Sync from internal Google development.

Many improvements, too many to mention.  One significant
perf regression warrants investigation:

omitfp.parsetoproto2_googlemessage1.upb_jit: 343 -> 252 (-26.53)
plain.parsetoproto2_googlemessage1.upb_jit: 334 -> 251 (-24.85)

25% regression for this benchmark is bad, but since I don't think
there's any fundamental design issue that caused it I'm going to
go ahead with the commit anyway.  Can investigate and fix later.

Other benchmarks were neutral or showed slight improvement.

1 files changed, 42 insertions, 41 deletions

diff --git a/Makefile b/Makefile
index 6aef581..a12e7ef 100644
--- a/Makefile
+++ b/Makefile
@@ -83,11 +83,15 @@ deps: Makefile $(ALLSRC)
 CORE= \
   upb/upb.c \
   upb/handlers.c \
-  upb/descriptor.c \
+  upb/descriptor/reader.c \
   upb/table.c \
+  upb/refcount.c \
   upb/def.c \
   upb/msg.c \
   upb/bytestream.c \
+  bindings/cpp/upb/proto2_bridge.cc \
+
+# TODO: the proto2 bridge should be built as a separate library.
 
 # Library for the protocol buffer format (both text and binary).
 PB= \
@@ -122,8 +126,9 @@ LIBUPB_PIC=upb/libupb_pic.a
 lib: $(LIBUPB)
 
 
-OBJ=$(patsubst %.c,%.o,$(SRC))
-PICOBJ=$(patsubst %.c,%.lo,$(SRC))
+OBJ=$(patsubst %.c,%.o,$(SRC)) $(patsubst %.cc,%.o,$(SRC))
+PICOBJ=$(patsubst %.c,%.lo,$(SRC)) $(patsubst %.cc,%.lo,$(SRC))
+
 
 ifdef USE_JIT
 upb/pb/decoder.o upb/pb/decoder.lo: upb/pb/decoder_x64.h
@@ -139,10 +144,18 @@ $(LIBUPB_PIC): $(PICOBJ)
 	$(E) CC $<
 	$(Q) $(CC) $(CFLAGS) $(CPPFLAGS) -c -o $@ $<
 
+%.o : %.cc
+	$(E) CXX $<
+	$(Q) $(CXX) $(CXXFLAGS) $(CPPFLAGS) -c -o $@ $<
+
 %.lo : %.c
 	$(E) 'CC -fPIC' $<
 	$(Q) $(CC) $(CFLAGS) $(CPPFLAGS) -c -o $@ $< -fPIC
 
+%.o : %.cc
+	$(E) CXX $<
+	$(Q) $(CXX) $(CXXFLAGS) $(CPPFLAGS) -c -o $@ $< -fPIC
+
 # Override the optimization level for def.o, because it is not in the
 # critical path but gets very large when -O3 is used.
 upb/def.o: upb/def.c
@@ -197,47 +210,39 @@ tests/test.proto.pb: tests/test.proto
 SIMPLE_TESTS= \
   tests/test_def \
   tests/test_varint \
-  tests/tests \
-
-# Too many tests in this binary to run Valgrind (it takes minutes).
-SLOW_TESTS= \
-  tests/test_decoder \
 
 SIMPLE_CXX_TESTS= \
   tests/test_table \
   tests/test_cpp \
+  tests/test_decoder \
 
 VARIADIC_TESTS= \
   tests/t.test_vs_proto2.googlemessage1 \
   tests/t.test_vs_proto2.googlemessage2 \
 
-TESTS=$(SIMPLE_TESTS) $(SIMPLE_CXX_TESTS) $(VARIADIC_TESTS) $(SLOW_TESTS)
-tests: $(TESTS)
+TESTS=$(SIMPLE_TESTS) $(SIMPLE_CXX_TESTS) $(VARIADIC_TESTS)
+
+
+tests: $(TESTS) $(INTERACTIVE_TESTS)
 $(TESTS): $(LIBUPB)
-tests/tests: tests/test.proto.pb
+tests/test_def: tests/test.proto.pb
 
