Mercurial > hg > truffle
annotate src/share/vm/asm/assembler.hpp @ 622:56aae7be60d4
6812678: macro assembler needs delayed binding of a few constants (for 6655638)
Summary: minor assembler enhancements preparing for method handles
Reviewed-by: kvn
| author | jrose |
|---|---|
| date | Wed, 04 Mar 2009 09:58:39 -0800 |
| parents | 98cb887364d3 |
| children | c89f86385056 |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 * Copyright 1997-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
| 20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
| 21 * have any questions. | |
| 22 * | |
| 23 */ | |
| 24 | |
| 605 | 25 // This file contains platform-independent assembler declarations. |
| 0 | 26 |
| 27 class CodeBuffer; | |
| 28 class MacroAssembler; | |
| 29 class AbstractAssembler; | |
| 30 class Label; | |
| 31 | |
| 32 /** | |
| 33 * Labels represent destinations for control transfer instructions. Such | |
| 34 * instructions can accept a Label as their target argument. A Label is | |
| 35 * bound to the current location in the code stream by calling the | |
| 36 * MacroAssembler's 'bind' method, which in turn calls the Label's 'bind' | |
| 37 * method. A Label may be referenced by an instruction before it's bound | |
| 38 * (i.e., 'forward referenced'). 'bind' stores the current code offset | |
| 39 * in the Label object. | |
| 40 * | |
| 41 * If an instruction references a bound Label, the offset field(s) within | |
| 42 * the instruction are immediately filled in based on the Label's code | |
| 43 * offset. If an instruction references an unbound label, that | |
| 44 * instruction is put on a list of instructions that must be patched | |
| 45 * (i.e., 'resolved') when the Label is bound. | |
| 46 * | |
| 47 * 'bind' will call the platform-specific 'patch_instruction' method to | |
| 48 * fill in the offset field(s) for each unresolved instruction (if there | |
| 49 * are any). 'patch_instruction' lives in one of the | |
| 50 * cpu/<arch>/vm/assembler_<arch>* files. | |
| 51 * | |
| 52 * Instead of using a linked list of unresolved instructions, a Label has | |
| 53 * an array of unresolved instruction code offsets. _patch_index | |
| 54 * contains the total number of forward references. If the Label's array | |
| 55 * overflows (i.e., _patch_index grows larger than the array size), a | |
| 56 * GrowableArray is allocated to hold the remaining offsets. (The cache | |
| 57 * size is 4 for now, which handles over 99.5% of the cases) | |
| 58 * | |
| 59 * Labels may only be used within a single CodeSection. If you need | |
| 60 * to create references between code sections, use explicit relocations. | |
| 61 */ | |
| 62 class Label VALUE_OBJ_CLASS_SPEC { | |
| 63 private: | |
| 64 enum { PatchCacheSize = 4 }; | |
| 65 | |
| 66 // _loc encodes both the binding state (via its sign) | |
| 67 // and the binding locator (via its value) of a label. | |
| 68 // | |
| 69 // _loc >= 0 bound label, loc() encodes the target (jump) position | |
| 70 // _loc == -1 unbound label | |
| 71 int _loc; | |
| 72 | |
| 73 // References to instructions that jump to this unresolved label. | |
| 74 // These instructions need to be patched when the label is bound | |
| 75 // using the platform-specific patchInstruction() method. | |
| 76 // | |
| 77 // To avoid having to allocate from the C-heap each time, we provide | |
| 78 // a local cache and use the overflow only if we exceed the local cache | |
| 79 int _patches[PatchCacheSize]; | |
| 80 int _patch_index; | |
| 81 GrowableArray<int>* _patch_overflow; | |
| 82 | |
| 83 Label(const Label&) { ShouldNotReachHere(); } | |
| 84 | |
| 85 public: | |
| 86 | |
| 87 /** | |
| 88 * After binding, be sure 'patch_instructions' is called later to link | |
| 89 */ | |
| 90 void bind_loc(int loc) { | |
| 91 assert(loc >= 0, "illegal locator"); | |
| 92 assert(_loc == -1, "already bound"); | |
| 93 _loc = loc; | |
| 94 } | |
| 95 void bind_loc(int pos, int sect); // = bind_loc(locator(pos, sect)) | |
| 96 | |
| 97 #ifndef PRODUCT | |
| 98 // Iterates over all unresolved instructions for printing | |
| 99 void print_instructions(MacroAssembler* masm) const; | |
| 100 #endif // PRODUCT | |
| 101 | |
