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/Statistic.h"
46 STATISTIC(NumBytes, "Number of bytes of machine code compiled");
47 STATISTIC(NumRelos, "Number of relocations applied");
48 static JIT *TheJIT = 0;
51 //===----------------------------------------------------------------------===//
52 // JIT lazy compilation code.
55 class JITResolverState {
57 /// FunctionToStubMap - Keep track of the stub created for a particular
58 /// function so that we can reuse them if necessary.
59 std::map<Function*, void*> FunctionToStubMap;
61 /// StubToFunctionMap - Keep track of the function that each stub
63 std::map<void*, Function*> StubToFunctionMap;
65 /// GlobalToNonLazyPtrMap - Keep track of the lazy pointer created for a
66 /// particular GlobalVariable so that we can reuse them if necessary.
67 std::map<GlobalValue*, void*> GlobalToNonLazyPtrMap;
70 std::map<Function*, void*>& getFunctionToStubMap(const MutexGuard& locked) {
71 assert(locked.holds(TheJIT->lock));
72 return FunctionToStubMap;
75 std::map<void*, Function*>& getStubToFunctionMap(const MutexGuard& locked) {
76 assert(locked.holds(TheJIT->lock));
77 return StubToFunctionMap;
80 std::map<GlobalValue*, void*>&
81 getGlobalToNonLazyPtrMap(const MutexGuard& locked) {
82 assert(locked.holds(TheJIT->lock));
83 return GlobalToNonLazyPtrMap;
87 /// JITResolver - Keep track of, and resolve, call sites for functions that
88 /// have not yet been compiled.
90 /// LazyResolverFn - The target lazy resolver function that we actually
91 /// rewrite instructions to use.
92 TargetJITInfo::LazyResolverFn LazyResolverFn;
94 JITResolverState state;
96 /// ExternalFnToStubMap - This is the equivalent of FunctionToStubMap for
97 /// external functions.
98 std::map<void*, void*> ExternalFnToStubMap;
100 //map addresses to indexes in the GOT
101 std::map<void*, unsigned> revGOTMap;
102 unsigned nextGOTIndex;
104 static JITResolver *TheJITResolver;
106 explicit JITResolver(JIT &jit) : nextGOTIndex(0) {
109 LazyResolverFn = jit.getJITInfo().getLazyResolverFunction(JITCompilerFn);
110 assert(TheJITResolver == 0 && "Multiple JIT resolvers?");
111 TheJITResolver = this;
118 /// getFunctionStub - This returns a pointer to a function stub, creating
119 /// one on demand as needed.
120 void *getFunctionStub(Function *F);
122 /// getExternalFunctionStub - Return a stub for the function at the
123 /// specified address, created lazily on demand.
124 void *getExternalFunctionStub(void *FnAddr);
126 /// getGlobalValueNonLazyPtr - Return a non-lazy pointer containing the
127 /// specified GV address.
128 void *getGlobalValueNonLazyPtr(GlobalValue *V, void *GVAddress);
130 /// AddCallbackAtLocation - If the target is capable of rewriting an
131 /// instruction without the use of a stub, record the location of the use so
132 /// we know which function is being used at the location.
133 void *AddCallbackAtLocation(Function *F, void *Location) {
134 MutexGuard locked(TheJIT->lock);
135 /// Get the target-specific JIT resolver function.
136 state.getStubToFunctionMap(locked)[Location] = F;
137 return (void*)(intptr_t)LazyResolverFn;
140 /// getGOTIndexForAddress - Return a new or existing index in the GOT for
141 /// an address. This function only manages slots, it does not manage the
142 /// contents of the slots or the memory associated with the GOT.
143 unsigned getGOTIndexForAddr(void *addr);
145 /// JITCompilerFn - This function is called to resolve a stub to a compiled
146 /// address. If the LLVM Function corresponding to the stub has not yet
147 /// been compiled, this function compiles it first.
148 static void *JITCompilerFn(void *Stub);
152 JITResolver *JITResolver::TheJITResolver = 0;
154 /// getFunctionStub - This returns a pointer to a function stub, creating
155 /// one on demand as needed.
