Issue 126890

Created attachment 85368 [details]
patch to fix DbgOut() infinite recursion warnings when compiling sal/inc/rtl/string.hxx with recent clang

When compiling OpenOffice with recent versions of clang, 7735 warnings that look like this:

In file included from /tmp/openoffice/aoo-4.2.0/main/sal/osl/unx/file_path_helper.cxx:36:
In file included from ./file_path_helper.hxx:32:
In file included from ../../inc/rtl/ustring.hxx:33:
../../inc/rtl/string.hxx:973:2: warning: all paths through this function will call itself [-Winfinite-recursion]
        { DbgOut( rMessage.getStr(), nOutType, pFileName, nLineNum); }
        ^
1 warning generated.

The problem is in this block of code in sal/inc/rtl/string.hxx:

inline void DbgOut( const rtl::OString& rMessage, sal_uInt16 nOutType, const sal_Char* pFileName, sal_uInt16 nLineNum )
	{ DbgOut( rMessage.getStr(), nOutType, pFileName, nLineNum); }

It appears to be trying to use function overloading to create a wrapper that calls a different flavor of DbgOut() that is declared in view tools/inc/tools/debug.hxx:

TOOLS_DLLPUBLIC void DbgOut( const sal_Char* pMsg, sal_uInt16 nOutType = DBG_OUT_TRACE,
             const sal_Char* pFile = NULL, sal_uInt16 nLine = 0 );

If the compiler has not yet encountered the latter before it compiles the code in string.hxx, then it decides is must convert the char * first argument in the inner cal back to rtl::OString& and call DbgOut() recursively.

In a normal build, this will always happen because the declaration in debug.hxx is conditional on the definition of the DBG_UTIL preprocessor symbol, which is undefined in normal builds.  Fix the problem in this case by protecting the the declaration in string.hxx with #ifdef DBG_UTIL. Fortunately there should not be any users of the string.hxx version of DbgOut() in this case.

The --enable-dbgutil configure option causes DBG_UTIL.  In this case the problem will be triggered if <tools/debug.hxx> is not included before <rtl/string.hxx> and there is no guarantee of that.  Fix the problem in this case by including <tools/debug.hxx> inside <rtl/string.hxx>.  This requires adding a couple of directories to the include path because not all users of <rtl/string.hxx> have done so, probably because they are not using any DBG_UTIL features.