static_inst.hh revision 2741:a73a50764b86
1/* 2 * Copyright (c) 2003-2005 The Regents of The University of Michigan 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are 7 * met: redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer; 9 * redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution; 12 * neither the name of the copyright holders nor the names of its 13 * contributors may be used to endorse or promote products derived from 14 * this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * Authors: Steve Reinhardt 29 */ 30 31#ifndef __CPU_STATIC_INST_HH__ 32#define __CPU_STATIC_INST_HH__ 33 34#include <bitset> 35#include <string> 36 37#include "base/bitfield.hh" 38#include "base/hashmap.hh" 39#include "base/misc.hh" 40#include "base/refcnt.hh" 41#include "cpu/op_class.hh" 42#include "sim/host.hh" 43#include "arch/isa_traits.hh" 44 45// forward declarations 46struct AlphaSimpleImpl; 47struct OzoneImpl; 48struct SimpleImpl; 49class ThreadContext; 50class DynInst; 51class Packet; 52 53template <class Impl> 54class AlphaDynInst; 55 56template <class Impl> 57class OzoneDynInst; 58 59class CheckerCPU; 60class FastCPU; 61class AtomicSimpleCPU; 62class TimingSimpleCPU; 63class InorderCPU; 64class SymbolTable; 65 66namespace Trace { 67 class InstRecord; 68} 69 70/** 71 * Base, ISA-independent static instruction class. 72 * 73 * The main component of this class is the vector of flags and the 74 * associated methods for reading them. Any object that can rely 75 * solely on these flags can process instructions without being 76 * recompiled for multiple ISAs. 77 */ 78class StaticInstBase : public RefCounted 79{ 80 protected: 81 82 /// Set of boolean static instruction properties. 83 /// 84 /// Notes: 85 /// - The IsInteger and IsFloating flags are based on the class of 86 /// registers accessed by the instruction. Although most 87 /// instructions will have exactly one of these two flags set, it 88 /// is possible for an instruction to have neither (e.g., direct 89 /// unconditional branches, memory barriers) or both (e.g., an 90 /// FP/int conversion). 91 /// - If IsMemRef is set, then exactly one of IsLoad or IsStore 92 /// will be set. 93 /// - If IsControl is set, then exactly one of IsDirectControl or 94 /// IsIndirect Control will be set, and exactly one of 95 /// IsCondControl or IsUncondControl will be set. 96 /// - IsSerializing, IsMemBarrier, and IsWriteBarrier are 97 /// implemented as flags since in the current model there's no 98 /// other way for instructions to inject behavior into the 99 /// pipeline outside of fetch. Once we go to an exec-in-exec CPU 100 /// model we should be able to get rid of these flags and 101 /// implement this behavior via the execute() methods. 102 /// 103 enum Flags { 104 IsNop, ///< Is a no-op (no effect at all). 105 106 IsInteger, ///< References integer regs. 107 IsFloating, ///< References FP regs. 108 109 IsMemRef, ///< References memory (load, store, or prefetch). 110 IsLoad, ///< Reads from memory (load or prefetch). 111 IsStore, ///< Writes to memory. 112 IsStoreConditional, ///< Store conditional instruction. 113 IsInstPrefetch, ///< Instruction-cache prefetch. 114 IsDataPrefetch, ///< Data-cache prefetch. 115 IsCopy, ///< Fast Cache block copy 116 117 IsControl, ///< Control transfer instruction. 118 IsDirectControl, ///< PC relative control transfer. 119 IsIndirectControl, ///< Register indirect control transfer. 120 IsCondControl, ///< Conditional control transfer. 121 IsUncondControl, ///< Unconditional control transfer. 122 IsCall, ///< Subroutine call. 123 IsReturn, ///< Subroutine return. 124 125 IsCondDelaySlot,///< Conditional Delay-Slot Instruction 126 127 IsThreadSync, ///< Thread synchronization operation. 128 129 IsSerializing, ///< Serializes pipeline: won't execute until all 130 /// older instructions have committed. 