JITEmitter.cpp revision 2d274412ed9aab277e070690c574714ec544cf94
1//===-- JITEmitter.cpp - Write machine code to executable memory ----------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines a MachineCodeEmitter object that is used by the JIT to 11// write machine code to memory and remember where relocatable values are. 12// 13//===----------------------------------------------------------------------===// 14 15#define DEBUG_TYPE "jit" 16#include "JIT.h" 17#include "JITDebugRegisterer.h" 18#include "JITDwarfEmitter.h" 19#include "llvm/ADT/OwningPtr.h" 20#include "llvm/Constants.h" 21#include "llvm/Module.h" 22#include "llvm/DerivedTypes.h" 23#include "llvm/CodeGen/JITCodeEmitter.h" 24#include "llvm/CodeGen/MachineFunction.h" 25#include "llvm/CodeGen/MachineConstantPool.h" 26#include "llvm/CodeGen/MachineJumpTableInfo.h" 27#include "llvm/CodeGen/MachineModuleInfo.h" 28#include "llvm/CodeGen/MachineRelocation.h" 29#include "llvm/ExecutionEngine/GenericValue.h" 30#include "llvm/ExecutionEngine/JITEventListener.h" 31#include "llvm/ExecutionEngine/JITMemoryManager.h" 32#include "llvm/CodeGen/MachineCodeInfo.h" 33#include "llvm/Target/TargetData.h" 34#include "llvm/Target/TargetJITInfo.h" 35#include "llvm/Target/TargetMachine.h" 36#include "llvm/Target/TargetOptions.h" 37#include "llvm/Support/Debug.h" 38#include "llvm/Support/ErrorHandling.h" 39#include "llvm/Support/MutexGuard.h" 40#include "llvm/Support/ValueHandle.h" 41#include "llvm/Support/raw_ostream.h" 42#include "llvm/System/Disassembler.h" 43#include "llvm/System/Memory.h" 44#include "llvm/Target/TargetInstrInfo.h" 45#include "llvm/ADT/DenseMap.h" 46#include "llvm/ADT/SmallPtrSet.h" 47#include "llvm/ADT/SmallVector.h" 48#include "llvm/ADT/Statistic.h" 49#include "llvm/ADT/ValueMap.h" 50#include <algorithm> 51#ifndef NDEBUG 52#include <iomanip> 53#endif 54using namespace llvm; 55 56STATISTIC(NumBytes, "Number of bytes of machine code compiled"); 57STATISTIC(NumRelos, "Number of relocations applied"); 58STATISTIC(NumRetries, "Number of retries with more memory"); 59static JIT *TheJIT = 0; 60 61 62//===----------------------------------------------------------------------===// 63// JIT lazy compilation code. 64// 65namespace { 66 class JITEmitter; 67 class JITResolverState; 68 69 template<typename ValueTy> 70 struct NoRAUWValueMapConfig : public ValueMapConfig<ValueTy> { 71 typedef JITResolverState *ExtraData; 72 static void onRAUW(JITResolverState *, Value *Old, Value *New) { 73 assert(false && "The JIT doesn't know how to handle a" 74 " RAUW on a value it has emitted."); 75 } 76 }; 77 78 struct CallSiteValueMapConfig : public NoRAUWValueMapConfig<Function*> { 79 typedef JITResolverState *ExtraData; 80 static void onDelete(JITResolverState *JRS, Function *F); 81 }; 82 83 class JITResolverState { 84 public: 85 typedef ValueMap<Function*, void*, NoRAUWValueMapConfig<Function*> > 86 FunctionToStubMapTy; 87 typedef std::map<void*, AssertingVH<Function> > CallSiteToFunctionMapTy; 88 typedef ValueMap<Function *, SmallPtrSet<void*, 1>, 89 CallSiteValueMapConfig> FunctionToCallSitesMapTy; 90 typedef std::map<AssertingVH<GlobalValue>, void*> GlobalToIndirectSymMapTy; 91 private: 92 /// FunctionToStubMap - Keep track of the stub created for a particular 93 /// function so that we can reuse them if necessary. 94 FunctionToStubMapTy FunctionToStubMap; 95 96 /// CallSiteToFunctionMap - Keep track of the function that each lazy call 97 /// site corresponds to, and vice versa. 98 CallSiteToFunctionMapTy CallSiteToFunctionMap; 99 FunctionToCallSitesMapTy FunctionToCallSitesMap; 100 101 /// GlobalToIndirectSymMap - Keep track of the indirect symbol created for a 102 /// particular GlobalVariable so that we can reuse them if necessary. 103 GlobalToIndirectSymMapTy GlobalToIndirectSymMap; 104 105 public: 106 JITResolverState() : FunctionToStubMap(this), 107 FunctionToCallSitesMap(this) {} 108 109 FunctionToStubMapTy& getFunctionToStubMap(const MutexGuard& locked) { 110 assert(locked.holds(TheJIT->lock)); 111 return FunctionToStubMap; 112 } 113 114 GlobalToIndirectSymMapTy& getGlobalToIndirectSymMap(const MutexGuard& locked) { 115 assert(locked.holds(TheJIT->lock)); 116 return GlobalToIndirectSymMap; 117 } 118 119 pair<void *, Function *> LookupFunctionFromCallSite( 120 const MutexGuard &locked, void *CallSite) const { 121 assert(locked.holds(TheJIT->lock)); 122 123 // The address given to us for the stub may not be exactly right, it might be 124 // a little bit after the stub. As such, use upper_bound to find it. 125 CallSiteToFunctionMapTy::const_iterator I = 126 CallSiteToFunctionMap.upper_bound(CallSite); 127 assert(I != CallSiteToFunctionMap.begin() && 128 "This is not a known call site!"); 129 --I; 130 return *I; 131 } 132 133 void AddCallSite(const MutexGuard &locked, void *CallSite, Function *F) { 134 assert(locked.holds(TheJIT->lock)); 135 136 bool Inserted = CallSiteToFunctionMap.insert( 137 std::make_pair(CallSite, F)).second; 138 (void)Inserted; 139 assert(Inserted && "Pair was already in CallSiteToFunctionMap"); 140 FunctionToCallSitesMap[F].insert(CallSite); 141 } 142 143 // Returns the Function of the stub if a stub was erased, or NULL if there 144 // was no stub. This function uses the call-site->function map to find a 145 // relevant function, but asserts that only stubs and not other call sites 146 // will be passed in. 147 Function *EraseStub(const MutexGuard &locked, void *Stub) { 148 CallSiteToFunctionMapTy::iterator C2F_I = 149 CallSiteToFunctionMap.find(Stub); 150 if (C2F_I == CallSiteToFunctionMap.end()) { 151 // Not a stub. 152 return NULL; 153 } 154 155 Function *const F = C2F_I->second; 156#ifndef NDEBUG 157 void *RealStub = FunctionToStubMap.lookup(F); 158 assert(RealStub == Stub && 159 "Call-site that wasn't a stub pass in to EraseStub"); 160#endif 161 FunctionToStubMap.erase(F); 162 CallSiteToFunctionMap.erase(C2F_I); 163 164 // Remove the stub from the function->call-sites map, and remove the whole 165 // entry from the map if that was the last call site. 166 FunctionToCallSitesMapTy::iterator F2C_I = FunctionToCallSitesMap.find(F); 167 assert(F2C_I != FunctionToCallSitesMap.end() && 168 "FunctionToCallSitesMap broken"); 169 bool Erased = F2C_I->second.erase(Stub); 170 (void)Erased; 171 assert(Erased && "FunctionToCallSitesMap broken"); 172 if (F2C_I->second.empty()) 173 FunctionToCallSitesMap.erase(F2C_I); 174 175 return F; 176 } 177 178 void EraseAllCallSites(const MutexGuard &locked, Function *F) { 179 assert(locked.holds(TheJIT->lock)); 180 EraseAllCallSitesPrelocked(F); 181 } 182 void EraseAllCallSitesPrelocked(Function *F) { 183 FunctionToCallSitesMapTy::iterator F2C = FunctionToCallSitesMap.find(F); 184 if (F2C == FunctionToCallSitesMap.end()) 185 return; 186 for (SmallPtrSet<void*, 1>::const_iterator I = F2C->second.begin(), 187 E = F2C->second.end(); I != E; ++I) { 188 bool Erased = CallSiteToFunctionMap.erase(*I); 189 (void)Erased; 190 assert(Erased && "Missing call site->function mapping"); 191 } 192 FunctionToCallSitesMap.erase(F2C); 193 } 194 }; 195 196 /// JITResolver - Keep track of, and resolve, call sites for functions that 197 /// have not yet been compiled. 198 class JITResolver { 199 typedef JITResolverState::FunctionToStubMapTy FunctionToStubMapTy; 200 typedef JITResolverState::CallSiteToFunctionMapTy CallSiteToFunctionMapTy; 201 typedef JITResolverState::GlobalToIndirectSymMapTy GlobalToIndirectSymMapTy; 202 203 /// LazyResolverFn - The target lazy resolver function that we actually 204 /// rewrite instructions to use. 205 TargetJITInfo::LazyResolverFn LazyResolverFn; 206 207 JITResolverState state; 208 209 /// ExternalFnToStubMap - This is the equivalent of FunctionToStubMap for 210 /// external functions. 