JITEmitter.cpp revision 7a9034c4db248fe8b8cb82762881b51b221988d3
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 JITResolverState; 67 68 template<typename ValueTy> 69 struct NoRAUWValueMapConfig : public ValueMapConfig<ValueTy> { 70 typedef JITResolverState *ExtraData; 71 static void onRAUW(JITResolverState *, Value *Old, Value *New) { 72 assert(false && "The JIT doesn't know how to handle a" 73 " RAUW on a value it has emitted."); 74 } 75 }; 76 77 struct CallSiteValueMapConfig : public NoRAUWValueMapConfig<Function*> { 78 typedef JITResolverState *ExtraData; 79 static void onDelete(JITResolverState *JRS, Function *F); 80 }; 81 82 class JITResolverState { 83 public: 84 typedef ValueMap<Function*, void*, NoRAUWValueMapConfig<Function*> > 85 FunctionToStubMapTy; 86 typedef std::map<void*, AssertingVH<Function> > CallSiteToFunctionMapTy; 87 typedef ValueMap<Function *, SmallPtrSet<void*, 1>, 88 CallSiteValueMapConfig> FunctionToCallSitesMapTy; 89 typedef std::map<AssertingVH<GlobalValue>, void*> GlobalToIndirectSymMapTy; 90 private: 91 /// FunctionToStubMap - Keep track of the stub created for a particular 92 /// function so that we can reuse them if necessary. 93 FunctionToStubMapTy FunctionToStubMap; 94 95 /// CallSiteToFunctionMap - Keep track of the function that each lazy call 96 /// site corresponds to, and vice versa. 97 CallSiteToFunctionMapTy CallSiteToFunctionMap; 98 FunctionToCallSitesMapTy FunctionToCallSitesMap; 99 100 /// GlobalToIndirectSymMap - Keep track of the indirect symbol created for a 101 /// particular GlobalVariable so that we can reuse them if necessary. 102 GlobalToIndirectSymMapTy GlobalToIndirectSymMap; 103 104 public: 105 JITResolverState() : FunctionToStubMap(this), 106 FunctionToCallSitesMap(this) {} 107 108 FunctionToStubMapTy& getFunctionToStubMap(const MutexGuard& locked) { 109 assert(locked.holds(TheJIT->lock)); 110 return FunctionToStubMap; 111 } 112 113 GlobalToIndirectSymMapTy& getGlobalToIndirectSymMap(const MutexGuard& locked) { 114 assert(locked.holds(TheJIT->lock)); 115 return GlobalToIndirectSymMap; 116 } 117 118 pair<void *, Function *> LookupFunctionFromCallSite( 119 const MutexGuard &locked, void *CallSite) const { 120 assert(locked.holds(TheJIT->lock)); 121 122 // The address given to us for the stub may not be exactly right, it might be 123 // a little bit after the stub. As such, use upper_bound to find it. 124 CallSiteToFunctionMapTy::const_iterator I = 125 CallSiteToFunctionMap.upper_bound(CallSite); 126 assert(I != CallSiteToFunctionMap.begin() && 127 "This is not a known call site!"); 128 --I; 129 return *I; 130 } 131 132 void AddCallSite(const MutexGuard &locked, void *CallSite, Function *F) { 133 assert(locked.holds(TheJIT->lock)); 134 135 bool Inserted = CallSiteToFunctionMap.insert( 136 std::make_pair(CallSite, F)).second; 137 (void)Inserted; 138 assert(Inserted && "Pair was already in CallSiteToFunctionMap"); 139 FunctionToCallSitesMap[F].insert(CallSite); 140 } 141 142 // Returns the Function of the stub if a stub was erased, or NULL if there 143 // was no stub. This function uses the call-site->function map to find a 144 // relevant function, but asserts that only stubs and not other call sites 145 // will be passed in. 146 Function *EraseStub(const MutexGuard &locked, void *Stub) { 147 CallSiteToFunctionMapTy::iterator C2F_I = 148 CallSiteToFunctionMap.find(Stub); 149 if (C2F_I == CallSiteToFunctionMap.end()) { 150 // Not a stub. 151 return NULL; 152 } 153 154 Function *const F = C2F_I->second; 155#ifndef NDEBUG 156 void *RealStub = FunctionToStubMap.lookup(F); 157 assert(RealStub == Stub && 158 "Call-site that wasn't a stub pass in to EraseStub"); 159#endif 160 FunctionToStubMap.erase(F); 161 CallSiteToFunctionMap.erase(C2F_I); 162 163 // Remove the stub from the function->call-sites map, and remove the whole 164 // entry from the map if that was the last call site. 165 FunctionToCallSitesMapTy::iterator F2C_I = FunctionToCallSitesMap.find(F); 166 assert(F2C_I != FunctionToCallSitesMap.end() && 167 "FunctionToCallSitesMap broken"); 168 bool Erased = F2C_I->second.erase(Stub); 169 (void)Erased; 170 assert(Erased && "FunctionToCallSitesMap broken"); 171 if (F2C_I->second.empty()) 172 FunctionToCallSitesMap.erase(F2C_I); 173 174 return F; 175 } 176 177 void EraseAllCallSites(const MutexGuard &locked, Function *F) { 178 assert(locked.holds(TheJIT->lock)); 179 EraseAllCallSitesPrelocked(F); 180 } 181 void EraseAllCallSitesPrelocked(Function *F) { 182 FunctionToCallSitesMapTy::iterator F2C = FunctionToCallSitesMap.find(F); 183 if (F2C == FunctionToCallSitesMap.end()) 184 return; 185 for (SmallPtrSet<void*, 1>::const_iterator I = F2C->second.begin(), 186 E = F2C->second.end(); I != E; ++I) { 187 bool Erased = CallSiteToFunctionMap.erase(*I); 188 (void)Erased; 189 assert(Erased && "Missing call site->function mapping"); 190 } 191 FunctionToCallSitesMap.erase(F2C); 192 } 193 }; 194 195 /// JITResolver - Keep track of, and resolve, call sites for functions that 196 /// have not yet been compiled. 197 class JITResolver { 198 typedef JITResolverState::FunctionToStubMapTy FunctionToStubMapTy; 199 typedef JITResolverState::CallSiteToFunctionMapTy CallSiteToFunctionMapTy; 200 typedef JITResolverState::GlobalToIndirectSymMapTy GlobalToIndirectSymMapTy; 201 202 /// LazyResolverFn - The target lazy resolver function that we actually 203 /// rewrite instructions to use. 204 TargetJITInfo::LazyResolverFn LazyResolverFn; 205 206 JITResolverState state; 207 208 /// ExternalFnToStubMap - This is the equivalent of FunctionToStubMap for 209 /// external functions. 210 std::map<void*, void*> ExternalFnToStubMap; 211 212 /// revGOTMap - map addresses to indexes in the GOT 213 std::map<void*, unsigned> revGOTMap; 214 unsigned nextGOTIndex; 215 216 static JITResolver *TheJITResolver; 217 public: 218 explicit JITResolver(JIT &jit) : nextGOTIndex(0) { 219 TheJIT = &jit; 220 221 LazyResolverFn = jit.getJITInfo().getLazyResolverFunction(JITCompilerFn); 222 assert(TheJITResolver == 0 && "Multiple JIT resolvers?"); 223 TheJITResolver = this; 224 } 225 226 ~JITResolver() { 227 TheJITResolver = 0; 228 } 229 230 /// getFunctionStubIfAvailable - This returns a pointer to a function stub 231 /// if it has already been created. 232 void *getFunctionStubIfAvailable(Function *F); 233 234 /// getFunctionStub - This returns a pointer to a function stub, creating 235 /// one on demand as needed. If empty is true, create a function stub 236 /// pointing at address 0, to be filled in later. 237 void *getFunctionStub(Function *F); 238 239 /// getExternalFunctionStub - Return a stub for the function at the 240 /// specified address, created lazily on demand. 241 void *getExternalFunctionStub(void *FnAddr); 242 243 /// getGlobalValueIndirectSym - Return an indirect symbol containing the 244 /// specified GV address. 245 void *getGlobalValueIndirectSym(GlobalValue *V, void *GVAddress); 246 247 /// AddCallbackAtLocation - If the target is capable of rewriting an 248 /// instruction without the use of a stub, record the location of the use so 249 /// we know which function is being used at the location. 250 void *AddCallbackAtLocation(Function *F, void *Location) { 251 MutexGuard locked(TheJIT->lock); 252 /// Get the target-specific JIT resolver function. 