131 IsSerializeBefore, 132 IsSerializeAfter, 133 IsMemBarrier, ///< Is a memory barrier 134 IsWriteBarrier, ///< Is a write barrier 135 136 IsNonSpeculative, ///< Should not be executed speculatively 137 IsQuiesce, ///< Is a quiesce instruction 138 139 IsIprAccess, ///< Accesses IPRs 140 IsUnverifiable, ///< Can't be verified by a checker 141 142 NumFlags 143 }; 144 145 /// Flag values for this instruction. 146 std::bitset<NumFlags> flags; 147 148 /// See opClass(). 149 OpClass _opClass; 150 151 /// See numSrcRegs(). 152 int8_t _numSrcRegs; 153 154 /// See numDestRegs(). 155 int8_t _numDestRegs; 156 157 /// The following are used to track physical register usage 158 /// for machines with separate int & FP reg files. 159 //@{ 160 int8_t _numFPDestRegs; 161 int8_t _numIntDestRegs; 162 //@} 163 164 /// Constructor. 165 /// It's important to initialize everything here to a sane 166 /// default, since the decoder generally only overrides 167 /// the fields that are meaningful for the particular 168 /// instruction. 169 StaticInstBase(OpClass __opClass) 170 : _opClass(__opClass), _numSrcRegs(0), _numDestRegs(0), 171 _numFPDestRegs(0), _numIntDestRegs(0) 172 { 173 } 174 175 public: 176 177 /// @name Register information. 178 /// The sum of numFPDestRegs() and numIntDestRegs() equals 179 /// numDestRegs(). The former two functions are used to track 180 /// physical register usage for machines with separate int & FP 181 /// reg files. 182 //@{ 183 /// Number of source registers. 184 int8_t numSrcRegs() const { return _numSrcRegs; } 185 /// Number of destination registers. 186 int8_t numDestRegs() const { return _numDestRegs; } 187 /// Number of floating-point destination regs. 188 int8_t numFPDestRegs() const { return _numFPDestRegs; } 189 /// Number of integer destination regs. 190 int8_t numIntDestRegs() const { return _numIntDestRegs; } 191 //@} 192 193 /// @name Flag accessors. 194 /// These functions are used to access the values of the various 195 /// instruction property flags. See StaticInstBase::Flags for descriptions 196 /// of the individual flags. 197 //@{ 198 199 bool isNop() const { return flags[IsNop]; } 200 201 bool isMemRef() const { return flags[IsMemRef]; } 202 bool isLoad() const { return flags[IsLoad]; } 203 bool isStore() const { return flags[IsStore]; } 204 bool isStoreConditional() const { return flags[IsStoreConditional]; } 205 bool isInstPrefetch() const { return flags[IsInstPrefetch]; } 206 bool isDataPrefetch() const { return flags[IsDataPrefetch]; } 207 bool isCopy() const { return flags[IsCopy];} 208 209 bool isInteger() const { return flags[IsInteger]; } 210 bool isFloating() const { return flags[IsFloating]; } 211 212 bool isControl() const { return flags[IsControl]; } 213 bool isCall() const { return flags[IsCall]; } 214 bool isReturn() const { return flags[IsReturn]; } 215 bool isDirectCtrl() const { return flags[IsDirectControl]; } 216 bool isIndirectCtrl() const { return flags[IsIndirectControl]; } 217 bool isCondCtrl() const { return flags[IsCondControl]; } 218 bool isUncondCtrl() const { return flags[IsUncondControl]; } 219 220 bool isThreadSync() const { return flags[IsThreadSync]; } 221 bool isSerializing() const { return flags[IsSerializing] || 222 flags[IsSerializeBefore] || 223 flags[IsSerializeAfter]; } 224 bool isSerializeBefore() const { return flags[IsSerializeBefore]; } 225 bool isSerializeAfter() const { return flags[IsSerializeAfter]; } 226 bool isMemBarrier() const { return flags[IsMemBarrier]; } 227 bool isWriteBarrier() const { return flags[IsWriteBarrier]; } 228 bool isNonSpeculative() const { return flags[IsNonSpeculative]; } 229 bool isQuiesce() const { return flags[IsQuiesce]; } 230 bool isIprAccess() const { return flags[IsIprAccess]; } 231 bool isUnverifiable() const { return flags[IsUnverifiable]; } 232 //@} 233 234 /// Operation class. Used to select appropriate function unit in issue. 