src/hotspot/share/memory/allocation.cpp

rev 52793 : imported patch fix
rev 52794 : imported patch assign_assert

@@ -184,11 +184,16 @@
     allocation_type type = (allocation_type)(_allocation_t[1] & allocation_mask);
     return get_allocation_type()  == type &&
            (_allocation_t[1] - type) == (uintptr_t)(&_allocation_t[1]);
 }
 
-ResourceObj::ResourceObj() { // default constructor
+// This whole business of passing information from ResourceObj::operator new
+// to the ResourceObj constructor via fields in the "object" is technically UB.
+// But it seems to work within the limitations of HotSpot usage (such as no
+// multiple inheritance) with the compilers and compiler options we're using.
+// And it gives some possibly useful checking for misuse of ResourceObj.
+void ResourceObj::initialize_allocation_info() {
     if (~(_allocation_t[0] | allocation_mask) != (uintptr_t)this) {
       // Operator new() is not called for allocations
       // on stack and for embedded objects.
       set_allocation_type((address)this, STACK_OR_EMBEDDED);
     } else if (allocated_on_stack()) { // STACK_OR_EMBEDDED

@@ -208,22 +213,20 @@
       set_allocation_type((address)this, STACK_OR_EMBEDDED);
     }
     _allocation_t[1] = 0; // Zap verification value
 }
 
-ResourceObj::ResourceObj(const ResourceObj& r) { // default copy constructor
-    // Used in ClassFileParser::parse_constant_pool_entries() for ClassFileStream.
-    // Note: garbage may resembles valid value.
-    assert(~(_allocation_t[0] | allocation_mask) != (uintptr_t)this || !is_type_set(),
-           "embedded or stack only, this(" PTR_FORMAT ") type %d a[0]=(" PTR_FORMAT ") a[1]=(" PTR_FORMAT ")",
-           p2i(this), get_allocation_type(), _allocation_t[0], _allocation_t[1]);
-    set_allocation_type((address)this, STACK_OR_EMBEDDED);
-    _allocation_t[1] = 0; // Zap verification value
+ResourceObj::ResourceObj() {
+    initialize_allocation_info();
+}
+
+ResourceObj::ResourceObj(const ResourceObj&) {
+    // Initialize _allocation_t as a new object, ignoring object being copied.
+    initialize_allocation_info();
 }
 
-ResourceObj& ResourceObj::operator=(const ResourceObj& r) { // default copy assignment
-    // Used in InlineTree::ok_to_inline() for WarmCallInfo.
+ResourceObj& ResourceObj::operator=(const ResourceObj& r) {
     assert(allocated_on_stack(),
            "copy only into local, this(" PTR_FORMAT ") type %d a[0]=(" PTR_FORMAT ") a[1]=(" PTR_FORMAT ")",
            p2i(this), get_allocation_type(), _allocation_t[0], _allocation_t[1]);
     // Keep current _allocation_t value;
     return *this;