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, 41 insertions, 37 deletions

diff --git a/tools/dump_cinit.lua b/tools/dump_cinit.lua
index 3742abd..048cb3a 100644
--- a/tools/dump_cinit.lua
+++ b/tools/dump_cinit.lua
@@ -205,25 +205,25 @@ function Dumper:new(linktab)
   return obj
 end
 
--- Dumps a _upb_value, eg:
---   UPB_VALUE_INIT_INT32(5)
+-- Dumps a upb_tabval, eg:
+--   UPB_TABVALUE_INIT(5)
 function Dumper:_value(val, upbtype)
   if type(val) == "nil" then
-    return "UPB__VALUE_INIT_NONE"
+    return "UPB_TABVALUE_EMPTY_INIT"
   elseif type(val) == "number" then
     -- Use upbtype to disambiguate what kind of number it is.
     if upbtype == upbtable.CTYPE_INT32 then
-      return string.format("UPB_VALUE_INIT_INT32(%d)", val)
+      return string.format("UPB_TABVALUE_INT_INIT(%d)", val)
     else
       -- TODO(haberman): add support for these so we can properly support
       -- default values.
       error("Unsupported number type " .. upbtype)
     end
   elseif type(val) == "string" then
-    return string.format('UPB_VALUE_INIT_CONSTPTR("%s")', val)
+    return string.format('UPB_TABVALUE_PTR_INIT("%s")', val)
   else
     -- We take this as an object reference that has an entry in the link table.
-    return string.format("UPB_VALUE_INIT_CONSTPTR(%s)", self.linktab:addr(val))
+    return string.format("UPB_TABVALUE_PTR_INIT(%s)", self.linktab:addr(val))
   end
 end
 
@@ -258,7 +258,7 @@ function Dumper:arrayval(val)
   if val.val then
     return string.format("  %s,\n", self:_value(val.val, val.valtype))
   else
-    return "  UPB_ARRAY_EMPTYENT,\n"
+    return "  UPB_TABVALUE_EMPTY_INIT,\n"
   end
 end
 
@@ -296,9 +296,9 @@ local function gettables(def)
 end
 
 local function emit_file_warning(append)
-  append('// This file was generated by upbc (the upb compiler).\n')
-  append('// Do not edit -- your changes will be discarded when the file is\n')
-  append('// regenerated.\n\n')
+  append('/* This file was generated by upbc (the upb compiler).\n')
+  append(' * Do not edit -- your changes will be discarded when the file is\n')
+  append(' * regenerated. */\n\n')
 end
 
 local function join(...)
@@ -356,7 +356,7 @@ end
 local function end_namespace(package, append)
   local package_components = split(package)
   for i=#package_components,1,-1 do
-    append("}  // namespace %s\n", package_components[i])
+    append("}  /* namespace %s */\n", package_components[i])
   end
 end
 
@@ -426,6 +426,7 @@ local function dump_defs_c(symtab, basename, namespace, append)
   -- Emit forward declarations.
   emit_file_warning(append)
   append('#include "upb/def.h"\n')
+  append('#include "upb/structdefs.int.h"\n')
   append('#include "upb/symtab.h"\n\n')
   append("static const upb_msgdef %s;\n", linktab:cdecl(upb.DEF_MSG))
   append("static const upb_fielddef %s;\n", linktab:cdecl(upb.DEF_FIELD))
@@ -436,7 +437,7 @@ local function dump_defs_c(symtab, basename, namespace, append)
   if not linktab:empty("intentries") then
     append("static const upb_tabent %s;\n", linktab:cdecl("intentries"))
   end
-  append("static const _upb_value %s;\n", linktab:cdecl("arrays"))
+  append("static const upb_tabval %s;\n", linktab:cdecl("arrays"))
   append("\n")
   append("#ifdef UPB_DEBUG_REFS\n")
   append("static upb_inttable reftables[%d];\n", reftable_count)
@@ -456,8 +457,8 @@ local function dump_defs_c(symtab, basename, namespace, append)
     append('  UPB_MSGDEF_INIT("%s", %d, %d, %s, %s,' ..
            '&reftables[%d], &reftables[%d]),\n',
            m:full_name(),
-           m:_selector_count(),
-           m:_submsg_field_count(),
+           upbtable.msgdef_selector_count(m),
+           upbtable.msgdef_submsg_field_count(m),
            dumper:inttable(tables.int),
            dumper:strtable(tables.str),
            reftable, reftable + 1)
@@ -469,7 +470,7 @@ local function dump_defs_c(symtab, basename, namespace, append)
   for f in linktab:objs(upb.DEF_FIELD) do
     local subdef = "NULL"
     if f:has_subdef() then
-      subdef = string.format("UPB_UPCAST(%s)", linktab:addr(f:subdef()))
+      subdef = string.format("(const upb_def*)(%s)", linktab:addr(f:subdef()))
     end
     local intfmt
     if f:type() == upb.TYPE_UINT32 or
@@ -490,7 +491,7 @@ local function dump_defs_c(symtab, basename, namespace, append)
            boolstr(f:istagdelim()), boolstr(f:is_extension()),
            boolstr(f:lazy()), boolstr(f:packed()), f:name(), f:number(),
            linktab:addr(f:containing_type()), subdef,
-           f:_selector_base(), f:index(),
+           upbtable.fielddef_selector_base(f), f:index(),
            reftable, reftable + 1
            )
     reftable = reftable + 2
@@ -529,7 +530,7 @@ local function dump_defs_c(symtab, basename, namespace, append)
     append("};\n\n");
   end
 