156 void *JITResolver::getFunctionStub(Function *F) {
157 MutexGuard locked(TheJIT->lock);
159 // If we already have a stub for this function, recycle it.
160 void *&Stub = state.getFunctionToStubMap(locked)[F];
161 if (Stub) return Stub;
163 // Call the lazy resolver function unless we already KNOW it is an external
164 // function, in which case we just skip the lazy resolution step.
165 void *Actual = (void*)(intptr_t)LazyResolverFn;
166 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode())
167 Actual = TheJIT->getPointerToFunction(F);
169 // Otherwise, codegen a new stub. For now, the stub will call the lazy
170 // resolver function.
171 Stub = TheJIT->getJITInfo().emitFunctionStub(F, Actual,
172 *TheJIT->getCodeEmitter());
174 if (Actual != (void*)(intptr_t)LazyResolverFn) {
175 // If we are getting the stub for an external function, we really want the
176 // address of the stub in the GlobalAddressMap for the JIT, not the address
177 // of the external function.
178 TheJIT->updateGlobalMapping(F, Stub);
181 DOUT << "JIT: Stub emitted at [" << Stub << "] for function '"
182 << F->getName() << "'\n";
184 // Finally, keep track of the stub-to-Function mapping so that the
185 // JITCompilerFn knows which function to compile!
186 state.getStubToFunctionMap(locked)[Stub] = F;
190 /// getGlobalValueNonLazyPtr - Return a lazy pointer containing the specified
192 void *JITResolver::getGlobalValueNonLazyPtr(GlobalValue *GV, void *GVAddress) {
193 MutexGuard locked(TheJIT->lock);
195 // If we already have a stub for this global variable, recycle it.
196 void *&NonLazyPtr = state.getGlobalToNonLazyPtrMap(locked)[GV];
197 if (NonLazyPtr) return NonLazyPtr;
199 // Otherwise, codegen a new lazy pointer.
200 NonLazyPtr = TheJIT->getJITInfo().emitGlobalValueNonLazyPtr(GV, GVAddress,
201 *TheJIT->getCodeEmitter());
203 DOUT << "JIT: Stub emitted at [" << NonLazyPtr << "] for GV '"
204 << GV->getName() << "'\n";
209 /// getExternalFunctionStub - Return a stub for the function at the
210 /// specified address, created lazily on demand.
211 void *JITResolver::getExternalFunctionStub(void *FnAddr) {
212 // If we already have a stub for this function, recycle it.
213 void *&Stub = ExternalFnToStubMap[FnAddr];
214 if (Stub) return Stub;
216 Stub = TheJIT->getJITInfo().emitFunctionStub(0, FnAddr,
217 *TheJIT->getCodeEmitter());
219 DOUT << "JIT: Stub emitted at [" << Stub
220 << "] for external function at '" << FnAddr << "'\n";
224 unsigned JITResolver::getGOTIndexForAddr(void* addr) {
225 unsigned idx = revGOTMap[addr];
227 idx = ++nextGOTIndex;
228 revGOTMap[addr] = idx;
229 DOUT << "JIT: Adding GOT entry " << idx << " for addr " << addr << "\n";
234 /// JITCompilerFn - This function is called when a lazy compilation stub has
235 /// been entered. It looks up which function this stub corresponds to, compiles
236 /// it if necessary, then returns the resultant function pointer.
237 void *JITResolver::JITCompilerFn(void *Stub) {
238 JITResolver &JR = *TheJITResolver;
244 // Only lock for getting the Function. The call getPointerToFunction made
245 // in this function might trigger function materializing, which requires
246 // JIT lock to be unlocked.
247 MutexGuard locked(TheJIT->lock);
249 // The address given to us for the stub may not be exactly right, it might be
250 // a little bit after the stub. As such, use upper_bound to find it.
251 std::map<void*, Function*>::iterator I =
252 JR.state.getStubToFunctionMap(locked).upper_bound(Stub);
253 assert(I != JR.state.getStubToFunctionMap(locked).begin() &&
254 "This is not a known stub!");
256 ActualPtr = I->first;
259 // If we have already code generated the function, just return the address.
