duke@435: /*
jrose@1100:  * Copyright 1997-2009 Sun Microsystems, Inc.  All Rights Reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
duke@435:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435:  * CA 95054 USA or visit www.sun.com if you need additional information or
duke@435:  * have any questions.
duke@435:  *
duke@435:  */
duke@435: 
twisti@1040: // This file contains platform-independent assembler declarations.
duke@435: 
duke@435: class CodeBuffer;
duke@435: class MacroAssembler;
duke@435: class AbstractAssembler;
duke@435: class Label;
duke@435: 
duke@435: /**
duke@435:  * Labels represent destinations for control transfer instructions.  Such
duke@435:  * instructions can accept a Label as their target argument.  A Label is
duke@435:  * bound to the current location in the code stream by calling the
duke@435:  * MacroAssembler's 'bind' method, which in turn calls the Label's 'bind'
duke@435:  * method.  A Label may be referenced by an instruction before it's bound
duke@435:  * (i.e., 'forward referenced').  'bind' stores the current code offset
duke@435:  * in the Label object.
duke@435:  *
duke@435:  * If an instruction references a bound Label, the offset field(s) within
duke@435:  * the instruction are immediately filled in based on the Label's code
duke@435:  * offset.  If an instruction references an unbound label, that
duke@435:  * instruction is put on a list of instructions that must be patched
duke@435:  * (i.e., 'resolved') when the Label is bound.
duke@435:  *
duke@435:  * 'bind' will call the platform-specific 'patch_instruction' method to
duke@435:  * fill in the offset field(s) for each unresolved instruction (if there
duke@435:  * are any).  'patch_instruction' lives in one of the
duke@435:  * cpu/<arch>/vm/assembler_<arch>* files.
duke@435:  *
duke@435:  * Instead of using a linked list of unresolved instructions, a Label has
duke@435:  * an array of unresolved instruction code offsets.  _patch_index
duke@435:  * contains the total number of forward references.  If the Label's array
duke@435:  * overflows (i.e., _patch_index grows larger than the array size), a
duke@435:  * GrowableArray is allocated to hold the remaining offsets.  (The cache
duke@435:  * size is 4 for now, which handles over 99.5% of the cases)
duke@435:  *
duke@435:  * Labels may only be used within a single CodeSection.  If you need
duke@435:  * to create references between code sections, use explicit relocations.
duke@435:  */
duke@435: class Label VALUE_OBJ_CLASS_SPEC {
duke@435:  private:
duke@435:   enum { PatchCacheSize = 4 };
duke@435: 
duke@435:   // _loc encodes both the binding state (via its sign)
duke@435:   // and the binding locator (via its value) of a label.
duke@435:   //
duke@435:   // _loc >= 0   bound label, loc() encodes the target (jump) position
duke@435:   // _loc == -1  unbound label
duke@435:   int _loc;
duke@435: 
duke@435:   // References to instructions that jump to this unresolved label.
duke@435:   // These instructions need to be patched when the label is bound
duke@435:   // using the platform-specific patchInstruction() method.
duke@435:   //
duke@435:   // To avoid having to allocate from the C-heap each time, we provide
duke@435:   // a local cache and use the overflow only if we exceed the local cache
duke@435:   int _patches[PatchCacheSize];
duke@435:   int _patch_index;
duke@435:   GrowableArray<int>* _patch_overflow;
duke@435: 
duke@435:   Label(const Label&) { ShouldNotReachHere(); }
duke@435: 
duke@435:  public:
duke@435: 
duke@435:   /**
duke@435:    * After binding, be sure 'patch_instructions' is called later to link
duke@435:    */
duke@435:   void bind_loc(int loc) {
duke@435:     assert(loc >= 0, "illegal locator");
duke@435:     assert(_loc == -1, "already bound");
duke@435:     _loc = loc;
duke@435:   }
duke@435:   void bind_loc(int pos, int sect);  // = bind_loc(locator(pos, sect))
duke@435: 
duke@435: #ifndef PRODUCT
duke@435:   // Iterates over all unresolved instructions for printing
duke@435:   void print_instructions(MacroAssembler* masm) const;
duke@435: #endif // PRODUCT
duke@435: 
duke@435:   /**
duke@435:    * Returns the position of the the Label in the code buffer
duke@435:    * The position is a 'locator', which encodes both offset and section.