| 102 /** | |
| 103 * Returns the position of the the Label in the code buffer | |
| 104 * The position is a 'locator', which encodes both offset and section. | |
| 105 */ | |
| 106 int loc() const { | |
| 107 assert(_loc >= 0, "unbound label"); | |
| 108 return _loc; | |
| 109 } | |
| 110 int loc_pos() const; // == locator_pos(loc()) | |
| 111 int loc_sect() const; // == locator_sect(loc()) | |
| 112 | |
| 113 bool is_bound() const { return _loc >= 0; } | |
| 114 bool is_unbound() const { return _loc == -1 && _patch_index > 0; } | |
| 115 bool is_unused() const { return _loc == -1 && _patch_index == 0; } | |
| 116 | |
| 117 /** | |
| 118 * Adds a reference to an unresolved displacement instruction to | |
| 119 * this unbound label | |
| 120 * | |
| 121 * @param cb the code buffer being patched | |
| 122 * @param branch_loc the locator of the branch instruction in the code buffer | |
| 123 */ | |
| 124 void add_patch_at(CodeBuffer* cb, int branch_loc); | |
| 125 | |
| 126 /** | |
| 127 * Iterate over the list of patches, resolving the instructions | |
| 128 * Call patch_instruction on each 'branch_loc' value | |
| 129 */ | |
| 130 void patch_instructions(MacroAssembler* masm); | |
| 131 | |
| 132 void init() { | |
| 133 _loc = -1; | |
| 134 _patch_index = 0; | |
| 135 _patch_overflow = NULL; | |
| 136 } | |
| 137 | |
| 138 Label() { | |
| 139 init(); | |
| 140 } | |
| 141 }; | |
| 142 | |
|
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143 // A union type for code which has to assemble both constant and |
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144 // non-constant operands, when the distinction cannot be made |
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145 // statically. |
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146 class RegisterConstant VALUE_OBJ_CLASS_SPEC { |
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147 private: |
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148 Register _r; |
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149 intptr_t _c; |
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150 |
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151 public: |
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152 RegisterConstant(): _r(noreg), _c(0) {} |
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153 RegisterConstant(Register r): _r(r), _c(0) {} |
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154 RegisterConstant(intptr_t c): _r(noreg), _c(c) {} |
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155 |
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156 Register as_register() const { assert(is_register(),""); return _r; } |
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157 intptr_t as_constant() const { assert(is_constant(),""); return _c; } |
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158 |
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159 Register register_or_noreg() const { return _r; } |
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160 intptr_t constant_or_zero() const { return _c; } |
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161 |
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162 bool is_register() const { return _r != noreg; } |
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163 bool is_constant() const { return _r == noreg; } |
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164 }; |
| 0 | 165 |
| 166 // The Abstract Assembler: Pure assembler doing NO optimizations on the | |
| 167 // instruction level; i.e., what you write is what you get. | |
| 168 // The Assembler is generating code into a CodeBuffer. | |
| 169 class AbstractAssembler : public ResourceObj { | |
| 170 friend class Label; | |
| 171 | |
| 172 protected: | |
| 173 CodeSection* _code_section; // section within the code buffer | |
| 174 address _code_begin; // first byte of code buffer | |
| 175 address _code_limit; // first byte after code buffer | |
| 176 address _code_pos; // current code generation position | |
| 177 OopRecorder* _oop_recorder; // support for relocInfo::oop_type | |
| 178 | |
| 179 // Code emission & accessing | |
| 180 address addr_at(int pos) const { return _code_begin + pos; } | |
