JITEmitter.cpp revision 1b747ad8a0694b86e8d98a8b9a05ddfe74ec0cd3
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 "JITDwarfEmitter.h" 18#include "llvm/Constants.h" 19#include "llvm/Module.h" 20#include "llvm/DerivedTypes.h" 21#include "llvm/CodeGen/JITCodeEmitter.h" 22#include "llvm/CodeGen/MachineFunction.h" 23#include "llvm/CodeGen/MachineConstantPool.h" 24#include "llvm/CodeGen/MachineJumpTableInfo.h" 25#include "llvm/CodeGen/MachineModuleInfo.h" 26#include "llvm/CodeGen/MachineRelocation.h" 27#include "llvm/ExecutionEngine/GenericValue.h" 28#include "llvm/ExecutionEngine/JITEventListener.h" 29#include "llvm/ExecutionEngine/JITMemoryManager.h" 30#include "llvm/CodeGen/MachineCodeInfo.h" 31#include "llvm/Target/TargetData.h" 32#include "llvm/Target/TargetJITInfo.h" 33#include "llvm/Target/TargetMachine.h" 34#include "llvm/Target/TargetOptions.h" 35#include "llvm/Support/Debug.h" 36#include "llvm/Support/ErrorHandling.h" 37#include "llvm/Support/MutexGuard.h" 38#include "llvm/Support/ValueHandle.h" 39#include "llvm/Support/raw_ostream.h" 40#include "llvm/System/Disassembler.h" 41#include "llvm/System/Memory.h" 42#include "llvm/Target/TargetInstrInfo.h" 43#include "llvm/ADT/SmallPtrSet.h" 44#include "llvm/ADT/SmallVector.h" 45#include "llvm/ADT/Statistic.h" 46#include <algorithm> 47#ifndef NDEBUG 48#include <iomanip> 49#endif 50using namespace llvm; 51 52STATISTIC(NumBytes, "Number of bytes of machine code compiled"); 53STATISTIC(NumRelos, "Number of relocations applied"); 54STATISTIC(NumRetries, "Number of retries with more memory"); 55static JIT *TheJIT = 0; 56 57 58//===----------------------------------------------------------------------===// 59// JIT lazy compilation code. 60// 61namespace { 62 class JITResolverState { 63 public: 64 typedef std::map<AssertingVH<Function>, void*> FunctionToStubMapTy; 65 typedef std::map<void*, Function*> StubToFunctionMapTy; 66 typedef std::map<AssertingVH<GlobalValue>, void*> GlobalToIndirectSymMapTy; 67 private: 68 /// FunctionToStubMap - Keep track of the stub created for a particular 69 /// function so that we can reuse them if necessary. 70 FunctionToStubMapTy FunctionToStubMap; 71 72 /// StubToFunctionMap - Keep track of the function that each stub 73 /// corresponds to. 74 StubToFunctionMapTy StubToFunctionMap; 75 76 /// GlobalToIndirectSymMap - Keep track of the indirect symbol created for a 77 /// particular GlobalVariable so that we can reuse them if necessary. 78 GlobalToIndirectSymMapTy GlobalToIndirectSymMap; 79 80 public: 81 FunctionToStubMapTy& getFunctionToStubMap(const MutexGuard& locked) { 82 assert(locked.holds(TheJIT->lock)); 83 return FunctionToStubMap; 84 } 85 86 StubToFunctionMapTy& getStubToFunctionMap(const MutexGuard& locked) { 87 assert(locked.holds(TheJIT->lock)); 88 return StubToFunctionMap; 89 } 90 91 GlobalToIndirectSymMapTy& getGlobalToIndirectSymMap(const MutexGuard& locked) { 92 assert(locked.holds(TheJIT->lock)); 93 return GlobalToIndirectSymMap; 94 } 95 }; 96 97 /// JITResolver - Keep track of, and resolve, call sites for functions that 98 /// have not yet been compiled. 99 class JITResolver { 100 typedef JITResolverState::FunctionToStubMapTy FunctionToStubMapTy; 101 typedef JITResolverState::StubToFunctionMapTy StubToFunctionMapTy; 102 typedef JITResolverState::GlobalToIndirectSymMapTy GlobalToIndirectSymMapTy; 103 104 /// LazyResolverFn - The target lazy resolver function that we actually 105 /// rewrite instructions to use. 106 TargetJITInfo::LazyResolverFn LazyResolverFn; 107 108 JITResolverState state; 109 110 /// ExternalFnToStubMap - This is the equivalent of FunctionToStubMap for 111 /// external functions. 112 std::map<void*, void*> ExternalFnToStubMap; 113 114 /// revGOTMap - map addresses to indexes in the GOT 115 std::map<void*, unsigned> revGOTMap; 116 unsigned nextGOTIndex; 117 118 static JITResolver *TheJITResolver; 119 public: 120 explicit JITResolver(JIT &jit) : nextGOTIndex(0) { 121 TheJIT = &jit; 122 123 LazyResolverFn = jit.getJITInfo().getLazyResolverFunction(JITCompilerFn); 124 assert(TheJITResolver == 0 && "Multiple JIT resolvers?"); 125 TheJITResolver = this; 126 } 127 128 ~JITResolver() { 129 TheJITResolver = 0; 130 } 131 132 /// getFunctionStubIfAvailable - This returns a pointer to a function stub 133 /// if it has already been created. 134 void *getFunctionStubIfAvailable(Function *F); 135 136 /// getFunctionStub - This returns a pointer to a function stub, creating 137 /// one on demand as needed. If empty is true, create a function stub 138 /// pointing at address 0, to be filled in later. 139 void *getFunctionStub(Function *F); 140 141 /// getExternalFunctionStub - Return a stub for the function at the 142 /// specified address, created lazily on demand. 143 void *getExternalFunctionStub(void *FnAddr); 144 145 /// getGlobalValueIndirectSym - Return an indirect symbol containing the 146 /// specified GV address. 147 void *getGlobalValueIndirectSym(GlobalValue *V, void *GVAddress); 148 149 /// AddCallbackAtLocation - If the target is capable of rewriting an 150 /// instruction without the use of a stub, record the location of the use so 151 /// we know which function is being used at the location. 152 void *AddCallbackAtLocation(Function *F, void *Location) { 153 MutexGuard locked(TheJIT->lock); 154 /// Get the target-specific JIT resolver function. 155 state.getStubToFunctionMap(locked)[Location] = F; 156 return (void*)(intptr_t)LazyResolverFn; 157 } 158 159 void getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs, 160 SmallVectorImpl<void*> &Ptrs); 161 162 GlobalValue *invalidateStub(void *Stub); 163 164 /// getGOTIndexForAddress - Return a new or existing index in the GOT for 165 /// an address. This function only manages slots, it does not manage the 166 /// contents of the slots or the memory associated with the GOT. 167 unsigned getGOTIndexForAddr(void *addr); 168 169 /// JITCompilerFn - This function is called to resolve a stub to a compiled 170 /// address. If the LLVM Function corresponding to the stub has not yet 171 /// been compiled, this function compiles it first. 172 static void *JITCompilerFn(void *Stub); 173 }; 174} 175 176JITResolver *JITResolver::TheJITResolver = 0; 177 178/// getFunctionStubIfAvailable - This returns a pointer to a function stub 179/// if it has already been created. 180void *JITResolver::getFunctionStubIfAvailable(Function *F) { 181 MutexGuard locked(TheJIT->lock); 182 183 // If we already have a stub for this function, recycle it. 184 void *&Stub = state.getFunctionToStubMap(locked)[F]; 185 return Stub; 186} 187 188/// getFunctionStub - This returns a pointer to a function stub, creating 189/// one on demand as needed. 