Resolve compilation errors if compiled with more stringent semantic checks.

Adding Travis test to build with strict warnings.
Fixing a warning in a test which used signed/unsigned integer comparison.

.travis.yml

@@ -10,3 +10,4 @@ env:
   - UPB_TRAVIS_BUILD=withprotobuf
   - UPB_TRAVIS_BUILD=lua
   - UPB_TRAVIS_BUILD=coverage
+  - UPB_TRAVIS_BUILD=warnings

Makefile

@@ -38,6 +38,10 @@ USER_CPPFLAGS=
 # Build with "make WITH_JIT=yes" (or anything besides "no") to enable the JIT.
 WITH_JIT=no
 
+# Build with "make WITH_MAX_WARNINGS=yes" (or anything besides "no") to enable
+# with strict warnings and treat warnings as errors.
+WITH_MAX_WARNINGS=no
+
 # Basic compiler/flag setup.
 CC=cc
 CXX=c++
@@ -53,6 +57,10 @@ ifneq ($(WITH_JIT), no)
   CPPFLAGS += -DUPB_USE_JIT_X64
 endif
 
+ifneq ($(WITH_MAX_WARNINGS), no)
+  WARNFLAGS=-Wall -Wextra -Wpointer-arith -Werror
+endif
+
 # Build with "make Q=" to see all commands that are being executed.
 Q=@
 

tests/json/test_json.cc

@@ -347,7 +347,7 @@ void test_json_roundtrip() {
         test_case->input :
         test_case->expected;
 
-    for (int i = 0; i < strlen(test_case->input); i++) {
+    for (size_t i = 0; i < strlen(test_case->input); i++) {
       test_json_roundtrip_message(test_case->input, expected,
                                   serialize_handlers.get(), i);
     }

travis.sh

@@ -28,6 +28,16 @@ withprotobuf_script() {
   make test
 }
 
+# Build with strict warnings.
+warnings_install() {
+  :
+}
+warnings_script() {
+  make -j12 default WITH_MAX_WARNINGS=yes
+  make -j12 tests WITH_MAX_WARNINGS=yes
+  make test
+}
+
 # A 32-bit build.  Can only test the core because any dependencies
 # need to be available as 32-bit libs also, which gets hairy fast.
 # Can't enable the JIT because it only supports x64.

upb/handlers.c

@@ -574,7 +574,7 @@ bool upb_handlers_getselector(const upb_fielddef *f, upb_handlertype_t type,
       *s = f->selector_base;
       break;
   }
-  assert(*s < upb_fielddef_containingtype(f)->selector_count);
+  assert((size_t)*s < upb_fielddef_containingtype(f)->selector_count);
   return true;
 }
 

upb/json/parser.c

@@ -1135,8 +1135,6 @@ static const char _json_trans_actions[] = {
 };
 
 static const int json_start = 1;
-static const int json_first_final = 56;
-static const int json_error = 0;
 
 static const int json_en_number_machine = 10;
 static const int json_en_string_machine = 19;
@@ -1164,7 +1162,7 @@ size_t parse(void *closure, const void *hd, const char *buf, size_t size,
   capture_resume(parser, buf);
 
   
-#line 1168 "upb/json/parser.c"
+#line 1166 "upb/json/parser.c"
 	{
 	int _klen;
 	unsigned int _trans;
@@ -1350,7 +1348,7 @@ _match:
 #line 1082 "upb/json/parser.rl"
 	{ p--; {cs = stack[--top]; goto _again;} }
 	break;
-#line 1354 "upb/json/parser.c"
+#line 1352 "upb/json/parser.c"
 		}
 	}
 
@@ -1382,6 +1380,13 @@ error:
 bool end(void *closure, const void *hd) {
   UPB_UNUSED(closure);
   UPB_UNUSED(hd);
+
+  // Prevent compile warning on unused static constants.
+  UPB_UNUSED(json_start);
+  UPB_UNUSED(json_en_number_machine);
+  UPB_UNUSED(json_en_string_machine);
+  UPB_UNUSED(json_en_value_machine);
+  UPB_UNUSED(json_en_main);
   return true;
 }
 
@@ -1414,13 +1419,13 @@ void upb_json_parser_reset(upb_json_parser *p) {
   int top;
   // Emit Ragel initialization of the parser.
   
