How Rebaze Works

Rebaze analyzes your existing build system and generates equivalent Bazel build files.

Migration Pipeline

┌─────────────┐     ┌─────────────┐     ┌─────────────┐     ┌─────────────┐
│   Analyze   │ ──▶ │    Parse    │ ──▶ │   Transform │ ──▶ │   Generate  │
│             │     │             │     │             │     │             │
│ Detect build│     │ Extract     │     │ Map deps,   │     │ Write Bazel │
│ system      │     │ targets     │     │ filter      │     │ files       │
└─────────────┘     └─────────────┘     └─────────────┘     └─────────────┘

Phase 1: Analysis

Rebaze detects the build system by looking for marker files:

File	Build System
CMakeLists.txt	CMake
build.gradle / build.gradle.kts	Gradle
pom.xml	Maven
Makefile	Make
Cargo.toml	Cargo

Phase 2: Parsing

CMake Parser

The CMake parser handles:

• Commands: project(), add_executable(), add_library(), etc.
• Variables: ${VAR}, $ENV{VAR}, $CACHE{VAR}
• Control flow: if(), foreach(), function(), macro()
• Generator expressions: $<TARGET_FILE:...>

Two parsing modes:

1. CMakeLists.txt parsing - Analyzes CMake files directly
2. cmake-file-api - Uses CMake’s File API for exact build info

Gradle Parser

Extracts:

• Project structure from settings.gradle
• Dependencies from build.gradle
• Plugins and versions
• Source sets

Phase 3: Transformation

1. Maps dependencies - Translates CMake/Gradle deps to Bazel targets
2. Filters artifacts - Removes platform-specific files and flags
3. Resolves includes - Converts include paths to Bazel format
4. Groups sources - Organizes files into appropriate targets

Dependency Mapping Example

CMake                          Bazel
─────                          ─────
find_package(ZLIB)      ──▶    @zlib
target_link_libraries(         deps = [
  mylib                          "@zlib",
  ZLIB::ZLIB                     "@openssl//:ssl",
  OpenSSL::SSL                 ]
)

Filtering

Rebaze filters out:

• Platform-specific sources (.rc, .plist)
• Build-type defines (_DEBUG, NDEBUG)
• Compiler-specific flags (/W4, -march=native)
• System include paths (/usr/include)

Phase 4: Generation

Always Generated

File	Purpose
MODULE.bazel	Module definition, dependencies
BUILD.bazel	Build targets
.bazelversion	Pins Bazel version
.bazelrc	Build configuration

For CMake with pkg-config

File	Purpose
third_party/BUILD.bazel	Dependency aliases
third_party/config.bzl	Strategy configuration

Build Generators

Generator	Description
native	Pure Rust implementation, always available
bazelle	Uses gazelle_cc for complex projects
auto	Prefers bazelle if available

Architecture

rebaze-cli         Command-line interface
    │
rebaze-core        Orchestration, shared logic
    │
    ├── rebaze-cmake          CMake parser
    ├── rebaze-cmake-file-api CMake File API
    ├── rebaze-gradle         Gradle parser
    │
rebaze-bazel       Bazel file generator
    │
rebaze-starlark    Starlark AST/serialization