253 state.AddCallSite(locked, Location, F); 254 return (void*)(intptr_t)LazyResolverFn; 255 } 256 257 void getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs, 258 SmallVectorImpl<void*> &Ptrs); 259 260 GlobalValue *invalidateStub(void *Stub); 261 262 /// getGOTIndexForAddress - Return a new or existing index in the GOT for 263 /// an address. This function only manages slots, it does not manage the 264 /// contents of the slots or the memory associated with the GOT. 265 unsigned getGOTIndexForAddr(void *addr); 266 267 /// JITCompilerFn - This function is called to resolve a stub to a compiled 268 /// address. If the LLVM Function corresponding to the stub has not yet 269 /// been compiled, this function compiles it first. 270 static void *JITCompilerFn(void *Stub); 271 }; 272} 273 274JITResolver *JITResolver::TheJITResolver = 0; 275 276void CallSiteValueMapConfig::onDelete(JITResolverState *JRS, Function *F) { 277 JRS->EraseAllCallSitesPrelocked(F); 278} 279 280/// getFunctionStubIfAvailable - This returns a pointer to a function stub 281/// if it has already been created. 282void *JITResolver::getFunctionStubIfAvailable(Function *F) { 283 MutexGuard locked(TheJIT->lock); 284 285 // If we already have a stub for this function, recycle it. 286 return state.getFunctionToStubMap(locked).lookup(F); 287} 288 289/// getFunctionStub - This returns a pointer to a function stub, creating 290/// one on demand as needed. 291void *JITResolver::getFunctionStub(Function *F) { 292 MutexGuard locked(TheJIT->lock); 293 294 // If we already have a stub for this function, recycle it. 295 void *&Stub = state.getFunctionToStubMap(locked)[F]; 296 if (Stub) return Stub; 297 298 // Call the lazy resolver function unless we are JIT'ing non-lazily, in which 299 // case we must resolve the symbol now. 300 void *Actual = TheJIT->isLazyCompilationDisabled() 301 ? (void *)0 : (void *)(intptr_t)LazyResolverFn; 302 303 // If this is an external declaration, attempt to resolve the address now 304 // to place in the stub. 305 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode()) { 306 Actual = TheJIT->getPointerToFunction(F); 307 308 // If we resolved the symbol to a null address (eg. a weak external) 309 // don't emit a stub. Return a null pointer to the application. If dlsym 310 // stubs are enabled, not being able to resolve the address is not 311 // meaningful. 312 if (!Actual && !TheJIT->areDlsymStubsEnabled()) return 0; 313 } 314 315 // Codegen a new stub, calling the lazy resolver or the actual address of the 316 // external function, if it was resolved. 317 Stub = TheJIT->getJITInfo().emitFunctionStub(F, Actual, 318 *TheJIT->getCodeEmitter()); 319 320 if (Actual != (void*)(intptr_t)LazyResolverFn) { 321 // If we are getting the stub for an external function, we really want the 322 // address of the stub in the GlobalAddressMap for the JIT, not the address 323 // of the external function. 324 TheJIT->updateGlobalMapping(F, Stub); 325 } 326 327 DEBUG(errs() << "JIT: Stub emitted at [" << Stub << "] for function '" 328 << F->getName() << "'\n"); 329 330 // Finally, keep track of the stub-to-Function mapping so that the 331 // JITCompilerFn knows which function to compile! 332 state.AddCallSite(locked, Stub, F); 333 334 // If we are JIT'ing non-lazily but need to call a function that does not 335 // exist yet, add it to the JIT's work list so that we can fill in the stub 336 // address later. 337 if (!Actual && TheJIT->isLazyCompilationDisabled()) 338 if (!F->isDeclaration() || F->hasNotBeenReadFromBitcode()) 339 TheJIT->addPendingFunction(F); 340 341 return Stub; 342} 343 344/// getGlobalValueIndirectSym - Return a lazy pointer containing the specified 345/// GV address. 346void *JITResolver::getGlobalValueIndirectSym(GlobalValue *GV, void *GVAddress) { 347 MutexGuard locked(TheJIT->lock); 348 349 // If we already have a stub for this global variable, recycle it. 350 void *&IndirectSym = state.getGlobalToIndirectSymMap(locked)[GV]; 351 if (IndirectSym) return IndirectSym; 352 353 // Otherwise, codegen a new indirect symbol. 354 IndirectSym = TheJIT->getJITInfo().emitGlobalValueIndirectSym(GV, GVAddress, 355 *TheJIT->getCodeEmitter()); 356 357 DEBUG(errs() << "JIT: Indirect symbol emitted at [" << IndirectSym 358 << "] for GV '" << GV->getName() << "'\n"); 359 360 return IndirectSym; 361} 362 363/// getExternalFunctionStub - Return a stub for the function at the 364/// specified address, created lazily on demand. 365void *JITResolver::getExternalFunctionStub(void *FnAddr) { 366 // If we already have a stub for this function, recycle it. 367 void *&Stub = ExternalFnToStubMap[FnAddr]; 368 if (Stub) return Stub; 369 370 Stub = TheJIT->getJITInfo().emitFunctionStub(0, FnAddr, 371 *TheJIT->getCodeEmitter()); 372 373 DEBUG(errs() << "JIT: Stub emitted at [" << Stub 374 << "] for external function at '" << FnAddr << "'\n"); 375 return Stub; 376} 377 378unsigned JITResolver::getGOTIndexForAddr(void* addr) { 379 unsigned idx = revGOTMap[addr]; 380 if (!idx) { 381 idx = ++nextGOTIndex; 382 revGOTMap[addr] = idx; 383 DEBUG(errs() << "JIT: Adding GOT entry " << idx << " for addr [" 384 << addr << "]\n"); 385 } 386 return idx; 387} 388 389void JITResolver::getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs, 390 SmallVectorImpl<void*> &Ptrs) { 391 MutexGuard locked(TheJIT->lock); 392 393 const FunctionToStubMapTy &FM = state.getFunctionToStubMap(locked); 394 GlobalToIndirectSymMapTy &GM = state.getGlobalToIndirectSymMap(locked); 395 396 for (FunctionToStubMapTy::const_iterator i = FM.begin(), e = FM.end(); 397 i != e; ++i){ 398 Function *F = i->first; 399 if (F->isDeclaration() && F->hasExternalLinkage()) { 400 GVs.push_back(i->first); 401 Ptrs.push_back(i->second); 402 } 403 } 404 for (GlobalToIndirectSymMapTy::iterator i = GM.begin(), e = GM.end(); 405 i != e; ++i) { 406 GVs.push_back(i->first); 407 Ptrs.push_back(i->second); 408 } 409} 410 411GlobalValue *JITResolver::invalidateStub(void *Stub) { 412 MutexGuard locked(TheJIT->lock); 413 414 GlobalToIndirectSymMapTy &GM = state.getGlobalToIndirectSymMap(locked); 415 416 // Look up the cheap way first, to see if it's a function stub we are 417 // invalidating. If so, remove it from both the forward and reverse maps. 418 if (Function *F = state.EraseStub(locked, Stub)) { 419 return F; 420 } 421 422 // Otherwise, it might be an indirect symbol stub. Find it and remove it. 423 for (GlobalToIndirectSymMapTy::iterator i = GM.begin(), e = GM.end(); 424 i != e; ++i) { 425 if (i->second != Stub) 426 continue; 427 GlobalValue *GV = i->first; 428 GM.erase(i); 429 return GV; 430 } 431 432 // Lastly, check to see if it's in the ExternalFnToStubMap. 433 for (std::map<void *, void *>::iterator i = ExternalFnToStubMap.begin(), 434 e = ExternalFnToStubMap.end(); i != e; ++i) { 435 if (i->second != Stub) 436 continue; 437 ExternalFnToStubMap.erase(i); 438 break; 439 } 440 441 return 0; 442} 443 444/// JITCompilerFn - This function is called when a lazy compilation stub has 445/// been entered. It looks up which function this stub corresponds to, compiles 446/// it if necessary, then returns the resultant function pointer. 447void *JITResolver::JITCompilerFn(void *Stub) { 448 JITResolver &JR = *TheJITResolver; 449 450 Function* F = 0; 451 void* ActualPtr = 0; 452 453 { 454 // Only lock for getting the Function. The call getPointerToFunction made 455 // in this function might trigger function materializing, which requires 456 // JIT lock to be unlocked. 457 MutexGuard locked(TheJIT->lock); 458 459 // The address given to us for the stub may not be exactly right, it might 460 // be a little bit after the stub. As such, use upper_bound to find it. 461 pair<void*, Function*> I = 462 JR.state.LookupFunctionFromCallSite(locked, Stub); 463 F = I.second; 464 ActualPtr = I.first; 465 } 466 467 // If we have already code generated the function, just return the address. 