211 std::map<void*, void*> ExternalFnToStubMap; 212 213 /// revGOTMap - map addresses to indexes in the GOT 214 std::map<void*, unsigned> revGOTMap; 215 unsigned nextGOTIndex; 216 217 JITEmitter &JE; 218 219 static JITResolver *TheJITResolver; 220 public: 221 explicit JITResolver(JIT &jit, JITEmitter &je) : nextGOTIndex(0), JE(je) { 222 TheJIT = &jit; 223 224 LazyResolverFn = jit.getJITInfo().getLazyResolverFunction(JITCompilerFn); 225 assert(TheJITResolver == 0 && "Multiple JIT resolvers?"); 226 TheJITResolver = this; 227 } 228 229 ~JITResolver() { 230 TheJITResolver = 0; 231 } 232 233 /// getFunctionStubIfAvailable - This returns a pointer to a function stub 234 /// if it has already been created. 235 void *getFunctionStubIfAvailable(Function *F); 236 237 /// getFunctionStub - This returns a pointer to a function stub, creating 238 /// one on demand as needed. If empty is true, create a function stub 239 /// pointing at address 0, to be filled in later. 240 void *getFunctionStub(Function *F); 241 242 /// getExternalFunctionStub - Return a stub for the function at the 243 /// specified address, created lazily on demand. 244 void *getExternalFunctionStub(void *FnAddr); 245 246 /// getGlobalValueIndirectSym - Return an indirect symbol containing the 247 /// specified GV address. 248 void *getGlobalValueIndirectSym(GlobalValue *V, void *GVAddress); 249 250 /// AddCallbackAtLocation - If the target is capable of rewriting an 251 /// instruction without the use of a stub, record the location of the use so 252 /// we know which function is being used at the location. 253 void *AddCallbackAtLocation(Function *F, void *Location) { 254 MutexGuard locked(TheJIT->lock); 255 /// Get the target-specific JIT resolver function. 256 state.AddCallSite(locked, Location, F); 257 return (void*)(intptr_t)LazyResolverFn; 258 } 259 260 void getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs, 261 SmallVectorImpl<void*> &Ptrs); 262 263 GlobalValue *invalidateStub(void *Stub); 264 265 /// getGOTIndexForAddress - Return a new or existing index in the GOT for 266 /// an address. This function only manages slots, it does not manage the 267 /// contents of the slots or the memory associated with the GOT. 268 unsigned getGOTIndexForAddr(void *addr); 269 270 /// JITCompilerFn - This function is called to resolve a stub to a compiled 271 /// address. If the LLVM Function corresponding to the stub has not yet 272 /// been compiled, this function compiles it first. 273 static void *JITCompilerFn(void *Stub); 274 }; 275 276 /// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is 277 /// used to output functions to memory for execution. 278 class JITEmitter : public JITCodeEmitter { 279 JITMemoryManager *MemMgr; 280 281 // When outputting a function stub in the context of some other function, we 282 // save BufferBegin/BufferEnd/CurBufferPtr here. 283 uint8_t *SavedBufferBegin, *SavedBufferEnd, *SavedCurBufferPtr; 284 285 // When reattempting to JIT a function after running out of space, we store 286 // the estimated size of the function we're trying to JIT here, so we can 287 // ask the memory manager for at least this much space. When we 288 // successfully emit the function, we reset this back to zero. 289 uintptr_t SizeEstimate; 290 291 /// Relocations - These are the relocations that the function needs, as 292 /// emitted. 293 std::vector<MachineRelocation> Relocations; 294 295 /// MBBLocations - This vector is a mapping from MBB ID's to their address. 296 /// It is filled in by the StartMachineBasicBlock callback and queried by 297 /// the getMachineBasicBlockAddress callback. 298 std::vector<uintptr_t> MBBLocations; 299 300 /// ConstantPool - The constant pool for the current function. 301 /// 302 MachineConstantPool *ConstantPool; 303 304 /// ConstantPoolBase - A pointer to the first entry in the constant pool. 305 /// 306 void *ConstantPoolBase; 307 308 /// ConstPoolAddresses - Addresses of individual constant pool entries. 309 /// 310 SmallVector<uintptr_t, 8> ConstPoolAddresses; 311 312 /// JumpTable - The jump tables for the current function. 313 /// 314 MachineJumpTableInfo *JumpTable; 315 316 /// JumpTableBase - A pointer to the first entry in the jump table. 317 /// 318 void *JumpTableBase; 319 320 /// Resolver - This contains info about the currently resolved functions. 321 JITResolver Resolver; 322 323 /// DE - The dwarf emitter for the jit. 324 OwningPtr<JITDwarfEmitter> DE; 325 326 /// DR - The debug registerer for the jit. 327 OwningPtr<JITDebugRegisterer> DR; 328 329 /// LabelLocations - This vector is a mapping from Label ID's to their 330 /// address. 331 std::vector<uintptr_t> LabelLocations; 332 333 /// MMI - Machine module info for exception informations 334 MachineModuleInfo* MMI; 335 336 // GVSet - a set to keep track of which globals have been seen 337 SmallPtrSet<const GlobalVariable*, 8> GVSet; 338 339 // CurFn - The llvm function being emitted. Only valid during 340 // finishFunction(). 341 const Function *CurFn; 342 343 /// Information about emitted code, which is passed to the 344 /// JITEventListeners. This is reset in startFunction and used in 345 /// finishFunction. 346 JITEvent_EmittedFunctionDetails EmissionDetails; 347 348 struct EmittedCode { 349 void *FunctionBody; // Beginning of the function's allocation. 350 void *Code; // The address the function's code actually starts at. 351 void *ExceptionTable; 352 EmittedCode() : FunctionBody(0), Code(0), ExceptionTable(0) {} 353 }; 354 struct EmittedFunctionConfig : public ValueMapConfig<const Function*> { 355 typedef JITEmitter *ExtraData; 356 static void onDelete(JITEmitter *, const Function*); 357 static void onRAUW(JITEmitter *, const Function*, const Function*); 358 }; 359 ValueMap<const Function *, EmittedCode, 360 EmittedFunctionConfig> EmittedFunctions; 361 362 // CurFnStubUses - For a given Function, a vector of stubs that it 363 // references. This facilitates the JIT detecting that a stub is no 364 // longer used, so that it may be deallocated. 365 DenseMap<AssertingVH<const Function>, SmallVector<void*, 1> > CurFnStubUses; 366 367 // StubFnRefs - For a given pointer to a stub, a set of Functions which 368 // reference the stub. When the count of a stub's references drops to zero, 369 // the stub is unused. 370 DenseMap<void *, SmallPtrSet<const Function*, 1> > StubFnRefs; 371 372 // ExtFnStubs - A map of external function names to stubs which have entries 373 // in the JITResolver's ExternalFnToStubMap. 374 StringMap<void *> ExtFnStubs; 375 376 DebugLocTuple PrevDLT; 377 378 public: 379 JITEmitter(JIT &jit, JITMemoryManager *JMM, TargetMachine &TM) 380 : SizeEstimate(0), Resolver(jit, *this), MMI(0), CurFn(0), 381 EmittedFunctions(this) { 382 MemMgr = JMM ? JMM : JITMemoryManager::CreateDefaultMemManager(); 383 if (jit.getJITInfo().needsGOT()) { 384 MemMgr->AllocateGOT(); 385 DEBUG(errs() << "JIT is managing a GOT\n"); 386 } 387 388 if (DwarfExceptionHandling || JITEmitDebugInfo) { 389 DE.reset(new JITDwarfEmitter(jit)); 390 } 391 if (JITEmitDebugInfo) { 392 DR.reset(new JITDebugRegisterer(TM)); 393 } 394 } 395 ~JITEmitter() { 396 delete MemMgr; 397 } 398 399 /// classof - Methods for support type inquiry through isa, cast, and 400 /// dyn_cast: 401 /// 402 static inline bool classof(const JITEmitter*) { return true; } 403 static inline bool classof(const MachineCodeEmitter*) { return true; } 404 405 JITResolver &getJITResolver() { return Resolver; } 406 407 virtual void startFunction(MachineFunction &F); 408 virtual bool finishFunction(MachineFunction &F); 409 410 void emitConstantPool(MachineConstantPool *MCP); 411 void initJumpTableInfo(MachineJumpTableInfo *MJTI); 412 void emitJumpTableInfo(MachineJumpTableInfo *MJTI); 413 414 virtual void startGVStub(const GlobalValue* GV, unsigned StubSize, 415 unsigned Alignment = 1); 416 virtual void startGVStub(const GlobalValue* GV, void *Buffer, 417 unsigned StubSize); 418 virtual void* finishGVStub(const GlobalValue *GV); 419 420 /// allocateSpace - Reserves space in the current block if any, or 421 /// allocate a new one of the given size. 422 virtual void *allocateSpace(uintptr_t Size, unsigned Alignment); 423 424 /// allocateGlobal - Allocate memory for a global. Unlike allocateSpace, 425 /// this method does not allocate memory in the current output buffer, 426 /// because a global may live longer than the current function. 