[xen master] xen: Fix Clang -Wunicode diagnostic when building asm-macros

[patchbot@xxxxxxx]

commit 53f0d02040b1df08f0589f162790ca376e1c2040
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Thu Feb 23 21:53:26 2023 +0000
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Fri Feb 24 17:44:29 2023 +0000

    xen: Fix Clang -Wunicode diagnostic when building asm-macros
    
    While trying to work around a different Clang-IAS bug (parent changeset), I
    stumbled onto:
    
      In file included from arch/x86/asm-macros.c:3:
      ./arch/x86/include/asm/spec_ctrl_asm.h:144:19: error: \u used with
      no following hex digits; treating as '\' followed by identifier 
[-Werror,-Wunicode]
      .L\@_fill_rsb_loop\uniq:
                        ^
    
    It turns out that Clang -E is sensitive to the file extension of the source
    file it is processing.  Furthermore, C explicitly permits the use of \u
    escapes in identifier names, so the diagnostic would be reasonable in
    principle if we trying to compile the result.
    
    asm-macros should really have been .S from the outset, as it is ultimately
    generating assembly, not C.  Rename it, which causes Clang not to complain.
    
    We need to introduce rules for generating a .i file from .S, and 
substituting
    c_flags for a_flags lets us drop the now-redundant -D__ASSEMBLY__.
    
    No functional change.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/Rules.mk              | 6 ++++++
 xen/arch/x86/Makefile     | 2 +-
 xen/arch/x86/asm-macros.S | 3 +++
 xen/arch/x86/asm-macros.c | 3 ---
 4 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/xen/Rules.mk b/xen/Rules.mk
index d6b7cec0a8..59072ae8df 100644
--- a/xen/Rules.mk
+++ b/xen/Rules.mk
@@ -273,6 +273,9 @@ $(filter %.init.o,$(obj-y) $(obj-bin-y) $(extra-y)): 
$(obj)/%.init.o: $(obj)/%.o
 quiet_cmd_cpp_i_c = CPP     $@
 cmd_cpp_i_c = $(CPP) $(call cpp_flags,$(c_flags)) -MQ $@ -o $@ $<
 
+quiet_cmd_cpp_i_S = CPP     $@
+cmd_cpp_i_S = $(CPP) $(call cpp_flags,$(a_flags)) -MQ $@ -o $@ $<
+
 quiet_cmd_cc_s_c = CC      $@
 cmd_cc_s_c = $(CC) $(filter-out -Wa$(comma)%,$(c_flags)) -S $< -o $@
 
@@ -282,6 +285,9 @@ cmd_cpp_s_S = $(CPP) $(call cpp_flags,$(a_flags)) -MQ $@ -o 
$@ $<
 $(obj)/%.i: $(src)/%.c FORCE
        $(call if_changed_dep,cpp_i_c)
 
+$(obj)/%.i: $(src)/%.S FORCE
+       $(call if_changed_dep,cpp_i_S)
+
 $(obj)/%.s: $(src)/%.c FORCE
        $(call if_changed_dep,cc_s_c)
 
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 177a2ff742..5accbe4c67 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -240,7 +240,7 @@ $(obj)/efi/buildid.o $(obj)/efi/relocs-dummy.o: ;
 .PHONY: include
 include: $(objtree)/arch/x86/include/asm/asm-macros.h
 
-$(obj)/asm-macros.i: CFLAGS-y += -D__ASSEMBLY__ -P
+$(obj)/asm-macros.i: CFLAGS-y += -P
 
 $(objtree)/arch/x86/include/asm/asm-macros.h: $(obj)/asm-macros.i 
$(src)/Makefile
        $(call filechk,asm-macros.h)
diff --git a/xen/arch/x86/asm-macros.S b/xen/arch/x86/asm-macros.S
new file mode 100644
index 0000000000..891d86c765
--- /dev/null
+++ b/xen/arch/x86/asm-macros.S
@@ -0,0 +1,3 @@
+#include <asm/asm-defns.h>
+#include <asm/alternative-asm.h>
+#include <asm/spec_ctrl_asm.h>
diff --git a/xen/arch/x86/asm-macros.c b/xen/arch/x86/asm-macros.c
deleted file mode 100644
index 891d86c765..0000000000
--- a/xen/arch/x86/asm-macros.c
+++ /dev/null
@@ -1,3 +0,0 @@
-#include <asm/asm-defns.h>
-#include <asm/alternative-asm.h>
-#include <asm/spec_ctrl_asm.h>
--
generated by git-patchbot for /home/xen/git/xen.git#master