 $(SIMPLE_TESTS): % : %.c
 	$(E) CC $<
 	$(Q) $(CC) $(CFLAGS) $(CPPFLAGS) -o $@ $< $(LIBUPB)
 
-VALGRIND=valgrind --leak-check=full --error-exitcode=1 
+VALGRIND=valgrind --leak-check=full --error-exitcode=1
 test: tests
 	@echo Running all tests under valgrind.
 	@set -e  # Abort on error.
 	@for test in $(SIMPLE_TESTS) $(SIMPLE_CXX_TESTS); do \
 	  if [ -x ./$$test ] ; then \
-	    echo !!! $(VALGRIND) ./$$test tests/test.proto.pb; \
+	    echo !!! $(VALGRIND) ./$$test; \
 	    $(VALGRIND) ./$$test tests/test.proto.pb || exit 1; \
 	  fi \
 	done;
-	@for test in "$(SLOW_TESTS)"; do \
-	  if [ -x ./$$test ] ; then \
-	    echo !!! ./$$test; \
-	    ./$$test || exit 1; \
-	  fi \
-	done;
-	@$(VALGRIND) tests/t.test_vs_proto2.googlemessage1 benchmarks/google_messages.proto.pb benchmarks/google_message1.dat
-	@$(VALGRIND) tests/t.test_vs_proto2.googlemessage2 benchmarks/google_messages.proto.pb benchmarks/google_message2.dat
+	@$(VALGRIND) ./tests/t.test_vs_proto2.googlemessage1 benchmarks/google_message1.dat || exit 1;
+	@$(VALGRIND) ./tests/t.test_vs_proto2.googlemessage2 benchmarks/google_message2.dat || exit 1;
 	@echo "All tests passed!"
 
 tests/t.test_vs_proto2.googlemessage1 \
@@ -273,15 +278,11 @@ tests/tests: upb/libupb.a
 # Benchmarks
 UPB_BENCHMARKS=benchmarks/b.parsestream_googlemessage1.upb_table \
                benchmarks/b.parsestream_googlemessage2.upb_table \
-               benchmarks/b.parsetostruct_googlemessage1.upb_table_byval \
-               benchmarks/b.parsetostruct_googlemessage2.upb_table_byval \
 
 ifdef USE_JIT
 UPB_BENCHMARKS += \
                benchmarks/b.parsestream_googlemessage1.upb_jit \
                benchmarks/b.parsestream_googlemessage2.upb_jit \
-               benchmarks/b.parsetostruct_googlemessage1.upb_jit_byval \
-               benchmarks/b.parsetostruct_googlemessage2.upb_jit_byval \
                benchmarks/b.parsetoproto2_googlemessage1.upb_jit \
                benchmarks/b.parsetoproto2_googlemessage2.upb_jit
 endif
@@ -318,21 +319,21 @@ benchmarks/google_messages.pb.cc: benchmarks/google_messages.proto
 # want to make these command-line parameters -- it makes it more annoying to
 # debug or profile them.
 
