assembler.hpp revision 605:98cb887364d3
1227825Stheraven/* 2227825Stheraven * Copyright 1997-2006 Sun Microsystems, Inc. All Rights Reserved. 3227825Stheraven * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4227825Stheraven * 5227825Stheraven * This code is free software; you can redistribute it and/or modify it 6227825Stheraven * under the terms of the GNU General Public License version 2 only, as 7227825Stheraven * published by the Free Software Foundation. 8227825Stheraven * 9227825Stheraven * This code is distributed in the hope that it will be useful, but WITHOUT 10227825Stheraven * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11227825Stheraven * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12227825Stheraven * version 2 for more details (a copy is included in the LICENSE file that 13227825Stheraven * accompanied this code). 14227825Stheraven * 15227825Stheraven * You should have received a copy of the GNU General Public License version 16227825Stheraven * 2 along with this work; if not, write to the Free Software Foundation, 17227825Stheraven * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18227825Stheraven * 19227825Stheraven * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 20227825Stheraven * CA 95054 USA or visit www.sun.com if you need additional information or 21227825Stheraven * have any questions. 22227825Stheraven * 23227825Stheraven */ 24227825Stheraven 25227825Stheraven// This file contains platform-independent assembler declarations. 26227825Stheraven 27227825Stheravenclass CodeBuffer; 28227825Stheravenclass MacroAssembler; 29227825Stheravenclass AbstractAssembler; 30227825Stheravenclass Label; 31227825Stheraven 32227825Stheraven/** 33227825Stheraven * Labels represent destinations for control transfer instructions. Such 34227825Stheraven * instructions can accept a Label as their target argument. A Label is 35227825Stheraven * bound to the current location in the code stream by calling the 36227825Stheraven * MacroAssembler's 'bind' method, which in turn calls the Label's 'bind' 37227825Stheraven * method. A Label may be referenced by an instruction before it's bound 38227825Stheraven * (i.e., 'forward referenced'). 'bind' stores the current code offset 39227825Stheraven * in the Label object. 40227825Stheraven * 41227825Stheraven * If an instruction references a bound Label, the offset field(s) within 42227825Stheraven * the instruction are immediately filled in based on the Label's code 43227825Stheraven * offset. If an instruction references an unbound label, that 44227825Stheraven * instruction is put on a list of instructions that must be patched 45227825Stheraven * (i.e., 'resolved') when the Label is bound. 46227825Stheraven * 47227825Stheraven * 'bind' will call the platform-specific 'patch_instruction' method to 48227825Stheraven * fill in the offset field(s) for each unresolved instruction (if there 49227825Stheraven * are any). 'patch_instruction' lives in one of the 50227825Stheraven * cpu/<arch>/vm/assembler_<arch>* files. 51227825Stheraven * 52227825Stheraven * Instead of using a linked list of unresolved instructions, a Label has 53227825Stheraven * an array of unresolved instruction code offsets. _patch_index 54227825Stheraven * contains the total number of forward references. If the Label's array 55227825Stheraven * overflows (i.e., _patch_index grows larger than the array size), a 56227825Stheraven * GrowableArray is allocated to hold the remaining offsets. (The cache 57227825Stheraven * size is 4 for now, which handles over 99.5% of the cases) 58227825Stheraven * 59227825Stheraven * Labels may only be used within a single CodeSection. If you need 60227825Stheraven * to create references between code sections, use explicit relocations. 61227825Stheraven */ 62227825Stheravenclass Label VALUE_OBJ_CLASS_SPEC { 63227825Stheraven private: 64227825Stheraven enum { PatchCacheSize = 4 }; 65227825Stheraven 66227825Stheraven // _loc encodes both the binding state (via its sign) 67227825Stheraven // and the binding locator (via its value) of a label. 