fbc: #pragma push( lookup108 ) for fbc-1.08.x unqualified symbol look ups

- this #pragma allows using an older method of symbol lookups
- no guarantee that all lookups are identical to 1.08.x and earlier as they are several bugs fixed relating to symbol lookups and there may be related changes
- this should allow users to compile older code a little easier
- symbol lookup (with respect to namespaces and extended types) are continuing to be developed
- the intent is to remove this #pragma in a future version

Author: jayrm

changelog.txt

@@ -57,6 +57,7 @@ Version 1.09.0
 - sf.net #945, #948: improve error message for ambiguous symbol access to list all of the conflicted symbols
 - ./inc/fbc-int/array.bi - add fb.ArrayLen( array ) function to return total number of elements in an array
 - ./inc/fbc-int/array.bi - add fb.ArraySize( array ) function to return total size of an array in bytes
+- fbc: #pragma push( lookup108 ) to use symbol lookup method from fbc-1.08.x and earlier on unqualified symbol names
 
 [fixed]
 - github #315: set parameters when calling SCREENCONTROL (was broken in fbc 1.08.0 due to new LONG/LONGINT SCREENCONTROL API's)

src/compiler/fb.bas

@@ -557,6 +557,7 @@ sub fbGlobalInit()
 	env.clopt.gfx           = FALSE
 	env.clopt.pic           = FALSE
 	env.clopt.msbitfields   = FALSE
+	env.clopt.lookup108     = FALSE
 	env.clopt.stacksize     = 0 '' default will be set by fbSetOption() called from hParseArgs()
 	env.clopt.objinfo       = TRUE
 	env.clopt.showincludes  = FALSE
@@ -657,6 +658,8 @@ sub fbSetOption( byval opt as integer, byval value as integer )
 		env.clopt.export = value
 	case FB_COMPOPT_MSBITFIELDS
 		env.clopt.msbitfields = value
+	case FB_COMPOPT_LOOKUP108
+		env.clopt.lookup108 = value
 	case FB_COMPOPT_MULTITHREADED
 		env.clopt.multithreaded = value
 	case FB_COMPOPT_GFX
@@ -759,6 +762,8 @@ function fbGetOption( byval opt as integer ) as integer
 		function = env.clopt.export
 	case FB_COMPOPT_MSBITFIELDS
 		function = env.clopt.msbitfields
+	case FB_COMPOPT_LOOKUP108
+		function = env.clopt.lookup108
 	case FB_COMPOPT_MULTITHREADED
 		function = env.clopt.multithreaded
 	case FB_COMPOPT_GFX
@@ -784,7 +789,7 @@ end function
 '':::::
 sub fbChangeOption(byval opt as integer, byval value as integer)
 	select case as const opt
-	case FB_COMPOPT_MSBITFIELDS
+	case FB_COMPOPT_MSBITFIELDS, FB_COMPOPT_LOOKUP108
 		fbSetOption( opt, value )
 
 	case FB_COMPOPT_LANG

src/compiler/fb.bi

@@ -100,6 +100,7 @@ enum FB_COMPOPT
 	FB_COMPOPT_FBRT                 '' boolean: we are building or linking the fbrt library
 	FB_COMPOPT_EXPORT               '' boolean: export all symbols declared as EXPORT?
 	FB_COMPOPT_MSBITFIELDS          '' boolean: use M$'s bitfields packing?
+	FB_COMPOPT_LOOKUP108            '' boolean: use old lookup rules fbc 1.08.x and earlier
 	FB_COMPOPT_MULTITHREADED        '' boolean: -mt
 	FB_COMPOPT_GFX                  '' boolean: -gfx (whether gfxlib should be linked)
 	FB_COMPOPT_PIC                  '' boolean: -pic (whether to use position-independent code)
@@ -303,6 +304,7 @@ type FBCMMLINEOPT
 	fbrt            as integer              '' we are building or linking fbrt (default = false)
 	export          as integer              '' export all symbols declared as EXPORT (default = true)
 	msbitfields     as integer              '' use M$'s bitfields packing
+	lookup108       as integer              '' use old lookup rules fbc 1.08.x and earlier
 	multithreaded   as integer              '' link against thread-safe runtime library (default = false)
 	gfx             as integer              '' Link against gfx library (default = false)
 	pic             as integer              '' Whether to use position-independent code (default = false)