duke@435:    */
duke@435:   int loc() const {
duke@435:     assert(_loc >= 0, "unbound label");
duke@435:     return _loc;
duke@435:   }
duke@435:   int loc_pos() const;   // == locator_pos(loc())
duke@435:   int loc_sect() const;  // == locator_sect(loc())
duke@435: 
duke@435:   bool is_bound() const    { return _loc >=  0; }
duke@435:   bool is_unbound() const  { return _loc == -1 && _patch_index > 0; }
duke@435:   bool is_unused() const   { return _loc == -1 && _patch_index == 0; }
duke@435: 
duke@435:   /**
duke@435:    * Adds a reference to an unresolved displacement instruction to
duke@435:    * this unbound label
duke@435:    *
duke@435:    * @param cb         the code buffer being patched
duke@435:    * @param branch_loc the locator of the branch instruction in the code buffer
duke@435:    */
duke@435:   void add_patch_at(CodeBuffer* cb, int branch_loc);
duke@435: 
duke@435:   /**
duke@435:    * Iterate over the list of patches, resolving the instructions
duke@435:    * Call patch_instruction on each 'branch_loc' value
duke@435:    */
duke@435:   void patch_instructions(MacroAssembler* masm);
duke@435: 
duke@435:   void init() {
duke@435:     _loc = -1;
duke@435:     _patch_index = 0;
duke@435:     _patch_overflow = NULL;
duke@435:   }
duke@435: 
duke@435:   Label() {
duke@435:     init();
duke@435:   }
duke@435: };
duke@435: 
jrose@1057: // A union type for code which has to assemble both constant and
jrose@1057: // non-constant operands, when the distinction cannot be made
jrose@1057: // statically.
jrose@1100: class RegisterOrConstant VALUE_OBJ_CLASS_SPEC {
jrose@1057:  private:
jrose@1057:   Register _r;
jrose@1057:   intptr_t _c;
jrose@1057: 
jrose@1057:  public:
jrose@1100:   RegisterOrConstant(): _r(noreg), _c(0) {}
jrose@1100:   RegisterOrConstant(Register r): _r(r), _c(0) {}
jrose@1100:   RegisterOrConstant(intptr_t c): _r(noreg), _c(c) {}
jrose@1057: 
jrose@1057:   Register as_register() const { assert(is_register(),""); return _r; }
jrose@1057:   intptr_t as_constant() const { assert(is_constant(),""); return _c; }
jrose@1057: 
jrose@1057:   Register register_or_noreg() const { return _r; }
jrose@1057:   intptr_t constant_or_zero() const  { return _c; }
jrose@1057: 
jrose@1057:   bool is_register() const { return _r != noreg; }
jrose@1057:   bool is_constant() const { return _r == noreg; }
jrose@1057: };
duke@435: 
duke@435: // The Abstract Assembler: Pure assembler doing NO optimizations on the
duke@435: // instruction level; i.e., what you write is what you get.
duke@435: // The Assembler is generating code into a CodeBuffer.
duke@435: class AbstractAssembler : public ResourceObj  {
duke@435:   friend class Label;
duke@435: 
duke@435:  protected:
duke@435:   CodeSection* _code_section;          // section within the code buffer
duke@435:   address      _code_begin;            // first byte of code buffer
duke@435:   address      _code_limit;            // first byte after code buffer
duke@435:   address      _code_pos;              // current code generation position
duke@435:   OopRecorder* _oop_recorder;          // support for relocInfo::oop_type
duke@435: 
duke@435:   // Code emission & accessing
duke@435:   address addr_at(int pos) const       { return _code_begin + pos; }
duke@435: 
duke@435:   // This routine is called with a label is used for an address.
duke@435:   // Labels and displacements truck in offsets, but target must return a PC.