427 virtual void *allocateGlobal(uintptr_t Size, unsigned Alignment); 428 429 virtual void addRelocation(const MachineRelocation &MR) { 430 Relocations.push_back(MR); 431 } 432 433 virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) { 434 if (MBBLocations.size() <= (unsigned)MBB->getNumber()) 435 MBBLocations.resize((MBB->getNumber()+1)*2); 436 MBBLocations[MBB->getNumber()] = getCurrentPCValue(); 437 DEBUG(errs() << "JIT: Emitting BB" << MBB->getNumber() << " at [" 438 << (void*) getCurrentPCValue() << "]\n"); 439 } 440 441 virtual uintptr_t getConstantPoolEntryAddress(unsigned Entry) const; 442 virtual uintptr_t getJumpTableEntryAddress(unsigned Entry) const; 443 444 virtual uintptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const { 445 assert(MBBLocations.size() > (unsigned)MBB->getNumber() && 446 MBBLocations[MBB->getNumber()] && "MBB not emitted!"); 447 return MBBLocations[MBB->getNumber()]; 448 } 449 450 /// retryWithMoreMemory - Log a retry and deallocate all memory for the 451 /// given function. Increase the minimum allocation size so that we get 452 /// more memory next time. 453 void retryWithMoreMemory(MachineFunction &F); 454 455 /// deallocateMemForFunction - Deallocate all memory for the specified 456 /// function body. 457 void deallocateMemForFunction(const Function *F); 458 459 /// AddStubToCurrentFunction - Mark the current function being JIT'd as 460 /// using the stub at the specified address. Allows 461 /// deallocateMemForFunction to also remove stubs no longer referenced. 462 void AddStubToCurrentFunction(void *Stub); 463 464 /// getExternalFnStubs - Accessor for the JIT to find stubs emitted for 465 /// MachineRelocations that reference external functions by name. 466 const StringMap<void*> &getExternalFnStubs() const { return ExtFnStubs; } 467 468 virtual void processDebugLoc(DebugLoc DL, bool BeforePrintingInsn); 469 470 virtual void emitLabel(uint64_t LabelID) { 471 if (LabelLocations.size() <= LabelID) 472 LabelLocations.resize((LabelID+1)*2); 473 LabelLocations[LabelID] = getCurrentPCValue(); 474 } 475 476 virtual uintptr_t getLabelAddress(uint64_t LabelID) const { 477 assert(LabelLocations.size() > (unsigned)LabelID && 478 LabelLocations[LabelID] && "Label not emitted!"); 479 return LabelLocations[LabelID]; 480 } 481 482 virtual void setModuleInfo(MachineModuleInfo* Info) { 483 MMI = Info; 484 if (DE.get()) DE->setModuleInfo(Info); 485 } 486 487 void setMemoryExecutable() { 488 MemMgr->setMemoryExecutable(); 489 } 490 491 JITMemoryManager *getMemMgr() const { return MemMgr; } 492 493 private: 494 void *getPointerToGlobal(GlobalValue *GV, void *Reference, 495 bool MayNeedFarStub); 496 void *getPointerToGVIndirectSym(GlobalValue *V, void *Reference); 497 unsigned addSizeOfGlobal(const GlobalVariable *GV, unsigned Size); 498 unsigned addSizeOfGlobalsInConstantVal(const Constant *C, unsigned Size); 499 unsigned addSizeOfGlobalsInInitializer(const Constant *Init, unsigned Size); 500 unsigned GetSizeOfGlobalsInBytes(MachineFunction &MF); 501 }; 502} 503 504JITResolver *JITResolver::TheJITResolver = 0; 505 506void CallSiteValueMapConfig::onDelete(JITResolverState *JRS, Function *F) { 507 JRS->EraseAllCallSitesPrelocked(F); 508} 509 510/// getFunctionStubIfAvailable - This returns a pointer to a function stub 511/// if it has already been created. 512void *JITResolver::getFunctionStubIfAvailable(Function *F) { 513 MutexGuard locked(TheJIT->lock); 514 515 // If we already have a stub for this function, recycle it. 516 return state.getFunctionToStubMap(locked).lookup(F); 517} 518 519/// getFunctionStub - This returns a pointer to a function stub, creating 520/// one on demand as needed. 521void *JITResolver::getFunctionStub(Function *F) { 522 MutexGuard locked(TheJIT->lock); 523 524 // If we already have a stub for this function, recycle it. 525 void *&Stub = state.getFunctionToStubMap(locked)[F]; 526 if (Stub) return Stub; 527 528 // Call the lazy resolver function if we are JIT'ing lazily. Otherwise we 529 // must resolve the symbol now. 530 void *Actual = TheJIT->isCompilingLazily() 531 ? (void *)(intptr_t)LazyResolverFn : (void *)0; 532 533 // If this is an external declaration, attempt to resolve the address now 534 // to place in the stub. 535 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode()) { 536 Actual = TheJIT->getPointerToFunction(F); 537 538 // If we resolved the symbol to a null address (eg. a weak external) 539 // don't emit a stub. Return a null pointer to the application. If dlsym 540 // stubs are enabled, not being able to resolve the address is not 541 // meaningful. 542 if (!Actual && !TheJIT->areDlsymStubsEnabled()) return 0; 543 } 544 545 // Codegen a new stub, calling the lazy resolver or the actual address of the 546 // external function, if it was resolved. 547 Stub = TheJIT->getJITInfo().emitFunctionStub(F, Actual, JE); 548 549 if (Actual != (void*)(intptr_t)LazyResolverFn) { 550 // If we are getting the stub for an external function, we really want the 551 // address of the stub in the GlobalAddressMap for the JIT, not the address 552 // of the external function. 553 TheJIT->updateGlobalMapping(F, Stub); 554 } 555 556 DEBUG(errs() << "JIT: Stub emitted at [" << Stub << "] for function '" 557 << F->getName() << "'\n"); 558 559 // Finally, keep track of the stub-to-Function mapping so that the 560 // JITCompilerFn knows which function to compile! 561 state.AddCallSite(locked, Stub, F); 562 563 // If we are JIT'ing non-lazily but need to call a function that does not 564 // exist yet, add it to the JIT's work list so that we can fill in the stub 565 // address later. 566 if (!Actual && !TheJIT->isCompilingLazily()) 567 if (!F->isDeclaration() || F->hasNotBeenReadFromBitcode()) 568 TheJIT->addPendingFunction(F); 569 570 return Stub; 571} 572 573/// getGlobalValueIndirectSym - Return a lazy pointer containing the specified 574/// GV address. 575void *JITResolver::getGlobalValueIndirectSym(GlobalValue *GV, void *GVAddress) { 576 MutexGuard locked(TheJIT->lock); 577 578 // If we already have a stub for this global variable, recycle it. 579 void *&IndirectSym = state.getGlobalToIndirectSymMap(locked)[GV]; 580 if (IndirectSym) return IndirectSym; 581 582 // Otherwise, codegen a new indirect symbol. 583 IndirectSym = TheJIT->getJITInfo().emitGlobalValueIndirectSym(GV, GVAddress, 584 JE); 585 586 DEBUG(errs() << "JIT: Indirect symbol emitted at [" << IndirectSym 587 << "] for GV '" << GV->getName() << "'\n"); 588 589 return IndirectSym; 590} 591 592/// getExternalFunctionStub - Return a stub for the function at the 593/// specified address, created lazily on demand. 