Merge pull request #90 from jayrm/cast-conv-ptr

Casting, Conversions, Const Qualifiers, Byref
Revision 145c13f to 8e8801b
Fixes for:
	- https://sourceforge.net/p/fbc/bugs/642 Pointer casting allows constness dropping 
	- https://sourceforge.net/p/fbc/bugs/886 Inconsistent error with BYREF and CAST on CONST variables 
	- https://sourceforge.net/p/fbc/bugs/801 parser allows more constructs under -exx than without it
	- https://sourceforge.net/p/fbc/bugs/880 Overload binary operators do not support covariant arguments
	- https://sourceforge.net/p/fbc/bugs/727 RTL functions not checking Constness unless marked RTL_CONST

Author: jayrm

changelog.txt

@@ -5,6 +5,8 @@ Version 1.06.0
 - test-suite uses libfbcunit for unit testing framework
 - SELECT CASE AS CONST respects data type and will show overflow warnings on out-of-range constants
 - boolean: don't allow NEG unary op '-' on boolean data types
+- All fb RTL functions are checked for CONSTness, CONST qualifiers added to fb rtlib built-in prototypes (sf.net #727)
+- WSTRING can be a return type, but only for prototypes (DECLARE) and function pointers, this allows getting PROCPTR() of all fb built-in run time functions
 
 [added]
 - -noobjinfo option to disable the writing/reading of compile-time library and other linking options from/to .o and .a files. This also disables the use of fbextra.x (the supplemental linker script) for discarding the .fbctinf sections, which is useful when using the gold linker that doesn't support this kind of linker script.
@@ -15,6 +17,8 @@ Version 1.06.0
 - Updated bindings: SDL2 2.0.6, SDL2_image 2.0.1, SDL2_mixer 2.0.1, SDL2_net 2.0.1, SDL2_ttf 2.0.14
 - allow overload operator SQR()
 - allow [static] shared byref variables to be initialized with byref variable
+- warning '-w constness' to enable 'CONST qualifier discarded' warning on command line
+- #pragma constness to enable/disable 'CONST qualifier discarded' warning in source code
 
 [fixed]
 - win/d3dx9.bi no longer has a hard-coded #inclib "d3dx9d". d3dx9d.dll is apparently not a generally valid choice. In practice programs have to be linked against d3dx9_33.dll or d3dx9_39.dll, etc.
@@ -65,6 +69,9 @@ Version 1.06.0
 - #822, #814, #842: Compiler crash when initializing static/shared reference (DIM SHARED/STATIC BYREF) with non-constant initializer (e.g. another reference, or dynamic array element)
 - ASM backend: Fix bad code generated for comparisons such as IF @globalvar = 0 THEN
 - #884: FORMATing dates can deadlock under Unix
+- #642, #886: CASTs involving CONST qualifiers solved out too early allowing invalid statements to be compiled
+- #801: *@(expr) solved to (expr) did not cleanly remove null ptr checks allowing invalid datatype assignment with -exx.  *PTRCHK(@expr) solves to (expr).
+- #880: Overload binary operators now support covariant arguments, overloaded procedure resolution changed especially with respect to CONST and non-CONST parameters
 
 
 Version 1.05.0

src/compiler/ast-helper.bas

@@ -190,7 +190,19 @@ function astBuildDerefAddrOf overload _
 		n = astNewBOP( AST_OP_ADD, n, offsetexpr )
 	end if
 
-	n = astNewCONV( typeAddrOf( dtype ), subtype, n, AST_CONVOPT_DONTCHKPTR )
+	'' Don't warn on CONST qualifier changes, astBuildDerefAddrOf() is only 
+	'' called for internal expressions in:
+	''		- astBuildVarField(), 
+	''		- hShallowCopy()
+	''		- hCallCtorList()
+	''		- cDynamicArrayIndex()
+	''		- cVariableEx()
+	''		- hAssignDynamicArray()
+	'' Except:
+	''		- astTypeIniFlush(), HOWEVER, astNewASSIGN() does it's own 
+	''		  checks and calls astNewCONV()
+
+	n = astNewCONV( typeAddrOf( dtype ), subtype, n, AST_CONVOPT_DONTCHKPTR or AST_CONVOPT_DONTWARNCONST )
 	n = astNewDEREF( n )
 
 	if( maybeafield ) then
@@ -998,7 +1010,8 @@ function astBuildStrPtr( byval lhs as ASTNODE ptr ) as ASTNODE ptr
 	dtype = typeSetIsConst( typeAddrOf( dtype ) )
 	dtype = typeAddrOf( dtype )
 
