static_inst.hh revision 2107
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 29#ifndef __CPU_STATIC_INST_HH__ 30#define __CPU_STATIC_INST_HH__ 31 32#include <bitset> 33#include <string> 34 35#include "base/hashmap.hh" 36#include "base/refcnt.hh" 37#include "encumbered/cpu/full/op_class.hh" 38#include "sim/host.hh" 39#include "arch/isa_traits.hh" 40 41// forward declarations 42struct AlphaSimpleImpl; 43class ExecContext; 44class DynInst; 45 46template <class Impl> 47class AlphaDynInst; 48 49class FastCPU; 50class SimpleCPU; 51class InorderCPU; 52class SymbolTable; 53 54namespace Trace { 55 class InstRecord; 56} 57 58/** 59 * Base, ISA-independent static instruction class. 60 * 61 * The main component of this class is the vector of flags and the 62 * associated methods for reading them. Any object that can rely 63 * solely on these flags can process instructions without being 64 * recompiled for multiple ISAs. 65 */ 66class StaticInstBase : public RefCounted 67{ 68 protected: 69 70 /// Set of boolean static instruction properties. 71 /// 72 /// Notes: 73 /// - The IsInteger and IsFloating flags are based on the class of 74 /// registers accessed by the instruction. Although most 75 /// instructions will have exactly one of these two flags set, it 76 /// is possible for an instruction to have neither (e.g., direct 77 /// unconditional branches, memory barriers) or both (e.g., an 78 /// FP/int conversion). 79 /// - If IsMemRef is set, then exactly one of IsLoad or IsStore 80 /// will be set. 81 /// - If IsControl is set, then exactly one of IsDirectControl or 82 /// IsIndirect Control will be set, and exactly one of 83 /// IsCondControl or IsUncondControl will be set. 84 /// - IsSerializing, IsMemBarrier, and IsWriteBarrier are 85 /// implemented as flags since in the current model there's no 86 /// other way for instructions to inject behavior into the 87 /// pipeline outside of fetch. Once we go to an exec-in-exec CPU 88 /// model we should be able to get rid of these flags and 89 /// implement this behavior via the execute() methods. 90 /// 91 enum Flags { 92 IsNop, ///< Is a no-op (no effect at all). 93 94 IsInteger, ///< References integer regs. 95 IsFloating, ///< References FP regs. 96 97 IsMemRef, ///< References memory (load, store, or prefetch). 98 IsLoad, ///< Reads from memory (load or prefetch). 99 IsStore, ///< Writes to memory. 100 IsInstPrefetch, ///< Instruction-cache prefetch. 101 IsDataPrefetch, ///< Data-cache prefetch. 102 IsCopy, ///< Fast Cache block copy 103 104 IsControl, ///< Control transfer instruction. 105 IsDirectControl, ///< PC relative control transfer. 106 IsIndirectControl, ///< Register indirect control transfer. 107 IsCondControl, ///< Conditional control transfer. 108 IsUncondControl, ///< Unconditional control transfer. 109 IsCall, ///< Subroutine call. 110 IsReturn, ///< Subroutine return. 111 112 IsThreadSync, ///< Thread synchronization operation. 113 114 IsSerializing, ///< Serializes pipeline: won't execute until all 115 /// older instructions have committed. 116 IsMemBarrier, ///< Is a memory barrier 117 IsWriteBarrier, ///< Is a write barrier 118 119 IsNonSpeculative, ///< Should not be executed speculatively 120 121 NumFlags 122 }; 123 124 /// Flag values for this instruction. 125 std::bitset<NumFlags> flags; 126 127 /// See opClass(). 128 OpClass _opClass; 129 130 /// See numSrcRegs(). 131 int8_t _numSrcRegs; 132 133 /// See numDestRegs(). 134 int8_t _numDestRegs; 135 136 /// The following are used to track physical register usage 137 /// for machines with separate int & FP reg files. 138 //@{ 139 int8_t _numFPDestRegs; 140 int8_t _numIntDestRegs; 141 //@} 142 143 /// Constructor. 144 /// It's important to initialize everything here to a sane 145 /// default, since the decoder generally only overrides 146 /// the fields that are meaningful for the particular 147 /// instruction. 148 StaticInstBase(OpClass __opClass) 149 : _opClass(__opClass), _numSrcRegs(0), _numDestRegs(0), 150 _numFPDestRegs(0), _numIntDestRegs(0) 151 { 152 } 153 154 public: 155 156 /// @name Register information. 157 /// The sum of numFPDestRegs() and numIntDestRegs() equals 158 /// numDestRegs(). The former two functions are used to track 159 /// physical register usage for machines with separate int & FP 160 /// reg files. 161 //@{ 162 /// Number of source registers. 163 int8_t numSrcRegs() const { return _numSrcRegs; } 164 /// Number of destination registers. 