594void *JITResolver::getExternalFunctionStub(void *FnAddr) { 595 // If we already have a stub for this function, recycle it. 596 void *&Stub = ExternalFnToStubMap[FnAddr]; 597 if (Stub) return Stub; 598 599 Stub = TheJIT->getJITInfo().emitFunctionStub(0, FnAddr, JE); 600 601 DEBUG(errs() << "JIT: Stub emitted at [" << Stub 602 << "] for external function at '" << FnAddr << "'\n"); 603 return Stub; 604} 605 606unsigned JITResolver::getGOTIndexForAddr(void* addr) { 607 unsigned idx = revGOTMap[addr]; 608 if (!idx) { 609 idx = ++nextGOTIndex; 610 revGOTMap[addr] = idx; 611 DEBUG(errs() << "JIT: Adding GOT entry " << idx << " for addr [" 612 << addr << "]\n"); 613 } 614 return idx; 615} 616 617void JITResolver::getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs, 618 SmallVectorImpl<void*> &Ptrs) { 619 MutexGuard locked(TheJIT->lock); 620 621 const FunctionToStubMapTy &FM = state.getFunctionToStubMap(locked); 622 GlobalToIndirectSymMapTy &GM = state.getGlobalToIndirectSymMap(locked); 623 624 for (FunctionToStubMapTy::const_iterator i = FM.begin(), e = FM.end(); 625 i != e; ++i){ 626 Function *F = i->first; 627 if (F->isDeclaration() && F->hasExternalLinkage()) { 628 GVs.push_back(i->first); 629 Ptrs.push_back(i->second); 630 } 631 } 632 for (GlobalToIndirectSymMapTy::iterator i = GM.begin(), e = GM.end(); 633 i != e; ++i) { 634 GVs.push_back(i->first); 635 Ptrs.push_back(i->second); 636 } 637} 638 639GlobalValue *JITResolver::invalidateStub(void *Stub) { 640 MutexGuard locked(TheJIT->lock); 641 642 GlobalToIndirectSymMapTy &GM = state.getGlobalToIndirectSymMap(locked); 643 644 // Look up the cheap way first, to see if it's a function stub we are 645 // invalidating. If so, remove it from both the forward and reverse maps. 646 if (Function *F = state.EraseStub(locked, Stub)) { 647 return F; 648 } 649 650 // Otherwise, it might be an indirect symbol stub. Find it and remove it. 651 for (GlobalToIndirectSymMapTy::iterator i = GM.begin(), e = GM.end(); 652 i != e; ++i) { 653 if (i->second != Stub) 654 continue; 655 GlobalValue *GV = i->first; 656 GM.erase(i); 657 return GV; 658 } 659 660 // Lastly, check to see if it's in the ExternalFnToStubMap. 661 for (std::map<void *, void *>::iterator i = ExternalFnToStubMap.begin(), 662 e = ExternalFnToStubMap.end(); i != e; ++i) { 663 if (i->second != Stub) 664 continue; 665 ExternalFnToStubMap.erase(i); 666 break; 667 } 668 669 return 0; 670} 671 672/// JITCompilerFn - This function is called when a lazy compilation stub has 673/// been entered. It looks up which function this stub corresponds to, compiles 674/// it if necessary, then returns the resultant function pointer. 675void *JITResolver::JITCompilerFn(void *Stub) { 676 JITResolver &JR = *TheJITResolver; 677 678 Function* F = 0; 679 void* ActualPtr = 0; 680 681 { 682 // Only lock for getting the Function. The call getPointerToFunction made 683 // in this function might trigger function materializing, which requires 684 // JIT lock to be unlocked. 685 MutexGuard locked(TheJIT->lock); 686 687 // The address given to us for the stub may not be exactly right, it might 688 // be a little bit after the stub. As such, use upper_bound to find it. 689 pair<void*, Function*> I = 690 JR.state.LookupFunctionFromCallSite(locked, Stub); 691 F = I.second; 692 ActualPtr = I.first; 693 } 694 695 // If we have already code generated the function, just return the address. 696 void *Result = TheJIT->getPointerToGlobalIfAvailable(F); 697 698 if (!Result) { 699 // Otherwise we don't have it, do lazy compilation now. 700 701 // If lazy compilation is disabled, emit a useful error message and abort. 702 if (!TheJIT->isCompilingLazily()) { 703 llvm_report_error("LLVM JIT requested to do lazy compilation of function '" 704 + F->getName() + "' when lazy compiles are disabled!"); 705 } 706 707 DEBUG(errs() << "JIT: Lazily resolving function '" << F->getName() 708 << "' In stub ptr = " << Stub << " actual ptr = " 709 << ActualPtr << "\n"); 710 711 Result = TheJIT->getPointerToFunction(F); 712 } 713 714 // Reacquire the lock to update the GOT map. 715 MutexGuard locked(TheJIT->lock); 716 717 // We might like to remove the call site from the CallSiteToFunction map, but 718 // we can't do that! Multiple threads could be stuck, waiting to acquire the 719 // lock above. As soon as the 1st function finishes compiling the function, 720 // the next one will be released, and needs to be able to find the function it 721 // needs to call. 722 723 // FIXME: We could rewrite all references to this stub if we knew them. 724 725 // What we will do is set the compiled function address to map to the 726 // same GOT entry as the stub so that later clients may update the GOT 727 // if they see it still using the stub address. 728 // Note: this is done so the Resolver doesn't have to manage GOT memory 729 // Do this without allocating map space if the target isn't using a GOT 730 if(JR.revGOTMap.find(Stub) != JR.revGOTMap.end()) 731 JR.revGOTMap[Result] = JR.revGOTMap[Stub]; 732 733 return Result; 734} 735 736//===----------------------------------------------------------------------===// 737// JITEmitter code. 738// 739void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference, 740 bool MayNeedFarStub) { 741 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) 742 return TheJIT->getOrEmitGlobalVariable(GV); 743 744 if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) 745 return TheJIT->getPointerToGlobal(GA->resolveAliasedGlobal(false)); 746 747 // If we have already compiled the function, return a pointer to its body. 748 Function *F = cast<Function>(V); 749 void *ResultPtr; 750 if (MayNeedFarStub) { 751 // Return the function stub if it's already created. 752 ResultPtr = Resolver.getFunctionStubIfAvailable(F); 753 if (ResultPtr) 754 AddStubToCurrentFunction(ResultPtr); 755 } else { 756 ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F); 757 } 758 if (ResultPtr) return ResultPtr; 759 760 // If this is an external function pointer, we can force the JIT to 761 // 'compile' it, which really just adds it to the map. In dlsym mode, 762 // external functions are forced through a stub, regardless of reloc type. 763 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode() && 764 !MayNeedFarStub && !TheJIT->areDlsymStubsEnabled()) 765 return TheJIT->getPointerToFunction(F); 766 767 // Okay, the function has not been compiled yet, if the target callback 768 // mechanism is capable of rewriting the instruction directly, prefer to do 769 // that instead of emitting a stub. This uses the lazy resolver, so is not 770 // legal if lazy compilation is disabled. 771 if (!MayNeedFarStub && TheJIT->isCompilingLazily()) 772 return Resolver.AddCallbackAtLocation(F, Reference); 773 774 // Otherwise, we have to emit a stub. 775 void *StubAddr = Resolver.getFunctionStub(F); 776 777 // Add the stub to the current function's list of referenced stubs, so we can 778 // deallocate them if the current function is ever freed. It's possible to 779 // return null from getFunctionStub in the case of a weak extern that fails 780 // to resolve. 781 if (StubAddr) 782 AddStubToCurrentFunction(StubAddr); 783 784 return StubAddr; 785} 786 787void *JITEmitter::getPointerToGVIndirectSym(GlobalValue *V, void *Reference) { 788 // Make sure GV is emitted first, and create a stub containing the fully 789 // resolved address. 790 void *GVAddress = getPointerToGlobal(V, Reference, false); 791 void *StubAddr = Resolver.getGlobalValueIndirectSym(V, GVAddress); 792 793 // Add the stub to the current function's list of referenced stubs, so we can 794 // deallocate them if the current function is ever freed. 