assembler.hpp revision 2273:1d1603768966
1/* 2 * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25#ifndef SHARE_VM_ASM_ASSEMBLER_HPP 26#define SHARE_VM_ASM_ASSEMBLER_HPP 27 28#include "code/oopRecorder.hpp" 29#include "code/relocInfo.hpp" 30#include "memory/allocation.hpp" 31#include "utilities/debug.hpp" 32#include "utilities/growableArray.hpp" 33#include "utilities/top.hpp" 34#ifdef TARGET_ARCH_x86 35# include "register_x86.hpp" 36# include "vm_version_x86.hpp" 37#endif 38#ifdef TARGET_ARCH_sparc 39# include "register_sparc.hpp" 40# include "vm_version_sparc.hpp" 41#endif 42#ifdef TARGET_ARCH_zero 43# include "register_zero.hpp" 44# include "vm_version_zero.hpp" 45#endif 46#ifdef TARGET_ARCH_arm 47# include "register_arm.hpp" 48# include "vm_version_arm.hpp" 49#endif 50#ifdef TARGET_ARCH_ppc 51# include "register_ppc.hpp" 52# include "vm_version_ppc.hpp" 53#endif 54 55// This file contains platform-independent assembler declarations. 56 57class CodeBuffer; 58class MacroAssembler; 59class AbstractAssembler; 60class Label; 61 62/** 63 * Labels represent destinations for control transfer instructions. Such 64 * instructions can accept a Label as their target argument. A Label is 65 * bound to the current location in the code stream by calling the 66 * MacroAssembler's 'bind' method, which in turn calls the Label's 'bind' 67 * method. A Label may be referenced by an instruction before it's bound 68 * (i.e., 'forward referenced'). 'bind' stores the current code offset 69 * in the Label object. 70 * 71 * If an instruction references a bound Label, the offset field(s) within 72 * the instruction are immediately filled in based on the Label's code 73 * offset. If an instruction references an unbound label, that 74 * instruction is put on a list of instructions that must be patched 75 * (i.e., 'resolved') when the Label is bound. 76 * 77 * 'bind' will call the platform-specific 'patch_instruction' method to 78 * fill in the offset field(s) for each unresolved instruction (if there 79 * are any). 'patch_instruction' lives in one of the 80 * cpu/<arch>/vm/assembler_<arch>* files. 81 * 82 * Instead of using a linked list of unresolved instructions, a Label has 83 * an array of unresolved instruction code offsets. _patch_index 84 * contains the total number of forward references. If the Label's array 85 * overflows (i.e., _patch_index grows larger than the array size), a 86 * GrowableArray is allocated to hold the remaining offsets. (The cache 87 * size is 4 for now, which handles over 99.5% of the cases) 88 * 89 * Labels may only be used within a single CodeSection. If you need 90 * to create references between code sections, use explicit relocations. 91 */ 92class Label VALUE_OBJ_CLASS_SPEC { 93 private: 94 enum { PatchCacheSize = 4 }; 95 96 // _loc encodes both the binding state (via its sign) 97 // and the binding locator (via its value) of a label. 98 // 99 // _loc >= 0 bound label, loc() encodes the target (jump) position 100 // _loc == -1 unbound label 101 int _loc; 102 103 // References to instructions that jump to this unresolved label. 104 // These instructions need to be patched when the label is bound 105 // using the platform-specific patchInstruction() method. 106 // 107 // To avoid having to allocate from the C-heap each time, we provide 108 // a local cache and use the overflow only if we exceed the local cache 109 int _patches[PatchCacheSize]; 110 int _patch_index; 111 GrowableArray<int>* _patch_overflow; 112 113 Label(const Label&) { ShouldNotReachHere(); } 114 115 public: 116 117 /** 118 * After binding, be sure 'patch_instructions' is called later to link 119 */ 120 void bind_loc(int loc) { 121 assert(loc >= 0, "illegal locator"); 122 assert(_loc == -1, "already bound"); 123 _loc = loc; 124 } 125 void bind_loc(int pos, int sect); // = bind_loc(locator(pos, sect)) 126 127#ifndef PRODUCT 128 // Iterates over all unresolved instructions for printing 129 void print_instructions(MacroAssembler* masm) const; 130#endif // PRODUCT 131 132 /** 133 * Returns the position of the the Label in the code buffer 134 * The position is a 'locator', which encodes both offset and section. 