8331886: Allow markdown src file overrides

Reviewed-by: ihse

make/Docs.gmk

@@ -681,13 +681,11 @@ ifeq ($(ENABLE_PANDOC), true)
       $(TOPDIR)/make/jdk/src/classes/build/tools/pandocfilter)
 
   $(foreach m, $(ALL_MODULES), \
-    $(eval MAN_$m := $(call FindModuleManDirs, $m)) \
-    $(foreach d, $(MAN_$m), \
-      $(foreach f, $(call ApplySpecFilter, $(filter %.md, $(call FindFiles, $d))), \
-        $(eval $m_$f_NAME := MAN_TO_HTML_$m_$(strip $(call RelativePath, $f, $(TOPDIR)))) \
-        $(eval $(call SetupProcessMarkdown, $($m_$f_NAME), \
-            SRC := $d, \
-            FILES := $f, \
+    $(eval MAN_$m := $(call ApplySpecFilter, $(filter %.md, $(call FindFiles, \
+          $(call FindModuleManDirs, $m))))) \
+    $(if $(MAN_$m), \
+      $(eval $(call SetupProcessMarkdown, MAN_TO_HTML_$m, \
+        FILES := $(MAN_$m), \
         DEST := $(DOCS_OUTPUTDIR)/specs/man, \
         FILTER := $(PANDOC_HTML_MANPAGE_FILTER), \
         CSS := $(GLOBAL_SPECS_DEFAULT_CSS_FILE), \
@@ -701,8 +699,7 @@ ifeq ($(ENABLE_PANDOC), true)
         EXTRA_DEPS := $(PANDOC_HTML_MANPAGE_FILTER) \
             $(PANDOC_HTML_MANPAGE_FILTER_SOURCE), \
       )) \
-        $(eval JDK_SPECS_TARGETS += $($($m_$f_NAME))) \
-      ) \
+      $(eval JDK_SPECS_TARGETS += $(MAN_TO_HTML_$m)) \
     ) \
   )
 

make/common/ProcessMarkdown.gmk

@@ -38,6 +38,11 @@ define ProcessMarkdown
   $1_$2_INPUT_FILE := $3/$2
   $1_$2_MARKER := $$(subst /,_,$1_$2)
 
+  # Only continue if this target file hasn't been processed already. This lets
+  # the first found source file override any other with the same name.
+  ifeq ($$($1_$2_OUTPUT_FILE_PROCESSED), )
+    $1_$2_OUTPUT_FILE_PROCESSED := true
+
     ifneq ($$($1_REPLACEMENTS), )
       $1_$2_PANDOC_INPUT := $$(SUPPORT_OUTPUTDIR)/markdown/$$($1_$2_MARKER)_pre.tmp
 
@@ -107,6 +112,7 @@ define ProcessMarkdown
     endif
 
     $1 += $$($1_$2_OUTPUT_FILE)
+  endif
 endef
 
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