Enable Clang plugin warnings in Bison source code

-Werror is generally suppressed in Bison-generated C/C++ code (as in all other
generated code) to silence warnings from the Bison skeleton code.  And the Clang
plugins suppress warnings in generated WORKDIR code based on the presumed source
location (i.e., taking #line directives into account).  So introduce a new
PLUGIN_WARNINGS_AS_ERRORS mode where warnings from Clang plugins are reported as
errors even if -Werror is suppressed.  That way, any warnings in the Bison
skeleton code still do not lead to compilation errors, while (at least plugin-
emitted) warnings in the genuine source code do.

Unfortunately this cannot also be enabled for Flex source code, as at least
Flex 2.5.39 generates poor code that does not properly prefix all skeleton code
with appropriate #line directives, so that some skeleton code would be mistaken
for genunie source code, and compilation would fail due to errors.

Also, %glr-parser Bison input appears to generate no #line directives at all (at
least with Bison 3.0.4), so all of connectivity/source/parse/sqlbison.y is
considered generated code and plugin warnings are still suppressed throughout.

Change-Id: Id746e81cbfa5f77628b0a34c7b82780948e7db08

5 files changed, 15 insertions, 6 deletions

diff --git a/compilerplugins/clang/pluginhandler.cxx b/compilerplugins/clang/pluginhandler.cxx
index 32651e18a5d0..bdee467fa82f 100644
--- a/compilerplugins/clang/pluginhandler.cxx
+++ b/compilerplugins/clang/pluginhandler.cxx
@@ -55,6 +55,7 @@ PluginHandler::PluginHandler( CompilerInstance& compiler, const vector< string >
     : compiler( compiler )
     , rewriter( compiler.getSourceManager(), compiler.getLangOpts())
     , scope( "mainfile" )
+    , warningsAsErrors( false )
     {
     set< string > rewriters;
     for( vector< string >::const_iterator it = args.begin();
@@ -101,6 +102,8 @@ void PluginHandler::handleOption( const string& option )
         {
         warningsOnly = option.substr(14);
         }
+    else if( option == "warnings-as-errors" )
+        warningsAsErrors = true;
     else
         report( DiagnosticsEngine::Fatal, "unknown option %0" ) << option;
     }
@@ -137,7 +140,7 @@ DiagnosticBuilder PluginHandler::report( DiagnosticsEngine::Level level, const c
     {
     DiagnosticsEngine& diag = compiler.getDiagnostics();
     // Do some mappings (e.g. for -Werror) that clang does not do for custom messages for some reason.
-    if( level == DiagnosticsEngine::Warning && diag.getWarningsAsErrors() && (plugin == nullptr || plugin != warningsOnly))
+    if( level == DiagnosticsEngine::Warning && ((diag.getWarningsAsErrors() && (plugin == nullptr || plugin != warningsOnly)) || warningsAsErrors))
         level = DiagnosticsEngine::Error;
     if( level == DiagnosticsEngine::Error && diag.getErrorsAsFatal())
         level = DiagnosticsEngine::Fatal;
diff --git a/compilerplugins/clang/pluginhandler.hxx b/compilerplugins/clang/pluginhandler.hxx
index 3992a70a2402..f0cece4deb8c 100644
--- a/compilerplugins/clang/pluginhandler.hxx
+++ b/compilerplugins/clang/pluginhandler.hxx
@@ -45,6 +45,7 @@ class PluginHandler
         set< SourceLocation > removals;
         string scope;
         string warningsOnly;
+        bool warningsAsErrors;
     };
 