68227825Stheraven // 69227825Stheraven // _loc >= 0 bound label, loc() encodes the target (jump) position 70227825Stheraven // _loc == -1 unbound label 71227825Stheraven int _loc; 72227825Stheraven 73227825Stheraven // References to instructions that jump to this unresolved label. 74227825Stheraven // These instructions need to be patched when the label is bound 75227825Stheraven // using the platform-specific patchInstruction() method. 76227825Stheraven // 77227825Stheraven // To avoid having to allocate from the C-heap each time, we provide 78227825Stheraven // a local cache and use the overflow only if we exceed the local cache 79227825Stheraven int _patches[PatchCacheSize]; 80227825Stheraven int _patch_index; 81227825Stheraven GrowableArray<int>* _patch_overflow; 82227825Stheraven 83227825Stheraven Label(const Label&) { ShouldNotReachHere(); } 84227825Stheraven 85227825Stheraven public: 86227825Stheraven 87227825Stheraven /** 88227825Stheraven * After binding, be sure 'patch_instructions' is called later to link 89227825Stheraven */ 90227825Stheraven void bind_loc(int loc) { 91227825Stheraven assert(loc >= 0, "illegal locator"); 92227825Stheraven assert(_loc == -1, "already bound"); 93227825Stheraven _loc = loc; 94227825Stheraven } 95227825Stheraven void bind_loc(int pos, int sect); // = bind_loc(locator(pos, sect)) 96227825Stheraven 97227825Stheraven#ifndef PRODUCT 98227825Stheraven // Iterates over all unresolved instructions for printing 99227825Stheraven void print_instructions(MacroAssembler* masm) const; 100227825Stheraven#endif // PRODUCT 101227825Stheraven 102227825Stheraven /** 103227825Stheraven * Returns the position of the the Label in the code buffer 104227825Stheraven * The position is a 'locator', which encodes both offset and section. 105227825Stheraven */ 106227825Stheraven int loc() const { 107227825Stheraven assert(_loc >= 0, "unbound label"); 108227825Stheraven return _loc; 109227825Stheraven } 110227825Stheraven int loc_pos() const; // == locator_pos(loc()) 111227825Stheraven int loc_sect() const; // == locator_sect(loc()) 112227825Stheraven 113227825Stheraven bool is_bound() const { return _loc >= 0; } 114227825Stheraven bool is_unbound() const { return _loc == -1 && _patch_index > 0; } 115227825Stheraven bool is_unused() const { return _loc == -1 && _patch_index == 0; } 116227825Stheraven 117227825Stheraven /** 118227825Stheraven * Adds a reference to an unresolved displacement instruction to 119227825Stheraven * this unbound label 120227825Stheraven * 121227825Stheraven * @param cb the code buffer being patched 122227825Stheraven * @param branch_loc the locator of the branch instruction in the code buffer 123227825Stheraven */ 124227825Stheraven void add_patch_at(CodeBuffer* cb, int branch_loc); 125227825Stheraven 126227825Stheraven /** 127227825Stheraven * Iterate over the list of patches, resolving the instructions 128227825Stheraven * Call patch_instruction on each 'branch_loc' value 129227825Stheraven */ 130227825Stheraven void patch_instructions(MacroAssembler* masm); 131227825Stheraven 132227825Stheraven void init() { 133227825Stheraven _loc = -1; 134227825Stheraven _patch_index = 0; 135227825Stheraven _patch_overflow = NULL; 136227825Stheraven } 137227825Stheraven 138227825Stheraven Label() { 139227825Stheraven init(); 140227825Stheraven } 141227825Stheraven}; 142227825Stheraven 143227825Stheraven 144227825Stheraven// The Abstract Assembler: Pure assembler doing NO optimizations on the 145227825Stheraven// instruction level; i.e., what you write is what you get. 146227825Stheraven// The Assembler is generating code into a CodeBuffer. 