duke@435:   address target(Label& L);            // return _code_section->target(L)
duke@435: 
duke@435:   bool is8bit(int x) const             { return -0x80 <= x && x < 0x80; }
duke@435:   bool isByte(int x) const             { return 0 <= x && x < 0x100; }
duke@435:   bool isShiftCount(int x) const       { return 0 <= x && x < 32; }
duke@435: 
duke@435:   void emit_byte(int x);  // emit a single byte
duke@435:   void emit_word(int x);  // emit a 16-bit word (not a wordSize word!)
duke@435:   void emit_long(jint x); // emit a 32-bit word (not a longSize word!)
duke@435:   void emit_address(address x); // emit an address (not a longSize word!)
duke@435: 
duke@435:   // Instruction boundaries (required when emitting relocatable values).
duke@435:   class InstructionMark: public StackObj {
duke@435:    private:
duke@435:     AbstractAssembler* _assm;
duke@435: 
duke@435:    public:
duke@435:     InstructionMark(AbstractAssembler* assm) : _assm(assm) {
duke@435:       assert(assm->inst_mark() == NULL, "overlapping instructions");
duke@435:       _assm->set_inst_mark();
duke@435:     }
duke@435:     ~InstructionMark() {
duke@435:       _assm->clear_inst_mark();
duke@435:     }
duke@435:   };
duke@435:   friend class InstructionMark;
duke@435:   #ifdef ASSERT
duke@435:   // Make it return true on platforms which need to verify
duke@435:   // instruction boundaries for some operations.
duke@435:   inline static bool pd_check_instruction_mark();
duke@435:   #endif
duke@435: 
duke@435:   // Label functions
duke@435:   void print(Label& L);
duke@435: 
duke@435:  public:
duke@435: 
duke@435:   // Creation
duke@435:   AbstractAssembler(CodeBuffer* code);
duke@435: 
duke@435:   // save end pointer back to code buf.
duke@435:   void sync();
duke@435: 
duke@435:   // ensure buf contains all code (call this before using/copying the code)
duke@435:   void flush();
duke@435: 
duke@435:   // Accessors
duke@435:   CodeBuffer*   code() const;          // _code_section->outer()
duke@435:   CodeSection*  code_section() const   { return _code_section; }
duke@435:   int           sect() const;          // return _code_section->index()
duke@435:   address       pc() const             { return _code_pos; }
duke@435:   int           offset() const         { return _code_pos - _code_begin; }
duke@435:   int           locator() const;       // CodeBuffer::locator(offset(), sect())
duke@435:   OopRecorder*  oop_recorder() const   { return _oop_recorder; }
duke@435:   void      set_oop_recorder(OopRecorder* r) { _oop_recorder = r; }
duke@435: 
duke@435:   address  inst_mark() const;
duke@435:   void set_inst_mark();
duke@435:   void clear_inst_mark();
duke@435: 
duke@435:   // Constants in code
duke@435:   void a_byte(int x);
duke@435:   void a_long(jint x);
duke@435:   void relocate(RelocationHolder const& rspec, int format = 0);
duke@435:   void relocate(   relocInfo::relocType rtype, int format = 0) {
duke@435:     if (rtype != relocInfo::none)
duke@435:       relocate(Relocation::spec_simple(rtype), format);
duke@435:   }
duke@435: 
duke@435:   static int code_fill_byte();         // used to pad out odd-sized code buffers
duke@435: 
duke@435:   // Associate a comment with the current offset.  It will be printed
duke@435:   // along with the disassembly when printing nmethods.  Currently
duke@435:   // only supported in the instruction section of the code buffer.
duke@435:   void block_comment(const char* comment);
duke@435: 
duke@435:   // Label functions
duke@435:   void bind(Label& L); // binds an unbound label L to the current code position
duke@435: 
duke@435:   // Move to a different section in the same code buffer.
duke@435:   void set_code_section(CodeSection* cs);
duke@435: 
duke@435:   // Inform assembler when generating stub code and relocation info
duke@435:   address    start_a_stub(int required_space);
duke@435:   void       end_a_stub();
duke@435:   // Ditto for constants.
