1 //===-- JITEmitter.cpp - Write machine code to executable memory ----------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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.
13 //===----------------------------------------------------------------------===//
15 #define DEBUG_TYPE "jit"
17 #include "JITDwarfEmitter.h"
18 #include "llvm/Constants.h"
19 #include "llvm/Module.h"
20 #include "llvm/DerivedTypes.h"
21 #include "llvm/CodeGen/MachineCodeEmitter.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/JITMemoryManager.h"
28 #include "llvm/ExecutionEngine/GenericValue.h"
29 #include "llvm/Target/TargetData.h"
30 #include "llvm/Target/TargetJITInfo.h"
31 #include "llvm/Target/TargetMachine.h"
32 #include "llvm/Target/TargetOptions.h"
33 #include "llvm/Support/Debug.h"
34 #include "llvm/Support/MutexGuard.h"
35 #include "llvm/System/Disassembler.h"
36 #include "llvm/System/Memory.h"
37 #include "llvm/Target/TargetInstrInfo.h"
38 #include "llvm/ADT/SmallPtrSet.h"
39 #include "llvm/ADT/SmallVector.h"
40 #include "llvm/ADT/Statistic.h"
47 STATISTIC(NumBytes, "Number of bytes of machine code compiled");
48 STATISTIC(NumRelos, "Number of relocations applied");
49 static JIT *TheJIT = 0;
52 //===----------------------------------------------------------------------===//
53 // JIT lazy compilation code.
56 class JITResolverState {
58 /// FunctionToStubMap - Keep track of the stub created for a particular
59 /// function so that we can reuse them if necessary.
60 std::map<Function*, void*> FunctionToStubMap;
62 /// StubToFunctionMap - Keep track of the function that each stub
64 std::map<void*, Function*> StubToFunctionMap;
66 /// GlobalToIndirectSymMap - Keep track of the indirect symbol created for a
67 /// particular GlobalVariable so that we can reuse them if necessary.
68 std::map<GlobalValue*, void*> GlobalToIndirectSymMap;
71 std::map<Function*, void*>& getFunctionToStubMap(const MutexGuard& locked) {
72 assert(locked.holds(TheJIT->lock));
73 return FunctionToStubMap;
76 std::map<void*, Function*>& getStubToFunctionMap(const MutexGuard& locked) {
77 assert(locked.holds(TheJIT->lock));
78 return StubToFunctionMap;
81 std::map<GlobalValue*, void*>&
82 getGlobalToIndirectSymMap(const MutexGuard& locked) {
83 assert(locked.holds(TheJIT->lock));
84 return GlobalToIndirectSymMap;
88 /// JITResolver - Keep track of, and resolve, call sites for functions that
89 /// have not yet been compiled.
91 /// LazyResolverFn - The target lazy resolver function that we actually
92 /// rewrite instructions to use.
93 TargetJITInfo::LazyResolverFn LazyResolverFn;
95 JITResolverState state;
97 /// ExternalFnToStubMap - This is the equivalent of FunctionToStubMap for
98 /// external functions.
99 std::map<void*, void*> ExternalFnToStubMap;
101 //map addresses to indexes in the GOT
102 std::map<void*, unsigned> revGOTMap;
103 unsigned nextGOTIndex;
105 static JITResolver *TheJITResolver;
107 explicit JITResolver(JIT &jit) : nextGOTIndex(0) {
110 LazyResolverFn = jit.getJITInfo().getLazyResolverFunction(JITCompilerFn);
111 assert(TheJITResolver == 0 && "Multiple JIT resolvers?");
112 TheJITResolver = this;
119 /// getFunctionStubIfAvailable - This returns a pointer to a function stub
120 /// if it has already been created.
121 void *getFunctionStubIfAvailable(Function *F);
123 /// getFunctionStub - This returns a pointer to a function stub, creating
124 /// one on demand as needed. If empty is true, create a function stub
125 /// pointing at address 0, to be filled in later.
126 void *getFunctionStub(Function *F);
128 /// getExternalFunctionStub - Return a stub for the function at the
129 /// specified address, created lazily on demand.
130 void *getExternalFunctionStub(void *FnAddr);
132 /// getGlobalValueIndirectSym - Return an indirect symbol containing the
133 /// specified GV address.
134 void *getGlobalValueIndirectSym(GlobalValue *V, void *GVAddress);
136 /// AddCallbackAtLocation - If the target is capable of rewriting an
137 /// instruction without the use of a stub, record the location of the use so
138 /// we know which function is being used at the location.
139 void *AddCallbackAtLocation(Function *F, void *Location) {
140 MutexGuard locked(TheJIT->lock);
141 /// Get the target-specific JIT resolver function.
142 state.getStubToFunctionMap(locked)[Location] = F;
143 return (void*)(intptr_t)LazyResolverFn;
146 void getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs,
147 SmallVectorImpl<void*> &Ptrs);
149 GlobalValue *invalidateStub(void *Stub);
151 /// getGOTIndexForAddress - Return a new or existing index in the GOT for
152 /// an address. This function only manages slots, it does not manage the
153 /// contents of the slots or the memory associated with the GOT.
154 unsigned getGOTIndexForAddr(void *addr);
156 /// JITCompilerFn - This function is called to resolve a stub to a compiled
157 /// address. If the LLVM Function corresponding to the stub has not yet
158 /// been compiled, this function compiles it first.
159 static void *JITCompilerFn(void *Stub);
163 JITResolver *JITResolver::TheJITResolver = 0;
165 /// getFunctionStubIfAvailable - This returns a pointer to a function stub
166 /// if it has already been created.
167 void *JITResolver::getFunctionStubIfAvailable(Function *F) {
168 MutexGuard locked(TheJIT->lock);
170 // If we already have a stub for this function, recycle it.
171 void *&Stub = state.getFunctionToStubMap(locked)[F];
175 /// getFunctionStub - This returns a pointer to a function stub, creating
176 /// one on demand as needed.
177 void *JITResolver::getFunctionStub(Function *F) {
178 MutexGuard locked(TheJIT->lock);
180 // If we already have a stub for this function, recycle it.
181 void *&Stub = state.getFunctionToStubMap(locked)[F];
182 if (Stub) return Stub;
184 // Call the lazy resolver function unless we are JIT'ing non-lazily, in which
185 // case we must resolve the symbol now.
186 void *Actual = TheJIT->isLazyCompilationDisabled()
187 ? (void *)0 : (void *)(intptr_t)LazyResolverFn;
189 // If this is an external declaration, attempt to resolve the address now
190 // to place in the stub.
191 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode()) {
192 Actual = TheJIT->getPointerToFunction(F);
194 // If we resolved the symbol to a null address (eg. a weak external)
195 // don't emit a stub. Return a null pointer to the application. If dlsym
196 // stubs are enabled, not being able to resolve the address is not
198 if (!Actual && !TheJIT->areDlsymStubsEnabled()) return 0;
201 // Codegen a new stub, calling the lazy resolver or the actual address of the
202 // external function, if it was resolved.
