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hotspot/src/share/vm/asm/codeBuffer.hpp

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+/*
+ * Copyright 1997-2006 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  CodeComments;
+class  AbstractAssembler;
+class  MacroAssembler;
+class  PhaseCFG;
+class  Compile;
+class  BufferBlob;
+class  CodeBuffer;
+
+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,
+                 Exceptions,     // Offset where exception handler lives
+                 Deopt,          // Offset where deopt handler lives
+                 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;
+  }
+
+  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 = -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),""); _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;
+  }
+
+  // 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 CodeComment;
+class CodeComments VALUE_OBJ_CLASS_SPEC {
+private:
+#ifndef PRODUCT
+  CodeComment* _comments;
+#endif
+
+public:
+  CodeComments() {
+#ifndef PRODUCT
+    _comments = NULL;
+#endif
+  }
+
+  void add_comment(intptr_t offset, const char * comment) PRODUCT_RETURN;
+  void print_block_comment(outputStream* stream, intptr_t offset)  PRODUCT_RETURN;
+  void assign(CodeComments& 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) { return ResourceObj::operator new(size); }
+  void  operator delete(void* p)  {        ResourceObj::operator delete(p); }
+
+ public:
+  typedef int csize_t;  // code size type; would be size_t except for history
+  enum {
+    // Here is the list of all possible sections, in order of ascending address.
+    SECT_INSTS,               // Executable instructions.
+    SECT_STUBS,               // Outbound trampolines for supporting call sites.
+    SECT_CONSTS,              // Non-instruction data:  Floats, jump tables, etc.
+    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  _insts;              // instructions (the main section)
+  CodeSection  _stubs;              // stubs (call site support), deopt, exception handling
+  CodeSection  _consts;             // constants, jump tables
+
+  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;
+  CodeComments _comments;
+  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) {
+    _insts.initialize_outer(this,   SECT_INSTS);
+    _stubs.initialize_outer(this,   SECT_STUBS);
+    _consts.initialize_outer(this,  SECT_CONSTS);
+    _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);
+
+#ifdef ASSERT
+  // ensure sections are disjoint, ordered, and contained in the blob
+  bool verify_section_allocation();
+#endif
+
+  // 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);
+
+  // (2) 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);
+  }
+
+
+  // (3) 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 2.  Using
+  // constructor 3 is equivalent to calling constructor 2 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* insts()             { return &_insts; }
+  CodeSection* stubs()             { return &_stubs; }
+  CodeSection* consts()            { return &_consts; }
+
+  // present sections in order; return NULL at end; insts is #0, etc.
+  CodeSection* code_section(int n) {
+    // This makes the slightly questionable but portable assumption that
+    // the various members (_insts, _stubs, etc.) are adjacent in the
+    // layout of CodeBuffer.
+    CodeSection* cs = &_insts + 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;
+
+  // 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 code_begin() const            { return _insts.start(); }
+  address code_end() const              { return _insts.end();   }
+  void set_code_end(address end)        { _insts.set_end(end); }
+  address code_limit() const            { return _insts.limit(); }
+  address inst_mark() const             { return _insts.mark(); }
+  void set_inst_mark()                  { _insts.set_mark(); }
+  void clear_inst_mark()                { _insts.clear_mark(); }
+
+  // is there anything in the buffer other than the current section?
+  bool    is_pure() const               { return code_size() == total_code_size(); }
+
+  // size in bytes of output so far in the insts sections
+  csize_t code_size() const             { return _insts.size(); }
+
+  // same as code_size(), except that it asserts there is no non-code here
+  csize_t pure_code_size() const        { assert(is_pure(), "no non-code");
+                                          return code_size(); }
+  // capacity in bytes of the insts sections
+  csize_t code_capacity() const         { return _insts.capacity(); }
+
+  // number of bytes remaining in the insts section
+  csize_t code_remaining() const        { return _insts.remaining(); }
+
+  // is a given address in the insts section?  (2nd version is end-inclusive)
+  bool code_contains(address pc) const  { return _insts.contains(pc); }
+  bool code_contains2(address pc) const { return _insts.contains2(pc); }
+
+  // allocated size of code in all sections, when aligned and concatenated
+  // (this is the eventual state of the code in its final CodeBlob)
+  csize_t total_code_size() const;
+
+  // combined offset (relative to start of insts) of given address,
+  // as eventually found in the final CodeBlob
+  csize_t total_offset_of(address addr) 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();
+  }
+
+  // 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; }
+  CodeComments& comments()            { return _comments; }
+
+  // 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_oops_to(CodeBlob* blob) {
+    if (!oop_recorder()->is_unused()) {
+      oop_recorder()->copy_to(blob);
+    }
+  }
+
+  // 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;
+
+#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
+  #include "incls/_codeBuffer_pd.hpp.incl"
+};
+
+
+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;
+}