Allow compiling with clang (not really supported though).

	* conf/Makefile.common (CFLAGS_PLATFORM): Don't add -mrtd -mregparm=3
	unconditionally.
	* configure.ac: Add -no-integrated-as when using clangfor asm files.
	Add -mrtd -mregparm=3 on i386 when not using clang.
	* grub-core/kern/misc.c (grub_memset): Add volatile when on clang.

diff --git a/ChangeLog b/ChangeLog
index 3edb0d0..b3e8436 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2013-11-07  Vladimir Serbinenko  <phcoder@gmail.com>
+
+       Allow compiling with clang (not really supported though).
+
+       * conf/Makefile.common (CFLAGS_PLATFORM): Don't add -mrtd -mregparm=3
+       unconditionally.
+       * configure.ac: Add -no-integrated-as when using clangfor asm files.
+       Add -mrtd -mregparm=3 on i386 when not using clang.
+       * grub-core/kern/misc.c (grub_memset): Add volatile when on clang.
+
 2013-11-07  Vladimir Serbinenko  <phcoder@gmail.com>
 
        * grub-core/kern/ieee1275/cmain.c: Add explicit attribute on asm

diff --git a/conf/Makefile.common b/conf/Makefile.common
index 0aec25f..f1d9a55 100644 (file)
--- a/conf/Makefile.common
+++ b/conf/Makefile.common
@@ -6,18 +6,6 @@ export LC_COLLATE := C
 unexport LC_ALL
 
 # Platform specific options
-if COND_i386_pc
-  CFLAGS_PLATFORM += -mrtd -mregparm=3
-endif
-if COND_i386_qemu
-  CFLAGS_PLATFORM += -mrtd -mregparm=3
-endif
-if COND_i386_coreboot
-  CFLAGS_PLATFORM += -mrtd -mregparm=3
-endif
-if COND_i386_ieee1275
-  CFLAGS_PLATFORM += -mrtd -mregparm=3
-endif
 if COND_mips_loongson
   CFLAGS_PLATFORM += -mexplicit-relocs
   CPPFLAGS_PLATFORM = -DUSE_ASCII_FALLBACK

diff --git a/configure.ac b/configure.ac
index 020c769..37d9289 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -480,6 +480,45 @@ if test "x$target_cpu" != xi386 && test "x$target_cpu" != xx86_64; then
 TARGET_CFLAGS="$TARGET_CFLAGS -Wcast-align"
 fi
 
+AC_CACHE_CHECK([if compiling with clang], [grub_cv_cc_target_clang]
+[AC_COMPILE_IFELSE(
+[AC_LANG_PROGRAM([], [[
+#ifdef __clang__
+#error "is clang"
+#endif
+]])],
+[grub_cv_cc_target_clang=no], [grub_cv_cc_target_clang=yes])])
+
+if test "x$grub_cv_cc_target_clang" = xyes; then
+   TARGET_CCASFLAGS="$TARGET_CCASFLAGS -no-integrated-as"
+fi
+
+if test "x$target_cpu" = xi386 && test "x$platform" != xemu; then
+  TARGET_CFLAGS="$TARGET_CFLAGS -march=i386"
+fi
+
+if test "x$target_m32" = x1; then
+  # Force 32-bit mode.
+  TARGET_CFLAGS="$TARGET_CFLAGS -m32"
+  TARGET_CCASFLAGS="$TARGET_CCASFLAGS -m32"
+  TARGET_CPPFLAGS="$TARGET_CPPFLAGS -m32"
+  TARGET_LDFLAGS="$TARGET_LDFLAGS -m32"
+  TARGET_MODULE_FORMAT="elf32"
+fi
+
+if test "x$target_m64" = x1; then
+  # Force 64-bit mode.
+  TARGET_CFLAGS="$TARGET_CFLAGS -m64"
+  TARGET_CCASFLAGS="$TARGET_CCASFLAGS -m64"
+  TARGET_CPPFLAGS="$TARGET_CPPFLAGS -m64"
+  TARGET_LDFLAGS="$TARGET_LDFLAGS -m64"
+  TARGET_MODULE_FORMAT="elf64"
+fi
+
+if test "x$grub_cv_cc_target_clang" = xno && test "x$target_cpu" = xi386 && test "x$platform" != xemu && test "x$platform" != xefi; then
+   TARGET_CFLAGS="$TARGET_CFLAGS -mrtd -mregparm=3"
+fi
+
 # Force no alignment to save space on i386.
 if test "x$target_cpu" = xi386; then
   AC_CACHE_CHECK([whether -falign-loops works], [grub_cv_cc_falign_loop], [
@@ -647,28 +686,6 @@ enable_efiemu=no
 fi
 AC_SUBST([enable_efiemu])
 
-if test "x$target_cpu" = xi386 && test "x$platform" != xemu; then
-  TARGET_CFLAGS="$TARGET_CFLAGS -march=i386"
-fi
-
-if test "x$target_m32" = x1; then
-  # Force 32-bit mode.
-  TARGET_CFLAGS="$TARGET_CFLAGS -m32"
-  TARGET_CCASFLAGS="$TARGET_CCASFLAGS -m32"
-  TARGET_CPPFLAGS="$TARGET_CPPFLAGS -m32"
-  TARGET_LDFLAGS="$TARGET_LDFLAGS -m32"
-  TARGET_MODULE_FORMAT="elf32"
-fi
-
-if test "x$target_m64" = x1; then
-  # Force 64-bit mode.
-  TARGET_CFLAGS="$TARGET_CFLAGS -m64"
-  TARGET_CCASFLAGS="$TARGET_CCASFLAGS -m64"
-  TARGET_CPPFLAGS="$TARGET_CPPFLAGS -m64"
-  TARGET_LDFLAGS="$TARGET_LDFLAGS -m64"
-  TARGET_MODULE_FORMAT="elf64"
-fi
-
 case "$target_os" in
   cygwin)
     ;;

diff --git a/grub-core/kern/misc.c b/grub-core/kern/misc.c
index e940acb..c875d85 100644 (file)
--- a/grub-core/kern/misc.c
+++ b/grub-core/kern/misc.c
@@ -454,6 +454,15 @@ grub_strndup (const char *s, grub_size_t n)
   return p;
 }
 
+/* clang detects that we're implementing here a memset so it decides to
+   optimise and calls memset resulting in infinite recursion. With volatile
+   we make it not optimise in this way.  */
+#ifdef __clang__
+#define VOLATILE_CLANG volatile
+#else
+#define VOLATILE_CLANG
+#endif
+
 void *
 grub_memset (void *s, int c, grub_size_t len)
 {
@@ -470,13 +479,13 @@ grub_memset (void *s, int c, grub_size_t len)
 
       while (len > 0 && (((grub_addr_t) p) & (sizeof (unsigned long) - 1)))
        {
-         *(grub_uint8_t *) p = pattern8;
+         *(VOLATILE_CLANG grub_uint8_t *) p = pattern8;
          p = (grub_uint8_t *) p + 1;
          len--;
        }
       while (len >= sizeof (unsigned long))
        {
-         *(unsigned long *) p = patternl;
+         *(VOLATILE_CLANG unsigned long *) p = patternl;
          p = (unsigned long *) p + 1;
          len -= sizeof (unsigned long);
        }
@@ -484,7 +493,7 @@ grub_memset (void *s, int c, grub_size_t len)
 
   while (len > 0)
     {
-      *(grub_uint8_t *) p = pattern8;
+      *(VOLATILE_CLANG grub_uint8_t *) p = pattern8;
       p = (grub_uint8_t *) p + 1;
       len--;
     }