- Capture the version used to generated.
- Check at compile time and runtime that generated code isn't from a newer
version, also check that the min version required is also supported.
- Keep the old constants/macros/functions to special case the last version
that was working so those generated sources still work until we decide
otherwise.
Working on https://github.com/google/protobuf/issues/1599, specifically:
- Turn on more warnings that the Xcode UI calls out with individual controls.
- Manually add:
-Wundef
-Wswitch-enum
- Manually add and then diable in the unittests because of XCTest's headers:
-Wreserved-id-macro
-Wdocumentation-unknown-command
- Manually add -Wdirect-ivar-access, but disable it for the unittests and in
the library code (via #pragmas to suppress it). This is done so proto users
can enable the warning.
NOTE: This is a binary breaking change as structure sizes have changed size
and/or order.
- Drop capturing field options, no other options were captured and other mobile
targeted languages don't try to capture this sort information (saved 8
bytes for every field defined (in static data and again in field descriptor
instance size data).
- No longer generate/compile in the messages/enums in descriptor.proto. If
developers need it, they should generate it and compile it in. Reduced the
overhead of the core library.
- Compute the number of has_bits actually needs to avoid over reserving.
- Let the boolean single fields store via a has_bit to avoid storage, makes
the common cases of the instance size smaller.
- Reorder some flags and down size the enums to contain the bits needed.
- Reorder the items in the structures to manually ensure they are are packed
better (especially when generating 64bit code - 8 bytes for every field,
16 bytes for every extension, instance sizes 8 bytes also).
- Split off the structure initialization so when the default is zero, the
generated static storage doesn't need to reserve the space. This is batched
at the message level, so all the fields for the message have to have zero
defaults to get the saves. By definition all proto3 syntax files fall into
this case but it also saves space for the proto2 that use the standard
defaults. (saves 8 bytes of static data for every field that had a zero
default)
- Don't track the enums defined by a message. Nothing in the runtime needs it
and it was just generation and runtime overhead. (saves 8 bytes per enum)
- Ensure EnumDescriptors are started up threadsafe in all cases.
- Split some of the Descriptor initialization into multiple methods so the
generated code isn't padded with lots of zero/nil args.
- Change how oneof info is feed to the runtime enabling us to generate less
static data (8 bytes saved per oneof for 64bit).
- Change how enum value informat is capture to pack the data and only decode
it if it ends up being needed. Avoids padding issues causing bloat of 64bit,
and removes the needs for extra pointers in addition to the data (just the
data and one pointer now).
- Add more to the ObjC dir readme.
- Merge the ExtensionField and ExtensionDescriptor to reduce overhead.
- Fix an initialization race.
- Clean up the Xcode schemes.
- Remove the class/enum filter.
- Remove some forced inline that were bloating things without proof of performance wins.
- Rename some internal types to avoid conflicts with the well know types protos.
- Drop the use of ApplyFunctions to the compiler/optimizer can do what it wants.
- Better document some possible future improvements.
- Add missing support for parsing repeated primitive fields in packed or unpacked forms.
- Improve -hash.
- Add *Count for repeated and map<> fields to avoid auto create when checking for them being set.