-benchmarks/b.parsetostruct_googlemessage1.upb_table_byval \
-benchmarks/b.parsetostruct_googlemessage2.upb_table_byval: \
+benchmarks/b.parsetostruct_googlemessage1.upb_table \
+benchmarks/b.parsetostruct_googlemessage2.upb_table: \
     benchmarks/parsetostruct.upb.c $(LIBUPB) benchmarks/google_messages.proto.pb
-	$(E) 'CC benchmarks/parsetostruct.upb.c (benchmarks.SpeedMessage1, byval, nojit)'
-	$(Q) $(CC) $(CFLAGS) $(CPPFLAGS) -o benchmarks/b.parsetostruct_googlemessage1.upb_table_byval $< \
+	$(E) 'CC benchmarks/parsetostruct.upb.c (benchmarks.SpeedMessage1, nojit)'
+	$(Q) $(CC) $(CFLAGS) $(CPPFLAGS) -o benchmarks/b.parsetostruct_googlemessage1.upb_table $< \
 	  -DMESSAGE_NAME=\"benchmarks.SpeedMessage1\" \
 	  -DMESSAGE_DESCRIPTOR_FILE=\"google_messages.proto.pb\" \
 	  -DMESSAGE_FILE=\"google_message1.dat\" \
-	  -DBYREF=false -DJIT=false $(LIBUPB)
-	$(E) 'CC benchmarks/parsetostruct.upb.c (benchmarks.SpeedMessage2, byref, nojit)'
-	$(Q) $(CC) $(CFLAGS) $(CPPFLAGS) -o benchmarks/b.parsetostruct_googlemessage2.upb_table_byval $< \
+	  -DJIT=false $(LIBUPB)
+	$(E) 'CC benchmarks/parsetostruct.upb.c (benchmarks.SpeedMessage2, nojit)'
+	$(Q) $(CC) $(CFLAGS) $(CPPFLAGS) -o benchmarks/b.parsetostruct_googlemessage2.upb_table $< \
 	  -DMESSAGE_NAME=\"benchmarks.SpeedMessage2\" \
 	  -DMESSAGE_DESCRIPTOR_FILE=\"google_messages.proto.pb\" \
 	  -DMESSAGE_FILE=\"google_message2.dat\" \
-	  -DBYREF=false -DJIT=false $(LIBUPB)
+	  -DJIT=false $(LIBUPB)
 
 benchmarks/b.parsestream_googlemessage1.upb_table \
 benchmarks/b.parsestream_googlemessage2.upb_table: \
@@ -351,21 +352,21 @@ benchmarks/b.parsestream_googlemessage2.upb_table: \
 	  $(LIBUPB)
 
 ifdef USE_JIT
-benchmarks/b.parsetostruct_googlemessage1.upb_jit_byval \
-benchmarks/b.parsetostruct_googlemessage2.upb_jit_byval: \
+benchmarks/b.parsetostruct_googlemessage1.upb_jit \
+benchmarks/b.parsetostruct_googlemessage2.upb_jit: \
     benchmarks/parsetostruct.upb.c $(LIBUPB) benchmarks/google_messages.proto.pb
-	$(E) 'CC benchmarks/parsetostruct.upb.c (benchmarks.SpeedMessage1, byref, jit)'
-	$(Q) $(CC) $(CFLAGS) $(CPPFLAGS) -o benchmarks/b.parsetostruct_googlemessage1.upb_jit_byval $< \
+	$(E) 'CC benchmarks/parsetostruct.upb.c (benchmarks.SpeedMessage1, jit)'
+	$(Q) $(CC) $(CFLAGS) $(CPPFLAGS) -o benchmarks/b.parsetostruct_googlemessage1.upb_jit $< \
 	  -DMESSAGE_NAME=\"benchmarks.SpeedMessage1\" \
 	  -DMESSAGE_DESCRIPTOR_FILE=\"google_messages.proto.pb\" \
 	  -DMESSAGE_FILE=\"google_message1.dat\" -DJIT=true \
-	  -DBYREF=true -DJIT=true $(LIBUPB)
-	$(E) 'CC benchmarks/parsetostruct.upb.c (benchmarks.SpeedMessage2, byval, jit)'
-	$(Q) $(CC) $(CFLAGS) $(CPPFLAGS) -o benchmarks/b.parsetostruct_googlemessage2.upb_jit_byval $< \
+	  -DJIT=true $(LIBUPB)
+	$(E) 'CC benchmarks/parsetostruct.upb.c (benchmarks.SpeedMessage2, jit)'
+	$(Q) $(CC) $(CFLAGS) $(CPPFLAGS) -o benchmarks/b.parsetostruct_googlemessage2.upb_jit $< \
 	  -DMESSAGE_NAME=\"benchmarks.SpeedMessage2\" \
 	  -DMESSAGE_DESCRIPTOR_FILE=\"google_messages.proto.pb\" \
 	  -DMESSAGE_FILE=\"google_message2.dat\" -DJIT=true \
-	  -DBYREF=false -DJIT=true $(LIBUPB)
+	  -DJIT=true $(LIBUPB)
 
 benchmarks/b.parsestream_googlemessage1.upb_jit \
 benchmarks/b.parsestream_googlemessage2.upb_jit: \