468 void *Result = TheJIT->getPointerToGlobalIfAvailable(F); 469 470 if (!Result) { 471 // Otherwise we don't have it, do lazy compilation now. 472 473 // If lazy compilation is disabled, emit a useful error message and abort. 474 if (TheJIT->isLazyCompilationDisabled()) { 475 llvm_report_error("LLVM JIT requested to do lazy compilation of function '" 476 + F->getName() + "' when lazy compiles are disabled!"); 477 } 478 479 DEBUG(errs() << "JIT: Lazily resolving function '" << F->getName() 480 << "' In stub ptr = " << Stub << " actual ptr = " 481 << ActualPtr << "\n"); 482 483 Result = TheJIT->getPointerToFunction(F); 484 } 485 486 // Reacquire the lock to update the GOT map. 487 MutexGuard locked(TheJIT->lock); 488 489 // We might like to remove the call site from the CallSiteToFunction map, but 490 // we can't do that! Multiple threads could be stuck, waiting to acquire the 491 // lock above. As soon as the 1st function finishes compiling the function, 492 // the next one will be released, and needs to be able to find the function it 493 // needs to call. 494 495 // FIXME: We could rewrite all references to this stub if we knew them. 496 497 // What we will do is set the compiled function address to map to the 498 // same GOT entry as the stub so that later clients may update the GOT 499 // if they see it still using the stub address. 500 // Note: this is done so the Resolver doesn't have to manage GOT memory 501 // Do this without allocating map space if the target isn't using a GOT 502 if(JR.revGOTMap.find(Stub) != JR.revGOTMap.end()) 503 JR.revGOTMap[Result] = JR.revGOTMap[Stub]; 504 505 return Result; 506} 507 508//===----------------------------------------------------------------------===// 509// JITEmitter code. 510// 511namespace { 512 /// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is 513 /// used to output functions to memory for execution. 514 class JITEmitter : public JITCodeEmitter { 515 JITMemoryManager *MemMgr; 516 517 // When outputting a function stub in the context of some other function, we 518 // save BufferBegin/BufferEnd/CurBufferPtr here. 519 uint8_t *SavedBufferBegin, *SavedBufferEnd, *SavedCurBufferPtr; 520 521 // When reattempting to JIT a function after running out of space, we store 522 // the estimated size of the function we're trying to JIT here, so we can 523 // ask the memory manager for at least this much space. When we 524 // successfully emit the function, we reset this back to zero. 525 uintptr_t SizeEstimate; 526 527 /// Relocations - These are the relocations that the function needs, as 528 /// emitted. 529 std::vector<MachineRelocation> Relocations; 530 531 /// MBBLocations - This vector is a mapping from MBB ID's to their address. 532 /// It is filled in by the StartMachineBasicBlock callback and queried by 533 /// the getMachineBasicBlockAddress callback. 534 std::vector<uintptr_t> MBBLocations; 535 536 /// ConstantPool - The constant pool for the current function. 537 /// 538 MachineConstantPool *ConstantPool; 539 540 /// ConstantPoolBase - A pointer to the first entry in the constant pool. 541 /// 542 void *ConstantPoolBase; 543 544 /// ConstPoolAddresses - Addresses of individual constant pool entries. 545 /// 546 SmallVector<uintptr_t, 8> ConstPoolAddresses; 547 548 /// JumpTable - The jump tables for the current function. 549 /// 550 MachineJumpTableInfo *JumpTable; 551 552 /// JumpTableBase - A pointer to the first entry in the jump table. 553 /// 554 void *JumpTableBase; 555 556 /// Resolver - This contains info about the currently resolved functions. 557 JITResolver Resolver; 558 559 /// DE - The dwarf emitter for the jit. 560 OwningPtr<JITDwarfEmitter> DE; 561 562 /// DR - The debug registerer for the jit. 563 OwningPtr<JITDebugRegisterer> DR; 564 565 /// LabelLocations - This vector is a mapping from Label ID's to their 566 /// address. 567 std::vector<uintptr_t> LabelLocations; 568 569 /// MMI - Machine module info for exception informations 570 MachineModuleInfo* MMI; 571 572 // GVSet - a set to keep track of which globals have been seen 573 SmallPtrSet<const GlobalVariable*, 8> GVSet; 574 575 // CurFn - The llvm function being emitted. Only valid during 576 // finishFunction(). 577 const Function *CurFn; 578 579 /// Information about emitted code, which is passed to the 580 /// JITEventListeners. This is reset in startFunction and used in 581 /// finishFunction. 582 JITEvent_EmittedFunctionDetails EmissionDetails; 583 584 struct EmittedCode { 585 void *FunctionBody; // Beginning of the function's allocation. 586 void *Code; // The address the function's code actually starts at. 587 void *ExceptionTable; 588 EmittedCode() : FunctionBody(0), Code(0), ExceptionTable(0) {} 589 }; 590 struct EmittedFunctionConfig : public ValueMapConfig<const Function*> { 591 typedef JITEmitter *ExtraData; 592 static void onDelete(JITEmitter *, const Function*); 593 static void onRAUW(JITEmitter *, const Function*, const Function*); 594 }; 595 ValueMap<const Function *, EmittedCode, 596 EmittedFunctionConfig> EmittedFunctions; 597 598 // CurFnStubUses - For a given Function, a vector of stubs that it 599 // references. This facilitates the JIT detecting that a stub is no 600 // longer used, so that it may be deallocated. 601 DenseMap<AssertingVH<const Function>, SmallVector<void*, 1> > CurFnStubUses; 602 603 // StubFnRefs - For a given pointer to a stub, a set of Functions which 604 // reference the stub. When the count of a stub's references drops to zero, 605 // the stub is unused. 606 DenseMap<void *, SmallPtrSet<const Function*, 1> > StubFnRefs; 607 608 // ExtFnStubs - A map of external function names to stubs which have entries 609 // in the JITResolver's ExternalFnToStubMap. 610 StringMap<void *> ExtFnStubs; 611 612 DebugLocTuple PrevDLT; 613 614 public: 615 JITEmitter(JIT &jit, JITMemoryManager *JMM, TargetMachine &TM) 616 : SizeEstimate(0), Resolver(jit), MMI(0), CurFn(0), 617 EmittedFunctions(this) { 618 MemMgr = JMM ? JMM : JITMemoryManager::CreateDefaultMemManager(); 619 if (jit.getJITInfo().needsGOT()) { 620 MemMgr->AllocateGOT(); 621 DEBUG(errs() << "JIT is managing a GOT\n"); 622 } 623 624 if (DwarfExceptionHandling || JITEmitDebugInfo) { 625 DE.reset(new JITDwarfEmitter(jit)); 626 } 627 if (JITEmitDebugInfo) { 628 DR.reset(new JITDebugRegisterer(TM)); 629 } 630 } 631 ~JITEmitter() { 632 delete MemMgr; 633 } 634 635 /// classof - Methods for support type inquiry through isa, cast, and 636 /// dyn_cast: 637 /// 638 static inline bool classof(const JITEmitter*) { return true; } 639 static inline bool classof(const MachineCodeEmitter*) { return true; } 640 641 JITResolver &getJITResolver() { return Resolver; } 642 643 virtual void startFunction(MachineFunction &F); 644 virtual bool finishFunction(MachineFunction &F); 645 646 void emitConstantPool(MachineConstantPool *MCP); 647 void initJumpTableInfo(MachineJumpTableInfo *MJTI); 648 void emitJumpTableInfo(MachineJumpTableInfo *MJTI); 649 650 virtual void startGVStub(const GlobalValue* GV, unsigned StubSize, 651 unsigned Alignment = 1); 652 virtual void startGVStub(const GlobalValue* GV, void *Buffer, 653 unsigned StubSize); 654 virtual void* finishGVStub(const GlobalValue *GV); 655 656 /// allocateSpace - Reserves space in the current block if any, or 657 /// allocate a new one of the given size. 658 virtual void *allocateSpace(uintptr_t Size, unsigned Alignment); 659 660 /// allocateGlobal - Allocate memory for a global. Unlike allocateSpace, 661 /// this method does not allocate memory in the current output buffer, 662 /// because a global may live longer than the current function. 