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 /*

  * Copyright (c) 1997, 2014, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

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 #ifndef SHARE_VM_ASM_CODEBUFFER_HPP

 #define SHARE_VM_ASM_CODEBUFFER_HPP

 #include "code/oopRecorder.hpp"

 #include "code/relocInfo.hpp"

 class CodeStrings;

 class PhaseCFG;

 class Compile;

 class BufferBlob;

 class CodeBuffer;

 class Label;

 class CodeOffsets: public StackObj {

 public:

   enum Entries { Entry,

                  Verified_Entry,

                  Frame_Complete, // Offset in the code where the frame setup is (for forte stackwalks) is complete

                  OSR_Entry,

                  Dtrace_trap = OSR_Entry,  // dtrace probes can never have an OSR entry so reuse it

                  Exceptions,     // Offset where exception handler lives

                  Deopt,          // Offset where deopt handler lives

                  DeoptMH,        // Offset where MethodHandle deopt handler lives

                  UnwindHandler,  // Offset to default unwind handler

                  max_Entries };

   // special value to note codeBlobs where profile (forte) stack walking is

   // always dangerous and suspect.

   enum { frame_never_safe = -1 };

 private:

   int _values[max_Entries];

 public:

   CodeOffsets() {

     _values[Entry         ] = 0;

     _values[Verified_Entry] = 0;

     _values[Frame_Complete] = frame_never_safe;

     _values[OSR_Entry     ] = 0;

     _values[Exceptions    ] = -1;

     _values[Deopt         ] = -1;

     _values[DeoptMH       ] = -1;

     _values[UnwindHandler ] = -1;

   }

   int value(Entries e) { return _values[e]; }

   void set_value(Entries e, int val) { _values[e] = val; }

 };

 // This class represents a stream of code and associated relocations.

 // There are a few in each CodeBuffer.

 // They are filled concurrently, and concatenated at the end.

 class CodeSection VALUE_OBJ_CLASS_SPEC {

   friend class CodeBuffer;

  public:

   typedef int csize_t;  // code size type; would be size_t except for history

  private:

   address     _start;           // first byte of contents (instructions)

   address     _mark;            // user mark, usually an instruction beginning

   address     _end;             // current end address

   address     _limit;           // last possible (allocated) end address

   relocInfo*  _locs_start;      // first byte of relocation information

   relocInfo*  _locs_end;        // first byte after relocation information

   relocInfo*  _locs_limit;      // first byte after relocation information buf

   address     _locs_point;      // last relocated position (grows upward)

   bool        _locs_own;        // did I allocate the locs myself?

   bool        _frozen;          // no more expansion of this section

   char        _index;           // my section number (SECT_INST, etc.)

   CodeBuffer* _outer;           // enclosing CodeBuffer

   // (Note:  _locs_point used to be called _last_reloc_offset.)

   CodeSection() {

     _start         = NULL;

     _mark          = NULL;

     _end           = NULL;

     _limit         = NULL;

     _locs_start    = NULL;

     _locs_end      = NULL;

     _locs_limit    = NULL;

     _locs_point    = NULL;

     _locs_own      = false;

     _frozen        = false;

     debug_only(_index = (char)-1);

     debug_only(_outer = (CodeBuffer*)badAddress);

   }

   void initialize_outer(CodeBuffer* outer, int index) {

     _outer = outer;

     _index = index;

   }

   void initialize(address start, csize_t size = 0) {

     assert(_start == NULL, "only one init step, please");

     _start         = start;

     _mark          = NULL;

     _end           = start;

     _limit         = start + size;

     _locs_point    = start;

   }

   void initialize_locs(int locs_capacity);

   void expand_locs(int new_capacity);

   void initialize_locs_from(const CodeSection* source_cs);

   // helper for CodeBuffer::expand()

   void take_over_code_from(CodeSection* cs) {

     _start      = cs->_start;

     _mark       = cs->_mark;

     _end        = cs->_end;

     _limit      = cs->_limit;

     _locs_point = cs->_locs_point;

   }

  public:

   address     start() const         { return _start; }

   address     mark() const          { return _mark; }

   address     end() const           { return _end; }

   address     limit() const         { return _limit; }

   csize_t     size() const          { return (csize_t)(_end - _start); }

   csize_t     mark_off() const      { assert(_mark != NULL, "not an offset");

