1 /* 2 * Copyright (c) 1997, 2012, 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 "asm/codeBuffer.hpp" 29 #include "code/oopRecorder.hpp" 30 #include "code/relocInfo.hpp" 31 #include "memory/allocation.hpp" 32 #include "utilities/debug.hpp" 33 #include "utilities/growableArray.hpp" 34 #include "utilities/top.hpp" 35 36 #ifdef TARGET_ARCH_x86 37 # include "register_x86.hpp" 38 # include "vm_version_x86.hpp" 39 #endif 40 #ifdef TARGET_ARCH_sparc 41 # include "register_sparc.hpp" 42 # include "vm_version_sparc.hpp" 43 #endif 44 #ifdef TARGET_ARCH_zero 45 # include "register_zero.hpp" 46 # include "vm_version_zero.hpp" 47 #endif 48 #ifdef TARGET_ARCH_arm 49 # include "register_arm.hpp" 50 # include "vm_version_arm.hpp" 51 #endif 52 #ifdef TARGET_ARCH_ppc 53 # include "register_ppc.hpp" 54 # include "vm_version_ppc.hpp" 55 #endif 56 57 // This file contains platform-independent assembler declarations. 58 59 class MacroAssembler; 60 class AbstractAssembler; 61 class Label; 62 63 /** 64 * Labels represent destinations for control transfer instructions. Such 65 * instructions can accept a Label as their target argument. A Label is 66 * bound to the current location in the code stream by calling the 67 * MacroAssembler's 'bind' method, which in turn calls the Label's 'bind' 68 * method. A Label may be referenced by an instruction before it's bound 69 * (i.e., 'forward referenced'). 'bind' stores the current code offset 70 * in the Label object. 71 * 72 * If an instruction references a bound Label, the offset field(s) within 73 * the instruction are immediately filled in based on the Label's code 74 * offset. If an instruction references an unbound label, that 75 * instruction is put on a list of instructions that must be patched 76 * (i.e., 'resolved') when the Label is bound. 77 * 78 * 'bind' will call the platform-specific 'patch_instruction' method to 79 * fill in the offset field(s) for each unresolved instruction (if there 80 * are any). 'patch_instruction' lives in one of the 81 * cpu/<arch>/vm/assembler_<arch>* files. 82 * 83 * Instead of using a linked list of unresolved instructions, a Label has 84 * an array of unresolved instruction code offsets. _patch_index 85 * contains the total number of forward references. If the Label's array 86 * overflows (i.e., _patch_index grows larger than the array size), a 87 * GrowableArray is allocated to hold the remaining offsets. (The cache 88 * size is 4 for now, which handles over 99.5% of the cases) 89 * 90 * Labels may only be used within a single CodeSection. If you need 91 * to create references between code sections, use explicit relocations. 92 */ 93 class Label VALUE_OBJ_CLASS_SPEC { 94 private: 95 enum { PatchCacheSize = 4 }; 96 97 // _loc encodes both the binding state (via its sign) 98 // and the binding locator (via its value) of a label. 99 // 100 // _loc >= 0 bound label, loc() encodes the target (jump) position 101 // _loc == -1 unbound label 102 int _loc; 103 104 // References to instructions that jump to this unresolved label. 105 // These instructions need to be patched when the label is bound 106 // using the platform-specific patchInstruction() method. 107 // 108 // To avoid having to allocate from the C-heap each time, we provide 109 // a local cache and use the overflow only if we exceed the local cache 110 int _patches[PatchCacheSize]; 111 int _patch_index; 112 GrowableArray<int>* _patch_overflow; 113 114 Label(const Label&) { ShouldNotReachHere(); } 115 116 public: 117 118 /** 119 * After binding, be sure 'patch_instructions' is called later to link 120 */ 121 void bind_loc(int loc) { 122 assert(loc >= 0, "illegal locator"); 123 assert(_loc == -1, "already bound"); 124 _loc = loc; 125 } 126 void bind_loc(int pos, int sect) { bind_loc(CodeBuffer::locator(pos, sect)); } 127 128 #ifndef PRODUCT 129 // Iterates over all unresolved instructions for printing 130 void print_instructions(MacroAssembler* masm) const; 131 #endif // PRODUCT 132 133 /** 134 * Returns the position of the the Label in the code buffer 135 * The position is a 'locator', which encodes both offset and section. 