Ninja: include module mapper flags in `compile_commands.json`

Fixes: #24618

6 files changed, 66 insertions, 0 deletions

diff --git a/Tests/RunCMake/CXXModules/RunCMakeTest.cmake b/Tests/RunCMake/CXXModules/RunCMakeTest.cmake
index ada0c65..1009ce4 100644
--- a/Tests/RunCMake/CXXModules/RunCMakeTest.cmake
+++ b/Tests/RunCMake/CXXModules/RunCMakeTest.cmake
@@ -152,6 +152,11 @@ if ("named" IN_LIST CMake_TEST_MODULE_COMPILATION)
   run_cxx_module_test(scan_properties)
 endif ()
 
+# Tests which require compile commands support.
+if ("compile_commands" IN_LIST CMake_TEST_MODULE_COMPILATION)
+  run_cxx_module_test(export-compile-commands)
+endif ()
+
 # Tests which require collation work.
 if ("collation" IN_LIST CMake_TEST_MODULE_COMPILATION)
   run_cxx_module_test(public-req-private)
diff --git a/Tests/RunCMake/CXXModules/examples/export-compile-commands-check.cmake b/Tests/RunCMake/CXXModules/examples/export-compile-commands-check.cmake
new file mode 100644
index 0000000..5d7224b
--- /dev/null
+++ b/Tests/RunCMake/CXXModules/examples/export-compile-commands-check.cmake
@@ -0,0 +1,25 @@
+if (NOT EXISTS "${RunCMake_TEST_BINARY_DIR}/compile_commands.json")
+  list(APPEND RunCMake_TEST_FAILED
+    "No compile commands database detected.")
+endif ()
+
+file(READ "${RunCMake_TEST_BINARY_DIR}/compile_commands.json" compile_commands)
+
+string(JSON length
+  LENGTH "${compile_commands}")
+math(EXPR length "${length} - 1")
+foreach (item RANGE "${length}")
+  string(JSON entry
+    GET "${compile_commands}"
+    "${item}")
+  string(JSON command
+    GET "${entry}"
+    "command")
+  if (NOT command MATCHES "(@|-fmodule-mapper=).*\\.modmap")
+    string(JSON output
+      GET "${entry}"
+      "output")
+    list(APPEND RunCMake_TEST_FAILED
+      "Missing `.modmap` argument for '${output}'")
+  endif ()
+endforeach ()
diff --git a/Tests/RunCMake/CXXModules/examples/export-compile-commands-stderr.txt b/Tests/RunCMake/CXXModules/examples/export-compile-commands-stderr.txt
new file mode 100644
index 0000000..e868787
--- /dev/null
+++ b/Tests/RunCMake/CXXModules/examples/export-compile-commands-stderr.txt
@@ -0,0 +1,4 @@
+CMake Warning \(dev\) at CMakeLists.txt:9 \(target_sources\):
+  CMake's C\+\+ module support is experimental.  It is meant only for
+  experimentation and feedback to CMake developers.
+This warning is for project developers.  Use -Wno-dev to suppress it.
diff --git a/Tests/RunCMake/CXXModules/examples/export-compile-commands/CMakeLists.txt b/Tests/RunCMake/CXXModules/examples/export-compile-commands/CMakeLists.txt
new file mode 100644
index 0000000..2eb4d5f
--- /dev/null
+++ b/Tests/RunCMake/CXXModules/examples/export-compile-commands/CMakeLists.txt
@@ -0,0 +1,20 @@
+cmake_minimum_required(VERSION 3.24)
+project(cxx_modules_export_compile_commands CXX)
+
+include("${CMAKE_SOURCE_DIR}/../cxx-modules-rules.cmake")
+
+set(CMAKE_EXPORT_COMPILE_COMMANDS 1)
+
+add_executable(export-compile-commands)
+target_sources(export-compile-commands
+  PRIVATE
+    main.cxx
+  PRIVATE
+    FILE_SET CXX_MODULES
+      BASE_DIRS
+        "${CMAKE_CURRENT_SOURCE_DIR}"
+      FILES
+        importable.cxx)
+target_compile_features(export-compile-commands PUBLIC cxx_std_20)
+
+add_test(NAME export-compile-commands COMMAND export-compile-commands)
diff --git a/Tests/RunCMake/CXXModules/examples/export-compile-commands/importable.cxx b/Tests/RunCMake/CXXModules/examples/export-compile-commands/importable.cxx
new file mode 100644
index 0000000..607680a
--- /dev/null
+++ b/Tests/RunCMake/CXXModules/examples/export-compile-commands/importable.cxx
@@ -0,0 +1,6 @@
+export module importable;
+
+export int from_import()
+{
+  return 0;
+}
diff --git a/Tests/RunCMake/CXXModules/examples/export-compile-commands/main.cxx b/Tests/RunCMake/CXXModules/examples/export-compile-commands/main.cxx
new file mode 100644
index 0000000..feb38d2
--- /dev/null
+++ b/Tests/RunCMake/CXXModules/examples/export-compile-commands/main.cxx
@@ -0,0 +1,6 @@
+import importable;
+
+int main(int argc, char* argv[])
+{
+  return from_import();
+}