[Docs] Split Doxygen into multiple subprojects

This is done, because multiple PAL implementations necessarily have
common function names.

Documentation/Doxyfile

@@ -1,5 +1,4 @@
-PROJECT_NAME = "Graphene"
-OUTPUT_DIRECTORY = _build/doxygen
+# This is a common Doxyfile, actual listings are built from Doxyfile-*
 
 GENERATE_XML = YES
 XML_PROGRAMLISTING = NO
@@ -8,18 +7,6 @@ XML_OUTPUT = xml
 GENERATE_HTML = NO
 GENERATE_LATEX = NO
 
-RECURSIVE = YES
-INPUT = \
-    ../Pal \
-    ../LibOS/shim/include \
-    ../LibOS/shim/src
-
-EXCLUDE = \
-    ../Pal/lib \
-    ../Pal/regression \
-    ../Pal/test
-#EXCLUDE_PATTERNS =
-
 WARN_NO_PARAMDOC = YES
 WARN_AS_ERROR = NO
 OPTIMIZE_OUTPUT_FOR_C = YES

Documentation/Doxyfile-libos

@@ -0,0 +1,6 @@
+@INCLUDE = Doxyfile
+PROJECT_NAME = "LibOS"
+OUTPUT_DIRECTORY = _build/doxygen-libos
+INPUT = \
+    ../LibOS/shim/include \
+    ../LibOS/shim/src

Documentation/Doxyfile-pal

@@ -0,0 +1,8 @@
+@INCLUDE = Doxyfile
+PROJECT_NAME = "PAL"
+OUTPUT_DIRECTORY = _build/doxygen-pal
+INPUT = ../Pal/include/pal ../Pal/src
+EXCLUDE = ../Pal/src/host
+MACRO_EXPANSION = YES
+EXPAND_ONLY_PREDEF = YES
+PREDEFINED = noreturn=

Documentation/Doxyfile-pal-linux

@@ -0,0 +1,4 @@
+@INCLUDE = Doxyfile
+PROJECT_NAME = "PAL Linux"
+OUTPUT_DIRECTORY = _build/doxygen-pal-linux
+INPUT = ../Pal/src/host/Linux

Documentation/Doxyfile-pal-linux-sgx

@@ -0,0 +1,4 @@
+@INCLUDE = Doxyfile
+PROJECT_NAME = "PAL Linux-SGX"
+OUTPUT_DIRECTORY = _build/doxygen-pal-linux-sgx
+INPUT = ../Pal/src/host/Linux-SGX

Documentation/Makefile

@@ -18,5 +18,5 @@ clean:
 
 # Catch-all target: route all unknown targets to Sphinx using the new
 # "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
-%: Makefile Doxyfile
+%: Makefile
 	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)

Documentation/conf.py

@@ -84,11 +84,12 @@
    :trim:
 '''
 
-breathe_default_project = 'graphene'
-breathe_projects = {breathe_default_project: '_build/doxygen/xml'}
+breathe_projects = {p: '_build/doxygen-{}/xml'.format(p)
+    for p in ('libos', 'pal', 'pal-linux', 'pal-linux-sgx')}
 
 def generate_doxygen(app):
-    subprocess.check_call(['doxygen', 'Doxyfile'])
+    for p in breathe_projects:
+        subprocess.check_call(['doxygen', 'Doxyfile-{}'.format(p)])
 def setup(app):
     app.connect('builder-inited', generate_doxygen)
 

Documentation/libos/shim-init.rst

@@ -8,3 +8,4 @@ A random file documentation
 There is a |~| random function:
 
 .. doxygenfunction:: parse_int
+   :project: libos