| /* |
| * 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. |
| * |
| */ |
| |
| // This file contains platform-independant assembler declarations. |
| |
| class CodeBuffer; |
| class MacroAssembler; |
| class AbstractAssembler; |
| class Label; |
| |
| /** |
| * Labels represent destinations for control transfer instructions. Such |
| * instructions can accept a Label as their target argument. A Label is |
| * bound to the current location in the code stream by calling the |
| * MacroAssembler's 'bind' method, which in turn calls the Label's 'bind' |
| * method. A Label may be referenced by an instruction before it's bound |
| * (i.e., 'forward referenced'). 'bind' stores the current code offset |
| * in the Label object. |
| * |
| * If an instruction references a bound Label, the offset field(s) within |
| * the instruction are immediately filled in based on the Label's code |
| * offset. If an instruction references an unbound label, that |
| * instruction is put on a list of instructions that must be patched |
| * (i.e., 'resolved') when the Label is bound. |
| * |
| * 'bind' will call the platform-specific 'patch_instruction' method to |
| * fill in the offset field(s) for each unresolved instruction (if there |
| * are any). 'patch_instruction' lives in one of the |
| * cpu/<arch>/vm/assembler_<arch>* files. |
| * |
| * Instead of using a linked list of unresolved instructions, a Label has |
| * an array of unresolved instruction code offsets. _patch_index |
| * contains the total number of forward references. If the Label's array |
| * overflows (i.e., _patch_index grows larger than the array size), a |
| * GrowableArray is allocated to hold the remaining offsets. (The cache |
| * size is 4 for now, which handles over 99.5% of the cases) |
| * |
| * Labels may only be used within a single CodeSection. If you need |
| * to create references between code sections, use explicit relocations. |
| */ |
| class Label VALUE_OBJ_CLASS_SPEC { |
| private: |
| enum { PatchCacheSize = 4 }; |
| |
| // _loc encodes both the binding state (via its sign) |
| // and the binding locator (via its value) of a label. |
| // |
| // _loc >= 0 bound label, loc() encodes the target (jump) position |
| // _loc == -1 unbound label |
| int _loc; |
| |
| // References to instructions that jump to this unresolved label. |
| // These instructions need to be patched when the label is bound |
| // using the platform-specific patchInstruction() method. |
| // |
| // To avoid having to allocate from the C-heap each time, we provide |
| // a local cache and use the overflow only if we exceed the local cache |
| int _patches[PatchCacheSize]; |
| int _patch_index; |
| GrowableArray<int>* _patch_overflow; |
| |
| Label(const Label&) { ShouldNotReachHere(); } |
| |
| public: |
| |
| /** |
| * After binding, be sure 'patch_instructions' is called later to link |
| */ |
| void bind_loc(int loc) { |
| assert(loc >= 0, "illegal locator"); |
| assert(_loc == -1, "already bound"); |
| _loc = loc; |
| } |
| void bind_loc(int pos, int sect); // = bind_loc(locator(pos, sect)) |
| |
| #ifndef PRODUCT |
| // Iterates over all unresolved instructions for printing |
| void print_instructions(MacroAssembler* masm) const; |
| #endif // PRODUCT |
| |
| /** |
| * Returns the position of the the Label in the code buffer |
| * The position is a 'locator', which encodes both offset and section. |
| */ |
| int loc() const { |
| assert(_loc >= 0, "unbound label"); |
| return _loc; |
| } |
| int loc_pos() const; // == locator_pos(loc()) |
| int loc_sect() const; // == locator_sect(loc()) |
| |
| bool is_bound() const { return _loc >= 0; } |
| bool is_unbound() const { return _loc == -1 && _patch_index > 0; } |
| bool is_unused() const { return _loc == -1 && _patch_index == 0; } |
| |
| /** |
| * Adds a reference to an unresolved displacement instruction to |
| * this unbound label |
| * |
| * @param cb the code buffer being patched |
| * @param branch_loc the locator of the branch instruction in the code buffer |
| */ |
| void add_patch_at(CodeBuffer* cb, int branch_loc); |
| |
| /** |
| * Iterate over the list of patches, resolving the instructions |
| * Call patch_instruction on each 'branch_loc' value |
| */ |
| void patch_instructions(MacroAssembler* masm); |
| |
| void init() { |
| _loc = -1; |
| _patch_index = 0; |
| _patch_overflow = NULL; |
| } |
| |
| Label() { |
| init(); |
| } |
| }; |
| |
| |
| // The Abstract Assembler: Pure assembler doing NO optimizations on the |
| // instruction level; i.e., what you write is what you get. |
| // The Assembler is generating code into a CodeBuffer. |
| class AbstractAssembler : public ResourceObj { |
| friend class Label; |
| |
| protected: |
| CodeSection* _code_section; // section within the code buffer |
| address _code_begin; // first byte of code buffer |
| address _code_limit; // first byte after code buffer |
| address _code_pos; // current code generation position |
| OopRecorder* _oop_recorder; // support for relocInfo::oop_type |
| |
| // Code emission & accessing |
| address addr_at(int pos) const { return _code_begin + pos; } |
