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8012294: remove generic handling for default methods

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Reviewed-by: kamg, coleenp
This commit is contained in:
Karen Kinnear 2013-08-26 11:35:25 -04:00
parent 618cb11a73
commit 38560368c1
5 changed files with 10 additions and 2145 deletions
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367
hotspot/src/share/vm/classfile/defaultMethods.cpp
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@ -25,7 +25,6 @@
#include "precompiled.hpp"
#include "classfile/bytecodeAssembler.hpp"
#include "classfile/defaultMethods.hpp"
#include "classfile/genericSignatures.hpp"
#include "classfile/symbolTable.hpp"
#include "memory/allocation.hpp"
#include "memory/metadataFactory.hpp"
@ -75,14 +74,6 @@ class PseudoScope : public ResourceObj {
}
};
class ContextMark : public PseudoScopeMark {
private:
generic::Context::Mark _mark;
public:
ContextMark(const generic::Context::Mark& cm) : _mark(cm) {}
virtual void destroy() { _mark.destroy(); }
};
#ifndef PRODUCT
static void print_slot(outputStream* str, Symbol* name, Symbol* signature) {
ResourceMark rm;
@ -503,38 +494,6 @@ Symbol* MethodFamily::generate_conflicts_message(GrowableArray<Method*>* methods
return SymbolTable::new_symbol(ss.base(), (int)ss.size(), CHECK_NULL);
}
// A generic method family contains a set of all methods that implement a single
// language-level method. Because of erasure, these methods may have different
// signatures. As members of the set are collected while walking over the
// hierarchy, they are tagged with a qualification state. The qualification
// state for an erased method is set to disqualified if there exists a path
// from the root of hierarchy to the method that contains an interleaving
// language-equivalent method defined in an interface.
class GenericMethodFamily : public MethodFamily {
private:
generic::MethodDescriptor* _descriptor; // language-level description
public:
GenericMethodFamily(generic::MethodDescriptor* canonical_desc)
: _descriptor(canonical_desc) {}
generic::MethodDescriptor* descriptor() const { return _descriptor; }
bool descriptor_matches(generic::MethodDescriptor* md, generic::Context* ctx) {
return descriptor()->covariant_match(md, ctx);
}
#ifndef PRODUCT
Symbol* get_generic_sig() const {
generic::Context ctx(NULL); // empty, as _descriptor already canonicalized
TempNewSymbol sig = descriptor()->reify_signature(&ctx, Thread::current());
return sig;
}
#endif // ndef PRODUCT
};
class StateRestorer;
@ -571,26 +530,6 @@ class StatefulMethodFamily : public ResourceObj {
StateRestorer* record_method_and_dq_further(Method* mo);
};
// StatefulGenericMethodFamily is a wrapper around GenericMethodFamily that maintains the
// qualification state during hierarchy visitation, and applies that state
// when adding members to the GenericMethodFamily.
class StatefulGenericMethodFamily : public StatefulMethodFamily {
public:
StatefulGenericMethodFamily(generic::MethodDescriptor* md, generic::Context* ctx)
: StatefulMethodFamily(new GenericMethodFamily(md->canonicalize(ctx))) {
}
GenericMethodFamily* get_method_family() {
return (GenericMethodFamily*)_method_family;
}
bool descriptor_matches(generic::MethodDescriptor* md, generic::Context* ctx) {
return get_method_family()->descriptor_matches(md, ctx);
}
};
class StateRestorer : public PseudoScopeMark {
private:
StatefulMethodFamily* _method;
@ -616,39 +555,6 @@ StateRestorer* StatefulMethodFamily::record_method_and_dq_further(Method* mo) {
return mark;
}
class StatefulGenericMethodFamilies : public ResourceObj {
private:
GrowableArray<StatefulGenericMethodFamily*> _methods;
public:
StatefulGenericMethodFamily* find_matching(
generic::MethodDescriptor* md, generic::Context* ctx) {
for (int i = 0; i < _methods.length(); ++i) {
StatefulGenericMethodFamily* existing = _methods.at(i);
if (existing->descriptor_matches(md, ctx)) {
return existing;
}
}
return NULL;
}
StatefulGenericMethodFamily* find_matching_or_create(
generic::MethodDescriptor* md, generic::Context* ctx) {
StatefulGenericMethodFamily* method = find_matching(md, ctx);
if (method == NULL) {
method = new StatefulGenericMethodFamily(md, ctx);
_methods.append(method);
}
return method;
}
void extract_families_into(GrowableArray<GenericMethodFamily*>* array) {
for (int i = 0; i < _methods.length(); ++i) {
array->append(_methods.at(i)->get_method_family());
}
}
};
// Represents a location corresponding to a vtable slot for methods that
// neither the class nor any of it's ancestors provide an implementaion.