260 void *Result = TheJIT->getPointerToGlobalIfAvailable(F);
263 // Otherwise we don't have it, do lazy compilation now.
265 // If lazy compilation is disabled, emit a useful error message and abort.
266 if (TheJIT->isLazyCompilationDisabled()) {
267 cerr << "LLVM JIT requested to do lazy compilation of function '"
268 << F->getName() << "' when lazy compiles are disabled!\n";
272 // We might like to remove the stub from the StubToFunction map.
273 // We can't do that! Multiple threads could be stuck, waiting to acquire the
274 // lock above. As soon as the 1st function finishes compiling the function,
275 // the next one will be released, and needs to be able to find the function
277 //JR.state.getStubToFunctionMap(locked).erase(I);
279 DOUT << "JIT: Lazily resolving function '" << F->getName()
280 << "' In stub ptr = " << Stub << " actual ptr = "
281 << ActualPtr << "\n";
283 Result = TheJIT->getPointerToFunction(F);
286 // Reacquire the lock to erase the stub in the map.
287 MutexGuard locked(TheJIT->lock);
289 // We don't need to reuse this stub in the future, as F is now compiled.
290 JR.state.getFunctionToStubMap(locked).erase(F);
292 // FIXME: We could rewrite all references to this stub if we knew them.
294 // What we will do is set the compiled function address to map to the
295 // same GOT entry as the stub so that later clients may update the GOT
296 // if they see it still using the stub address.
297 // Note: this is done so the Resolver doesn't have to manage GOT memory
298 // Do this without allocating map space if the target isn't using a GOT
299 if(JR.revGOTMap.find(Stub) != JR.revGOTMap.end())
300 JR.revGOTMap[Result] = JR.revGOTMap[Stub];
305 //===----------------------------------------------------------------------===//
306 // Function Index Support
308 // On MacOS we generate an index of currently JIT'd functions so that
309 // performance tools can determine a symbol name and accurate code range for a
310 // PC value. Because performance tools are generally asynchronous, the code
311 // below is written with the hope that it could be interrupted at any time and
312 // have useful answers. However, we don't go crazy with atomic operations, we
313 // just do a "reasonable effort".
315 #define ENABLE_JIT_SYMBOL_TABLE 0
318 /// JitSymbolEntry - Each function that is JIT compiled results in one of these
319 /// being added to an array of symbols. This indicates the name of the function
320 /// as well as the address range it occupies. This allows the client to map
321 /// from a PC value to the name of the function.
322 struct JitSymbolEntry {
323 const char *FnName; // FnName - a strdup'd string.
329 struct JitSymbolTable {
330 /// NextPtr - This forms a linked list of JitSymbolTable entries. This
331 /// pointer is not used right now, but might be used in the future. Consider
332 /// it reserved for future use.
333 JitSymbolTable *NextPtr;
335 /// Symbols - This is an array of JitSymbolEntry entries. Only the first
336 /// 'NumSymbols' symbols are valid.
337 JitSymbolEntry *Symbols;
339 /// NumSymbols - This indicates the number entries in the Symbols array that
343 /// NumAllocated - This indicates the amount of space we have in the Symbols
344 /// array. This is a private field that should not be read by external tools.
345 unsigned NumAllocated;
348 #if ENABLE_JIT_SYMBOL_TABLE
349 JitSymbolTable *__jitSymbolTable;
352 static void AddFunctionToSymbolTable(const char *FnName,
353 void *FnStart, intptr_t FnSize) {
354 assert(FnName != 0 && FnStart != 0 && "Bad symbol to add");
355 JitSymbolTable **SymTabPtrPtr = 0;
356 #if !ENABLE_JIT_SYMBOL_TABLE
359 SymTabPtrPtr = &__jitSymbolTable;
362 // If this is the first entry in the symbol table, add the JitSymbolTable
364 if (*SymTabPtrPtr == 0) {
365 JitSymbolTable *New = new JitSymbolTable();
369 New->NumAllocated = 0;
373 JitSymbolTable *SymTabPtr = *SymTabPtrPtr;
375 // If we have space in the table, reallocate the table.
376 if (SymTabPtr->NumSymbols >= SymTabPtr->NumAllocated) {
377 // If we don't have space, reallocate the table.