| |
| // This routine is called with a label is used for an address. |
| // Labels and displacements truck in offsets, but target must return a PC. |
| address target(Label& L); // return _code_section->target(L) |
| |
| bool is8bit(int x) const { return -0x80 <= x && x < 0x80; } |
| bool isByte(int x) const { return 0 <= x && x < 0x100; } |
| bool isShiftCount(int x) const { return 0 <= x && x < 32; } |
| |
| void emit_byte(int x); // emit a single byte |
| void emit_word(int x); // emit a 16-bit word (not a wordSize word!) |
| void emit_long(jint x); // emit a 32-bit word (not a longSize word!) |
| void emit_address(address x); // emit an address (not a longSize word!) |
| |
| // Instruction boundaries (required when emitting relocatable values). |
| class InstructionMark: public StackObj { |
| private: |
| AbstractAssembler* _assm; |
| |
| public: |
| InstructionMark(AbstractAssembler* assm) : _assm(assm) { |
| assert(assm->inst_mark() == NULL, "overlapping instructions"); |
| _assm->set_inst_mark(); |
| } |
| ~InstructionMark() { |
| _assm->clear_inst_mark(); |
| } |
| }; |
| friend class InstructionMark; |
| #ifdef ASSERT |
| // Make it return true on platforms which need to verify |
| // instruction boundaries for some operations. |
| inline static bool pd_check_instruction_mark(); |
| #endif |
| |
| // Label functions |
| void print(Label& L); |
| |
| public: |
| |
| // Creation |
| AbstractAssembler(CodeBuffer* code); |
| |
| // save end pointer back to code buf. |
| void sync(); |
| |
| // ensure buf contains all code (call this before using/copying the code) |
| void flush(); |
| |
| // Accessors |
| CodeBuffer* code() const; // _code_section->outer() |
| CodeSection* code_section() const { return _code_section; } |
| int sect() const; // return _code_section->index() |
| address pc() const { return _code_pos; } |
| int offset() const { return _code_pos - _code_begin; } |
| int locator() const; // CodeBuffer::locator(offset(), sect()) |
| OopRecorder* oop_recorder() const { return _oop_recorder; } |
| void set_oop_recorder(OopRecorder* r) { _oop_recorder = r; } |
| |
| address inst_mark() const; |
| void set_inst_mark(); |
| void clear_inst_mark(); |
| |
| // Constants in code |
| void a_byte(int x); |
| void a_long(jint x); |
| void relocate(RelocationHolder const& rspec, int format = 0); |
| void relocate( relocInfo::relocType rtype, int format = 0) { |
| if (rtype != relocInfo::none) |
| relocate(Relocation::spec_simple(rtype), format); |
| } |
| |
| static int code_fill_byte(); // used to pad out odd-sized code buffers |
| |
| // Associate a comment with the current offset. It will be printed |
| // along with the disassembly when printing nmethods. Currently |
| // only supported in the instruction section of the code buffer. |
| void block_comment(const char* comment); |
| |
| // Label functions |
| void bind(Label& L); // binds an unbound label L to the current code position |
| |
| // Move to a different section in the same code buffer. |
| void set_code_section(CodeSection* cs); |
| |
| // Inform assembler when generating stub code and relocation info |
| address start_a_stub(int required_space); |
| void end_a_stub(); |
| // Ditto for constants. |
| address start_a_const(int required_space, int required_align = sizeof(double)); |
| void end_a_const(); |
| |
| // fp constants support |
| address double_constant(jdouble c) { |
| address ptr = start_a_const(sizeof(c), sizeof(c)); |
| if (ptr != NULL) { |
| *(jdouble*)ptr = c; |
| _code_pos = ptr + sizeof(c); |
| end_a_const(); |
| } |
| return ptr; |
| } |
| address float_constant(jfloat c) { |
| address ptr = start_a_const(sizeof(c), sizeof(c)); |
| if (ptr != NULL) { |
| *(jfloat*)ptr = c; |
| _code_pos = ptr + sizeof(c); |
| end_a_const(); |
| } |
| return ptr; |
| } |
| address address_constant(address c, RelocationHolder const& rspec) { |
| address ptr = start_a_const(sizeof(c), sizeof(c)); |
| if (ptr != NULL) { |
| relocate(rspec); |
| *(address*)ptr = c; |
| _code_pos = ptr + sizeof(c); |
| end_a_const(); |
| } |
| return ptr; |
| } |
| inline address address_constant(Label& L); |
| inline address address_table_constant(GrowableArray<Label*> label); |
| |
| // Bang stack to trigger StackOverflowError at a safe location |
| // implementation delegates to machine-specific bang_stack_with_offset |
| void generate_stack_overflow_check( int frame_size_in_bytes ); |
| virtual void bang_stack_with_offset(int offset) = 0; |
| |
| |
| /** |
| * A platform-dependent method to patch a jump instruction that refers |
| * to this label. |
| * |
| * @param branch the location of the instruction to patch |
| * @param masm the assembler which generated the branch |
| */ |
| void pd_patch_instruction(address branch, address target); |
| |
| #ifndef PRODUCT |
| /** |
| * Platform-dependent method of printing an instruction that needs to be |
| * patched. |
| * |
| * @param branch the instruction to be patched in the buffer. |
| */ |
| static void pd_print_patched_instruction(address branch); |
| #endif // PRODUCT |
| }; |
| |
| #include "incls/_assembler_pd.hpp.incl" |