1 /*
   2  * Copyright 1997-2010 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  20  * CA 95054 USA or visit www.sun.com if you need additional information or
  21  * have any questions.
  22  *
  23  */
  24 
  25 class  CodeComments;
  26 class  AbstractAssembler;
  27 class  MacroAssembler;
  28 class  PhaseCFG;
  29 class  Compile;
  30 class  BufferBlob;
  31 class  CodeBuffer;
  32 
  33 class CodeOffsets: public StackObj {
  34 public:
  35   enum Entries { Entry,
  36                  Verified_Entry,
  37                  Frame_Complete, // Offset in the code where the frame setup is (for forte stackwalks) is complete
  38                  OSR_Entry,
  39                  Dtrace_trap = OSR_Entry,  // dtrace probes can never have an OSR entry so reuse it
  40                  Exceptions,     // Offset where exception handler lives
  41                  Deopt,          // Offset where deopt handler lives
  42                  DeoptMH,        // Offset where MethodHandle deopt handler lives
  43                  UnwindHandler,  // Offset to default unwind handler
  44                  max_Entries };
  45 
  46   // special value to note codeBlobs where profile (forte) stack walking is
  47   // always dangerous and suspect.
  48 
  49   enum { frame_never_safe = -1 };
  50 
  51 private:
  52   int _values[max_Entries];
  53 
  54 public:
  55   CodeOffsets() {
  56     _values[Entry         ] = 0;
  57     _values[Verified_Entry] = 0;
  58     _values[Frame_Complete] = frame_never_safe;
  59     _values[OSR_Entry     ] = 0;
  60     _values[Exceptions    ] = -1;
  61     _values[Deopt         ] = -1;
  62     _values[DeoptMH       ] = -1;
  63     _values[UnwindHandler ] = -1;
  64   }
  65 
  66   int value(Entries e) { return _values[e]; }
  67   void set_value(Entries e, int val) { _values[e] = val; }
  68 };
  69 
  70 // This class represents a stream of code and associated relocations.
  71 // There are a few in each CodeBuffer.
  72 // They are filled concurrently, and concatenated at the end.
  73 class CodeSection VALUE_OBJ_CLASS_SPEC {
  74   friend class CodeBuffer;
  75  public:
  76   typedef int csize_t;  // code size type; would be size_t except for history
  77 
  78  private:
  79   address     _start;           // first byte of contents (instructions)
  80   address     _mark;            // user mark, usually an instruction beginning
  81   address     _end;             // current end address
  82   address     _limit;           // last possible (allocated) end address
  83   relocInfo*  _locs_start;      // first byte of relocation information
  84   relocInfo*  _locs_end;        // first byte after relocation information
  85   relocInfo*  _locs_limit;      // first byte after relocation information buf
  86   address     _locs_point;      // last relocated position (grows upward)
  87   bool        _locs_own;        // did I allocate the locs myself?
  88   bool        _frozen;          // no more expansion of this section
  89   char        _index;           // my section number (SECT_INST, etc.)
  90   CodeBuffer* _outer;           // enclosing CodeBuffer
  91 
  92   // (Note:  _locs_point used to be called _last_reloc_offset.)
  93 
  94   CodeSection() {
  95     _start         = NULL;
  96     _mark          = NULL;
  97     _end           = NULL;
  98     _limit         = NULL;
  99     _locs_start    = NULL;
 100     _locs_end      = NULL;
 101     _locs_limit    = NULL;
 102     _locs_point    = NULL;
 103     _locs_own      = false;
 104     _frozen        = false;
 105     debug_only(_index = -1);
 106     debug_only(_outer = (CodeBuffer*)badAddress);
 107   }
 108 
 109   void initialize_outer(CodeBuffer* outer, int index) {
 110     _outer = outer;
 111     _index = index;
 112   }
 113 
 114   void initialize(address start, csize_t size = 0) {
 115     assert(_start == NULL, "only one init step, please");
 116     _start         = start;
 117     _mark          = NULL;
 118     _end           = start;
 119 
 120     _limit         = start + size;
 121     _locs_point    = start;
 122   }
 123 
 124   void initialize_locs(int locs_capacity);
 125   void expand_locs(int new_capacity);
 126   void initialize_locs_from(const CodeSection* source_cs);
 127 
 128   // helper for CodeBuffer::expand()
 129   void take_over_code_from(CodeSection* cs) {
 130     _start      = cs->_start;
 131     _mark       = cs->_mark;
 132     _end        = cs->_end;
 133     _limit      = cs->_limit;
 134     _locs_point = cs->_locs_point;
