[PATCH] Build fixes for Cygwin

[PATCH] Build fixes for Cygwin

[Christian Franke]

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This adds Cygwin support to the build system. It adds PE->ELF 
conversion, a linker script and support for HAVE_ASM_USCORE.

Christian

2007-07-20	Christian Franke  <franke@computer.org>

	* Makefile.in: Add autoconf replacements TARGET_IMG_LDSCRIPT,
	TARGET_IMG_LDFLAGS, TARGET_MOD_COPY and EXEEXT.

	* aclocal.m4 (grub_PROG_OBJCOPY_ABSOLUTE): Replace -Wl,-N by
	TARGET_IMG_LDFLAGS_AC.
	(grub_CHECK_STACK_ARG_PROBE): New function.

	* conf/i386-pc.rmk: Replace -Wl,-N by TARGET_IMG_LDFLAGS.

	* conf/i386-pc-cygwin-ld-img.sc: New linker script.

	* configure.ac: Add check for linker script "conf/${target}-img-ld.c"
	to set TARGET_IMG_LD* accordingly.
	Add check for Cygwin to set TARGET_MOD_OBJCOPY accordingly.
	Add call to grub_CHECK_STACK_ARG_PROBE.
	Use TARGET_IMG_LDFLAGS to check start, bss_start, end symbols.

	* genkernsyms.sh.in: Handle HAVE_ASM_USCORE case.

	* genmk.rb: Add TARGET_MOD_OBJCOPY step to convert native linker
	output format to ELF.  Handle HAVE_ASM_USCORE case in strip command.
	Add EXEEXT to CLEANFILES.

	* gensymlist.sh.in: Handle HAVE_ASM_USCORE case.



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diff --git a/Makefile.in b/Makefile.in
index 6f9474c..add81d5 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -68,7 +68,11 @@ TARGET_CFLAGS = @TARGET_CFLAGS@
 TARGET_CPPFLAGS = @TARGET_CPPFLAGS@ -I. -Iinclude -I$(srcdir)/include \
 	-Wall -W
 TARGET_LDFLAGS = @TARGET_LDFLAGS@
+TARGET_IMG_LDSCRIPT = @TARGET_IMG_LDSCRIPT@
+TARGET_IMG_LDFLAGS = @TARGET_IMG_LDFLAGS@
+TARGET_MOD_COPY = @TARGET_MOD_COPY@
 MODULE_LDFLAGS = @MODULE_LDFLAGS@
+EXEEXT = @EXEEXT@
 OBJCOPY = @OBJCOPY@
 STRIP = @STRIP@
 NM = @NM@
diff --git a/aclocal.m4 b/aclocal.m4
index b7cc0a2..ee6c4db 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -73,7 +73,7 @@ else
 fi
 grub_cv_prog_objcopy_absolute=yes
 for link_addr in 2000 8000 7C00; do
-  if AC_TRY_COMMAND([${CC-cc} ${CFLAGS} ${LDFLAGS} -nostdlib -Wl,-N -Wl,-Ttext -Wl,$link_addr conftest.o -o conftest.exec]); then :
+  if AC_TRY_COMMAND([${CC-cc} ${CFLAGS} -nostdlib ${TARGET_IMG_LDFLAGS_AC} -Wl,-Ttext -Wl,$link_addr conftest.o -o conftest.exec]); then :
   else
     AC_MSG_ERROR([${CC-cc} cannot link at address $link_addr])
   fi
@@ -398,3 +398,19 @@ else
   AC_MSG_RESULT([no])
 [fi]
 ])
+
+dnl Check if the C compiler supports `-mstack-arg-probe' (Cygwin).
+AC_DEFUN(grub_CHECK_STACK_ARG_PROBE,[
+[# Smashing stack arg probe.
+sap_possible=yes]
+AC_MSG_CHECKING([whether `$CC' accepts `-mstack-arg-probe'])
+AC_LANG_CONFTEST([[void foo (void) { volatile char a[8]; a[3]; }]])
+[if eval "$ac_compile -S -mstack-arg-probe -o conftest.s" 2> /dev/null; then]
+  AC_MSG_RESULT([yes])
+  [# Should we clear up other files as well, having called `AC_LANG_CONFTEST'?
+  rm -f conftest.s
+else
+  sap_possible=no]
+  AC_MSG_RESULT([no])
+[fi]
+])
diff --git a/conf/i386-pc-cygwin-img-ld.sc b/conf/i386-pc-cygwin-img-ld.sc
new file mode 100644
index 0000000..a41cac7
--- /dev/null
+++ b/conf/i386-pc-cygwin-img-ld.sc
@@ -0,0 +1,53 @@
+/* Linker script to create grub .img files on Cygwin.  */
+
+SECTIONS
+{
+  .text :
+  {
+    start = . ;
+    *(.text)
+    etext = . ;
+  }
+  .data :
+  {
+    __data_start__ = . ;
+    *(.data)
+    __data_end__ = . ;
+  }
+  .rdata :
+  {
+    __rdata_start__ = . ;
+    *(.rdata)
+    __rdata_end__ = . ;
+  }
+  .pdata :
+  {
+    *(.pdata)
+    edata = . ;
+  }
+  .bss :
+  {
+    __bss_start__ = . ;
+    *(.bss)
+    __common_start__ = . ;
+    *(COMMON)
+    __bss_end__ = . ;
+  }
+  .edata :
+  {
+    *(.edata)
+    end = . ;
+  }
+  .stab :
+  {
+    *(.stab)
+  }
+  .stabstr :
+  {
+    *(.stabstr)
+  }
+}
+
+ASSERT("__rdata_end__"=="edata", ".pdata not empty")
+ASSERT("__bss_end__"  =="end"  , ".edata not empty")
+
diff --git a/conf/i386-pc.rmk b/conf/i386-pc.rmk
index b677a96..84c0b7d 100644
--- a/conf/i386-pc.rmk
+++ b/conf/i386-pc.rmk
@@ -16,27 +16,27 @@ pkglib_IMAGES = boot.img diskboot.img kernel.img pxeboot.img lnxboot.img \
 # For boot.img.
 boot_img_SOURCES = boot/i386/pc/boot.S
 boot_img_ASFLAGS = $(COMMON_ASFLAGS)
-boot_img_LDFLAGS = $(COMMON_LDFLAGS) -Wl,-N,-Ttext,7C00
+boot_img_LDFLAGS = $(COMMON_LDFLAGS) $(TARGET_IMG_LDFLAGS) -Wl,-Ttext,7C00
 
