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/*
* Copyright 2003-2006 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*
*/
class StackMapReader;
// StackMapTable class is the StackMap table used by type checker
class StackMapTable : public StackObj {
private:
// Logically, the _frame_count (as well as many fields in the StackFrame)
// should be a u2, but if we defined the variable as that type it will
// be difficult to detect/recover from overflow or underflow conditions.
// Widening the type and making it signed will help detect these.
int32_t _code_length;
int32_t _frame_count; // Stackmap frame count
StackMapFrame** _frame_array;
public:
StackMapTable(StackMapReader* reader, StackMapFrame* init_frame,
u2 max_locals, u2 max_stack,
char* code_data, int code_len, TRAPS);
inline int32_t get_frame_count() const { return _frame_count; }
inline int get_offset(int index) const {
return _frame_array[index]->offset();
}
// Match and/or update current_frame to the frame in stackmap table with
// specified offset. Return true if the two frames match.
bool match_stackmap(
StackMapFrame* current_frame, int32_t offset,
bool match, bool update, TRAPS) const;
// Match and/or update current_frame to the frame in stackmap table with
// specified offset and frame index. Return true if the two frames match.
bool match_stackmap(
StackMapFrame* current_frame, int32_t offset, int32_t frame_index,
bool match, bool update, TRAPS) const;
// Check jump instructions. Make sure there are no uninitialized
// instances on backward branch.
void check_jump_target(StackMapFrame* frame, int32_t target, TRAPS) const;
// The following methods are only used inside this class.
// Returns the frame array index where the frame with offset is stored.
int get_index_from_offset(int32_t offset) const;
// Make sure that there's no uninitialized object exist on backward branch.
void check_new_object(
const StackMapFrame* frame, int32_t target, TRAPS) const;
// Debugging
void print() const PRODUCT_RETURN;
};
class StackMapStream : StackObj {
private:
typeArrayHandle _data;
int _index;
public:
StackMapStream(typeArrayHandle ah)
: _data(ah), _index(0) {
}
u1 get_u1(TRAPS) {
if (_data == NULL || _index >= _data->length()) {
stackmap_format_error("access beyond the end of attribute", CHECK_0);
}
return _data->byte_at(_index++);
}
u2 get_u2(TRAPS) {
if (_data == NULL || _index >= _data->length() - 1) {
stackmap_format_error("access beyond the end of attribute", CHECK_0);
}
u2 res = Bytes::get_Java_u2((u1*)_data->byte_at_addr(_index));
_index += 2;
return res;
}
bool at_end() {
return (_data == NULL) || (_index == _data->length());
}
static void stackmap_format_error(const char* msg, TRAPS);
};
class StackMapReader : StackObj {
private:
// information about the class and method
constantPoolHandle _cp;
ClassVerifier* _verifier;
StackMapStream* _stream;
char* _code_data;
int32_t _code_length;
// information get from the attribute
int32_t _frame_count; // frame count
int32_t chop(VerificationType* locals, int32_t length, int32_t chops);
VerificationType parse_verification_type(u1* flags, TRAPS);
void check_verification_type_array_size(
int32_t size, int32_t max_size, TRAPS) {
if (size < 0 || size > max_size) {
// Since this error could be caused someone rewriting the method
// but not knowing to update the stackmap data, we call the the
// verifier's error method, which may not throw an exception and
// failover to the old verifier instead.
_verifier->class_format_error(
"StackMapTable format error: bad type array size");
}
}
enum {
SAME_LOCALS_1_STACK_ITEM_EXTENDED = 247,
SAME_EXTENDED = 251,
FULL = 255
};
public:
// Constructor
StackMapReader(ClassVerifier* v, StackMapStream* stream, char* code_data,
int32_t code_len, TRAPS) :
_verifier(v), _stream(stream),
_code_data(code_data), _code_length(code_len) {
methodHandle m = v->method();
if (m->has_stackmap_table()) {
_cp = constantPoolHandle(THREAD, m->constants());
_frame_count = _stream->get_u2(CHECK);
} else {
// There's no stackmap table present. Frame count and size are 0.
_frame_count = 0;
}
}
inline int32_t get_frame_count() const { return _frame_count; }
StackMapFrame* next(StackMapFrame* pre_frame, bool first,
u2 max_locals, u2 max_stack, TRAPS);
void check_end(TRAPS) {
if (!_stream->at_end()) {
StackMapStream::stackmap_format_error("wrong attribute size", CHECK);
}
}
};
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