795 AddStubToCurrentFunction(StubAddr); 796 797 return StubAddr; 798} 799 800void JITEmitter::AddStubToCurrentFunction(void *StubAddr) { 801 assert(CurFn && "Stub added to current function, but current function is 0!"); 802 803 SmallVectorImpl<void*> &StubsUsed = CurFnStubUses[CurFn]; 804 StubsUsed.push_back(StubAddr); 805 806 SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[StubAddr]; 807 FnRefs.insert(CurFn); 808} 809 810void JITEmitter::processDebugLoc(DebugLoc DL, bool BeforePrintingInsn) { 811 if (!DL.isUnknown()) { 812 DebugLocTuple CurDLT = EmissionDetails.MF->getDebugLocTuple(DL); 813 814 if (BeforePrintingInsn) { 815 if (CurDLT.Scope != 0 && PrevDLT != CurDLT) { 816 JITEvent_EmittedFunctionDetails::LineStart NextLine; 817 NextLine.Address = getCurrentPCValue(); 818 NextLine.Loc = DL; 819 EmissionDetails.LineStarts.push_back(NextLine); 820 } 821 822 PrevDLT = CurDLT; 823 } 824 } 825} 826 827static unsigned GetConstantPoolSizeInBytes(MachineConstantPool *MCP, 828 const TargetData *TD) { 829 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants(); 830 if (Constants.empty()) return 0; 831 832 unsigned Size = 0; 833 for (unsigned i = 0, e = Constants.size(); i != e; ++i) { 834 MachineConstantPoolEntry CPE = Constants[i]; 835 unsigned AlignMask = CPE.getAlignment() - 1; 836 Size = (Size + AlignMask) & ~AlignMask; 837 const Type *Ty = CPE.getType(); 838 Size += TD->getTypeAllocSize(Ty); 839 } 840 return Size; 841} 842 843static unsigned GetJumpTableSizeInBytes(MachineJumpTableInfo *MJTI) { 844 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables(); 845 if (JT.empty()) return 0; 846 847 unsigned NumEntries = 0; 848 for (unsigned i = 0, e = JT.size(); i != e; ++i) 849 NumEntries += JT[i].MBBs.size(); 850 851 unsigned EntrySize = MJTI->getEntrySize(); 852 853 return NumEntries * EntrySize; 854} 855 856static uintptr_t RoundUpToAlign(uintptr_t Size, unsigned Alignment) { 857 if (Alignment == 0) Alignment = 1; 858 // Since we do not know where the buffer will be allocated, be pessimistic. 859 return Size + Alignment; 860} 861 862/// addSizeOfGlobal - add the size of the global (plus any alignment padding) 863/// into the running total Size. 864 865unsigned JITEmitter::addSizeOfGlobal(const GlobalVariable *GV, unsigned Size) { 866 const Type *ElTy = GV->getType()->getElementType(); 867 size_t GVSize = (size_t)TheJIT->getTargetData()->getTypeAllocSize(ElTy); 868 size_t GVAlign = 869 (size_t)TheJIT->getTargetData()->getPreferredAlignment(GV); 870 DEBUG(errs() << "JIT: Adding in size " << GVSize << " alignment " << GVAlign); 871 DEBUG(GV->dump()); 872 // Assume code section ends with worst possible alignment, so first 873 // variable needs maximal padding. 874 if (Size==0) 875 Size = 1; 876 Size = ((Size+GVAlign-1)/GVAlign)*GVAlign; 877 Size += GVSize; 878 return Size; 879} 880 881/// addSizeOfGlobalsInConstantVal - find any globals that we haven't seen yet 882/// but are referenced from the constant; put them in GVSet and add their 883/// size into the running total Size. 884 885unsigned JITEmitter::addSizeOfGlobalsInConstantVal(const Constant *C, 886 unsigned Size) { 887 // If its undefined, return the garbage. 888 if (isa<UndefValue>(C)) 889 return Size; 890 891 // If the value is a ConstantExpr 892 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) { 893 Constant *Op0 = CE->getOperand(0); 894 switch (CE->getOpcode()) { 895 case Instruction::GetElementPtr: 896 case Instruction::Trunc: 897 case Instruction::ZExt: 898 case Instruction::SExt: 899 case Instruction::FPTrunc: 900 case Instruction::FPExt: 901 case Instruction::UIToFP: 902 case Instruction::SIToFP: 903 case Instruction::FPToUI: 904 case Instruction::FPToSI: 905 case Instruction::PtrToInt: 906 case Instruction::IntToPtr: 907 case Instruction::BitCast: { 908 Size = addSizeOfGlobalsInConstantVal(Op0, Size); 909 break; 910 } 911 case Instruction::Add: 912 case Instruction::FAdd: 913 case Instruction::Sub: 914 case Instruction::FSub: 915 case Instruction::Mul: 916 case Instruction::FMul: 917 case Instruction::UDiv: 918 case Instruction::SDiv: 919 case Instruction::URem: 920 case Instruction::SRem: 921 case Instruction::And: 922 case Instruction::Or: 923 case Instruction::Xor: { 924 Size = addSizeOfGlobalsInConstantVal(Op0, Size); 925 Size = addSizeOfGlobalsInConstantVal(CE->getOperand(1), Size); 926 break; 927 } 928 default: { 929 std::string msg; 930 raw_string_ostream Msg(msg); 931 Msg << "ConstantExpr not handled: " << *CE; 932 llvm_report_error(Msg.str()); 933 } 934 } 935 } 936 937 if (C->getType()->getTypeID() == Type::PointerTyID) 938 if (const GlobalVariable* GV = dyn_cast<GlobalVariable>(C)) 939 if (GVSet.insert(GV)) 940 Size = addSizeOfGlobal(GV, Size); 941 942 return Size; 943} 944 945/// addSizeOfGLobalsInInitializer - handle any globals that we haven't seen yet 946/// but are referenced from the given initializer. 947 948unsigned JITEmitter::addSizeOfGlobalsInInitializer(const Constant *Init, 949 unsigned Size) { 950 if (!isa<UndefValue>(Init) && 951 !isa<ConstantVector>(Init) && 952 !isa<ConstantAggregateZero>(Init) && 953 !isa<ConstantArray>(Init) && 954 !isa<ConstantStruct>(Init) && 955 Init->getType()->isFirstClassType()) 956 Size = addSizeOfGlobalsInConstantVal(Init, Size); 957 return Size; 958} 959 960/// GetSizeOfGlobalsInBytes - walk the code for the function, looking for 961/// globals; then walk the initializers of those globals looking for more. 962/// If their size has not been considered yet, add it into the running total 963/// Size. 964 965unsigned JITEmitter::GetSizeOfGlobalsInBytes(MachineFunction &MF) { 966 unsigned Size = 0; 967 GVSet.clear(); 968 969 for (MachineFunction::iterator MBB = MF.begin(), E = MF.end(); 970 MBB != E; ++MBB) { 971 for (MachineBasicBlock::const_iterator I = MBB->begin(), E = MBB->end(); 972 I != E; ++I) { 973 const TargetInstrDesc &Desc = I->getDesc(); 974 const MachineInstr &MI = *I; 975 unsigned NumOps = Desc.getNumOperands(); 976 for (unsigned CurOp = 0; CurOp < NumOps; CurOp++) { 977 const MachineOperand &MO = MI.getOperand(CurOp); 978 if (MO.isGlobal()) { 979 GlobalValue* V = MO.getGlobal(); 980 const GlobalVariable *GV = dyn_cast<const GlobalVariable>(V); 981 if (!GV) 982 continue; 983 // If seen in previous function, it will have an entry here. 984 if (TheJIT->getPointerToGlobalIfAvailable(GV)) 985 continue; 986 // If seen earlier in this function, it will have an entry here. 987 // FIXME: it should be possible to combine these tables, by 988 // assuming the addresses of the new globals in this module 989 // start at 0 (or something) and adjusting them after codegen 990 // complete. Another possibility is to grab a marker bit in GV. 991 if (GVSet.insert(GV)) 992 // A variable as yet unseen. Add in its size. 993 Size = addSizeOfGlobal(GV, Size); 994 } 995 } 996 } 997 } 998 DEBUG(errs() << "JIT: About to look through initializers\n"); 999 // Look for more globals that are referenced only from initializers. 1000 // GVSet.end is computed each time because the set can grow as we go. 1001 for (SmallPtrSet<const GlobalVariable *, 8>::iterator I = GVSet.begin(); 1002 I != GVSet.end(); I++) { 1003 const GlobalVariable* GV = *I; 1004 if (GV->hasInitializer()) 1005 Size = addSizeOfGlobalsInInitializer(GV->getInitializer(), Size); 1006 } 1007 1008 return Size; 1009} 1010 1011void JITEmitter::startFunction(MachineFunction &F) { 1012 DEBUG(errs() << "JIT: Starting CodeGen of Function " 1013 << F.getFunction()->getName() << "\n"); 1014 1015 uintptr_t ActualSize = 0; 1016 // Set the memory writable, if it's not already 1017 MemMgr->setMemoryWritable(); 1018 if (MemMgr->NeedsExactSize()) { 1019 DEBUG(errs() << "JIT: ExactSize\n"); 1020 const TargetInstrInfo* TII = F.getTarget().getInstrInfo(); 1021 MachineJumpTableInfo *MJTI = F.getJumpTableInfo(); 1022 MachineConstantPool *MCP = F.getConstantPool(); 1023 1024 // Ensure the constant pool/jump table info is at least 4-byte aligned. 1025 ActualSize = RoundUpToAlign(ActualSize, 16); 1026 1027 // Add the alignment of the constant pool 1028 ActualSize = RoundUpToAlign(ActualSize, MCP->getConstantPoolAlignment()); 1029 1030 // Add the constant pool size 1031 ActualSize += GetConstantPoolSizeInBytes(MCP, TheJIT->getTargetData()); 1032 1033 // Add the aligment of the jump table info 1034 ActualSize = RoundUpToAlign(ActualSize, MJTI->getAlignment()); 1035 1036 // Add the jump table size 1037 ActualSize += GetJumpTableSizeInBytes(MJTI); 1038 1039 // Add the alignment for the function 1040 ActualSize = RoundUpToAlign(ActualSize, 1041 std::max(F.getFunction()->getAlignment(), 8U)); 1042 1043 // Add the function size 1044 ActualSize += TII->GetFunctionSizeInBytes(F); 1045 1046 DEBUG(errs() << "JIT: ActualSize before globals " << ActualSize << "\n"); 1047 // Add the size of the globals that will be allocated after this function. 