190void *JITResolver::getFunctionStub(Function *F) { 191 MutexGuard locked(TheJIT->lock); 192 193 // If we already have a stub for this function, recycle it. 194 void *&Stub = state.getFunctionToStubMap(locked)[F]; 195 if (Stub) return Stub; 196 197 // Call the lazy resolver function unless we are JIT'ing non-lazily, in which 198 // case we must resolve the symbol now. 199 void *Actual = TheJIT->isLazyCompilationDisabled() 200 ? (void *)0 : (void *)(intptr_t)LazyResolverFn; 201 202 // If this is an external declaration, attempt to resolve the address now 203 // to place in the stub. 204 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode()) { 205 Actual = TheJIT->getPointerToFunction(F); 206 207 // If we resolved the symbol to a null address (eg. a weak external) 208 // don't emit a stub. Return a null pointer to the application. If dlsym 209 // stubs are enabled, not being able to resolve the address is not 210 // meaningful. 211 if (!Actual && !TheJIT->areDlsymStubsEnabled()) return 0; 212 } 213 214 // Codegen a new stub, calling the lazy resolver or the actual address of the 215 // external function, if it was resolved. 216 Stub = TheJIT->getJITInfo().emitFunctionStub(F, Actual, 217 *TheJIT->getCodeEmitter()); 218 219 if (Actual != (void*)(intptr_t)LazyResolverFn) { 220 // If we are getting the stub for an external function, we really want the 221 // address of the stub in the GlobalAddressMap for the JIT, not the address 222 // of the external function. 223 TheJIT->updateGlobalMapping(F, Stub); 224 } 225 226 DEBUG(errs() << "JIT: Stub emitted at [" << Stub << "] for function '" 227 << F->getName() << "'\n"); 228 229 // Finally, keep track of the stub-to-Function mapping so that the 230 // JITCompilerFn knows which function to compile! 231 state.getStubToFunctionMap(locked)[Stub] = F; 232 233 // If we are JIT'ing non-lazily but need to call a function that does not 234 // exist yet, add it to the JIT's work list so that we can fill in the stub 235 // address later. 236 if (!Actual && TheJIT->isLazyCompilationDisabled()) 237 if (!F->isDeclaration() || F->hasNotBeenReadFromBitcode()) 238 TheJIT->addPendingFunction(F); 239 240 return Stub; 241} 242 243/// getGlobalValueIndirectSym - Return a lazy pointer containing the specified 244/// GV address. 245void *JITResolver::getGlobalValueIndirectSym(GlobalValue *GV, void *GVAddress) { 246 MutexGuard locked(TheJIT->lock); 247 248 // If we already have a stub for this global variable, recycle it. 249 void *&IndirectSym = state.getGlobalToIndirectSymMap(locked)[GV]; 250 if (IndirectSym) return IndirectSym; 251 252 // Otherwise, codegen a new indirect symbol. 253 IndirectSym = TheJIT->getJITInfo().emitGlobalValueIndirectSym(GV, GVAddress, 254 *TheJIT->getCodeEmitter()); 255 256 DEBUG(errs() << "JIT: Indirect symbol emitted at [" << IndirectSym 257 << "] for GV '" << GV->getName() << "'\n"); 258 259 return IndirectSym; 260} 261 262/// getExternalFunctionStub - Return a stub for the function at the 263/// specified address, created lazily on demand. 264void *JITResolver::getExternalFunctionStub(void *FnAddr) { 265 // If we already have a stub for this function, recycle it. 266 void *&Stub = ExternalFnToStubMap[FnAddr]; 267 if (Stub) return Stub; 268 269 Stub = TheJIT->getJITInfo().emitFunctionStub(0, FnAddr, 270 *TheJIT->getCodeEmitter()); 271 272 DOUT << "JIT: Stub emitted at [" << Stub 273 << "] for external function at '" << FnAddr << "'\n"; 274 return Stub; 275} 276 277unsigned JITResolver::getGOTIndexForAddr(void* addr) { 278 unsigned idx = revGOTMap[addr]; 279 if (!idx) { 280 idx = ++nextGOTIndex; 281 revGOTMap[addr] = idx; 282 DOUT << "JIT: Adding GOT entry " << idx << " for addr [" << addr << "]\n"; 283 } 284 return idx; 285} 286 287void JITResolver::getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs, 288 SmallVectorImpl<void*> &Ptrs) { 289 MutexGuard locked(TheJIT->lock); 290 291 FunctionToStubMapTy &FM = state.getFunctionToStubMap(locked); 292 GlobalToIndirectSymMapTy &GM = state.getGlobalToIndirectSymMap(locked); 293 294 for (FunctionToStubMapTy::iterator i = FM.begin(), e = FM.end(); i != e; ++i){ 295 Function *F = i->first; 296 if (F->isDeclaration() && F->hasExternalLinkage()) { 297 GVs.push_back(i->first); 298 Ptrs.push_back(i->second); 299 } 300 } 301 for (GlobalToIndirectSymMapTy::iterator i = GM.begin(), e = GM.end(); 302 i != e; ++i) { 303 GVs.push_back(i->first); 304 Ptrs.push_back(i->second); 305 } 306} 307 308GlobalValue *JITResolver::invalidateStub(void *Stub) { 309 MutexGuard locked(TheJIT->lock); 310 311 FunctionToStubMapTy &FM = state.getFunctionToStubMap(locked); 312 StubToFunctionMapTy &SM = state.getStubToFunctionMap(locked); 313 GlobalToIndirectSymMapTy &GM = state.getGlobalToIndirectSymMap(locked); 314 315 // Look up the cheap way first, to see if it's a function stub we are 316 // invalidating. If so, remove it from both the forward and reverse maps. 317 if (SM.find(Stub) != SM.end()) { 318 Function *F = SM[Stub]; 319 SM.erase(Stub); 320 FM.erase(F); 321 return F; 322 } 323 324 // Otherwise, it might be an indirect symbol stub. Find it and remove it. 325 for (GlobalToIndirectSymMapTy::iterator i = GM.begin(), e = GM.end(); 326 i != e; ++i) { 327 if (i->second != Stub) 328 continue; 329 GlobalValue *GV = i->first; 330 GM.erase(i); 331 return GV; 332 } 333 334 // Lastly, check to see if it's in the ExternalFnToStubMap. 335 for (std::map<void *, void *>::iterator i = ExternalFnToStubMap.begin(), 336 e = ExternalFnToStubMap.end(); i != e; ++i) { 337 if (i->second != Stub) 338 continue; 339 ExternalFnToStubMap.erase(i); 340 break; 341 } 342 343 return 0; 344} 345 346/// JITCompilerFn - This function is called when a lazy compilation stub has 347/// been entered. It looks up which function this stub corresponds to, compiles 348/// it if necessary, then returns the resultant function pointer. 349void *JITResolver::JITCompilerFn(void *Stub) { 350 JITResolver &JR = *TheJITResolver; 351 352 Function* F = 0; 353 void* ActualPtr = 0; 354 355 { 356 // Only lock for getting the Function. The call getPointerToFunction made 357 // in this function might trigger function materializing, which requires 358 // JIT lock to be unlocked. 359 MutexGuard locked(TheJIT->lock); 360 361 // The address given to us for the stub may not be exactly right, it might be 362 // a little bit after the stub. As such, use upper_bound to find it. 363 StubToFunctionMapTy::iterator I = 364 JR.state.getStubToFunctionMap(locked).upper_bound(Stub); 365 assert(I != JR.state.getStubToFunctionMap(locked).begin() && 366 "This is not a known stub!"); 367 F = (--I)->second; 368 ActualPtr = I->first; 369 } 370 371 // If we have already code generated the function, just return the address. 372 void *Result = TheJIT->getPointerToGlobalIfAvailable(F); 373 374 if (!Result) { 375 // Otherwise we don't have it, do lazy compilation now. 376 377 // If lazy compilation is disabled, emit a useful error message and abort. 378 if (TheJIT->isLazyCompilationDisabled()) { 379 llvm_report_error("LLVM JIT requested to do lazy compilation of function '" 380 + F->getName() + "' when lazy compiles are disabled!"); 381 } 382 383 // We might like to remove the stub from the StubToFunction map. 384 // We can't do that! Multiple threads could be stuck, waiting to acquire the 385 // lock above. As soon as the 1st function finishes compiling the function, 386 // the next one will be released, and needs to be able to find the function 387 // it needs to call. 388 //JR.state.getStubToFunctionMap(locked).erase(I); 389 390 DEBUG(errs() << "JIT: Lazily resolving function '" << F->getName() 391 << "' In stub ptr = " << Stub << " actual ptr = " 392 << ActualPtr << "\n"); 393 394 Result = TheJIT->getPointerToFunction(F); 395 } 396 397 // Reacquire the lock to erase the stub in the map. 398 MutexGuard locked(TheJIT->lock); 399 400 // We don't need to reuse this stub in the future, as F is now compiled. 