663 virtual void *allocateGlobal(uintptr_t Size, unsigned Alignment); 664 665 virtual void addRelocation(const MachineRelocation &MR) { 666 Relocations.push_back(MR); 667 } 668 669 virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) { 670 if (MBBLocations.size() <= (unsigned)MBB->getNumber()) 671 MBBLocations.resize((MBB->getNumber()+1)*2); 672 MBBLocations[MBB->getNumber()] = getCurrentPCValue(); 673 DEBUG(errs() << "JIT: Emitting BB" << MBB->getNumber() << " at [" 674 << (void*) getCurrentPCValue() << "]\n"); 675 } 676 677 virtual uintptr_t getConstantPoolEntryAddress(unsigned Entry) const; 678 virtual uintptr_t getJumpTableEntryAddress(unsigned Entry) const; 679 680 virtual uintptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const { 681 assert(MBBLocations.size() > (unsigned)MBB->getNumber() && 682 MBBLocations[MBB->getNumber()] && "MBB not emitted!"); 683 return MBBLocations[MBB->getNumber()]; 684 } 685 686 /// retryWithMoreMemory - Log a retry and deallocate all memory for the 687 /// given function. Increase the minimum allocation size so that we get 688 /// more memory next time. 689 void retryWithMoreMemory(MachineFunction &F); 690 691 /// deallocateMemForFunction - Deallocate all memory for the specified 692 /// function body. 693 void deallocateMemForFunction(const Function *F); 694 695 /// AddStubToCurrentFunction - Mark the current function being JIT'd as 696 /// using the stub at the specified address. Allows 697 /// deallocateMemForFunction to also remove stubs no longer referenced. 698 void AddStubToCurrentFunction(void *Stub); 699 700 /// getExternalFnStubs - Accessor for the JIT to find stubs emitted for 701 /// MachineRelocations that reference external functions by name. 702 const StringMap<void*> &getExternalFnStubs() const { return ExtFnStubs; } 703 704 virtual void processDebugLoc(DebugLoc DL, bool BeforePrintingInsn); 705 706 virtual void emitLabel(uint64_t LabelID) { 707 if (LabelLocations.size() <= LabelID) 708 LabelLocations.resize((LabelID+1)*2); 709 LabelLocations[LabelID] = getCurrentPCValue(); 710 } 711 712 virtual uintptr_t getLabelAddress(uint64_t LabelID) const { 713 assert(LabelLocations.size() > (unsigned)LabelID && 714 LabelLocations[LabelID] && "Label not emitted!"); 715 return LabelLocations[LabelID]; 716 } 717 718 virtual void setModuleInfo(MachineModuleInfo* Info) { 719 MMI = Info; 720 if (DE.get()) DE->setModuleInfo(Info); 721 } 722 723 void setMemoryExecutable() { 724 MemMgr->setMemoryExecutable(); 725 } 726 727 JITMemoryManager *getMemMgr() const { return MemMgr; } 728 729 private: 730 void *getPointerToGlobal(GlobalValue *GV, void *Reference, bool NoNeedStub); 731 void *getPointerToGVIndirectSym(GlobalValue *V, void *Reference, 732 bool NoNeedStub); 733 unsigned addSizeOfGlobal(const GlobalVariable *GV, unsigned Size); 734 unsigned addSizeOfGlobalsInConstantVal(const Constant *C, unsigned Size); 735 unsigned addSizeOfGlobalsInInitializer(const Constant *Init, unsigned Size); 736 unsigned GetSizeOfGlobalsInBytes(MachineFunction &MF); 737 }; 738} 739 740void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference, 741 bool DoesntNeedStub) { 742 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) 743 return TheJIT->getOrEmitGlobalVariable(GV); 744 745 if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) 746 return TheJIT->getPointerToGlobal(GA->resolveAliasedGlobal(false)); 747 748 // If we have already compiled the function, return a pointer to its body. 749 Function *F = cast<Function>(V); 750 void *ResultPtr; 751 if (!DoesntNeedStub) { 752 // Return the function stub if it's already created. 753 ResultPtr = Resolver.getFunctionStubIfAvailable(F); 754 if (ResultPtr) 755 AddStubToCurrentFunction(ResultPtr); 756 } else { 757 ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F); 758 } 759 if (ResultPtr) return ResultPtr; 760 761 // If this is an external function pointer, we can force the JIT to 762 // 'compile' it, which really just adds it to the map. In dlsym mode, 763 // external functions are forced through a stub, regardless of reloc type. 764 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode() && 765 DoesntNeedStub && !TheJIT->areDlsymStubsEnabled()) 766 return TheJIT->getPointerToFunction(F); 767 768 // Okay, the function has not been compiled yet, if the target callback 769 // mechanism is capable of rewriting the instruction directly, prefer to do 770 // that instead of emitting a stub. This uses the lazy resolver, so is not 771 // legal if lazy compilation is disabled. 772 if (DoesntNeedStub && !TheJIT->isLazyCompilationDisabled()) 773 return Resolver.AddCallbackAtLocation(F, Reference); 774 775 // Otherwise, we have to emit a stub. 776 void *StubAddr = Resolver.getFunctionStub(F); 777 778 // Add the stub to the current function's list of referenced stubs, so we can 779 // deallocate them if the current function is ever freed. It's possible to 780 // return null from getFunctionStub in the case of a weak extern that fails 781 // to resolve. 782 if (StubAddr) 783 AddStubToCurrentFunction(StubAddr); 784 785 return StubAddr; 786} 787 788void *JITEmitter::getPointerToGVIndirectSym(GlobalValue *V, void *Reference, 789 bool NoNeedStub) { 790 // Make sure GV is emitted first, and create a stub containing the fully 791 // resolved address. 792 void *GVAddress = getPointerToGlobal(V, Reference, true); 793 void *StubAddr = Resolver.getGlobalValueIndirectSym(V, GVAddress); 794 795 // Add the stub to the current function's list of referenced stubs, so we can 796 // deallocate them if the current function is ever freed. 797 AddStubToCurrentFunction(StubAddr); 798 799 return StubAddr; 800} 801 802void JITEmitter::AddStubToCurrentFunction(void *StubAddr) { 803 assert(CurFn && "Stub added to current function, but current function is 0!"); 804 805 SmallVectorImpl<void*> &StubsUsed = CurFnStubUses[CurFn]; 806 StubsUsed.push_back(StubAddr); 807 808 SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[StubAddr]; 809 FnRefs.insert(CurFn); 810} 811 812void JITEmitter::processDebugLoc(DebugLoc DL, bool BeforePrintingInsn) { 813 if (!DL.isUnknown()) { 814 DebugLocTuple CurDLT = EmissionDetails.MF->getDebugLocTuple(DL); 815 816 if (BeforePrintingInsn) { 817 if (CurDLT.Scope != 0 && PrevDLT != CurDLT) { 818 JITEvent_EmittedFunctionDetails::LineStart NextLine; 819 NextLine.Address = getCurrentPCValue(); 820 NextLine.Loc = DL; 821 EmissionDetails.LineStarts.push_back(NextLine); 822 } 823 824 PrevDLT = CurDLT; 825 } 826 } 827} 828 829static unsigned GetConstantPoolSizeInBytes(MachineConstantPool *MCP, 830 const TargetData *TD) { 831 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants(); 832 if (Constants.empty()) return 0; 833 834 unsigned Size = 0; 835 for (unsigned i = 0, e = Constants.size(); i != e; ++i) { 836 MachineConstantPoolEntry CPE = Constants[i]; 837 unsigned AlignMask = CPE.getAlignment() - 1; 838 Size = (Size + AlignMask) & ~AlignMask; 839 const Type *Ty = CPE.getType(); 840 Size += TD->getTypeAllocSize(Ty); 841 } 842 return Size; 843} 844 845static unsigned GetJumpTableSizeInBytes(MachineJumpTableInfo *MJTI) { 846 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables(); 847 if (JT.empty()) return 0; 848 849 unsigned NumEntries = 0; 850 for (unsigned i = 0, e = JT.size(); i != e; ++i) 851 NumEntries += JT[i].MBBs.size(); 852 853 unsigned EntrySize = MJTI->getEntrySize(); 854 855 return NumEntries * EntrySize; 856} 857 858static uintptr_t RoundUpToAlign(uintptr_t Size, unsigned Alignment) { 859 if (Alignment == 0) Alignment = 1; 860 // Since we do not know where the buffer will be allocated, be pessimistic. 