1048 // These are all the ones referenced from this function that were not 1049 // previously allocated. 1050 ActualSize += GetSizeOfGlobalsInBytes(F); 1051 DEBUG(errs() << "JIT: ActualSize after globals " << ActualSize << "\n"); 1052 } else if (SizeEstimate > 0) { 1053 // SizeEstimate will be non-zero on reallocation attempts. 1054 ActualSize = SizeEstimate; 1055 } 1056 1057 BufferBegin = CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(), 1058 ActualSize); 1059 BufferEnd = BufferBegin+ActualSize; 1060 EmittedFunctions[F.getFunction()].FunctionBody = BufferBegin; 1061 1062 // Ensure the constant pool/jump table info is at least 4-byte aligned. 1063 emitAlignment(16); 1064 1065 emitConstantPool(F.getConstantPool()); 1066 initJumpTableInfo(F.getJumpTableInfo()); 1067 1068 // About to start emitting the machine code for the function. 1069 emitAlignment(std::max(F.getFunction()->getAlignment(), 8U)); 1070 TheJIT->updateGlobalMapping(F.getFunction(), CurBufferPtr); 1071 EmittedFunctions[F.getFunction()].Code = CurBufferPtr; 1072 1073 MBBLocations.clear(); 1074 1075 EmissionDetails.MF = &F; 1076 EmissionDetails.LineStarts.clear(); 1077} 1078 1079bool JITEmitter::finishFunction(MachineFunction &F) { 1080 if (CurBufferPtr == BufferEnd) { 1081 // We must call endFunctionBody before retrying, because 1082 // deallocateMemForFunction requires it. 1083 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, CurBufferPtr); 1084 retryWithMoreMemory(F); 1085 return true; 1086 } 1087 1088 emitJumpTableInfo(F.getJumpTableInfo()); 1089 1090 // FnStart is the start of the text, not the start of the constant pool and 1091 // other per-function data. 1092 uint8_t *FnStart = 1093 (uint8_t *)TheJIT->getPointerToGlobalIfAvailable(F.getFunction()); 1094 1095 // FnEnd is the end of the function's machine code. 1096 uint8_t *FnEnd = CurBufferPtr; 1097 1098 if (!Relocations.empty()) { 1099 CurFn = F.getFunction(); 1100 NumRelos += Relocations.size(); 1101 1102 // Resolve the relocations to concrete pointers. 1103 for (unsigned i = 0, e = Relocations.size(); i != e; ++i) { 1104 MachineRelocation &MR = Relocations[i]; 1105 void *ResultPtr = 0; 1106 if (!MR.letTargetResolve()) { 1107 if (MR.isExternalSymbol()) { 1108 ResultPtr = TheJIT->getPointerToNamedFunction(MR.getExternalSymbol(), 1109 false); 1110 DEBUG(errs() << "JIT: Map \'" << MR.getExternalSymbol() << "\' to [" 1111 << ResultPtr << "]\n"); 1112 1113 // If the target REALLY wants a stub for this function, emit it now. 1114 if (MR.mayNeedFarStub()) { 1115 if (!TheJIT->areDlsymStubsEnabled()) { 1116 ResultPtr = Resolver.getExternalFunctionStub(ResultPtr); 1117 } else { 1118 void *&Stub = ExtFnStubs[MR.getExternalSymbol()]; 1119 if (!Stub) { 1120 Stub = Resolver.getExternalFunctionStub((void *)&Stub); 1121 AddStubToCurrentFunction(Stub); 1122 } 1123 ResultPtr = Stub; 1124 } 1125 } 1126 } else if (MR.isGlobalValue()) { 1127 ResultPtr = getPointerToGlobal(MR.getGlobalValue(), 1128 BufferBegin+MR.getMachineCodeOffset(), 1129 MR.mayNeedFarStub()); 1130 } else if (MR.isIndirectSymbol()) { 1131 ResultPtr = getPointerToGVIndirectSym( 1132 MR.getGlobalValue(), BufferBegin+MR.getMachineCodeOffset()); 1133 } else if (MR.isBasicBlock()) { 1134 ResultPtr = (void*)getMachineBasicBlockAddress(MR.getBasicBlock()); 1135 } else if (MR.isConstantPoolIndex()) { 1136 ResultPtr = (void*)getConstantPoolEntryAddress(MR.getConstantPoolIndex()); 1137 } else { 1138 assert(MR.isJumpTableIndex()); 1139 ResultPtr=(void*)getJumpTableEntryAddress(MR.getJumpTableIndex()); 1140 } 1141 1142 MR.setResultPointer(ResultPtr); 1143 } 1144 1145 // if we are managing the GOT and the relocation wants an index, 1146 // give it one 1147 if (MR.isGOTRelative() && MemMgr->isManagingGOT()) { 1148 unsigned idx = Resolver.getGOTIndexForAddr(ResultPtr); 1149 MR.setGOTIndex(idx); 1150 if (((void**)MemMgr->getGOTBase())[idx] != ResultPtr) { 1151 DEBUG(errs() << "JIT: GOT was out of date for " << ResultPtr 1152 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx] 1153 << "\n"); 1154 ((void**)MemMgr->getGOTBase())[idx] = ResultPtr; 1155 } 1156 } 1157 } 1158 1159 CurFn = 0; 1160 TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0], 1161 Relocations.size(), MemMgr->getGOTBase()); 1162 } 1163 1164 // Update the GOT entry for F to point to the new code. 1165 if (MemMgr->isManagingGOT()) { 1166 unsigned idx = Resolver.getGOTIndexForAddr((void*)BufferBegin); 1167 if (((void**)MemMgr->getGOTBase())[idx] != (void*)BufferBegin) { 1168 DEBUG(errs() << "JIT: GOT was out of date for " << (void*)BufferBegin 1169 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx] 1170 << "\n"); 1171 ((void**)MemMgr->getGOTBase())[idx] = (void*)BufferBegin; 1172 } 1173 } 1174 1175 // CurBufferPtr may have moved beyond FnEnd, due to memory allocation for 1176 // global variables that were referenced in the relocations. 1177 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, CurBufferPtr); 1178 1179 if (CurBufferPtr == BufferEnd) { 1180 retryWithMoreMemory(F); 1181 return true; 1182 } else { 1183 // Now that we've succeeded in emitting the function, reset the 1184 // SizeEstimate back down to zero. 1185 SizeEstimate = 0; 1186 } 1187 1188 BufferBegin = CurBufferPtr = 0; 1189 NumBytes += FnEnd-FnStart; 1190 1191 // Invalidate the icache if necessary. 1192 sys::Memory::InvalidateInstructionCache(FnStart, FnEnd-FnStart); 1193 1194 TheJIT->NotifyFunctionEmitted(*F.getFunction(), FnStart, FnEnd-FnStart, 1195 EmissionDetails); 1196 1197 DEBUG(errs() << "JIT: Finished CodeGen of [" << (void*)FnStart 1198 << "] Function: " << F.getFunction()->getName() 1199 << ": " << (FnEnd-FnStart) << " bytes of text, " 1200 << Relocations.size() << " relocations\n"); 1201 1202 Relocations.clear(); 1203 ConstPoolAddresses.clear(); 1204 1205 // Mark code region readable and executable if it's not so already. 1206 MemMgr->setMemoryExecutable(); 1207 1208 DEBUG( 1209 if (sys::hasDisassembler()) { 1210 errs() << "JIT: Disassembled code:\n"; 1211 errs() << sys::disassembleBuffer(FnStart, FnEnd-FnStart, 1212 (uintptr_t)FnStart); 1213 } else { 1214 errs() << "JIT: Binary code:\n"; 1215 uint8_t* q = FnStart; 1216 for (int i = 0; q < FnEnd; q += 4, ++i) { 1217 if (i == 4) 1218 i = 0; 1219 if (i == 0) 1220 errs() << "JIT: " << (long)(q - FnStart) << ": "; 1221 bool Done = false; 1222 for (int j = 3; j >= 0; --j) { 1223 if (q + j >= FnEnd) 1224 Done = true; 1225 else 1226 errs() << (unsigned short)q[j]; 1227 } 1228 if (Done) 1229 break; 1230 errs() << ' '; 1231 if (i == 3) 1232 errs() << '\n'; 1233 } 1234 errs()<< '\n'; 1235 } 1236 ); 1237 1238 if (DwarfExceptionHandling || JITEmitDebugInfo) { 1239 uintptr_t ActualSize = 0; 1240 SavedBufferBegin = BufferBegin; 1241 SavedBufferEnd = BufferEnd; 1242 SavedCurBufferPtr = CurBufferPtr; 1243 1244 if (MemMgr->NeedsExactSize()) { 1245 ActualSize = DE->GetDwarfTableSizeInBytes(F, *this, FnStart, FnEnd); 1246 } 1247 1248 BufferBegin = CurBufferPtr = MemMgr->startExceptionTable(F.getFunction(), 1249 ActualSize); 1250 BufferEnd = BufferBegin+ActualSize; 1251 EmittedFunctions[F.getFunction()].ExceptionTable = BufferBegin; 1252 uint8_t *EhStart; 1253 uint8_t *FrameRegister = DE->EmitDwarfTable(F, *this, FnStart, FnEnd, 1254 EhStart); 1255 MemMgr->endExceptionTable(F.getFunction(), BufferBegin, CurBufferPtr, 1256 FrameRegister); 1257 uint8_t *EhEnd = CurBufferPtr; 1258 BufferBegin = SavedBufferBegin; 1259 BufferEnd = SavedBufferEnd; 1260 CurBufferPtr = SavedCurBufferPtr; 1261 1262 if (DwarfExceptionHandling) { 1263 TheJIT->RegisterTable(FrameRegister); 1264 } 1265 1266 if (JITEmitDebugInfo) { 1267 DebugInfo I; 1268 I.FnStart = FnStart; 1269 I.FnEnd = FnEnd; 1270 I.EhStart = EhStart; 1271 I.EhEnd = EhEnd; 1272 DR->RegisterFunction(F.getFunction(), I); 1273 } 1274 } 1275 1276 if (MMI) 1277 MMI->EndFunction(); 1278 1279 return false; 1280} 1281 1282void JITEmitter::retryWithMoreMemory(MachineFunction &F) { 1283 DEBUG(errs() << "JIT: Ran out of space for native code. Reattempting.