| 181 | |
| 182 // This routine is called with a label is used for an address. | |
| 183 // Labels and displacements truck in offsets, but target must return a PC. | |
| 184 address target(Label& L); // return _code_section->target(L) | |
| 185 | |
| 186 bool is8bit(int x) const { return -0x80 <= x && x < 0x80; } | |
| 187 bool isByte(int x) const { return 0 <= x && x < 0x100; } | |
| 188 bool isShiftCount(int x) const { return 0 <= x && x < 32; } | |
| 189 | |
| 190 void emit_byte(int x); // emit a single byte | |
| 191 void emit_word(int x); // emit a 16-bit word (not a wordSize word!) | |
| 192 void emit_long(jint x); // emit a 32-bit word (not a longSize word!) | |
| 193 void emit_address(address x); // emit an address (not a longSize word!) | |
| 194 | |
| 195 // Instruction boundaries (required when emitting relocatable values). | |
| 196 class InstructionMark: public StackObj { | |
| 197 private: | |
| 198 AbstractAssembler* _assm; | |
| 199 | |
| 200 public: | |
| 201 InstructionMark(AbstractAssembler* assm) : _assm(assm) { | |
| 202 assert(assm->inst_mark() == NULL, "overlapping instructions"); | |
| 203 _assm->set_inst_mark(); | |
| 204 } | |
| 205 ~InstructionMark() { | |
| 206 _assm->clear_inst_mark(); | |
| 207 } | |
| 208 }; | |
| 209 friend class InstructionMark; | |
| 210 #ifdef ASSERT | |
| 211 // Make it return true on platforms which need to verify | |
| 212 // instruction boundaries for some operations. | |
| 213 inline static bool pd_check_instruction_mark(); | |
| 214 #endif | |
| 215 | |
| 216 // Label functions | |
| 217 void print(Label& L); | |
| 218 | |
| 219 public: | |
| 220 | |
| 221 // Creation | |
| 222 AbstractAssembler(CodeBuffer* code); | |
| 223 | |
| 224 // save end pointer back to code buf. | |
| 225 void sync(); | |
| 226 | |
| 227 // ensure buf contains all code (call this before using/copying the code) | |
| 228 void flush(); | |
| 229 | |
| 230 // Accessors | |
| 231 CodeBuffer* code() const; // _code_section->outer() | |
| 232 CodeSection* code_section() const { return _code_section; } | |
| 233 int sect() const; // return _code_section->index() | |
| 234 address pc() const { return _code_pos; } | |
| 235 int offset() const { return _code_pos - _code_begin; } | |
| 236 int locator() const; // CodeBuffer::locator(offset(), sect()) | |
| 237 OopRecorder* oop_recorder() const { return _oop_recorder; } | |
| 238 void set_oop_recorder(OopRecorder* r) { _oop_recorder = r; } | |
| 239 | |
| 240 address inst_mark() const; | |
| 241 void set_inst_mark(); | |
| 242 void clear_inst_mark(); | |
| 243 | |
| 244 // Constants in code | |
| 245 void a_byte(int x); | |
| 246 void a_long(jint x); | |
| 247 void relocate(RelocationHolder const& rspec, int format = 0); | |
| 248 void relocate( relocInfo::relocType rtype, int format = 0) { | |
| 249 if (rtype != relocInfo::none) | |
| 250 relocate(Relocation::spec_simple(rtype), format); | |
| 251 } | |
| 252 | |
| 253 static int code_fill_byte(); // used to pad out odd-sized code buffers | |
| 254 | |
| 255 // Associate a comment with the current offset. It will be printed | |
| 256 // along with the disassembly when printing nmethods. Currently | |
| 257 // only supported in the instruction section of the code buffer. | |
| 258 void block_comment(const char* comment); | |
| 259 | |
| 260 // Label functions | |
| 261 void bind(Label& L); // binds an unbound label L to the current code position | |
| 262 | |
| 263 // Move to a different section in the same code buffer. | |
| 264 void set_code_section(CodeSection* cs); | |
| 265 | |
| 266 // Inform assembler when generating stub code and relocation info | |
| 267 address start_a_stub(int required_space); | |
| 268 void end_a_stub(); | |
| 269 // Ditto for constants. | |
| 270 address start_a_const(int required_space, int required_align = sizeof(double)); | |
| 271 void end_a_const(); | |
| 272 | |
| 273 // fp constants support | |
| 274 address double_constant(jdouble c) { | |
| 275 address ptr = start_a_const(sizeof(c), sizeof(c)); | |
| 276 if (ptr != NULL) { | |
| 277 *(jdouble*)ptr = c; | |
| 278 _code_pos = ptr + sizeof(c); | |
| 279 end_a_const(); | |
| 280 } | |