                                       return (csize_t)(_mark - _start); }

   csize_t     capacity() const      { return (csize_t)(_limit - _start); }

   csize_t     remaining() const     { return (csize_t)(_limit - _end); }

   relocInfo*  locs_start() const    { return _locs_start; }

   relocInfo*  locs_end() const      { return _locs_end; }

   int         locs_count() const    { return (int)(_locs_end - _locs_start); }

   relocInfo*  locs_limit() const    { return _locs_limit; }

   address     locs_point() const    { return _locs_point; }

   csize_t     locs_point_off() const{ return (csize_t)(_locs_point - _start); }

   csize_t     locs_capacity() const { return (csize_t)(_locs_limit - _locs_start); }

   csize_t     locs_remaining()const { return (csize_t)(_locs_limit - _locs_end); }

   int         index() const         { return _index; }

   bool        is_allocated() const  { return _start != NULL; }

   bool        is_empty() const      { return _start == _end; }

   bool        is_frozen() const     { return _frozen; }

   bool        has_locs() const      { return _locs_end != NULL; }

   CodeBuffer* outer() const         { return _outer; }

   // is a given address in this section?  (2nd version is end-inclusive)

   bool contains(address pc) const   { return pc >= _start && pc <  _end; }

   bool contains2(address pc) const  { return pc >= _start && pc <= _end; }

   bool allocates(address pc) const  { return pc >= _start && pc <  _limit; }

   bool allocates2(address pc) const { return pc >= _start && pc <= _limit; }

   void    set_end(address pc)       { assert(allocates2(pc), err_msg("not in CodeBuffer memory: " PTR_FORMAT " <= " PTR_FORMAT " <= " INTPTR_FORMAT, p2i(_start), p2i(pc), p2i(_limit))); _end = pc; }

   void    set_mark(address pc)      { assert(contains2(pc), "not in codeBuffer");

                                       _mark = pc; }

   void    set_mark_off(int offset)  { assert(contains2(offset+_start),"not in codeBuffer");

                                       _mark = offset + _start; }

   void    set_mark()                { _mark = _end; }

   void    clear_mark()              { _mark = NULL; }

   void    set_locs_end(relocInfo* p) {

     assert(p <= locs_limit(), "locs data fits in allocated buffer");

     _locs_end = p;

   }

   void    set_locs_point(address pc) {

     assert(pc >= locs_point(), "relocation addr may not decrease");

     assert(allocates2(pc),     "relocation addr must be in this section");

     _locs_point = pc;

   }

   // Code emission

   void emit_int8 ( int8_t  x)  { *((int8_t*)  end()) = x; set_end(end() + sizeof(int8_t)); }

   void emit_int16( int16_t x)  { *((int16_t*) end()) = x; set_end(end() + sizeof(int16_t)); }

   void emit_int32( int32_t x)  { *((int32_t*) end()) = x; set_end(end() + sizeof(int32_t)); }

   void emit_int64( int64_t x)  { *((int64_t*) end()) = x; set_end(end() + sizeof(int64_t)); }

   void emit_float( jfloat  x)  { *((jfloat*)  end()) = x; set_end(end() + sizeof(jfloat)); }

   void emit_double(jdouble x)  { *((jdouble*) end()) = x; set_end(end() + sizeof(jdouble)); }

   void emit_address(address x) { *((address*) end()) = x; set_end(end() + sizeof(address)); }

   // Share a scratch buffer for relocinfo.  (Hacky; saves a resource allocation.)

   void initialize_shared_locs(relocInfo* buf, int length);

   // Manage labels and their addresses.

   address target(Label& L, address branch_pc);

   // Emit a relocation.

   void relocate(address at, RelocationHolder const& rspec, int format = 0);

   void relocate(address at,    relocInfo::relocType rtype, int format = 0) {

     if (rtype != relocInfo::none)

       relocate(at, Relocation::spec_simple(rtype), format);

   }

   // alignment requirement for starting offset

   // Requirements are that the instruction area and the

   // stubs area must start on CodeEntryAlignment, and

   // the ctable on sizeof(jdouble)

   int alignment() const             { return MAX2((int)sizeof(jdouble), (int)CodeEntryAlignment); }

   // Slop between sections, used only when allocating temporary BufferBlob buffers.

   static csize_t end_slop()         { return MAX2((int)sizeof(jdouble), (int)CodeEntryAlignment); }

   csize_t align_at_start(csize_t off) const { return (csize_t) align_size_up(off, alignment()); }

   // Mark a section frozen.  Assign its remaining space to

   // the following section.  It will never expand after this point.

   inline void freeze();         //  { _outer->freeze_section(this); }

   // Ensure there's enough space left in the current section.