 135   }
 136 
 137  public:
 138   address     start() const         { return _start; }
 139   address     mark() const          { return _mark; }
 140   address     end() const           { return _end; }
 141   address     limit() const         { return _limit; }
 142   csize_t     size() const          { return (csize_t)(_end - _start); }
 143   csize_t     mark_off() const      { assert(_mark != NULL, "not an offset");
 144                                       return (csize_t)(_mark - _start); }
 145   csize_t     capacity() const      { return (csize_t)(_limit - _start); }
 146   csize_t     remaining() const     { return (csize_t)(_limit - _end); }
 147 
 148   relocInfo*  locs_start() const    { return _locs_start; }
 149   relocInfo*  locs_end() const      { return _locs_end; }
 150   int         locs_count() const    { return (int)(_locs_end - _locs_start); }
 151   relocInfo*  locs_limit() const    { return _locs_limit; }
 152   address     locs_point() const    { return _locs_point; }
 153   csize_t     locs_point_off() const{ return (csize_t)(_locs_point - _start); }
 154   csize_t     locs_capacity() const { return (csize_t)(_locs_limit - _locs_start); }
 155   csize_t     locs_remaining()const { return (csize_t)(_locs_limit - _locs_end); }
 156 
 157   int         index() const         { return _index; }
 158   bool        is_allocated() const  { return _start != NULL; }
 159   bool        is_empty() const      { return _start == _end; }
 160   bool        is_frozen() const     { return _frozen; }
 161   bool        has_locs() const      { return _locs_end != NULL; }
 162 
 163   CodeBuffer* outer() const         { return _outer; }
 164 
 165   // is a given address in this section?  (2nd version is end-inclusive)
 166   bool contains(address pc) const   { return pc >= _start && pc <  _end; }
 167   bool contains2(address pc) const  { return pc >= _start && pc <= _end; }
 168   bool allocates(address pc) const  { return pc >= _start && pc <  _limit; }
 169   bool allocates2(address pc) const { return pc >= _start && pc <= _limit; }
 170 
 171   void    set_end(address pc)       { assert(allocates2(pc),""); _end = pc; }
 172   void    set_mark(address pc)      { assert(contains2(pc),"not in codeBuffer");
 173                                       _mark = pc; }
 174   void    set_mark_off(int offset)  { assert(contains2(offset+_start),"not in codeBuffer");
 175                                       _mark = offset + _start; }
 176   void    set_mark()                { _mark = _end; }
 177   void    clear_mark()              { _mark = NULL; }
 178 
 179   void    set_locs_end(relocInfo* p) {
 180     assert(p <= locs_limit(), "locs data fits in allocated buffer");
 181     _locs_end = p;
 182   }
 183   void    set_locs_point(address pc) {
 184     assert(pc >= locs_point(), "relocation addr may not decrease");
 185     assert(allocates2(pc),     "relocation addr must be in this section");
 186     _locs_point = pc;
 187   }
 188 
 189   // Share a scratch buffer for relocinfo.  (Hacky; saves a resource allocation.)
 190   void initialize_shared_locs(relocInfo* buf, int length);
 191 
 192   // Manage labels and their addresses.
 193   address target(Label& L, address branch_pc);
 194 
 195   // Emit a relocation.
 196   void relocate(address at, RelocationHolder const& rspec, int format = 0);
 197   void relocate(address at,    relocInfo::relocType rtype, int format = 0) {
 198     if (rtype != relocInfo::none)
 199       relocate(at, Relocation::spec_simple(rtype), format);
 200   }
 201 
 202   // alignment requirement for starting offset
 203   // Requirements are that the instruction area and the
 204   // stubs area must start on CodeEntryAlignment, and
 205   // the ctable on sizeof(jdouble)
 206   int alignment() const             { return MAX2((int)sizeof(jdouble), (int)CodeEntryAlignment); }
 207 
 208   // Slop between sections, used only when allocating temporary BufferBlob buffers.
 209   static csize_t end_slop()         { return MAX2((int)sizeof(jdouble), (int)CodeEntryAlignment); }
 210 
 211   csize_t align_at_start(csize_t off) const { return (csize_t) align_size_up(off, alignment()); }
 212 
 213   // Mark a section frozen.  Assign its remaining space to
 214   // the following section.  It will never expand after this point.
 215   inline void freeze();         //  { _outer->freeze_section(this); }
 216 
 217   // Ensure there's enough space left in the current section.
 218   // Return true if there was an expansion.
