fbc: g++ ABI - emit the deleting destructor

- emit the deleting destructor only in c++ mangling
- if type is in an extern "c++" block, implicitly generate and emit the deleting destructor (D0)

Author: jayrm

changelog.txt

@@ -46,6 +46,7 @@ Version 1.08.0
 - only write debug line information for statements and don't write comments / empty lines / directives for top level source code in assembly debug ouput
 - optimize byref 'm += s' string concatenations to fb_StrConcatByref() which will check for same string descriptor at run-time which can't be determined at compile time for byref parameters.
 - github #298: allow command line options passed to as, gcc, ld  to be longer than 128 characters by using string types internally
+- sf.net #923: implicitly emit the deleting destrutor for extern "c++" mangling for better g++ ABI compatibility
 
 [added]
 - extern "rtlib": respects the parent namespace, uses default fb calling convention and C style name mangling

src/compiler/ast-node-proc.bas

@@ -33,6 +33,7 @@ declare function hInitVptr _
 	) as ASTNODE ptr
 declare sub hCallCtors( byval n as ASTNODE ptr, byval sym as FBSYMBOL ptr )
 declare sub hCallDtors( byval proc as FBSYMBOL ptr )
+declare sub hCallDeleteDtor( byval proc as FBSYMBOL ptr )
 declare sub hGenStaticInstancesDtors( byval proc as FBSYMBOL ptr )
 declare sub hGenGlobalInstancesCtor( )
 
@@ -672,13 +673,18 @@ function astProcEnd( byval callrtexit as integer ) as integer
 	res = (symbCheckLabels(symbGetProcSymbTbHead(parser.currproc)) = 0)
 
 	if( res ) then
-		'' Destructor?
+		'' Complete Destructor?
 		if( symbIsDestructor1( sym ) and enable_implicit_code ) then
 			'' Call destructors, behind the exit label, so they'll
 			'' always be called, even with early returns.
 			hCallDtors( sym )
 		end if
 
+		'' Deleting Destructor?
+		if( symbIsDestructor0( sym ) and enable_implicit_code ) then
+			hCallDeleteDtor( sym )
+		end if
+
 		'' update proc's breaks list, adding calls to destructors when needed
 		if( n->block.breaklist.head <> NULL ) then
 			res = astScopeUpdBreakList( n )
@@ -1272,6 +1278,26 @@ private sub hCallFieldDtors _
 
 end sub
 
+private sub hCallDeleteDtor _
+	( _
+		byval proc as FBSYMBOL ptr _
+	)
+
+	dim as FBSYMBOL ptr parent = any, dtor1 = any, this_ = any
+	dim as ASTNODE ptr thisptr = any, tree = any
+
+	parent = symbGetNamespace( proc )
+	dtor1 = symbGetCompDtor1( parent )
+	if( dtor1 = NULL ) then
+		exit sub
+	end if
+	this_ = symbGetParamVar( symbGetProcHeadParam( proc ) )
+	thisptr = astNewADDROF( astBuildVarField( this_ ) )
+	tree = astBuildDeleteOp( AST_OP_DEL, thisptr )
+	astAdd( tree )
+
+end sub
+
 private sub hCallBaseDtor _
 	( _
 		byval parent as FBSYMBOL ptr, _

src/compiler/parser-proc.bas

@@ -1466,6 +1466,21 @@ function cProcHeader _
 			cOverrideAttribute( proc )
 		end if
 
+		'' destructor? maybe implicitly declare the deleting destructor too
+		if( tk = FB_TK_DESTRUCTOR ) then
+			'' fbc won't generate any code that calls the deleting destructor
+			'' so don't create the deleting destructor unless we're binding to c++
+			if( symbGetMangling( parent ) = FB_MANGLING_CPP ) then
+				'' - inherit all the attribs from the declared destructor
+				''   except for the destructor type
+				dim dtor0 as FBSYMBOL ptr = symbPreAddProc( NULL )
+				symbAddProcInstanceParam( parent, dtor0 )
+				pattrib and= not FB_PROCATTRIB_DESTRUCTOR1
+				pattrib or= FB_PROCATTRIB_DESTRUCTOR0
+				dtor0 = symbAddCtor( dtor0, NULL, attrib, pattrib, mode )
+			end if
+		end if
+
 		if( tk = FB_TK_PROPERTY ) then
 			hSetUdtPropertyFlags( parent, is_indexed, is_get )
 		end if

src/compiler/symb-comp.bas

@@ -621,19 +621,30 @@ sub symbUdtDeclareDefaultMembers _
 		'' no default dtor explicitly defined?
 		if( udt->udt.ext->dtor1 = NULL ) then
 