   // Return true if there was an expansion.

   bool maybe_expand_to_ensure_remaining(csize_t amount);

 #ifndef PRODUCT

   void decode();

   void dump();

   void print(const char* name);

 #endif //PRODUCT

 };

 class CodeString;

 class CodeStrings VALUE_OBJ_CLASS_SPEC {

 private:

 #ifndef PRODUCT

   CodeString* _strings;

 #endif

   CodeString* find(intptr_t offset) const;

   CodeString* find_last(intptr_t offset) const;

 public:

   CodeStrings() {

 #ifndef PRODUCT

     _strings = NULL;

 #endif

   }

   const char* add_string(const char * string) PRODUCT_RETURN_(return NULL;);

   void add_comment(intptr_t offset, const char * comment) PRODUCT_RETURN;

   void print_block_comment(outputStream* stream, intptr_t offset) const PRODUCT_RETURN;

   void assign(CodeStrings& other)  PRODUCT_RETURN;

   void free() PRODUCT_RETURN;

 };

 // A CodeBuffer describes a memory space into which assembly

 // code is generated.  This memory space usually occupies the

 // interior of a single BufferBlob, but in some cases it may be

 // an arbitrary span of memory, even outside the code cache.

 //

 // A code buffer comes in two variants:

 //

 // (1) A CodeBuffer referring to an already allocated piece of memory:

 //     This is used to direct 'static' code generation (e.g. for interpreter

 //     or stubroutine generation, etc.).  This code comes with NO relocation

 //     information.

 //

 // (2) A CodeBuffer referring to a piece of memory allocated when the

 //     CodeBuffer is allocated.  This is used for nmethod generation.

 //

 // The memory can be divided up into several parts called sections.

 // Each section independently accumulates code (or data) an relocations.

 // Sections can grow (at the expense of a reallocation of the BufferBlob

 // and recopying of all active sections).  When the buffered code is finally

 // written to an nmethod (or other CodeBlob), the contents (code, data,

 // and relocations) of the sections are padded to an alignment and concatenated.

 // Instructions and data in one section can contain relocatable references to

 // addresses in a sibling section.

 class CodeBuffer: public StackObj {

   friend class CodeSection;

  private:

   // CodeBuffers must be allocated on the stack except for a single

   // special case during expansion which is handled internally.  This

   // is done to guarantee proper cleanup of resources.

   void* operator new(size_t size) throw() { return ResourceObj::operator new(size); }

   void  operator delete(void* p)          { ShouldNotCallThis(); }

  public:

   typedef int csize_t;  // code size type; would be size_t except for history

   enum {

     // Here is the list of all possible sections.  The order reflects

     // the final layout.

     SECT_FIRST = 0,

     SECT_CONSTS = SECT_FIRST, // Non-instruction data:  Floats, jump tables, etc.

     SECT_INSTS,               // Executable instructions.

     SECT_STUBS,               // Outbound trampolines for supporting call sites.

     SECT_LIMIT, SECT_NONE = -1

   };

  private:

   enum {

     sect_bits = 2,      // assert (SECT_LIMIT <= (1<<sect_bits))

     sect_mask = (1<<sect_bits)-1

   };

   const char*  _name;

   CodeSection  _consts;             // constants, jump tables

   CodeSection  _insts;              // instructions (the main section)

   CodeSection  _stubs;              // stubs (call site support), deopt, exception handling

   CodeBuffer*  _before_expand;  // dead buffer, from before the last expansion

   BufferBlob*  _blob;           // optional buffer in CodeCache for generated code

   address      _total_start;    // first address of combined memory buffer

   csize_t      _total_size;     // size in bytes of combined memory buffer

   OopRecorder* _oop_recorder;

   CodeStrings  _strings;

   OopRecorder  _default_oop_recorder;  // override with initialize_oop_recorder

   Arena*       _overflow_arena;

   address      _decode_begin;   // start address for decode

   address      decode_begin();

   void initialize_misc(const char * name) {

     // all pointers other than code_start/end and those inside the sections

     assert(name != NULL, "must have a name");

     _name            = name;

     _before_expand   = NULL;

     _blob            = NULL;

     _oop_recorder    = NULL;

     _decode_begin    = NULL;

     _overflow_arena  = NULL;

   }

   void initialize(address code_start, csize_t code_size) {

     _consts.initialize_outer(this,  SECT_CONSTS);

     _insts.initialize_outer(this,   SECT_INSTS);

     _stubs.initialize_outer(this,   SECT_STUBS);

     _total_start = code_start;

     _total_size  = code_size;

     // Initialize the main section:

     _insts.initialize(code_start, code_size);

     assert(!_stubs.is_allocated(),  "no garbage here");

     assert(!_consts.is_allocated(), "no garbage here");

