There was a bug in our arena code where we assumed that
sizeof(upb_array) would be a multiple of 8. On i386 it was
not, and this was causing memory corruption on 32-bit builds.
Until everyone can regenerate their code, we need to provide
compatible semantics with the old generated code.
Also fixed a bug where enums were allocated 8 bytes instead
of 4.
* Added -Wextra and -Wshorten-64-to-32 and fixed resulting errors.
* Disable -Wshorten-32-to-64 since Kokoro is missing Clang.
* Fixed -Wextra warnings for gcc.
* Reordered UPB_UNUSED() to come after declarations.
* Added another -pedantic fix and log CC version.
* Fix compile error and conditionally run use_bazel.sh.
* Moved set -e after use_bazel.sh.
* Fixed typo in conditional.
- A new PHP-specific upb amalgamation. It contains everything related to upb_msg, but leaves out all of the old handlers-related interfaces and encoders/decoders.
# Schema/Defs Changes
- Changed `upb_fielddef_msgsubdef()` and `upb_fielddef_enumsubdef()` to return `NULL` instead of assert-failing if the field is not a message or enum.
- Added `upb_msgdef_iswrapper()`, to test whether this is a wrapper well-known type.
# Decoder
- Decoder bugfix: when we parse a submessage inside a oneof, we need to clear out any previous data, so we don't misinterpret it as a pointer to an existing submessage.
# JSON Decoder
- Allowed well-known types at the top level to have their special processing.
- Fixed a bug that could occur when parsing nested empty lists/objects, eg `[[]]`.
- Made the "ignore unknown" option also be permissive about unknown enumerators by setting them to 0.
# JSON Encoder
- Allowed well-known types at the top level to have their special processing.
- Removed all spaces after `:` and `,` characters, to match the old encoder and pass goldenfile tests.
# Message / Reflection
- Changed `upb_msg_hasoneof()` -> `upb_msg_whichoneof()`. The new function returns the `upb_fielddef*` of whichever oneof is set.
- Implemented `upb_msg_clearfield()` and added/implemented `upb_msg_clear()`.
- Added `upb_msg_discardunknown()`. Part of me thinks this should go in a util library instead of core reflection since it is a recursive algorithm.
# Compiler
- Always emit descriptors as an array instead of as a string, to avoid exceeding maximum string lengths. If this becomes a speed issue later we can go back to two separate paths.
* Created amalgamation with upb_msg but no handlers.
* Bugfix for upb_array_resize().
* Renamed "lite" amalgamation to "core", to avoid confusion.
Traditionally "lite" has meant "without reflection", but here we
mean it as "without handlers-based code."
* Build fixes from CI tests.
* Removed some more C++-style comments.
* Fix for out-of-order statements.
* WIP.
* Passes most tests.
* A few fixes.
* A few optimizations.
* Some more optimiation.
* Update Protobuf to v3.11.4 and Abseil to LTS 2020-02-25
* Use longjmp instead of explicit error checks at every level.
* Used macros for better documentation of ops.
* Fixed bug with map parsing. All tests are passing except a few conformance tests.
* Fixed remaining bugs, all conformance tests pass.
Also ported all of upb to a single UPB_PTR_AT() macro instead of
having multiple .c files define their own.
* Formatted with clang-format.
* Fixes to compile on Linux.
* A few more compile fixes.
* Script to benchmark changes.
* Fixed parenthesis bug in op calculation.
* Updated generated descriptor files.
* WIP.
* Removed trailing enum to fix the Linux build.
* Respect packed=false to fix conformance failures in new protobuf version.
* Small simplification.
* Fixes to decoder.
* Removed stray comment.
Co-authored-by: Yannic Bonenberger <contact@yannic-bonenberger.com>
New code is smaller (in both source size and compiled size) and faster.
# Speed
The decoder speeds up on all machines I tested, though the amount of speedup varies. I was only able to test Intel CPUs.
### Linux Desktop
```
CPU: Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz
OS: Linux
name old time/op new time/op delta
CreateArena 4.72ns ± 0% 4.93ns ± 0% +4.47% (p=0.000 n=11+11)
ParseDescriptor 12.4µs ± 1% 9.1µs ± 1% -26.65% (p=0.000 n=11+11)
```
### Mac Laptop
```
CPU: Intel(R) Core(TM) i7-8850H CPU @ 2.60GHz
OS: macOS
name old time/op new time/op delta
CreateArena 5.33ns ± 3% 5.58ns ± 2% +4.69% (p=0.000 n=12+12)
ParseDescriptor 15.0µs ± 2% 11.9µs ± 2% -20.20% (p=0.000 n=12+12)
```
### Linux Workstation
```
CPU: Intel(R) Xeon(R) Gold 6154 CPU @ 3.00GHz
OS: Linux
name old time/op new time/op delta
CreateArena 5.29ns ± 0% 5.52ns ± 0% +4.37% (p=0.000 n=10+12)
ParseDescriptor 18.6µs ± 0% 16.4µs ± 0% -11.54% (p=0.000 n=12+12)
```
# Size
A few source files grow marginally because of some arena functionality moved inline. But `upb/decode.c` shrinks by 30% on Linux:
```
VM SIZE
--------------
+2.1% +283 upb/json_decode.c
+24% +205 upb/msg.c
+8.4% +115 upb/upb.c
+0.9% +28 upb/reflection.c
[ = ] 0 upb/def.c
[ = ] 0 upb/encode.c
[ = ] 0 upb/json_encode.c
[ = ] 0 upb/table.c
-30.3% -1.51Ki upb/decode.c
-0.7% -738 TOTAL
```
Joshua Haberman
Nicolas Noble