Fil-C Bazel Template

This repository is a template for bootstrapping new Bazel projects using the Fil-C compiler. Fil-C is a memory-safe C/C++ compiler that provides spatial and temporal safety. You need Bazel 8.5.1 (use Bazelisk) You may need ruby, patchelf and other tools the filc compiler might need. The first compile might take a long time.

Getting Started

To create a new project using this template:

1. Create your repository:

   gh repo create my-filc-project --template hsaliak/filc-bazel-template --public # or --private for a private repo
   gh repo clone my-filc-project
   cd my-filc-project

   (Alternatively, clone this repository and remove the .git directory).

2. Verify the setup:

   bazel build //src:success
   bazel build //src:fail

   Running these with bazel run .. is a quick verification that the binaries work. Fail will trigger a Fil-C specific trap.

Creating New Targets

Since this template is pre-configured with the Fil-C toolchain, you can use standard Bazel C++ rules. Any cc_binary, cc_library, or cc_test target will automatically be built using filcc.

Example Binary

In a BUILD.bazel file:

cc_binary(
    name = "my_app",
    srcs = ["my_app.c"],
)

Example Library

cc_library(
    name = "my_lib",
    srcs = ["my_lib.c"],
    hdrs = ["my_lib.h"],
)

cc_binary(
    name = "my_app",
    srcs = ["my_app.c"],
    deps = [":my_lib"],
)

No special attributes are required. The .bazelrc in this repo ensures that --extra_toolchains=//toolchain:filc_toolchain is passed, making Fil-C the preferred toolchain.

Project Structure

• toolchain/: Contains the Bazel CC toolchain definition.
• src/: A sample C project to get you started.
• MODULE.bazel: Configures the Fil-C repository and registers the toolchain.
• .bazelrc: Sets default flags to use the Fil-C toolchain.

How it Works

The toolchain uses a wrapper script (toolchain/bin/filcc_wrapper.sh) that dynamically locates the filcc binary within the Bazel sandbox. It handles path mapping and ensure all necessary include paths are passed to the compiler using relative paths, satisfying Bazel's hermeticity requirements.

Verification

To verify that a binary has been compiled with Fil-C (and thus includes its safety checks), use the provided script:

./scripts/check_filc.sh bazel-bin/src/success

Examples

• src/fail.c: Demonstrates a use-after-free bug that Fil-C detects and stops.
• src/success.c: A standard safe C program.

To run the success case:

bazel run //src:success
./scripts/check_filc.sh bazel-bin/src/success

To run the failure case (will trigger a Fil-C panic):

bazel run //src:fail

Build Characteristics

Fil-C binaries are statically linked by default. This ensures that the custom runtime and safety checks are bundled with the executable. You can verify this using the file command:

file bazel-bin/src/success