 # For pxeboot.img
 pxeboot_img_SOURCES = boot/i386/pc/pxeboot.S
 pxeboot_img_ASFLAGS = $(COMMON_ASFLAGS)
-pxeboot_img_LDFLAGS = $(COMMON_LDFLAGS) -Wl,-N,-Ttext,7C00
+pxeboot_img_LDFLAGS = $(COMMON_LDFLAGS) $(TARGET_IMG_LDFLAGS) -Wl,-Ttext,7C00
 
 # For diskboot.img.
 diskboot_img_SOURCES = boot/i386/pc/diskboot.S
 diskboot_img_ASFLAGS = $(COMMON_ASFLAGS)
-diskboot_img_LDFLAGS = $(COMMON_LDFLAGS) -Wl,-N,-Ttext,8000
+diskboot_img_LDFLAGS = $(COMMON_LDFLAGS) $(TARGET_IMG_LDFLAGS) -Wl,-Ttext,8000
 
 # For lnxboot.img.
 lnxboot_img_SOURCES = boot/i386/pc/lnxboot.S
 lnxboot_img_ASFLAGS = $(COMMON_ASFLAGS)
-lnxboot_img_LDFLAGS = $(COMMON_LDFLAGS) -Wl,-N,-Ttext,6000
+lnxboot_img_LDFLAGS = $(COMMON_LDFLAGS) $(TARGET_IMG_LDFLAGS) -Wl,-Ttext,6000
 
 # For cdboot.img.
 cdboot_img_SOURCES = boot/i386/pc/cdboot.S
 cdboot_img_ASFLAGS = $(COMMON_ASFLAGS)
-cdboot_img_LDFLAGS = $(COMMON_LDFLAGS) -Wl,-N,-Ttext,7C00
+cdboot_img_LDFLAGS = $(COMMON_LDFLAGS) $(TARGET_IMG_LDFLAGS) -Wl,-Ttext,7C00
 
 # For kernel.img.
 kernel_img_SOURCES = kern/i386/pc/startup.S kern/main.c kern/device.c \
@@ -53,7 +53,7 @@ kernel_img_HEADERS = arg.h boot.h cache.h device.h disk.h dl.h elf.h elfload.h \
 	machine/memory.h machine/loader.h machine/vga.h machine/vbe.h machine/kernel.h
 kernel_img_CFLAGS = $(COMMON_CFLAGS)
 kernel_img_ASFLAGS = $(COMMON_ASFLAGS)
-kernel_img_LDFLAGS = $(COMMON_LDFLAGS) -Wl,-N,-Ttext,$(GRUB_MEMORY_MACHINE_LINK_ADDR) $(COMMON_CFLAGS)
+kernel_img_LDFLAGS = $(COMMON_LDFLAGS) $(TARGET_IMG_LDFLAGS) -Wl,-Ttext,$(GRUB_MEMORY_MACHINE_LINK_ADDR) $(COMMON_CFLAGS)
 
