[Qemu-devel] [PATCH] rules.mak: Also try -r to build modules

[Paolo Bonzini <pbonzini@redhat.com>]

Building qemu fails in distributions where gcc enables PIE by default
(e.g. Debian unstable) with:

/usr/bin/ld: -r and -pie may not be used together

You have to use -r instead of -Wl,-r to avoid gcc passing -pie to the linker
when PIE is enabled and a relocatable object is passed.  However, clang
does not know about -r, so try -Wl,-r first.

Reported-by: Adrian Bunk <bunk@stusta.de>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 configure | 10 ++++++++--
 rules.mak |  2 +-
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/configure b/configure
index 5e66828..c2508fe 100755
--- a/configure
+++ b/configure
@@ -4723,8 +4723,14 @@ EOF
 if ! compile_object ""; then
   error_exit "Failed to compile object file for LD_REL_FLAGS test"
 fi
-if do_cc -nostdlib -Wl,-r -Wl,--no-relax -o $TMPMO $TMPO; then
-  LD_REL_FLAGS="-Wl,--no-relax"
+for i in '-Wl,-r -Wl,--no-relax' -Wl,-r -r; do
+  if do_cc -nostdlib $i -o $TMPMO $TMPO; then
+    LD_REL_FLAGS=$i
+    break
+  fi
+done
+if test "$modules" = "yes" && test "$LD_REL_FLAGS" = ""; then
+  feature_not_found "modules" "Cannot find how to build relocatable objects"
 fi
 
 ##########################################
diff --git a/rules.mak b/rules.mak
index 0333ae3..f4839d2 100644
--- a/rules.mak
+++ b/rules.mak
@@ -93,7 +93,7 @@ module-common.o: CFLAGS += $(DSO_OBJ_CFLAGS)
 	$(if $(findstring /,$@),$(call quiet-command,cp $@ $(subst /,-,$@),"CP","$(subst /,-,$@)"))
 
 
-LD_REL := $(CC) -nostdlib -Wl,-r $(LD_REL_FLAGS)
+LD_REL := $(CC) -nostdlib $(LD_REL_FLAGS)
 
 %.mo:
 	$(call quiet-command,$(LD_REL) -o $@ $^,"LD","$(TARGET_DIR)$@")
-- 
2.9.3