\n"); 1284 Relocations.clear(); // Clear the old relocations or we'll reapply them. 1285 ConstPoolAddresses.clear(); 1286 ++NumRetries; 1287 deallocateMemForFunction(F.getFunction()); 1288 // Try again with at least twice as much free space. 1289 SizeEstimate = (uintptr_t)(2 * (BufferEnd - BufferBegin)); 1290} 1291 1292/// deallocateMemForFunction - Deallocate all memory for the specified 1293/// function body. Also drop any references the function has to stubs. 1294/// May be called while the Function is being destroyed inside ~Value(). 1295void JITEmitter::deallocateMemForFunction(const Function *F) { 1296 ValueMap<const Function *, EmittedCode, EmittedFunctionConfig>::iterator 1297 Emitted = EmittedFunctions.find(F); 1298 if (Emitted != EmittedFunctions.end()) { 1299 MemMgr->deallocateFunctionBody(Emitted->second.FunctionBody); 1300 MemMgr->deallocateExceptionTable(Emitted->second.ExceptionTable); 1301 TheJIT->NotifyFreeingMachineCode(Emitted->second.Code); 1302 1303 EmittedFunctions.erase(Emitted); 1304 } 1305 1306 // TODO: Do we need to unregister exception handling information from libgcc 1307 // here? 1308 1309 if (JITEmitDebugInfo) { 1310 DR->UnregisterFunction(F); 1311 } 1312 1313 // If the function did not reference any stubs, return. 1314 if (CurFnStubUses.find(F) == CurFnStubUses.end()) 1315 return; 1316 1317 // For each referenced stub, erase the reference to this function, and then 1318 // erase the list of referenced stubs. 1319 SmallVectorImpl<void *> &StubList = CurFnStubUses[F]; 1320 for (unsigned i = 0, e = StubList.size(); i != e; ++i) { 1321 void *Stub = StubList[i]; 1322 1323 // If we already invalidated this stub for this function, continue. 1324 if (StubFnRefs.count(Stub) == 0) 1325 continue; 1326 1327 SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[Stub]; 1328 FnRefs.erase(F); 1329 1330 // If this function was the last reference to the stub, invalidate the stub 1331 // in the JITResolver. Were there a memory manager deallocateStub routine, 1332 // we could call that at this point too. 1333 if (FnRefs.empty()) { 1334 DEBUG(errs() << "\nJIT: Invalidated Stub at [" << Stub << "]\n"); 1335 StubFnRefs.erase(Stub); 1336 1337 // Invalidate the stub. If it is a GV stub, update the JIT's global 1338 // mapping for that GV to zero, otherwise, search the string map of 1339 // external function names to stubs and remove the entry for this stub. 1340 GlobalValue *GV = Resolver.invalidateStub(Stub); 1341 if (GV) { 1342 TheJIT->updateGlobalMapping(GV, 0); 1343 } else { 1344 for (StringMapIterator<void*> i = ExtFnStubs.begin(), 1345 e = ExtFnStubs.end(); i != e; ++i) { 1346 if (i->second == Stub) { 1347 ExtFnStubs.erase(i); 1348 break; 1349 } 1350 } 1351 } 1352 } 1353 } 1354 CurFnStubUses.erase(F); 1355} 1356 1357 1358void* JITEmitter::allocateSpace(uintptr_t Size, unsigned Alignment) { 1359 if (BufferBegin) 1360 return JITCodeEmitter::allocateSpace(Size, Alignment); 1361 1362 // create a new memory block if there is no active one. 1363 // care must be taken so that BufferBegin is invalidated when a 1364 // block is trimmed 1365 BufferBegin = CurBufferPtr = MemMgr->allocateSpace(Size, Alignment); 1366 BufferEnd = BufferBegin+Size; 1367 return CurBufferPtr; 1368} 1369 1370void* JITEmitter::allocateGlobal(uintptr_t Size, unsigned Alignment) { 1371 // Delegate this call through the memory manager. 1372 return MemMgr->allocateGlobal(Size, Alignment); 1373} 1374 1375void JITEmitter::emitConstantPool(MachineConstantPool *MCP) { 1376 if (TheJIT->getJITInfo().hasCustomConstantPool()) 1377 return; 1378 1379 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants(); 1380 if (Constants.empty()) return; 1381 1382 unsigned Size = GetConstantPoolSizeInBytes(MCP, TheJIT->getTargetData()); 1383 unsigned Align = MCP->getConstantPoolAlignment(); 1384 ConstantPoolBase = allocateSpace(Size, Align); 1385 ConstantPool = MCP; 1386 1387 if (ConstantPoolBase == 0) return; // Buffer overflow. 1388 1389 DEBUG(errs() << "JIT: Emitted constant pool at [" << ConstantPoolBase 1390 << "] (size: " << Size << ", alignment: " << Align << ")\n"); 1391 1392 // Initialize the memory for all of the constant pool entries. 1393 unsigned Offset = 0; 1394 for (unsigned i = 0, e = Constants.size(); i != e; ++i) { 1395 MachineConstantPoolEntry CPE = Constants[i]; 1396 unsigned AlignMask = CPE.getAlignment() - 1; 1397 Offset = (Offset + AlignMask) & ~AlignMask; 1398 1399 uintptr_t CAddr = (uintptr_t)ConstantPoolBase + Offset; 1400 ConstPoolAddresses.push_back(CAddr); 1401 if (CPE.isMachineConstantPoolEntry()) { 1402 // FIXME: add support to lower machine constant pool values into bytes! 1403 llvm_report_error("Initialize memory with machine specific constant pool" 1404 "entry has not been implemented!"); 1405 } 1406 TheJIT->InitializeMemory(CPE.Val.ConstVal, (void*)CAddr); 1407 DEBUG(errs() << "JIT: CP" << i << " at [0x"; 1408 errs().write_hex(CAddr) << "]\n"); 1409 1410 const Type *Ty = CPE.Val.ConstVal->getType(); 1411 Offset += TheJIT->getTargetData()->getTypeAllocSize(Ty); 1412 } 1413} 1414 1415void JITEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) { 1416 if (TheJIT->getJITInfo().hasCustomJumpTables()) 1417 return; 1418 1419 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables(); 1420 if (JT.empty()) return; 1421 1422 unsigned NumEntries = 0; 1423 for (unsigned i = 0, e = JT.size(); i != e; ++i) 1424 NumEntries += JT[i].MBBs.size(); 1425 1426 unsigned EntrySize = MJTI->getEntrySize(); 1427 1428 // Just allocate space for all the jump tables now. We will fix up the actual 1429 // MBB entries in the tables after we emit the code for each block, since then 1430 // we will know the final locations of the MBBs in memory. 1431 JumpTable = MJTI; 1432 JumpTableBase = allocateSpace(NumEntries * EntrySize, MJTI->getAlignment()); 1433} 1434 1435void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) { 1436 if (TheJIT->getJITInfo().hasCustomJumpTables()) 1437 return; 1438 1439 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables(); 1440 if (JT.empty() || JumpTableBase == 0) return; 1441 1442 if (TargetMachine::getRelocationModel() == Reloc::PIC_) { 1443 assert(MJTI->getEntrySize() == 4 && "Cross JIT'ing?"); 1444 // For each jump table, place the offset from the beginning of the table 1445 // to the target address. 1446 int *SlotPtr = (int*)JumpTableBase; 1447 1448 for (unsigned i = 0, e = JT.size(); i != e; ++i) { 1449 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs; 1450 // Store the offset of the basic block for this jump table slot in the 1451 // memory we allocated for the jump table in 'initJumpTableInfo' 1452 uintptr_t Base = (uintptr_t)SlotPtr; 1453 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) { 1454 uintptr_t MBBAddr = getMachineBasicBlockAddress(MBBs[mi]); 1455 *SlotPtr++ = TheJIT->getJITInfo().getPICJumpTableEntry(MBBAddr, Base); 1456 } 1457 } 1458 } else { 1459 assert(MJTI->getEntrySize() == sizeof(void*) && "Cross JIT'ing?"); 1460 1461 // For each jump table, map each target in the jump table to the address of 1462 // an emitted MachineBasicBlock. 