configure: Replace -Wl,-r,-d with -Wl,-r and add -fno-common

In GNU ld and ld.lld, -d is used with -r to allocate space to COMMON symbols.
This behavior is presumably to work around legacy projects which inspect
relocatable output by themselves and do not handle COMMON symbols. The GRUB
does not do this.

See https://github.com/llvm/llvm-project/issues/53660
-d is quite useless and ld.lld 15.0.0 will make -d no-op.

COMMON symbols have special symbol resolution semantics which can cause surprise
(see https://maskray.me/blog/2022-02-06-all-about-common-symbols). GCC<10 and
Clang<11 defaulted to -fcommon. Just use -fno-common to avoid COMMON symbols.

Signed-off-by: Fangrui Song <maskray@google.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

diff --git a/acinclude.m4 b/acinclude.m4
index 6e14bb553c6d7ce5befcd1a846c23623ff93ccf3..fa7840f09af5f29bd7f023baba56497a049cdc8a 100644 (file)
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -430,7 +430,7 @@ link_nopie_needed=no]
 AC_MSG_CHECKING([whether linker needs disabling of PIE to work])
 AC_LANG_CONFTEST([AC_LANG_SOURCE([[]])])
 
-[if eval "$ac_compile -Wl,-r,-d -nostdlib -Werror -o conftest.o" 2> /dev/null; then]
+[if eval "$ac_compile -Wl,-r -nostdlib -Werror -o conftest.o" 2> /dev/null; then]
   AC_MSG_RESULT([no])
   [# Should we clear up other files as well, having called `AC_LANG_CONFTEST'?
   rm -f conftest.o

diff --git a/conf/Makefile.common b/conf/Makefile.common
index b19b98ee91056aa7a1dde3090c22c4bf1d68b6ef..b343a038ee15be92ae9733bfdf5de580447388a7 100644 (file)
--- a/conf/Makefile.common
+++ b/conf/Makefile.common
@@ -41,7 +41,7 @@ CCASFLAGS_KERNEL = $(CCASFLAGS_CPU) $(CCASFLAGS_PLATFORM)
 STRIPFLAGS_KERNEL = -R .rel.dyn -R .reginfo -R .note -R .comment -R .drectve -R .note.gnu.gold-version -R .MIPS.abiflags -R .ARM.exidx
 
 CFLAGS_MODULE = $(CFLAGS_PLATFORM) -ffreestanding
-LDFLAGS_MODULE = $(LDFLAGS_PLATFORM) -nostdlib $(TARGET_LDFLAGS_OLDMAGIC) -Wl,-r,-d
+LDFLAGS_MODULE = $(LDFLAGS_PLATFORM) -nostdlib $(TARGET_LDFLAGS_OLDMAGIC) -Wl,-r
 CPPFLAGS_MODULE = $(CPPFLAGS_CPU) $(CPPFLAGS_PLATFORM)
 CCASFLAGS_MODULE = $(CCASFLAGS_CPU) $(CCASFLAGS_PLATFORM)
 

diff --git a/configure.ac b/configure.ac
index 5c01af0fab8026ef3b9ebeddb24b601f8f1cc4c8..d1eaafee15f7da27adf741bc81db1943d10e61eb 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -85,9 +85,9 @@ fi
 
 # Enable support for "restrict" keyword and other
 # features from gnu99 C language standard.
-BUILD_CFLAGS="-std=gnu99 $BUILD_CFLAGS"
-HOST_CFLAGS="-std=gnu99 $HOST_CFLAGS"
-TARGET_CFLAGS="-std=gnu99 $TARGET_CFLAGS"
+BUILD_CFLAGS="-std=gnu99 -fno-common $BUILD_CFLAGS"
+HOST_CFLAGS="-std=gnu99 -fno-common $HOST_CFLAGS"
+TARGET_CFLAGS="-std=gnu99 -fno-common $TARGET_CFLAGS"
 
 # Default HOST_CPPFLAGS
 HOST_CPPFLAGS="$HOST_CPPFLAGS -Wall -W"

diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 8022e1c0a794d2034e24a24e403c2250d653c5c9..ac00cc8a2854b8d8fba7786ad7a3e91a11fccf6d 100644 (file)
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -49,26 +49,26 @@ kernel = {
 
   nostrip = emu;
 
