Generate Android shared library list automatically

* .gitignore: Ignore new generated files.

* cross/Makefile.in (src/Makefile): Remove leftover
specification of the source Gnulib directory.

* cross/ndk-build/ndk-build.mk.in (NDK_BUILD_READELF): New
variable.

* java/Makefile.in (CONFIG_FILE, ALL_DEPENDENCIES, READELF)
(cf-stamp-1, cf-stamp): New variables and rules; compute the set
of library files in the order of loading and generate a file
with this information.
(ALL_CLASS_FILES): New variable; if builddir is not srcdir,
$($(CONFIG_FILE), $(CLASS_FILES)): Depend on EmacsConfig.java.
add generated files in the build directory.
(classes.dex): Adjust to match.

* java/org/gnu/emacs/EmacsNative.java (EmacsNative)
<static initializer>: Load shared libraries from
EMACS_SHARED_LIBRARIES rather than a hard-coded list.

* m4/ndk-build.m4 (ndk_INIT): Search for readelf...
(ndk_CHECK_MODULES): ...and substitute its path as
NDK_BUILD_READELF.

1 files changed, 85 insertions, 6 deletions

diff --git a/java/Makefile.in b/java/Makefile.in
index 7d732be8f91..bd1938689d5 100644
--- a/java/Makefile.in
+++ b/java/Makefile.in
@@ -83,6 +83,10 @@ RESOURCE_FILES := $(foreach file,$(wildcard $(srcdir)/res/*),	\
 # code.  Instead, it is automatically included by the Java compiler.
 RESOURCE_FILE := $(srcdir)/org/gnu/emacs/R.java
 
+# EmacsConfig.java is a file that holds information regarding the set of
+# shared libraries this binary links to, and similar build variables.
+CONFIG_FILE := $(builddir)/org/gnu/emacs/EmacsConfig.java
+
 # CLASS_FILES is what should actually be built and included in the
 # resulting Emacs executable.  The Java compiler might generate more
 # than one class file for each source file, so this only serves as a
@@ -294,8 +298,72 @@ $(RESOURCE_FILE): $(RESOURCE_FILES)
           -J $(dir $@) -M AndroidManifest.xml           \
           -S $(top_srcdir)/java/res
 