378 unsigned NewSize = std::max(64U, SymTabPtr->NumAllocated*2);
379 JitSymbolEntry *NewSymbols = new JitSymbolEntry[NewSize];
380 JitSymbolEntry *OldSymbols = SymTabPtr->Symbols;
382 // Copy the old entries over.
383 memcpy(NewSymbols, OldSymbols,
384 SymTabPtr->NumSymbols*sizeof(OldSymbols[0]));
386 // Swap the new symbols in, delete the old ones.
387 SymTabPtr->Symbols = NewSymbols;
388 SymTabPtr->NumAllocated = NewSize;
389 delete [] OldSymbols;
392 // Otherwise, we have enough space, just tack it onto the end of the array.
393 JitSymbolEntry &Entry = SymTabPtr->Symbols[SymTabPtr->NumSymbols];
394 Entry.FnName = strdup(FnName);
395 Entry.FnStart = FnStart;
396 Entry.FnSize = FnSize;
397 ++SymTabPtr->NumSymbols;
400 static void RemoveFunctionFromSymbolTable(void *FnStart) {
401 assert(FnStart && "Invalid function pointer");
402 JitSymbolTable **SymTabPtrPtr = 0;
403 #if !ENABLE_JIT_SYMBOL_TABLE
406 SymTabPtrPtr = &__jitSymbolTable;
409 JitSymbolTable *SymTabPtr = *SymTabPtrPtr;
410 JitSymbolEntry *Symbols = SymTabPtr->Symbols;
412 // Scan the table to find its index. The table is not sorted, so do a linear
415 for (Index = 0; Symbols[Index].FnStart != FnStart; ++Index)
416 assert(Index != SymTabPtr->NumSymbols && "Didn't find function!");
418 // Once we have an index, we know to nuke this entry, overwrite it with the
419 // entry at the end of the array, making the last entry redundant.
420 const char *OldName = Symbols[Index].FnName;
421 Symbols[Index] = Symbols[SymTabPtr->NumSymbols-1];
422 free((void*)OldName);
424 // Drop the number of symbols in the table.
425 --SymTabPtr->NumSymbols;
427 // Finally, if we deleted the final symbol, deallocate the table itself.
428 if (SymTabPtr->NumSymbols != 0)
436 //===----------------------------------------------------------------------===//
440 /// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is
441 /// used to output functions to memory for execution.
442 class JITEmitter : public MachineCodeEmitter {
443 JITMemoryManager *MemMgr;
445 // When outputting a function stub in the context of some other function, we
446 // save BufferBegin/BufferEnd/CurBufferPtr here.
447 unsigned char *SavedBufferBegin, *SavedBufferEnd, *SavedCurBufferPtr;
449 /// Relocations - These are the relocations that the function needs, as
451 std::vector<MachineRelocation> Relocations;
453 /// MBBLocations - This vector is a mapping from MBB ID's to their address.
454 /// It is filled in by the StartMachineBasicBlock callback and queried by
455 /// the getMachineBasicBlockAddress callback.
456 std::vector<intptr_t> MBBLocations;
458 /// ConstantPool - The constant pool for the current function.
460 MachineConstantPool *ConstantPool;
462 /// ConstantPoolBase - A pointer to the first entry in the constant pool.
464 void *ConstantPoolBase;
466 /// JumpTable - The jump tables for the current function.
468 MachineJumpTableInfo *JumpTable;
470 /// JumpTableBase - A pointer to the first entry in the jump table.
474 /// Resolver - This contains info about the currently resolved functions.
475 JITResolver Resolver;
477 /// DE - The dwarf emitter for the jit.
