[PATCH] Check linker for --image-base support

In several scenarios, configure tests assume it's safe to use
'-Wl,-Ttext,<address>', but starting with ld.lld-21, blindly using that
flag may result in configure-test failures due to ld.lld failing to
link. The failure is because ld.lld-21 no longer allows the specified
address is less than the base address.

However, ld.lld-21+ and ld.bfd-2.44+ both provide support for the
--image-base flag making it preferable over the older `-Ttext` flag.

Fixes: 67662
Signed-off-by: Nicholas Vinson <[email protected]>
---
 acinclude.m4 |  5 +++++
 configure.ac | 14 ++++++++++++--
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/acinclude.m4 b/acinclude.m4
index fa7840f09..70c1912f8 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -79,6 +79,11 @@ AC_DEFUN([grub_PROG_OBJCOPY_ABSOLUTE],
 [AC_MSG_CHECKING([whether ${TARGET_OBJCOPY} works for absolute addresses])
 AC_CACHE_VAL(grub_cv_prog_objcopy_absolute,
 [cat > conftest.c <<\EOF
+asm (
+    ".globl start, _start, __start\n"
+    ".ifdef cmain; .set start = _start = __start = cmain\n.endif\n"
+    ".ifdef _cmain; .set start = _start = __start = _cmain\n.endif\n"
+);
 void cmain (void);
 void
 cmain (void)
diff --git a/configure.ac b/configure.ac
index 17937baf4..c9e2c5b8c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1461,7 +1461,6 @@ elif test x$grub_cv_target_cc_link_format = x-mi386pe || test x$grub_cv_target_c
   TARGET_IMG_LDSCRIPT='$(top_srcdir)'"/conf/i386-cygwin-img-ld.sc"
   TARGET_IMG_LDFLAGS="-Wl,-T${TARGET_IMG_LDSCRIPT}"
   TARGET_IMG_LDFLAGS_AC="-Wl,-T${srcdir}/conf/i386-cygwin-img-ld.sc"
-  TARGET_IMG_BASE_LDOPT="-Wl,-Ttext"
   TARGET_IMG_CFLAGS=
 else
   TARGET_APPLE_LINKER=0
@@ -1469,7 +1468,6 @@ else
   TARGET_IMG_LDSCRIPT=
   TARGET_IMG_LDFLAGS='-Wl,-N'
   TARGET_IMG_LDFLAGS_AC='-Wl,-N'
-  TARGET_IMG_BASE_LDOPT="-Wl,-Ttext"
   TARGET_IMG_CFLAGS=
 fi
 
@@ -1795,6 +1793,18 @@ LIBS=""
 grub_ASM_USCORE
 grub_PROG_TARGET_CC
 if test "x$TARGET_APPLE_LINKER" != x1 ; then
+AX_CHECK_LINK_FLAG([-Wl,--image-base,0x400000],
+    [TARGET_IMG_BASE_LDOPT="-Wl,--image-base"],
+    [TARGET_IMG_BASE_LDOPT="-Wl,-Ttext"],
+    [],
+    [[
+asm (".globl start; start:");
+asm (".globl _start; _start:");
+asm (".globl __start; __start:");
+void __main (void);
+void __main (void) {}
+int main (void);
+]])
 grub_PROG_OBJCOPY_ABSOLUTE
 fi
 grub_PROG_LD_BUILD_ID_NONE
-- 
2.51.2


_______________________________________________
Grub-devel mailing list
[email protected]
https://lists.gnu.org/mailman/listinfo/grub-devel