 219   bool maybe_expand_to_ensure_remaining(csize_t amount);
 220 
 221 #ifndef PRODUCT
 222   void decode();
 223   void dump();
 224   void print(const char* name);
 225 #endif //PRODUCT
 226 };
 227 
 228 class CodeComment;
 229 class CodeComments VALUE_OBJ_CLASS_SPEC {
 230 private:
 231 #ifndef PRODUCT
 232   CodeComment* _comments;
 233 #endif
 234 
 235 public:
 236   CodeComments() {
 237 #ifndef PRODUCT
 238     _comments = NULL;
 239 #endif
 240   }
 241 
 242   void add_comment(intptr_t offset, const char * comment) PRODUCT_RETURN;
 243   void print_block_comment(outputStream* stream, intptr_t offset)  PRODUCT_RETURN;
 244   void assign(CodeComments& other)  PRODUCT_RETURN;
 245   void free() PRODUCT_RETURN;
 246 };
 247 
 248 
 249 // A CodeBuffer describes a memory space into which assembly
 250 // code is generated.  This memory space usually occupies the
 251 // interior of a single BufferBlob, but in some cases it may be
 252 // an arbitrary span of memory, even outside the code cache.
 253 //
 254 // A code buffer comes in two variants:
 255 //
 256 // (1) A CodeBuffer referring to an already allocated piece of memory:
 257 //     This is used to direct 'static' code generation (e.g. for interpreter
 258 //     or stubroutine generation, etc.).  This code comes with NO relocation
 259 //     information.
 260 //
 261 // (2) A CodeBuffer referring to a piece of memory allocated when the
 262 //     CodeBuffer is allocated.  This is used for nmethod generation.
 263 //
 264 // The memory can be divided up into several parts called sections.
 265 // Each section independently accumulates code (or data) an relocations.
 266 // Sections can grow (at the expense of a reallocation of the BufferBlob
 267 // and recopying of all active sections).  When the buffered code is finally
 268 // written to an nmethod (or other CodeBlob), the contents (code, data,
 269 // and relocations) of the sections are padded to an alignment and concatenated.
 270 // Instructions and data in one section can contain relocatable references to
 271 // addresses in a sibling section.
 272 
 273 class CodeBuffer: public StackObj {
 274   friend class CodeSection;
 275 
 276  private:
 277   // CodeBuffers must be allocated on the stack except for a single
 278   // special case during expansion which is handled internally.  This
 279   // is done to guarantee proper cleanup of resources.
 280   void* operator new(size_t size) { return ResourceObj::operator new(size); }
 281   void  operator delete(void* p)  {        ResourceObj::operator delete(p); }
 282 
 283  public:
 284   typedef int csize_t;  // code size type; would be size_t except for history
 285   enum {
 286     // Here is the list of all possible sections, in order of ascending address.
 287     SECT_INSTS,               // Executable instructions.
 288     SECT_STUBS,               // Outbound trampolines for supporting call sites.
 289     SECT_CONSTS,              // Non-instruction data:  Floats, jump tables, etc.
 290     SECT_LIMIT, SECT_NONE = -1
 291   };
 292 
 293  private:
 294   enum {
 295     sect_bits = 2,      // assert (SECT_LIMIT <= (1<<sect_bits))
 296     sect_mask = (1<<sect_bits)-1
 297   };
 298 
 299   const char*  _name;
 300 
 301   CodeSection  _insts;              // instructions (the main section)
 302   CodeSection  _stubs;              // stubs (call site support), deopt, exception handling
 303   CodeSection  _consts;             // constants, jump tables
 304 
 305   CodeBuffer*  _before_expand;  // dead buffer, from before the last expansion
 306 
 307   BufferBlob*  _blob;           // optional buffer in CodeCache for generated code
 308   address      _total_start;    // first address of combined memory buffer
 309   csize_t      _total_size;     // size in bytes of combined memory buffer
 310 
 311   OopRecorder* _oop_recorder;
 312   CodeComments _comments;
 313   OopRecorder  _default_oop_recorder;  // override with initialize_oop_recorder
 314   Arena*       _overflow_arena;
 315 
 316   address      _decode_begin;   // start address for decode
 317   address      decode_begin();
 318 
 319   void initialize_misc(const char * name) {
 320     // all pointers other than code_start/end and those inside the sections
 321     assert(name != NULL, "must have a name");
 322     _name            = name;
 323     _before_expand   = NULL;
 324     _blob            = NULL;
 325     _oop_recorder    = NULL;
 326     _decode_begin    = NULL;
 327     _overflow_arena  = NULL;
 328   }
 329 
 330   void initialize(address code_start, csize_t code_size) {
 331     _insts.initialize_outer(this,   SECT_INSTS);