203 Stub = TheJIT->getJITInfo().emitFunctionStub(F, Actual,
204 *TheJIT->getCodeEmitter());
206 if (Actual != (void*)(intptr_t)LazyResolverFn) {
207 // If we are getting the stub for an external function, we really want the
208 // address of the stub in the GlobalAddressMap for the JIT, not the address
209 // of the external function.
210 TheJIT->updateGlobalMapping(F, Stub);
213 DOUT << "JIT: Stub emitted at [" << Stub << "] for function '"
214 << F->getName() << "'\n";
216 // Finally, keep track of the stub-to-Function mapping so that the
217 // JITCompilerFn knows which function to compile!
218 state.getStubToFunctionMap(locked)[Stub] = F;
220 // If we are JIT'ing non-lazily but need to call a function that does not
221 // exist yet, add it to the JIT's work list so that we can fill in the stub
223 if (!Actual && TheJIT->isLazyCompilationDisabled())
224 if (!F->isDeclaration() || F->hasNotBeenReadFromBitcode())
225 TheJIT->addPendingFunction(F);
230 /// getGlobalValueIndirectSym - Return a lazy pointer containing the specified
232 void *JITResolver::getGlobalValueIndirectSym(GlobalValue *GV, void *GVAddress) {
233 MutexGuard locked(TheJIT->lock);
235 // If we already have a stub for this global variable, recycle it.
236 void *&IndirectSym = state.getGlobalToIndirectSymMap(locked)[GV];
237 if (IndirectSym) return IndirectSym;
239 // Otherwise, codegen a new indirect symbol.
240 IndirectSym = TheJIT->getJITInfo().emitGlobalValueIndirectSym(GV, GVAddress,
241 *TheJIT->getCodeEmitter());
243 DOUT << "JIT: Indirect symbol emitted at [" << IndirectSym << "] for GV '"
244 << GV->getName() << "'\n";
249 /// getExternalFunctionStub - Return a stub for the function at the
250 /// specified address, created lazily on demand.
251 void *JITResolver::getExternalFunctionStub(void *FnAddr) {
252 // If we already have a stub for this function, recycle it.
253 void *&Stub = ExternalFnToStubMap[FnAddr];
254 if (Stub) return Stub;
256 Stub = TheJIT->getJITInfo().emitFunctionStub(0, FnAddr,
257 *TheJIT->getCodeEmitter());
259 DOUT << "JIT: Stub emitted at [" << Stub
260 << "] for external function at '" << FnAddr << "'\n";
264 unsigned JITResolver::getGOTIndexForAddr(void* addr) {
265 unsigned idx = revGOTMap[addr];
267 idx = ++nextGOTIndex;
268 revGOTMap[addr] = idx;
269 DOUT << "JIT: Adding GOT entry " << idx << " for addr [" << addr << "]\n";
274 void JITResolver::getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs,
275 SmallVectorImpl<void*> &Ptrs) {
276 MutexGuard locked(TheJIT->lock);
278 std::map<Function*,void*> &FM = state.getFunctionToStubMap(locked);
279 std::map<GlobalValue*,void*> &GM = state.getGlobalToIndirectSymMap(locked);
281 for (std::map<Function*,void*>::iterator i = FM.begin(), e = FM.end();
283 Function *F = i->first;
284 if (F->isDeclaration() && F->hasExternalLinkage()) {
285 GVs.push_back(i->first);
286 Ptrs.push_back(i->second);
289 for (std::map<GlobalValue*,void*>::iterator i = GM.begin(), e = GM.end();
291 GVs.push_back(i->first);
292 Ptrs.push_back(i->second);
296 GlobalValue *JITResolver::invalidateStub(void *Stub) {
297 MutexGuard locked(TheJIT->lock);
299 std::map<Function*,void*> &FM = state.getFunctionToStubMap(locked);
300 std::map<void*,Function*> &SM = state.getStubToFunctionMap(locked);
301 std::map<GlobalValue*,void*> &GM = state.getGlobalToIndirectSymMap(locked);
303 // Look up the cheap way first, to see if it's a function stub we are
304 // invalidating. If so, remove it from both the forward and reverse maps.
305 if (SM.find(Stub) != SM.end()) {
306 Function *F = SM[Stub];
312 // Otherwise, it must be an indirect symbol stub. Find it and remove it.
313 for (std::map<GlobalValue*,void*>::iterator i = GM.begin(), e = GM.end();
315 if (i->second != Stub)
317 GlobalValue *GV = i->first;
325 /// JITCompilerFn - This function is called when a lazy compilation stub has
326 /// been entered. It looks up which function this stub corresponds to, compiles
327 /// it if necessary, then returns the resultant function pointer.
328 void *JITResolver::JITCompilerFn(void *Stub) {
329 JITResolver &JR = *TheJITResolver;
335 // Only lock for getting the Function. The call getPointerToFunction made
336 // in this function might trigger function materializing, which requires
337 // JIT lock to be unlocked.
338 MutexGuard locked(TheJIT->lock);
340 // The address given to us for the stub may not be exactly right, it might be
341 // a little bit after the stub. As such, use upper_bound to find it.
342 std::map<void*, Function*>::iterator I =
343 JR.state.getStubToFunctionMap(locked).upper_bound(Stub);
344 assert(I != JR.state.getStubToFunctionMap(locked).begin() &&
345 "This is not a known stub!");
347 ActualPtr = I->first;
350 // If we have already code generated the function, just return the address.
351 void *Result = TheJIT->getPointerToGlobalIfAvailable(F);
354 // Otherwise we don't have it, do lazy compilation now.
356 // If lazy compilation is disabled, emit a useful error message and abort.
357 if (TheJIT->isLazyCompilationDisabled()) {
358 cerr << "LLVM JIT requested to do lazy compilation of function '"
359 << F->getName() << "' when lazy compiles are disabled!\n";
363 // We might like to remove the stub from the StubToFunction map.
364 // We can't do that! Multiple threads could be stuck, waiting to acquire the
365 // lock above. As soon as the 1st function finishes compiling the function,
366 // the next one will be released, and needs to be able to find the function
368 //JR.state.getStubToFunctionMap(locked).erase(I);
370 DOUT << "JIT: Lazily resolving function '" << F->getName()
371 << "' In stub ptr = " << Stub << " actual ptr = "
372 << ActualPtr << "\n";
374 Result = TheJIT->getPointerToFunction(F);
377 // Reacquire the lock to erase the stub in the map.
378 MutexGuard locked(TheJIT->lock);
380 // We don't need to reuse this stub in the future, as F is now compiled.
381 JR.state.getFunctionToStubMap(locked).erase(F);
383 // FIXME: We could rewrite all references to this stub if we knew them.
385 // What we will do is set the compiled function address to map to the
386 // same GOT entry as the stub so that later clients may update the GOT
387 // if they see it still using the stub address.