// Default methods may be present to fill this slot.
@ -779,146 +685,11 @@ class FindMethodsByErasedSig : public HierarchyVisitor<FindMethodsByErasedSig> {
};
// Iterates over the type hierarchy looking for all methods with a specific
// method name. The result of this is a set of method families each of
// which is populated with a set of methods that implement the same
// language-level signature.
class FindMethodsByGenericSig : public HierarchyVisitor<FindMethodsByGenericSig> {
private:
// Context data
Thread* THREAD;
generic::DescriptorCache* _cache;
Symbol* _method_name;
generic::Context* _ctx;
StatefulGenericMethodFamilies _families;
public:
FindMethodsByGenericSig(generic::DescriptorCache* cache, Symbol* name,
generic::Context* ctx, Thread* thread) :
_cache(cache), _method_name(name), _ctx(ctx), THREAD(thread) {}
void get_discovered_families(GrowableArray<GenericMethodFamily*>* methods) {
_families.extract_families_into(methods);
}
void* new_node_data(InstanceKlass* cls) { return new PseudoScope(); }
void free_node_data(void* node_data) {
PseudoScope::cast(node_data)->destroy();
}
bool visit() {
PseudoScope* scope = PseudoScope::cast(current_data());
InstanceKlass* klass = current_class();
InstanceKlass* sub = current_depth() > 0 ? class_at_depth(1) : NULL;
ContextMark* cm = new ContextMark(_ctx->mark());
scope->add_mark(cm); // will restore context when scope is freed
_ctx->apply_type_arguments(sub, klass, THREAD);
int start, end = 0;
start = klass->find_method_by_name(_method_name, &end);
if (start != -1) {
for (int i = start; i < end; ++i) {
Method* m = klass->methods()->at(i);
// This gets the method's parameter list with its generic type
// parameters resolved
generic::MethodDescriptor* md = _cache->descriptor_for(m, THREAD);
// Find all methods on this hierarchy that match this method
// (name, signature). This class collects other families of this
// method name.
StatefulGenericMethodFamily* family =
_families.find_matching_or_create(md, _ctx);
if (klass->is_interface()) {
// ???
StateRestorer* restorer = family->record_method_and_dq_further(m);
scope->add_mark(restorer);
} else {
// This is the rule that methods in classes "win" (bad word) over
// methods in interfaces. This works because of single inheritance
family->set_target_if_empty(m);
}
}
}
return true;
}
};
#ifndef PRODUCT
static void print_generic_families(
GrowableArray<GenericMethodFamily*>* methods, Symbol* match) {
streamIndentor si(tty, 4);
if (methods->length() == 0) {
tty->indent();
tty->print_cr("No Logical Method found");
}
for (int i = 0; i < methods->length(); ++i) {
tty->indent();
GenericMethodFamily* lm = methods->at(i);
if (lm->contains_signature(match)) {
tty->print_cr("<Matching>");
} else {
tty->print_cr("<Non-Matching>");
}
lm->print_sig_on(tty, lm->get_generic_sig(), 1);
}
}
#endif // ndef PRODUCT
static void create_overpasses(
GrowableArray<EmptyVtableSlot*>* slots, InstanceKlass* klass, TRAPS);
static void generate_generic_defaults(
InstanceKlass* klass, GrowableArray<EmptyVtableSlot*>* empty_slots,
EmptyVtableSlot* slot, int current_slot_index, TRAPS) {
if (slot->is_bound()) {
#ifndef PRODUCT
if (TraceDefaultMethods) {
streamIndentor si(tty, 4);
tty->indent().print_cr("Already bound to logical method:");
GenericMethodFamily* lm = (GenericMethodFamily*)(slot->get_binding());
lm->print_sig_on(tty, lm->get_generic_sig(), 1);
}
#endif // ndef PRODUCT
return; // covered by previous processing
}
generic::DescriptorCache cache;
generic::Context ctx(&cache);
FindMethodsByGenericSig visitor(&cache, slot->name(), &ctx, CHECK);
visitor.run(klass);
GrowableArray<GenericMethodFamily*> discovered_families;