401 JR.state.getFunctionToStubMap(locked).erase(F); 402 403 // FIXME: We could rewrite all references to this stub if we knew them. 404 405 // What we will do is set the compiled function address to map to the 406 // same GOT entry as the stub so that later clients may update the GOT 407 // if they see it still using the stub address. 408 // Note: this is done so the Resolver doesn't have to manage GOT memory 409 // Do this without allocating map space if the target isn't using a GOT 410 if(JR.revGOTMap.find(Stub) != JR.revGOTMap.end()) 411 JR.revGOTMap[Result] = JR.revGOTMap[Stub]; 412 413 return Result; 414} 415 416//===----------------------------------------------------------------------===// 417// JITEmitter code. 418// 419namespace { 420 /// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is 421 /// used to output functions to memory for execution. 422 class JITEmitter : public JITCodeEmitter { 423 JITMemoryManager *MemMgr; 424 425 // When outputting a function stub in the context of some other function, we 426 // save BufferBegin/BufferEnd/CurBufferPtr here. 427 uint8_t *SavedBufferBegin, *SavedBufferEnd, *SavedCurBufferPtr; 428 429 // When reattempting to JIT a function after running out of space, we store 430 // the estimated size of the function we're trying to JIT here, so we can 431 // ask the memory manager for at least this much space. When we 432 // successfully emit the function, we reset this back to zero. 433 uintptr_t SizeEstimate; 434 435 /// Relocations - These are the relocations that the function needs, as 436 /// emitted. 437 std::vector<MachineRelocation> Relocations; 438 439 /// MBBLocations - This vector is a mapping from MBB ID's to their address. 440 /// It is filled in by the StartMachineBasicBlock callback and queried by 441 /// the getMachineBasicBlockAddress callback. 442 std::vector<uintptr_t> MBBLocations; 443 444 /// ConstantPool - The constant pool for the current function. 445 /// 446 MachineConstantPool *ConstantPool; 447 448 /// ConstantPoolBase - A pointer to the first entry in the constant pool. 449 /// 450 void *ConstantPoolBase; 451 452 /// ConstPoolAddresses - Addresses of individual constant pool entries. 453 /// 454 SmallVector<uintptr_t, 8> ConstPoolAddresses; 455 456 /// JumpTable - The jump tables for the current function. 457 /// 458 MachineJumpTableInfo *JumpTable; 459 460 /// JumpTableBase - A pointer to the first entry in the jump table. 461 /// 462 void *JumpTableBase; 463 464 /// Resolver - This contains info about the currently resolved functions. 465 JITResolver Resolver; 466 467 /// DE - The dwarf emitter for the jit. 468 JITDwarfEmitter *DE; 469 470 /// LabelLocations - This vector is a mapping from Label ID's to their 471 /// address. 472 std::vector<uintptr_t> LabelLocations; 473 474 /// MMI - Machine module info for exception informations 475 MachineModuleInfo* MMI; 476 477 // GVSet - a set to keep track of which globals have been seen 478 SmallPtrSet<const GlobalVariable*, 8> GVSet; 479 480 // CurFn - The llvm function being emitted. Only valid during 481 // finishFunction(). 482 const Function *CurFn; 483 484 /// Information about emitted code, which is passed to the 485 /// JITEventListeners. This is reset in startFunction and used in 486 /// finishFunction. 487 JITEvent_EmittedFunctionDetails EmissionDetails; 488 489 // CurFnStubUses - For a given Function, a vector of stubs that it 490 // references. This facilitates the JIT detecting that a stub is no 491 // longer used, so that it may be deallocated. 492 DenseMap<const Function *, SmallVector<void*, 1> > CurFnStubUses; 493 494 // StubFnRefs - For a given pointer to a stub, a set of Functions which 495 // reference the stub. When the count of a stub's references drops to zero, 496 // the stub is unused. 497 DenseMap<void *, SmallPtrSet<const Function*, 1> > StubFnRefs; 498 499 // ExtFnStubs - A map of external function names to stubs which have entries 500 // in the JITResolver's ExternalFnToStubMap. 501 StringMap<void *> ExtFnStubs; 502 503 DebugLocTuple PrevDLT; 504 505 public: 506 JITEmitter(JIT &jit, JITMemoryManager *JMM) 507 : SizeEstimate(0), Resolver(jit), CurFn(0) { 508 MemMgr = JMM ? JMM : JITMemoryManager::CreateDefaultMemManager(); 509 if (jit.getJITInfo().needsGOT()) { 510 MemMgr->AllocateGOT(); 511 DOUT << "JIT is managing a GOT\n"; 512 } 513 514 if (DwarfExceptionHandling) DE = new JITDwarfEmitter(jit); 515 } 516 ~JITEmitter() { 517 delete MemMgr; 518 if (DwarfExceptionHandling) delete DE; 519 } 520 521 /// classof - Methods for support type inquiry through isa, cast, and 522 /// dyn_cast: 523 /// 524 static inline bool classof(const JITEmitter*) { return true; } 525 static inline bool classof(const MachineCodeEmitter*) { return true; } 526 527 JITResolver &getJITResolver() { return Resolver; } 528 529 virtual void startFunction(MachineFunction &F); 530 virtual bool finishFunction(MachineFunction &F); 531 532 void emitConstantPool(MachineConstantPool *MCP); 533 void initJumpTableInfo(MachineJumpTableInfo *MJTI); 534 void emitJumpTableInfo(MachineJumpTableInfo *MJTI); 535 536 virtual void startGVStub(const GlobalValue* GV, unsigned StubSize, 537 unsigned Alignment = 1); 538 virtual void startGVStub(const GlobalValue* GV, void *Buffer, 539 unsigned StubSize); 540 virtual void* finishGVStub(const GlobalValue *GV); 541 542 /// allocateSpace - Reserves space in the current block if any, or 543 /// allocate a new one of the given size. 544 virtual void *allocateSpace(uintptr_t Size, unsigned Alignment); 545 546 /// allocateGlobal - Allocate memory for a global. Unlike allocateSpace, 547 /// this method does not allocate memory in the current output buffer, 548 /// because a global may live longer than the current function. 549 virtual void *allocateGlobal(uintptr_t Size, unsigned Alignment); 550 551 virtual void addRelocation(const MachineRelocation &MR) { 552 Relocations.push_back(MR); 553 } 554 555 virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) { 556 if (MBBLocations.size() <= (unsigned)MBB->getNumber()) 557 MBBLocations.resize((MBB->getNumber()+1)*2); 558 MBBLocations[MBB->getNumber()] = getCurrentPCValue(); 559 DOUT << "JIT: Emitting BB" << MBB->getNumber() << " at [" 560 << (void*) getCurrentPCValue() << "]\n"; 561 } 562 563 virtual uintptr_t getConstantPoolEntryAddress(unsigned Entry) const; 564 virtual uintptr_t getJumpTableEntryAddress(unsigned Entry) const; 565 566 virtual uintptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const { 567 assert(MBBLocations.size() > (unsigned)MBB->getNumber() && 568 MBBLocations[MBB->getNumber()] && "MBB not emitted!"); 569 return MBBLocations[MBB->getNumber()]; 570 } 571 572 /// retryWithMoreMemory - Log a retry and deallocate all memory for the 573 /// given function. Increase the minimum allocation size so that we get 574 /// more memory next time. 575 void retryWithMoreMemory(MachineFunction &F); 576 577 /// deallocateMemForFunction - Deallocate all memory for the specified 578 /// function body. 579 void deallocateMemForFunction(const Function *F); 580 581 /// AddStubToCurrentFunction - Mark the current function being JIT'd as 582 /// using the stub at the specified address. Allows 583 /// deallocateMemForFunction to also remove stubs no longer referenced. 