 MOSTLYCLEANFILES += symlist.c kernel_syms.lst
 DEFSYMFILES += kernel_syms.lst
diff --git a/configure.ac b/configure.ac
index 1d8bd08..0062901 100644
--- a/configure.ac
+++ b/configure.ac
@@ -188,6 +188,32 @@ AC_CHECK_FUNCS(posix_memalign memalign)
 # Check for target programs.
 #
 
+
+# Use linker script if present, otherwise use builtin -N script.
+AC_MSG_CHECKING([for option to link raw image])
+if test -f "${srcdir}/conf/${target_cpu}-${platform}-${target_os}-img-ld.sc"; then
+  TARGET_IMG_LDSCRIPT='$(top_srcdir)'"/conf/${target_cpu}-${platform}-${target_os}-img-ld.sc"
+  TARGET_IMG_LDFLAGS="-Wl,-T${TARGET_IMG_LDSCRIPT}"
+  TARGET_IMG_LDFLAGS_AC="-Wl,-T${srcdir}/conf/${target_cpu}-${platform}-${target_os}-img-ld.sc"
+else
+  TARGET_IMG_LDSCRIPT=
+  TARGET_IMG_LDFLAGS='-Wl,-N'
+  TARGET_IMG_LDFLAGS_AC='-Wl,-N'
+fi
+AC_SUBST(TARGET_IMG_LDSCRIPT)
+AC_SUBST(TARGET_IMG_LDFLAGS)
+AC_MSG_RESULT([$TARGET_IMG_LDFLAGS_AC])
+
+# For platforms where ELF is not the default link format.
+AC_MSG_CHECKING([for command to convert module to ELF format])
+if test "$host_os" = cygwin; then
+  TARGET_MOD_COPY='$(OBJCOPY) -O elf32-i386'
+else
+  TARGET_MOD_COPY='cp -f'
+fi
+AC_SUBST(TARGET_MOD_COPY)
+AC_MSG_RESULT([$TARGET_MOD_COPY])
+
 # For cross-compiling.
 if test "x$target" != "x$host"; then
   # XXX this depends on the implementation of autoconf!
@@ -278,6 +304,12 @@ grub_CHECK_STACK_PROTECTOR
 if test "x$ssp_possible" = xyes; then
   TARGET_CFLAGS="$TARGET_CFLAGS -fno-stack-protector"
 fi
+grub_CHECK_STACK_ARG_PROBE
+# Cygwin's GCC uses alloca() to probe the stackframe on static
+# stack allocations above some threshold.
+if test x"$sap_possible" = xyes; then
+  TARGET_CFLAGS="$TARGET_CFLAGS -mno-stack-arg-probe"
+fi
 
 AC_SUBST(TARGET_CFLAGS)
 AC_SUBST(TARGET_CPPFLAGS)
@@ -296,9 +328,14 @@ grub_PROG_OBJCOPY_ABSOLUTE
 grub_PROG_LD_BUILD_ID_NONE
 grub_ASM_USCORE
 if test "x$target_cpu" = xi386; then
+  if test ! -z "$TARGET_IMG_LDSCRIPT"; then
+    # Check symbols provided by linker script.
+    CFLAGS="$TARGET_CFLAGS -nostdlib $TARGET_IMG_LDFLAGS_AC -Wl,-Ttext,8000,--defsym,___main=0x8100"
+  fi
   grub_CHECK_START_SYMBOL
   grub_CHECK_BSS_START_SYMBOL
   grub_CHECK_END_SYMBOL
+  CFLAGS="$TARGET_CFLAGS"
   grub_I386_ASM_PREFIX_REQUIREMENT
   grub_I386_ASM_ADDR32
   grub_I386_ASM_ABSOLUTE_WITHOUT_ASTERISK
diff --git a/genkernsyms.sh.in b/genkernsyms.sh.in
index a5e1271..0df0bbf 100644
--- a/genkernsyms.sh.in
+++ b/genkernsyms.sh.in
@@ -16,9 +16,12 @@
 : ${srcdir=@srcdir@}
 : ${CC=@CC@}
 