388 // Note: this is done so the Resolver doesn't have to manage GOT memory
389 // Do this without allocating map space if the target isn't using a GOT
390 if(JR.revGOTMap.find(Stub) != JR.revGOTMap.end())
391 JR.revGOTMap[Result] = JR.revGOTMap[Stub];
396 //===----------------------------------------------------------------------===//
397 // Function Index Support
399 // On MacOS we generate an index of currently JIT'd functions so that
400 // performance tools can determine a symbol name and accurate code range for a
401 // PC value. Because performance tools are generally asynchronous, the code
402 // below is written with the hope that it could be interrupted at any time and
403 // have useful answers. However, we don't go crazy with atomic operations, we
404 // just do a "reasonable effort".
406 #define ENABLE_JIT_SYMBOL_TABLE 0
409 /// JitSymbolEntry - Each function that is JIT compiled results in one of these
410 /// being added to an array of symbols. This indicates the name of the function
411 /// as well as the address range it occupies. This allows the client to map
412 /// from a PC value to the name of the function.
413 struct JitSymbolEntry {
414 const char *FnName; // FnName - a strdup'd string.
420 struct JitSymbolTable {
421 /// NextPtr - This forms a linked list of JitSymbolTable entries. This
422 /// pointer is not used right now, but might be used in the future. Consider
423 /// it reserved for future use.
424 JitSymbolTable *NextPtr;
426 /// Symbols - This is an array of JitSymbolEntry entries. Only the first
427 /// 'NumSymbols' symbols are valid.
428 JitSymbolEntry *Symbols;
430 /// NumSymbols - This indicates the number entries in the Symbols array that
434 /// NumAllocated - This indicates the amount of space we have in the Symbols
435 /// array. This is a private field that should not be read by external tools.
436 unsigned NumAllocated;
439 #if ENABLE_JIT_SYMBOL_TABLE
440 JitSymbolTable *__jitSymbolTable;
443 static void AddFunctionToSymbolTable(const char *FnName,
444 void *FnStart, intptr_t FnSize) {
445 assert(FnName != 0 && FnStart != 0 && "Bad symbol to add");
446 JitSymbolTable **SymTabPtrPtr = 0;
447 #if !ENABLE_JIT_SYMBOL_TABLE
450 SymTabPtrPtr = &__jitSymbolTable;
453 // If this is the first entry in the symbol table, add the JitSymbolTable
455 if (*SymTabPtrPtr == 0) {
456 JitSymbolTable *New = new JitSymbolTable();
460 New->NumAllocated = 0;
464 JitSymbolTable *SymTabPtr = *SymTabPtrPtr;
466 // If we have space in the table, reallocate the table.
467 if (SymTabPtr->NumSymbols >= SymTabPtr->NumAllocated) {
468 // If we don't have space, reallocate the table.
469 unsigned NewSize = std::max(64U, SymTabPtr->NumAllocated*2);
470 JitSymbolEntry *NewSymbols = new JitSymbolEntry[NewSize];
471 JitSymbolEntry *OldSymbols = SymTabPtr->Symbols;
473 // Copy the old entries over.
474 memcpy(NewSymbols, OldSymbols, SymTabPtr->NumSymbols*sizeof(OldSymbols[0]));
476 // Swap the new symbols in, delete the old ones.
477 SymTabPtr->Symbols = NewSymbols;
478 SymTabPtr->NumAllocated = NewSize;
479 delete [] OldSymbols;
482 // Otherwise, we have enough space, just tack it onto the end of the array.
483 JitSymbolEntry &Entry = SymTabPtr->Symbols[SymTabPtr->NumSymbols];
484 Entry.FnName = strdup(FnName);
485 Entry.FnStart = FnStart;
486 Entry.FnSize = FnSize;
487 ++SymTabPtr->NumSymbols;
490 static void RemoveFunctionFromSymbolTable(void *FnStart) {
491 assert(FnStart && "Invalid function pointer");
492 JitSymbolTable **SymTabPtrPtr = 0;
493 #if !ENABLE_JIT_SYMBOL_TABLE
496 SymTabPtrPtr = &__jitSymbolTable;
499 JitSymbolTable *SymTabPtr = *SymTabPtrPtr;
500 JitSymbolEntry *Symbols = SymTabPtr->Symbols;
502 // Scan the table to find its index. The table is not sorted, so do a linear
505 for (Index = 0; Symbols[Index].FnStart != FnStart; ++Index)
506 assert(Index != SymTabPtr->NumSymbols && "Didn't find function!");
508 // Once we have an index, we know to nuke this entry, overwrite it with the
509 // entry at the end of the array, making the last entry redundant.
510 const char *OldName = Symbols[Index].FnName;
511 Symbols[Index] = Symbols[SymTabPtr->NumSymbols-1];
512 free((void*)OldName);
514 // Drop the number of symbols in the table.
515 --SymTabPtr->NumSymbols;
517 // Finally, if we deleted the final symbol, deallocate the table itself.
518 if (SymTabPtr->NumSymbols != 0)
526 //===----------------------------------------------------------------------===//
530 /// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is
531 /// used to output functions to memory for execution.
532 class JITEmitter : public MachineCodeEmitter {
533 JITMemoryManager *MemMgr;
535 // When outputting a function stub in the context of some other function, we
536 // save BufferBegin/BufferEnd/CurBufferPtr here.
537 unsigned char *SavedBufferBegin, *SavedBufferEnd, *SavedCurBufferPtr;
539 /// Relocations - These are the relocations that the function needs, as
541 std::vector<MachineRelocation> Relocations;
543 /// MBBLocations - This vector is a mapping from MBB ID's to their address.
544 /// It is filled in by the StartMachineBasicBlock callback and queried by
545 /// the getMachineBasicBlockAddress callback.
546 std::vector<uintptr_t> MBBLocations;
548 /// ConstantPool - The constant pool for the current function.
550 MachineConstantPool *ConstantPool;
552 /// ConstantPoolBase - A pointer to the first entry in the constant pool.
554 void *ConstantPoolBase;
556 /// JumpTable - The jump tables for the current function.
558 MachineJumpTableInfo *JumpTable;
560 /// JumpTableBase - A pointer to the first entry in the jump table.
564 /// Resolver - This contains info about the currently resolved functions.
565 JITResolver Resolver;
567 /// DE - The dwarf emitter for the jit.
570 /// LabelLocations - This vector is a mapping from Label ID's to their
572 std::vector<uintptr_t> LabelLocations;
574 /// MMI - Machine module info for exception informations
575 MachineModuleInfo* MMI;
577 // GVSet - a set to keep track of which globals have been seen
578 SmallPtrSet<const GlobalVariable*, 8> GVSet;
580 // CurFn - The llvm function being emitted. Only valid during
582 const Function *CurFn;
584 // CurFnStubUses - For a given Function, a vector of stubs that it
585 // references. This facilitates the JIT detecting that a stub is no
586 // longer used, so that it may be deallocated.
587 DenseMap<const Function *, SmallVector<void*, 1> > CurFnStubUses;
589 // StubFnRefs - For a given pointer to a stub, a set of Functions which
590 // reference the stub. When the count of a stub's references drops to zero,
591 // the stub is unused.