136 */ 137 int loc() const { 138 assert(_loc >= 0, "unbound label"); 139 return _loc; 140 } 141 int loc_pos() const { return CodeBuffer::locator_pos(loc()); } 142 int loc_sect() const { return CodeBuffer::locator_sect(loc()); } 143 144 bool is_bound() const { return _loc >= 0; } 145 bool is_unbound() const { return _loc == -1 && _patch_index > 0; } 146 bool is_unused() const { return _loc == -1 && _patch_index == 0; } 147 148 /** 149 * Adds a reference to an unresolved displacement instruction to 150 * this unbound label 151 * 152 * @param cb the code buffer being patched 153 * @param branch_loc the locator of the branch instruction in the code buffer 154 */ 155 void add_patch_at(CodeBuffer* cb, int branch_loc); 156 157 /** 158 * Iterate over the list of patches, resolving the instructions 159 * Call patch_instruction on each 'branch_loc' value 160 */ 161 void patch_instructions(MacroAssembler* masm); 162 163 void init() { 164 _loc = -1; 165 _patch_index = 0; 166 _patch_overflow = NULL; 167 } 168 169 Label() { 170 init(); 171 } 172 }; 173 174 // A union type for code which has to assemble both constant and 175 // non-constant operands, when the distinction cannot be made 176 // statically. 177 class RegisterOrConstant VALUE_OBJ_CLASS_SPEC { 178 private: 179 Register _r; 180 intptr_t _c; 181 182 public: 183 RegisterOrConstant(): _r(noreg), _c(0) {} 184 RegisterOrConstant(Register r): _r(r), _c(0) {} 185 RegisterOrConstant(intptr_t c): _r(noreg), _c(c) {} 186 187 Register as_register() const { assert(is_register(),""); return _r; } 188 intptr_t as_constant() const { assert(is_constant(),""); return _c; } 189 190 Register register_or_noreg() const { return _r; } 191 intptr_t constant_or_zero() const { return _c; } 192 193 bool is_register() const { return _r != noreg; } 194 bool is_constant() const { return _r == noreg; } 195 }; 196 197 // The Abstract Assembler: Pure assembler doing NO optimizations on the 198 // instruction level; i.e., what you write is what you get. 199 // The Assembler is generating code into a CodeBuffer. 200 class AbstractAssembler : public ResourceObj { 201 friend class Label; 202 203 protected: 204 CodeSection* _code_section; // section within the code buffer 205 OopRecorder* _oop_recorder; // support for relocInfo::oop_type 206 207 // Code emission & accessing 208 address addr_at(int pos) const { return code_section()->start() + pos; } 209 210 211 // This routine is called with a label is used for an address. 212 // Labels and displacements truck in offsets, but target must return a PC. 213 address target(Label& L) { return code_section()->target(L, pc()); } 214 215 bool is8bit(int x) const { return -0x80 <= x && x < 0x80; } 216 bool isByte(int x) const { return 0 <= x && x < 0x100; } 217 bool isShiftCount(int x) const { return 0 <= x && x < 32; } 218 219 void emit_word(int x) { emit_int16(x); } // deprecated 220 void emit_long(jint x) { emit_int32(x); } // deprecated 221 222 // Instruction boundaries (required when emitting relocatable values). 223 class InstructionMark: public StackObj { 224 private: 225 AbstractAssembler* _assm; 226 227 public: 228 InstructionMark(AbstractAssembler* assm) : _assm(assm) { 229 assert(assm->inst_mark() == NULL, "overlapping instructions"); 230 _assm->set_inst_mark(); 231 } 232 ~InstructionMark() { 233 _assm->clear_inst_mark(); 234 } 235 }; 236 friend class InstructionMark; 237 #ifdef ASSERT 238 // Make it return true on platforms which need to verify 239 // instruction boundaries for some operations. 240 static bool pd_check_instruction_mark(); 241 242 // Add delta to short branch distance to verify that it still fit into imm8. 243 int _short_branch_delta; 244 245 int short_branch_delta() const { return _short_branch_delta; } 246 void set_short_branch_delta() { _short_branch_delta = 32; } 247 void clear_short_branch_delta() { _short_branch_delta = 0; } 248 249 class ShortBranchVerifier: public StackObj { 250 private: 251 AbstractAssembler* _assm; 252 253 public: 254 ShortBranchVerifier(AbstractAssembler* assm) : _assm(assm) { 255 assert(assm->short_branch_delta() == 0, "overlapping instructions"); 256 _assm->set_short_branch_delta(); 257 } 258 ~ShortBranchVerifier() { 259 _assm->clear_short_branch_delta(); 260 } 261 }; 262 #else 263 // Dummy in product. 