165 int8_t numDestRegs() const { return _numDestRegs; } 166 /// Number of floating-point destination regs. 167 int8_t numFPDestRegs() const { return _numFPDestRegs; } 168 /// Number of integer destination regs. 169 int8_t numIntDestRegs() const { return _numIntDestRegs; } 170 //@} 171 172 /// @name Flag accessors. 173 /// These functions are used to access the values of the various 174 /// instruction property flags. See StaticInstBase::Flags for descriptions 175 /// of the individual flags. 176 //@{ 177 178 bool isNop() const { return flags[IsNop]; } 179 180 bool isMemRef() const { return flags[IsMemRef]; } 181 bool isLoad() const { return flags[IsLoad]; } 182 bool isStore() const { return flags[IsStore]; } 183 bool isInstPrefetch() const { return flags[IsInstPrefetch]; } 184 bool isDataPrefetch() const { return flags[IsDataPrefetch]; } 185 bool isCopy() const { return flags[IsCopy];} 186 187 bool isInteger() const { return flags[IsInteger]; } 188 bool isFloating() const { return flags[IsFloating]; } 189 190 bool isControl() const { return flags[IsControl]; } 191 bool isCall() const { return flags[IsCall]; } 192 bool isReturn() const { return flags[IsReturn]; } 193 bool isDirectCtrl() const { return flags[IsDirectControl]; } 194 bool isIndirectCtrl() const { return flags[IsIndirectControl]; } 195 bool isCondCtrl() const { return flags[IsCondControl]; } 196 bool isUncondCtrl() const { return flags[IsUncondControl]; } 197 198 bool isThreadSync() const { return flags[IsThreadSync]; } 199 bool isSerializing() const { return flags[IsSerializing]; } 200 bool isMemBarrier() const { return flags[IsMemBarrier]; } 201 bool isWriteBarrier() const { return flags[IsWriteBarrier]; } 202 bool isNonSpeculative() const { return flags[IsNonSpeculative]; } 203 //@} 204 205 /// Operation class. Used to select appropriate function unit in issue. 206 OpClass opClass() const { return _opClass; } 207}; 208 209 210// forward declaration 211class StaticInstPtr; 212 213/** 214 * Generic yet ISA-dependent static instruction class. 215 * 216 * This class builds on StaticInstBase, defining fields and interfaces 217 * that are generic across all ISAs but that differ in details 218 * according to the specific ISA being used. 219 */ 220class StaticInst : public StaticInstBase 221{ 222 public: 223 224 /// Binary machine instruction type. 225 typedef TheISA::MachInst MachInst; 226 /// Memory address type. 227 typedef TheISA::Addr Addr; 228 /// Logical register index type. 229 typedef TheISA::RegIndex RegIndex; 230 231 enum { 232 MaxInstSrcRegs = TheISA::MaxInstSrcRegs, //< Max source regs 233 MaxInstDestRegs = TheISA::MaxInstDestRegs, //< Max dest regs 234 }; 235 236 237 /// Return logical index (architectural reg num) of i'th destination reg. 238 /// Only the entries from 0 through numDestRegs()-1 are valid. 239 RegIndex destRegIdx(int i) const { return _destRegIdx[i]; } 240 241 /// Return logical index (architectural reg num) of i'th source reg. 242 /// Only the entries from 0 through numSrcRegs()-1 are valid. 243 RegIndex srcRegIdx(int i) const { return _srcRegIdx[i]; } 244 245 /// Pointer to a statically allocated "null" instruction object. 246 /// Used to give eaCompInst() and memAccInst() something to return 247 /// when called on non-memory instructions. 248 static StaticInstPtr nullStaticInstPtr; 249 250 /** 251 * Memory references only: returns "fake" instruction representing 252 * the effective address part of the memory operation. Used to 253 * obtain the dependence info (numSrcRegs and srcRegIdx[]) for 254 * just the EA computation. 255 */ 256 virtual const 257 StaticInstPtr &eaCompInst() const { return nullStaticInstPtr; } 258 259 /** 260 * Memory references only: returns "fake" instruction representing 261 * the memory access part of the memory operation. Used to 262 * obtain the dependence info (numSrcRegs and srcRegIdx[]) for 263 * just the memory access (not the EA computation). 264 */ 265 virtual const 266 StaticInstPtr &memAccInst() const { return nullStaticInstPtr; } 267 268 /// The binary machine instruction. 269 const MachInst machInst; 270 271 protected: 272 273 /// See destRegIdx(). 274 RegIndex _destRegIdx[MaxInstDestRegs]; 275 /// See srcRegIdx(). 276 RegIndex _srcRegIdx[MaxInstSrcRegs]; 277 278 /** 279 * Base mnemonic (e.g., "add"). Used by generateDisassembly() 280 * methods. Also useful to readily identify instructions from 281 * within the debugger when #cachedDisassembly has not been 282 * initialized. 283 */ 284 const char *mnemonic; 285 286 /** 287 * String representation of disassembly (lazily evaluated via 288 * disassemble()). 289 */ 290 mutable std::string *cachedDisassembly; 291 292 /** 293 * Internal function to generate disassembly string. 