592 DenseMap<void *, SmallPtrSet<const Function*, 1> > StubFnRefs;
595 JITEmitter(JIT &jit, JITMemoryManager *JMM) : Resolver(jit), CurFn(0) {
596 MemMgr = JMM ? JMM : JITMemoryManager::CreateDefaultMemManager();
597 if (jit.getJITInfo().needsGOT()) {
598 MemMgr->AllocateGOT();
599 DOUT << "JIT is managing a GOT\n";
602 if (ExceptionHandling) DE = new JITDwarfEmitter(jit);
606 if (ExceptionHandling) delete DE;
609 /// classof - Methods for support type inquiry through isa, cast, and
612 static inline bool classof(const JITEmitter*) { return true; }
613 static inline bool classof(const MachineCodeEmitter*) { return true; }
615 JITResolver &getJITResolver() { return Resolver; }
617 virtual void startFunction(MachineFunction &F);
618 virtual bool finishFunction(MachineFunction &F);
620 void emitConstantPool(MachineConstantPool *MCP);
621 void initJumpTableInfo(MachineJumpTableInfo *MJTI);
622 void emitJumpTableInfo(MachineJumpTableInfo *MJTI);
624 virtual void startGVStub(const GlobalValue* GV, unsigned StubSize,
625 unsigned Alignment = 1);
626 virtual void startGVStub(const GlobalValue* GV, void *Buffer,
628 virtual void* finishGVStub(const GlobalValue *GV);
630 /// allocateSpace - Reserves space in the current block if any, or
631 /// allocate a new one of the given size.
632 virtual void *allocateSpace(uintptr_t Size, unsigned Alignment);
634 virtual void addRelocation(const MachineRelocation &MR) {
635 Relocations.push_back(MR);
638 virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {
639 if (MBBLocations.size() <= (unsigned)MBB->getNumber())
640 MBBLocations.resize((MBB->getNumber()+1)*2);
641 MBBLocations[MBB->getNumber()] = getCurrentPCValue();
642 DOUT << "JIT: Emitting BB" << MBB->getNumber() << " at ["
643 << (void*) getCurrentPCValue() << "]\n";
646 virtual uintptr_t getConstantPoolEntryAddress(unsigned Entry) const;
647 virtual uintptr_t getJumpTableEntryAddress(unsigned Entry) const;
649 virtual uintptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const {
650 assert(MBBLocations.size() > (unsigned)MBB->getNumber() &&
651 MBBLocations[MBB->getNumber()] && "MBB not emitted!");
652 return MBBLocations[MBB->getNumber()];
655 void AddStubToCurrentFunction(void *Stub);
657 /// deallocateMemForFunction - Deallocate all memory for the specified
659 void deallocateMemForFunction(Function *F);
661 virtual void emitLabel(uint64_t LabelID) {
662 if (LabelLocations.size() <= LabelID)
663 LabelLocations.resize((LabelID+1)*2);
664 LabelLocations[LabelID] = getCurrentPCValue();
667 virtual uintptr_t getLabelAddress(uint64_t LabelID) const {
668 assert(LabelLocations.size() > (unsigned)LabelID &&
669 LabelLocations[LabelID] && "Label not emitted!");
670 return LabelLocations[LabelID];
673 virtual void setModuleInfo(MachineModuleInfo* Info) {
675 if (ExceptionHandling) DE->setModuleInfo(Info);
678 void setMemoryExecutable(void) {
679 MemMgr->setMemoryExecutable();
682 JITMemoryManager *getMemMgr(void) const { return MemMgr; }
685 void *getPointerToGlobal(GlobalValue *GV, void *Reference, bool NoNeedStub);
686 void *getPointerToGVIndirectSym(GlobalValue *V, void *Reference,
688 unsigned addSizeOfGlobal(const GlobalVariable *GV, unsigned Size);
689 unsigned addSizeOfGlobalsInConstantVal(const Constant *C, unsigned Size);
690 unsigned addSizeOfGlobalsInInitializer(const Constant *Init, unsigned Size);
691 unsigned GetSizeOfGlobalsInBytes(MachineFunction &MF);
695 void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference,
696 bool DoesntNeedStub) {
697 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
698 return TheJIT->getOrEmitGlobalVariable(GV);
700 if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
701 return TheJIT->getPointerToGlobal(GA->resolveAliasedGlobal(false));
703 // If we have already compiled the function, return a pointer to its body.
704 Function *F = cast<Function>(V);
706 if (!DoesntNeedStub && !TheJIT->isLazyCompilationDisabled()) {
707 // Return the function stub if it's already created.
708 ResultPtr = Resolver.getFunctionStubIfAvailable(F);
710 AddStubToCurrentFunction(ResultPtr);
712 ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F);
714 if (ResultPtr) return ResultPtr;
716 // If this is an external function pointer, we can force the JIT to
717 // 'compile' it, which really just adds it to the map. In dlsym mode,
718 // external functions are forced through a stub, regardless of reloc type.
719 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode() &&
720 DoesntNeedStub && !TheJIT->areDlsymStubsEnabled())
721 return TheJIT->getPointerToFunction(F);
723 // Okay, the function has not been compiled yet, if the target callback
724 // mechanism is capable of rewriting the instruction directly, prefer to do
725 // that instead of emitting a stub. This uses the lazy resolver, so is not
726 // legal if lazy compilation is disabled.
727 if (DoesntNeedStub && !TheJIT->isLazyCompilationDisabled())
728 return Resolver.AddCallbackAtLocation(F, Reference);
730 // Otherwise, we have to emit a stub.
731 void *StubAddr = Resolver.getFunctionStub(F);
733 // Add the stub to the current function's list of referenced stubs, so we can
734 // deallocate them if the current function is ever freed. It's possible to
735 // return null from getFunctionStub in the case of a weak extern that fails
738 AddStubToCurrentFunction(StubAddr);
743 void *JITEmitter::getPointerToGVIndirectSym(GlobalValue *V, void *Reference,
745 // Make sure GV is emitted first, and create a stub containing the fully
747 void *GVAddress = getPointerToGlobal(V, Reference, true);
748 void *StubAddr = Resolver.getGlobalValueIndirectSym(V, GVAddress);
750 // Add the stub to the current function's list of referenced stubs, so we can
751 // deallocate them if the current function is ever freed.