584 void AddStubToCurrentFunction(void *Stub); 585 586 /// getExternalFnStubs - Accessor for the JIT to find stubs emitted for 587 /// MachineRelocations that reference external functions by name. 588 const StringMap<void*> &getExternalFnStubs() const { return ExtFnStubs; } 589 590 virtual void processDebugLoc(DebugLoc DL); 591 592 virtual void emitLabel(uint64_t LabelID) { 593 if (LabelLocations.size() <= LabelID) 594 LabelLocations.resize((LabelID+1)*2); 595 LabelLocations[LabelID] = getCurrentPCValue(); 596 } 597 598 virtual uintptr_t getLabelAddress(uint64_t LabelID) const { 599 assert(LabelLocations.size() > (unsigned)LabelID && 600 LabelLocations[LabelID] && "Label not emitted!"); 601 return LabelLocations[LabelID]; 602 } 603 604 virtual void setModuleInfo(MachineModuleInfo* Info) { 605 MMI = Info; 606 if (DwarfExceptionHandling) DE->setModuleInfo(Info); 607 } 608 609 void setMemoryExecutable(void) { 610 MemMgr->setMemoryExecutable(); 611 } 612 613 JITMemoryManager *getMemMgr(void) const { return MemMgr; } 614 615 private: 616 void *getPointerToGlobal(GlobalValue *GV, void *Reference, bool NoNeedStub); 617 void *getPointerToGVIndirectSym(GlobalValue *V, void *Reference, 618 bool NoNeedStub); 619 unsigned addSizeOfGlobal(const GlobalVariable *GV, unsigned Size); 620 unsigned addSizeOfGlobalsInConstantVal(const Constant *C, unsigned Size); 621 unsigned addSizeOfGlobalsInInitializer(const Constant *Init, unsigned Size); 622 unsigned GetSizeOfGlobalsInBytes(MachineFunction &MF); 623 }; 624} 625 626void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference, 627 bool DoesntNeedStub) { 628 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) 629 return TheJIT->getOrEmitGlobalVariable(GV); 630 631 if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) 632 return TheJIT->getPointerToGlobal(GA->resolveAliasedGlobal(false)); 633 634 // If we have already compiled the function, return a pointer to its body. 635 Function *F = cast<Function>(V); 636 void *ResultPtr; 637 if (!DoesntNeedStub && !TheJIT->isLazyCompilationDisabled()) { 638 // Return the function stub if it's already created. 639 ResultPtr = Resolver.getFunctionStubIfAvailable(F); 640 if (ResultPtr) 641 AddStubToCurrentFunction(ResultPtr); 642 } else { 643 ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F); 644 } 645 if (ResultPtr) return ResultPtr; 646 647 // If this is an external function pointer, we can force the JIT to 648 // 'compile' it, which really just adds it to the map. In dlsym mode, 649 // external functions are forced through a stub, regardless of reloc type. 650 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode() && 651 DoesntNeedStub && !TheJIT->areDlsymStubsEnabled()) 652 return TheJIT->getPointerToFunction(F); 653 654 // Okay, the function has not been compiled yet, if the target callback 655 // mechanism is capable of rewriting the instruction directly, prefer to do 656 // that instead of emitting a stub. This uses the lazy resolver, so is not 657 // legal if lazy compilation is disabled. 658 if (DoesntNeedStub && !TheJIT->isLazyCompilationDisabled()) 659 return Resolver.AddCallbackAtLocation(F, Reference); 660 661 // Otherwise, we have to emit a stub. 662 void *StubAddr = Resolver.getFunctionStub(F); 663 664 // Add the stub to the current function's list of referenced stubs, so we can 665 // deallocate them if the current function is ever freed. It's possible to 666 // return null from getFunctionStub in the case of a weak extern that fails 667 // to resolve. 668 if (StubAddr) 669 AddStubToCurrentFunction(StubAddr); 670 671 return StubAddr; 672} 673 674void *JITEmitter::getPointerToGVIndirectSym(GlobalValue *V, void *Reference, 675 bool NoNeedStub) { 676 // Make sure GV is emitted first, and create a stub containing the fully 677 // resolved address. 678 void *GVAddress = getPointerToGlobal(V, Reference, true); 679 void *StubAddr = Resolver.getGlobalValueIndirectSym(V, GVAddress); 680 681 // Add the stub to the current function's list of referenced stubs, so we can 682 // deallocate them if the current function is ever freed. 683 AddStubToCurrentFunction(StubAddr); 684 685 return StubAddr; 686} 687 688void JITEmitter::AddStubToCurrentFunction(void *StubAddr) { 689 if (!TheJIT->areDlsymStubsEnabled()) 690 return; 691 692 assert(CurFn && "Stub added to current function, but current function is 0!"); 693 694 SmallVectorImpl<void*> &StubsUsed = CurFnStubUses[CurFn]; 695 StubsUsed.push_back(StubAddr); 696 697 SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[StubAddr]; 698 FnRefs.insert(CurFn); 699} 700 701void JITEmitter::processDebugLoc(DebugLoc DL) { 702 if (!DL.isUnknown()) { 703 DebugLocTuple CurDLT = EmissionDetails.MF->getDebugLocTuple(DL); 704 705 if (CurDLT.CompileUnit != 0 && PrevDLT != CurDLT) { 706 JITEvent_EmittedFunctionDetails::LineStart NextLine; 707 NextLine.Address = getCurrentPCValue(); 708 NextLine.Loc = DL; 709 EmissionDetails.LineStarts.push_back(NextLine); 710 } 711 712 PrevDLT = CurDLT; 713 } 714} 715 716static unsigned GetConstantPoolSizeInBytes(MachineConstantPool *MCP, 717 const TargetData *TD) { 718 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants(); 719 if (Constants.empty()) return 0; 720 721 unsigned Size = 0; 722 for (unsigned i = 0, e = Constants.size(); i != e; ++i) { 723 MachineConstantPoolEntry CPE = Constants[i]; 724 unsigned AlignMask = CPE.getAlignment() - 1; 725 Size = (Size + AlignMask) & ~AlignMask; 726 const Type *Ty = CPE.getType(); 727 Size += TD->getTypeAllocSize(Ty); 728 } 729 return Size; 730} 731 732static unsigned GetJumpTableSizeInBytes(MachineJumpTableInfo *MJTI) { 733 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables(); 734 if (JT.empty()) return 0; 735 736 unsigned NumEntries = 0; 737 for (unsigned i = 0, e = JT.size(); i != e; ++i) 738 NumEntries += JT[i].MBBs.size(); 739 740 unsigned EntrySize = MJTI->getEntrySize(); 741 742 return NumEntries * EntrySize; 743} 744 745static uintptr_t RoundUpToAlign(uintptr_t Size, unsigned Alignment) { 746 if (Alignment == 0) Alignment = 1; 747 // Since we do not know where the buffer will be allocated, be pessimistic. 748 return Size + Alignment; 749} 750 751/// addSizeOfGlobal - add the size of the global (plus any alignment padding) 752/// into the running total Size. 753 754unsigned JITEmitter::addSizeOfGlobal(const GlobalVariable *GV, unsigned Size) { 755 const Type *ElTy = GV->getType()->getElementType(); 756 size_t GVSize = (size_t)TheJIT->getTargetData()->getTypeAllocSize(ElTy); 757 size_t GVAlign = 758 (size_t)TheJIT->getTargetData()->getPreferredAlignment(GV); 759 DOUT << "JIT: Adding in size " << GVSize << " alignment " << GVAlign; 760 DEBUG(GV->dump()); 761 // Assume code section ends with worst possible alignment, so first 762 // variable needs maximal padding. 