861 return Size + Alignment; 862} 863 864/// addSizeOfGlobal - add the size of the global (plus any alignment padding) 865/// into the running total Size. 866 867unsigned JITEmitter::addSizeOfGlobal(const GlobalVariable *GV, unsigned Size) { 868 const Type *ElTy = GV->getType()->getElementType(); 869 size_t GVSize = (size_t)TheJIT->getTargetData()->getTypeAllocSize(ElTy); 870 size_t GVAlign = 871 (size_t)TheJIT->getTargetData()->getPreferredAlignment(GV); 872 DEBUG(errs() << "JIT: Adding in size " << GVSize << " alignment " << GVAlign); 873 DEBUG(GV->dump()); 874 // Assume code section ends with worst possible alignment, so first 875 // variable needs maximal padding. 876 if (Size==0) 877 Size = 1; 878 Size = ((Size+GVAlign-1)/GVAlign)*GVAlign; 879 Size += GVSize; 880 return Size; 881} 882 883/// addSizeOfGlobalsInConstantVal - find any globals that we haven't seen yet 884/// but are referenced from the constant; put them in GVSet and add their 885/// size into the running total Size. 886 887unsigned JITEmitter::addSizeOfGlobalsInConstantVal(const Constant *C, 888 unsigned Size) { 889 // If its undefined, return the garbage. 890 if (isa<UndefValue>(C)) 891 return Size; 892 893 // If the value is a ConstantExpr 894 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) { 895 Constant *Op0 = CE->getOperand(0); 896 switch (CE->getOpcode()) { 897 case Instruction::GetElementPtr: 898 case Instruction::Trunc: 899 case Instruction::ZExt: 900 case Instruction::SExt: 901 case Instruction::FPTrunc: 902 case Instruction::FPExt: 903 case Instruction::UIToFP: 904 case Instruction::SIToFP: 905 case Instruction::FPToUI: 906 case Instruction::FPToSI: 907 case Instruction::PtrToInt: 908 case Instruction::IntToPtr: 909 case Instruction::BitCast: { 910 Size = addSizeOfGlobalsInConstantVal(Op0, Size); 911 break; 912 } 913 case Instruction::Add: 914 case Instruction::FAdd: 915 case Instruction::Sub: 916 case Instruction::FSub: 917 case Instruction::Mul: 918 case Instruction::FMul: 919 case Instruction::UDiv: 920 case Instruction::SDiv: 921 case Instruction::URem: 922 case Instruction::SRem: 923 case Instruction::And: 924 case Instruction::Or: 925 case Instruction::Xor: { 926 Size = addSizeOfGlobalsInConstantVal(Op0, Size); 927 Size = addSizeOfGlobalsInConstantVal(CE->getOperand(1), Size); 928 break; 929 } 930 default: { 931 std::string msg; 932 raw_string_ostream Msg(msg); 933 Msg << "ConstantExpr not handled: " << *CE; 934 llvm_report_error(Msg.str()); 935 } 936 } 937 } 938 939 if (C->getType()->getTypeID() == Type::PointerTyID) 940 if (const GlobalVariable* GV = dyn_cast<GlobalVariable>(C)) 941 if (GVSet.insert(GV)) 942 Size = addSizeOfGlobal(GV, Size); 943 944 return Size; 945} 946 947/// addSizeOfGLobalsInInitializer - handle any globals that we haven't seen yet 948/// but are referenced from the given initializer. 949 950unsigned JITEmitter::addSizeOfGlobalsInInitializer(const Constant *Init, 951 unsigned Size) { 952 if (!isa<UndefValue>(Init) && 953 !isa<ConstantVector>(Init) && 954 !isa<ConstantAggregateZero>(Init) && 955 !isa<ConstantArray>(Init) && 956 !isa<ConstantStruct>(Init) && 957 Init->getType()->isFirstClassType()) 958 Size = addSizeOfGlobalsInConstantVal(Init, Size); 959 return Size; 960} 961 962/// GetSizeOfGlobalsInBytes - walk the code for the function, looking for 963/// globals; then walk the initializers of those globals looking for more. 964/// If their size has not been considered yet, add it into the running total 965/// Size. 966 967unsigned JITEmitter::GetSizeOfGlobalsInBytes(MachineFunction &MF) { 968 unsigned Size = 0; 969 GVSet.clear(); 970 971 for (MachineFunction::iterator MBB = MF.begin(), E = MF.end(); 972 MBB != E; ++MBB) { 973 for (MachineBasicBlock::const_iterator I = MBB->begin(), E = MBB->end(); 974 I != E; ++I) { 975 const TargetInstrDesc &Desc = I->getDesc(); 976 const MachineInstr &MI = *I; 977 unsigned NumOps = Desc.getNumOperands(); 978 for (unsigned CurOp = 0; CurOp < NumOps; CurOp++) { 979 const MachineOperand &MO = MI.getOperand(CurOp); 980 if (MO.isGlobal()) { 981 GlobalValue* V = MO.getGlobal(); 982 const GlobalVariable *GV = dyn_cast<const GlobalVariable>(V); 983 if (!GV) 984 continue; 985 // If seen in previous function, it will have an entry here. 986 if (TheJIT->getPointerToGlobalIfAvailable(GV)) 987 continue; 988 // If seen earlier in this function, it will have an entry here. 989 // FIXME: it should be possible to combine these tables, by 990 // assuming the addresses of the new globals in this module 991 // start at 0 (or something) and adjusting them after codegen 992 // complete. Another possibility is to grab a marker bit in GV. 993 if (GVSet.insert(GV)) 994 // A variable as yet unseen. Add in its size. 995 Size = addSizeOfGlobal(GV, Size); 996 } 997 } 998 } 999 } 1000 DEBUG(errs() << "JIT: About to look through initializers\n"); 1001 // Look for more globals that are referenced only from initializers. 1002 // GVSet.end is computed each time because the set can grow as we go. 1003 for (SmallPtrSet<const GlobalVariable *, 8>::iterator I = GVSet.begin(); 1004 I != GVSet.end(); I++) { 1005 const GlobalVariable* GV = *I; 1006 if (GV->hasInitializer()) 1007 Size = addSizeOfGlobalsInInitializer(GV->getInitializer(), Size); 1008 } 1009 1010 return Size; 1011} 1012 1013void JITEmitter::startFunction(MachineFunction &F) { 1014 DEBUG(errs() << "JIT: Starting CodeGen of Function " 1015 << F.getFunction()->getName() << "\n"); 1016 1017 uintptr_t ActualSize = 0; 1018 // Set the memory writable, if it's not already 1019 MemMgr->setMemoryWritable(); 1020 if (MemMgr->NeedsExactSize()) { 1021 DEBUG(errs() << "JIT: ExactSize\n"); 1022 const TargetInstrInfo* TII = F.getTarget().getInstrInfo(); 1023 MachineJumpTableInfo *MJTI = F.getJumpTableInfo(); 1024 MachineConstantPool *MCP = F.getConstantPool(); 1025 1026 // Ensure the constant pool/jump table info is at least 4-byte aligned. 1027 ActualSize = RoundUpToAlign(ActualSize, 16); 1028 1029 // Add the alignment of the constant pool 1030 ActualSize = RoundUpToAlign(ActualSize, MCP->getConstantPoolAlignment()); 1031 1032 // Add the constant pool size 1033 ActualSize += GetConstantPoolSizeInBytes(MCP, TheJIT->getTargetData()); 1034 1035 // Add the aligment of the jump table info 1036 ActualSize = RoundUpToAlign(ActualSize, MJTI->getAlignment()); 1037 1038 // Add the jump table size 1039 ActualSize += GetJumpTableSizeInBytes(MJTI); 1040 1041 // Add the alignment for the function 1042 ActualSize = RoundUpToAlign(ActualSize, 1043 std::max(F.getFunction()->getAlignment(), 8U)); 1044 1045 // Add the function size 1046 ActualSize += TII->GetFunctionSizeInBytes(F); 1047 1048 DEBUG(errs() << "JIT: ActualSize before globals " << ActualSize << "\n"); 1049 // Add the size of the globals that will be allocated after this function. 1050 // These are all the ones referenced from this function that were not 1051 // previously allocated. 1052 ActualSize += GetSizeOfGlobalsInBytes(F); 1053 DEBUG(errs() << "JIT: ActualSize after globals " << ActualSize << "\n"); 1054 } else if (SizeEstimate > 0) { 1055 // SizeEstimate will be non-zero on reallocation attempts. 1056 ActualSize = SizeEstimate; 1057 } 1058 1059 BufferBegin = CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(), 1060 ActualSize); 1061 BufferEnd = BufferBegin+ActualSize; 1062 EmittedFunctions[F.getFunction()].FunctionBody = BufferBegin; 1063 1064 // Ensure the constant pool/jump table info is at least 4-byte aligned. 