752 AddStubToCurrentFunction(StubAddr);
757 void JITEmitter::AddStubToCurrentFunction(void *StubAddr) {
758 if (!TheJIT->areDlsymStubsEnabled())
761 assert(CurFn && "Stub added to current function, but current function is 0!");
763 SmallVectorImpl<void*> &StubsUsed = CurFnStubUses[CurFn];
764 StubsUsed.push_back(StubAddr);
766 SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[StubAddr];
767 FnRefs.insert(CurFn);
770 static unsigned GetConstantPoolSizeInBytes(MachineConstantPool *MCP) {
771 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
772 if (Constants.empty()) return 0;
774 MachineConstantPoolEntry CPE = Constants.back();
775 unsigned Size = CPE.Offset;
776 const Type *Ty = CPE.isMachineConstantPoolEntry()
777 ? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal->getType();
778 Size += TheJIT->getTargetData()->getTypePaddedSize(Ty);
782 static unsigned GetJumpTableSizeInBytes(MachineJumpTableInfo *MJTI) {
783 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
784 if (JT.empty()) return 0;
786 unsigned NumEntries = 0;
787 for (unsigned i = 0, e = JT.size(); i != e; ++i)
788 NumEntries += JT[i].MBBs.size();
790 unsigned EntrySize = MJTI->getEntrySize();
792 return NumEntries * EntrySize;
795 static uintptr_t RoundUpToAlign(uintptr_t Size, unsigned Alignment) {
796 if (Alignment == 0) Alignment = 1;
797 // Since we do not know where the buffer will be allocated, be pessimistic.
798 return Size + Alignment;
801 /// addSizeOfGlobal - add the size of the global (plus any alignment padding)
802 /// into the running total Size.
804 unsigned JITEmitter::addSizeOfGlobal(const GlobalVariable *GV, unsigned Size) {
805 const Type *ElTy = GV->getType()->getElementType();
806 size_t GVSize = (size_t)TheJIT->getTargetData()->getTypePaddedSize(ElTy);
808 (size_t)TheJIT->getTargetData()->getPreferredAlignment(GV);
809 DOUT << "JIT: Adding in size " << GVSize << " alignment " << GVAlign;
811 // Assume code section ends with worst possible alignment, so first
812 // variable needs maximal padding.
815 Size = ((Size+GVAlign-1)/GVAlign)*GVAlign;
820 /// addSizeOfGlobalsInConstantVal - find any globals that we haven't seen yet
821 /// but are referenced from the constant; put them in GVSet and add their
822 /// size into the running total Size.
824 unsigned JITEmitter::addSizeOfGlobalsInConstantVal(const Constant *C,
826 // If its undefined, return the garbage.
827 if (isa<UndefValue>(C))
830 // If the value is a ConstantExpr
831 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
832 Constant *Op0 = CE->getOperand(0);
833 switch (CE->getOpcode()) {
834 case Instruction::GetElementPtr:
835 case Instruction::Trunc:
836 case Instruction::ZExt:
837 case Instruction::SExt:
838 case Instruction::FPTrunc:
839 case Instruction::FPExt:
840 case Instruction::UIToFP:
841 case Instruction::SIToFP:
842 case Instruction::FPToUI:
843 case Instruction::FPToSI:
844 case Instruction::PtrToInt:
845 case Instruction::IntToPtr:
846 case Instruction::BitCast: {
847 Size = addSizeOfGlobalsInConstantVal(Op0, Size);
850 case Instruction::Add:
851 case Instruction::Sub:
852 case Instruction::Mul:
853 case Instruction::UDiv:
854 case Instruction::SDiv:
855 case Instruction::URem:
856 case Instruction::SRem:
857 case Instruction::And:
858 case Instruction::Or:
859 case Instruction::Xor: {
860 Size = addSizeOfGlobalsInConstantVal(Op0, Size);
861 Size = addSizeOfGlobalsInConstantVal(CE->getOperand(1), Size);
865 cerr << "ConstantExpr not handled: " << *CE << "\n";
871 if (C->getType()->getTypeID() == Type::PointerTyID)
872 if (const GlobalVariable* GV = dyn_cast<GlobalVariable>(C))
873 if (GVSet.insert(GV))
874 Size = addSizeOfGlobal(GV, Size);
879 /// addSizeOfGLobalsInInitializer - handle any globals that we haven't seen yet
880 /// but are referenced from the given initializer.
882 unsigned JITEmitter::addSizeOfGlobalsInInitializer(const Constant *Init,
884 if (!isa<UndefValue>(Init) &&
885 !isa<ConstantVector>(Init) &&
886 !isa<ConstantAggregateZero>(Init) &&
887 !isa<ConstantArray>(Init) &&
888 !isa<ConstantStruct>(Init) &&
889 Init->getType()->isFirstClassType())
890 Size = addSizeOfGlobalsInConstantVal(Init, Size);
894 /// GetSizeOfGlobalsInBytes - walk the code for the function, looking for
895 /// globals; then walk the initializers of those globals looking for more.
896 /// If their size has not been considered yet, add it into the running total
899 unsigned JITEmitter::GetSizeOfGlobalsInBytes(MachineFunction &MF) {
903 for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
905 for (MachineBasicBlock::const_iterator I = MBB->begin(), E = MBB->end();
907 const TargetInstrDesc &Desc = I->getDesc();
908 const MachineInstr &MI = *I;
909 unsigned NumOps = Desc.getNumOperands();
910 for (unsigned CurOp = 0; CurOp < NumOps; CurOp++) {
911 const MachineOperand &MO = MI.getOperand(CurOp);
913 GlobalValue* V = MO.getGlobal();
914 const GlobalVariable *GV = dyn_cast<const GlobalVariable>(V);
917 // If seen in previous function, it will have an entry here.
918 if (TheJIT->getPointerToGlobalIfAvailable(GV))
920 // If seen earlier in this function, it will have an entry here.
921 // FIXME: it should be possible to combine these tables, by
922 // assuming the addresses of the new globals in this module
923 // start at 0 (or something) and adjusting them after codegen
924 // complete. Another possibility is to grab a marker bit in GV.
925 if (GVSet.insert(GV))
926 // A variable as yet unseen. Add in its size.
927 Size = addSizeOfGlobal(GV, Size);
932 DOUT << "JIT: About to look through initializers\n";
933 // Look for more globals that are referenced only from initializers.
934 // GVSet.end is computed each time because the set can grow as we go.
935 for (SmallPtrSet<const GlobalVariable *, 8>::iterator I = GVSet.begin();
936 I != GVSet.end(); I++) {
937 const GlobalVariable* GV = *I;
938 if (GV->hasInitializer())
939 Size = addSizeOfGlobalsInInitializer(GV->getInitializer(), Size);
945 void JITEmitter::startFunction(MachineFunction &F) {
946 DOUT << "JIT: Starting CodeGen of Function "
947 << F.getFunction()->getName() << "\n";
949 uintptr_t ActualSize = 0;
950 // Set the memory writable, if it's not already
951 MemMgr->setMemoryWritable();
952 if (MemMgr->NeedsExactSize()) {
953 DOUT << "JIT: ExactSize\n";
954 const TargetInstrInfo* TII = F.getTarget().getInstrInfo();
955 MachineJumpTableInfo *MJTI = F.getJumpTableInfo();
956 MachineConstantPool *MCP = F.getConstantPool();
958 // Ensure the constant pool/jump table info is at least 4-byte aligned.
