[roll third_party/pigweed] pw_allocator: Make TrackingAllocator correct by construction

This CL removes the `Init` method from `TrackingAllocator` and
requires objects of that type to always be constructed with a valid
allocator. Previously, allowing the pointer to the wrapped allocator
to be null was believed to be needed to allow trackers around allocators
that might be optional depending on the platform. However, there is
already an allocator that can be used for this purpose: the
NullAllocator. As a result, the wrapped allocator can be a reference
instead of a pointer, and several conditional statement can be removed.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/193330

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: e8c65f4cc0c1568..40fa6880873d75c
Roller-URL: https://ci.chromium.org/b/8755288360234644545
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I2371b82175f9677c8df474e5338cddb09285364f
Reviewed-on: https://pigweed-review.googlesource.com/c/example/echo/+/193630
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
1 file changed
tree: 7f94c43ab5f6e26a36ed01603e4a662f628bf872
  1. src/
  2. targets/
  3. third_party/
  4. tools/
  5. .bazelrc
  6. .bazelversion
  7. .gitignore
  8. .gitmodules
  9. BUILD.bazel
  10. echo.bzl
  11. README.md
  12. requirements.in
  13. requirements_lock.txt
  14. WORKSPACE
README.md

Pigweed: minimal Bazel example

This repository contains a minimal example of a Bazel-based Pigweed project. It's an echo application for the STM32F429 Discovery Board.

Cloning

git clone --recursive https://pigweed.googlesource.com/example/echo

If you already cloned but forgot to include --recursive, run git submodule update --init to pull all submodules.

TODO: b/300695111 - Don't require submodules for this example.

Building

We‘ll assume you already have Bazel on your system. If you don’t, the recommended way to get it is through Bazelisk.

To build the entire project (including building the application for both the host and the STM32 Discovery Board), run

bazel build //...

To run the application locally on your machine, run,

bazel run //src:echo

Flashing

To flash the firmware to a STM32F429 Discovery Board connected to your machine, run,

bazel run //tools:flash

Note that you don't need to build the firmware first: Bazel knows that the firmware images are needed to flash the board, and will build them for you. And if you edit the source of the firmware or any of its dependencies, it will get rebuilt when you flash.

Communicating

Run,

bazel run //tools:miniterm -- /dev/ttyACM0 --filter=debug

to communicate with the board. When you transmit a character, you should get the same character back!