-  append("static const _upb_value %s = {\n", linktab:cdecl("arrays"))
+  append("static const upb_tabval %s = {\n", linktab:cdecl("arrays"))
   for ent in linktab:objs("arrays") do
     append(dumper:arrayval(ent))
   end
@@ -602,9 +603,14 @@ local function dump_enum_vals(enumdef, append)
   --
   -- (notice the duplicated "TYPE").
   local cident = to_cident(getpackage(enumdef:full_name()))
-  for _, pair in ipairs(enum_vals) do
+  for i, pair in ipairs(enum_vals) do
     k, v = pair[1], pair[2]
-    append('  %s = %d,\n', to_preproc(cident, k), v)
+    append('  %s = %d', to_preproc(cident, k), v)
+    if i == #enum_vals then
+      append('\n')
+    else
+      append(',\n')
+    end
   end
 end
 
@@ -644,7 +650,7 @@ local function dump_selectors(msgdef, append, base)
   --
   -- // So instead we make the latter the very beautiful:
   --   SEL_GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_INT32
-  append("// %s\n", msgdef:full_name())
+  append("/* %s */\n", msgdef:full_name())
   local cident = to_cident(msgdef:full_name())
   for _, pair in ipairs(selectors) do
     k, v = pair[1], pair[2]
@@ -655,19 +661,19 @@ end
 
 local function dump_defs_h(symtab, basename, namespace, append, linktab)
   local basename_preproc = to_preproc(basename)
-  append("// This file contains accessors for a set of compiled-in defs.\n")
-  append("// Note that unlike Google's protobuf, it does *not* define\n")
-  append("// generated classes or any other kind of data structure for\n")
-  append("// actually storing protobufs.  It only contains *defs* which\n")
-  append("// let you reflect over a protobuf *schema*.\n")
-  append("//\n")
+  append("/* This file contains accessors for a set of compiled-in defs.\n")
+  append(" * Note that unlike Google's protobuf, it does *not* define\n")
+  append(" * generated classes or any other kind of data structure for\n")
+  append(" * actually storing protobufs.  It only contains *defs* which\n")
+  append(" * let you reflect over a protobuf *schema*.\n")
+  append(" */\n")
   emit_file_warning(append)
   append('#ifndef %s_UPB_H_\n', basename_preproc)
   append('#define %s_UPB_H_\n\n', basename_preproc)
   append('#include "upb/def.h"\n')
   append('#include "upb/symtab.h"\n\n')
   append('#ifdef __cplusplus\n')
-  append('extern "C" {\n')
+  append('UPB_BEGIN_EXTERN_C\n')
   append('#endif\n\n')
 
   local packages = {}
@@ -681,7 +687,7 @@ local function dump_defs_h(symtab, basename, namespace, append, linktab)
 
   -- Dump C enums for proto enums.
 
-  append("// Enums\n\n")
+  append("/* Enums */\n\n")
   for _, def in ipairs(sorted_defs(symtab:defs(upb.DEF_ENUM))) do
     local cident = to_cident(def:full_name())
     append('typedef enum {\n')
@@ -690,7 +696,7 @@ local function dump_defs_h(symtab, basename, namespace, append, linktab)
   end
 
   -- selectors
-  append("// Selectors\n\n")
+  append("/* Selectors */\n\n")
   for _, def in ipairs(sorted_defs(symtab:defs(upb.DEF_MSG))) do
     dump_selectors(def, append, upb)
   end
@@ -698,7 +704,7 @@ local function dump_defs_h(symtab, basename, namespace, append, linktab)
   append("const upb_symtab *%s_%s(const void *owner);" ..
          "\n\n", namespace, to_cident(basename))
 
-  append("// MessageDefs\n")
+  append("/* MessageDefs */\n")
   dump_defs_for_type(
       "UPB_INLINE const upb_msgdef *%s_%s(const upb_symtab *s) {\n" ..
       "  const upb_msgdef *m = upb_symtab_lookupmsg(s, \"%s\");\n" ..
@@ -710,7 +716,7 @@ local function dump_defs_h(symtab, basename, namespace, append, linktab)
 
   append("\n")
 
-  append("// EnumDefs\n")
+  append("/* EnumDefs */\n")
   dump_defs_for_type(
       "UPB_INLINE const upb_enumdef *%s_%s(const upb_symtab *s) {\n" ..
       "  const upb_enumdef *e = upb_symtab_lookupenum(s, \"%s\");\n" ..
@@ -739,9 +745,7 @@ local function dump_defs_h(symtab, basename, namespace, append, linktab)
   end
 
   append("\n")
-  append('#ifdef __cplusplus\n')
-  append('};  // extern "C"\n')
-  append('#endif\n\n')
+  append('UPB_END_EXTERN_C\n\n')
   append("#ifdef __cplusplus\n\n")
 
   append("namespace %s {\n", namespace)
@@ -794,12 +798,12 @@ local function dump_defs_h(symtab, basename, namespace, append, linktab)
     append("\n")
   end
 
-  append("}  // namespace %s\n\n\n", namespace)
+  append("}  /* namespace %s */\n\n\n", namespace)
 
   append("#undef RETURN_REFFED\n")
-  append("#endif // __cplusplus\n\n")
+  append("#endif /* __cplusplus */\n\n")
 
-  append('#endif  // %s_UPB_H_\n', basename_preproc)
+  append('#endif  /* %s_UPB_H_ */\n', basename_preproc)
 end
 
 function export.dump_defs(symtab, basename, append_h, append_c)