visitor.get_discovered_families(&discovered_families);
#ifndef PRODUCT
if (TraceDefaultMethods) {
print_generic_families(&discovered_families, slot->signature());
}
#endif // ndef PRODUCT
// Find and populate any other slots that match the discovered families
for (int j = current_slot_index; j < empty_slots->length(); ++j) {
EmptyVtableSlot* open_slot = empty_slots->at(j);
if (slot->name() == open_slot->name()) {
for (int k = 0; k < discovered_families.length(); ++k) {
GenericMethodFamily* lm = discovered_families.at(k);
if (lm->contains_signature(open_slot->signature())) {
lm->determine_target(klass, CHECK);
open_slot->bind_family(lm);
}
}
}
}
}
static void generate_erased_defaults(
InstanceKlass* klass, GrowableArray<EmptyVtableSlot*>* empty_slots,
EmptyVtableSlot* slot, TRAPS) {
@ -943,21 +714,14 @@ static void merge_in_new_methods(InstanceKlass* klass,
//
// First if finds any name/signature slots that need any implementation (either
// because they are miranda or a superclass's implementation is an overpass
// itself). For each slot, iterate over the hierarchy, using generic signature
// information to partition any methods that match the name into method families
// where each family contains methods whose signatures are equivalent at the
// language level (i.e., their reified parameters match and return values are
// covariant). Check those sets to see if they contain a signature that matches
// the slot we're looking at (if we're lucky, there might be other empty slots
// that we can fill using the same analysis).
// itself). For each slot, iterate over the hierarchy, to see if they contain a
// signature that matches the slot we are looking at.
//
// For each slot filled, we generate an overpass method that either calls the
// unique default method candidate using invokespecial, or throws an exception
// (in the case of no default method candidates, or more than one valid
// candidate). These methods are then added to the class's method list. If
// the method set we're using contains methods (qualified or not) with a
// different runtime signature than the method we're creating, then we have to
// create bridges with those signatures too.
// candidate). These methods are then added to the class's method list.
// The JVM does not create bridges nor handle generic signatures here.
void DefaultMethods::generate_default_methods(
InstanceKlass* klass, GrowableArray<Method*>* mirandas, TRAPS) {
@ -997,11 +761,7 @@ void DefaultMethods::generate_default_methods(
}
#endif // ndef PRODUCT
if (ParseGenericDefaults) {
generate_generic_defaults(klass, empty_slots, slot, i, CHECK);
} else {
generate_erased_defaults(klass, empty_slots, slot, CHECK);
}
generate_erased_defaults(klass, empty_slots, slot, CHECK);
}
#ifndef PRODUCT
if (TraceDefaultMethods) {
@ -1019,13 +779,13 @@ void DefaultMethods::generate_default_methods(
}
/**
* Generic analysis was used upon interface '_target' and found a unique
* default method candidate with generic signature '_method_desc'. This
* Interface inheritance rules were used to find a unique default method
* candidate for the resolved class. This
* method is only viable if it would also be in the set of default method
* candidates if we ran a full analysis on the current class.
*
* The only reason that the method would not be in the set of candidates for
* the current class is if that there's another covariantly matching method
* the current class is if that there's another matching method
* which is "more specific" than the found method -- i.e., one could find a
* path in the interface hierarchy in which the matching method appears
* before we get to '_target'.
