cmake: Migrate all facades to use BACKEND variables

Migrates all CMake facades to use BACKEND variables which are
defined in backend.cmake variables, similar to GN.

Change-Id: I63dd1a81aa0a796366f6c78c4823e6081a6463f1
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/117413
Reviewed-by: Wyatt Hepler <[email protected]>
Commit-Queue: Auto-Submit <[email protected]>
Pigweed-Auto-Submit: Ewout van Bekkum <[email protected]>

pw_assert/CMakeLists.txt

@@ -13,6 +13,7 @@
 # the License.
 
 include($ENV{PW_ROOT}/pw_build/pigweed.cmake)
+include($ENV{PW_ROOT}/pw_assert/backend.cmake)
 
 pw_add_module_config(pw_assert_CONFIG)
 
@@ -49,6 +50,8 @@ if(DEFINED pw_assert_BACKEND)
 endif()
 
 pw_add_module_facade(pw_assert.assert
+  BACKEND
+    pw_assert.assert_BACKEND
   HEADERS
     public/pw_assert/assert.h
   PUBLIC_INCLUDES
@@ -58,6 +61,8 @@ pw_add_module_facade(pw_assert.assert
 )
 
 pw_add_module_facade(pw_assert.check
+  BACKEND
+    pw_assert.check_BACKEND
   HEADERS
     public/pw_assert/check.h
     public/pw_assert/internal/check_impl.h

pw_assert/backend.cmake

@@ -0,0 +1,22 @@
+# Copyright 2022 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+include_guard(GLOBAL)
+
+include($ENV{PW_ROOT}/pw_build/pigweed.cmake)
+
+# Backend for the pw_assert module's CHECK facade.
+pw_add_backend_variable(pw_assert.assert_BACKEND)
+
+# Backend for the pw_assert module's ASSERT facade.
+pw_add_backend_variable(pw_assert.check_BACKEND)

pw_assert_basic/CMakeLists.txt

@@ -13,8 +13,11 @@
 # the License.
 
 include($ENV{PW_ROOT}/pw_build/pigweed.cmake)
+include($ENV{PW_ROOT}/pw_assert_basic/backend.cmake)
 
 pw_add_module_facade(pw_assert_basic.handler
+  BACKEND
+    pw_assert_basic.handler_BACKEND
   HEADERS
     public/pw_assert_basic/handler.h
   PUBLIC_INCLUDES

pw_assert_basic/backend.cmake

@@ -0,0 +1,29 @@
+# Copyright 2022 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+include_guard(GLOBAL)
+
+include($ENV{PW_ROOT}/pw_build/pigweed.cmake)
+
+# Handler backend for the pw_assert_basic module which implements
+# pw_assert_basic_HandleFailure, this defaults to the basic_handler.
+#
+# Note: Don't confuse pw_assert.check_BACKEND and
+# pw_assert_basic.handler_BACKEND:
+# 1) pw_assert.check_BACKEND must be set to pw_assert_basic.check_backend in
+#    order to use this module which ensures that asserts always invoke
+#    pw_assert_basic_HandleFailure.
+# 2) pw_assert_basic.handler_BACKEND allows you to switch out the
+#    implementation of the handler which is invoked (i.e.
+#    pw_assert_basic_HandleFailure).
+pw_add_backend_variable(pw_assert_basic.handler_BACKEND)

pw_chrono/CMakeLists.txt

@@ -13,6 +13,7 @@
 # the License.
 
 include($ENV{PW_ROOT}/pw_build/pigweed.cmake)
+include($ENV{PW_ROOT}/pw_chrono/backend.cmake)
 include($ENV{PW_ROOT}/pw_protobuf_compiler/proto.cmake)
 
 pw_add_module_library(pw_chrono.epoch
@@ -23,6 +24,8 @@ pw_add_module_library(pw_chrono.epoch
 )
 
 pw_add_module_facade(pw_chrono.system_clock
+  BACKEND
+    pw_chrono.system_clock_BACKEND
   HEADERS
     public/pw_chrono/internal/system_clock_macros.h
     public/pw_chrono/system_clock.h
@@ -36,6 +39,8 @@ pw_add_module_facade(pw_chrono.system_clock
 )
 