+			'' if we didn't have the complete dtor then we shouln't have the deleting dtor either
+			'' because there is no way to explicitly define the deleting dtor
 			assert( udt->udt.ext->dtor0 = NULL )
 
 			'' Complete dtor
 			default.dtor1 = hDeclareProc( udt, INVALID, FB_DATATYPE_INVALID, FB_SYMBATTRIB_NONE, FB_PROCATTRIB_DESTRUCTOR1 )
 
-			'' Deleting dtor
-			default.dtor0 = hDeclareProc( udt, INVALID, FB_DATATYPE_INVALID, FB_SYMBATTRIB_NONE, FB_PROCATTRIB_DESTRUCTOR0 )
+			if( symbGetMangling( udt ) = FB_MANGLING_CPP ) then
+				'' Deleting dtor
+				default.dtor0 = hDeclareProc( udt, INVALID, FB_DATATYPE_INVALID, FB_SYMBATTRIB_NONE, FB_PROCATTRIB_DESTRUCTOR0 )
+			end if
 
 			'' Don't allow the implicit dtor to override a FINAL dtor from the base
 			symbProcCheckOverridden( default.dtor1, TRUE )
 		end if
 	end if
 
+	if( symbGetMangling( udt ) = FB_MANGLING_CPP ) then
+		if( default.dtor0 = NULL ) then
+			'' deleting dtor will be implicitly declared if the complete dtor was explicitly declared
+			default.dtor0 = symbGetCompDtor0( udt )
+		end if
+	end if
+
 end sub
 
 '' Implement the implicit members declared by symbUdtDeclareDefaultMembers(),

src/compiler/symb-proc.bas

@@ -741,7 +741,6 @@ private function hSetupProc _
 			                      FB_SYMBCLASS_PROC, NULL, id_alias, _
 			                      FB_DATATYPE_VOID, NULL, attrib, pattrib )
 
-
 			'' ctor?
 			if( (pattrib and FB_PROCATTRIB_CONSTRUCTOR) <> 0 ) then
 				symbSetCompCtorHead( parent, proc )
@@ -753,9 +752,7 @@ private function hSetupProc _
 			'' deleting dtor
 			else
 				symbSetCompDtor0( parent, proc )
-
 			end if
-
 		'' otherwise, try to overload
 		else
 			'' dtor?
@@ -1612,7 +1609,7 @@ function symbFindCtorProc _
 	) as FBSYMBOL ptr
 
 	'' dtor? can't overload..
-	if( symbIsDestructor1( ovl_head_proc ) ) then
+	if( symbIsDestructor1( ovl_head_proc ) or symbIsDestructor0( ovl_head_proc ) ) then
 		return ovl_head_proc
 	else
 		return symbFindOverloadProc( ovl_head_proc, proc )

src/compiler/symb.bi

@@ -191,7 +191,7 @@ enum FB_PROCATTRIB
 	FB_PROCATTRIB_OVERLOADED       = &h00000001  '' PROCs / METHODs only
 	FB_PROCATTRIB_METHOD           = &h00000002  '' Non-STATIC UDT member procs, i.e. procs with implicit THIS ptr
 	FB_PROCATTRIB_CONSTRUCTOR      = &h00000004  '' methods only
-	FB_PROCATTRIB_DESTRUCTOR1      = &h00000008  '' methods only
+	FB_PROCATTRIB_DESTRUCTOR1      = &h00000008  '' methods only - complete destructor
 	FB_PROCATTRIB_OPERATOR         = &h00000010  '' methods only
 	FB_PROCATTRIB_PROPERTY         = &h00000020  '' methods only
 	FB_PROCATTRIB_STATICLOCALS     = &h00000040  '' PROCs only