1065 emitAlignment(16); 1066 1067 emitConstantPool(F.getConstantPool()); 1068 initJumpTableInfo(F.getJumpTableInfo()); 1069 1070 // About to start emitting the machine code for the function. 1071 emitAlignment(std::max(F.getFunction()->getAlignment(), 8U)); 1072 TheJIT->updateGlobalMapping(F.getFunction(), CurBufferPtr); 1073 EmittedFunctions[F.getFunction()].Code = CurBufferPtr; 1074 1075 MBBLocations.clear(); 1076 1077 EmissionDetails.MF = &F; 1078 EmissionDetails.LineStarts.clear(); 1079} 1080 1081bool JITEmitter::finishFunction(MachineFunction &F) { 1082 if (CurBufferPtr == BufferEnd) { 1083 // We must call endFunctionBody before retrying, because 1084 // deallocateMemForFunction requires it. 1085 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, CurBufferPtr); 1086 retryWithMoreMemory(F); 1087 return true; 1088 } 1089 1090 emitJumpTableInfo(F.getJumpTableInfo()); 1091 1092 // FnStart is the start of the text, not the start of the constant pool and 1093 // other per-function data. 1094 uint8_t *FnStart = 1095 (uint8_t *)TheJIT->getPointerToGlobalIfAvailable(F.getFunction()); 1096 1097 // FnEnd is the end of the function's machine code. 1098 uint8_t *FnEnd = CurBufferPtr; 1099 1100 if (!Relocations.empty()) { 1101 CurFn = F.getFunction(); 1102 NumRelos += Relocations.size(); 1103 1104 // Resolve the relocations to concrete pointers. 1105 for (unsigned i = 0, e = Relocations.size(); i != e; ++i) { 1106 MachineRelocation &MR = Relocations[i]; 1107 void *ResultPtr = 0; 1108 if (!MR.letTargetResolve()) { 1109 if (MR.isExternalSymbol()) { 1110 ResultPtr = TheJIT->getPointerToNamedFunction(MR.getExternalSymbol(), 1111 false); 1112 DEBUG(errs() << "JIT: Map \'" << MR.getExternalSymbol() << "\' to [" 1113 << ResultPtr << "]\n"); 1114 1115 // If the target REALLY wants a stub for this function, emit it now. 1116 if (!MR.doesntNeedStub()) { 1117 if (!TheJIT->areDlsymStubsEnabled()) { 1118 ResultPtr = Resolver.getExternalFunctionStub(ResultPtr); 1119 } else { 1120 void *&Stub = ExtFnStubs[MR.getExternalSymbol()]; 1121 if (!Stub) { 1122 Stub = Resolver.getExternalFunctionStub((void *)&Stub); 1123 AddStubToCurrentFunction(Stub); 1124 } 1125 ResultPtr = Stub; 1126 } 1127 } 1128 } else if (MR.isGlobalValue()) { 1129 ResultPtr = getPointerToGlobal(MR.getGlobalValue(), 1130 BufferBegin+MR.getMachineCodeOffset(), 1131 MR.doesntNeedStub()); 1132 } else if (MR.isIndirectSymbol()) { 1133 ResultPtr = getPointerToGVIndirectSym(MR.getGlobalValue(), 1134 BufferBegin+MR.getMachineCodeOffset(), 1135 MR.doesntNeedStub()); 1136 } else if (MR.isBasicBlock()) { 1137 ResultPtr = (void*)getMachineBasicBlockAddress(MR.getBasicBlock()); 1138 } else if (MR.isConstantPoolIndex()) { 1139 ResultPtr = (void*)getConstantPoolEntryAddress(MR.getConstantPoolIndex()); 1140 } else { 1141 assert(MR.isJumpTableIndex()); 1142 ResultPtr=(void*)getJumpTableEntryAddress(MR.getJumpTableIndex()); 1143 } 1144 1145 MR.setResultPointer(ResultPtr); 1146 } 1147 1148 // if we are managing the GOT and the relocation wants an index, 1149 // give it one 1150 if (MR.isGOTRelative() && MemMgr->isManagingGOT()) { 1151 unsigned idx = Resolver.getGOTIndexForAddr(ResultPtr); 1152 MR.setGOTIndex(idx); 1153 if (((void**)MemMgr->getGOTBase())[idx] != ResultPtr) { 1154 DEBUG(errs() << "JIT: GOT was out of date for " << ResultPtr 1155 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx] 1156 << "\n"); 1157 ((void**)MemMgr->getGOTBase())[idx] = ResultPtr; 1158 } 1159 } 1160 } 1161 1162 CurFn = 0; 1163 TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0], 1164 Relocations.size(), MemMgr->getGOTBase()); 1165 } 1166 1167 // Update the GOT entry for F to point to the new code. 1168 if (MemMgr->isManagingGOT()) { 1169 unsigned idx = Resolver.getGOTIndexForAddr((void*)BufferBegin); 1170 if (((void**)MemMgr->getGOTBase())[idx] != (void*)BufferBegin) { 1171 DEBUG(errs() << "JIT: GOT was out of date for " << (void*)BufferBegin 1172 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx] 1173 << "\n"); 1174 ((void**)MemMgr->getGOTBase())[idx] = (void*)BufferBegin; 1175 } 1176 } 1177 1178 // CurBufferPtr may have moved beyond FnEnd, due to memory allocation for 1179 // global variables that were referenced in the relocations. 1180 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, CurBufferPtr); 1181 1182 if (CurBufferPtr == BufferEnd) { 1183 retryWithMoreMemory(F); 1184 return true; 1185 } else { 1186 // Now that we've succeeded in emitting the function, reset the 1187 // SizeEstimate back down to zero. 1188 SizeEstimate = 0; 1189 } 1190 1191 BufferBegin = CurBufferPtr = 0; 1192 NumBytes += FnEnd-FnStart; 1193 1194 // Invalidate the icache if necessary. 1195 sys::Memory::InvalidateInstructionCache(FnStart, FnEnd-FnStart); 1196 1197 TheJIT->NotifyFunctionEmitted(*F.getFunction(), FnStart, FnEnd-FnStart, 1198 EmissionDetails); 1199 1200 DEBUG(errs() << "JIT: Finished CodeGen of [" << (void*)FnStart 1201 << "] Function: " << F.getFunction()->getName() 1202 << ": " << (FnEnd-FnStart) << " bytes of text, " 1203 << Relocations.size() << " relocations\n"); 1204 1205 Relocations.clear(); 1206 ConstPoolAddresses.clear(); 1207 1208 // Mark code region readable and executable if it's not so already. 1209 MemMgr->setMemoryExecutable(); 1210 1211 DEBUG( 1212 if (sys::hasDisassembler()) { 1213 errs() << "JIT: Disassembled code:\n"; 1214 errs() << sys::disassembleBuffer(FnStart, FnEnd-FnStart, 1215 (uintptr_t)FnStart); 1216 } else { 1217 errs() << "JIT: Binary code:\n"; 1218 uint8_t* q = FnStart; 1219 for (int i = 0; q < FnEnd; q += 4, ++i) { 1220 if (i == 4) 1221 i = 0; 1222 if (i == 0) 1223 errs() << "JIT: " << (long)(q - FnStart) << ": "; 1224 bool Done = false; 1225 for (int j = 3; j >= 0; --j) { 1226 if (q + j >= FnEnd) 1227 Done = true; 1228 else 1229 errs() << (unsigned short)q[j]; 1230 } 1231 if (Done) 1232 break; 1233 errs() << ' '; 1234 if (i == 3) 1235 errs() << '\n'; 1236 } 1237 errs()<< '\n'; 1238 } 1239 ); 1240 1241 if (DwarfExceptionHandling || JITEmitDebugInfo) { 1242 uintptr_t ActualSize = 0; 1243 SavedBufferBegin = BufferBegin; 1244 SavedBufferEnd = BufferEnd; 1245 SavedCurBufferPtr = CurBufferPtr; 1246 1247 if (MemMgr->NeedsExactSize()) { 1248 ActualSize = DE->GetDwarfTableSizeInBytes(F, *this, FnStart, FnEnd); 1249 } 1250 1251 BufferBegin = CurBufferPtr = MemMgr->startExceptionTable(F.getFunction(), 1252 ActualSize); 1253 BufferEnd = BufferBegin+ActualSize; 1254 EmittedFunctions[F.getFunction()].ExceptionTable = BufferBegin; 1255 uint8_t *EhStart; 1256 uint8_t *FrameRegister = DE->EmitDwarfTable(F, *this, FnStart, FnEnd, 1257 EhStart); 1258 MemMgr->endExceptionTable(F.getFunction(), BufferBegin, CurBufferPtr, 1259 FrameRegister); 1260 uint8_t *EhEnd = CurBufferPtr; 1261 BufferBegin = SavedBufferBegin; 1262 BufferEnd = SavedBufferEnd; 1263 CurBufferPtr = SavedCurBufferPtr; 1264 1265 if (DwarfExceptionHandling) { 1266 TheJIT->RegisterTable(FrameRegister); 1267 } 1268 1269 if (JITEmitDebugInfo) { 1270 DebugInfo I; 1271 I.FnStart = FnStart; 1272 I.FnEnd = FnEnd; 1273 I.EhStart = EhStart; 1274 I.EhEnd = EhEnd; 1275 DR->RegisterFunction(F.getFunction(), I); 1276 } 1277 } 1278 1279 if (MMI) 1280 MMI->EndFunction(); 1281 1282 return false; 1283} 1284 1285void JITEmitter::retryWithMoreMemory(MachineFunction &F) { 1286 DEBUG(errs() << "JIT: Ran out of space for native code. Reattempting.\n"); 1287 Relocations.clear(); // Clear the old relocations or we'll reapply them. 1288 ConstPoolAddresses.clear(); 1289 ++NumRetries; 1290 deallocateMemForFunction(F.getFunction()); 1291 // Try again with at least twice as much free space. 