 332     _stubs.initialize_outer(this,   SECT_STUBS);
 333     _consts.initialize_outer(this,  SECT_CONSTS);
 334     _total_start = code_start;
 335     _total_size  = code_size;
 336     // Initialize the main section:
 337     _insts.initialize(code_start, code_size);
 338     assert(!_stubs.is_allocated(),  "no garbage here");
 339     assert(!_consts.is_allocated(), "no garbage here");
 340     _oop_recorder = &_default_oop_recorder;
 341   }
 342 
 343   void initialize_section_size(CodeSection* cs, csize_t size);
 344 
 345   void freeze_section(CodeSection* cs);
 346 
 347   // helper for CodeBuffer::expand()
 348   void take_over_code_from(CodeBuffer* cs);
 349 
 350 #ifdef ASSERT
 351   // ensure sections are disjoint, ordered, and contained in the blob
 352   bool verify_section_allocation();
 353 #endif
 354 
 355   // copies combined relocations to the blob, returns bytes copied
 356   // (if target is null, it is a dry run only, just for sizing)
 357   csize_t copy_relocations_to(CodeBlob* blob) const;
 358 
 359   // copies combined code to the blob (assumes relocs are already in there)
 360   void copy_code_to(CodeBlob* blob);
 361 
 362   // moves code sections to new buffer (assumes relocs are already in there)
 363   void relocate_code_to(CodeBuffer* cb) const;
 364 
 365   // set up a model of the final layout of my contents
 366   void compute_final_layout(CodeBuffer* dest) const;
 367 
 368   // Expand the given section so at least 'amount' is remaining.
 369   // Creates a new, larger BufferBlob, and rewrites the code & relocs.
 370   void expand(CodeSection* which_cs, csize_t amount);
 371 
 372   // Helper for expand.
 373   csize_t figure_expanded_capacities(CodeSection* which_cs, csize_t amount, csize_t* new_capacity);
 374 
 375  public:
 376   // (1) code buffer referring to pre-allocated instruction memory
 377   CodeBuffer(address code_start, csize_t code_size);
 378 
 379   // (2) code buffer allocating codeBlob memory for code & relocation
 380   // info but with lazy initialization.  The name must be something
 381   // informative.
 382   CodeBuffer(const char* name) {
 383     initialize_misc(name);
 384   }
 385 
 386 
 387   // (3) code buffer allocating codeBlob memory for code & relocation
 388   // info.  The name must be something informative and code_size must
 389   // include both code and stubs sizes.
 390   CodeBuffer(const char* name, csize_t code_size, csize_t locs_size) {
 391     initialize_misc(name);
 392     initialize(code_size, locs_size);
 393   }
 394 
 395   ~CodeBuffer();
 396 
 397   // Initialize a CodeBuffer constructed using constructor 2.  Using
 398   // constructor 3 is equivalent to calling constructor 2 and then
 399   // calling this method.  It's been factored out for convenience of
 400   // construction.
 401   void initialize(csize_t code_size, csize_t locs_size);
 402 
 403   CodeSection* insts()             { return &_insts; }
 404   CodeSection* stubs()             { return &_stubs; }
 405   CodeSection* consts()            { return &_consts; }
 406 
 407   // present sections in order; return NULL at end; insts is #0, etc.
 408   CodeSection* code_section(int n) {
 409     // This makes the slightly questionable but portable assumption that
 410     // the various members (_insts, _stubs, etc.) are adjacent in the
 411     // layout of CodeBuffer.
 412     CodeSection* cs = &_insts + n;
 413     assert(cs->index() == n || !cs->is_allocated(), "sanity");
 414     return cs;
 415   }
 416   const CodeSection* code_section(int n) const {  // yucky const stuff
 417     return ((CodeBuffer*)this)->code_section(n);
 418   }
 419   static const char* code_section_name(int n);
 420   int section_index_of(address addr) const;
 421   bool contains(address addr) const {
 422     // handy for debugging
 423     return section_index_of(addr) > SECT_NONE;
 424   }
 425 
 426   // A stable mapping between 'locators' (small ints) and addresses.
 427   static int locator_pos(int locator)   { return locator >> sect_bits; }
 428   static int locator_sect(int locator)  { return locator &  sect_mask; }
 429   static int locator(int pos, int sect) { return (pos << sect_bits) | sect; }
 430   int        locator(address addr) const;
 431   address    locator_address(int locator) const;
 432 
 433   // Properties
 434   const char* name() const                  { return _name; }
 435   CodeBuffer* before_expand() const         { return _before_expand; }
 436   BufferBlob* blob() const                  { return _blob; }
 437   void    set_blob(BufferBlob* blob);
 438   void   free_blob();                       // Free the blob, if we own one.
