Ported upb to C89, for greater portability.

A large part of this change contains surface-level
porting, like moving variable declarations to the
top of the block.

However there are a few more substantial things too:

- moved internal-only struct definitions to a separate
  file (structdefs.int.h), for greater encapsulation
  and ABI compatibility.

- removed the UPB_UPCAST macro, since it requires access
  to the internal-only struct definitions.  Replaced uses
  with calls to inline, type-safe casting functions.

- removed the UPB_DEFINE_CLASS/UPB_DEFINE_STRUCT macros.
  Class and struct definitions are now more explicit -- you
  get to see the actual class/struct keywords in the source.
  The casting convenience functions have been moved into
  UPB_DECLARE_DERIVED_TYPE() and UPB_DECLARE_DERIVED_TYPE2().

- the new way that we duplicate base methods in derived types
  is also more convenient and requires less duplication.
  It is also less greppable, but hopefully that is not
  too big a problem.

Compiler flags (-std=c89 -pedantic) should help to rigorously
enforce that the code is free of C99-isms.

A few functions are not available in C89 (strtoll).  There
are temporary, hacky solutions in place.

1 files changed, 34 insertions, 24 deletions

diff --git a/Makefile b/Makefile
index b3f3d55..d67beb0 100644
--- a/Makefile
+++ b/Makefile
@@ -43,19 +43,23 @@ WITH_JIT=no
 UPB_FAIL_WARNINGS?=no
 
 # Basic compiler/flag setup.
+# We are C89/C++98, with the one exception that we need stdint and "long long."
 CC?=cc
 CXX?=c++
-CFLAGS=-std=c99
-CXXFLAGS=-Wno-unused-private-field
+CFLAGS=
+CXXFLAGS=
 INCLUDE=-I.
+CSTD=-std=c89 -pedantic -Wno-long-long
+CXXSTD=-std=c++98 -pedantic -Wno-long-long
 WARNFLAGS=-Wall -Wextra -Wpointer-arith
-WARNFLAGS_CXX=-Wall -Wextra -Wpointer-arith
+WARNFLAGS_CXX=$(WARNFLAGS) -Wno-unused-private-field
 CPPFLAGS=$(INCLUDE) -DNDEBUG $(USER_CPPFLAGS)
 LUA=lua  # 5.1 and 5.2 should both be supported
 
 ifneq ($(WITH_JIT), no)
   USE_JIT=true
   CPPFLAGS += -DUPB_USE_JIT_X64
+  EXTRA_LIBS += -ldl
 endif
 
 ifeq ($(CC), clang)
@@ -168,11 +172,16 @@ upb_pb_SRCS = \
 # If Lua is present we can use DynASM to regenerate the .h file.
 ifdef USE_JIT
 upb_pb_SRCS += upb/pb/compile_decoder_x64.c
-obj/upb/pb/compile_decoder_x64.o obj/upb/pb/compile_decoder_x64.lo: upb/pb/compile_decoder_x64.h
+
+# The JIT can't compile with -Wpedantic, since it does some inherently
+# platform-specific things like casting between data pointers and function
+# pointers.  Also DynASM emits some GNU extensions.
+obj/upb/pb/compile_decoder_x64.o : CSTD = -std=gnu89
+obj/upb/pb/compile_decoder_x64.lo : CSTD = -std=gnu89
 
 upb/pb/compile_decoder_x64.h: upb/pb/compile_decoder_x64.dasc
 	$(E) DYNASM $<
-	$(Q) $(LUA) dynasm/dynasm.lua upb/pb/compile_decoder_x64.dasc > upb/pb/compile_decoder_x64.h || (rm upb/pb/compile_decoder_x64.h ; false)
+	$(Q) $(LUA) dynasm/dynasm.lua -c upb/pb/compile_decoder_x64.dasc > upb/pb/compile_decoder_x64.h || (rm upb/pb/compile_decoder_x64.h ; false)
 endif
 
 upb_json_SRCS = \
@@ -221,19 +230,19 @@ $(UPB_LIBS): lib/lib%.a: $(call make_objs,o)
 