235 OpClass opClass() const { return _opClass; } 236}; 237 238 239// forward declaration 240class StaticInstPtr; 241 242/** 243 * Generic yet ISA-dependent static instruction class. 244 * 245 * This class builds on StaticInstBase, defining fields and interfaces 246 * that are generic across all ISAs but that differ in details 247 * according to the specific ISA being used. 248 */ 249class StaticInst : public StaticInstBase 250{ 251 public: 252 253 /// Binary machine instruction type. 254 typedef TheISA::MachInst MachInst; 255 /// Binary extended machine instruction type. 256 typedef TheISA::ExtMachInst ExtMachInst; 257 /// Logical register index type. 258 typedef TheISA::RegIndex RegIndex; 259 260 enum { 261 MaxInstSrcRegs = TheISA::MaxInstSrcRegs, //< Max source regs 262 MaxInstDestRegs = TheISA::MaxInstDestRegs, //< Max dest regs 263 }; 264 265 266 /// Return logical index (architectural reg num) of i'th destination reg. 267 /// Only the entries from 0 through numDestRegs()-1 are valid. 268 RegIndex destRegIdx(int i) const { return _destRegIdx[i]; } 269 270 /// Return logical index (architectural reg num) of i'th source reg. 271 /// Only the entries from 0 through numSrcRegs()-1 are valid. 272 RegIndex srcRegIdx(int i) const { return _srcRegIdx[i]; } 273 274 /// Pointer to a statically allocated "null" instruction object. 275 /// Used to give eaCompInst() and memAccInst() something to return 276 /// when called on non-memory instructions. 277 static StaticInstPtr nullStaticInstPtr; 278 279 /** 280 * Memory references only: returns "fake" instruction representing 281 * the effective address part of the memory operation. Used to 282 * obtain the dependence info (numSrcRegs and srcRegIdx[]) for 283 * just the EA computation. 284 */ 285 virtual const 286 StaticInstPtr &eaCompInst() const { return nullStaticInstPtr; } 287 288 /** 289 * Memory references only: returns "fake" instruction representing 290 * the memory access part of the memory operation. Used to 291 * obtain the dependence info (numSrcRegs and srcRegIdx[]) for 292 * just the memory access (not the EA computation). 293 */ 294 virtual const 295 StaticInstPtr &memAccInst() const { return nullStaticInstPtr; } 296 297 /// The binary machine instruction. 298 const ExtMachInst machInst; 299 300 protected: 301 302 /// See destRegIdx(). 303 RegIndex _destRegIdx[MaxInstDestRegs]; 304 /// See srcRegIdx(). 305 RegIndex _srcRegIdx[MaxInstSrcRegs]; 306 307 /** 308 * Base mnemonic (e.g., "add"). Used by generateDisassembly() 309 * methods. Also useful to readily identify instructions from 310 * within the debugger when #cachedDisassembly has not been 311 * initialized. 312 */ 313 const char *mnemonic; 314 315 /** 316 * String representation of disassembly (lazily evaluated via 317 * disassemble()). 318 */ 319 mutable std::string *cachedDisassembly; 320 321 /** 322 * Internal function to generate disassembly string. 323 */ 324 virtual std::string 325 generateDisassembly(Addr pc, const SymbolTable *symtab) const = 0; 326 327 /// Constructor. 328 StaticInst(const char *_mnemonic, ExtMachInst _machInst, OpClass __opClass) 329 : StaticInstBase(__opClass), 330 machInst(_machInst), mnemonic(_mnemonic), cachedDisassembly(0) 331 { 332 } 333 334 public: 335 336 virtual ~StaticInst() 337 { 338 if (cachedDisassembly) 339 delete cachedDisassembly; 340 } 341 342/** 343 * The execute() signatures are auto-generated by scons based on the 344 * set of CPU models we are compiling in today. 345 */ 346#include "cpu/static_inst_exec_sigs.hh" 347 348 /** 349 * Return the target address for a PC-relative branch. 350 * Invalid if not a PC-relative branch (i.e. isDirectCtrl() 351 * should be true). 352 */ 353 virtual Addr branchTarget(Addr branchPC) const 354 { 355 panic("StaticInst::branchTarget() called on instruction " 356 "that is not a PC-relative branch."); 357 } 358 359 /** 360 * Return the target address for an indirect branch (jump). The 361 * register value is read from the supplied thread context, so 362 * the result is valid only if the thread context is about to 363 * execute the branch in question. Invalid if not an indirect 364 * branch (i.e. isIndirectCtrl() should be true). 