Update docs to use top-level CMake targets

ghstack-source-id: 9877dbf
ghstack-comment-id: 3111967018
Pull-Request: #12807

Author: GregoryComer

docs/source/using-executorch-building-from-source.md

@@ -252,6 +252,17 @@ I 00:00:00.000764 executorch:executor_runner.cpp:180] Model executed successfull
 I 00:00:00.000770 executorch:executor_runner.cpp:184] 1 outputs:
 Output 0: tensor(sizes=[1], [2.])
 ```
+
+### CMake Targets
+
+To link against the ExecuTorch framework from CMake, the following top-level targets are exposed:
+
+ * `executorch_backends`: Contains all configured backends.
+ * `executorch_extensions`: Contains all configured extensions.
+ * `executorch_kernels`: Contains all configured kernel libraries.
+
+The backends, extensions, and kernels included in these targets are controlled by the various `EXECUTORCH_` CMake options specified by the build.
+
 ## Build ExecuTorch for Windows
 
 This document outlines the current known working build instructions for building and validating ExecuTorch on a Windows machine.

docs/source/using-executorch-cpp.md

@@ -40,7 +40,7 @@ Running a model using the low-level runtime APIs allows for a high-degree of con
 
 ## Building with CMake
 
-ExecuTorch uses CMake as the primary build system. Inclusion of the module and tensor APIs are controlled by the `EXECUTORCH_BUILD_EXTENSION_MODULE` and `EXECUTORCH_BUILD_EXTENSION_TENSOR` CMake options. As these APIs may not be supported on embedded systems, they are disabled by default when building from source. The low-level API surface is always included. To link, add the `executorch` target as a CMake dependency, along with `extension_module_static` and `extension_tensor`, if desired.
+ExecuTorch uses CMake as the primary build system. Inclusion of the module and tensor APIs are controlled by the `EXECUTORCH_BUILD_EXTENSION_MODULE` and `EXECUTORCH_BUILD_EXTENSION_TENSOR` CMake options. As these APIs may not be supported on embedded systems, they are disabled by default when building from source. The low-level API surface is always included. To link, add the `executorch` target as a CMake dependency, along with `executorch_backends`, `executorch_extensions`, and `extension_kernels`, to link all configured backends, extensions, and kernels.
 
 ```
 # CMakeLists.txt
@@ -49,10 +49,9 @@ add_subdirectory("executorch")
 target_link_libraries(
     my_target
     PRIVATE executorch
-    extension_module_static
-    extension_tensor
-    optimized_native_cpu_ops_lib
-    xnnpack_backend)
+    executorch_backends
+    executorch_extensions
+    executorch_kernels)
 ```
 
 See [Building from Source](using-executorch-building-from-source.md) for more information on the CMake build process.