264 class ShortBranchVerifier: public StackObj { 265 public: 266 ShortBranchVerifier(AbstractAssembler* assm) {} 267 }; 268 #endif 269 270 // Label functions 271 void print(Label& L); 272 273 public: 274 275 // Creation 276 AbstractAssembler(CodeBuffer* code); 277 278 // ensure buf contains all code (call this before using/copying the code) 279 void flush(); 280 281 void emit_int8( int8_t x) { code_section()->emit_int8( x); } 282 void emit_int16( int16_t x) { code_section()->emit_int16( x); } 283 void emit_int32( int32_t x) { code_section()->emit_int32( x); } 284 void emit_int64( int64_t x) { code_section()->emit_int64( x); } 285 286 void emit_float( jfloat x) { code_section()->emit_float( x); } 287 void emit_double( jdouble x) { code_section()->emit_double( x); } 288 void emit_address(address x) { code_section()->emit_address(x); } 289 290 // min and max values for signed immediate ranges 291 static int min_simm(int nbits) { return -(intptr_t(1) << (nbits - 1)) ; } 292 static int max_simm(int nbits) { return (intptr_t(1) << (nbits - 1)) - 1; } 293 294 // Define some: 295 static int min_simm10() { return min_simm(10); } 296 static int min_simm13() { return min_simm(13); } 297 static int min_simm16() { return min_simm(16); } 298 299 // Test if x is within signed immediate range for nbits 300 static bool is_simm(intptr_t x, int nbits) { return min_simm(nbits) <= x && x <= max_simm(nbits); } 301 302 // Define some: 303 static bool is_simm5( intptr_t x) { return is_simm(x, 5 ); } 304 static bool is_simm8( intptr_t x) { return is_simm(x, 8 ); } 305 static bool is_simm10(intptr_t x) { return is_simm(x, 10); } 306 static bool is_simm11(intptr_t x) { return is_simm(x, 11); } 307 static bool is_simm12(intptr_t x) { return is_simm(x, 12); } 308 static bool is_simm13(intptr_t x) { return is_simm(x, 13); } 309 static bool is_simm16(intptr_t x) { return is_simm(x, 16); } 310 static bool is_simm26(intptr_t x) { return is_simm(x, 26); } 311 static bool is_simm32(intptr_t x) { return is_simm(x, 32); } 312 313 // Accessors 314 CodeSection* code_section() const { return _code_section; } 315 CodeBuffer* code() const { return code_section()->outer(); } 316 int sect() const { return code_section()->index(); } 317 address pc() const { return code_section()->end(); } 318 int offset() const { return code_section()->size(); } 319 int locator() const { return CodeBuffer::locator(offset(), sect()); } 320 321 OopRecorder* oop_recorder() const { return _oop_recorder; } 322 void set_oop_recorder(OopRecorder* r) { _oop_recorder = r; } 323 324 address inst_mark() const { return code_section()->mark(); } 325 void set_inst_mark() { code_section()->set_mark(); } 326 void clear_inst_mark() { code_section()->clear_mark(); } 327 328 // Constants in code 329 void relocate(RelocationHolder const& rspec, int format = 0) { 330 assert(!pd_check_instruction_mark() 331 || inst_mark() == NULL || inst_mark() == code_section()->end(), 332 "call relocate() between instructions"); 333 code_section()->relocate(code_section()->end(), rspec, format); 334 } 335 void relocate( relocInfo::relocType rtype, int format = 0) { 336 code_section()->relocate(code_section()->end(), rtype, format); 337 } 338 339 static int code_fill_byte(); // used to pad out odd-sized code buffers 340 341 // Associate a comment with the current offset. It will be printed 342 // along with the disassembly when printing nmethods. Currently 343 // only supported in the instruction section of the code buffer. 344 void block_comment(const char* comment); 345 346 // Label functions 347 void bind(Label& L); // binds an unbound label L to the current code position 348 349 // Move to a different section in the same code buffer. 