     _oop_recorder = &_default_oop_recorder;

   }

   void initialize_section_size(CodeSection* cs, csize_t size);

   void freeze_section(CodeSection* cs);

   // helper for CodeBuffer::expand()

   void take_over_code_from(CodeBuffer* cs);

   // ensure sections are disjoint, ordered, and contained in the blob

   void verify_section_allocation();

   // copies combined relocations to the blob, returns bytes copied

   // (if target is null, it is a dry run only, just for sizing)

   csize_t copy_relocations_to(CodeBlob* blob) const;

   // copies combined code to the blob (assumes relocs are already in there)

   void copy_code_to(CodeBlob* blob);

   // moves code sections to new buffer (assumes relocs are already in there)

   void relocate_code_to(CodeBuffer* cb) const;

   // set up a model of the final layout of my contents

   void compute_final_layout(CodeBuffer* dest) const;

   // Expand the given section so at least 'amount' is remaining.

   // Creates a new, larger BufferBlob, and rewrites the code & relocs.

   void expand(CodeSection* which_cs, csize_t amount);

   // Helper for expand.

   csize_t figure_expanded_capacities(CodeSection* which_cs, csize_t amount, csize_t* new_capacity);

  public:

   // (1) code buffer referring to pre-allocated instruction memory

   CodeBuffer(address code_start, csize_t code_size) {

     assert(code_start != NULL, "sanity");

     initialize_misc("static buffer");

     initialize(code_start, code_size);

     verify_section_allocation();

   }

   // (2) CodeBuffer referring to pre-allocated CodeBlob.

   CodeBuffer(CodeBlob* blob);

   // (3) code buffer allocating codeBlob memory for code & relocation

   // info but with lazy initialization.  The name must be something

   // informative.

   CodeBuffer(const char* name) {

     initialize_misc(name);

   }

   // (4) code buffer allocating codeBlob memory for code & relocation

   // info.  The name must be something informative and code_size must

   // include both code and stubs sizes.

   CodeBuffer(const char* name, csize_t code_size, csize_t locs_size) {

     initialize_misc(name);

     initialize(code_size, locs_size);

   }

   ~CodeBuffer();

   // Initialize a CodeBuffer constructed using constructor 3.  Using

   // constructor 4 is equivalent to calling constructor 3 and then

   // calling this method.  It's been factored out for convenience of

   // construction.

   void initialize(csize_t code_size, csize_t locs_size);

   CodeSection* consts()            { return &_consts; }

   CodeSection* insts()             { return &_insts; }

   CodeSection* stubs()             { return &_stubs; }

   // present sections in order; return NULL at end; consts is #0, etc.

   CodeSection* code_section(int n) {

     // This makes the slightly questionable but portable assumption

     // that the various members (_consts, _insts, _stubs, etc.) are

     // adjacent in the layout of CodeBuffer.

     CodeSection* cs = &_consts + n;

     assert(cs->index() == n || !cs->is_allocated(), "sanity");

     return cs;

   }

   const CodeSection* code_section(int n) const {  // yucky const stuff

     return ((CodeBuffer*)this)->code_section(n);

   }

   static const char* code_section_name(int n);

   int section_index_of(address addr) const;

   bool contains(address addr) const {

     // handy for debugging

     return section_index_of(addr) > SECT_NONE;

   }

   // A stable mapping between 'locators' (small ints) and addresses.

   static int locator_pos(int locator)   { return locator >> sect_bits; }

   static int locator_sect(int locator)  { return locator &  sect_mask; }

   static int locator(int pos, int sect) { return (pos << sect_bits) | sect; }

   int        locator(address addr) const;

   address    locator_address(int locator) const;

   // Heuristic for pre-packing the taken/not-taken bit of a predicted branch.

   bool is_backward_branch(Label& L);

   // Properties

   const char* name() const                  { return _name; }

   CodeBuffer* before_expand() const         { return _before_expand; }

   BufferBlob* blob() const                  { return _blob; }

   void    set_blob(BufferBlob* blob);

   void   free_blob();                       // Free the blob, if we own one.