763 if (Size==0) 764 Size = 1; 765 Size = ((Size+GVAlign-1)/GVAlign)*GVAlign; 766 Size += GVSize; 767 return Size; 768} 769 770/// addSizeOfGlobalsInConstantVal - find any globals that we haven't seen yet 771/// but are referenced from the constant; put them in GVSet and add their 772/// size into the running total Size. 773 774unsigned JITEmitter::addSizeOfGlobalsInConstantVal(const Constant *C, 775 unsigned Size) { 776 // If its undefined, return the garbage. 777 if (isa<UndefValue>(C)) 778 return Size; 779 780 // If the value is a ConstantExpr 781 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) { 782 Constant *Op0 = CE->getOperand(0); 783 switch (CE->getOpcode()) { 784 case Instruction::GetElementPtr: 785 case Instruction::Trunc: 786 case Instruction::ZExt: 787 case Instruction::SExt: 788 case Instruction::FPTrunc: 789 case Instruction::FPExt: 790 case Instruction::UIToFP: 791 case Instruction::SIToFP: 792 case Instruction::FPToUI: 793 case Instruction::FPToSI: 794 case Instruction::PtrToInt: 795 case Instruction::IntToPtr: 796 case Instruction::BitCast: { 797 Size = addSizeOfGlobalsInConstantVal(Op0, Size); 798 break; 799 } 800 case Instruction::Add: 801 case Instruction::FAdd: 802 case Instruction::Sub: 803 case Instruction::FSub: 804 case Instruction::Mul: 805 case Instruction::FMul: 806 case Instruction::UDiv: 807 case Instruction::SDiv: 808 case Instruction::URem: 809 case Instruction::SRem: 810 case Instruction::And: 811 case Instruction::Or: 812 case Instruction::Xor: { 813 Size = addSizeOfGlobalsInConstantVal(Op0, Size); 814 Size = addSizeOfGlobalsInConstantVal(CE->getOperand(1), Size); 815 break; 816 } 817 default: { 818 std::string msg; 819 raw_string_ostream Msg(msg); 820 Msg << "ConstantExpr not handled: " << *CE; 821 llvm_report_error(Msg.str()); 822 } 823 } 824 } 825 826 if (C->getType()->getTypeID() == Type::PointerTyID) 827 if (const GlobalVariable* GV = dyn_cast<GlobalVariable>(C)) 828 if (GVSet.insert(GV)) 829 Size = addSizeOfGlobal(GV, Size); 830 831 return Size; 832} 833 834/// addSizeOfGLobalsInInitializer - handle any globals that we haven't seen yet 835/// but are referenced from the given initializer. 836 837unsigned JITEmitter::addSizeOfGlobalsInInitializer(const Constant *Init, 838 unsigned Size) { 839 if (!isa<UndefValue>(Init) && 840 !isa<ConstantVector>(Init) && 841 !isa<ConstantAggregateZero>(Init) && 842 !isa<ConstantArray>(Init) && 843 !isa<ConstantStruct>(Init) && 844 Init->getType()->isFirstClassType()) 845 Size = addSizeOfGlobalsInConstantVal(Init, Size); 846 return Size; 847} 848 849/// GetSizeOfGlobalsInBytes - walk the code for the function, looking for 850/// globals; then walk the initializers of those globals looking for more. 851/// If their size has not been considered yet, add it into the running total 852/// Size. 853 854unsigned JITEmitter::GetSizeOfGlobalsInBytes(MachineFunction &MF) { 855 unsigned Size = 0; 856 GVSet.clear(); 857 858 for (MachineFunction::iterator MBB = MF.begin(), E = MF.end(); 859 MBB != E; ++MBB) { 860 for (MachineBasicBlock::const_iterator I = MBB->begin(), E = MBB->end(); 861 I != E; ++I) { 862 const TargetInstrDesc &Desc = I->getDesc(); 863 const MachineInstr &MI = *I; 864 unsigned NumOps = Desc.getNumOperands(); 865 for (unsigned CurOp = 0; CurOp < NumOps; CurOp++) { 866 const MachineOperand &MO = MI.getOperand(CurOp); 867 if (MO.isGlobal()) { 868 GlobalValue* V = MO.getGlobal(); 869 const GlobalVariable *GV = dyn_cast<const GlobalVariable>(V); 870 if (!GV) 871 continue; 872 // If seen in previous function, it will have an entry here. 873 if (TheJIT->getPointerToGlobalIfAvailable(GV)) 874 continue; 875 // If seen earlier in this function, it will have an entry here. 876 // FIXME: it should be possible to combine these tables, by 877 // assuming the addresses of the new globals in this module 878 // start at 0 (or something) and adjusting them after codegen 879 // complete. Another possibility is to grab a marker bit in GV. 880 if (GVSet.insert(GV)) 881 // A variable as yet unseen. Add in its size. 882 Size = addSizeOfGlobal(GV, Size); 883 } 884 } 885 } 886 } 887 DOUT << "JIT: About to look through initializers\n"; 888 // Look for more globals that are referenced only from initializers. 889 // GVSet.end is computed each time because the set can grow as we go. 890 for (SmallPtrSet<const GlobalVariable *, 8>::iterator I = GVSet.begin(); 891 I != GVSet.end(); I++) { 892 const GlobalVariable* GV = *I; 893 if (GV->hasInitializer()) 894 Size = addSizeOfGlobalsInInitializer(GV->getInitializer(), Size); 895 } 896 897 return Size; 898} 899 900void JITEmitter::startFunction(MachineFunction &F) { 901 DEBUG(errs() << "JIT: Starting CodeGen of Function " 902 << F.getFunction()->getName() << "\n"); 903 904 uintptr_t ActualSize = 0; 905 // Set the memory writable, if it's not already 906 MemMgr->setMemoryWritable(); 907 if (MemMgr->NeedsExactSize()) { 908 DOUT << "JIT: ExactSize\n"; 909 const TargetInstrInfo* TII = F.getTarget().getInstrInfo(); 910 MachineJumpTableInfo *MJTI = F.getJumpTableInfo(); 911 MachineConstantPool *MCP = F.getConstantPool(); 912 913 // Ensure the constant pool/jump table info is at least 4-byte aligned. 914 ActualSize = RoundUpToAlign(ActualSize, 16); 915 916 // Add the alignment of the constant pool 917 ActualSize = RoundUpToAlign(ActualSize, MCP->getConstantPoolAlignment()); 918 919 // Add the constant pool size 920 ActualSize += GetConstantPoolSizeInBytes(MCP, TheJIT->getTargetData()); 921 922 // Add the aligment of the jump table info 923 ActualSize = RoundUpToAlign(ActualSize, MJTI->getAlignment()); 924 925 // Add the jump table size 926 ActualSize += GetJumpTableSizeInBytes(MJTI); 927 928 // Add the alignment for the function 929 ActualSize = RoundUpToAlign(ActualSize, 930 std::max(F.getFunction()->getAlignment(), 8U)); 931 932 // Add the function size 933 ActualSize += TII->GetFunctionSizeInBytes(F); 934 935 DOUT << "JIT: ActualSize before globals " << ActualSize << "\n"; 936 // Add the size of the globals that will be allocated after this function. 937 // These are all the ones referenced from this function that were not 938 // previously allocated. 939 ActualSize += GetSizeOfGlobalsInBytes(F); 940 DOUT << "JIT: ActualSize after globals " << ActualSize << "\n"; 941 } else if (SizeEstimate > 0) { 942 // SizeEstimate will be non-zero on reallocation attempts. 943 ActualSize = SizeEstimate; 944 } 945 946 BufferBegin = CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(), 947 ActualSize); 948 BufferEnd = BufferBegin+ActualSize; 949 950 // Ensure the constant pool/jump table info is at least 4-byte aligned. 951 emitAlignment(16); 952 953 emitConstantPool(F.getConstantPool()); 954 initJumpTableInfo(F.getJumpTableInfo()); 955 956 // About to start emitting the machine code for the function. 