 /**
diff --git a/solenv/gbuild/LinkTarget.mk b/solenv/gbuild/LinkTarget.mk
index 7f24a57f58ad..b00b3005091e 100644
--- a/solenv/gbuild/LinkTarget.mk
+++ b/solenv/gbuild/LinkTarget.mk
@@ -611,6 +611,7 @@ $(call gb_LinkTarget_get_target,$(1)) : EXTRAOBJECTLISTS :=
 $(call gb_LinkTarget_get_target,$(1)) : NATIVERES :=
 $(call gb_LinkTarget_get_target,$(1)) : VISIBILITY :=
 $(call gb_LinkTarget_get_target,$(1)) : WARNINGS_NOT_ERRORS :=
+$(call gb_LinkTarget_get_target,$(1)) : PLUGIN_WARNINGS_AS_ERRORS :=
 $(call gb_LinkTarget_get_target,$(1)) : EXTERNAL_CODE :=
 $(call gb_LinkTarget_get_target,$(1)) : SOVERSIONSCRIPT :=
 
@@ -1067,6 +1068,7 @@ endef
 define gb_LinkTarget_add_grammar
 $(call gb_YaccTarget_YaccTarget,$(2))
 $(call gb_LinkTarget_add_generated_exception_object,$(1),YaccTarget/$(2),$(3),$(if $(filter GCC,$(COM)),-Wno-unused-macros))
+$(call gb_GenCxxObject_get_target,YaccTarget/$(2)): PLUGIN_WARNINGS_AS_ERRORS := $(true)
 $(call gb_LinkTarget_get_clean_target,$(1)) : $(call gb_YaccTarget_get_clean_target,$(2))
 $(call gb_LinkTarget_get_headers_target,$(1)) : $(call gb_YaccTarget_get_header_target,$(2))
 $(call gb_LinkTarget__add_include,$(1),$(dir $(call gb_YaccTarget_get_header_target,$(2))))
diff --git a/solenv/gbuild/platform/com_GCC_class.mk b/solenv/gbuild/platform/com_GCC_class.mk
index 099c5d385fbe..8c32795f2db9 100644
--- a/solenv/gbuild/platform/com_GCC_class.mk
+++ b/solenv/gbuild/platform/com_GCC_class.mk
@@ -51,7 +51,7 @@ $(call gb_Helper_abbreviate_dirs,\
 		$(DEFS) \
 		$(gb_LTOFLAGS) \
 		$(if $(VISIBILITY),,$(gb_VISIBILITY_FLAGS)) \
-		$(if $(WARNINGS_NOT_ERRORS),,$(gb_CFLAGS_WERROR)) \
+		$(if $(WARNINGS_NOT_ERRORS),$(if $(ENABLE_WERROR),$(if $(PLUGIN_WARNINGS_AS_ERRORS),$(gb_COMPILER_PLUGINS_WARNINGS_AS_ERRORS))),$(gb_CFLAGS_WERROR)) \
 		$(if $(5),$(gb_COMPILER_PLUGINS)) \
 		$(2) \
 		$(if $(EXTERNAL_CODE),$(gb_CXXFLAGS_Wundef),$(gb_DEFS_INTERNAL)) \
@@ -75,7 +75,7 @@ $(call gb_Helper_abbreviate_dirs,\
 		$(DEFS) \
 		$(gb_LTOFLAGS) \
 		$(if $(VISIBILITY),,$(gb_VISIBILITY_FLAGS)) \
-		$(if $(WARNINGS_NOT_ERRORS),,$(gb_CFLAGS_WERROR)) \
+		$(if $(WARNINGS_NOT_ERRORS),$(if $(ENABLE_WERROR),$(if $(PLUGIN_WARNINGS_AS_ERRORS),$(gb_COMPILER_PLUGINS_WARNINGS_AS_ERRORS))),$(gb_CFLAGS_WERROR)) \
 		$(gb_COMPILER_PLUGINS) \