294 */ 295 virtual std::string 296 generateDisassembly(Addr pc, const SymbolTable *symtab) const = 0; 297 298 /// Constructor. 299 StaticInst(const char *_mnemonic, MachInst _machInst, OpClass __opClass) 300 : StaticInstBase(__opClass), 301 machInst(_machInst), mnemonic(_mnemonic), cachedDisassembly(0) 302 { 303 } 304 305 public: 306 307 virtual ~StaticInst() 308 { 309 if (cachedDisassembly) 310 delete cachedDisassembly; 311 } 312 313#include "static_inst_impl.hh" 314 315 /** 316 * Return the target address for a PC-relative branch. 317 * Invalid if not a PC-relative branch (i.e. isDirectCtrl() 318 * should be true). 319 */ 320 virtual Addr branchTarget(Addr branchPC) const 321 { 322 panic("StaticInst::branchTarget() called on instruction " 323 "that is not a PC-relative branch."); 324 } 325 326 /** 327 * Return the target address for an indirect branch (jump). The 328 * register value is read from the supplied execution context, so 329 * the result is valid only if the execution context is about to 330 * execute the branch in question. Invalid if not an indirect 331 * branch (i.e. isIndirectCtrl() should be true). 332 */ 333 virtual Addr branchTarget(ExecContext *xc) const 334 { 335 panic("StaticInst::branchTarget() called on instruction " 336 "that is not an indirect branch."); 337 } 338 339 /** 340 * Return true if the instruction is a control transfer, and if so, 341 * return the target address as well. 342 */ 343 bool hasBranchTarget(Addr pc, ExecContext *xc, Addr &tgt) const; 344 345 /** 346 * Return string representation of disassembled instruction. 347 * The default version of this function will call the internal 348 * virtual generateDisassembly() function to get the string, 349 * then cache it in #cachedDisassembly. If the disassembly 350 * should not be cached, this function should be overridden directly. 351 */ 352 virtual const std::string &disassemble(Addr pc, 353 const SymbolTable *symtab = 0) const 354 { 355 if (!cachedDisassembly) 356 cachedDisassembly = 357 new std::string(generateDisassembly(pc, symtab)); 358 359 return *cachedDisassembly; 360 } 361 362 /// Decoded instruction cache type. 363 /// For now we're using a generic hash_map; this seems to work 364 /// pretty well. 365 typedef m5::hash_map<MachInst, StaticInstPtr> DecodeCache; 366 367 /// A cache of decoded instruction objects. 368 static DecodeCache decodeCache; 369 370 /** 371 * Dump some basic stats on the decode cache hash map. 372 * Only gets called if DECODE_CACHE_HASH_STATS is defined. 373 */ 374 static void dumpDecodeCacheStats(); 375 376 /// Decode a machine instruction. 377 /// @param mach_inst The binary instruction to decode. 378 /// @retval A pointer to the corresponding StaticInst object. 379 //This is defined as inline below. 380 static StaticInstPtr decode(MachInst mach_inst); 381}; 382 383typedef RefCountingPtr<StaticInstBase> StaticInstBasePtr; 384 385/// Reference-counted pointer to a StaticInst object. 386/// This type should be used instead of "StaticInst *" so that 387/// StaticInst objects can be properly reference-counted. 388class StaticInstPtr : public RefCountingPtr<StaticInst> 389{ 390 public: 391 /// Constructor. 392 StaticInstPtr() 393 : RefCountingPtr<StaticInst>() 394 { 395 } 396 397 /// Conversion from "StaticInst *". 398 StaticInstPtr(StaticInst *p) 399 : RefCountingPtr<StaticInst>(p) 400 { 401 } 402 403 /// Copy constructor. 404 StaticInstPtr(const StaticInstPtr &r) 405 : RefCountingPtr<StaticInst>(r) 406 { 407 } 408 409 /// Construct directly from machine instruction. 410 /// Calls StaticInst::decode(). 411 StaticInstPtr(TheISA::MachInst mach_inst) 412 : RefCountingPtr<StaticInst>(StaticInst::decode(mach_inst)) 413 { 414 } 415 416 /// Convert to pointer to StaticInstBase class. 417 operator const StaticInstBasePtr() 418 { 419 return this->get(); 420 } 421}; 422 423inline StaticInstPtr 424StaticInst::decode(StaticInst::MachInst mach_inst) 425{ 426#ifdef DECODE_CACHE_HASH_STATS 427 // Simple stats on decode hash_map. Turns out the default 428 // hash function is as good as anything I could come up with. 429 const int dump_every_n = 10000000; 430 static int decodes_til_dump = dump_every_n; 431 432 if (--decodes_til_dump == 0) { 433 dumpDecodeCacheStats(); 434 decodes_til_dump = dump_every_n; 435 } 436#endif 437 438 DecodeCache::iterator iter = decodeCache.find(mach_inst); 439 if (iter != decodeCache.end()) { 440 return iter->second; 441 } 442 443 StaticInstPtr si = TheISA::decodeInst(mach_inst); 444 decodeCache[mach_inst] = si; 445 return si; 446} 447 448#endif // __CPU_STATIC_INST_HH__ 449