+u=
+grep "^#define HAVE_ASM_USCORE" config.h >/dev/null 2>&1 && u="_"
+
 $CC -DGRUB_SYMBOL_GENERATOR=1 -E -I. -Iinclude -I"$srcdir/include" $* \
   | grep -v '^#' \
   | sed -n \
-        -e '/EXPORT_FUNC *([a-zA-Z0-9_]*)/{s/.*EXPORT_FUNC *(\([a-zA-Z0-9_]*\)).*/\1 kernel/;p;}' \
-        -e '/EXPORT_VAR *([a-zA-Z0-9_]*)/{s/.*EXPORT_VAR *(\([a-zA-Z0-9_]*\)).*/\1 kernel/;p;}' \
+        -e '/EXPORT_FUNC *([a-zA-Z0-9_]*)/{s/.*EXPORT_FUNC *(\([a-zA-Z0-9_]*\)).*/'"$u"'\1 kernel/;p;}' \
+        -e '/EXPORT_VAR *([a-zA-Z0-9_]*)/{s/.*EXPORT_VAR *(\([a-zA-Z0-9_]*\)).*/'"$u"'\1 kernel/;p;}' \
   | sort -u
diff --git a/genmk.rb b/genmk.rb
index 56dee5c..ba9b127 100644
--- a/genmk.rb
+++ b/genmk.rb
@@ -114,8 +114,10 @@ UNDSYMFILES += #{undsym}
 
 #{@name}: #{pre_obj} #{mod_obj}
 	-rm -f $@
-	$(TARGET_CC) $(#{prefix}_LDFLAGS) $(TARGET_LDFLAGS) $(MODULE_LDFLAGS) -Wl,-r,-d -o $@ $^
-	$(STRIP) --strip-unneeded -K grub_mod_init -K grub_mod_fini -R .note -R .comment $@
+	$(TARGET_CC) $(#{prefix}_LDFLAGS) $(TARGET_LDFLAGS) $(MODULE_LDFLAGS) -Wl,-r,-d -o $@.tmp $^
+	$(TARGET_MOD_COPY) $@.tmp $@ || (rm -f $@.tmp; exit 1)
+	rm -f $@.tmp
+	$(STRIP) --strip-unneeded -K grub_mod_init -K grub_mod_fini -K _grub_mod_init -K _grub_mod_fini -R .note -R .comment $@
 
 #{pre_obj}: $(#{prefix}_DEPENDENCIES) #{objs_str}
 	-rm -f $@
@@ -194,7 +196,7 @@ class Utility
     deps = objs.collect {|obj| obj.suffix('d')}
     deps_str = deps.join(' ');
 
-    "CLEANFILES += #{@name} #{objs_str}
+    "CLEANFILES += #{@name}$(EXEEXT) #{objs_str}
 MOSTLYCLEANFILES += #{deps_str}
 
 #{@name}: $(#{prefix}_DEPENDENCIES) #{objs_str}
diff --git a/gensymlist.sh.in b/gensymlist.sh.in
index d8b9871..d9aa65c 100644
--- a/gensymlist.sh.in
+++ b/gensymlist.sh.in
@@ -16,6 +16,8 @@
 : ${srcdir=@srcdir@}
 : ${CC=@CC@}
 
+u=
+grep "^#define HAVE_ASM_USCORE" config.h >/dev/null 2>&1 && u="_"
 
 cat <<EOF
 /* This file is automatically generated by gensymlist.sh. DO NOT EDIT! */
@@ -62,8 +64,8 @@ EOF
 $CC -DGRUB_SYMBOL_GENERATOR=1 -E -I. -Iinclude -I"$srcdir/include" $* \
   | grep -v '^#' \
   | sed -n \
-        -e '/EXPORT_FUNC *([a-zA-Z0-9_]*)/{s/.*EXPORT_FUNC *(\([a-zA-Z0-9_]*\)).*/      {"\1", \1},/;p;}' \
-        -e '/EXPORT_VAR *([a-zA-Z0-9_]*)/{s/.*EXPORT_VAR *(\([a-zA-Z0-9_]*\)).*/      {"\1", \&\1},/;p;}' \
+        -e '/EXPORT_FUNC *([a-zA-Z0-9_]*)/{s/.*EXPORT_FUNC *(\([a-zA-Z0-9_]*\)).*/      {"'"$u"'\1", \1},/;p;}' \
+        -e '/EXPORT_VAR *([a-zA-Z0-9_]*)/{s/.*EXPORT_VAR *(\([a-zA-Z0-9_]*\)).*/      {"'"$u"'\1", \&\1},/;p;}' \
   | sort -u
 
 cat <<EOF