-	expr = astNewDEREF( astNewCONV( dtype, NULL, astNewADDROF( lhs ) ) )
+	'' Don't warn on CONST qualifier changes, we are explicitly forcing the conversion
+	expr = astNewDEREF( astNewCONV( dtype, NULL, astNewADDROF( lhs ), AST_CONVOPT_DONTWARNCONST ) )
 
 	return expr
 end function

src/compiler/ast-misc.bas

@@ -223,7 +223,7 @@ function astIsEqualParamInit _
 		'' symbols, but if they have the same signature they should still be
 		'' treated equal here.
 		if( typeGetDtOnly( l->dtype ) = FB_DATATYPE_FUNCTION ) then
-			if( symbCalcProcMatch( l->subtype, r->subtype, 0 ) = 0 ) then
+			if( symbCalcProcMatch( l->subtype, r->subtype, 0 ) = FB_OVLPROC_NO_MATCH ) then
 				exit function
 			end if
 		else
@@ -665,7 +665,7 @@ function astPtrCheck _
 	'' do this manually already (and if there is a CONSTness mismatch, they show an error,
 	'' not just a warning, which is astPtrCheck()'s main purpose).
 	function = (typeCalcMatch( typeGetDtAndPtrOnly( pdtype ), psubtype, pparammode, _
-	                           typeGetDtAndPtrOnly( edtype ), expr->subtype ) > 0)
+	                           typeGetDtAndPtrOnly( edtype ), expr->subtype ) > FB_OVLPROC_NO_MATCH)
 end function
 
 '':::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
@@ -985,7 +985,7 @@ sub astDtorListDump( )
 	print "-------------- dtorlist: ------------------"
 	i = listGetTail( @ast.dtorlist )
 	while( i )
-		print "    ";symbDump( i->sym );" cookie: ";i->cookie;" refcount: ";i->refcount;" has dtor? ";hHasDtor( i->sym )
+		print "    ";symbDumpToStr( i->sym );" cookie: ";i->cookie;" refcount: ";i->refcount;" has dtor? ";hHasDtor( i->sym )
 		i = listGetPrev( i )
 	wend
 end sub

src/compiler/ast-node-addr.bas

@@ -217,7 +217,8 @@ function astNewADDROF( byval l as ASTNODE ptr ) as ASTNODE ptr
 		if( t <> l ) then
 			astDelNode( l )  '' CONV that was skipped above
 		end if
-		return astNewCONV( dtype, subtype, n, AST_CONVOPT_DONTCHKPTR )
+		'' Don't warn CONST changes, we should have already got the warnings on previous CONV node's
+		return astNewCONV( dtype, subtype, n, AST_CONVOPT_DONTCHKPTR or AST_CONVOPT_DONTWARNCONST )
 	end if
 
 	'' alloc new node

src/compiler/ast-node-arg.bas

@@ -249,6 +249,8 @@ private sub hStrArgToStrPtrParam _
 			n->l = hAllocTmpString( parent, n->l, FALSE )
 		end if
 
+		'' *cast( [const] zstring const ptr ptr, @expr )
+		'' Don't worry about preserving CONST bits, astNewARG() should have checked.
 		n->l = astBuildStrPtr( n->l )
 
 	case FB_DATATYPE_FIXSTR
@@ -273,7 +275,8 @@ end sub
 
 sub hBuildByrefArg( byval param as FBSYMBOL ptr, byval n as ASTNODE ptr )
 	n->l = astNewADDROF( astRemoveNoConvCAST( n->l ) )
-	n->l = astNewCONV( typeAddrOf( symbGetFullType( param ) ), symbGetSubtype( param ), n->l )
+	'' Don't warn on CONST qualifier changes, astNewARG() should have checked
+	n->l = astNewCONV( typeAddrOf( symbGetFullType( param ) ), symbGetSubtype( param ), n->l, AST_CONVOPT_DONTWARNCONST )
 	assert( n->l )
 	n->arg.mode = FB_PARAMMODE_BYVAL
 end sub
@@ -1012,10 +1015,9 @@ function astNewARG _
 	'' a ctor that can't initialize the object would be useless, and after
 	'' dtors run the object is dead anyways, so modifications made by the
 	'' dtor don't matter)
-	if( ((symbGetIsRTL( sym ) = FALSE) or symbGetIsRTLConst( param )) and _
-	    ((not symbIsInstanceParam( param )) or _
+	if( ((not symbIsInstanceParam( param )) or _
 	     ((sym->attrib and FB_SYMBATTRIB_NOTHISCONSTNESS) = 0)) ) then
-		if( symbCheckConstAssign( symbGetFullType( param ), dtype, param->subtype, arg->subtype, symbGetParamMode( param ) ) = FALSE ) then
+		if( symbCheckConstAssignTopLevel( symbGetFullType( param ), dtype, param->subtype, arg->subtype, symbGetParamMode( param ) ) = FALSE ) then
 			if( symbIsInstanceParam( param ) ) then
 				errReportParam( parent->sym, 0, NULL, FB_ERRMSG_CONSTUDTTONONCONSTMETHOD )
 			else