480 /// LabelLocations - This vector is a mapping from Label ID's to their
482 std::vector<intptr_t> LabelLocations;
484 /// MMI - Machine module info for exception informations
485 MachineModuleInfo* MMI;
487 // GVSet - a set to keep track of which globals have been seen
488 SmallPtrSet<const GlobalVariable*, 8> GVSet;
491 JITEmitter(JIT &jit, JITMemoryManager *JMM) : Resolver(jit) {
492 MemMgr = JMM ? JMM : JITMemoryManager::CreateDefaultMemManager();
493 if (jit.getJITInfo().needsGOT()) {
494 MemMgr->AllocateGOT();
495 DOUT << "JIT is managing a GOT\n";
498 if (ExceptionHandling) DE = new JITDwarfEmitter(jit);
502 if (ExceptionHandling) delete DE;
505 /// classof - Methods for support type inquiry through isa, cast, and
508 static inline bool classof(const JITEmitter*) { return true; }
509 static inline bool classof(const MachineCodeEmitter*) { return true; }
511 JITResolver &getJITResolver() { return Resolver; }
513 virtual void startFunction(MachineFunction &F);
514 virtual bool finishFunction(MachineFunction &F);
516 void emitConstantPool(MachineConstantPool *MCP);
517 void initJumpTableInfo(MachineJumpTableInfo *MJTI);
518 void emitJumpTableInfo(MachineJumpTableInfo *MJTI);
520 virtual void startFunctionStub(const GlobalValue* F, unsigned StubSize,
521 unsigned Alignment = 1);
522 virtual void* finishFunctionStub(const GlobalValue *F);
524 /// allocateSpace - Reserves space in the current block if any, or
525 /// allocate a new one of the given size.
526 virtual void *allocateSpace(intptr_t Size, unsigned Alignment);
528 virtual void addRelocation(const MachineRelocation &MR) {
529 Relocations.push_back(MR);
532 virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {
533 if (MBBLocations.size() <= (unsigned)MBB->getNumber())
534 MBBLocations.resize((MBB->getNumber()+1)*2);
535 MBBLocations[MBB->getNumber()] = getCurrentPCValue();
538 virtual intptr_t getConstantPoolEntryAddress(unsigned Entry) const;
539 virtual intptr_t getJumpTableEntryAddress(unsigned Entry) const;
541 virtual intptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const {
542 assert(MBBLocations.size() > (unsigned)MBB->getNumber() &&
543 MBBLocations[MBB->getNumber()] && "MBB not emitted!");
544 return MBBLocations[MBB->getNumber()];
547 /// deallocateMemForFunction - Deallocate all memory for the specified
549 void deallocateMemForFunction(Function *F) {
550 MemMgr->deallocateMemForFunction(F);
553 virtual void emitLabel(uint64_t LabelID) {
554 if (LabelLocations.size() <= LabelID)
555 LabelLocations.resize((LabelID+1)*2);
556 LabelLocations[LabelID] = getCurrentPCValue();
559 virtual intptr_t getLabelAddress(uint64_t LabelID) const {
560 assert(LabelLocations.size() > (unsigned)LabelID &&
561 LabelLocations[LabelID] && "Label not emitted!");
562 return LabelLocations[LabelID];
565 virtual void setModuleInfo(MachineModuleInfo* Info) {
567 if (ExceptionHandling) DE->setModuleInfo(Info);
570 void setMemoryExecutable(void) {
571 MemMgr->setMemoryExecutable();
575 void *getPointerToGlobal(GlobalValue *GV, void *Reference, bool NoNeedStub);
576 void *getPointerToGVNonLazyPtr(GlobalValue *V, void *Reference,
578 unsigned addSizeOfGlobal(const GlobalVariable *GV, unsigned Size);
579 unsigned addSizeOfGlobalsInConstantVal(const Constant *C, unsigned Size);
580 unsigned addSizeOfGlobalsInInitializer(const Constant *Init, unsigned Size);
581 unsigned GetSizeOfGlobalsInBytes(MachineFunction &MF);
585 void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference,
586 bool DoesntNeedStub) {
587 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) {
588 /// FIXME: If we straightened things out, this could actually emit the
589 /// global immediately instead of queuing it for codegen later!
590 return TheJIT->getOrEmitGlobalVariable(GV);
592 if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
593 return TheJIT->getPointerToGlobal(GA->resolveAliasedGlobal(false));
595 // If we have already compiled the function, return a pointer to its body.
596 Function *F = cast<Function>(V);
597 void *ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F);
598 if (ResultPtr) return ResultPtr;
600 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode()) {
601 // If this is an external function pointer, we can force the JIT to
602 // 'compile' it, which really just adds it to the map.