147227825Stheravenclass AbstractAssembler : public ResourceObj { 148227825Stheraven friend class Label; 149227825Stheraven 150227825Stheraven protected: 151227825Stheraven CodeSection* _code_section; // section within the code buffer 152227825Stheraven address _code_begin; // first byte of code buffer 153227825Stheraven address _code_limit; // first byte after code buffer 154227825Stheraven address _code_pos; // current code generation position 155227825Stheraven OopRecorder* _oop_recorder; // support for relocInfo::oop_type 156227825Stheraven 157227825Stheraven // Code emission & accessing 158227825Stheraven address addr_at(int pos) const { return _code_begin + pos; } 159227825Stheraven 160227825Stheraven // This routine is called with a label is used for an address. 161227825Stheraven // Labels and displacements truck in offsets, but target must return a PC. 162227825Stheraven address target(Label& L); // return _code_section->target(L) 163227825Stheraven 164227825Stheraven bool is8bit(int x) const { return -0x80 <= x && x < 0x80; } 165227825Stheraven bool isByte(int x) const { return 0 <= x && x < 0x100; } 166227825Stheraven bool isShiftCount(int x) const { return 0 <= x && x < 32; } 167227825Stheraven 168227825Stheraven void emit_byte(int x); // emit a single byte 169227825Stheraven void emit_word(int x); // emit a 16-bit word (not a wordSize word!) 170227825Stheraven void emit_long(jint x); // emit a 32-bit word (not a longSize word!) 171227825Stheraven void emit_address(address x); // emit an address (not a longSize word!) 172227825Stheraven 173227825Stheraven // Instruction boundaries (required when emitting relocatable values). 174227825Stheraven class InstructionMark: public StackObj { 175227825Stheraven private: 176227825Stheraven AbstractAssembler* _assm; 177227825Stheraven 178227825Stheraven public: 179227825Stheraven InstructionMark(AbstractAssembler* assm) : _assm(assm) { 180227825Stheraven assert(assm->inst_mark() == NULL, "overlapping instructions"); 181227825Stheraven _assm->set_inst_mark(); 182227825Stheraven } 183227825Stheraven ~InstructionMark() { 184227825Stheraven _assm->clear_inst_mark(); 185227825Stheraven } 186227825Stheraven }; 187227825Stheraven friend class InstructionMark; 188227825Stheraven #ifdef ASSERT 189227825Stheraven // Make it return true on platforms which need to verify 190227825Stheraven // instruction boundaries for some operations. 191227825Stheraven inline static bool pd_check_instruction_mark(); 192227825Stheraven #endif 193227825Stheraven 194227825Stheraven // Label functions 195227825Stheraven void print(Label& L); 196227825Stheraven 197227825Stheraven public: 198227825Stheraven 199227825Stheraven // Creation 200227825Stheraven AbstractAssembler(CodeBuffer* code); 201227825Stheraven 202227825Stheraven // save end pointer back to code buf. 203227825Stheraven void sync(); 204227825Stheraven 205227825Stheraven // ensure buf contains all code (call this before using/copying the code) 206227825Stheraven void flush(); 207227825Stheraven 208227825Stheraven // Accessors 209227825Stheraven CodeBuffer* code() const; // _code_section->outer() 210227825Stheraven CodeSection* code_section() const { return _code_section; } 211227825Stheraven int sect() const; // return _code_section->index() 212227825Stheraven address pc() const { return _code_pos; } 213227825Stheraven int offset() const { return _code_pos - _code_begin; } 214227825Stheraven int locator() const; // CodeBuffer::locator(offset(), sect()) 215227825Stheraven OopRecorder* oop_recorder() const { return _oop_recorder; } 216227825Stheraven void set_oop_recorder(OopRecorder* r) { _oop_recorder = r; } 217227825Stheraven 218227825Stheraven address inst_mark() const; 219227825Stheraven void set_inst_mark(); 220227825Stheraven void clear_inst_mark(); 221227825Stheraven 222227825Stheraven // Constants in code 223227825Stheraven void a_byte(int x); 224227825Stheraven void a_long(jint x); 225227825Stheraven void relocate(RelocationHolder const& rspec, int format = 0); 226227825Stheraven void relocate( relocInfo::relocType rtype, int format = 0) { 227227825Stheraven if (rtype != relocInfo::none) 228227825Stheraven relocate(Relocation::spec_simple(rtype), format); 229227825Stheraven } 230227825Stheraven 231227825Stheraven static int code_fill_byte(); // used to pad out odd-sized code buffers 232227825Stheraven 233227825Stheraven // Associate a comment with the current offset. It will be printed 234227825Stheraven // along with the disassembly when printing nmethods. Currently 235227825Stheraven // only supported in the instruction section of the code buffer. 