src/compiler/ast-node-assign.bas

@@ -200,7 +200,7 @@ private function hCheckConstAndPointerOps _
 	function = FALSE
 
 	'' lhs marked CONST? disallow the assignment then.
-	if( symbCheckConstAssign( ldtype, rdtype, l->subtype, r->subtype ) = FALSE ) then
+	if( symbCheckConstAssignTopLevel( ldtype, rdtype, l->subtype, r->subtype ) = FALSE ) then
 		errReport( FB_ERRMSG_ILLEGALASSIGNMENT, TRUE )
 		exit function
 	end if
@@ -379,7 +379,7 @@ function astCheckByrefAssign _
 		byval lsubtype as FBSYMBOL ptr, _
 		byval r as ASTNODE ptr _
 	) as integer
-	function = (typeCalcMatch( ldtype, lsubtype, FB_PARAMMODE_BYREF, r->dtype, r->subtype ) > 0)
+	function = (typeCalcMatch( ldtype, lsubtype, FB_PARAMMODE_BYREF, r->dtype, r->subtype ) > FB_OVLPROC_NO_MATCH)
 end function
 
 private function hShallowCopy _

src/compiler/ast-node-call.bas

@@ -55,7 +55,7 @@ function astNewCALL _
 	''
 	if( ptrexpr ) then
 		assert( astGetDataType( ptrexpr ) = typeAddrOf( FB_DATATYPE_FUNCTION ) )
-		assert( (ptrexpr->subtype = sym) or (symbCalcProcMatch( ptrexpr->subtype, sym, 0 ) > 0) )
+		assert( (ptrexpr->subtype = sym) or (symbCalcProcMatch( ptrexpr->subtype, sym, 0 ) > FB_OVLPROC_NO_MATCH) )
 		sym = ptrexpr->subtype
 	end if
 

src/compiler/ast-node-conv.bas

@@ -305,7 +305,7 @@ function astNewCONV _
 	) as ASTNODE ptr
 
 	dim as ASTNODE ptr n = any
-	dim as integer ldclass = any, ldtype = any, errmsg = any, doconv = any
+	dim as integer ldclass = any, ldtype = any, errmsg = any, wrnmsg = any, doconv = any
 
 	if( perrmsg ) then
 		*perrmsg = FB_ERRMSG_OK
@@ -317,7 +317,7 @@ function astNewCONV _
 	if( typeGetDtAndPtrOnly( ldtype ) = typeGetDtAndPtrOnly( to_dtype ) ) then
 		if( l->subtype = to_subtype ) then
 			'' Only CONST bits changed?
-			if( ldtype <> to_dtype ) then
+			if( typeGetConstMask( ldtype ) <> typeGetConstMask( to_dtype ) ) then
 				'' CONST node? Evaluate at compile-time
 				if( astIsCONST( l ) ) then
 					astSetType( l, to_dtype, to_subtype )
@@ -327,8 +327,19 @@ function astNewCONV _
 					'' to the expression parser
 					n = astNewNode( AST_NODECLASS_CONV, to_dtype, to_subtype )
 					n->l = l
+
 					n->cast.doconv = FALSE
 					n->cast.do_convfd2fs = FALSE
+					
+					'' data types and levels of pointer inderection are the same,
+					'' always record this as const conversion
+					n->cast.convconst = TRUE
+
+					if( (options and AST_CONVOPT_DONTWARNCONST) = 0 ) then
+						if( fbPdCheckIsSet( FB_PDCHECK_CONSTNESS ) ) then
+							errReportWarn( FB_WARNINGMSG_CONSTQUALIFIERDISCARDED )
+						end if
+					end if
 				end if
 			else
 				n = l
@@ -472,6 +483,32 @@ function astNewCONV _
 	n->l = l
 	n->cast.doconv = doconv
 	n->cast.do_convfd2fs = FALSE
+	n->cast.convconst = FALSE
+
+	'' Discarding/changing const qualifier bits ?
+	if( typeIsPtr( ldtype ) and typeIsPtr( to_dtype ) ) then
+
+		wrnmsg = 0
+
+		n->cast.convconst = ( symbCheckConstAssign( to_dtype, ldtype, to_subtype, l->subtype, , , wrnmsg ) = FALSE )
+
+		'' else check if const conversion
+		if( n->cast.convconst ) then
+			if( (options and AST_CONVOPT_DONTWARNCONST) = 0 ) then
+				if( fbPdCheckIsSet( FB_PDCHECK_CONSTNESS ) ) then
+					'' specific warning message takes priority over const warning
+					if( wrnmsg = 0 ) then
+						wrnmsg = FB_WARNINGMSG_CONSTQUALIFIERDISCARDED
+					end if
+				end if
+			end if
+		end if
+	
+		'' warning? show it now
+		if( wrnmsg <> 0 ) then
+			errReportWarn( wrnmsg )
+		end if
+	end if
 
