This check enforces that each C++ build target has the correct dependencies for
all headers that it includes. We have many targets that were not correct with
respect to this check, so I fixed them up.
I also cleaned up the C++ targets related to the well-known types. I created a
cc_proto_library() target for each one and removed the :wkt_cc_protos target,
since this was necessary to satisfy the layering check. I deleted the
//src/google/protobuf:protobuf_nowkt target and deprecated :protobuf_nowkt,
because the distinction between the :protobuf and :protobuf_nowkt targets was
not really correct. Neither one exposed the headers for the well-known types in
a way that was valid with respect to the layering check, and the idea of
bundling all the well-known types together is not idiomatic in Bazel anyway.
This is a breaking change, because the //:protobuf target no longer bundles the
well-known types. From now on they should be accessed through the new
//:*_cc_proto aliases in our top-level package.
I renamed the :port_def target to :port, which simplifies things a bit by
matching our internal name.
The original motivation for this change was that to move utf8_range onto our CI
infrastructure, we needed to make its dependency rules_fuzzing compatible with
Bazel 6. The rules_fuzzing project builds with the layering check, and I found
that the process of upgrading it to Bazel 6 made it take a dependency on
protobuf, which caused it to break due to layering violations. I was able to
work around this, but it would still be nice to comply with the layering check
so that we don't have to worry about this kind of thing in the future.
PiperOrigin-RevId: 595516736
If the underlying array for a repeated field is a nullptr (which is possible for const array access on a message field that hasn't been set) the begin iterator will currently contain garbage data, which can lead to an illegal access. This CL adds a nullptr check to `begin()`, similar to what already exists for `size()`.
PiperOrigin-RevId: 595217999
To satisfy the layering check, we need to depend on :gtest for the headers, in
addition to :gtest_main which provides the main() function.
There are a bunch of formatting changes as a side effect of this, but they
should be harmless.
PiperOrigin-RevId: 594318263
This makes the file layout a bit more consistent with the `protos ->
protos_generator` pattern. I also replaced the `upbc` namespace with
`upb::generator`.
PiperOrigin-RevId: 569264372
This change moves almost everything in the `upb/` directory up one level, so
that for example `upb/upb/generated_code_support.h` becomes just
`upb/generated_code_support.h`. The only exceptions I made to this were that I
left `upb/cmake` and `upb/BUILD` where they are, mostly because that avoids
conflict with other files and the current locations seem reasonable for now.
The `python/` directory is a little bit of a challenge because we had to merge
the existing directory there with `upb/python/`. I made `upb/python/BUILD` into
the BUILD file for the merged directory, and it effectively loads the contents
of the other BUILD file via `python/build_targets.bzl`, but I plan to clean
this up soon.
PiperOrigin-RevId: 568651768
- Add reference proxy type and change the scalar iterator to interact with it
- Add missing Iterator<T> -> Iterator<const T> conversion
- Add unit tests for reference and iterator types
- Add missing typedefs
- Add missing crbegin/crend functions
PiperOrigin-RevId: 544751376
Update signatures to use T* Ptr<T> consistently.
Cross language blocks utility updated to use GetArena(T*)
Fixes arena_ for Proxy/CProxy ::Access class now consistently fills in arena_ (where message was created in).
PiperOrigin-RevId: 543457599
I recently ran into an issue with public imports and the `protos` generator.
The includes of fwd.h files are currently generated based on where the message
or extension is defined, but when public imports are involved, this fwd.h
header might not be in the direct dependencies. When the `#include` points to a
transitive dependency then this can result in a layering violation.
This CL fixes the problem by generating fwd.h includes for all direct
dependencies, and making sure the fwd.h files themselves contain `#include`
lines to export their public dependencies.
PiperOrigin-RevId: 540102455
Note: Code looks duplicated but in C case, it is for performance. For C++,
C++ and C may diverge in the future for certain methods.
PiperOrigin-RevId: 525826831
This CL changes the upb compiler to no longer depend on C++ protobuf libraries. upb now uses its own reflection libraries to implement its code generator.
# Key Benefits
1. upb can now use its own reflection libraries throughout the compiler. This makes upb more consistent and principled, and gives us more chances to dogfood our own C++ reflection API. This highlighted several parts of the C++ reflection API that were incomplete.
2. This CL removes code duplication that previously existed in the compiler. The upb reflection library has code to build MiniDescriptors and MiniTables out of descriptors, but prior to this CL the upb compiler could not use it. The upb compiler had a separate copy of this logic, and the compiler's copy of this logic was especially tricky and hard to maintain. This CL removes the separate copy of that logic.
3. This CL (mostly) removes upb's dependency on the C++ protobuf library. We still depend on `protoc` (the binary), but the runtime and compiler no longer link against C++'s libraries. This opens up the possibility of speeding up some builds significantly if we can use a prebuilt `protoc` binary.
# Bootstrap Stages
To bootstrap, we check in a copy of our generated code for `descriptor.proto` and `plugin.proto`. This allows the compiler to depend on the generated code for these two protos without creating a circular dependency. This code is checked in to the `stage0` directory.
