Detect errors when dereferencing an undeclared variable.

Attempting to dereference an undeclared variable will cause an ICE.
Also attempting to pass an undeclared variable as an array of type
will also cause an ICE.  This patch detects both conditions and
generates an appropriate error.

gcc/m2/ChangeLog:

	* gm2-compiler/M2Quads.mod (AssignUnboundedVar): Check Type
	against NulSym and call MetaErrorT1 if necessary.
	(AssignUnboundedNonVar): Check Type against NulSym and
	call MetaErrorT1 if necessary.
	(BuildDesignatorPointer): Check Type1 against NulSym and
	call MetaErrorT1 if necessary.

Signed-off-by: Gaius Mulley <gaiusmod2@gmail.com>

diff --git a/gcc/m2/gm2-compiler/M2Quads.mod b/gcc/m2/gm2-compiler/M2Quads.mod
index 263fb7c..a58de93 100644 (file)
--- a/gcc/m2/gm2-compiler/M2Quads.mod
+++ b/gcc/m2/gm2-compiler/M2Quads.mod
@@ -6327,7 +6327,10 @@ BEGIN
    ELSIF IsVar(Sym)
    THEN
       Type := GetDType(Sym) ;
-      IF IsUnbounded(Type)
+      IF Type = NulSym
+      THEN
+         MetaErrorT1 (tok, '{%1ad} has no type and cannot be passed to a VAR formal parameter', Sym)
+      ELSIF IsUnbounded(Type)
       THEN
          IF Type = GetSType (UnboundedSym)
          THEN
@@ -6382,7 +6385,10 @@ BEGIN
    ELSIF IsVar (Sym)
    THEN
       Type := GetDType (Sym) ;
-      IF IsUnbounded (Type)
+      IF Type = NulSym
+      THEN
+         MetaErrorT1 (tok, '{%1ad} has no type and cannot be passed to a non VAR formal parameter', Sym)
+      ELSIF IsUnbounded (Type)
       THEN
          UnboundedNonVarLinkToArray (tok, Sym, ArraySym, UnboundedSym, ParamType, dim)
       ELSIF IsArray (Type) OR IsGenericSystemType (ParamType)
@@ -11386,7 +11392,10 @@ VAR
 BEGIN
    PopTFrwtok (Sym1, Type1, rw, exprtok) ;
    Type1 := SkipType (Type1) ;
-   IF IsUnknown (Sym1)
+   IF Type1 = NulSym
+   THEN
+      MetaErrorT1 (ptrtok, '{%1ad} has no type and therefore cannot be dereferenced by ^', Sym1)
+   ELSIF IsUnknown (Sym1)
    THEN
       MetaError1 ('{%1EMad} is undefined and therefore {%1ad}^ cannot be resolved', Sym1)
    ELSIF IsPointer (Type1)