1 /*
   2  * Copyright (c) 2003, 2012, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_CLASSFILE_STACKMAPFRAME_HPP
  26 #define SHARE_VM_CLASSFILE_STACKMAPFRAME_HPP
  27 
  28 #include "classfile/verificationType.hpp"
  29 #include "classfile/verifier.hpp"
  30 #include "oops/methodOop.hpp"
  31 #include "runtime/handles.hpp"
  32 #include "runtime/signature.hpp"
  33 #include "utilities/exceptions.hpp"
  34 
  35 // A StackMapFrame represents one frame in the stack map attribute.
  36 
  37 class TypeContext;
  38 
  39 enum {
  40   FLAG_THIS_UNINIT = 0x01
  41 };
  42 
  43 class StackMapFrame : public ResourceObj {
  44  private:
  45   int32_t _offset;
  46 
  47   // See comment in StackMapTable about _frame_count about why these
  48   // fields are int32_t instead of u2.
  49   int32_t _locals_size;  // number of valid type elements in _locals
  50   int32_t _stack_size;   // number of valid type elements in _stack
  51 
  52   int32_t _stack_mark;   // Records the size of the stack prior to an
  53                          // instruction modification, to allow rewinding
  54                          // when/if an error occurs.
  55 
  56   int32_t _max_locals;
  57   int32_t _max_stack;
  58 
  59   u1 _flags;
  60   VerificationType* _locals; // local variable type array
  61   VerificationType* _stack;  // operand stack type array
  62 
  63   ClassVerifier* _verifier;  // the verifier verifying this method
  64 
  65   StackMapFrame(const StackMapFrame& cp) :
  66       _offset(cp._offset), _locals_size(cp._locals_size),
  67       _stack_size(cp._stack_size), _stack_mark(cp._stack_mark),
  68       _max_locals(cp._max_locals), _max_stack(cp._max_stack),
  69       _flags(cp._flags) {
  70     _locals = NEW_RESOURCE_ARRAY(VerificationType, _max_locals);
  71     for (int i = 0; i < _max_locals; ++i) {
  72       if (i < _locals_size) {
  73         _locals[i] = cp._locals[i];
  74       } else {
  75         _locals[i] = VerificationType::bogus_type();
  76       }
  77     }
  78     int ss = MAX2(_stack_size, _stack_mark);
  79     _stack = NEW_RESOURCE_ARRAY(VerificationType, _max_stack);
  80     for (int i = 0; i < _max_stack; ++i) {
  81       if (i < ss) {
  82         _stack[i] = cp._stack[i];
  83       } else {
  84         _stack[i] = VerificationType::bogus_type();
  85       }
  86     }
  87     _verifier = NULL;
  88   }
  89 
  90  public:
  91   // constructors
  92 
  93   // This constructor is used by the type checker to allocate frames
  94   // in type state, which have _max_locals and _max_stack array elements
  95   // in _locals and _stack.
  96   StackMapFrame(u2 max_locals, u2 max_stack, ClassVerifier* verifier);
  97 
  98   // This constructor is used to initialize stackmap frames in stackmap table,
  99   // which have _locals_size and _stack_size array elements in _locals and _stack.