236227825Stheraven void block_comment(const char* comment); 237227825Stheraven 238227825Stheraven // Label functions 239227825Stheraven void bind(Label& L); // binds an unbound label L to the current code position 240227825Stheraven 241227825Stheraven // Move to a different section in the same code buffer. 242227825Stheraven void set_code_section(CodeSection* cs); 243227825Stheraven 244227825Stheraven // Inform assembler when generating stub code and relocation info 245227825Stheraven address start_a_stub(int required_space); 246227825Stheraven void end_a_stub(); 247227825Stheraven // Ditto for constants. 248227825Stheraven address start_a_const(int required_space, int required_align = sizeof(double)); 249227825Stheraven void end_a_const(); 250227825Stheraven 251227825Stheraven // fp constants support 252227825Stheraven address double_constant(jdouble c) { 253227825Stheraven address ptr = start_a_const(sizeof(c), sizeof(c)); 254227825Stheraven if (ptr != NULL) { 255227825Stheraven *(jdouble*)ptr = c; 256227825Stheraven _code_pos = ptr + sizeof(c); 257227825Stheraven end_a_const(); 258227825Stheraven } 259227825Stheraven return ptr; 260227825Stheraven } 261227825Stheraven address float_constant(jfloat c) { 262227825Stheraven address ptr = start_a_const(sizeof(c), sizeof(c)); 263227825Stheraven if (ptr != NULL) { 264227825Stheraven *(jfloat*)ptr = c; 265227825Stheraven _code_pos = ptr + sizeof(c); 266227825Stheraven end_a_const(); 267227825Stheraven } 268227825Stheraven return ptr; 269227825Stheraven } 270227825Stheraven address address_constant(address c, RelocationHolder const& rspec) { 271227825Stheraven address ptr = start_a_const(sizeof(c), sizeof(c)); 272227825Stheraven if (ptr != NULL) { 273227825Stheraven relocate(rspec); 274227825Stheraven *(address*)ptr = c; 275227825Stheraven _code_pos = ptr + sizeof(c); 276227825Stheraven end_a_const(); 277227825Stheraven } 278227825Stheraven return ptr; 279227825Stheraven } 280227825Stheraven inline address address_constant(Label& L); 281227825Stheraven inline address address_table_constant(GrowableArray<Label*> label); 282227825Stheraven 283227825Stheraven // Bang stack to trigger StackOverflowError at a safe location 284227825Stheraven // implementation delegates to machine-specific bang_stack_with_offset 285227825Stheraven void generate_stack_overflow_check( int frame_size_in_bytes ); 286227825Stheraven virtual void bang_stack_with_offset(int offset) = 0; 287227825Stheraven 288227825Stheraven 289227825Stheraven /** 290227825Stheraven * A platform-dependent method to patch a jump instruction that refers 291227825Stheraven * to this label. 292227825Stheraven * 293227825Stheraven * @param branch the location of the instruction to patch 294227825Stheraven * @param masm the assembler which generated the branch 295227825Stheraven */ 296227825Stheraven void pd_patch_instruction(address branch, address target); 297227825Stheraven 298227825Stheraven#ifndef PRODUCT 299227825Stheraven /** 300227825Stheraven * Platform-dependent method of printing an instruction that needs to be 301227825Stheraven * patched. 302227825Stheraven * 303227825Stheraven * @param branch the instruction to be patched in the buffer. 304227825Stheraven */ 305227825Stheraven static void pd_print_patched_instruction(address branch); 306227825Stheraven#endif // PRODUCT 307227825Stheraven}; 308227825Stheraven 309227825Stheraven#include "incls/_assembler_pd.hpp.incl" 310227825Stheraven