 obj/upb/%.o: upb/%.c | $$(@D)/.
 	$(E) CC $<
-	$(Q) $(CC) $(OPT) $(WARNFLAGS) $(CPPFLAGS) $(CFLAGS) -c -o $@ $<
+	$(Q) $(CC) $(OPT) $(CSTD) $(WARNFLAGS) $(CPPFLAGS) $(CFLAGS) -c -o $@ $<
 
 obj/upb/%.o: upb/%.cc | $$(@D)/.
 	$(E) CXX $<
-	$(Q) $(CXX) $(OPT) $(WARNFLAGS_CXX) $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $<
+	$(Q) $(CXX) $(OPT) $(CXXSTD) $(WARNFLAGS_CXX) $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $<
 
 obj/upb/%.lo: upb/%.c | $$(@D)/.
 	$(E) 'CC -fPIC' $<
-	$(Q) $(CC) $(OPT) $(WARNFLAGS) $(CPPFLAGS) $(CFLAGS) -c -o $@ $< -fPIC
+	$(Q) $(CC) $(OPT) $(CSTD) $(WARNFLAGS) $(CPPFLAGS) $(CFLAGS) -c -o $@ $< -fPIC
 
 obj/upb/%.lo: upb/%.cc | $$(@D)/.
 	$(E) CXX -fPIC $<
-	$(Q) $(CXX) $(OPT) $(WARNFLAGS_CXX) $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $< -fPIC
+	$(Q) $(CXX) $(OPT) $(CXXSTD) $(WARNFLAGS_CXX) $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $< -fPIC
 
 # Note: mkdir -p is technically susceptible to races when used with make -j.
 %/.:
@@ -246,7 +255,7 @@ upb/descriptor/descriptor.pb: upb/descriptor/descriptor.proto
 
 genfiles: upb/descriptor/descriptor.pb tools/upbc
 	./tools/upbc upb/descriptor/descriptor.pb upb/descriptor/descriptor google_protobuf_descriptor
-	lua dynasm/dynasm.lua upb/pb/compile_decoder_x64.dasc > upb/pb/compile_decoder_x64.h || (rm upb/pb/compile_decoder_x64.h ; false)
+	$(LUA) dynasm/dynasm.lua -c upb/pb/compile_decoder_x64.dasc > upb/pb/compile_decoder_x64.h || (rm upb/pb/compile_decoder_x64.h ; false)
 
 # upbc depends on these Lua extensions.
 UPBC_LUA_EXTS = \
@@ -288,28 +297,28 @@ tests: $(TESTS)
 
 tests/testmain.o: tests/testmain.cc
 	$(E) CXX $<
-	$(Q) $(CXX) $(OPT) $(WARNFLAGS_CXX) $(CXXFLAGS) $(CPPFLAGS) -c -o $@ $<
+	$(Q) $(CXX) $(OPT) $(CXXSTD) $(WARNFLAGS_CXX) $(CXXFLAGS) $(CPPFLAGS) -c -o $@ $<
 
 $(C_TESTS): % : %.c tests/testmain.o $$(LIBS)
 	$(E) CC $<
-	$(Q) $(CC) $(OPT) $(WARNFLAGS) $(CPPFLAGS) $(CFLAGS) -o $@ tests/testmain.o $< $(LIBS)
+	$(Q) $(CC) $(OPT) $(CSTD) $(WARNFLAGS) $(CPPFLAGS) $(CFLAGS) -o $@ tests/testmain.o $< $(LIBS)
 
 $(CC_TESTS): % : %.cc tests/testmain.o $$(LIBS)
 	$(E) CXX $<
-	$(Q) $(CXX) $(OPT) $(WARNFLAGS_CXX) $(CPPFLAGS) $(CXXFLAGS) -Wno-deprecated -o $@ tests/testmain.o $< $(LIBS)
+	$(Q) $(CXX) $(OPT) $(CXXSTD) $(WARNFLAGS_CXX) $(CPPFLAGS) $(CXXFLAGS) -Wno-deprecated -o $@ tests/testmain.o $< $(LIBS)
 
 # Several of these tests don't actually test these libs, but use them
 # incidentally to load a descriptor
 LOAD_DESCRIPTOR_LIBS = lib/libupb.pb.a lib/libupb.descriptor.a
 
