[lldb] Build the API unittests with -Wdocumentation (#128893)

The LLDB SB API headers should be -Wdocumentation clean as they might
get included by projects building with -Wdocumentation. Although I'd
love for all of LLDB to be clean, we're pretty far removed from that
goal. Until that changes, this PR will detect issues in the SB API
headers by including all the headers in the unittests (by including
LLDB/API.h) and building that with the warning, if the compiler supports
it.

rdar://143597614

Author: JDevlieghere

lldb/include/lldb/API/SBSaveCoreOptions.h

@@ -54,7 +54,7 @@ class LLDB_API SBSaveCoreOptions {
   /// Set the output file path
   ///
   /// \param
-  ///   output_file a \class SBFileSpec object that describes the output file.
+  ///   output_file a \ref SBFileSpec object that describes the output file.
   void SetOutputFile(SBFileSpec output_file);
 
   /// Get the output file spec

lldb/unittests/API/CMakeLists.txt

@@ -5,6 +5,16 @@ add_lldb_unittest(APITests
     liblldb
   )
 
+# Build with -Wdocumentation. This relies on the tests including all the API
+# headers through API/LLDB.h.
+check_cxx_compiler_flag("-Wdocumentation"
+                        CXX_SUPPORTS_DOCUMENTATION)
+if (CXX_SUPPORTS_DOCUMENTATION)
+  target_compile_options(APITests
+    PRIVATE -Wdocumentation)
+endif()
+
+
 if(Python3_RPATH)
   set_property(TARGET APITests APPEND PROPERTY BUILD_RPATH "${Python3_RPATH}")
 endif()

lldb/unittests/API/SBCommandInterpreterTest.cpp

@@ -8,9 +8,8 @@
 
 #include "gtest/gtest.h"
 
-#include "lldb/API/SBCommandInterpreter.h"
-#include "lldb/API/SBCommandReturnObject.h"
-#include "lldb/API/SBDebugger.h"
+// Use the umbrella header for -Wdocumentation.
+#include "lldb/API/LLDB.h"
 
 #include <cstring>
 #include <string>