 100   StackMapFrame(int32_t offset,
 101                 u1 flags,
 102                 u2 locals_size,
 103                 u2 stack_size,
 104                 u2 max_locals,
 105                 u2 max_stack,
 106                 VerificationType* locals,
 107                 VerificationType* stack,
 108                 ClassVerifier* v) : _offset(offset), _flags(flags),
 109                                     _locals_size(locals_size),
 110                                     _stack_size(stack_size),
 111                                     _stack_mark(-1),
 112                                     _max_locals(max_locals),
 113                                     _max_stack(max_stack),
 114                                     _locals(locals), _stack(stack),
 115                                     _verifier(v) { }
 116 
 117   static StackMapFrame* copy(StackMapFrame* smf) {
 118     return new StackMapFrame(*smf);
 119   }
 120 
 121   inline void set_offset(int32_t offset)      { _offset = offset; }
 122   inline void set_verifier(ClassVerifier* v)  { _verifier = v; }
 123   inline void set_flags(u1 flags)             { _flags = flags; }
 124   inline void set_locals_size(u2 locals_size) { _locals_size = locals_size; }
 125   inline void set_stack_size(u2 stack_size)   { _stack_size = _stack_mark = stack_size; }
 126   inline void clear_stack()                   { _stack_size = 0; }
 127   inline int32_t offset()   const             { return _offset; }
 128   inline ClassVerifier* verifier() const      { return _verifier; }
 129   inline u1 flags() const                     { return _flags; }
 130   inline int32_t locals_size() const          { return _locals_size; }
 131   inline VerificationType* locals() const     { return _locals; }
 132   inline int32_t stack_size() const           { return _stack_size; }
 133   inline VerificationType* stack() const      { return _stack; }
 134   inline int32_t max_locals() const           { return _max_locals; }
 135   inline int32_t max_stack() const            { return _max_stack; }
 136   inline bool flag_this_uninit() const        { return _flags & FLAG_THIS_UNINIT; }
 137 
 138   // Set locals and stack types to bogus
 139   inline void reset() {
 140     int32_t i;
 141     for (i = 0; i < _max_locals; i++) {
 142       _locals[i] = VerificationType::bogus_type();
 143     }
 144     for (i = 0; i < _max_stack; i++) {
 145       _stack[i] = VerificationType::bogus_type();
 146     }
 147   }
 148 
 149   // Return a StackMapFrame with the same local variable array and empty stack.
 150   // Stack array is allocate with unused one element.
 151   StackMapFrame* frame_in_exception_handler(u1 flags);
 152 
 153   // Set local variable type array based on m's signature.
 154   VerificationType set_locals_from_arg(
 155     const methodHandle m, VerificationType thisKlass, TRAPS);
 156 
 157   // Search local variable type array and stack type array.
 158   // Return true if an uninitialized object is found.
 159   bool has_new_object() const;
 160 
 161   // Search local variable type array and stack type array.
 162   // Set every element with type of old_object to new_object.
 163   void initialize_object(
 164     VerificationType old_object, VerificationType new_object);
 165 
 166   // Copy local variable type array in src into this local variable type array.
 167   void copy_locals(const StackMapFrame* src);
 168 
 169   // Copy stack type array in src into this stack type array.
 170   void copy_stack(const StackMapFrame* src);
 171 
 172   // Return true if this stack map frame is assignable to target.
 173   bool is_assignable_to(
 174       const StackMapFrame* target, bool is_exception_handler,
 175       ErrorContext* ctx, TRAPS) const;
 176 
 177   inline void set_mark() {
 178 #ifdef DEBUG
 179     // Put bogus type to indicate it's no longer valid.
 180     if (_stack_mark != -1) {
 181       for (int i = _stack_mark; i >= _stack_size; --i) {
 182         _stack[i] = VerificationType::bogus_type();
 183       }
 184     }
 185 #endif // def DEBUG
 186     _stack_mark = _stack_size;
 187   }
 188 
 189   // Used when an error occurs and we want to reset the stack to the state
 190   // it was before operands were popped off.
 191   void restore() {
 192     if (_stack_mark != -1) {
 193       _stack_size = _stack_mark;
 194     }
 195   }
 196 
 197   // Push type into stack type array.