-#line 1418 "upb/json/parser.c"
+#line 1423 "upb/json/parser.c"
 	{
 	cs = json_start;
 	top = 0;
 	}
 
-#line 1157 "upb/json/parser.rl"
+#line 1164 "upb/json/parser.rl"
   p->current_state = cs;
   p->parser_top = top;
   accumulate_clear(p);

upb/json/parser.rl

@@ -1084,7 +1084,7 @@ static void end_object(upb_json_parser *p) {
   main := ws object ws;
 }%%
 
-%% write data;
+%% write data noerror nofinal;
 
 size_t parse(void *closure, const void *hd, const char *buf, size_t size,
              const upb_bufhandle *handle) {
@@ -1122,6 +1122,13 @@ error:
 bool end(void *closure, const void *hd) {
   UPB_UNUSED(closure);
   UPB_UNUSED(hd);
+
+  // Prevent compile warning on unused static constants.
+  UPB_UNUSED(json_start);
+  UPB_UNUSED(json_en_number_machine);
+  UPB_UNUSED(json_en_string_machine);
+  UPB_UNUSED(json_en_value_machine);
+  UPB_UNUSED(json_en_main);
   return true;
 }
 

upb/json/printer.c

@@ -162,7 +162,7 @@ static bool putkey(void *closure, const void *handler_data) {
   return true;
 }
 
-#define CHKFMT(val) if ((val) == -1) return false;
+#define CHKFMT(val) if ((val) == (size_t)-1) return false;
 #define CHK(val)    if (!(val)) return false;
 
 #define TYPE_HANDLERS(type, fmt_func)                                        \

upb/pb/decoder.c

@@ -124,7 +124,7 @@ static bool in_residual_buf(const upb_pbdecoder *d, const char *p) {
 // and the parsing stack, so must be called whenever either is updated.
 static void set_delim_end(upb_pbdecoder *d) {
   size_t delim_ofs = d->top->end_ofs - d->bufstart_ofs;
-  if (delim_ofs <= (d->end - d->buf)) {
+  if (delim_ofs <= (size_t)(d->end - d->buf)) {
     d->delim_end = d->buf + delim_ofs;
     d->data_end = d->delim_end;
   } else {
@@ -268,7 +268,7 @@ static NOINLINE int32_t getbytes_slow(upb_pbdecoder *d, void *buf,
     advancetobuf(d, d->buf_param, d->size_param);
   }
   if (curbufleft(d) >= bytes) {
-    consumebytes(d, buf + avail, bytes);
+    consumebytes(d, (char *)buf + avail, bytes);
     return DECODE_OK;
   } else if (d->data_end == d->delim_end) {
     seterr(d, "Submessage ended in the middle of a value or group");
@@ -296,7 +296,7 @@ static NOINLINE size_t peekbytes_slow(upb_pbdecoder *d, void *buf,
   memcpy(buf, d->ptr, ret);
   if (in_residual_buf(d, d->ptr)) {
     size_t copy = UPB_MIN(bytes - ret, d->size_param);
-    memcpy(buf + ret, d->buf_param, copy);
+    memcpy((char *)buf + ret, d->buf_param, copy);
     ret += copy;
   }
   return ret;

upb/pb/encoder.c

@@ -79,7 +79,7 @@ static upb_pb_encoder_segment *top(upb_pb_encoder *e) {
 // Call to ensure that at least "bytes" bytes are available for writing at
 // e->ptr.  Returns false if the bytes could not be allocated.
 static bool reserve(upb_pb_encoder *e, size_t bytes) {
-  if ((e->limit - e->ptr) < bytes) {
+  if ((size_t)(e->limit - e->ptr) < bytes) {
     size_t needed = bytes + (e->ptr - e->buf);
     size_t old_size = e->limit - e->buf;
     size_t new_size = old_size;
@@ -110,7 +110,7 @@ static bool reserve(upb_pb_encoder *e, size_t bytes) {
 // Call when "bytes" bytes have been writte at e->ptr.  The caller *must* have
 // previously called reserve() with at least this many bytes.
 static void encoder_advance(upb_pb_encoder *e, size_t bytes) {
-  assert((e->limit - e->ptr) >= bytes);
+  assert((size_t)(e->limit - e->ptr) >= bytes);
   e->ptr += bytes;
 }
 

upb/table.c

@@ -542,7 +542,7 @@ void upb_inttable_compact(upb_inttable *t) {
     counts[log2ceil(key)]++;
   }
 
-  int arr_size;
+  size_t arr_size = 1;
   int arr_count = upb_inttable_count(t);
 
   if (upb_inttable_count(t) >= max_key * MIN_DENSITY) {