1292 SizeEstimate = (uintptr_t)(2 * (BufferEnd - BufferBegin)); 1293} 1294 1295/// deallocateMemForFunction - Deallocate all memory for the specified 1296/// function body. Also drop any references the function has to stubs. 1297/// May be called while the Function is being destroyed inside ~Value(). 1298void JITEmitter::deallocateMemForFunction(const Function *F) { 1299 ValueMap<const Function *, EmittedCode, EmittedFunctionConfig>::iterator 1300 Emitted = EmittedFunctions.find(F); 1301 if (Emitted != EmittedFunctions.end()) { 1302 MemMgr->deallocateFunctionBody(Emitted->second.FunctionBody); 1303 MemMgr->deallocateExceptionTable(Emitted->second.ExceptionTable); 1304 TheJIT->NotifyFreeingMachineCode(Emitted->second.Code); 1305 1306 EmittedFunctions.erase(Emitted); 1307 } 1308 1309 // TODO: Do we need to unregister exception handling information from libgcc 1310 // here? 1311 1312 if (JITEmitDebugInfo) { 1313 DR->UnregisterFunction(F); 1314 } 1315 1316 // If the function did not reference any stubs, return. 1317 if (CurFnStubUses.find(F) == CurFnStubUses.end()) 1318 return; 1319 1320 // For each referenced stub, erase the reference to this function, and then 1321 // erase the list of referenced stubs. 1322 SmallVectorImpl<void *> &StubList = CurFnStubUses[F]; 1323 for (unsigned i = 0, e = StubList.size(); i != e; ++i) { 1324 void *Stub = StubList[i]; 1325 1326 // If we already invalidated this stub for this function, continue. 1327 if (StubFnRefs.count(Stub) == 0) 1328 continue; 1329 1330 SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[Stub]; 1331 FnRefs.erase(F); 1332 1333 // If this function was the last reference to the stub, invalidate the stub 1334 // in the JITResolver. Were there a memory manager deallocateStub routine, 1335 // we could call that at this point too. 1336 if (FnRefs.empty()) { 1337 DEBUG(errs() << "\nJIT: Invalidated Stub at [" << Stub << "]\n"); 1338 StubFnRefs.erase(Stub); 1339 1340 // Invalidate the stub. If it is a GV stub, update the JIT's global 1341 // mapping for that GV to zero, otherwise, search the string map of 1342 // external function names to stubs and remove the entry for this stub. 1343 GlobalValue *GV = Resolver.invalidateStub(Stub); 1344 if (GV) { 1345 TheJIT->updateGlobalMapping(GV, 0); 1346 } else { 1347 for (StringMapIterator<void*> i = ExtFnStubs.begin(), 1348 e = ExtFnStubs.end(); i != e; ++i) { 1349 if (i->second == Stub) { 1350 ExtFnStubs.erase(i); 1351 break; 1352 } 1353 } 1354 } 1355 } 1356 } 1357 CurFnStubUses.erase(F); 1358} 1359 1360 1361void* JITEmitter::allocateSpace(uintptr_t Size, unsigned Alignment) { 1362 if (BufferBegin) 1363 return JITCodeEmitter::allocateSpace(Size, Alignment); 1364 1365 // create a new memory block if there is no active one. 1366 // care must be taken so that BufferBegin is invalidated when a 1367 // block is trimmed 1368 BufferBegin = CurBufferPtr = MemMgr->allocateSpace(Size, Alignment); 1369 BufferEnd = BufferBegin+Size; 1370 return CurBufferPtr; 1371} 1372 1373void* JITEmitter::allocateGlobal(uintptr_t Size, unsigned Alignment) { 1374 // Delegate this call through the memory manager. 1375 return MemMgr->allocateGlobal(Size, Alignment); 1376} 1377 1378void JITEmitter::emitConstantPool(MachineConstantPool *MCP) { 1379 if (TheJIT->getJITInfo().hasCustomConstantPool()) 1380 return; 1381 1382 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants(); 1383 if (Constants.empty()) return; 1384 1385 unsigned Size = GetConstantPoolSizeInBytes(MCP, TheJIT->getTargetData()); 1386 unsigned Align = MCP->getConstantPoolAlignment(); 1387 ConstantPoolBase = allocateSpace(Size, Align); 1388 ConstantPool = MCP; 1389 1390 if (ConstantPoolBase == 0) return; // Buffer overflow. 1391 1392 DEBUG(errs() << "JIT: Emitted constant pool at [" << ConstantPoolBase 1393 << "] (size: " << Size << ", alignment: " << Align << ")\n"); 1394 1395 // Initialize the memory for all of the constant pool entries. 1396 unsigned Offset = 0; 1397 for (unsigned i = 0, e = Constants.size(); i != e; ++i) { 1398 MachineConstantPoolEntry CPE = Constants[i]; 1399 unsigned AlignMask = CPE.getAlignment() - 1; 1400 Offset = (Offset + AlignMask) & ~AlignMask; 1401 1402 uintptr_t CAddr = (uintptr_t)ConstantPoolBase + Offset; 1403 ConstPoolAddresses.push_back(CAddr); 1404 if (CPE.isMachineConstantPoolEntry()) { 1405 // FIXME: add support to lower machine constant pool values into bytes! 1406 llvm_report_error("Initialize memory with machine specific constant pool" 1407 "entry has not been implemented!"); 1408 } 1409 TheJIT->InitializeMemory(CPE.Val.ConstVal, (void*)CAddr); 1410 DEBUG(errs() << "JIT: CP" << i << " at [0x"; 1411 errs().write_hex(CAddr) << "]\n"); 1412 1413 const Type *Ty = CPE.Val.ConstVal->getType(); 1414 Offset += TheJIT->getTargetData()->getTypeAllocSize(Ty); 1415 } 1416} 1417 1418void JITEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) { 1419 if (TheJIT->getJITInfo().hasCustomJumpTables()) 1420 return; 1421 1422 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables(); 1423 if (JT.empty()) return; 1424 1425 unsigned NumEntries = 0; 1426 for (unsigned i = 0, e = JT.size(); i != e; ++i) 1427 NumEntries += JT[i].MBBs.size(); 1428 1429 unsigned EntrySize = MJTI->getEntrySize(); 1430 1431 // Just allocate space for all the jump tables now. We will fix up the actual 1432 // MBB entries in the tables after we emit the code for each block, since then 1433 // we will know the final locations of the MBBs in memory. 1434 JumpTable = MJTI; 1435 JumpTableBase = allocateSpace(NumEntries * EntrySize, MJTI->getAlignment()); 1436} 1437 1438void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) { 1439 if (TheJIT->getJITInfo().hasCustomJumpTables()) 1440 return; 1441 1442 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables(); 1443 if (JT.empty() || JumpTableBase == 0) return; 1444 1445 if (TargetMachine::getRelocationModel() == Reloc::PIC_) { 1446 assert(MJTI->getEntrySize() == 4 && "Cross JIT'ing?"); 1447 // For each jump table, place the offset from the beginning of the table 1448 // to the target address. 1449 int *SlotPtr = (int*)JumpTableBase; 1450 1451 for (unsigned i = 0, e = JT.size(); i != e; ++i) { 1452 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs; 1453 // Store the offset of the basic block for this jump table slot in the 1454 // memory we allocated for the jump table in 'initJumpTableInfo' 1455 uintptr_t Base = (uintptr_t)SlotPtr; 1456 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) { 1457 uintptr_t MBBAddr = getMachineBasicBlockAddress(MBBs[mi]); 1458 *SlotPtr++ = TheJIT->getJITInfo().getPICJumpTableEntry(MBBAddr, Base); 1459 } 1460 } 1461 } else { 1462 assert(MJTI->getEntrySize() == sizeof(void*) && "Cross JIT'ing?"); 1463 1464 // For each jump table, map each target in the jump table to the address of 1465 // an emitted MachineBasicBlock. 1466 intptr_t *SlotPtr = (intptr_t*)JumpTableBase; 1467 1468 for (unsigned i = 0, e = JT.size(); i != e; ++i) { 1469 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs; 1470 // Store the address of the basic block for this jump table slot in the 1471 // memory we allocated for the jump table in 'initJumpTableInfo' 1472 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) 1473 *SlotPtr++ = getMachineBasicBlockAddress(MBBs[mi]); 1474 } 1475 } 1476} 1477 1478void JITEmitter::startGVStub(const GlobalValue* GV, unsigned StubSize, 1479 unsigned Alignment) { 1480 SavedBufferBegin = BufferBegin; 1481 SavedBufferEnd = BufferEnd; 1482 SavedCurBufferPtr = CurBufferPtr; 1483 1484 BufferBegin = CurBufferPtr = MemMgr->allocateStub(GV, StubSize, Alignment); 1485 BufferEnd = BufferBegin+StubSize+1; 1486} 1487 1488void JITEmitter::startGVStub(const GlobalValue* GV, void *Buffer, 1489 unsigned StubSize) { 1490 SavedBufferBegin = BufferBegin; 1491 SavedBufferEnd = BufferEnd; 1492 SavedCurBufferPtr = CurBufferPtr; 1493 1494 BufferBegin = CurBufferPtr = (uint8_t *)Buffer; 1495 BufferEnd = BufferBegin+StubSize+1; 1496} 1497 1498void *JITEmitter::finishGVStub(const GlobalValue* GV) { 1499 NumBytes += getCurrentPCOffset(); 1500 std::swap(SavedBufferBegin, BufferBegin); 1501 BufferEnd = SavedBufferEnd; 1502 CurBufferPtr = SavedCurBufferPtr; 1503 return SavedBufferBegin; 1504} 1505 1506// getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry 1507// in the constant pool that was last emitted with the 'emitConstantPool' 1508// method. 