365 */ 366 virtual Addr branchTarget(ThreadContext *tc) const 367 { 368 panic("StaticInst::branchTarget() called on instruction " 369 "that is not an indirect branch."); 370 } 371 372 /** 373 * Return true if the instruction is a control transfer, and if so, 374 * return the target address as well. 375 */ 376 bool hasBranchTarget(Addr pc, ThreadContext *tc, Addr &tgt) const; 377 378 /** 379 * Return string representation of disassembled instruction. 380 * The default version of this function will call the internal 381 * virtual generateDisassembly() function to get the string, 382 * then cache it in #cachedDisassembly. If the disassembly 383 * should not be cached, this function should be overridden directly. 384 */ 385 virtual const std::string &disassemble(Addr pc, 386 const SymbolTable *symtab = 0) const 387 { 388 if (!cachedDisassembly) 389 cachedDisassembly = 390 new std::string(generateDisassembly(pc, symtab)); 391 392 return *cachedDisassembly; 393 } 394 395 /// Decoded instruction cache type. 396 /// For now we're using a generic hash_map; this seems to work 397 /// pretty well. 398 typedef m5::hash_map<ExtMachInst, StaticInstPtr> DecodeCache; 399 400 /// A cache of decoded instruction objects. 401 static DecodeCache decodeCache; 402 403 /** 404 * Dump some basic stats on the decode cache hash map. 405 * Only gets called if DECODE_CACHE_HASH_STATS is defined. 406 */ 407 static void dumpDecodeCacheStats(); 408 409 /// Decode a machine instruction. 410 /// @param mach_inst The binary instruction to decode. 411 /// @retval A pointer to the corresponding StaticInst object. 412 //This is defined as inline below. 413 static StaticInstPtr decode(ExtMachInst mach_inst); 414 415 /// Return opcode of machine instruction 416 uint32_t getOpcode() { return bits(machInst, 31, 26);} 417 418 /// Return name of machine instruction 419 std::string getName() { return mnemonic; } 420}; 421 422typedef RefCountingPtr<StaticInstBase> StaticInstBasePtr; 423 424/// Reference-counted pointer to a StaticInst object. 425/// This type should be used instead of "StaticInst *" so that 426/// StaticInst objects can be properly reference-counted. 427class StaticInstPtr : public RefCountingPtr<StaticInst> 428{ 429 public: 430 /// Constructor. 431 StaticInstPtr() 432 : RefCountingPtr<StaticInst>() 433 { 434 } 435 436 /// Conversion from "StaticInst *". 437 StaticInstPtr(StaticInst *p) 438 : RefCountingPtr<StaticInst>(p) 439 { 440 } 441 442 /// Copy constructor. 443 StaticInstPtr(const StaticInstPtr &r) 444 : RefCountingPtr<StaticInst>(r) 445 { 446 } 447 448 /// Construct directly from machine instruction. 449 /// Calls StaticInst::decode(). 450 StaticInstPtr(TheISA::ExtMachInst mach_inst) 451 : RefCountingPtr<StaticInst>(StaticInst::decode(mach_inst)) 452 { 453 } 454 455 /// Convert to pointer to StaticInstBase class. 456 operator const StaticInstBasePtr() 457 { 458 return this->get(); 459 } 460}; 461 462inline StaticInstPtr 463StaticInst::decode(StaticInst::ExtMachInst mach_inst) 464{ 465#ifdef DECODE_CACHE_HASH_STATS 466 // Simple stats on decode hash_map. Turns out the default 467 // hash function is as good as anything I could come up with. 468 const int dump_every_n = 10000000; 469 static int decodes_til_dump = dump_every_n; 470 471 if (--decodes_til_dump == 0) { 472 dumpDecodeCacheStats(); 473 decodes_til_dump = dump_every_n; 474 } 475#endif 476 477 DecodeCache::iterator iter = decodeCache.find(mach_inst); 478 if (iter != decodeCache.end()) { 479 return iter->second; 480 } 481 482 StaticInstPtr si = TheISA::decodeInst(mach_inst); 483 decodeCache[mach_inst] = si; 484 return si; 485} 486 487#endif // __CPU_STATIC_INST_HH__ 488