 	if( env.clopt.backend = FB_BACKEND_GAS ) then
 		if( doconv ) then
@@ -560,6 +597,14 @@ function astLoadCONV _
 
 	vs = astLoad( l )
 
+	'' n->cast
+	'' doconv convconst    do_convfd2fs
+	'' false  false        n/a           same size
+	'' false  true         n/a           same size - different const qualifiers, doesn't matter now
+	'' true   false        false         different sizes
+	'' true   false        true          convert floating point double to single
+	'' true   true         n/a           different sizes  - different const qualifiers, doesn't matter now
+
 	if( ast.doemit ) then
 		vs->vector = n->vector
 		if( n->cast.doconv ) then
@@ -593,7 +638,7 @@ end function
 function astSkipNoConvCAST( byval n as ASTNODE ptr ) as ASTNODE ptr
 	function = n
 	if( n->class = AST_NODECLASS_CONV ) then
-		if( n->cast.doconv = FALSE ) then
+		if( n->cast.doconv = FALSE and n->cast.convconst = FALSE ) then
 			function = n->l
 		end if
 	end if
@@ -602,7 +647,7 @@ end function
 function astRemoveNoConvCAST( byval n as ASTNODE ptr ) as ASTNODE ptr
 	function = n
 	if( n->class = AST_NODECLASS_CONV ) then
-		if( n->cast.doconv = FALSE ) then
+		if( n->cast.doconv = FALSE and n->cast.convconst = FALSE ) then
 			function = n->l
 			n->l = NULL
 			astDelTree( n )

src/compiler/ast-node-misc.bas

@@ -837,7 +837,7 @@ dim shared dbg_astNodeOpNames( 0 to AST_OPCODES - 1 ) as NameInfo = _
 	( /' @"AST_OP_TOUNSIGNED"      , '/ @"TOUNSIGNED"   /' , 0 '/ ) _
 }
 
-function astDumpOp( byval op as AST_OP ) as string
+function astDumpOpToStr( byval op as AST_OP ) as string
 	if(( op > AST_OPCODES - 1 ) or ( op < 0 )) then
 		return "OP:" + str(op)
 	end if
@@ -881,10 +881,10 @@ private function hAstNodeToStr _
 
 	select case as const n->class
 	case AST_NODECLASS_BOP
-		return astDumpOp( n->op.op ) & " =-= " & hSymbToStr( n->op.ex )
+		return astDumpOpToStr( n->op.op ) & " =-= " & hSymbToStr( n->op.ex )
 
 	case AST_NODECLASS_UOP
-		return astDumpOp( n->op.op )
+		return astDumpOpToStr( n->op.op )
 
 	case AST_NODECLASS_CONST
 		if( typeGetClass( n->dtype ) = FB_DATACLASS_FPOINT ) then
@@ -911,7 +911,7 @@ private function hAstNodeToStr _
 		return "LABEL: " & hSymbToStr( n->sym )
 
 	case AST_NODECLASS_BRANCH
-		return "BRANCH: " & astDumpOp( n->op.op ) & " " & hSymbToStr( n->op.ex )
+		return "BRANCH: " & astDumpOpToStr( n->op.op ) & " " & hSymbToStr( n->op.ex )
 
 	case AST_NODECLASS_SCOPEBEGIN
 		return "SCOPEBEGIN: " & hSymbToStr( n->sym )
@@ -947,7 +947,7 @@ private sub astDumpTreeEx _
 	's += "[" + hex( n, 8 ) + "] "
 	s += hAstNodeToStr( n )
 #if __FB_DEBUG__
-	s += " " + typeDump( n->dtype, n->subtype )
+	s += " " + typeDumpToStr( n->dtype, n->subtype )
 #endif
 	dbg_astOutput( s, col, just, depth )
 
