docs/GetStarted/cmake_options_and_variables.md

# CMake Options and Variables

## Frequently-used CMake Variables

#### `CMAKE_BUILD_TYPE`:STRING

Sets the build type. Possible values are `Release`, `Debug`,
`RelWithDebInfo`/`FastBuild` and `MinSizeRel`. If unset, build type is set to
`Release`.

#### `CMAKE_<LANG>_COMPILER`:STRING

This is the command that will be used as the `<LANG>` compiler, which are `C`
and `CXX` in IREE. These variables are set to compile IREE with `clang` or
rather `clang++`. Once set, these variables can not be changed.

## IREE-specific CMake Options and Variables

This gives a brief explanation of IREE specific CMake options and variables.

#### `IREE_ENABLE_RUNTIME_TRACING`:BOOL

Enables instrumented runtime tracing. Defaults to `OFF`.

#### `IREE_ENABLE_MLIR`:BOOL

Enables MLIR/LLVM dependencies. Defaults to `ON`. MLIR/LLVM dependencies are
required when building the IREE compiler components. Therefore, the option is
automatically set to `ON` if `IREE_BUILD_COMPILER` is set to `ON`.

#### `IREE_ENABLE_EMITC`:BOOL

Enables the build of the out-of-tree MLIR dialect EmitC. Defaults to `OFF`. To
build the EmitC dialect, `IREE_ENABLE_MLIR` must be set to `ON`.

#### `IREE_BUILD_COMPILER`:BOOL

Builds the IREE compiler. Defaults to `ON`.

#### `IREE_BUILD_TESTS`:BOOL

Builds IREE unit tests. Defaults to `ON`.

#### `IREE_BUILD_DOCS`:BOOL

Builds IREE documentation. Defaults to `OFF`.

#### `IREE_BUILD_SAMPLES`:BOOL

Builds IREE sample projects. Defaults to `ON`.

#### `IREE_BUILD_DEBUGGER`:BOOL

Builds the IREE debugger app. Defaults to `OFF`.

#### `IREE_BUILD_PYTHON_BINDINGS`:BOOL

Builds the IREE python bindings. Defaults to `OFF`.

#### `IREE_BUILD_EXPERIMENTAL`:BOOL

Builds experimental projects. Defaults to `OFF`.

#### `IREE_HAL_DRIVERS_TO_BUILD`:STRING

*This does not have any effect at the moment, but will be supported in the
future!* Semicolon-separated list of HAL drivers to build, or `all` for building
all HAL drivers. Case-insensitive. Defaults to `all`. Example:
`-DIREE_HAL_DRIVERS_TO_BUILD="Vulkan;VMLA"`.

#### `IREE_TARGET_BACKENDS_TO_BUILD`:STRING

*This does not have any effect at the moment, but will be supported in the
future!* Semicolon-separated list of HAL drivers to build, or `all` for building
all HAL drivers. Case-insensitive. Defaults to `all`. Example:
`-DIREE_HAL_DRIVERS_TO_BUILD="Vulkan_SPIRV;VMLA"`.

#### `IREE_ENABLE_LLD`:BOOL

Use lld when linking. Defaults to `OFF`. This option is equivalent to
`-DIREE_USE_LINKER=lld`. The option `IREE_ENABLE_LLD` and `IREE_USE_LINKER` can
not be set at the same time.

#### `IREE_MLIR_DEP_MODE`:STRING

Defines the MLIR dependency mode. Case-sensitive. Can be `BUNDLED`, `DISABLED`
or `INSTALLED`. Defaults to `BUNDLED`. If set to `INSTALLED`, the variable
`MLIR_DIR` needs to be passed and that LLVM needs to be compiled with
`LLVM_ENABLE_RTTI` set to `ON`.

## MLIR-specific CMake Options and Variables

#### `MLIR_DIR`:STRING

Specifies the path where to look for the installed MLIR/LLVM packages. Required
if `IREE_MLIR_DEP_MODE` is set to `INSTALLED`.