[XEN PATCH v4 18/18] build,include: rework compat-build-header.py

[Anthony PERARD <anthony.perard@citrix.com>]

Replace a mix of shell script and python script by all python script.

Remove the unnecessary "grep -v '^# [0-9]'". It is to hide the
linemarkers generated by the preprocessor. But adding -P inhibit there
generation, thus the grep isn't needed anymore.

gcc -E -P and clang -E -P have different behavior. While both don't
generates linemarkers, gcc also removes all empty lines while clang
keep them all. We don't need those empty lines, so we don't generates
them in the final compat/%.h headers. (This replace `uniq` which was
only de-duplicating empty line.)

The only changes in the final generated headers it that they don't
have empty lines anymore.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
---

Notes:
    v4:
    - new patch

 xen/include/Makefile             | 13 ++----------
 xen/tools/compat-build-header.py | 36 ++++++++++++++++++++++++++++++--
 2 files changed, 36 insertions(+), 13 deletions(-)

diff --git a/xen/include/Makefile b/xen/include/Makefile
index 74b26a028902..7e2d0ff667e8 100644
--- a/xen/include/Makefile
+++ b/xen/include/Makefile
@@ -53,20 +53,11 @@ all: $(headers-y)
 xlat_lst = xlat.lst
 
 compat/%.h: compat/%.i Makefile $(BASEDIR)/tools/compat-build-header.py
-	set -e; id=_$$(echo $@ | tr '[:lower:]-/.' '[:upper:]___'); \
-	echo "#ifndef $$id" >$@.new; \
-	echo "#define $$id" >>$@.new; \
-	echo "#include <xen/compat.h>" >>$@.new; \
-	$(if $(filter-out compat/arch-%.h,$@),echo "#include <$(patsubst compat/%,public/%,$@)>" >>$@.new;) \
-	$(if $(prefix-y),echo "$(prefix-y)" >>$@.new;) \
-	grep -v '^# [0-9]' $< | \
-	$(PYTHON) $(BASEDIR)/tools/compat-build-header.py | uniq >>$@.new; \
-	$(if $(suffix-y),echo "$(suffix-y)" >>$@.new;) \
-	echo "#endif /* $$id */" >>$@.new
+	$(PYTHON) $(BASEDIR)/tools/compat-build-header.py <$< $@ "$(prefix-y)" "$(suffix-y)" >>$@.new; \
 	mv -f $@.new $@
 
 compat/%.i: compat/%.c Makefile
-	$(CPP) $(filter-out -Wa$(comma)% -include %/include/xen/config.h,$(XEN_CFLAGS)) $(cppflags-y) -o $@ $<
+	$(CPP) -P $(filter-out -Wa$(comma)% -include %/include/xen/config.h,$(XEN_CFLAGS)) $(cppflags-y) -o $@ $<
 
 compat/%.c: public/%.h $(xlat_lst) Makefile $(BASEDIR)/tools/compat-build-source.py
 	mkdir -p $(@D)
diff --git a/xen/tools/compat-build-header.py b/xen/tools/compat-build-header.py
index b85c43f13faf..d89a900ea02c 100755
--- a/xen/tools/compat-build-header.py
+++ b/xen/tools/compat-build-header.py
@@ -2,6 +2,12 @@
 
 import re,sys
 
+try:
+    type(str.maketrans)
+except AttributeError:
+    # For python2
+    import string as str
+
 pats = [
  [ r"__InClUdE__(.*)", r"#include\1\n#pragma pack(4)" ],
  [ r"__IfDeF__ (XEN_HAVE.*)", r"#ifdef \1" ],
@@ -20,7 +26,33 @@ pats = [
  [ r"(^|[^\w])long([^\w]|$$)", r"\1int\2" ]
 ];
 
+output_filename = sys.argv[1]
+
+# tr '[:lower:]-/.' '[:upper:]___'
+header_id = '_' + \
+    output_filename.upper().translate(str.maketrans('-/.','___'))
+
+header = """#ifndef {0}
+#define {0}
+#include <xen/compat.h>""".format(header_id)
+
+print(header)
+
+if not re.match("compat/arch-.*.h$", output_filename):
+    x = output_filename.replace("compat/","public/")
+    print('#include <%s>' % x)
+
+def print_if_nonempty(s):
+    if len(s):
+        print(s)
+
+print_if_nonempty(sys.argv[2])
+
 for line in sys.stdin.readlines():
     for pat in pats:
-        line = re.subn(pat[0], pat[1], line)[0]
-    print(line.rstrip())
+        line = re.sub(pat[0], pat[1], line.rstrip())
+    print_if_nonempty(line)
+
+print_if_nonempty(sys.argv[3])
+
+print("#endif /* %s */" % header_id)
-- 
Anthony PERARD