_shared_lib = &this_lib;
+	__last_shared_lib = &this_lib;
+}

libc/misc/internals/shared_flat_initfini.c

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2006 CodeSourcery Inc
+ *
+ * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
+ *
+ * This file defines the main initialisation and finalisation code for
+ * shared flat libraries.  It in turn calls the initialisation and
+ * finalisation code for each registered library.
+ */
+#include "shared_flat_lib.h"
+
+/* A doubly-linked list of shared libraries.  Those nearer the head
+ * of the list should be initialised first and finalised last.  */
+struct shared_flat_lib *__first_shared_lib;
+struct shared_flat_lib *__last_shared_lib;
+
+void __shared_flat_init(void)
+{
+	struct shared_flat_lib *lib;
+	void (**start)(void);
+	void (**end)(void);
+
+	for (lib = __first_shared_lib; lib; lib = lib->next) {
+		end = lib->preinit_array_end;
+		for (start = lib->preinit_array_start; start < end; start++)
+			(*start)();
+	}
+
+	for (lib = __first_shared_lib; lib; lib = lib->next) {
+		if (lib->init)
+			lib->init();
+
+		end = lib->init_array_end;
+		for (start = lib->init_array_start; start < end; start++)
+			(*start)();
+	}
+}
+
+void __shared_flat_fini(void)
+{
+	struct shared_flat_lib *lib;
+	void (**start)(void);
+	void (**end)(void);
+
+	for (lib = __last_shared_lib; lib; lib = lib->prev) {
+		start = lib->fini_array_start;
+		for (end = lib->fini_array_end; end > start;)
+			(*--end)();
+
+		if (lib->fini)
+			lib->fini();
+	}
+}

libc/misc/internals/shared_flat_lib.h

@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2006 CodeSourcery Inc
+ *
+ * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
+ *
+ * This file defines the shared_flat_lib structure and the global library
+ * list.   The structure is used to provide something close to ELF-like
+ * initialisation and finalisation when using shared flat libraries.
+ */
+#ifndef __SHARED_FLAT_LIB__
+#define __SHARED_FLAT_LIB__
+
+struct shared_flat_lib {
+	struct shared_flat_lib *prev;
+	struct shared_flat_lib *next;
+	/* .preinit_array is usually only supported for executables.
+	 * However, the distinction between the executable and its
+	 * shared libraries isn't as pronounced for flat files; a shared
+	 * library is really just a part of an executable that can be
+	 * shared with other executables.  We therefore allow
+	 * .preinit_array to be used in libraries too.  */
+	void (**preinit_array_start)(void);
+	void (**preinit_array_end)(void);
+	void (**init_array_start)(void);
+	void (**init_array_end)(void);
+	void (**fini_array_start)(void);
+	void (**fini_array_end)(void);
+	void (*init)(void);
+	void (*fini)(void);
+};
+
+extern struct shared_flat_lib *__first_shared_lib;
+extern struct shared_flat_lib *__last_shared_lib;
+
+#endif

libc/sysdeps/linux/m68k/bsd-setjmp.S

@@ -5,6 +5,7 @@
 #define _ASM
 #define _SETJMP_H
 #include <bits/setjmp.h>
+#include "m68k_pic.S"
 
 .globl setjmp;
 .type  setjmp,@function
@@ -18,6 +19,5 @@ setjmp:
 	fmovemx %fp2-%fp7, %a0@(JB_FPREGS)
 #endif
 	clrl	%d0
-	lea		__sigjmp_save-.-8, %a0
-	jmp		0(%pc, %a0)
+	JUMP	__sigjmp_save,%a0
 

libc/sysdeps/linux/m68k/clone.S

@@ -8,6 +8,7 @@
 #include <features.h>
 #include <bits/errno.h>
 #include <sys/syscall.h>
+#include "m68k_pic.S"
 
