improvements to iwyudummy target

- split awk script into separate file
- make awk work on older awk version
- create new target in main Makefile.in to generate
  iwyudummy Makefile so we don't have to manually uncomment
  stuff
- exclude /usr includes from the generated makefile
- disable unused macros warnings to reduce noise
- add some sanity checking - prevent using the generated
  makefile with compiler-plugins enabled
- add new target for generating iwyu Makefile so we don't
  need to edit the Makefile when using it

Change-Id: I4af8eb7d1aa5419e546acb9ef905a0fe623db57d
Reviewed-on: https://gerrit.libreoffice.org/12980Reviewed-by: Michael Stahl <mstahl@redhat.com>
Tested-by: Michael Stahl <mstahl@redhat.com>

Makefile.in

@@ -63,9 +63,11 @@ PARALLELISM_OPTION := $(if $(filter-out 0,$(PARALLELISM)),-j $(PARALLELISM),)
 IWYU_OPTION := $(if $(IWYU_PATH),-k CC=$(IWYU_PATH) CXX=$(IWYU_PATH),)
 
 iwyudummy: bootstrap fetch
-	# $(SRCDIR)/bin/gen-iwyu-dummy-lib
 	cd $(BUILDDIR)/iwyudummy && $(MAKE) $(IWYU_OPTION) $(GMAKE_OPTIONS)
 
+iwyudummy.generate:
+	$(SRCDIR)/bin/gen-iwyu-dummy-lib
+
 #
 # Partial Build
 #

bin/gen-iwyu-dummy-lib

@@ -16,11 +16,15 @@
 
 set -e
 
-iwyu_INCLUDES=$(grep -h -r ":$" ${BUILDDIR}/workdir/Dep/*Object* | grep -v 'workdir\|config_host' | sed -e "s,^${SRCDIR}/,," | sed -e "s/:$//"  | sort -u)
+iwyu_INCLUDES=$(grep -h -r ":$" ${BUILDDIR}/workdir/Dep/*Object* \
+    | grep -v 'workdir\|config_host' | grep -v "^/usr" \
+    | sed -e "s,^${SRCDIR}/,," | sed -e "s/:$//"  | sort -u)
 
 iwyu_INCLUDEDIRS=$(echo "${iwyu_INCLUDES}" | sed -e "s,/[^/]*$,," | grep -v "^include" | sort -u)
 
-iwyu_EXTERNALS=$(ls ${SRCDIR}/*/*Library*mk ${SRCDIR}/*/*Executable*mk | xargs awk 'BEGIN {domatch=0;} /))/ {domatch=0;} domatch { if (!($1 in exts)) {exts[$1]; print $1;} } /use_external(s)?,/ { if (index($0, "))")) { gsub(/.*,/, ""); gsub(/)+/, ""); if (!($0 in exts)) {exts[$0]; print $0; } } else { domatch=1;} }' | grep -v '$(\|)\|tde\|expat_x64\|zlib_x64\|mozilla\|apr\|serf')
+iwyu_EXTERNALS=$(ls ${SRCDIR}/*/*Library*mk ${SRCDIR}/*/*Executable*mk \
+    | xargs awk -f bin/gen-iwyu-dummy-lib.awk \
+    | grep -v '$(\|)\|tde\|expat_x64\|zlib_x64\|mozilla\|apr\|serf')
 
 mkdir -p ${BUILDDIR}/iwyudummy
 iwyu_MOD=${BUILDDIR}/iwyudummy/Module_iwyudummy.mk
@@ -31,9 +35,14 @@ echo "include ${SRCDIR}/solenv/gbuild/partial_build.mk" >> ${BUILDDIR}/iwyudummy
 echo '$(eval $(call gb_Module_Module,iwyudummy))' > ${iwyu_MOD}
 echo '$(eval $(call gb_Module_add_targets,iwyudummy,StaticLibrary_iwyudummy))' >> ${iwyu_MOD}
 
+# prevent some common configuration errors
+echo 'ifneq ($(COMPILER_PLUGINS),)' > ${iwyu_LIB}
+echo '    $(call gb_Output_error,--enable-compiler-plugins does not work well with this: bailing out)' > ${iwyu_LIB}
+echo 'endif' > ${iwyu_LIB}
+
 echo '$(eval $(call gb_StaticLibrary_StaticLibrary,iwyudummy))' > ${iwyu_LIB}
 # clang will "compile" headers to .gch by default
-echo '$(eval $(call gb_StaticLibrary_add_cxxflags,iwyudummy,-x c++))' >> ${iwyu_LIB}
+echo '$(eval $(call gb_StaticLibrary_add_cxxflags,iwyudummy,-x c++ -Wno-unused-macros))' >> ${iwyu_LIB}
 echo '$(eval $(call gb_StaticLibrary_use_custom_headers,iwyudummy,officecfg/registry))' >> ${iwyu_LIB}
 echo '$(eval $(call gb_StaticLibrary_use_sdk_api,iwyudummy))' >> ${iwyu_LIB}
 echo '$(eval $(call gb_StaticLibrary_use_externals,iwyudummy,\' >> ${iwyu_LIB}

bin/gen-iwyu-dummy-lib.awk

+BEGIN  { domatch = 0; }
+
+{
+    if ($0 ~ /use_external(s)?,/ )
+    {
+        if (index($0, "))"))
+        {
+            gsub(/.*,/, "");
+            gsub(/\)+/, ""); 
+            if (!($0 in exts))
+            {
+                exts[$0];
+                print $0;
+            }
+        }
+        else
+        {
+           domatch = 1;
+        }
+    }
+    else if ($0 ~ /\)\)/ )
+    {
+        domatch = 0;
+    }
+    else if (domatch == 1)
+    {
+        if (!($1 in exts))
+        {
+            exts[$1];
+            print $1;
+        }
+    }
+}
+