 439 
 440   // Properties relative to the insts section:
 441   address code_begin() const            { return _insts.start(); }
 442   address code_end() const              { return _insts.end();   }
 443   void set_code_end(address end)        { _insts.set_end(end); }
 444   address code_limit() const            { return _insts.limit(); }
 445   address inst_mark() const             { return _insts.mark(); }
 446   void set_inst_mark()                  { _insts.set_mark(); }
 447   void clear_inst_mark()                { _insts.clear_mark(); }
 448 
 449   // is there anything in the buffer other than the current section?
 450   bool    is_pure() const               { return code_size() == total_code_size(); }
 451 
 452   // size in bytes of output so far in the insts sections
 453   csize_t code_size() const             { return _insts.size(); }
 454 
 455   // same as code_size(), except that it asserts there is no non-code here
 456   csize_t pure_code_size() const        { assert(is_pure(), "no non-code");
 457                                           return code_size(); }
 458   // capacity in bytes of the insts sections
 459   csize_t code_capacity() const         { return _insts.capacity(); }
 460 
 461   // number of bytes remaining in the insts section
 462   csize_t code_remaining() const        { return _insts.remaining(); }
 463 
 464   // is a given address in the insts section?  (2nd version is end-inclusive)
 465   bool code_contains(address pc) const  { return _insts.contains(pc); }
 466   bool code_contains2(address pc) const { return _insts.contains2(pc); }
 467 
 468   // allocated size of code in all sections, when aligned and concatenated
 469   // (this is the eventual state of the code in its final CodeBlob)
 470   csize_t total_code_size() const;
 471 
 472   // combined offset (relative to start of insts) of given address,
 473   // as eventually found in the final CodeBlob
 474   csize_t total_offset_of(address addr) const;
 475 
 476   // allocated size of all relocation data, including index, rounded up
 477   csize_t total_relocation_size() const;
 478 
 479   // allocated size of any and all recorded oops
 480   csize_t total_oop_size() const {
 481     OopRecorder* recorder = oop_recorder();
 482     return (recorder == NULL)? 0: recorder->oop_size();
 483   }
 484 
 485   // Configuration functions, called immediately after the CB is constructed.
 486   // The section sizes are subtracted from the original insts section.
 487   // Note:  Call them in reverse section order, because each steals from insts.
 488   void initialize_consts_size(csize_t size)            { initialize_section_size(&_consts,  size); }
 489   void initialize_stubs_size(csize_t size)             { initialize_section_size(&_stubs,   size); }
 490   // Override default oop recorder.
 491   void initialize_oop_recorder(OopRecorder* r);
 492 
 493   OopRecorder* oop_recorder() const   { return _oop_recorder; }
 494   CodeComments& comments()            { return _comments; }
 495 
 496   // Code generation
 497   void relocate(address at, RelocationHolder const& rspec, int format = 0) {
 498     _insts.relocate(at, rspec, format);
 499   }
 500   void relocate(address at,    relocInfo::relocType rtype, int format = 0) {
 501     _insts.relocate(at, rtype, format);
 502   }
 503 
 504   // Management of overflow storage for binding of Labels.
 505   GrowableArray<int>* create_patch_overflow();
 506 
 507   // NMethod generation
 508   void copy_code_and_locs_to(CodeBlob* blob) {
 509     assert(blob != NULL, "sane");
 510     copy_relocations_to(blob);
 511     copy_code_to(blob);
 512   }
 513   void copy_oops_to(nmethod* nm) {
 514     if (!oop_recorder()->is_unused()) {
 515       oop_recorder()->copy_to(nm);
 516     }
 517   }
 518 
 519   // Transform an address from the code in this code buffer to a specified code buffer
 520   address transform_address(const CodeBuffer &cb, address addr) const;
 521 
 522   void block_comment(intptr_t offset, const char * comment) PRODUCT_RETURN;
 523 
 524 #ifndef PRODUCT
 525  public:
 526   // Printing / Decoding
 527   // decodes from decode_begin() to code_end() and sets decode_begin to end
 528   void    decode();
 529   void    decode_all();         // decodes all the code
 530   void    skip_decode();        // sets decode_begin to code_end();
 531   void    print();
 532 #endif
 533 
 534 
 535   // The following header contains architecture-specific implementations
 536   #include "incls/_codeBuffer_pd.hpp.incl"
 537 };
 538 
 539 
 540 inline void CodeSection::freeze() {
 541   _outer->freeze_section(this);
 542 }
 543 
 544 inline bool CodeSection::maybe_expand_to_ensure_remaining(csize_t amount) {
 545   if (remaining() < amount) { _outer->expand(this, amount); return true; }
 546   return false;
 547 }