 /* int _clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg); */
 
@@ -21,11 +22,11 @@ clone:
 	movel   4(%sp), %d1             /* no NULL function pointers */
 	movel	%d1, %a0
 	tstl    %d1
-	jbeq    __syscall_error
+	beq.w	__syscall_error_trampoline
 	movel   8(%sp), %d1             /* no NULL stack pointers */
 	movel	%d1, %a1
 	tstl    %d1
-	jbeq    __syscall_error
+	beq.w   __syscall_error_trampoline
 
 	/* Allocate space and copy the argument onto the new stack.  */
 	movel   16(%sp), -(%a1)
@@ -50,7 +51,7 @@ clone:
 #endif
 
 	tstl    %d0
-	jbmi    __syscall_error
+	bmi.w   __syscall_error_trampoline
 	beq.w   thread_start
 
 	rts
@@ -62,3 +63,7 @@ thread_start:
 	movel	#__NR_exit, %d0
 	trap	#0
 	/*jsr    exit*/
+
+__syscall_error_trampoline:
+	JUMP	__syscall_error,%a0
+

libc/sysdeps/linux/m68k/crt1.S

@@ -34,6 +34,10 @@
    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
    02111-1307 USA.  */
 
+#include <features.h>
+#include "m68k_pic.S"
+
+#ifndef L_Scrt1
 /* This is the canonical entry point, usually the first thing in the text
    segment.  The SVR4/m68k ABI says that when the entry point runs,
    most registers' values are unspecified, except for:
@@ -60,8 +64,6 @@
 		8(%sp)			envp
 */
 
-#include <features.h>
-
 	.text
 	.type	_init,%function
 	.type	_fini,%function
@@ -76,6 +78,17 @@ _start:
 	   the outermost frame obviously.  */
 	sub.l %fp, %fp
 
+#if !defined __ARCH_USE_MMU__ && defined __PIC__
+	/* Set up the global pointer.  The GOT is at the beginning of the
+	   data segment, whose address is in %d5.  */
+	move.l %d5,%a5
+	.equ have_current_got, 1
+#endif
+	
+#ifdef __HAVE_SHARED_FLAT__
+	CALL __shared_flat_add_library,%a1
+#endif
+
 	/* Extract the arguments as encoded on the stack and set up the
 	   arguments for `main': argc, argv.  envp will be determined
 	   later in __libc_start_main.  */
@@ -100,19 +113,35 @@ _start:
 
 	/* Push the address of our own entry points to `.fini' and
 	   `.init'.  */
-	pea _fini
-	pea _init
+#if defined __HAVE_SHARED_FLAT__
+	PEA_TEXT __shared_flat_fini,%a1
+	PEA_TEXT __shared_flat_init,%a1
+#else
+	PEA_TEXT _fini,%a1
+	PEA_TEXT _init,%a1
+#endif
 
 	pea (%a0)		/* Push second argument: argv.  */
 	move.l %d0, -(%sp)	/* Push first argument: argc.  */
 
-	pea main
+	PEA_TEXT main,%a1
 
 	/* Call the user's main function, and exit with its value.  But
 	   let the libc call main.  */
-	jbsr __uClibc_main
+	CALL __uClibc_main,%a1
 
 	illegal			/* Crash if somehow `exit' does return.  */
+#else
+	.text
+	.globl lib_main
+	.hidden lib_main
+	.type lib_main,@function
+lib_main:
+	move.l %d5,%a5
+	JUMP __shared_flat_add_library,%a0
+
+	.hidden _current_shared_library_a5_offset_
+#endif
 
 /* Define a symbol for the first piece of initialized data.  */
 	.data

libc/sysdeps/linux/m68k/crti.S

@@ -1,27 +1,17 @@
-	.file	"initfini.c"
-#APP
-	
+#include "m68k_pic.S"
+
 	.section .init
-#NO_APP
 	.align	2
 	.globl	_init
 	.type	_init, @function
 _init:
-	link.w %a6,#0
-#APP
-	
-	.align 2
-	
+	link.w	%a6,#0
+	INIT_GP
 	