-  emu_ldflags              = '-Wl,-r,-d';
-  i386_efi_ldflags         = '-Wl,-r,-d';
+  emu_ldflags              = '-Wl,-r';
+  i386_efi_ldflags         = '-Wl,-r';
   i386_efi_stripflags      = '--strip-unneeded -K start -R .note -R .comment -R .note.gnu.gold-version';
-  x86_64_efi_ldflags       = '-Wl,-r,-d';
+  x86_64_efi_ldflags       = '-Wl,-r';
   x86_64_efi_stripflags    = '--strip-unneeded -K start -R .note -R .comment -R .note.gnu.gold-version';
 
   ia64_efi_cflags = '-fno-builtin -fpic -minline-int-divide-max-throughput';
-  ia64_efi_ldflags = '-Wl,-r,-d';
+  ia64_efi_ldflags = '-Wl,-r';
   ia64_efi_stripflags = '--strip-unneeded -K start -R .note -R .comment -R .note.gnu.gold-version';
 
-  arm_efi_ldflags          = '-Wl,-r,-d';
+  arm_efi_ldflags          = '-Wl,-r';
   arm_efi_stripflags       = '--strip-unneeded -K start -R .note -R .comment -R .note.gnu.gold-version';
 
-  arm64_efi_ldflags          = '-Wl,-r,-d';
+  arm64_efi_ldflags          = '-Wl,-r';
   arm64_efi_stripflags       = '--strip-unneeded -K start -R .note -R .comment -R .note.gnu.gold-version -R .eh_frame';
 
-  riscv32_efi_ldflags      = '-Wl,-r,-d';
+  riscv32_efi_ldflags      = '-Wl,-r';
   riscv32_efi_stripflags   = '--strip-unneeded -K start -R .note -R .comment -R .note.gnu.gold-version -R .eh_frame';
 
-  riscv64_efi_ldflags      = '-Wl,-r,-d';
+  riscv64_efi_ldflags      = '-Wl,-r';
   riscv64_efi_stripflags   = '--strip-unneeded -K start -R .note -R .comment -R .note.gnu.gold-version -R .eh_frame';
 
   i386_pc_ldflags          = '$(TARGET_IMG_LDFLAGS)';
@@ -98,9 +98,9 @@ kernel = {
   i386_qemu_cppflags     = '-DGRUB_BOOT_MACHINE_LINK_ADDR=$(GRUB_BOOT_MACHINE_LINK_ADDR)';
   emu_cflags = '$(CFLAGS_GNULIB)';
   emu_cppflags = '$(CPPFLAGS_GNULIB)';
-  arm_uboot_ldflags       = '-Wl,-r,-d';
+  arm_uboot_ldflags       = '-Wl,-r';
   arm_uboot_stripflags    = '--strip-unneeded -K start -R .note -R .comment -R .note.gnu.gold-version';
-  arm_coreboot_ldflags       = '-Wl,-r,-d';
+  arm_coreboot_ldflags       = '-Wl,-r';
   arm_coreboot_stripflags    = '--strip-unneeded -K start -R .note -R .comment -R .note.gnu.gold-version';
 
   i386_pc_startup = kern/i386/pc/startup.S;

diff --git a/grub-core/genmod.sh.in b/grub-core/genmod.sh.in
index 1250589b3f5f88b52d7ea6de361427339fe7e578..e57c4d9205ca2b33b8b55e8fe96aecaed952a60c 100644 (file)
--- a/grub-core/genmod.sh.in
+++ b/grub-core/genmod.sh.in
@@ -83,9 +83,9 @@ else
     for dep in $deps; do echo "char moddep_$dep[] __attribute__ ((section(\"_moddeps, _moddeps\"))) = \"$dep\";" >>$t2; done
 
     if test -n "$deps"; then
-       @TARGET_CC@ @TARGET_LDFLAGS@ -ffreestanding -nostdlib -o $tmpfile2 $t1 $t2 $tmpfile -Wl,-r,-d
+       @TARGET_CC@ @TARGET_LDFLAGS@ -ffreestanding -nostdlib -o $tmpfile2 $t1 $t2 $tmpfile -Wl,-r
     else
-       @TARGET_CC@ @TARGET_LDFLAGS@ -ffreestanding -nostdlib -o $tmpfile2 $t1 $tmpfile -Wl,-r,-d
+       @TARGET_CC@ @TARGET_LDFLAGS@ -ffreestanding -nostdlib -o $tmpfile2 $t1 $tmpfile -Wl,-r
     fi
     rm -f $t1 $t2 $tmpfile
     mv $tmpfile2 $tmpfile