959 ActualSize = RoundUpToAlign(ActualSize, 16);
961 // Add the alignment of the constant pool
962 ActualSize = RoundUpToAlign(ActualSize,
963 1 << MCP->getConstantPoolAlignment());
965 // Add the constant pool size
966 ActualSize += GetConstantPoolSizeInBytes(MCP);
968 // Add the aligment of the jump table info
969 ActualSize = RoundUpToAlign(ActualSize, MJTI->getAlignment());
971 // Add the jump table size
972 ActualSize += GetJumpTableSizeInBytes(MJTI);
974 // Add the alignment for the function
975 ActualSize = RoundUpToAlign(ActualSize,
976 std::max(F.getFunction()->getAlignment(), 8U));
978 // Add the function size
979 ActualSize += TII->GetFunctionSizeInBytes(F);
981 DOUT << "JIT: ActualSize before globals " << ActualSize << "\n";
982 // Add the size of the globals that will be allocated after this function.
983 // These are all the ones referenced from this function that were not
984 // previously allocated.
985 ActualSize += GetSizeOfGlobalsInBytes(F);
986 DOUT << "JIT: ActualSize after globals " << ActualSize << "\n";
989 BufferBegin = CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(),
991 BufferEnd = BufferBegin+ActualSize;
993 // Ensure the constant pool/jump table info is at least 4-byte aligned.
996 emitConstantPool(F.getConstantPool());
997 initJumpTableInfo(F.getJumpTableInfo());
999 // About to start emitting the machine code for the function.
1000 emitAlignment(std::max(F.getFunction()->getAlignment(), 8U));
1001 TheJIT->updateGlobalMapping(F.getFunction(), CurBufferPtr);
1003 MBBLocations.clear();
1006 bool JITEmitter::finishFunction(MachineFunction &F) {
1007 if (CurBufferPtr == BufferEnd) {
1008 // FIXME: Allocate more space, then try again.
1009 cerr << "JIT: Ran out of space for generated machine code!\n";
1013 emitJumpTableInfo(F.getJumpTableInfo());
1015 // FnStart is the start of the text, not the start of the constant pool and
1016 // other per-function data.
1017 unsigned char *FnStart =
1018 (unsigned char *)TheJIT->getPointerToGlobalIfAvailable(F.getFunction());
1020 if (!Relocations.empty()) {
1021 CurFn = F.getFunction();
1022 NumRelos += Relocations.size();
1024 // Resolve the relocations to concrete pointers.
1025 for (unsigned i = 0, e = Relocations.size(); i != e; ++i) {
1026 MachineRelocation &MR = Relocations[i];
1027 void *ResultPtr = 0;
1028 if (!MR.letTargetResolve()) {
1029 if (MR.isExternalSymbol()) {
1030 ResultPtr = TheJIT->getPointerToNamedFunction(MR.getExternalSymbol(),
1032 DOUT << "JIT: Map \'" << MR.getExternalSymbol() << "\' to ["
1033 << ResultPtr << "]\n";
1035 // If the target REALLY wants a stub for this function, emit it now.
1036 if (!MR.doesntNeedStub())
1037 ResultPtr = Resolver.getExternalFunctionStub(ResultPtr);
1038 } else if (MR.isGlobalValue()) {
1039 ResultPtr = getPointerToGlobal(MR.getGlobalValue(),
1040 BufferBegin+MR.getMachineCodeOffset(),
1041 MR.doesntNeedStub());
1042 } else if (MR.isIndirectSymbol()) {
1043 ResultPtr = getPointerToGVIndirectSym(MR.getGlobalValue(),
1044 BufferBegin+MR.getMachineCodeOffset(),
1045 MR.doesntNeedStub());
1046 } else if (MR.isBasicBlock()) {
1047 ResultPtr = (void*)getMachineBasicBlockAddress(MR.getBasicBlock());
1048 } else if (MR.isConstantPoolIndex()) {
1049 ResultPtr = (void*)getConstantPoolEntryAddress(MR.getConstantPoolIndex());
1051 assert(MR.isJumpTableIndex());
1052 ResultPtr=(void*)getJumpTableEntryAddress(MR.getJumpTableIndex());
1055 MR.setResultPointer(ResultPtr);
1058 // if we are managing the GOT and the relocation wants an index,
1060 if (MR.isGOTRelative() && MemMgr->isManagingGOT()) {
1061 unsigned idx = Resolver.getGOTIndexForAddr(ResultPtr);
1062 MR.setGOTIndex(idx);
1063 if (((void**)MemMgr->getGOTBase())[idx] != ResultPtr) {
1064 DOUT << "JIT: GOT was out of date for " << ResultPtr
1065 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
1067 ((void**)MemMgr->getGOTBase())[idx] = ResultPtr;
1073 TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0],
1074 Relocations.size(), MemMgr->getGOTBase());
1077 // Update the GOT entry for F to point to the new code.
1078 if (MemMgr->isManagingGOT()) {
1079 unsigned idx = Resolver.getGOTIndexForAddr((void*)BufferBegin);
1080 if (((void**)MemMgr->getGOTBase())[idx] != (void*)BufferBegin) {
1081 DOUT << "JIT: GOT was out of date for " << (void*)BufferBegin
1082 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx] << "\n";
1083 ((void**)MemMgr->getGOTBase())[idx] = (void*)BufferBegin;
1087 unsigned char *FnEnd = CurBufferPtr;
1089 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, FnEnd);
1091 if (CurBufferPtr == BufferEnd) {
1092 // FIXME: Allocate more space, then try again.
1093 cerr << "JIT: Ran out of space for generated machine code!\n";
1097 BufferBegin = CurBufferPtr = 0;
1098 NumBytes += FnEnd-FnStart;
1100 // Invalidate the icache if necessary.
1101 sys::Memory::InvalidateInstructionCache(FnStart, FnEnd-FnStart);
1103 // Add it to the JIT symbol table if the host wants it.
1104 AddFunctionToSymbolTable(F.getFunction()->getNameStart(),
1105 FnStart, FnEnd-FnStart);
1107 DOUT << "JIT: Finished CodeGen of [" << (void*)FnStart
1108 << "] Function: " << F.getFunction()->getName()
1109 << ": " << (FnEnd-FnStart) << " bytes of text, "
1110 << Relocations.size() << " relocations\n";
1111 Relocations.clear();
1113 // Mark code region readable and executable if it's not so already.
