提交 c92a30bd 编写于 作者: K kamg

7020118: Alter frame assignability to allow for exception handler coverage of invokespecial <init>

Summary: Add special rule to allow assignment of frames with uninit flags set.
Reviewed-by: never, coleenp
上级 2b06608f
......@@ -170,6 +170,44 @@ bool StackMapFrame::is_assignable_to(
return true;
}
bool StackMapFrame::has_flag_match_exception(
const StackMapFrame* target) const {
// We allow flags of {UninitThis} to assign to {} if-and-only-if the
// target frame does not depend upon the current type.
// This is slightly too strict, as we need only enforce that the
// slots that were initialized by the <init> (the things that were
// UninitializedThis before initialize_object() converted them) are unused.
// However we didn't save that information so we'll enforce this upon
// anything that might have been initialized. This is a rare situation
// and javac never generates code that would end up here, but some profilers
// (such as NetBeans) might, when adding exception handlers in <init>
// methods to cover the invokespecial instruction. See 7020118.
assert(max_locals() == target->max_locals() &&
stack_size() == target->stack_size(), "StackMap sizes must match");
VerificationType top = VerificationType::top_type();
VerificationType this_type = verifier()->current_type();
if (!flag_this_uninit() || target->flags() != 0) {
return false;
}
for (int i = 0; i < target->locals_size(); ++i) {
if (locals()[i] == this_type && target->locals()[i] != top) {
return false;
}
}
for (int i = 0; i < target->stack_size(); ++i) {
if (stack()[i] == this_type && target->stack()[i] != top) {
return false;
}
}
return true;
}
bool StackMapFrame::is_assignable_to(const StackMapFrame* target, TRAPS) const {
if (_max_locals != target->max_locals() || _stack_size != target->stack_size()) {
return false;
......@@ -182,7 +220,9 @@ bool StackMapFrame::is_assignable_to(const StackMapFrame* target, TRAPS) const {
bool match_stack = is_assignable_to(
_stack, target->stack(), _stack_size, CHECK_false);
bool match_flags = (_flags | target->flags()) == target->flags();
return (match_locals && match_stack && match_flags);
return match_locals && match_stack &&
(match_flags || has_flag_match_exception(target));
}
VerificationType StackMapFrame::pop_stack_ex(VerificationType type, TRAPS) {
......
......@@ -228,6 +228,8 @@ class StackMapFrame : public ResourceObj {
bool is_assignable_to(
VerificationType* src, VerificationType* target, int32_t len, TRAPS) const;
bool has_flag_match_exception(const StackMapFrame* target) const;
// Debugging
void print() const PRODUCT_RETURN;
};
......
......@@ -128,6 +128,7 @@ class VerificationType VALUE_OBJ_CLASS_SPEC {
// Create verification types
static VerificationType bogus_type() { return VerificationType(Bogus); }
static VerificationType top_type() { return bogus_type(); } // alias
static VerificationType null_type() { return VerificationType(Null); }
static VerificationType integer_type() { return VerificationType(Integer); }
static VerificationType float_type() { return VerificationType(Float); }
......
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