On 09/03/21 05:52, Bill Wendling wrote:
The -nostdlib flag disables the driver from adding libclang_rt.*.a
during linking. Adding a specific library to the command line then
causes the linker to report unresolved symbols, because the libraries
that resolve those symbols aren't automatically added. Turns out clang
doesn't need to specify that library.
This breaks 32-bit build with clang due to __udivdi3/__umoddi3. Let me
post an alternative.
Paolo
Signed-off-by: Bill Wendling <morbo@xxxxxxxxxx>
---
Makefile | 6 ++++++
arm/Makefile.common | 2 ++
x86/Makefile.common | 2 ++
3 files changed, 10 insertions(+)
diff --git a/Makefile b/Makefile
index e0828fe..61a1276 100644
--- a/Makefile
+++ b/Makefile
@@ -22,10 +22,16 @@ DESTDIR := $(PREFIX)/share/kvm-unit-tests/
cc-option = $(shell if $(CC) -Werror $(1) -S -o /dev/null -xc /dev/null \
> /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
+# cc-name
+# Expands to either gcc or clang
+cc-name = $(shell $(CC) -v 2>&1 | grep -q "clang version" && echo clang || echo gcc)
+
#make sure env CFLAGS variable is not used
CFLAGS =
+ifneq ($(cc-name),clang)
libgcc := $(shell $(CC) --print-libgcc-file-name)
+endif
libcflat := lib/libcflat.a
cflatobjs := \
diff --git a/arm/Makefile.common b/arm/Makefile.common
index a123e85..94922aa 100644
--- a/arm/Makefile.common
+++ b/arm/Makefile.common
@@ -58,7 +58,9 @@ OBJDIRS += lib/arm
libeabi = lib/arm/libeabi.a
eabiobjs = lib/arm/eabi_compat.o
+ifneq ($(cc-name),clang)
libgcc := $(shell $(CC) $(machine) --print-libgcc-file-name)
+endif
FLATLIBS = $(libcflat) $(LIBFDT_archive) $(libgcc) $(libeabi)
%.elf: LDFLAGS = -nostdlib $(arch_LDFLAGS)
diff --git a/x86/Makefile.common b/x86/Makefile.common
index 55f7f28..a96b236 100644
--- a/x86/Makefile.common
+++ b/x86/Makefile.common
@@ -37,7 +37,9 @@ COMMON_CFLAGS += -O1
# stack.o relies on frame pointers.
KEEP_FRAME_POINTER := y
+ifneq ($(cc-name),clang)
libgcc := $(shell $(CC) -m$(bits) --print-libgcc-file-name)
+endif
# We want to keep intermediate file: %.elf and %.o
.PRECIOUS: %.elf %.o