| 281 return ptr; | |
| 282 } | |
| 283 address float_constant(jfloat c) { | |
| 284 address ptr = start_a_const(sizeof(c), sizeof(c)); | |
| 285 if (ptr != NULL) { | |
| 286 *(jfloat*)ptr = c; | |
| 287 _code_pos = ptr + sizeof(c); | |
| 288 end_a_const(); | |
| 289 } | |
| 290 return ptr; | |
| 291 } | |
| 292 address address_constant(address c, RelocationHolder const& rspec) { | |
| 293 address ptr = start_a_const(sizeof(c), sizeof(c)); | |
| 294 if (ptr != NULL) { | |
| 295 relocate(rspec); | |
| 296 *(address*)ptr = c; | |
| 297 _code_pos = ptr + sizeof(c); | |
| 298 end_a_const(); | |
| 299 } | |
| 300 return ptr; | |
| 301 } | |
| 302 inline address address_constant(Label& L); | |
| 303 inline address address_table_constant(GrowableArray<Label*> label); | |
| 304 | |
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305 // Bootstrapping aid to cope with delayed determination of constants. |
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306 // Returns a static address which will eventually contain the constant. |
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307 // The value zero (NULL) stands instead of a constant which is still uncomputed. |
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308 // Thus, the eventual value of the constant must not be zero. |
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309 // This is fine, since this is designed for embedding object field |
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310 // offsets in code which must be generated before the object class is loaded. |
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311 // Field offsets are never zero, since an object's header (mark word) |
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312 // is located at offset zero. |
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313 RegisterConstant delayed_value(int(*value_fn)(), Register tmp, int offset = 0) { |
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314 return delayed_value(delayed_value_addr(value_fn), tmp, offset); |
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315 } |
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316 RegisterConstant delayed_value(address(*value_fn)(), Register tmp, int offset = 0) { |
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317 return delayed_value(delayed_value_addr(value_fn), tmp, offset); |
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318 } |
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319 virtual RegisterConstant delayed_value(intptr_t* delayed_value_addr, Register tmp, int offset) = 0; |
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320 // Last overloading is platform-dependent; look in assembler_<arch>.cpp. |
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321 static intptr_t* delayed_value_addr(int(*constant_fn)()); |
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322 static intptr_t* delayed_value_addr(address(*constant_fn)()); |
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323 static void update_delayed_values(); |
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324 |
| 0 | 325 // Bang stack to trigger StackOverflowError at a safe location |
| 326 // implementation delegates to machine-specific bang_stack_with_offset | |
| 327 void generate_stack_overflow_check( int frame_size_in_bytes ); | |
| 328 virtual void bang_stack_with_offset(int offset) = 0; | |
| 329 | |
| 330 | |
| 331 /** | |
| 332 * A platform-dependent method to patch a jump instruction that refers | |
| 333 * to this label. | |
| 334 * | |
| 335 * @param branch the location of the instruction to patch | |
| 336 * @param masm the assembler which generated the branch | |
| 337 */ | |
| 338 void pd_patch_instruction(address branch, address target); | |
| 339 | |
| 340 #ifndef PRODUCT | |
| 341 /** | |
| 342 * Platform-dependent method of printing an instruction that needs to be | |
| 343 * patched. | |
| 344 * | |
| 345 * @param branch the instruction to be patched in the buffer. | |
| 346 */ | |
| 347 static void pd_print_patched_instruction(address branch); | |
| 348 #endif // PRODUCT | |
| 349 }; | |
| 350 | |
| 351 #include "incls/_assembler_pd.hpp.incl" |