 # Specify which libs each test depends on.
-tests/pb/test_varint: LIBS = lib/libupb.pb.a lib/libupb.a
-tests/test_def: LIBS = $(LOAD_DESCRIPTOR_LIBS) lib/libupb.a
-tests/test_handlers: LIBS = lib/libupb.descriptor.a lib/libupb.a
-tests/pb/test_decoder: LIBS = lib/libupb.pb.a lib/libupb.a
-tests/test_cpp: LIBS = $(LOAD_DESCRIPTOR_LIBS) lib/libupb.a
-tests/test_table: LIBS = lib/libupb.a
-tests/json/test_json: LIBS = lib/libupb.a lib/libupb.json.a
+tests/pb/test_varint: LIBS = lib/libupb.pb.a lib/libupb.a $(EXTRA_LIBS)
+tests/test_def: LIBS = $(LOAD_DESCRIPTOR_LIBS) lib/libupb.a $(EXTRA_LIBS)
+tests/test_handlers: LIBS = lib/libupb.descriptor.a lib/libupb.a $(EXTRA_LIBS)
+tests/pb/test_decoder: LIBS = lib/libupb.pb.a lib/libupb.a $(EXTRA_LIBS)
+tests/test_cpp: LIBS = $(LOAD_DESCRIPTOR_LIBS) lib/libupb.a $(EXTRA_LIBS)
+tests/test_table: LIBS = lib/libupb.a $(EXTRA_LIBS)
+tests/json/test_json: LIBS = lib/libupb.a lib/libupb.json.a $(EXTRA_LIBS)
 
 tests/test_def: tests/test.proto.pb
 
@@ -382,7 +391,8 @@ GOOGLEPB_TEST_LIBS = \
   lib/libupb.bindings.googlepb.a \
   lib/libupb.pb.a \
   lib/libupb.descriptor.a \
-  lib/libupb.a
+  lib/libupb.a \
+  $(EXTRA_LIBS)
 
 GOOGLEPB_TEST_DEPS = \
   tests/bindings/googlepb/test_vs_proto2.cc \
@@ -456,15 +466,15 @@ LUA_LIB_DEPS = \
 
 upb/bindings/lua/upb_c.so: upb/bindings/lua/upb.c $(LUA_LIB_DEPS)
 	$(E) CC upb/bindings/lua/upb.c
-	$(Q) $(CC) $(OPT) $(WARNFLAGS) $(CPPFLAGS) $(CFLAGS) -fpic -shared -o $@ $< $(LUA_LDFLAGS) $(LUA_LIB_DEPS)
+	$(Q) $(CC) $(OPT) $(CSTD) $(WARNFLAGS) $(CPPFLAGS) $(CFLAGS) -fpic -shared -o $@ $< $(LUA_LDFLAGS) $(LUA_LIB_DEPS)
 
 upb/bindings/lua/upb/table_c.so: upb/bindings/lua/upb/table.c lib/libupb_pic.a
 	$(E) CC upb/bindings/lua/upb/table.c
-	$(Q) $(CC) $(OPT) $(WARNFLAGS) $(CPPFLAGS) $(CFLAGS) -fpic -shared -o $@ $< $(LUA_LDFLAGS)
+	$(Q) $(CC) $(OPT) $(CSTD) $(WARNFLAGS) $(CPPFLAGS) $(CFLAGS) -fpic -shared -o $@ $< $(LUA_LDFLAGS)
 
 upb/bindings/lua/upb/pb_c.so: upb/bindings/lua/upb/pb.c $(LUA_LIB_DEPS)
 	$(E) CC upb/bindings/lua/upb/pb.c
-	$(Q) $(CC) $(OPT) $(WARNFLAGS) $(CPPFLAGS) $(CFLAGS) -fpic -shared -o $@ $< $(LUA_LDFLAGS)
+	$(Q) $(CC) $(OPT) $(CSTD) $(WARNFLAGS) $(CPPFLAGS) $(CFLAGS) -fpic -shared -o $@ $< $(LUA_LDFLAGS)
 
 
 # Python extension #############################################################