src/compiler/pp-pragma.bas

@@ -30,6 +30,7 @@ end type
 
 enum LEXPP_PRAGMAOPT_ENUM
 	LEXPP_PRAGMAOPT_BITFIELD
+	LEXPP_PRAGMAOPT_LOOKUP108
 	LEXPP_PRAGMAOPT_ONCE
 	LEXPP_PRAGMAOPT_WARNCONSTNESS
 	LEXPP_PRAGMAOPT_RESERVE
@@ -49,6 +50,7 @@ end type
 	dim shared pragmaOpt(0 to LEXPP_PRAGMAS-1) as LEXPP_PRAGMAOPT => _
 	{ _
 		("msbitfields", FB_COMPOPT_MSBITFIELDS, LEXPP_PRAGMAFLAG_DEFAULT         ), _
+		("lookup108"  , FB_COMPOPT_LOOKUP108  , LEXPP_PRAGMAFLAG_DEFAULT         ), _
 		("once"       , 0                     , LEXPP_PRAGMAFLAG_HAS_CALLBACK    ), _
 		("constness"  , FB_PDCHECK_CONSTNESS  , LEXPP_PRAGMAFLAG_PDCHECK or LEXPP_PRAGMAFLAG_DEFAULT ), _
 		("reserve"    , 0                     , LEXPP_PRAGMAFLAG_HAS_CALLBACK    ) _

src/compiler/symb.bas

@@ -869,6 +869,79 @@ function symbNewChainpool _
 
 end function
 
+'':::::
+function symbLookup108 _
+	( _
+		byval id as zstring ptr, _
+		byref tk as FB_TOKEN, _
+		byref tk_class as FB_TKCLASS _
+	) as FBSYMCHAIN ptr
+
+	static as zstring * FB_MAXNAMELEN+1 sname
+
+	'' assume it's an unknown identifier
+	tk = FB_TK_ID
+	tk_class = FB_TKCLASS_IDENTIFIER
+
+	hUcase( *id, sname )
+	id = @sname
+
+	dim as uinteger index = hashHash( id )
+	dim as FBSYMCHAIN ptr chain_ = NULL
+
+	'' for each nested hash tb, starting from last
+	dim as FBHASHTB ptr hashtb = symb.hashlist.tail
+
+	do
+		dim as FBSYMBOL ptr sym = hashLookupEx( @hashtb->tb, id, index )
+		if( sym <> NULL ) then
+			chain_ = chainpoolNext()
+
+			chain_->sym = sym
+			chain_->next = NULL
+			chain_->isimport = FALSE
+
+			if( sym->class = FB_SYMBCLASS_KEYWORD ) then
+				tk = sym->key.id
+				tk_class = sym->key.tkclass
+				'' return if it's a KEYWORD or a OPERATOR token, they
+				'' can't never be redefined, even inside namespaces
+				if( tk_class <> FB_TKCLASS_QUIRKWD ) then
+					return chain_
+				end if
+			end if
+
+			'' return if it's not the global ns (as in C++, any nested
+			'' symbol has precedence over any imported one, even if the
+			'' latter was imported in the current ns)
+			if( hashtb->owner <> @symbGetGlobalNamespc( ) ) then
+				return chain_
+			else
+				'' also if we are at the global ns, no need to check the imports
+				if( symbGetCurrentNamespc( ) = @symbGetGlobalNamespc( ) ) then
+					return chain_
+				end if
+
+				'' check (and add) the imports..
+				exit do
+			end if
+		end if
+
+		hashtb = hashtb->prev
+	loop while( hashtb <> NULL )
+
+	'' now try the imported namespaces..
+	dim as FBSYMCHAIN ptr imp_chain = hashLookupEx( @symb.imphashtb, id, index )
+	if( chain_ = NULL ) then
+		return imp_chain
+	end if
+
+	chain_->next = imp_chain
+
+	return chain_
+
+end function
+
 '':::::
 function symbLookup _
 	( _
@@ -918,6 +991,10 @@ function symbLookup _
 		hashtb = hashtb->prev
 	loop while( hashtb <> NULL )
 
+	'' use old lookup method from fbc 1.08.x and earlier?
+	if( env.clopt.lookup108 ) then
+		return symbLookup108( id, tk, tk_class )
+	end if
 	'' any symbol not in the global namespace or we are already in the global namespace?
 	'' check the whole list before we check the imports
 	hashtb = symb.hashlist.tail
@@ -949,7 +1026,7 @@ function symbLookup _
 	if( imp_chain <> NULL ) then
 
 		if( firstglobal ) then
-			'' If we have found both imports and a global, then check the import.
+			'' If we have found both imports and a global, then check the imports.
 			'' If the import is actually a member of an  enum, then we'd prefer to
 			'' return the global instead. If the anonymous enum is not the first 
 			'' listed in the chain, then assume that the symbFindBy*() calls will

tests/pp/pragma-lookup108.bas

@@ -0,0 +1,13 @@
+' TEST_MODE : COMPILE_ONLY_OK
+
+'' syntax check
+
+#pragma push( lookup108 )
+#pragma push( lookup108, FALSE )
+#pragma push( lookup108, TRUE )
+#pragma pop( lookup108 )
+#pragma pop( lookup108 )
+#pragma pop( lookup108 )
+#pragma lookup108
+#pragma lookup108 = FALSE
+#pragma lookup108 = TRUE