New loplugin:external

...warning about (for now only) functions and variables with external linkage
that likely don't need it.

The problems with moving entities into unnamed namespacs and breaking ADL
(as alluded to in comments in compilerplugins/clang/external.cxx) are
illustrated by the fact that while

  struct S1 { int f() { return 0; } };
  int f(S1 s) { return s.f(); }
  namespace N {
    struct S2: S1 { int f() { return 1; } };
    int f(S2 s) { return s.f(); }
  }
  int main() { return f(N::S2()); }

returns 1, both moving just the struct S2 into an nunnamed namespace,

  struct S1 { int f() { return 0; } };
  int f(S1 s) { return s.f(); }
  namespace N {
    namespace { struct S2: S1 { int f() { return 1; } }; }
    int f(S2 s) { return s.f(); }
  }
  int main() { return f(N::S2()); }

as well as moving just the function f overload into an unnamed namespace,

  struct S1 { int f() { return 0; } };
  int f(S1 s) { return s.f(); }
  namespace N {
    struct S2: S1 { int f() { return 1; } };
    namespace { int f(S2 s) { return s.f(); } }
  }
  int main() { return f(N::S2()); }

would each change the program to return 0 instead.

Change-Id: I4d09f7ac5e8f9bcd6e6bde4712608444b642265c
Reviewed-on: https://gerrit.libreoffice.org/60539
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

2 files changed, 8 insertions, 4 deletions

diff --git a/helpcompiler/source/HelpCompiler.cxx b/helpcompiler/source/HelpCompiler.cxx
index 4392328a08a5..d7ce8cfcc5d9 100644
--- a/helpcompiler/source/HelpCompiler.cxx
+++ b/helpcompiler/source/HelpCompiler.cxx
@@ -287,7 +287,7 @@ std::string myparser::dump(xmlNodePtr node)
     return app;
 }
 
-void trim(std::string& str)
+static void trim(std::string& str)
 {
     std::string::size_type pos = str.find_last_not_of(' ');
     if(pos != std::string::npos)
diff --git a/helpcompiler/source/HelpLinker.cxx b/helpcompiler/source/HelpLinker.cxx
index c6a9d5741f52..95bf39d764d1 100644
--- a/helpcompiler/source/HelpLinker.cxx
+++ b/helpcompiler/source/HelpLinker.cxx
@@ -75,7 +75,7 @@ IndexerPreProcessor::~IndexerPreProcessor()
         xsltFreeStylesheet( m_xsltStylesheetPtrContent );
 }
 
-std::string getEncodedPath( const std::string& Path )
+static std::string getEncodedPath( const std::string& Path )
 {
     OString aOStr_Path( Path.c_str() );
     OUString aOUStr_Path( OStringToOUString
@@ -146,7 +146,7 @@ struct Data
     }
 };
 
-void writeKeyValue_DBHelp( FILE* pFile, const std::string& aKeyStr, const std::string& aValueStr )
+static void writeKeyValue_DBHelp( FILE* pFile, const std::string& aKeyStr, const std::string& aValueStr )
 {
     if( pFile == nullptr )
         return;
@@ -813,7 +813,9 @@ void HelpLinker::main( std::vector<std::string> &args,
 // Variable to set an exception in "C" StructuredXMLErrorFunction
 static const HelpProcessingException* GpXMLParsingException = nullptr;
 
-extern "C" void StructuredXMLErrorFunction(SAL_UNUSED_PARAMETER void *, xmlErrorPtr error)
+extern "C" {
+
+static void StructuredXMLErrorFunction(SAL_UNUSED_PARAMETER void *, xmlErrorPtr error)
 {
     std::string aErrorMsg = error->message;
     std::string aXMLParsingFile;
@@ -827,6 +829,8 @@ extern "C" void StructuredXMLErrorFunction(SAL_UNUSED_PARAMETER void *, xmlError
     xmlSetStructuredErrorFunc( nullptr, nullptr );
 }
 
+}
+
 HelpProcessingErrorInfo& HelpProcessingErrorInfo::operator=( const struct HelpProcessingException& e )
 {
     m_eErrorClass = e.m_eErrorClass;