@@ -1010,7 +1010,7 @@ function astDumpInline( byval n as ASTNODE ptr ) as string
 		s = "<NULL>"
 	else
 		s += hAstNodeClassToStr( n->class )
-		's += typeDump( n->dtype, n->subtype )
+		's += typeDumpToStr( n->dtype, n->subtype )
 
 		var have_data = (n->sym <> NULL) or (n->l <> NULL) or (n->r <> NULL)
 		select case as const( n->class )
@@ -1024,7 +1024,7 @@ function astDumpInline( byval n as ASTNODE ptr ) as string
 
 		select case as const( n->class )
 		case AST_NODECLASS_BOP, AST_NODECLASS_UOP
-			s += astDumpOp( n->op.op ) + ", "
+			s += astDumpOpToStr( n->op.op ) + ", "
 		case AST_NODECLASS_CONST
 			if( typeGetClass( n->dtype ) = FB_DATACLASS_FPOINT ) then
 				s += str( astConstGetFloat( n ) ) + ", "
@@ -1071,7 +1071,7 @@ sub astDumpSmall( byval n as ASTNODE ptr, byref prefix as string )
 	else
 		's += "[" + hex( n ) + "] "
 		s += hAstNodeClassToStr( n->class )
-		s += typeDump( n->dtype, n->subtype )
+		s += typeDumpToStr( n->dtype, n->subtype )
 
 		select case as const( n->class )
 		case AST_NODECLASS_MEM
@@ -1088,10 +1088,14 @@ sub astDumpSmall( byval n as ASTNODE ptr, byref prefix as string )
 		case AST_NODECLASS_IDX     : if( n->idx.ofs  ) then s += " ofs=" & n->idx.ofs
 			if( n->idx.mult <> 1 ) then s += " mult=" & n->idx.mult
 		case AST_NODECLASS_BOP, AST_NODECLASS_UOP
-			s += " " + astDumpOp( n->op.op )
+			s += " " + astDumpOpToStr( n->op.op )
 		case AST_NODECLASS_CONV
-			if( n->cast.doconv = FALSE ) then
+			if( n->cast.doconv = FALSE and n->cast.convconst = FALSE ) then
 				s += " noconv"
+			elseif( n->cast.doconv ) then
+				s += " conv"
+			elseif( n->cast.convconst ) then
+				s += " convconst"
 			end if
 		case AST_NODECLASS_CONST
 			if( typeGetClass( n->dtype ) = FB_DATACLASS_FPOINT ) then
@@ -1112,7 +1116,7 @@ sub astDumpSmall( byval n as ASTNODE ptr, byref prefix as string )
 					s += *n->sym->id.name
 				end if
 			#else
-				s += " " + symbDump( n->sym )
+				s += " " + symbDumpToStr( n->sym )
 			#endif
 		end if
 	end if

src/compiler/ast-node-ptr.bas

@@ -36,18 +36,44 @@ function astNewDEREF _
 
 			case AST_NODECLASS_OFFSET
 				delchild = (t->ofs.ofs = 0)
+			
+			case AST_NODECLASS_PTRCHK
+
+				'' convert *PTRCHK(@expr) to (expr)
+				'' TODO: remove null-ptr checks in ptr indexing
+
+				if( (t->l->class = AST_NODECLASS_ADDROF) or _
+					(t->l->class = AST_NODECLASS_OFFSET and t->l->ofs.ofs = 0) ) then
+
+					'' delete the null ptr check func call
+					astDelTree( t->r )	
+
+					'' move to ADDROF/OFFSET node
+					t = t->l
+
+					delchild = TRUE
+				else
+					delchild = FALSE
+				end if
 
 			case else
 				delchild = FALSE
 			end select
 
 			''
 			if( delchild ) then
+
 				n = t->l
-				astDelNode( t )
-				if( t <> l ) then
+
+				'' astSkipNoConvCAST() and removing the null pointer check
+				'' may have skipped multiple nodes
+				'' delete all nodes from L to T (up to but not including N)
+
+				while( l <> n )
+					t = l->l
 					astDelNode( l )
-				end if
+					l = t
+				wend
 
 				astSetType( n, dtype, subtype )
 				return n