[CHERI_CSA] AllocationChecker: suppress for flexible array

Author: eupharina

clang/lib/StaticAnalyzer/Checkers/CHERI/AllocationChecker.cpp

@@ -107,8 +107,14 @@ bool relatedTypes(const Type *Ty1, const Type *Ty2) {
 bool reportForType(QualType Ty) {
   if (Ty->isVoidPointerType())
     return false;
-  if (Ty->isPointerType() || Ty->isArrayType())
-    return !Ty->getPointeeOrArrayElementType()->isCharType();
+  if (Ty->isPointerType() || Ty->isArrayType()) {
+    const Type *PTy = Ty->getPointeeOrArrayElementType();
+    if (PTy->isCharType())
+      return false;
+    if (PTy->isStructureTypeWithFlexibleArrayMember())
+      return false;
+    return true;
+  }
   return false;
 }
 

clang/test/Analysis/Checkers/CHERI/allocation.c

@@ -51,3 +51,14 @@ struct S2 * first_field(void *p, int n1) {
   struct S2 *p2 = (struct S2 *)(p3+n1); // no warn
   return p2;
 }
+
+struct S4 {
+  long len;
+  int buf[];
+};
+
+int* flex_array(int len) {
+  struct S4 *p = malloc(sizeof(struct S4) + len*sizeof(int));
+  int *pB = (int*)(p + 1); // no warn
+  return pB;
+}