1114 MemMgr->setMemoryExecutable();
1118 if (sys::hasDisassembler()) {
1119 DOUT << "JIT: Disassembled code:\n";
1120 DOUT << sys::disassembleBuffer(FnStart, FnEnd-FnStart, (uintptr_t)FnStart);
1122 DOUT << "JIT: Binary code:\n";
1124 unsigned char* q = FnStart;
1125 for (int i = 0; q < FnEnd; q += 4, ++i) {
1129 DOUT << "JIT: " << std::setw(8) << std::setfill('0')
1130 << (long)(q - FnStart) << ": ";
1132 for (int j = 3; j >= 0; --j) {
1136 DOUT << std::setw(2) << std::setfill('0') << (unsigned short)q[j];
1149 if (ExceptionHandling) {
1150 uintptr_t ActualSize = 0;
1151 SavedBufferBegin = BufferBegin;
1152 SavedBufferEnd = BufferEnd;
1153 SavedCurBufferPtr = CurBufferPtr;
1155 if (MemMgr->NeedsExactSize()) {
1156 ActualSize = DE->GetDwarfTableSizeInBytes(F, *this, FnStart, FnEnd);
1159 BufferBegin = CurBufferPtr = MemMgr->startExceptionTable(F.getFunction(),
1161 BufferEnd = BufferBegin+ActualSize;
1162 unsigned char* FrameRegister = DE->EmitDwarfTable(F, *this, FnStart, FnEnd);
1163 MemMgr->endExceptionTable(F.getFunction(), BufferBegin, CurBufferPtr,
1165 BufferBegin = SavedBufferBegin;
1166 BufferEnd = SavedBufferEnd;
1167 CurBufferPtr = SavedCurBufferPtr;
1169 TheJIT->RegisterTable(FrameRegister);
1178 /// deallocateMemForFunction - Deallocate all memory for the specified
1179 /// function body. Also drop any references the function has to stubs.
1180 void JITEmitter::deallocateMemForFunction(Function *F) {
1181 MemMgr->deallocateMemForFunction(F);
1183 // If the function did not reference any stubs, return.
1184 if (CurFnStubUses.find(F) == CurFnStubUses.end())
1187 // For each referenced stub, erase the reference to this function, and then
1188 // erase the list of referenced stubs.
1189 SmallVectorImpl<void *> &StubList = CurFnStubUses[F];
1190 for (unsigned i = 0, e = StubList.size(); i != e; ++i) {
1191 void *Stub = StubList[i];
1192 SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[Stub];
1195 // If this function was the last reference to the stub, invalidate the stub
1196 // in the JITResolver. Were there a memory manager deallocateStub routine,
1197 // we could call that at this point too.
1198 if (FnRefs.empty()) {
1199 DOUT << "\nJIT: Invalidated Stub at [" << Stub << "]\n";
1200 GlobalValue *GV = Resolver.invalidateStub(Stub);
1201 TheJIT->updateGlobalMapping(GV, 0);
1202 StubFnRefs.erase(F);
1205 CurFnStubUses.erase(F);
1209 void* JITEmitter::allocateSpace(uintptr_t Size, unsigned Alignment) {
1211 return MachineCodeEmitter::allocateSpace(Size, Alignment);
1213 // create a new memory block if there is no active one.
1214 // care must be taken so that BufferBegin is invalidated when a
1216 BufferBegin = CurBufferPtr = MemMgr->allocateSpace(Size, Alignment);
1217 BufferEnd = BufferBegin+Size;
1218 return CurBufferPtr;
1221 void JITEmitter::emitConstantPool(MachineConstantPool *MCP) {
1222 if (TheJIT->getJITInfo().hasCustomConstantPool())
1225 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
1226 if (Constants.empty()) return;
1228 MachineConstantPoolEntry CPE = Constants.back();
1229 unsigned Size = CPE.Offset;
1230 const Type *Ty = CPE.isMachineConstantPoolEntry()
1231 ? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal->getType();
1232 Size += TheJIT->getTargetData()->getTypePaddedSize(Ty);
1234 unsigned Align = 1 << MCP->getConstantPoolAlignment();
1235 ConstantPoolBase = allocateSpace(Size, Align);
1238 if (ConstantPoolBase == 0) return; // Buffer overflow.
1240 DOUT << "JIT: Emitted constant pool at [" << ConstantPoolBase
1241 << "] (size: " << Size << ", alignment: " << Align << ")\n";
1243 // Initialize the memory for all of the constant pool entries.
1244 for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
1245 void *CAddr = (char*)ConstantPoolBase+Constants[i].Offset;
1246 if (Constants[i].isMachineConstantPoolEntry()) {
1247 // FIXME: add support to lower machine constant pool values into bytes!
1248 cerr << "Initialize memory with machine specific constant pool entry"
1249 << " has not been implemented!\n";
1252 TheJIT->InitializeMemory(Constants[i].Val.ConstVal, CAddr);
1253 DOUT << "JIT: CP" << i << " at [" << CAddr << "]\n";
1257 void JITEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) {
1258 if (TheJIT->getJITInfo().hasCustomJumpTables())
1261 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1262 if (JT.empty()) return;
1264 unsigned NumEntries = 0;
1265 for (unsigned i = 0, e = JT.size(); i != e; ++i)
1266 NumEntries += JT[i].MBBs.size();
1268 unsigned EntrySize = MJTI->getEntrySize();
1270 // Just allocate space for all the jump tables now. We will fix up the actual
1271 // MBB entries in the tables after we emit the code for each block, since then
1272 // we will know the final locations of the MBBs in memory.
1274 JumpTableBase = allocateSpace(NumEntries * EntrySize, MJTI->getAlignment());
1277 void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) {
1278 if (TheJIT->getJITInfo().hasCustomJumpTables())
1281 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1282 if (JT.empty() || JumpTableBase == 0) return;
1284 if (TargetMachine::getRelocationModel() == Reloc::PIC_) {
1285 assert(MJTI->getEntrySize() == 4 && "Cross JIT'ing?");
1286 // For each jump table, place the offset from the beginning of the table
1287 // to the target address.
1288 int *SlotPtr = (int*)JumpTableBase;
1290 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1291 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1292 // Store the offset of the basic block for this jump table slot in the
1293 // memory we allocated for the jump table in 'initJumpTableInfo'
1294 uintptr_t Base = (uintptr_t)SlotPtr;
1295 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) {
1296 uintptr_t MBBAddr = getMachineBasicBlockAddress(MBBs[mi]);
1297 *SlotPtr++ = TheJIT->getJITInfo().getPICJumpTableEntry(MBBAddr, Base);
1301 assert(MJTI->getEntrySize() == sizeof(void*) && "Cross JIT'ing?");
1303 // For each jump table, map each target in the jump table to the address of
1304 // an emitted MachineBasicBlock.