957 emitAlignment(std::max(F.getFunction()->getAlignment(), 8U)); 958 TheJIT->updateGlobalMapping(F.getFunction(), CurBufferPtr); 959 960 MBBLocations.clear(); 961 962 EmissionDetails.MF = &F; 963 EmissionDetails.LineStarts.clear(); 964} 965 966bool JITEmitter::finishFunction(MachineFunction &F) { 967 if (CurBufferPtr == BufferEnd) { 968 // We must call endFunctionBody before retrying, because 969 // deallocateMemForFunction requires it. 970 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, CurBufferPtr); 971 retryWithMoreMemory(F); 972 return true; 973 } 974 975 emitJumpTableInfo(F.getJumpTableInfo()); 976 977 // FnStart is the start of the text, not the start of the constant pool and 978 // other per-function data. 979 uint8_t *FnStart = 980 (uint8_t *)TheJIT->getPointerToGlobalIfAvailable(F.getFunction()); 981 982 // FnEnd is the end of the function's machine code. 983 uint8_t *FnEnd = CurBufferPtr; 984 985 if (!Relocations.empty()) { 986 CurFn = F.getFunction(); 987 NumRelos += Relocations.size(); 988 989 // Resolve the relocations to concrete pointers. 990 for (unsigned i = 0, e = Relocations.size(); i != e; ++i) { 991 MachineRelocation &MR = Relocations[i]; 992 void *ResultPtr = 0; 993 if (!MR.letTargetResolve()) { 994 if (MR.isExternalSymbol()) { 995 ResultPtr = TheJIT->getPointerToNamedFunction(MR.getExternalSymbol(), 996 false); 997 DOUT << "JIT: Map \'" << MR.getExternalSymbol() << "\' to [" 998 << ResultPtr << "]\n"; 999 1000 // If the target REALLY wants a stub for this function, emit it now. 1001 if (!MR.doesntNeedStub()) { 1002 if (!TheJIT->areDlsymStubsEnabled()) { 1003 ResultPtr = Resolver.getExternalFunctionStub(ResultPtr); 1004 } else { 1005 void *&Stub = ExtFnStubs[MR.getExternalSymbol()]; 1006 if (!Stub) { 1007 Stub = Resolver.getExternalFunctionStub((void *)&Stub); 1008 AddStubToCurrentFunction(Stub); 1009 } 1010 ResultPtr = Stub; 1011 } 1012 } 1013 } else if (MR.isGlobalValue()) { 1014 ResultPtr = getPointerToGlobal(MR.getGlobalValue(), 1015 BufferBegin+MR.getMachineCodeOffset(), 1016 MR.doesntNeedStub()); 1017 } else if (MR.isIndirectSymbol()) { 1018 ResultPtr = getPointerToGVIndirectSym(MR.getGlobalValue(), 1019 BufferBegin+MR.getMachineCodeOffset(), 1020 MR.doesntNeedStub()); 1021 } else if (MR.isBasicBlock()) { 1022 ResultPtr = (void*)getMachineBasicBlockAddress(MR.getBasicBlock()); 1023 } else if (MR.isConstantPoolIndex()) { 1024 ResultPtr = (void*)getConstantPoolEntryAddress(MR.getConstantPoolIndex()); 1025 } else { 1026 assert(MR.isJumpTableIndex()); 1027 ResultPtr=(void*)getJumpTableEntryAddress(MR.getJumpTableIndex()); 1028 } 1029 1030 MR.setResultPointer(ResultPtr); 1031 } 1032 1033 // if we are managing the GOT and the relocation wants an index, 1034 // give it one 1035 if (MR.isGOTRelative() && MemMgr->isManagingGOT()) { 1036 unsigned idx = Resolver.getGOTIndexForAddr(ResultPtr); 1037 MR.setGOTIndex(idx); 1038 if (((void**)MemMgr->getGOTBase())[idx] != ResultPtr) { 1039 DOUT << "JIT: GOT was out of date for " << ResultPtr 1040 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx] 1041 << "\n"; 1042 ((void**)MemMgr->getGOTBase())[idx] = ResultPtr; 1043 } 1044 } 1045 } 1046 1047 CurFn = 0; 1048 TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0], 1049 Relocations.size(), MemMgr->getGOTBase()); 1050 } 1051 1052 // Update the GOT entry for F to point to the new code. 1053 if (MemMgr->isManagingGOT()) { 1054 unsigned idx = Resolver.getGOTIndexForAddr((void*)BufferBegin); 1055 if (((void**)MemMgr->getGOTBase())[idx] != (void*)BufferBegin) { 1056 DOUT << "JIT: GOT was out of date for " << (void*)BufferBegin 1057 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx] << "\n"; 1058 ((void**)MemMgr->getGOTBase())[idx] = (void*)BufferBegin; 1059 } 1060 } 1061 1062 // CurBufferPtr may have moved beyond FnEnd, due to memory allocation for 1063 // global variables that were referenced in the relocations. 1064 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, CurBufferPtr); 1065 1066 if (CurBufferPtr == BufferEnd) { 1067 retryWithMoreMemory(F); 1068 return true; 1069 } else { 1070 // Now that we've succeeded in emitting the function, reset the 1071 // SizeEstimate back down to zero. 1072 SizeEstimate = 0; 1073 } 1074 1075 BufferBegin = CurBufferPtr = 0; 1076 NumBytes += FnEnd-FnStart; 1077 1078 // Invalidate the icache if necessary. 1079 sys::Memory::InvalidateInstructionCache(FnStart, FnEnd-FnStart); 1080 1081 TheJIT->NotifyFunctionEmitted(*F.getFunction(), FnStart, FnEnd-FnStart, 1082 EmissionDetails); 1083 1084 DEBUG(errs() << "JIT: Finished CodeGen of [" << (void*)FnStart 1085 << "] Function: " << F.getFunction()->getName() 1086 << ": " << (FnEnd-FnStart) << " bytes of text, " 1087 << Relocations.size() << " relocations\n"); 1088 1089 Relocations.clear(); 1090 ConstPoolAddresses.clear(); 1091 1092 // Mark code region readable and executable if it's not so already. 1093 MemMgr->setMemoryExecutable(); 1094 1095#ifndef NDEBUG 1096 { 1097 if (sys::hasDisassembler()) { 1098 DOUT << "JIT: Disassembled code:\n"; 1099 DOUT << sys::disassembleBuffer(FnStart, FnEnd-FnStart, (uintptr_t)FnStart); 1100 } else { 1101 DOUT << "JIT: Binary code:\n"; 1102 DOUT << std::hex; 1103 uint8_t* q = FnStart; 1104 for (int i = 0; q < FnEnd; q += 4, ++i) { 1105 if (i == 4) 1106 i = 0; 1107 if (i == 0) 1108 DOUT << "JIT: " << std::setw(8) << std::setfill('0') 1109 << (long)(q - FnStart) << ": "; 1110 bool Done = false; 1111 for (int j = 3; j >= 0; --j) { 1112 if (q + j >= FnEnd) 1113 Done = true; 1114 else 1115 DOUT << std::setw(2) << std::setfill('0') << (unsigned short)q[j]; 1116 } 1117 if (Done) 1118 break; 1119 DOUT << ' '; 1120 if (i == 3) 1121 DOUT << '\n'; 1122 } 1123 DOUT << std::dec; 1124 DOUT<< '\n'; 1125 } 1126 } 1127#endif 1128 if (DwarfExceptionHandling) { 1129 uintptr_t ActualSize = 0; 1130 SavedBufferBegin = BufferBegin; 1131 SavedBufferEnd = BufferEnd; 1132 SavedCurBufferPtr = CurBufferPtr; 1133 1134 if (MemMgr->NeedsExactSize()) { 1135 ActualSize = DE->GetDwarfTableSizeInBytes(F, *this, FnStart, FnEnd); 1136 } 1137 1138 BufferBegin = CurBufferPtr = MemMgr->startExceptionTable(F.getFunction(), 1139 ActualSize); 1140 BufferEnd = BufferBegin+ActualSize; 1141 uint8_t* FrameRegister = DE->EmitDwarfTable(F, *this, FnStart, FnEnd); 1142 MemMgr->endExceptionTable(F.getFunction(), BufferBegin, CurBufferPtr, 1143 FrameRegister); 1144 BufferBegin = SavedBufferBegin; 1145 BufferEnd = SavedBufferEnd; 1146 CurBufferPtr = SavedCurBufferPtr; 1147 1148 TheJIT->RegisterTable(FrameRegister); 1149 } 1150 1151 if (MMI) 1152 MMI->EndFunction(); 1153 1154 return false; 1155} 1156 1157void JITEmitter::retryWithMoreMemory(MachineFunction &F) { 1158 DOUT << "JIT: Ran out of space for native code. Reattempting.\n"; 1159 Relocations.clear(); // Clear the old relocations or we'll reapply them. 1160 ConstPoolAddresses.clear(); 1161 ++NumRetries; 1162 deallocateMemForFunction(F.getFunction()); 1163 // Try again with at least twice as much free space. 