1509// 1510uintptr_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) const { 1511 assert(ConstantNum < ConstantPool->getConstants().size() && 1512 "Invalid ConstantPoolIndex!"); 1513 return ConstPoolAddresses[ConstantNum]; 1514} 1515 1516// getJumpTableEntryAddress - Return the address of the JumpTable with index 1517// 'Index' in the jumpp table that was last initialized with 'initJumpTableInfo' 1518// 1519uintptr_t JITEmitter::getJumpTableEntryAddress(unsigned Index) const { 1520 const std::vector<MachineJumpTableEntry> &JT = JumpTable->getJumpTables(); 1521 assert(Index < JT.size() && "Invalid jump table index!"); 1522 1523 unsigned Offset = 0; 1524 unsigned EntrySize = JumpTable->getEntrySize(); 1525 1526 for (unsigned i = 0; i < Index; ++i) 1527 Offset += JT[i].MBBs.size(); 1528 1529 Offset *= EntrySize; 1530 1531 return (uintptr_t)((char *)JumpTableBase + Offset); 1532} 1533 1534void JITEmitter::EmittedFunctionConfig::onDelete( 1535 JITEmitter *Emitter, const Function *F) { 1536 Emitter->deallocateMemForFunction(F); 1537} 1538void JITEmitter::EmittedFunctionConfig::onRAUW( 1539 JITEmitter *, const Function*, const Function*) { 1540 llvm_unreachable("The JIT doesn't know how to handle a" 1541 " RAUW on a value it has emitted."); 1542} 1543 1544 1545//===----------------------------------------------------------------------===// 1546// Public interface to this file 1547//===----------------------------------------------------------------------===// 1548 1549JITCodeEmitter *JIT::createEmitter(JIT &jit, JITMemoryManager *JMM, 1550 TargetMachine &tm) { 1551 return new JITEmitter(jit, JMM, tm); 1552} 1553 1554// getPointerToNamedFunction - This function is used as a global wrapper to 1555// JIT::getPointerToNamedFunction for the purpose of resolving symbols when 1556// bugpoint is debugging the JIT. In that scenario, we are loading an .so and 1557// need to resolve function(s) that are being mis-codegenerated, so we need to 1558// resolve their addresses at runtime, and this is the way to do it. 1559extern "C" { 1560 void *getPointerToNamedFunction(const char *Name) { 1561 if (Function *F = TheJIT->FindFunctionNamed(Name)) 1562 return TheJIT->getPointerToFunction(F); 1563 return TheJIT->getPointerToNamedFunction(Name); 1564 } 1565} 1566 1567// getPointerToFunctionOrStub - If the specified function has been 1568// code-gen'd, return a pointer to the function. If not, compile it, or use 1569// a stub to implement lazy compilation if available. 1570// 1571void *JIT::getPointerToFunctionOrStub(Function *F) { 1572 // If we have already code generated the function, just return the address. 1573 if (void *Addr = getPointerToGlobalIfAvailable(F)) 1574 return Addr; 1575 1576 // Get a stub if the target supports it. 1577 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?"); 1578 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter()); 1579 return JE->getJITResolver().getFunctionStub(F); 1580} 1581 1582void JIT::updateFunctionStub(Function *F) { 1583 // Get the empty stub we generated earlier. 1584 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?"); 1585 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter()); 1586 void *Stub = JE->getJITResolver().getFunctionStub(F); 1587 1588 // Tell the target jit info to rewrite the stub at the specified address, 1589 // rather than creating a new one. 1590 void *Addr = getPointerToGlobalIfAvailable(F); 1591 getJITInfo().emitFunctionStubAtAddr(F, Addr, Stub, *getCodeEmitter()); 1592} 1593 1594/// updateDlsymStubTable - Emit the data necessary to relocate the stubs 1595/// that were emitted during code generation. 1596/// 1597void JIT::updateDlsymStubTable() { 1598 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?"); 1599 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter()); 1600 1601 SmallVector<GlobalValue*, 8> GVs; 1602 SmallVector<void*, 8> Ptrs; 1603 const StringMap<void *> &ExtFns = JE->getExternalFnStubs(); 1604 1605 JE->getJITResolver().getRelocatableGVs(GVs, Ptrs); 1606 1607 unsigned nStubs = GVs.size() + ExtFns.size(); 1608 1609 // If there are no relocatable stubs, return. 1610 if (nStubs == 0) 1611 return; 1612 1613 // If there are no new relocatable stubs, return. 1614 void *CurTable = JE->getMemMgr()->getDlsymTable(); 1615 if (CurTable && (*(unsigned *)CurTable == nStubs)) 1616 return; 1617 1618 // Calculate the size of the stub info 1619 unsigned offset = 4 + 4 * nStubs + sizeof(intptr_t) * nStubs; 1620 1621 SmallVector<unsigned, 8> Offsets; 1622 for (unsigned i = 0; i != GVs.size(); ++i) { 1623 Offsets.push_back(offset); 1624 offset += GVs[i]->getName().size() + 1; 1625 } 1626 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end(); 1627 i != e; ++i) { 1628 Offsets.push_back(offset); 1629 offset += strlen(i->first()) + 1; 1630 } 1631 1632 // Allocate space for the new "stub", which contains the dlsym table. 1633 JE->startGVStub(0, offset, 4); 1634 1635 // Emit the number of records 1636 JE->emitInt32(nStubs); 1637 1638 // Emit the string offsets 1639 for (unsigned i = 0; i != nStubs; ++i) 1640 JE->emitInt32(Offsets[i]); 1641 1642 // Emit the pointers. Verify that they are at least 2-byte aligned, and set 1643 // the low bit to 0 == GV, 1 == Function, so that the client code doing the 1644 // relocation can write the relocated pointer at the appropriate place in 1645 // the stub. 1646 for (unsigned i = 0; i != GVs.size(); ++i) { 1647 intptr_t Ptr = (intptr_t)Ptrs[i]; 1648 assert((Ptr & 1) == 0 && "Stub pointers must be at least 2-byte aligned!"); 1649 1650 if (isa<Function>(GVs[i])) 1651 Ptr |= (intptr_t)1; 1652 1653 if (sizeof(Ptr) == 8) 1654 JE->emitInt64(Ptr); 1655 else 1656 JE->emitInt32(Ptr); 1657 } 1658 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end(); 1659 i != e; ++i) { 1660 intptr_t Ptr = (intptr_t)i->second | 1; 1661 1662 if (sizeof(Ptr) == 8) 1663 JE->emitInt64(Ptr); 1664 else 1665 JE->emitInt32(Ptr); 1666 } 1667 1668 // Emit the strings. 1669 for (unsigned i = 0; i != GVs.size(); ++i) 1670 JE->emitString(GVs[i]->getName()); 1671 for (StringMapConstIterator<void*> i = ExtFns.begin(), e = ExtFns.end(); 1672 i != e; ++i) 1673 JE->emitString(i->first()); 1674 1675 // Tell the JIT memory manager where it is. The JIT Memory Manager will 1676 // deallocate space for the old one, if one existed. 1677 JE->getMemMgr()->SetDlsymTable(JE->finishGVStub(0)); 1678} 1679 1680/// freeMachineCodeForFunction - release machine code memory for given Function. 1681/// 1682void JIT::freeMachineCodeForFunction(Function *F) { 1683 // Delete translation for this from the ExecutionEngine, so it will get 1684 // retranslated next time it is used. 1685 updateGlobalMapping(F, 0); 1686 1687 // Free the actual memory for the function body and related stuff. 1688 assert(isa<JITEmitter>(JCE) && "Unexpected MCE?"); 1689 cast<JITEmitter>(JCE)->deallocateMemForFunction(F); 1690} 1691