604 return TheJIT->getPointerToFunction(F);
606 return Resolver.getFunctionStub(F);
609 // Okay, the function has not been compiled yet, if the target callback
610 // mechanism is capable of rewriting the instruction directly, prefer to do
611 // that instead of emitting a stub.
613 return Resolver.AddCallbackAtLocation(F, Reference);
615 // Otherwise, we have to emit a lazy resolving stub.
616 return Resolver.getFunctionStub(F);
619 void *JITEmitter::getPointerToGVNonLazyPtr(GlobalValue *V, void *Reference,
620 bool DoesntNeedStub) {
621 // Make sure GV is emitted first.
622 // FIXME: For now, if the GV is an external function we force the JIT to
623 // compile it so the non-lazy pointer will contain the fully resolved address.
624 void *GVAddress = getPointerToGlobal(V, Reference, true);
625 return Resolver.getGlobalValueNonLazyPtr(V, GVAddress);
628 static unsigned GetConstantPoolSizeInBytes(MachineConstantPool *MCP) {
629 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
630 if (Constants.empty()) return 0;
632 MachineConstantPoolEntry CPE = Constants.back();
633 unsigned Size = CPE.Offset;
634 const Type *Ty = CPE.isMachineConstantPoolEntry()
635 ? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal->getType();
636 Size += TheJIT->getTargetData()->getABITypeSize(Ty);
640 static unsigned GetJumpTableSizeInBytes(MachineJumpTableInfo *MJTI) {
641 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
642 if (JT.empty()) return 0;
644 unsigned NumEntries = 0;
645 for (unsigned i = 0, e = JT.size(); i != e; ++i)
646 NumEntries += JT[i].MBBs.size();
648 unsigned EntrySize = MJTI->getEntrySize();
650 return NumEntries * EntrySize;
653 static uintptr_t RoundUpToAlign(uintptr_t Size, unsigned Alignment) {
654 if (Alignment == 0) Alignment = 1;
655 // Since we do not know where the buffer will be allocated, be pessimistic.
656 return Size + Alignment;
659 /// addSizeOfGlobal - add the size of the global (plus any alignment padding)
660 /// into the running total Size.
662 unsigned JITEmitter::addSizeOfGlobal(const GlobalVariable *GV, unsigned Size) {
663 const Type *ElTy = GV->getType()->getElementType();
664 size_t GVSize = (size_t)TheJIT->getTargetData()->getABITypeSize(ElTy);
666 (size_t)TheJIT->getTargetData()->getPreferredAlignment(GV);
667 DOUT << "JIT: Adding in size " << GVSize << " alignment " << GVAlign;
669 // Assume code section ends with worst possible alignment, so first
670 // variable needs maximal padding.
673 Size = ((Size+GVAlign-1)/GVAlign)*GVAlign;
678 /// addSizeOfGlobalsInConstantVal - find any globals that we haven't seen yet
679 /// but are referenced from the constant; put them in GVSet and add their
680 /// size into the running total Size.
682 unsigned JITEmitter::addSizeOfGlobalsInConstantVal(const Constant *C,
684 // If its undefined, return the garbage.
685 if (isa<UndefValue>(C))
688 // If the value is a ConstantExpr
689 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
690 Constant *Op0 = CE->getOperand(0);
691 switch (CE->getOpcode()) {
692 case Instruction::GetElementPtr:
693 case Instruction::Trunc:
694 case Instruction::ZExt:
695 case Instruction::SExt:
696 case Instruction::FPTrunc:
697 case Instruction::FPExt:
698 case Instruction::UIToFP:
699 case Instruction::SIToFP:
700 case Instruction::FPToUI:
701 case Instruction::FPToSI:
702 case Instruction::PtrToInt:
703 case Instruction::IntToPtr:
704 case Instruction::BitCast: {
705 Size = addSizeOfGlobalsInConstantVal(Op0, Size);
708 case Instruction::Add:
709 case Instruction::Sub:
710 case Instruction::Mul:
711 case Instruction::UDiv:
712 case Instruction::SDiv:
713 case Instruction::URem:
714 case Instruction::SRem:
715 case Instruction::And:
716 case Instruction::Or:
717 case Instruction::Xor: {
718 Size = addSizeOfGlobalsInConstantVal(Op0, Size);
719 Size = addSizeOfGlobalsInConstantVal(CE->getOperand(1), Size);
723 cerr << "ConstantExpr not handled: " << *CE << "\n";
729 if (C->getType()->getTypeID() == Type::PointerTyID)
730 if (const GlobalVariable* GV = dyn_cast<GlobalVariable>(C))
731 if (GVSet.insert(GV))
732 Size = addSizeOfGlobal(GV, Size);
737 /// addSizeOfGLobalsInInitializer - handle any globals that we haven't seen yet
738 /// but are referenced from the given initializer.