-# Make all class files depend on R.java being built.
-$(CLASS_FILES): $(RESOURCE_FILE)
+# Generate a list of libemacs's dependencies with each item ordered
+# before its dependents for the startup process to load in advance, as
+# older versions of the dynamic linker do not consider these libraries
+# when resolving its imports.  The several following statements are
+# executed from a recursive `make' run after shared libraries are
+# generated.
+
+ALL_DEPENDENCIES :=
+
+ifneq (,$(filter cf-stamp-1,$(MAKECMDGOALS)))
+# Don't be sidetracked by dependencies of shared libraries outside the
+# ndk-build directory.
+define get-dependencies
+$(foreach x, \
+$(and $(wildcard $(top_builddir)/cross/ndk-build/$1.so), \
+      $(shell $(NDK_BUILD_READELF) -d \
+        $(wildcard $(top_builddir)/cross/ndk-build/$1.so) \
+        | sed -n 's/.*(NEEDED).*\[\(.*\.so\)\].*/\1/p')), \
+$(basename $(notdir $(x))))
+endef #get-dependencies
+define resolve-one-dependency
+$(foreach dependency,$(call get-dependencies,$1),\
+  $(if $(findstring "$(dependency)",$(ALL_DEPENDENCIES)),,\
+    $(call resolve-one-dependency,$(basename $(notdir $(dependency)))) \
+    $(eval ALL_DEPENDENCIES := $(ALL_DEPENDENCIES) "$(dependency)",)))
+endef #resolve-one-dependency
+DEPENDENCIES := $(foreach file,$(NDK_BUILD_SHARED),\
+                  $(basename $(notdir $(file))))
+$(foreach file,$(DEPENDENCIES),\
+  $(if $(findstring "$(file)",$(ALL_DEPENDENCIES)),,\
+    $(call resolve-one-dependency,$(file)) \
+    $(eval ALL_DEPENDENCIES := $(ALL_DEPENDENCIES) "$(file)",)))
+endif
+
+# EmacsConfig.java:
+ifeq (${V},1)
+AM_V_EMACSCONFIG =
+else
+AM_V_EMACSCONFIG = @$(info $.  GEN      org/gnu/emacs/EmacsConfig.java)
+endif
+
+.PHONY: cf-stamp-1
+cf-stamp-1:
+        $(AM_V_at) echo 'package org.gnu.emacs;\
+public class EmacsConfig\
+{\
+/* This is a generated file.  Do not edit!  */\
+public static final String[] EMACS_SHARED_LIBRARIES\
+= {$(ALL_DEPENDENCIES)};\
+}' | sed 's/\\//g' > globals.tmp
+        $(AM_V_at) mkdir -p org/gnu/emacs
+        $(AM_V_at) $(top_srcdir)/build-aux/move-if-change \
+                globals.tmp org/gnu/emacs/EmacsConfig.java
+
+# cf-stamp-1 is a phony target invoked in a second `make' instance after
+# all shared libraries are compiled, because the computation of
+# ALL_DEPENDENCIES cannot be postponed until that stage in this instance
+# of Make.
+cf-stamp: $(NDK_BUILD_SHARED) $(CROSS_LIBS)
+        $(AM_V_EMACSCONFIG) $(MAKE) cf-stamp-1
+        $(AM_V_at) touch $@
+$(CONFIG_FILE): cf-stamp; @true
+
+# Make all class files depend on R.java and EmacsConfig.java being
+# built.
+$(CLASS_FILES): $(RESOURCE_FILE) $(CONFIG_FILE)
 
 .SUFFIXES: .java .class
 $(CLASS_FILES) &: $(JAVA_FILES)
@@ -305,13 +373,23 @@ $(CLASS_FILES) &: $(JAVA_FILES)
 # N.B. that find must be called all over again in case javac generated
 # nested classes.
 
+ALL_CLASS_FILES =                               \
+  $(subst $$,\$$,$(shell find $(srcdir) -type f -name *.class))
+
+ifneq ($(builddir),$(srcdir))
+# If the build directory is distinct from the source directory, also
+# include generated class files located there.
+ALL_CLASS_FILES = $(ALL_CLASS_FILES) \
+  $(subst $$,\$$,$(shell find $(builddir) -type f -name *.class))
+endif
+
 classes.dex: $(CLASS_FILES) $(if $(IS_D8_R8), $(srcdir)/proguard.conf)
         $(AM_V_D8) $(D8) --classpath $(ANDROID_JAR)             \
-          $(subst $$,\$$,$(shell find $(srcdir) -type f         \
-            -name *.class)) --output $(builddir)                \
+          $(ALL_CLASS_FILES)                                    \
+          --output $(builddir)                                  \
           --min-api $(ANDROID_MIN_SDK)                          \
           $(if $(filter false,$(ANDROID_DEBUGGABLE)),--release, \
-                --debug) \
+                --debug)                                        \
           $(if $(IS_D8_R8),--pg-conf $(srcdir)/proguard.conf)
 
 # When emacs.keystore expires, regenerate it with:
@@ -345,7 +423,8 @@ TAGS: $(ETAGS) $(tagsfiles)
         $(AM_V_GEN) $(ETAGS) $(tagsfiles)
 
 clean:
-        rm -f *.apk emacs.apk-in *.dex *.unaligned *.class *.idsig
+        rm -f *.apk emacs.apk-in *.dex *.unaligned *.class *.idsig \
+          cf-stamp $(CONFIG_FILE)
         rm -rf install-temp $(RESOURCE_FILE) TAGS
         find . -name '*.class' $(FIND_DELETE)