1463 intptr_t *SlotPtr = (intptr_t*)JumpTableBase; 1464 1465 for (unsigned i = 0, e = JT.size(); i != e; ++i) { 1466 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs; 1467 // Store the address of the basic block for this jump table slot in the 1468 // memory we allocated for the jump table in 'initJumpTableInfo' 1469 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) 1470 *SlotPtr++ = getMachineBasicBlockAddress(MBBs[mi]); 1471 } 1472 } 1473} 1474 1475void JITEmitter::startGVStub(const GlobalValue* GV, unsigned StubSize, 1476 unsigned Alignment) { 1477 SavedBufferBegin = BufferBegin; 1478 SavedBufferEnd = BufferEnd; 1479 SavedCurBufferPtr = CurBufferPtr; 1480 1481 BufferBegin = CurBufferPtr = MemMgr->allocateStub(GV, StubSize, Alignment); 1482 BufferEnd = BufferBegin+StubSize+1; 1483} 1484 1485void JITEmitter::startGVStub(const GlobalValue* GV, void *Buffer, 1486 unsigned StubSize) { 1487 SavedBufferBegin = BufferBegin; 1488 SavedBufferEnd = BufferEnd; 1489 SavedCurBufferPtr = CurBufferPtr; 1490 1491 BufferBegin = CurBufferPtr = (uint8_t *)Buffer; 1492 BufferEnd = BufferBegin+StubSize+1; 1493} 1494 1495void *JITEmitter::finishGVStub(const GlobalValue* GV) { 1496 NumBytes += getCurrentPCOffset(); 1497 std::swap(SavedBufferBegin, BufferBegin); 1498 BufferEnd = SavedBufferEnd; 1499 CurBufferPtr = SavedCurBufferPtr; 1500 return SavedBufferBegin; 1501} 1502 1503// getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry 1504// in the constant pool that was last emitted with the 'emitConstantPool' 1505// method. 1506// 1507uintptr_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) const { 1508 assert(ConstantNum < ConstantPool->getConstants().size() && 1509 "Invalid ConstantPoolIndex!"); 1510 return ConstPoolAddresses[ConstantNum]; 1511} 1512 1513// getJumpTableEntryAddress - Return the address of the JumpTable with index 1514// 'Index' in the jumpp table that was last initialized with 'initJumpTableInfo' 1515// 1516uintptr_t JITEmitter::getJumpTableEntryAddress(unsigned Index) const { 1517 const std::vector<MachineJumpTableEntry> &JT = JumpTable->getJumpTables(); 1518 assert(Index < JT.size() && "Invalid jump table index!"); 1519 1520 unsigned Offset = 0; 1521 unsigned EntrySize = JumpTable->getEntrySize(); 1522 1523 for (unsigned i = 0; i < Index; ++i) 1524 Offset += JT[i].MBBs.size(); 1525 1526 Offset *= EntrySize; 1527 1528 return (uintptr_t)((char *)JumpTableBase + Offset); 1529} 1530 1531void JITEmitter::EmittedFunctionConfig::onDelete( 1532 JITEmitter *Emitter, const Function *F) { 1533 Emitter->deallocateMemForFunction(F); 1534} 1535void JITEmitter::EmittedFunctionConfig::onRAUW( 1536 JITEmitter *, const Function*, const Function*) { 1537 llvm_unreachable("The JIT doesn't know how to handle a" 1538 " RAUW on a value it has emitted."); 1539} 1540 1541 1542//===----------------------------------------------------------------------===// 1543// Public interface to this file 1544//===----------------------------------------------------------------------===// 1545 1546JITCodeEmitter *JIT::createEmitter(JIT &jit, JITMemoryManager *JMM, 1547 TargetMachine &tm) { 1548 return new JITEmitter(jit, JMM, tm); 1549} 1550 1551// getPointerToNamedFunction - This function is used as a global wrapper to 1552// JIT::getPointerToNamedFunction for the purpose of resolving symbols when 1553// bugpoint is debugging the JIT. In that scenario, we are loading an .so and 1554// need to resolve function(s) that are being mis-codegenerated, so we need to 1555// resolve their addresses at runtime, and this is the way to do it. 1556extern "C" { 1557 void *getPointerToNamedFunction(const char *Name) { 1558 if (Function *F = TheJIT->FindFunctionNamed(Name)) 1559 return TheJIT->getPointerToFunction(F); 1560 return TheJIT->getPointerToNamedFunction(Name); 1561 } 1562} 1563 1564// getPointerToFunctionOrStub - If the specified function has been 1565// code-gen'd, return a pointer to the function. If not, compile it, or use 1566// a stub to implement lazy compilation if available. 1567// 1568void *JIT::getPointerToFunctionOrStub(Function *F) { 1569 // If we have already code generated the function, just return the address. 1570 if (void *Addr = getPointerToGlobalIfAvailable(F)) 1571 return Addr; 1572 1573 // Get a stub if the target supports it. 1574 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?"); 1575 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter()); 1576 return JE->getJITResolver().getFunctionStub(F); 1577} 1578 1579void JIT::updateFunctionStub(Function *F) { 1580 // Get the empty stub we generated earlier. 1581 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?"); 1582 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter()); 1583 void *Stub = JE->getJITResolver().getFunctionStub(F); 1584 1585 // Tell the target jit info to rewrite the stub at the specified address, 1586 // rather than creating a new one. 1587 void *Addr = getPointerToGlobalIfAvailable(F); 1588 getJITInfo().emitFunctionStubAtAddr(F, Addr, Stub, *getCodeEmitter()); 1589} 1590 1591/// updateDlsymStubTable - Emit the data necessary to relocate the stubs 1592/// that were emitted during code generation. 1593/// 1594void JIT::updateDlsymStubTable() { 1595 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?"); 1596 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter()); 1597 1598 SmallVector<GlobalValue*, 8> GVs; 1599 SmallVector<void*, 8> Ptrs; 1600 const StringMap<void *> &ExtFns = JE->getExternalFnStubs(); 1601 1602 JE->getJITResolver().getRelocatableGVs(GVs, Ptrs); 1603 1604 unsigned nStubs = GVs.size() + ExtFns.size(); 1605 1606 // If there are no relocatable stubs, return. 1607 if (nStubs == 0) 1608 return; 1609 1610 // If there are no new relocatable stubs, return. 1611 void *CurTable = JE->getMemMgr()->getDlsymTable(); 1612 if (CurTable && (*(unsigned *)CurTable == nStubs)) 1613 return; 1614 1615 // Calculate the size of the stub info 1616 unsigned offset = 4 + 4 * nStubs + sizeof(intptr_t) * nStubs; 1617 1618 SmallVector<unsigned, 8> Offsets; 1619 for (unsigned i = 0; i != GVs.size(); ++i) { 1620 Offsets.push_back(offset); 1621 offset += GVs[i]->getName().size() + 1; 1622 } 1623 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end(); 1624 i != e; ++i) { 1625 Offsets.push_back(offset); 1626 offset += strlen(i->first()) + 1; 1627 } 1628 1629 // Allocate space for the new "stub", which contains the dlsym table. 1630 JE->startGVStub(0, offset, 4); 1631 1632 // Emit the number of records 1633 JE->emitInt32(nStubs); 1634 1635 // Emit the string offsets 1636 for (unsigned i = 0; i != nStubs; ++i) 1637 JE->emitInt32(Offsets[i]); 1638 1639 // Emit the pointers. Verify that they are at least 2-byte aligned, and set 1640 // the low bit to 0 == GV, 1 == Function, so that the client code doing the 1641 // relocation can write the relocated pointer at the appropriate place in 1642 // the stub. 1643 for (unsigned i = 0; i != GVs.size(); ++i) { 1644 intptr_t Ptr = (intptr_t)Ptrs[i]; 1645 assert((Ptr & 1) == 0 && "Stub pointers must be at least 2-byte aligned!"); 1646 1647 if (isa<Function>(GVs[i])) 1648 Ptr |= (intptr_t)1; 1649 1650 if (sizeof(Ptr) == 8) 1651 JE->emitInt64(Ptr); 1652 else 1653 JE->emitInt32(Ptr); 1654 } 1655 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end(); 1656 i != e; ++i) { 1657 intptr_t Ptr = (intptr_t)i->second | 1; 1658 1659 if (sizeof(Ptr) == 8) 1660 JE->emitInt64(Ptr); 1661 else 1662 JE->emitInt32(Ptr); 1663 } 1664 1665 // Emit the strings. 1666 for (unsigned i = 0; i != GVs.size(); ++i) 1667 JE->emitString(GVs[i]->getName()); 1668 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end(); 1669 i != e; ++i) 1670 JE->emitString(i->first()); 1671 1672 // Tell the JIT memory manager where it is. The JIT Memory Manager will 1673 // deallocate space for the old one, if one existed. 1674 JE->getMemMgr()->SetDlsymTable(JE->finishGVStub(0)); 1675} 1676 1677/// freeMachineCodeForFunction - release machine code memory for given Function. 1678/// 1679void JIT::freeMachineCodeForFunction(Function *F) { 1680 // Delete translation for this from the ExecutionEngine, so it will get 1681 // retranslated next time it is used. 1682 updateGlobalMapping(F, 0); 1683 1684 // Free the actual memory for the function body and related stuff. 1685 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?"); 1686 cast<JITEmitter>(JCE)->deallocateMemForFunction(F); 1687} 1688