1164 SizeEstimate = (uintptr_t)(2 * (BufferEnd - BufferBegin)); 1165} 1166 1167/// deallocateMemForFunction - Deallocate all memory for the specified 1168/// function body. Also drop any references the function has to stubs. 1169void JITEmitter::deallocateMemForFunction(const Function *F) { 1170 MemMgr->deallocateMemForFunction(F); 1171 1172 // If the function did not reference any stubs, return. 1173 if (CurFnStubUses.find(F) == CurFnStubUses.end()) 1174 return; 1175 1176 // For each referenced stub, erase the reference to this function, and then 1177 // erase the list of referenced stubs. 1178 SmallVectorImpl<void *> &StubList = CurFnStubUses[F]; 1179 for (unsigned i = 0, e = StubList.size(); i != e; ++i) { 1180 void *Stub = StubList[i]; 1181 1182 // If we already invalidated this stub for this function, continue. 1183 if (StubFnRefs.count(Stub) == 0) 1184 continue; 1185 1186 SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[Stub]; 1187 FnRefs.erase(F); 1188 1189 // If this function was the last reference to the stub, invalidate the stub 1190 // in the JITResolver. Were there a memory manager deallocateStub routine, 1191 // we could call that at this point too. 1192 if (FnRefs.empty()) { 1193 DOUT << "\nJIT: Invalidated Stub at [" << Stub << "]\n"; 1194 StubFnRefs.erase(Stub); 1195 1196 // Invalidate the stub. If it is a GV stub, update the JIT's global 1197 // mapping for that GV to zero, otherwise, search the string map of 1198 // external function names to stubs and remove the entry for this stub. 1199 GlobalValue *GV = Resolver.invalidateStub(Stub); 1200 if (GV) { 1201 TheJIT->updateGlobalMapping(GV, 0); 1202 } else { 1203 for (StringMapIterator<void*> i = ExtFnStubs.begin(), 1204 e = ExtFnStubs.end(); i != e; ++i) { 1205 if (i->second == Stub) { 1206 ExtFnStubs.erase(i); 1207 break; 1208 } 1209 } 1210 } 1211 } 1212 } 1213 CurFnStubUses.erase(F); 1214} 1215 1216 1217void* JITEmitter::allocateSpace(uintptr_t Size, unsigned Alignment) { 1218 if (BufferBegin) 1219 return JITCodeEmitter::allocateSpace(Size, Alignment); 1220 1221 // create a new memory block if there is no active one. 1222 // care must be taken so that BufferBegin is invalidated when a 1223 // block is trimmed 1224 BufferBegin = CurBufferPtr = MemMgr->allocateSpace(Size, Alignment); 1225 BufferEnd = BufferBegin+Size; 1226 return CurBufferPtr; 1227} 1228 1229void* JITEmitter::allocateGlobal(uintptr_t Size, unsigned Alignment) { 1230 // Delegate this call through the memory manager. 1231 return MemMgr->allocateGlobal(Size, Alignment); 1232} 1233 1234void JITEmitter::emitConstantPool(MachineConstantPool *MCP) { 1235 if (TheJIT->getJITInfo().hasCustomConstantPool()) 1236 return; 1237 1238 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants(); 1239 if (Constants.empty()) return; 1240 1241 unsigned Size = GetConstantPoolSizeInBytes(MCP, TheJIT->getTargetData()); 1242 unsigned Align = MCP->getConstantPoolAlignment(); 1243 ConstantPoolBase = allocateSpace(Size, Align); 1244 ConstantPool = MCP; 1245 1246 if (ConstantPoolBase == 0) return; // Buffer overflow. 1247 1248 DOUT << "JIT: Emitted constant pool at [" << ConstantPoolBase 1249 << "] (size: " << Size << ", alignment: " << Align << ")\n"; 1250 1251 // Initialize the memory for all of the constant pool entries. 1252 unsigned Offset = 0; 1253 for (unsigned i = 0, e = Constants.size(); i != e; ++i) { 1254 MachineConstantPoolEntry CPE = Constants[i]; 1255 unsigned AlignMask = CPE.getAlignment() - 1; 1256 Offset = (Offset + AlignMask) & ~AlignMask; 1257 1258 uintptr_t CAddr = (uintptr_t)ConstantPoolBase + Offset; 1259 ConstPoolAddresses.push_back(CAddr); 1260 if (CPE.isMachineConstantPoolEntry()) { 1261 // FIXME: add support to lower machine constant pool values into bytes! 1262 llvm_report_error("Initialize memory with machine specific constant pool" 1263 "entry has not been implemented!"); 1264 } 1265 TheJIT->InitializeMemory(CPE.Val.ConstVal, (void*)CAddr); 1266 DOUT << "JIT: CP" << i << " at [0x" 1267 << std::hex << CAddr << std::dec << "]\n"; 1268 1269 const Type *Ty = CPE.Val.ConstVal->getType(); 1270 Offset += TheJIT->getTargetData()->getTypeAllocSize(Ty); 1271 } 1272} 1273 1274void JITEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) { 1275 if (TheJIT->getJITInfo().hasCustomJumpTables()) 1276 return; 1277 1278 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables(); 1279 if (JT.empty()) return; 1280 1281 unsigned NumEntries = 0; 1282 for (unsigned i = 0, e = JT.size(); i != e; ++i) 1283 NumEntries += JT[i].MBBs.size(); 1284 1285 unsigned EntrySize = MJTI->getEntrySize(); 1286 1287 // Just allocate space for all the jump tables now. We will fix up the actual 1288 // MBB entries in the tables after we emit the code for each block, since then 1289 // we will know the final locations of the MBBs in memory. 1290 JumpTable = MJTI; 1291 JumpTableBase = allocateSpace(NumEntries * EntrySize, MJTI->getAlignment()); 1292} 1293 1294void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) { 1295 if (TheJIT->getJITInfo().hasCustomJumpTables()) 1296 return; 1297 1298 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables(); 1299 if (JT.empty() || JumpTableBase == 0) return; 1300 1301 if (TargetMachine::getRelocationModel() == Reloc::PIC_) { 1302 assert(MJTI->getEntrySize() == 4 && "Cross JIT'ing?"); 1303 // For each jump table, place the offset from the beginning of the table 1304 // to the target address. 1305 int *SlotPtr = (int*)JumpTableBase; 1306 1307 for (unsigned i = 0, e = JT.size(); i != e; ++i) { 1308 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs; 1309 // Store the offset of the basic block for this jump table slot in the 1310 // memory we allocated for the jump table in 'initJumpTableInfo' 1311 uintptr_t Base = (uintptr_t)SlotPtr; 1312 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) { 1313 uintptr_t MBBAddr = getMachineBasicBlockAddress(MBBs[mi]); 1314 *SlotPtr++ = TheJIT->getJITInfo().getPICJumpTableEntry(MBBAddr, Base); 1315 } 1316 } 1317 } else { 1318 assert(MJTI->getEntrySize() == sizeof(void*) && "Cross JIT'ing?"); 1319 1320 // For each jump table, map each target in the jump table to the address of 1321 // an emitted MachineBasicBlock. 1322 intptr_t *SlotPtr = (intptr_t*)JumpTableBase; 1323 1324 for (unsigned i = 0, e = JT.size(); i != e; ++i) { 1325 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs; 1326 // Store the address of the basic block for this jump table slot in the 1327 // memory we allocated for the jump table in 'initJumpTableInfo' 1328 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) 1329 *SlotPtr++ = getMachineBasicBlockAddress(MBBs[mi]); 1330 } 1331 } 1332} 1333 1334void JITEmitter::startGVStub(const GlobalValue* GV, unsigned StubSize, 1335 unsigned Alignment) { 1336 SavedBufferBegin = BufferBegin; 1337 SavedBufferEnd = BufferEnd; 1338 SavedCurBufferPtr = CurBufferPtr; 1339 1340 BufferBegin = CurBufferPtr = MemMgr->allocateStub(GV, StubSize, Alignment); 1341 BufferEnd = BufferBegin+StubSize+1; 1342} 1343 1344void JITEmitter::startGVStub(const GlobalValue* GV, void *Buffer, 1345 unsigned StubSize) { 1346 SavedBufferBegin = BufferBegin; 1347 SavedBufferEnd = BufferEnd; 1348 SavedCurBufferPtr = CurBufferPtr; 1349 1350 BufferBegin = CurBufferPtr = (uint8_t *)Buffer; 1351 BufferEnd = BufferBegin+StubSize+1; 1352} 1353 1354void *JITEmitter::finishGVStub(const GlobalValue* GV) { 1355 NumBytes += getCurrentPCOffset(); 1356 std::swap(SavedBufferBegin, BufferBegin); 1357 BufferEnd = SavedBufferEnd; 1358 CurBufferPtr = SavedCurBufferPtr; 1359 return SavedBufferBegin; 1360} 1361 1362// getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry 1363// in the constant pool that was last emitted with the 'emitConstantPool' 1364// method. 