 	.section .fini
-#NO_APP
 	.align	2
 	.globl	_fini
 	.type	_fini, @function
 _fini:
-	link.w %a6,#0
-#APP
-	.align 2
-	
-	
-	.ident	"GCC: (GNU) 3.3.2"
+	link.w	%a6,#0
+	INIT_GP

libc/sysdeps/linux/m68k/crtn.S

@@ -1,26 +1,11 @@
-	.file	"initfini.c"
-#APP
-	
+#include "m68k_pic.S"
+
 	.section .init
-#NO_APP
-	.align	2
-	.globl	_init
-	.type	_init, @function
-#NO_APP
-	unlk %a6
+	FINI_GP
+	unlk	%a6
 	rts
-	.size	_init, .-_init
-#APP
 	
 	.section .fini
-#NO_APP
-	.align	2
-	.globl	_fini
-	.type	_fini, @function
-#NO_APP
-	unlk %a6
+	FINI_GP
+	unlk	%a6
 	rts
-	.size	_fini, .-_fini
-#APP
-	
-	.ident	"GCC: (GNU) 3.3.2"

libc/sysdeps/linux/m68k/m68k_pic.S

@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2006 CodeSourcery Inc
+ *
+ * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
+ *
+ * This file defines some m68k assembly macros for handling the differences
+ * between PIC and non-PIC.
+ */
+#include <features.h>
+
+	/* When assembling code for shared flat libraries, this is nonzero
+	 * if %a5 points the current library's GOT.  */
+	.equ	have_current_got, 0
+
+	/* Perform the equivalent of "<op> <target>", where <target> is
+	 * a text address.  <tmp> is available as a temporary address
+	 * register.  */
+	.macro	DO_TEXT op,target,tmp
+#if defined __HAVE_SHARED_FLAT__
+	.ifne	have_current_got
+	move.l \target@GOT(%a5),\tmp
+	.else
+	move.l _current_shared_library_a5_offset_(%a5),\tmp
+	move.l \target@GOT(\tmp),\tmp
+	.endif
+	\op (\tmp)
+#elif defined __PIC__
+	lea \target-.-8,\tmp
+	\op (%pc,\tmp)
+#else
+	\op \target
+#endif
+	.endm
+
+	/* Do "pea <target>" when <target> is a text address.
+	 * <tmp> is available as a temporary register.  */
+	.macro PEA_TEXT target,tmp
+	DO_TEXT pea,\target,\tmp
+	.endm
+
+	/* Likewise jsr.  */
+	.macro CALL target,tmp
+	DO_TEXT jsr,\target,\tmp
+	.endm
+
+	/* Likewise jmp.  */
+	.macro JUMP target,tmp
+	DO_TEXT jmp,\target,\tmp
+	.endm
+
+	/* Initialize the global pointer, if functions need to do that.  */
+	.macro INIT_GP
+#if defined __HAVE_SHARED_FLAT__
+	move.l	%a5,-(%sp)
+	move.l _current_shared_library_a5_offset_(%a5),%a5
+#endif
+	.endm
+
+	/* Undo the effects of INIT_GP.  */
+	.macro FINI_GP
+#if defined __HAVE_SHARED_FLAT__
+	move.l	(%sp)+,%a5
+#endif
+	.endm

libc/sysdeps/linux/m68k/setjmp.S

@@ -5,6 +5,7 @@
 #define _ASM
 #define _SETJMP_H
 #include <bits/setjmp.h>
+#include "m68k_pic.S"
 
 .globl __sigsetjmp;
 .type  __sigsetjmp,@function
@@ -18,6 +19,5 @@ __sigsetjmp:
 	fmovemx %fp2-%fp7, %a0@(JB_FPREGS)
 #endif
 	clrl	%d0
-	lea		__sigjmp_save-.-8, %a0
-	jmp		0(%pc, %a0)
+	JUMP	__sigjmp_save,%a0