From 628fefa7a797636c1dce9ba058549f2191507e1c Mon Sep 17 00:00:00 2001
From: Joshua Goldstein <goldstei@google.com>
Date: Mon, 6 Jan 2025 14:38:56 -0800
Subject: [PATCH] pw_toolchain: Clang can specify path to gcc toolchain
MIME-Version: 1.0
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- Add new functions in clang_flags.cmake with named arguments instead of
  positional ones
- Add ability to specify path of gcc toolchain to be used

Change-Id: I0aa585be6ba7b2f45fa52d985dc87d90fc36b15f
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/257312
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
Commit-Queue: Joshua Goldstein <goldstei@google.com>
Reviewed-by: Ewout van Bekkum <ewout@google.com>
Pigweed-Auto-Submit: Joshua Goldstein <goldstei@google.com>
Docs-Not-Needed: Joshua Goldstein <goldstei@google.com>
Reviewed-by: Wyatt Hepler <hepler@google.com>
Presubmit-Verified: CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com>
---
 pw_toolchain/arm_clang/clang_flags.cmake | 99 ++++++++++++++++++++++++
 1 file changed, 99 insertions(+)

diff --git a/pw_toolchain/arm_clang/clang_flags.cmake b/pw_toolchain/arm_clang/clang_flags.cmake
index a66045ccc6..9c7c81c69d 100644
--- a/pw_toolchain/arm_clang/clang_flags.cmake
+++ b/pw_toolchain/arm_clang/clang_flags.cmake
@@ -11,6 +11,9 @@
 # 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")
 
 # Clang isn't a plug-and-play experience for Cortex-M baremetal targets; it's
 # missing C runtime libraries, C/C++ standard libraries, and a few other
@@ -33,7 +36,38 @@ function(_pw_get_clang_flags OUTPUT_VARIABLE TYPE)
   set(${OUTPUT_VARIABLE} ${_result} PARENT_SCOPE)
 endfunction()
 
+# This function is meant to replace _pw_get_clang_flags and now uses named
+# variables.
+function(_pw_get_clang_runtime_env_flags OUTPUT_VARIABLE TYPE)
+  pw_parse_arguments(
+    NUM_POSITIONAL_ARGS
+      2
+    ONE_VALUE_ARGS
+      GCC_TOOLCHAIN_PATH
+    MULTI_VALUE_ARGS
+      ARCH_FLAGS
+  )
+
+  set(GCC_PATH_ARG "")
+  if (NOT "${arg_GCC_TOOLCHAIN_PATH}" STREQUAL "")
+    set(GCC_PATH_ARG "--gcc-exe-path;${arg_GCC_TOOLCHAIN_PATH}")
+  endif()
+
+  execute_process(
+    COMMAND python
+            $ENV{PW_ROOT}/pw_toolchain/py/pw_toolchain/clang_arm_toolchain.py
+            ${GCC_PATH_ARG}
+            ${TYPE} -- ${arg_ARCH_FLAGS}
+    WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
+    OUTPUT_VARIABLE _result
+    OUTPUT_STRIP_TRAILING_WHITESPACE
+  )
+  set(${OUTPUT_VARIABLE} ${_result} PARENT_SCOPE)
+endfunction()
+
+
 # This returns the compile flags needed for compiling with clang as a string.
+# This function is deprecated. Use pw_get_clang_runtime_env_compile_flags.
 #
 # Usage:
 #
@@ -45,11 +79,44 @@ endfunction()
 #   pw_get_clang_compile_flags(result -mcpu=cortex-m33 -mthumb -mfloat-abi=hard)
 #
 function(pw_get_clang_compile_flags OUTPUT_VARIABLE)
+  message(DEPRECATION "Use pw_get_clang_runtime_env_compile_flags")
   _pw_get_clang_flags(_result --cflags ${ARGN})
   set(${OUTPUT_VARIABLE} ${_result} PARENT_SCOPE)
 endfunction()
 
+# This returns the compile flags needed for compiling with clang as a string.
+#
+# Usage:
+#
+#   pw_get_clang_runtime_env_compile_flags(OUTPUT_VARIABLE
+#                                         [GCC_TOOLCHAIN_PATH <path>]
+#                                         [ARCH_FLAGS <flags>...])
+#
+# Example:
+#
+#   # Retrieve the compile flags needed for this arch and store them in "result".
+#   pw_get_clang_runtime_env_compile_flags(result ARCH_FLAGS -mcpu=cortex-m33 -mthumb -mfloat-abi=hard)
+#
+function(pw_get_clang_runtime_env_compile_flags OUTPUT_VARIABLE)
+  pw_parse_arguments(
+    NUM_POSITIONAL_ARGS
+      1
+    ONE_VALUE_ARGS
+      GCC_TOOLCHAIN_PATH
+    MULTI_VALUE_ARGS
+      ARCH_FLAGS
+  )
+
+  _pw_get_clang_runtime_env_flags(_result --cflags
+    GCC_TOOLCHAIN_PATH
+      ${arg_GCC_TOOLCHAIN_PATH}
+    ARCH_FLAGS
+      ${arg_ARCH_FLAGS})
+  set(${OUTPUT_VARIABLE} ${_result} PARENT_SCOPE)
+endfunction()
+
 # This returns the link flags needed for compiling with clang as a string.
+# This function is deprecated. Use pw_get_clang_runtime_env_link_flags.
 #
 # Usage:
 #
@@ -61,6 +128,38 @@ endfunction()
 #   pw_get_clang_link_flags(result -mcpu=cortex-m33 -mthumb -mfloat-abi=hard)
 #
 function(pw_get_clang_link_flags OUTPUT_VARIABLE)
+  message(DEPRECATION "Use pw_get_clang_runtime_env_link_flags")
   _pw_get_clang_flags(_result --ldflags ${ARGN})
   set(${OUTPUT_VARIABLE} ${_result} PARENT_SCOPE)
 endfunction()
+
+# This returns the compile flags needed for compiling with clang as a string.
+#
+# Usage:
+#
+#   pw_get_clang_runtime_env_link_flags(OUTPUT_VARIABLE
+#                                       [GCC_TOOLCHAIN_PATH <path>]
+#                                       [ARCH_FLAGS <flags>...])
+#
+# Example:
+#
+#   # Retrieve the compile flags needed for this arch and store them in "result".
+#   pw_get_clang_runtime_env_link_flags(result ARCH_FLAGS -mcpu=cortex-m33 -mthumb -mfloat-abi=hard)
+#
+function(pw_get_clang_runtime_env_link_flags OUTPUT_VARIABLE)
+  pw_parse_arguments(
+    NUM_POSITIONAL_ARGS
+      1
+    ONE_VALUE_ARGS
+      GCC_TOOLCHAIN_PATH
+    MULTI_VALUE_ARGS
+      ARCH_FLAGS
+  )
+
+  _pw_get_clang_runtime_env_flags(_result --ldflags
+    GCC_TOOLCHAIN_PATH
+      ${arg_GCC_TOOLCHAIN_PATH}
+    ARCH_FLAGS
+      ${arg_ARCH_FLAGS})
+  set(${OUTPUT_VARIABLE} ${_result} PARENT_SCOPE)
+endfunction()