1365// 1366uintptr_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) const { 1367 assert(ConstantNum < ConstantPool->getConstants().size() && 1368 "Invalid ConstantPoolIndex!"); 1369 return ConstPoolAddresses[ConstantNum]; 1370} 1371 1372// getJumpTableEntryAddress - Return the address of the JumpTable with index 1373// 'Index' in the jumpp table that was last initialized with 'initJumpTableInfo' 1374// 1375uintptr_t JITEmitter::getJumpTableEntryAddress(unsigned Index) const { 1376 const std::vector<MachineJumpTableEntry> &JT = JumpTable->getJumpTables(); 1377 assert(Index < JT.size() && "Invalid jump table index!"); 1378 1379 unsigned Offset = 0; 1380 unsigned EntrySize = JumpTable->getEntrySize(); 1381 1382 for (unsigned i = 0; i < Index; ++i) 1383 Offset += JT[i].MBBs.size(); 1384 1385 Offset *= EntrySize; 1386 1387 return (uintptr_t)((char *)JumpTableBase + Offset); 1388} 1389 1390//===----------------------------------------------------------------------===// 1391// Public interface to this file 1392//===----------------------------------------------------------------------===// 1393 1394JITCodeEmitter *JIT::createEmitter(JIT &jit, JITMemoryManager *JMM) { 1395 return new JITEmitter(jit, JMM); 1396} 1397 1398// getPointerToNamedFunction - This function is used as a global wrapper to 1399// JIT::getPointerToNamedFunction for the purpose of resolving symbols when 1400// bugpoint is debugging the JIT. In that scenario, we are loading an .so and 1401// need to resolve function(s) that are being mis-codegenerated, so we need to 1402// resolve their addresses at runtime, and this is the way to do it. 1403extern "C" { 1404 void *getPointerToNamedFunction(const char *Name) { 1405 if (Function *F = TheJIT->FindFunctionNamed(Name)) 1406 return TheJIT->getPointerToFunction(F); 1407 return TheJIT->getPointerToNamedFunction(Name); 1408 } 1409} 1410 1411// getPointerToFunctionOrStub - If the specified function has been 1412// code-gen'd, return a pointer to the function. If not, compile it, or use 1413// a stub to implement lazy compilation if available. 1414// 1415void *JIT::getPointerToFunctionOrStub(Function *F) { 1416 // If we have already code generated the function, just return the address. 1417 if (void *Addr = getPointerToGlobalIfAvailable(F)) 1418 return Addr; 1419 1420 // Get a stub if the target supports it. 1421 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?"); 1422 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter()); 1423 return JE->getJITResolver().getFunctionStub(F); 1424} 1425 1426void JIT::updateFunctionStub(Function *F) { 1427 // Get the empty stub we generated earlier. 1428 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?"); 1429 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter()); 1430 void *Stub = JE->getJITResolver().getFunctionStub(F); 1431 1432 // Tell the target jit info to rewrite the stub at the specified address, 1433 // rather than creating a new one. 1434 void *Addr = getPointerToGlobalIfAvailable(F); 1435 getJITInfo().emitFunctionStubAtAddr(F, Addr, Stub, *getCodeEmitter()); 1436} 1437 1438/// updateDlsymStubTable - Emit the data necessary to relocate the stubs 1439/// that were emitted during code generation. 1440/// 1441void JIT::updateDlsymStubTable() { 1442 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?"); 1443 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter()); 1444 1445 SmallVector<GlobalValue*, 8> GVs; 1446 SmallVector<void*, 8> Ptrs; 1447 const StringMap<void *> &ExtFns = JE->getExternalFnStubs(); 1448 1449 JE->getJITResolver().getRelocatableGVs(GVs, Ptrs); 1450 1451 unsigned nStubs = GVs.size() + ExtFns.size(); 1452 1453 // If there are no relocatable stubs, return. 1454 if (nStubs == 0) 1455 return; 1456 1457 // If there are no new relocatable stubs, return. 1458 void *CurTable = JE->getMemMgr()->getDlsymTable(); 1459 if (CurTable && (*(unsigned *)CurTable == nStubs)) 1460 return; 1461 1462 // Calculate the size of the stub info 1463 unsigned offset = 4 + 4 * nStubs + sizeof(intptr_t) * nStubs; 1464 1465 SmallVector<unsigned, 8> Offsets; 1466 for (unsigned i = 0; i != GVs.size(); ++i) { 1467 Offsets.push_back(offset); 1468 offset += GVs[i]->getName().size() + 1; 1469 } 1470 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end(); 1471 i != e; ++i) { 1472 Offsets.push_back(offset); 1473 offset += strlen(i->first()) + 1; 1474 } 1475 1476 // Allocate space for the new "stub", which contains the dlsym table. 1477 JE->startGVStub(0, offset, 4); 1478 1479 // Emit the number of records 1480 JE->emitInt32(nStubs); 1481 1482 // Emit the string offsets 1483 for (unsigned i = 0; i != nStubs; ++i) 1484 JE->emitInt32(Offsets[i]); 1485 1486 // Emit the pointers. Verify that they are at least 2-byte aligned, and set 1487 // the low bit to 0 == GV, 1 == Function, so that the client code doing the 1488 // relocation can write the relocated pointer at the appropriate place in 1489 // the stub. 1490 for (unsigned i = 0; i != GVs.size(); ++i) { 1491 intptr_t Ptr = (intptr_t)Ptrs[i]; 1492 assert((Ptr & 1) == 0 && "Stub pointers must be at least 2-byte aligned!"); 1493 1494 if (isa<Function>(GVs[i])) 1495 Ptr |= (intptr_t)1; 1496 1497 if (sizeof(Ptr) == 8) 1498 JE->emitInt64(Ptr); 1499 else 1500 JE->emitInt32(Ptr); 1501 } 1502 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end(); 1503 i != e; ++i) { 1504 intptr_t Ptr = (intptr_t)i->second | 1; 1505 1506 if (sizeof(Ptr) == 8) 1507 JE->emitInt64(Ptr); 1508 else 1509 JE->emitInt32(Ptr); 1510 } 1511 1512 // Emit the strings. 1513 for (unsigned i = 0; i != GVs.size(); ++i) 1514 JE->emitString(GVs[i]->getName()); 1515 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end(); 1516 i != e; ++i) 1517 JE->emitString(i->first()); 1518 1519 // Tell the JIT memory manager where it is. The JIT Memory Manager will 1520 // deallocate space for the old one, if one existed. 1521 JE->getMemMgr()->SetDlsymTable(JE->finishGVStub(0)); 1522} 1523 1524/// freeMachineCodeForFunction - release machine code memory for given Function. 1525/// 1526void JIT::freeMachineCodeForFunction(Function *F) { 1527 1528 // Delete translation for this from the ExecutionEngine, so it will get 1529 // retranslated next time it is used. 1530 void *OldPtr = updateGlobalMapping(F, 0); 1531 1532 if (OldPtr) 1533 TheJIT->NotifyFreeingMachineCode(*F, OldPtr); 1534 1535 // Free the actual memory for the function body and related stuff. 1536 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?"); 1537 cast<JITEmitter>(JCE)->deallocateMemForFunction(F); 1538} 1539