135 */ 136 int loc() const { 137 assert(_loc >= 0, "unbound label"); 138 return _loc; 139 } 140 int loc_pos() const; // == locator_pos(loc()) 141 int loc_sect() const; // == locator_sect(loc()) 142 143 bool is_bound() const { return _loc >= 0; } 144 bool is_unbound() const { return _loc == -1 && _patch_index > 0; } 145 bool is_unused() const { return _loc == -1 && _patch_index == 0; } 146 147 /** 148 * Adds a reference to an unresolved displacement instruction to 149 * this unbound label 150 * 151 * @param cb the code buffer being patched 152 * @param branch_loc the locator of the branch instruction in the code buffer 153 */ 154 void add_patch_at(CodeBuffer* cb, int branch_loc); 155 156 /** 157 * Iterate over the list of patches, resolving the instructions 158 * Call patch_instruction on each 'branch_loc' value 159 */ 160 void patch_instructions(MacroAssembler* masm); 161 162 void init() { 163 _loc = -1; 164 _patch_index = 0; 165 _patch_overflow = NULL; 166 } 167 168 Label() { 169 init(); 170 } 171}; 172 173// A union type for code which has to assemble both constant and 174// non-constant operands, when the distinction cannot be made 175// statically. 176class RegisterOrConstant VALUE_OBJ_CLASS_SPEC { 177 private: 178 Register _r; 179 intptr_t _c; 180 181 public: 182 RegisterOrConstant(): _r(noreg), _c(0) {} 183 RegisterOrConstant(Register r): _r(r), _c(0) {} 184 RegisterOrConstant(intptr_t c): _r(noreg), _c(c) {} 185 186 Register as_register() const { assert(is_register(),""); return _r; } 187 intptr_t as_constant() const { assert(is_constant(),""); return _c; } 188 189 Register register_or_noreg() const { return _r; } 190 intptr_t constant_or_zero() const { return _c; } 191 192 bool is_register() const { return _r != noreg; } 193 bool is_constant() const { return _r == noreg; } 194}; 195 196// The Abstract Assembler: Pure assembler doing NO optimizations on the 197// instruction level; i.e., what you write is what you get. 198// The Assembler is generating code into a CodeBuffer. 199class AbstractAssembler : public ResourceObj { 200 friend class Label; 201 202 protected: 203 CodeSection* _code_section; // section within the code buffer 204 address _code_begin; // first byte of code buffer 205 address _code_limit; // first byte after code buffer 206 address _code_pos; // current code generation position 207 OopRecorder* _oop_recorder; // support for relocInfo::oop_type 208 209 // Code emission & accessing 210 address addr_at(int pos) const { return _code_begin + pos; } 211 212 // This routine is called with a label is used for an address. 213 // Labels and displacements truck in offsets, but target must return a PC. 214 address target(Label& L); // return _code_section->target(L) 215 216 bool is8bit(int x) const { return -0x80 <= x && x < 0x80; } 217 bool isByte(int x) const { return 0 <= x && x < 0x100; } 218 bool isShiftCount(int x) const { return 0 <= x && x < 32; } 219 220 void emit_byte(int x); // emit a single byte 221 void emit_word(int x); // emit a 16-bit word (not a wordSize word!) 222 void emit_long(jint x); // emit a 32-bit word (not a longSize word!) 223 void emit_address(address x); // emit an address (not a longSize word!) 224 225 // Instruction boundaries (required when emitting relocatable values). 226 class InstructionMark: public StackObj { 227 private: 228 AbstractAssembler* _assm; 229 230 public: 231 InstructionMark(AbstractAssembler* assm) : _assm(assm) { 232 assert(assm->inst_mark() == NULL, "overlapping instructions"); 233 _assm->set_inst_mark(); 234 } 235 ~InstructionMark() { 236 _assm->clear_inst_mark(); 237 } 238 }; 239 friend class InstructionMark; 240 #ifdef ASSERT 241 // Make it return true on platforms which need to verify 242 // instruction boundaries for some operations. 243 inline static bool pd_check_instruction_mark(); 244 #endif 245 246 // Label functions 247 void print(Label& L); 248 249 public: 250 251 // Creation 252 AbstractAssembler(CodeBuffer* code); 253 254 // save end pointer back to code buf. 255 void sync(); 256 257 // ensure buf contains all code (call this before using/copying the code) 258 void flush(); 259 260 // Accessors 261 CodeBuffer* code() const; // _code_section->outer() 262 CodeSection* code_section() const { return _code_section; } 263 int sect() const; // return _code_section->index() 264 address pc() const { return _code_pos; } 265 int offset() const { return _code_pos - _code_begin; } 266 int locator() const; // CodeBuffer::locator(offset(), sect()) 267 OopRecorder* oop_recorder() const { return _oop_recorder; } 268 void set_oop_recorder(OopRecorder* r) { _oop_recorder = r; } 269 270 address inst_mark() const; 271 void set_inst_mark(); 272 void clear_inst_mark(); 273 274 // Constants in code 275 void a_byte(int x); 276 void a_long(jint x); 277 void relocate(RelocationHolder const& rspec, int format = 0); 278 void relocate( relocInfo::relocType rtype, int format = 0) { 279 if (rtype != relocInfo::none) 280 relocate(Relocation::spec_simple(rtype), format); 281 } 282 283 static int code_fill_byte(); // used to pad out odd-sized code buffers 284 285 // Associate a comment with the current offset. It will be printed 286 // along with the disassembly when printing nmethods. Currently 287 // only supported in the instruction section of the code buffer. 