 198   inline void push_stack(VerificationType type, TRAPS) {
 199     assert(!type.is_check(), "Must be a real type");
 200     if (_stack_size >= _max_stack) {
 201       verifier()->verify_error(
 202           ErrorContext::stack_overflow(_offset, this),
 203           "Operand stack overflow");
 204       return;
 205     }
 206     _stack[_stack_size++] = type;
 207   }
 208 
 209   inline void push_stack_2(
 210       VerificationType type1, VerificationType type2, TRAPS) {
 211     assert(type1.is_long() || type1.is_double(), "must be long/double");
 212     assert(type2.is_long2() || type2.is_double2(), "must be long/double_2");
 213     if (_stack_size >= _max_stack - 1) {
 214       verifier()->verify_error(
 215           ErrorContext::stack_overflow(_offset, this),
 216           "Operand stack overflow");
 217       return;
 218     }
 219     _stack[_stack_size++] = type1;
 220     _stack[_stack_size++] = type2;
 221   }
 222 
 223   // Pop and return the top type on stack without verifying.
 224   inline VerificationType pop_stack(TRAPS) {
 225     if (_stack_size <= 0) {
 226       verifier()->verify_error(
 227           ErrorContext::stack_underflow(_offset, this),
 228           "Operand stack underflow");
 229       return VerificationType::bogus_type();
 230     }
 231     VerificationType top = _stack[--_stack_size];
 232     return top;
 233   }
 234 
 235   // Pop and return the top type on stack type array after verifying it
 236   // is assignable to type.
 237   inline VerificationType pop_stack(VerificationType type, TRAPS) {
 238     if (_stack_size != 0) {
 239       VerificationType top = _stack[_stack_size - 1];
 240       bool subtype = type.is_assignable_from(
 241         top, verifier(), CHECK_(VerificationType::bogus_type()));
 242       if (subtype) {
 243         --_stack_size;
 244         return top;
 245       }
 246     }
 247     return pop_stack_ex(type, THREAD);
 248   }
 249 
 250   inline void pop_stack_2(
 251       VerificationType type1, VerificationType type2, TRAPS) {
 252     assert(type1.is_long2() || type1.is_double2(), "must be long/double");
 253     assert(type2.is_long() || type2.is_double(), "must be long/double_2");
 254     if (_stack_size >= 2) {
 255       VerificationType top1 = _stack[_stack_size - 1];
 256       bool subtype1 = type1.is_assignable_from(top1, verifier(), CHECK);
 257       VerificationType top2 = _stack[_stack_size - 2];
 258       bool subtype2 = type2.is_assignable_from(top2, verifier(), CHECK);
 259       if (subtype1 && subtype2) {
 260         _stack_size -= 2;
 261         return;
 262       }
 263     }
 264     pop_stack_ex(type1, THREAD);
 265     pop_stack_ex(type2, THREAD);
 266   }
 267 
 268   VerificationType local_at(int index) {
 269     return _locals[index];
 270   }
 271 
 272   VerificationType stack_at(int index) {
 273     return _stack[index];
 274   }
 275 
 276   // Uncommon case that throws exceptions.
 277   VerificationType pop_stack_ex(VerificationType type, TRAPS);
 278 
 279   // Return the type at index in local variable array after verifying
 280   // it is assignable to type.
 281   VerificationType get_local(int32_t index, VerificationType type, TRAPS);
 282   // For long/double.
 283   void get_local_2(
 284     int32_t index, VerificationType type1, VerificationType type2, TRAPS);
 285 
 286   // Set element at index in local variable array to type.
 287   void set_local(int32_t index, VerificationType type, TRAPS);
 288   // For long/double.
 289   void set_local_2(
 290     int32_t index, VerificationType type1, VerificationType type2, TRAPS);
 291 
 292   // Private auxiliary method used only in is_assignable_to(StackMapFrame).
 293   // Returns true if src is assignable to target.
 294   int is_assignable_to(
 295     VerificationType* src, VerificationType* target, int32_t len, TRAPS) const;
 296 
 297   bool has_flag_match_exception(const StackMapFrame* target) const;
 298 
 299   TypeOrigin stack_top_ctx();
 300 
 301   void print_on(outputStream* str) const;
 302 };
 303 
 304 #endif // SHARE_VM_CLASSFILE_STACKMAPFRAME_HPP