   // Properties relative to the insts section:

   address       insts_begin() const      { return _insts.start();      }

   address       insts_end() const        { return _insts.end();        }

   void      set_insts_end(address end)   {        _insts.set_end(end); }

   address       insts_limit() const      { return _insts.limit();      }

   address       insts_mark() const       { return _insts.mark();       }

   void      set_insts_mark()             {        _insts.set_mark();   }

   void    clear_insts_mark()             {        _insts.clear_mark(); }

   // is there anything in the buffer other than the current section?

   bool    is_pure() const                { return insts_size() == total_content_size(); }

   // size in bytes of output so far in the insts sections

   csize_t insts_size() const             { return _insts.size(); }

   // same as insts_size(), except that it asserts there is no non-code here

   csize_t pure_insts_size() const        { assert(is_pure(), "no non-code");

                                            return insts_size(); }

   // capacity in bytes of the insts sections

   csize_t insts_capacity() const         { return _insts.capacity(); }

   // number of bytes remaining in the insts section

   csize_t insts_remaining() const        { return _insts.remaining(); }

   // is a given address in the insts section?  (2nd version is end-inclusive)

   bool insts_contains(address pc) const  { return _insts.contains(pc); }

   bool insts_contains2(address pc) const { return _insts.contains2(pc); }

   // Record any extra oops required to keep embedded metadata alive

   void finalize_oop_references(methodHandle method);

   // Allocated size in all sections, when aligned and concatenated

   // (this is the eventual state of the content in its final

   // CodeBlob).

   csize_t total_content_size() const;

   // Combined offset (relative to start of first section) of given

   // section, as eventually found in the final CodeBlob.

   csize_t total_offset_of(CodeSection* cs) const;

   // allocated size of all relocation data, including index, rounded up

   csize_t total_relocation_size() const;

   // allocated size of any and all recorded oops

   csize_t total_oop_size() const {

     OopRecorder* recorder = oop_recorder();

     return (recorder == NULL)? 0: recorder->oop_size();

   }

   // allocated size of any and all recorded metadata

   csize_t total_metadata_size() const {

     OopRecorder* recorder = oop_recorder();

     return (recorder == NULL)? 0: recorder->metadata_size();

   }

   // Configuration functions, called immediately after the CB is constructed.

   // The section sizes are subtracted from the original insts section.

   // Note:  Call them in reverse section order, because each steals from insts.

   void initialize_consts_size(csize_t size)            { initialize_section_size(&_consts,  size); }

   void initialize_stubs_size(csize_t size)             { initialize_section_size(&_stubs,   size); }

   // Override default oop recorder.

   void initialize_oop_recorder(OopRecorder* r);

   OopRecorder* oop_recorder() const   { return _oop_recorder; }

   CodeStrings& strings()              { return _strings; }

   // Code generation

   void relocate(address at, RelocationHolder const& rspec, int format = 0) {

     _insts.relocate(at, rspec, format);

   }

   void relocate(address at,    relocInfo::relocType rtype, int format = 0) {

     _insts.relocate(at, rtype, format);

   }

   // Management of overflow storage for binding of Labels.

   GrowableArray<int>* create_patch_overflow();

   // NMethod generation

   void copy_code_and_locs_to(CodeBlob* blob) {

     assert(blob != NULL, "sane");

     copy_relocations_to(blob);

     copy_code_to(blob);

   }

   void copy_values_to(nmethod* nm) {

     if (!oop_recorder()->is_unused()) {

       oop_recorder()->copy_values_to(nm);

     }

   }

   // Transform an address from the code in this code buffer to a specified code buffer

   address transform_address(const CodeBuffer &cb, address addr) const;

   void block_comment(intptr_t offset, const char * comment) PRODUCT_RETURN;

   const char* code_string(const char* str) PRODUCT_RETURN_(return NULL;);

   // Log a little info about section usage in the CodeBuffer

   void log_section_sizes(const char* name);

 #ifndef PRODUCT

  public:

   // Printing / Decoding

   // decodes from decode_begin() to code_end() and sets decode_begin to end

   void    decode();

   void    decode_all();         // decodes all the code

   void    skip_decode();        // sets decode_begin to code_end();

   void    print();

 #endif

   // The following header contains architecture-specific implementations

 #ifdef TARGET_ARCH_x86

 # include "codeBuffer_x86.hpp"

 #endif

 #ifdef TARGET_ARCH_sparc

 # include "codeBuffer_sparc.hpp"

 #endif

 #ifdef TARGET_ARCH_zero

 # include "codeBuffer_zero.hpp"

 #endif

 #ifdef TARGET_ARCH_arm

 # include "codeBuffer_arm.hpp"

 #endif

 #ifdef TARGET_ARCH_ppc

 # include "codeBuffer_ppc.hpp"

 #endif

 };

 inline void CodeSection::freeze() {

   _outer->freeze_section(this);

 }

 inline bool CodeSection::maybe_expand_to_ensure_remaining(csize_t amount) {

   if (remaining() < amount) { _outer->expand(this, amount); return true; }

   return false;

 }

 #endif // SHARE_VM_ASM_CODEBUFFER_HPP