288 void block_comment(const char* comment); 289 290 // Label functions 291 void bind(Label& L); // binds an unbound label L to the current code position 292 293 // Move to a different section in the same code buffer. 294 void set_code_section(CodeSection* cs); 295 296 // Inform assembler when generating stub code and relocation info 297 address start_a_stub(int required_space); 298 void end_a_stub(); 299 // Ditto for constants. 300 address start_a_const(int required_space, int required_align = sizeof(double)); 301 void end_a_const(); 302 303 // constants support 304 address long_constant(jlong c) { 305 address ptr = start_a_const(sizeof(c), sizeof(c)); 306 if (ptr != NULL) { 307 *(jlong*)ptr = c; 308 _code_pos = ptr + sizeof(c); 309 end_a_const(); 310 } 311 return ptr; 312 } 313 address double_constant(jdouble c) { 314 address ptr = start_a_const(sizeof(c), sizeof(c)); 315 if (ptr != NULL) { 316 *(jdouble*)ptr = c; 317 _code_pos = ptr + sizeof(c); 318 end_a_const(); 319 } 320 return ptr; 321 } 322 address float_constant(jfloat c) { 323 address ptr = start_a_const(sizeof(c), sizeof(c)); 324 if (ptr != NULL) { 325 *(jfloat*)ptr = c; 326 _code_pos = ptr + sizeof(c); 327 end_a_const(); 328 } 329 return ptr; 330 } 331 address address_constant(address c) { 332 address ptr = start_a_const(sizeof(c), sizeof(c)); 333 if (ptr != NULL) { 334 *(address*)ptr = c; 335 _code_pos = ptr + sizeof(c); 336 end_a_const(); 337 } 338 return ptr; 339 } 340 address address_constant(address c, RelocationHolder const& rspec) { 341 address ptr = start_a_const(sizeof(c), sizeof(c)); 342 if (ptr != NULL) { 343 relocate(rspec); 344 *(address*)ptr = c; 345 _code_pos = ptr + sizeof(c); 346 end_a_const(); 347 } 348 return ptr; 349 } 350 351 // Bootstrapping aid to cope with delayed determination of constants. 352 // Returns a static address which will eventually contain the constant. 353 // The value zero (NULL) stands instead of a constant which is still uncomputed. 354 // Thus, the eventual value of the constant must not be zero. 355 // This is fine, since this is designed for embedding object field 356 // offsets in code which must be generated before the object class is loaded. 357 // Field offsets are never zero, since an object's header (mark word) 358 // is located at offset zero. 359 RegisterOrConstant delayed_value(int(*value_fn)(), Register tmp, int offset = 0) { 360 return delayed_value_impl(delayed_value_addr(value_fn), tmp, offset); 361 } 362 RegisterOrConstant delayed_value(address(*value_fn)(), Register tmp, int offset = 0) { 363 return delayed_value_impl(delayed_value_addr(value_fn), tmp, offset); 364 } 365 virtual RegisterOrConstant delayed_value_impl(intptr_t* delayed_value_addr, Register tmp, int offset) = 0; 366 // Last overloading is platform-dependent; look in assembler_<arch>.cpp. 367 static intptr_t* delayed_value_addr(int(*constant_fn)()); 368 static intptr_t* delayed_value_addr(address(*constant_fn)()); 369 static void update_delayed_values(); 370 371 // Bang stack to trigger StackOverflowError at a safe location 372 // implementation delegates to machine-specific bang_stack_with_offset 373 void generate_stack_overflow_check( int frame_size_in_bytes ); 374 virtual void bang_stack_with_offset(int offset) = 0; 375 376 377 /** 378 * A platform-dependent method to patch a jump instruction that refers 379 * to this label. 380 * 381 * @param branch the location of the instruction to patch 382 * @param masm the assembler which generated the branch 383 */ 384 void pd_patch_instruction(address branch, address target); 385 386#ifndef PRODUCT 387 /** 388 * Platform-dependent method of printing an instruction that needs to be 389 * patched. 390 * 391 * @param branch the instruction to be patched in the buffer. 392 */ 393 static void pd_print_patched_instruction(address branch); 394#endif // PRODUCT 395}; 396 397#ifdef TARGET_ARCH_x86 398# include "assembler_x86.hpp" 399#endif 400#ifdef TARGET_ARCH_sparc 401# include "assembler_sparc.hpp" 402#endif 403#ifdef TARGET_ARCH_zero 404# include "assembler_zero.hpp" 405#endif 406#ifdef TARGET_ARCH_arm 407# include "assembler_arm.hpp" 408#endif 409#ifdef TARGET_ARCH_ppc 410# include "assembler_ppc.hpp" 411#endif 412 413 414#endif // SHARE_VM_ASM_ASSEMBLER_HPP 415