740 unsigned JITEmitter::addSizeOfGlobalsInInitializer(const Constant *Init,
742 if (!isa<UndefValue>(Init) &&
743 !isa<ConstantVector>(Init) &&
744 !isa<ConstantAggregateZero>(Init) &&
745 !isa<ConstantArray>(Init) &&
746 !isa<ConstantStruct>(Init) &&
747 Init->getType()->isFirstClassType())
748 Size = addSizeOfGlobalsInConstantVal(Init, Size);
752 /// GetSizeOfGlobalsInBytes - walk the code for the function, looking for
753 /// globals; then walk the initializers of those globals looking for more.
754 /// If their size has not been considered yet, add it into the running total
757 unsigned JITEmitter::GetSizeOfGlobalsInBytes(MachineFunction &MF) {
761 for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
763 for (MachineBasicBlock::const_iterator I = MBB->begin(), E = MBB->end();
765 const TargetInstrDesc &Desc = I->getDesc();
766 const MachineInstr &MI = *I;
767 unsigned NumOps = Desc.getNumOperands();
768 for (unsigned CurOp = 0; CurOp < NumOps; CurOp++) {
769 const MachineOperand &MO = MI.getOperand(CurOp);
771 GlobalValue* V = MO.getGlobal();
772 const GlobalVariable *GV = dyn_cast<const GlobalVariable>(V);
775 // If seen in previous function, it will have an entry here.
776 if (TheJIT->getPointerToGlobalIfAvailable(GV))
778 // If seen earlier in this function, it will have an entry here.
779 // FIXME: it should be possible to combine these tables, by
780 // assuming the addresses of the new globals in this module
781 // start at 0 (or something) and adjusting them after codegen
782 // complete. Another possibility is to grab a marker bit in GV.
783 if (GVSet.insert(GV))
784 // A variable as yet unseen. Add in its size.
785 Size = addSizeOfGlobal(GV, Size);
790 DOUT << "JIT: About to look through initializers\n";
791 // Look for more globals that are referenced only from initializers.
792 // GVSet.end is computed each time because the set can grow as we go.
793 for (SmallPtrSet<const GlobalVariable *, 8>::iterator I = GVSet.begin();
794 I != GVSet.end(); I++) {
795 const GlobalVariable* GV = *I;
796 if (GV->hasInitializer())
797 Size = addSizeOfGlobalsInInitializer(GV->getInitializer(), Size);
803 void JITEmitter::startFunction(MachineFunction &F) {
804 DOUT << "JIT: Starting CodeGen of Function "
805 << F.getFunction()->getName() << "\n";
807 uintptr_t ActualSize = 0;
808 // Set the memory writable, if it's not already
809 MemMgr->setMemoryWritable();
810 if (MemMgr->NeedsExactSize()) {
811 DOUT << "JIT: ExactSize\n";
812 const TargetInstrInfo* TII = F.getTarget().getInstrInfo();
813 MachineJumpTableInfo *MJTI = F.getJumpTableInfo();
814 MachineConstantPool *MCP = F.getConstantPool();
816 // Ensure the constant pool/jump table info is at least 4-byte aligned.