The bootstrapping process is divided into a few stages. All `cc_library()`, `upb_proto_library()`, and `cc_binary()` targets that would otherwise be circular participate in this staging process. That currently includes:
* `//third_party/upb:descriptor_upb_proto`
* `//third_party/upb:plugin_upb_proto`
* `//third_party/upb:reflection`
* `//third_party/upb:reflection_internal`
* `//third_party/upbc:common`
* `//third_party/upbc:file_layout`
* `//third_party/upbc:plugin`
* `//third_party/upbc:protoc-gen-upb`
For each of these targets, we produce a rule for each stage (the logic for this is nicely encapsulated in Blaze/Bazel macros like `bootstrap_cc_library()` and `bootstrap_upb_proto_library()`, so the `BUILD` file remains readable). For example:
* `//third_party/upb:descriptor_upb_proto_stage0`
* `//third_party/upb:descriptor_upb_proto_stage1`
* `//third_party/upb:descriptor_upb_proto`
The stages are:
1. `stage0`: This uses the checked-in version of the generated code. The stage0 compiler is correct and outputs the same code as all other compilers, but it is unnecessarily slow because its protos were compiled in bootstrap mode. The stage0 compiler is used to generate protos for stage1.
2. `stage1`: The stage1 compiler is correct and fast, and therefore we use it in almost all cases (eg. `upb_proto_library()`). However its own protos were not generated using `upb_proto_library()`, so its `cc_library()` targets cannot be safely mixed with `upb_proto_library()`, as this would lead to duplicate symbols.
3. final (no stage): The final compiler is identical to the `stage1` compiler. The only difference is that its protos were built with `upb_proto_library()`. This doesn't matter very much for the compiler binary, but for the `cc_library()` targets like `//third_party/upb:reflection`, only the final targets can be safely linked in by other applications.
# "Bootstrap Mode" Protos
The checked-in generated code is generated in a special "bootstrap" mode that is a bit different than normal generated code. Bootstrap mode avoids depending on the internal representation of MiniTables or the messages, at the cost of slower runtime performance.
Bootstrap mode only interacts with MiniTables and messages using public APIs such as `upb_MiniTable_Build()`, `upb_Message_GetInt32()`, etc. This is very important as it allows us to change the internal representation without needing to regenerate our bootstrap protos. This will make it far easier to write CLs that change the internal representation, because it avoids the awkward dance of trying to regenerate the bootstrap protos when the compiler itself is broken due to bootstrap protos being out of date.
The bootstrap generated code does have two downsides:
1. The accessors are less efficient, because they look up MiniTable fields by number instead of hard-coding the MiniTableField into the generated code.
2. It requires runtime initialization of the MiniTables, which costs CPU cycles at startup, and also allocates memory which is never freed. Per google3 rules this is not really a leak, since this memory is still reachable via static variables, but it is undesirable in many contexts. We could fix this part by introducing the equivalent of `google::protobuf::ShutdownProtobufLibrary()`).
These downsides are fine for the bootstrapping process, but they are reason enough not to enable bootstrap mode in general for all protos.
# Bootstrapping Always Uses OSS Protos
To enable smooth syncing between Google3 and OSS, we always use an OSS version of the checked in generated code for `stage0`, even in google3.
This requires that the google3 code can be switched to reference the OSS proto names using a preprocessor define. We introduce the `UPB_DESC(xyz)` macro for this, which will expand into either `proto2_xyz` or `google_protobuf_xyz`. Any libraries used in `stage0` must use `UPB_DESC(xyz)` rather than refer to the symbol names directly.
PiperOrigin-RevId: 501458451
This is part of the ongoing effort to remove any hard-coding of layout offsets into the generated code (except via `upb_MiniTableField` values).
PiperOrigin-RevId: 497281306
This is part of the ongoing effort to remove any hard-coding of layout offsets into the generated code (except via `upb_MiniTableField` values).
PiperOrigin-RevId: 497266785
This is part of the ongoing effort to remove any hard-coding of layout offsets into the generated code (except via `upb_MiniTableField` values).
PiperOrigin-RevId: 497238313
Remove circular dependencies that were bouncing back and forth between
msg_internal.h and mini_table/, including:
- splitting out each mini table subtype into its own header
- moving the non-reflection message code into message/
- moving the accessors from mini_table/ to message/
PiperOrigin-RevId: 489121042
Example:
```
bazel-out/k8-fastbuild/bin/protos_generator/tests/test_model.upb.proto.cc: In member function 'void protos_generator::test::protos::internal::TestModelV1Access::set_value4(size_t, int32_t)':
bazel-out/k8-fastbuild/bin/protos_generator/tests/test_model.upb.proto.cc:559:14: error: comparison of unsigned expression in '>= 0' is always true [-Werror=type-limits]
559 | assert(0 <= index && index < len);
```
PiperOrigin-RevId: 489086133
Marcel Hlopko
Protobuf Team Bot
Adam Cozzette
Eric Salo
Hong Shin
xiaolou86
Joshua Haberman
Thomas Van Lenten
Mike Kruskal