 pw_add_module_facade(pw_chrono.system_timer
+  BACKEND
+    pw_chrono.system_timer_BACKEND
   HEADERS
     public/pw_chrono/system_timer.h
   PUBLIC_INCLUDES

pw_chrono/backend.cmake

@@ -0,0 +1,22 @@
+# Copyright 2022 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+include_guard(GLOBAL)
+
+include($ENV{PW_ROOT}/pw_build/pigweed.cmake)
+
+# Backend for the pw_chrono module's system_clock.
+pw_add_backend_variable(pw_chrono.system_clock_BACKEND)
+
+# Backend for the pw_chrono module's system_timer.
+pw_add_backend_variable(pw_chrono.system_timer_BACKEND)

pw_cpu_exception/CMakeLists.txt

@@ -13,8 +13,11 @@
 # the License.
 
 include($ENV{PW_ROOT}/pw_build/pigweed.cmake)
+include($ENV{PW_ROOT}/pw_cpu_exception/backend.cmake)
 
 pw_add_module_facade(pw_cpu_exception.entry
+  BACKEND
+    pw_cpu_exception.entry_BACKEND
   HEADERS
     public/pw_cpu_exception/entry.h
     public/pw_cpu_exception/state.h
@@ -25,6 +28,8 @@ pw_add_module_facade(pw_cpu_exception.entry
 )
 
 pw_add_module_facade(pw_cpu_exception.handler
+  BACKEND
+    pw_cpu_exception.handler_BACKEND
   HEADERS
     public/pw_cpu_exception/handler.h
   PUBLIC_INCLUDES
@@ -37,6 +42,8 @@ pw_add_module_facade(pw_cpu_exception.handler
 )
 
 pw_add_module_facade(pw_cpu_exception.support
+  BACKEND
+    pw_cpu_exception.support_BACKEND
   HEADERS
     public/pw_cpu_exception/support.h
   PUBLIC_INCLUDES

pw_cpu_exception/backend.cmake

@@ -0,0 +1,21 @@
+# Copyright 2022 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+include_guard(GLOBAL)
+
+include($ENV{PW_ROOT}/pw_build/pigweed.cmake)
+
+# Backends for the pw_cpu_exception module.
+pw_add_backend_variable(pw_cpu_exception.entry_BACKEND)
+pw_add_backend_variable(pw_cpu_exception.handler_BACKEND)
+pw_add_backend_variable(pw_cpu_exception.support_BACKEND)

pw_cpu_exception/backend.gni

@@ -13,7 +13,7 @@
 # the License.
 
 declare_args() {
-  # Backend for the pw_cpu_exception module.
+  # Backends for the pw_cpu_exception module.
   pw_cpu_exception_ENTRY_BACKEND = ""
   pw_cpu_exception_HANDLER_BACKEND = ""
   pw_cpu_exception_SUPPORT_BACKEND = ""

pw_interrupt/CMakeLists.txt

@@ -13,8 +13,11 @@
 # the License.
 
 include($ENV{PW_ROOT}/pw_build/pigweed.cmake)
+include($ENV{PW_ROOT}/pw_interrupt/backend.cmake)
 
 pw_add_module_facade(pw_interrupt.context
+  BACKEND
+    pw_interrupt.context_BACKEND
   HEADERS
     public/pw_interrupt/context.h
   PUBLIC_INCLUDES

pw_interrupt/backend.cmake

@@ -0,0 +1,19 @@
+# Copyright 2022 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+include_guard(GLOBAL)
+
+include($ENV{PW_ROOT}/pw_build/pigweed.cmake)
+
+# Backends for the pw_interrupt module.
+pw_add_backend_variable(pw_interrupt.context_BACKEND)

pw_interrupt/backend.gni

@@ -13,6 +13,6 @@
 # the License.
 
