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
Rust does not need (and should not need) these to be propagated up the tree. The Rust aspect just needs to use the thunks for a single proto_library() rule.
PiperOrigin-RevId: 564827273
A couple weeks ago we moved upb into the protobuf Git repo, and this change
continues the merger of the two repos by making them into a single Bazel repo.
This was mostly a matter of deleting upb's WORKSPACE file and fixing up a bunch
of references to reflect the new structure.
Most of the changes are pretty mechanical, but one thing that needed more
invasive changes was the Python script for generating CMakeLists.txt,
make_cmakelists.py. The WORKSPACE file it relied on no longer exists with this
change, so I updated it to hardcode the information it needed from that file.
PiperOrigin-RevId: 564810016
This is the first step of a migration to split apart upb_proto_library() into upb_c_proto_library() and upb_minitable_proto_library().
PiperOrigin-RevId: 563837216
I merged a handful of PRs on the upb repo after upb moved into the protobuf repo. This PR cherry-picks them here so that they will not be lost.
```
commit 7afb426a5a
Author: Keith Smiley <keithbsmiley@gmail.com>
Date: Thu Sep 7 11:36:01 2023 -0700
[bazel] Fix disallowing dylibs on darwin (#1180)
Since this bazel commit
ec5553352f
building dylibs like the ones in this rule on darwin platforms has been
unsupported. This feature is a default C++ toolchain feature to indicate
this. In bazel 7.x these dylibs will fail to link if they are still
built. As far as I can tell in the tests even if they are built they are
never used on macOS.
Co-authored-by: Adam Cozzette <acozzette@google.com>
commit 72decab5ec
Author: Keith Smiley <keithbsmiley@gmail.com>
Date: Thu Sep 7 09:42:20 2023 -0700
Add missing darwin_x86_64 CPU (#1181)
This CPU is often used when cross compiling from M1 machines. I'm also
hoping we can remove the legacy 'darwin' CPU.
commit ccadaf3196
Author: messense <messense@icloud.com>
Date: Fri Sep 8 00:28:54 2023 +0800
Fix `PyUpb_Message_MergeInternal` segfault (#1338)
when `PyUpb_Message_MergeFromString` returns `NULL`, currently
`PyUpb_Message_MergeInternal` will call `Py_DECREF` on `NULL`
which results in a segmentation fault.
This patch switches to `Py_XDECREF` to fix the segfault.
commit 2a5724d86e
Author: Kevin Greene <kgreenek@gmail.com>
Date: Wed Sep 6 16:46:35 2023 -0700
Fix lambda capture compiler error with c++20 (#1502)
When compiling with C++20, the following error is produced:
```
upb/mini_table.hpp:63:22: note: add explicit 'this' or '*this' capture
upb/mini_table.hpp: In lambda function:
upb/mini_table.hpp:71:22: error: implicit capture of 'this' via '[=]' is deprecated in C++20 [-Werror=deprecated]
71 | return appender_([=](char* buf) {
```
In C++20, it is no longer allowed to implicitly capture 'this' in a
lambda using [=].
This commit explicitly captures required values in the appropriate
lambdas and removes all uses of [=] with lambdas.
```
Closes#13908
COPYBARA_INTEGRATE_REVIEW=https://github.com/protocolbuffers/protobuf/pull/13908 from acozzette:upb 7afb426a5a
PiperOrigin-RevId: 563784513
This is the second attempt to fix our Git history. This should allow
"git blame" to work correctly in the upb/ directory even though our
automation unexpectedly blew away that directory.
This special `proto_library` behavior is known as an *alias library*:
https://bazel.build/reference/be/protocol-buffer#proto_library_args
Without this CL, the compilation of the added test fails with:
```
test_import_empty_srcs.upb.c:12:10: error:
module :test_import_empty_srcs_proto.upb does not depend on a
module exporting 'test.upb.h'
```
PiperOrigin-RevId: 545153380
"Thunks" are .c files with definitions for the inline functions in the gencode C
API. They are meant to be used from statically compiled languages that cannot
use inline C functions such as Rust.
Experimental, do not use. Our current plan is to delete this code in the order
of months. Without any prior warning.
PiperOrigin-RevId: 516522823
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 simplifies the code generation by making output agnostic to whether fasttables will be used or not.
This grows the generated code in the common case, but when fasttables are not being used the preprocessor will strip away the unused tables.
PiperOrigin-RevId: 499340805
Bazel has deprecated the host configuration and replaced it with the
exec configuration, which has proper support for transitions and remote
build execution.
Before there was a single code generator that generated both
.upb and .upbdefs, even though they are generated by different
rules. This worked fine as long as the codegen steps were
sandboxed, but if not it led to build errors.
Fixes https://github.com/protocolbuffers/upb/issues/354.
Adam Cozzette
Joshua Haberman
Protobuf Team Bot
Nevena Kotlaja
Thomas Van Lenten
Marcel Hlopko
Ivo List
Mike Kruskal
Protobuf Team
Joshua Haberman
Fabian Meumertzheim
Esun Kim
Benjamin Peterson