1305 intptr_t *SlotPtr = (intptr_t*)JumpTableBase;
1307 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1308 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1309 // Store the address of the basic block for this jump table slot in the
1310 // memory we allocated for the jump table in 'initJumpTableInfo'
1311 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi)
1312 *SlotPtr++ = getMachineBasicBlockAddress(MBBs[mi]);
1317 void JITEmitter::startGVStub(const GlobalValue* GV, unsigned StubSize,
1318 unsigned Alignment) {
1319 SavedBufferBegin = BufferBegin;
1320 SavedBufferEnd = BufferEnd;
1321 SavedCurBufferPtr = CurBufferPtr;
1323 BufferBegin = CurBufferPtr = MemMgr->allocateStub(GV, StubSize, Alignment);
1324 BufferEnd = BufferBegin+StubSize+1;
1327 void JITEmitter::startGVStub(const GlobalValue* GV, void *Buffer,
1328 unsigned StubSize) {
1329 SavedBufferBegin = BufferBegin;
1330 SavedBufferEnd = BufferEnd;
1331 SavedCurBufferPtr = CurBufferPtr;
1333 BufferBegin = CurBufferPtr = (unsigned char *)Buffer;
1334 BufferEnd = BufferBegin+StubSize+1;
1337 void *JITEmitter::finishGVStub(const GlobalValue* GV) {
1338 NumBytes += getCurrentPCOffset();
1339 std::swap(SavedBufferBegin, BufferBegin);
1340 BufferEnd = SavedBufferEnd;
1341 CurBufferPtr = SavedCurBufferPtr;
1342 return SavedBufferBegin;
1345 // getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry
1346 // in the constant pool that was last emitted with the 'emitConstantPool'
1349 uintptr_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) const {
1350 assert(ConstantNum < ConstantPool->getConstants().size() &&
1351 "Invalid ConstantPoolIndex!");
1352 return (uintptr_t)ConstantPoolBase +
1353 ConstantPool->getConstants()[ConstantNum].Offset;
1356 // getJumpTableEntryAddress - Return the address of the JumpTable with index
1357 // 'Index' in the jumpp table that was last initialized with 'initJumpTableInfo'
1359 uintptr_t JITEmitter::getJumpTableEntryAddress(unsigned Index) const {
1360 const std::vector<MachineJumpTableEntry> &JT = JumpTable->getJumpTables();
1361 assert(Index < JT.size() && "Invalid jump table index!");
1363 unsigned Offset = 0;
1364 unsigned EntrySize = JumpTable->getEntrySize();
1366 for (unsigned i = 0; i < Index; ++i)
1367 Offset += JT[i].MBBs.size();
1369 Offset *= EntrySize;
1371 return (uintptr_t)((char *)JumpTableBase + Offset);
1374 //===----------------------------------------------------------------------===//
1375 // Public interface to this file
1376 //===----------------------------------------------------------------------===//
1378 MachineCodeEmitter *JIT::createEmitter(JIT &jit, JITMemoryManager *JMM) {
1379 return new JITEmitter(jit, JMM);
1382 // getPointerToNamedFunction - This function is used as a global wrapper to
1383 // JIT::getPointerToNamedFunction for the purpose of resolving symbols when
1384 // bugpoint is debugging the JIT. In that scenario, we are loading an .so and
1385 // need to resolve function(s) that are being mis-codegenerated, so we need to
1386 // resolve their addresses at runtime, and this is the way to do it.
1388 void *getPointerToNamedFunction(const char *Name) {
1389 if (Function *F = TheJIT->FindFunctionNamed(Name))
1390 return TheJIT->getPointerToFunction(F);
1391 return TheJIT->getPointerToNamedFunction(Name);
1395 // getPointerToFunctionOrStub - If the specified function has been
1396 // code-gen'd, return a pointer to the function. If not, compile it, or use
1397 // a stub to implement lazy compilation if available.
1399 void *JIT::getPointerToFunctionOrStub(Function *F) {
1400 // If we have already code generated the function, just return the address.
1401 if (void *Addr = getPointerToGlobalIfAvailable(F))
1404 // Get a stub if the target supports it.
1405 assert(isa<JITEmitter>(MCE) && "Unexpected MCE?");
1406 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1407 return JE->getJITResolver().getFunctionStub(F);
1410 void JIT::updateFunctionStub(Function *F) {
1411 // Get the empty stub we generated earlier.
1412 assert(isa<JITEmitter>(MCE) && "Unexpected MCE?");
1413 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1414 void *Stub = JE->getJITResolver().getFunctionStub(F);
1416 // Tell the target jit info to rewrite the stub at the specified address,
1417 // rather than creating a new one.
1418 void *Addr = getPointerToGlobalIfAvailable(F);
1419 getJITInfo().emitFunctionStubAtAddr(F, Addr, Stub, *getCodeEmitter());
1422 /// updateDlsymStubTable - Emit the data necessary to relocate the stubs
1423 /// that were emitted during code generation.
1425 void JIT::updateDlsymStubTable() {
1426 assert(isa<JITEmitter>(MCE) && "Unexpected MCE?");
1427 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1429 SmallVector<GlobalValue*, 8> GVs;
1430 SmallVector<void*, 8> Ptrs;
1432 JE->getJITResolver().getRelocatableGVs(GVs, Ptrs);
1434 // If there are no relocatable stubs, return.
1438 // If there are no new relocatable stubs, return.
1439 void *CurTable = JE->getMemMgr()->getDlsymTable();
1440 if (CurTable && (*(unsigned *)CurTable == GVs.size()))
1443 // Calculate the size of the stub info
1444 unsigned offset = 4 + 4 * GVs.size() + sizeof(intptr_t) * GVs.size();
1446 SmallVector<unsigned, 8> Offsets;
1447 for (unsigned i = 0; i != GVs.size(); ++i) {
1448 Offsets.push_back(offset);
1449 offset += GVs[i]->getName().length() + 1;
1452 // Allocate space for the new "stub", which contains the dlsym table.
1453 JE->startGVStub(0, offset, 4);
1455 // Emit the number of records
1456 MCE->emitInt32(GVs.size());
1458 // Emit the string offsets
1459 for (unsigned i = 0; i != GVs.size(); ++i)
1460 MCE->emitInt32(Offsets[i]);
1462 // Emit the pointers. Verify that they are at least 2-byte aligned, and set
1463 // the low bit to 0 == GV, 1 == Function, so that the client code doing the
1464 // relocation can write the relocated pointer at the appropriate place in
1466 for (unsigned i = 0; i != GVs.size(); ++i) {
1467 intptr_t Ptr = (intptr_t)Ptrs[i];
1468 assert((Ptr & 1) == 0 && "Stub pointers must be at least 2-byte aligned!");
1470 if (isa<Function>(GVs[i]))
1473 if (sizeof(void *) == 8)
1474 MCE->emitInt64(Ptr);
1476 MCE->emitInt32(Ptr);
1479 // Emit the strings.
1480 for (unsigned i = 0; i != GVs.size(); ++i)
1481 MCE->emitString(GVs[i]->getName());
1483 // Tell the JIT memory manager where it is. The JIT Memory Manager will
1484 // deallocate space for the old one, if one existed.
1485 JE->getMemMgr()->SetDlsymTable(JE->finishGVStub(0));
1488 /// freeMachineCodeForFunction - release machine code memory for given Function.
1490 void JIT::freeMachineCodeForFunction(Function *F) {
1492 // Delete translation for this from the ExecutionEngine, so it will get
1493 // retranslated next time it is used.
1494 void *OldPtr = updateGlobalMapping(F, 0);
1497 RemoveFunctionFromSymbolTable(OldPtr);
1499 // Free the actual memory for the function body and related stuff.
1500 assert(isa<JITEmitter>(MCE) && "Unexpected MCE?");
1501 cast<JITEmitter>(MCE)->deallocateMemForFunction(F);