duke@435:   address    start_a_const(int required_space, int required_align = sizeof(double));
duke@435:   void       end_a_const();
duke@435: 
duke@435:   // fp constants support
duke@435:   address double_constant(jdouble c) {
duke@435:     address ptr = start_a_const(sizeof(c), sizeof(c));
duke@435:     if (ptr != NULL) {
duke@435:       *(jdouble*)ptr = c;
duke@435:       _code_pos = ptr + sizeof(c);
duke@435:       end_a_const();
duke@435:     }
duke@435:     return ptr;
duke@435:   }
duke@435:   address float_constant(jfloat c) {
duke@435:     address ptr = start_a_const(sizeof(c), sizeof(c));
duke@435:     if (ptr != NULL) {
duke@435:       *(jfloat*)ptr = c;
duke@435:       _code_pos = ptr + sizeof(c);
duke@435:       end_a_const();
duke@435:     }
duke@435:     return ptr;
duke@435:   }
duke@435:   address address_constant(address c, RelocationHolder const& rspec) {
duke@435:     address ptr = start_a_const(sizeof(c), sizeof(c));
duke@435:     if (ptr != NULL) {
duke@435:       relocate(rspec);
duke@435:       *(address*)ptr = c;
duke@435:       _code_pos = ptr + sizeof(c);
duke@435:       end_a_const();
duke@435:     }
duke@435:     return ptr;
duke@435:   }
duke@435:   inline address address_constant(Label& L);
duke@435:   inline address address_table_constant(GrowableArray<Label*> label);
duke@435: 
jrose@1057:   // Bootstrapping aid to cope with delayed determination of constants.
jrose@1057:   // Returns a static address which will eventually contain the constant.
jrose@1057:   // The value zero (NULL) stands instead of a constant which is still uncomputed.
jrose@1057:   // Thus, the eventual value of the constant must not be zero.
jrose@1057:   // This is fine, since this is designed for embedding object field
jrose@1057:   // offsets in code which must be generated before the object class is loaded.
jrose@1057:   // Field offsets are never zero, since an object's header (mark word)
jrose@1057:   // is located at offset zero.
jrose@1100:   RegisterOrConstant delayed_value(int(*value_fn)(), Register tmp, int offset = 0) {
jrose@1100:     return delayed_value_impl(delayed_value_addr(value_fn), tmp, offset);
jrose@1057:   }
jrose@1100:   RegisterOrConstant delayed_value(address(*value_fn)(), Register tmp, int offset = 0) {
jrose@1100:     return delayed_value_impl(delayed_value_addr(value_fn), tmp, offset);
jrose@1057:   }
jrose@1100:   virtual RegisterOrConstant delayed_value_impl(intptr_t* delayed_value_addr, Register tmp, int offset) = 0;
jrose@1057:   // Last overloading is platform-dependent; look in assembler_<arch>.cpp.
jrose@1057:   static intptr_t* delayed_value_addr(int(*constant_fn)());
jrose@1057:   static intptr_t* delayed_value_addr(address(*constant_fn)());
jrose@1057:   static void update_delayed_values();
jrose@1057: 
duke@435:   // Bang stack to trigger StackOverflowError at a safe location
duke@435:   // implementation delegates to machine-specific bang_stack_with_offset
duke@435:   void generate_stack_overflow_check( int frame_size_in_bytes );
duke@435:   virtual void bang_stack_with_offset(int offset) = 0;
duke@435: 
duke@435: 
duke@435:   /**
duke@435:    * A platform-dependent method to patch a jump instruction that refers
duke@435:    * to this label.
duke@435:    *
duke@435:    * @param branch the location of the instruction to patch
duke@435:    * @param masm the assembler which generated the branch
duke@435:    */
duke@435:   void pd_patch_instruction(address branch, address target);
duke@435: 
duke@435: #ifndef PRODUCT
duke@435:   /**
duke@435:    * Platform-dependent method of printing an instruction that needs to be
duke@435:    * patched.
duke@435:    *
duke@435:    * @param branch the instruction to be patched in the buffer.
duke@435:    */
duke@435:   static void pd_print_patched_instruction(address branch);
duke@435: #endif // PRODUCT
duke@435: };
duke@435: 
duke@435: #include "incls/_assembler_pd.hpp.incl"