 		$(T_CFLAGS) $(T_CFLAGS_APPEND) \
 		$(if $(EXTERNAL_CODE),$(gb_CXXFLAGS_Wundef),$(gb_DEFS_INTERNAL)) \
@@ -92,7 +92,7 @@ $(call gb_Helper_abbreviate_dirs,\
 		$(DEFS) \
 		$(gb_LTOFLAGS) \
 		$(if $(VISIBILITY),,$(gb_VISIBILITY_FLAGS)) \
-		$(if $(WARNINGS_NOT_ERRORS),,$(gb_CFLAGS_WERROR)) \
+		$(if $(WARNINGS_NOT_ERRORS),$(if $(ENABLE_WERROR),$(if $(PLUGIN_WARNINGS_AS_ERRORS),$(gb_COMPILER_PLUGINS_WARNINGS_AS_ERRORS))),$(gb_CFLAGS_WERROR)) \
 		$(gb_COMPILER_PLUGINS) \
 		$(T_OBJCFLAGS) $(T_OBJCFLAGS_APPEND) \
 		$(if $(EXTERNAL_CODE),$(gb_CXXFLAGS_Wundef),$(gb_DEFS_INTERNAL)) \
@@ -112,7 +112,7 @@ $(call gb_Helper_abbreviate_dirs,\
 		$(DEFS) \
 		$(gb_LTOFLAGS) \
 		$(if $(VISIBILITY),,$(gb_VISIBILITY_FLAGS)) \
-		$(if $(WARNINGS_NOT_ERRORS),,$(gb_CFLAGS_WERROR)) \
+		$(if $(WARNINGS_NOT_ERRORS),$(if $(ENABLE_WERROR),$(if $(PLUGIN_WARNINGS_AS_ERRORS),$(gb_COMPILER_PLUGINS_WARNINGS_AS_ERRORS))),$(gb_CFLAGS_WERROR)) \
 		$(gb_COMPILER_PLUGINS) \
 		$(T_CXXFLAGS) $(T_CXXFLAGS_APPEND) \
 		$(if $(EXTERNAL_CODE),$(gb_CXXFLAGS_Wundef),$(gb_DEFS_INTERNAL)) \
@@ -129,7 +129,7 @@ $(call gb_Helper_abbreviate_dirs,\
 		$(DEFS) \
 		$(gb_LTOFLAGS) \
 		$(if $(VISIBILITY),,$(gb_VISIBILITY_FLAGS)) \
-		$(if $(WARNINGS_NOT_ERRORS),,$(gb_CFLAGS_WERROR)) \
+		$(if $(WARNINGS_NOT_ERRORS),$(if $(ENABLE_WERROR),$(if $(PLUGIN_WARNINGS_AS_ERRORS),$(gb_COMPILER_PLUGINS_WARNINGS_AS_ERRORS))),$(gb_CFLAGS_WERROR)) \
 		$(gb_COMPILER_PLUGINS) \
 		$(T_OBJCXXFLAGS) $(T_OBJCXXFLAGS_APPEND) \
 		$(if $(EXTERNAL_CODE),$(gb_CXXFLAGS_Wundef),$(gb_DEFS_INTERNAL)) \
diff --git a/solenv/gbuild/platform/com_GCC_defs.mk b/solenv/gbuild/platform/com_GCC_defs.mk
index f23705b3561a..7e30ed1a7af8 100644
--- a/solenv/gbuild/platform/com_GCC_defs.mk
+++ b/solenv/gbuild/platform/com_GCC_defs.mk
@@ -216,9 +216,12 @@ endif
 endif
 # extra EF variable to make the command line shorter (just like is done with $(SRCDIR) etc.)
 gb_COMPILER_PLUGINS_SETUP := EF=$(SRCDIR)/include/sal/log-areas.dox && ICECC_EXTRAFILES=$$EF CCACHE_EXTRAFILES=$$EF
+gb_COMPILER_PLUGINS_WARNINGS_AS_ERRORS := \
+    -Xclang -plugin-arg-loplugin -Xclang --warnings-as-errors
 else
 gb_COMPILER_PLUGINS :=
 gb_COMPILER_PLUGINS_SETUP :=
+gb_COMPILER_PLUGINS_WARNINGS_AS_ERRORS :=
 endif
 
 # Executable class