@ -1110,48 +870,6 @@ class ErasedShadowChecker : public ShadowChecker {
: ShadowChecker(thread, name, holder, target) {}
};
class GenericShadowChecker : public ShadowChecker {
private:
generic::DescriptorCache* _cache;
generic::MethodDescriptor* _method_desc;
bool path_has_shadow() {
generic::Context ctx(_cache);
for (int i = current_depth() - 1; i > 0; --i) {
InstanceKlass* ik = class_at_depth(i);
InstanceKlass* sub = class_at_depth(i + 1);
ctx.apply_type_arguments(sub, ik, THREAD);
if (ik->is_interface()) {
int end;
int start = ik->find_method_by_name(_method_name, &end);
if (start != -1) {
for (int j = start; j < end; ++j) {
Method* mo = ik->methods()->at(j);
generic::MethodDescriptor* md = _cache->descriptor_for(mo, THREAD);
if (_method_desc->covariant_match(md, &ctx)) {
return true;
}
}
}
}
}
return false;
}
public:
GenericShadowChecker(generic::DescriptorCache* cache, Thread* thread,
Symbol* name, InstanceKlass* holder, generic::MethodDescriptor* desc,
InstanceKlass* target)
: ShadowChecker(thread, name, holder, target) {
_cache = cache;
_method_desc = desc;
}
};
// Find the unique qualified candidate from the perspective of the super_class
// which is the resolved_klass, which must be an immediate superinterface
@ -1203,66 +921,6 @@ Method* find_erased_super_default(InstanceKlass* current_class, InstanceKlass* s
}
}
// super_class is assumed to be the direct super of current_class
Method* find_generic_super_default( InstanceKlass* current_class,
InstanceKlass* super_class,
Symbol* method_name, Symbol* sig, TRAPS) {
generic::DescriptorCache cache;
generic::Context ctx(&cache);
// Prime the initial generic context for current -> super_class
ctx.apply_type_arguments(current_class, super_class, CHECK_NULL);
FindMethodsByGenericSig visitor(&cache, method_name, &ctx, CHECK_NULL);
visitor.run(super_class);
GrowableArray<GenericMethodFamily*> families;
visitor.get_discovered_families(&families);
#ifndef PRODUCT
if (TraceDefaultMethods) {
print_generic_families(&families, sig);
}
#endif // ndef PRODUCT
GenericMethodFamily* selected_family = NULL;
for (int i = 0; i < families.length(); ++i) {
GenericMethodFamily* lm = families.at(i);
if (lm->contains_signature(sig)) {
lm->determine_target(current_class, CHECK_NULL);
selected_family = lm;
}
}
if (selected_family->has_target()) {
Method* target = selected_family->get_selected_target();
InstanceKlass* holder = InstanceKlass::cast(target->method_holder());
// Verify that the identified method is valid from the context of
// the current class
GenericShadowChecker checker(&cache, THREAD, target->name(),
holder, selected_family->descriptor(), super_class);
checker.run(current_class);
if (checker.found_shadow()) {
#ifndef PRODUCT
if (TraceDefaultMethods) {
tty->print_cr(" Only candidate found was shadowed.");
}
#endif // ndef PRODUCT
THROW_MSG_(vmSymbols::java_lang_AbstractMethodError(),
"Accessible default method not found", NULL);
} else {
return target;
}
} else {
assert(selected_family->throws_exception(), "must have target or throw");
THROW_MSG_(vmSymbols::java_lang_AbstractMethodError(),
selected_family->get_exception_message()->as_C_string(), NULL);
}
}
// This is called during linktime when we find an invokespecial call that
// refers to a direct superinterface. It indicates that we should find the
// default method in the hierarchy of that superinterface, and if that method
@ -1296,13 +954,8 @@ Method* DefaultMethods::find_super_default(
assert(super_class->is_interface(), "only call for default methods");
Method* target = NULL;
if (ParseGenericDefaults) {
target = find_generic_super_default(current_class, super_class,
method_name, sig, CHECK_NULL);
} else {
target = find_erased_super_default(current_class, super_class,
method_name, sig, CHECK_NULL);
}
target = find_erased_super_default(current_class, super_class,
method_name, sig, CHECK_NULL);
#ifndef PRODUCT
if (target != NULL) {