350 void set_code_section(CodeSection* cs); 351 352 // Inform assembler when generating stub code and relocation info 353 address start_a_stub(int required_space); 354 void end_a_stub(); 355 // Ditto for constants. 356 address start_a_const(int required_space, int required_align = sizeof(double)); 357 void end_a_const(CodeSection* cs); // Pass the codesection to continue in (insts or stubs?). 358 359 // constants support 360 // 361 // We must remember the code section (insts or stubs) in c1 362 // so we can reset to the proper section in end_a_const(). 363 address long_constant(jlong c) { 364 CodeSection* c1 = _code_section; 365 address ptr = start_a_const(sizeof(c), sizeof(c)); 366 if (ptr != NULL) { 367 emit_int64(c); 368 end_a_const(c1); 369 } 370 return ptr; 371 } 372 address double_constant(jdouble c) { 373 CodeSection* c1 = _code_section; 374 address ptr = start_a_const(sizeof(c), sizeof(c)); 375 if (ptr != NULL) { 376 emit_double(c); 377 end_a_const(c1); 378 } 379 return ptr; 380 } 381 address float_constant(jfloat c) { 382 CodeSection* c1 = _code_section; 383 address ptr = start_a_const(sizeof(c), sizeof(c)); 384 if (ptr != NULL) { 385 emit_float(c); 386 end_a_const(c1); 387 } 388 return ptr; 389 } 390 address address_constant(address c) { 391 CodeSection* c1 = _code_section; 392 address ptr = start_a_const(sizeof(c), sizeof(c)); 393 if (ptr != NULL) { 394 emit_address(c); 395 end_a_const(c1); 396 } 397 return ptr; 398 } 399 address address_constant(address c, RelocationHolder const& rspec) { 400 CodeSection* c1 = _code_section; 401 address ptr = start_a_const(sizeof(c), sizeof(c)); 402 if (ptr != NULL) { 403 relocate(rspec); 404 emit_address(c); 405 end_a_const(c1); 406 } 407 return ptr; 408 } 409 410 // Bootstrapping aid to cope with delayed determination of constants. 411 // Returns a static address which will eventually contain the constant. 412 // The value zero (NULL) stands instead of a constant which is still uncomputed. 413 // Thus, the eventual value of the constant must not be zero. 414 // This is fine, since this is designed for embedding object field 415 // offsets in code which must be generated before the object class is loaded. 416 // Field offsets are never zero, since an object's header (mark word) 417 // is located at offset zero. 418 RegisterOrConstant delayed_value(int(*value_fn)(), Register tmp, int offset = 0); 419 RegisterOrConstant delayed_value(address(*value_fn)(), Register tmp, int offset = 0); 420 virtual RegisterOrConstant delayed_value_impl(intptr_t* delayed_value_addr, Register tmp, int offset) = 0; 421 // Last overloading is platform-dependent; look in assembler_<arch>.cpp. 422 static intptr_t* delayed_value_addr(int(*constant_fn)()); 423 static intptr_t* delayed_value_addr(address(*constant_fn)()); 424 static void update_delayed_values(); 425 426 // Bang stack to trigger StackOverflowError at a safe location 427 // implementation delegates to machine-specific bang_stack_with_offset 428 void generate_stack_overflow_check( int frame_size_in_bytes ); 429 virtual void bang_stack_with_offset(int offset) = 0; 430 431 432 /** 433 * A platform-dependent method to patch a jump instruction that refers 434 * to this label. 435 * 436 * @param branch the location of the instruction to patch 437 * @param masm the assembler which generated the branch 438 */ 439 void pd_patch_instruction(address branch, address target); 440 441 #ifndef PRODUCT 442 /** 443 * Platform-dependent method of printing an instruction that needs to be 444 * patched. 445 * 446 * @param branch the instruction to be patched in the buffer. 447 */ 448 static void pd_print_patched_instruction(address branch); 449 #endif // PRODUCT 450 }; 451 452 #ifdef TARGET_ARCH_x86 453 # include "assembler_x86.hpp" 454 #endif 455 #ifdef TARGET_ARCH_sparc 456 # include "assembler_sparc.hpp" 457 #endif 458 #ifdef TARGET_ARCH_zero 459 # include "assembler_zero.hpp" 460 #endif 461 #ifdef TARGET_ARCH_arm 462 # include "assembler_arm.hpp" 463 #endif 464 #ifdef TARGET_ARCH_ppc 465 # include "assembler_ppc.hpp" 466 #endif 467 468 469 #endif // SHARE_VM_ASM_ASSEMBLER_HPP