 declare_args() {
-  # Backend for the pw_interrupt module.
+  # Backends for the pw_interrupt module.
   pw_interrupt_CONTEXT_BACKEND = ""
 }

pw_log/CMakeLists.txt

@@ -13,6 +13,7 @@
 # the License.
 
 include($ENV{PW_ROOT}/pw_build/pigweed.cmake)
+include($ENV{PW_ROOT}/pw_log/backend.cmake)
 include($ENV{PW_ROOT}/pw_protobuf_compiler/proto.cmake)
 
 pw_add_module_config(pw_log_CONFIG)
@@ -29,6 +30,8 @@ pw_add_module_library(pw_log.config
 )
 
 pw_add_module_facade(pw_log
+  BACKEND
+    pw_log_BACKEND
   HEADERS
     public/pw_log/levels.h
     public/pw_log/log.h

pw_log/backend.cmake

@@ -0,0 +1,19 @@
+# Copyright 2022 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+include_guard(GLOBAL)
+
+include($ENV{PW_ROOT}/pw_build/pigweed.cmake)
+
+# Backend for the pw_log module.
+pw_add_backend_variable(pw_log_BACKEND)

pw_log_string/CMakeLists.txt

@@ -13,6 +13,7 @@
 # the License.
 
 include($ENV{PW_ROOT}/pw_build/pigweed.cmake)
+include($ENV{PW_ROOT}/pw_log_string/backend.cmake)
 
 pw_add_module_library(pw_log_string
   IMPLEMENTS_FACADES
@@ -29,6 +30,8 @@ pw_add_module_library(pw_log_string
 )
 
 pw_add_module_facade(pw_log_string.handler
+  BACKEND
+    pw_log_string.handler_BACKEND
   HEADERS
     public/pw_log_string/handler.h
   PUBLIC_INCLUDES

pw_log_string/backend.cmake

@@ -0,0 +1,20 @@
+# Copyright 2022 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+include_guard(GLOBAL)
+
+include($ENV{PW_ROOT}/pw_build/pigweed.cmake)
+
+# The pw_log_string.handler backend implements the pw_Log C API which is also
+# used by the pw_log_string module's implementation of the pw_log facade.
+pw_add_backend_variable(pw_log_string.handler_BACKEND)

pw_perf_test/CMakeLists.txt

@@ -13,6 +13,7 @@
 # the License.
 
 include($ENV{PW_ROOT}/pw_build/pigweed.cmake)
+include($ENV{PW_ROOT}/pw_perf_test/backend.cmake)
 include($ENV{PW_ROOT}/pw_protobuf_compiler/proto.cmake)
 
 pw_add_module_library(pw_perf_test.duration_unit
@@ -23,6 +24,8 @@ pw_add_module_library(pw_perf_test.duration_unit
 )
 
 pw_add_module_facade(pw_perf_test.timer
+  BACKEND
+    pw_perf_test.timer_BACKEND
   HEADERS
     public/pw_perf_test/internal/timer.h
   PUBLIC_INCLUDES

pw_perf_test/backend.cmake

@@ -0,0 +1,18 @@
+# Copyright 2022 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+include_guard(GLOBAL)
+
+include($ENV{PW_ROOT}/pw_build/pigweed.cmake)
+
+pw_add_backend_variable(pw_perf_test.timer_BACKEND)

pw_rpc/system_server/CMakeLists.txt

@@ -13,8 +13,11 @@
 # the License.
 
 include("$ENV{PW_ROOT}/pw_build/pigweed.cmake")
+include($ENV{PW_ROOT}/pw_rpc/system_server/backend.cmake)
 
 pw_add_module_facade(pw_rpc.system_server
+  BACKEND
+    pw_rpc.system_server_BACKEND
   PUBLIC_DEPS
     pw_rpc.server
     pw_stream

pw_rpc/system_server/backend.cmake

@@ -0,0 +1,19 @@
+# Copyright 2022 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+include_guard(GLOBAL)
+
+include($ENV{PW_ROOT}/pw_build/pigweed.cmake)
+
+# Backend for the pw_rpc_system_server module.
+pw_add_backend_variable(pw_rpc.system_server_BACKEND)