817 ActualSize = RoundUpToAlign(ActualSize, 16);
819 // Add the alignment of the constant pool
820 ActualSize = RoundUpToAlign(ActualSize,
821 1 << MCP->getConstantPoolAlignment());
823 // Add the constant pool size
824 ActualSize += GetConstantPoolSizeInBytes(MCP);
826 // Add the aligment of the jump table info
827 ActualSize = RoundUpToAlign(ActualSize, MJTI->getAlignment());
829 // Add the jump table size
830 ActualSize += GetJumpTableSizeInBytes(MJTI);
832 // Add the alignment for the function
833 ActualSize = RoundUpToAlign(ActualSize,
834 std::max(F.getFunction()->getAlignment(), 8U));
836 // Add the function size
837 ActualSize += TII->GetFunctionSizeInBytes(F);
839 DOUT << "JIT: ActualSize before globals " << ActualSize << "\n";
840 // Add the size of the globals that will be allocated after this function.
841 // These are all the ones referenced from this function that were not
842 // previously allocated.
843 ActualSize += GetSizeOfGlobalsInBytes(F);
844 DOUT << "JIT: ActualSize after globals " << ActualSize << "\n";
847 BufferBegin = CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(),
849 BufferEnd = BufferBegin+ActualSize;
851 // Ensure the constant pool/jump table info is at least 4-byte aligned.
854 emitConstantPool(F.getConstantPool());
855 initJumpTableInfo(F.getJumpTableInfo());
857 // About to start emitting the machine code for the function.
858 emitAlignment(std::max(F.getFunction()->getAlignment(), 8U));
859 TheJIT->updateGlobalMapping(F.getFunction(), CurBufferPtr);
861 MBBLocations.clear();
864 bool JITEmitter::finishFunction(MachineFunction &F) {
865 if (CurBufferPtr == BufferEnd) {
866 // FIXME: Allocate more space, then try again.
867 cerr << "JIT: Ran out of space for generated machine code!\n";
871 emitJumpTableInfo(F.getJumpTableInfo());
873 // FnStart is the start of the text, not the start of the constant pool and
874 // other per-function data.
875 unsigned char *FnStart =
876 (unsigned char *)TheJIT->getPointerToGlobalIfAvailable(F.getFunction());
878 if (!Relocations.empty()) {
879 NumRelos += Relocations.size();
881 // Resolve the relocations to concrete pointers.
882 for (unsigned i = 0, e = Relocations.size(); i != e; ++i) {
883 MachineRelocation &MR = Relocations[i];
885 if (!MR.letTargetResolve()) {
887 ResultPtr = TheJIT->getPointerToNamedFunction(MR.getString());
889 // If the target REALLY wants a stub for this function, emit it now.
890 if (!MR.doesntNeedStub())
891 ResultPtr = Resolver.getExternalFunctionStub(ResultPtr);
892 } else if (MR.isGlobalValue()) {
893 ResultPtr = getPointerToGlobal(MR.getGlobalValue(),
894 BufferBegin+MR.getMachineCodeOffset(),
895 MR.doesntNeedStub());
896 } else if (MR.isGlobalValueNonLazyPtr()) {
897 ResultPtr = getPointerToGVNonLazyPtr(MR.getGlobalValue(),
898 BufferBegin+MR.getMachineCodeOffset(),
899 MR.doesntNeedStub());
900 } else if (MR.isBasicBlock()) {
901 ResultPtr = (void*)getMachineBasicBlockAddress(MR.getBasicBlock());
902 } else if (MR.isConstantPoolIndex()) {
903 ResultPtr = (void*)getConstantPoolEntryAddress(MR.getConstantPoolIndex());
905 assert(MR.isJumpTableIndex());
906 ResultPtr=(void*)getJumpTableEntryAddress(MR.getJumpTableIndex());
909 MR.setResultPointer(ResultPtr);
912 // if we are managing the GOT and the relocation wants an index,
914 if (MR.isGOTRelative() && MemMgr->isManagingGOT()) {
915 unsigned idx = Resolver.getGOTIndexForAddr(ResultPtr);
917 if (((void**)MemMgr->getGOTBase())[idx] != ResultPtr) {
918 DOUT << "JIT: GOT was out of date for " << ResultPtr
919 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
921 ((void**)MemMgr->getGOTBase())[idx] = ResultPtr;
926 TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0],
927 Relocations.size(), MemMgr->getGOTBase());
930 // Update the GOT entry for F to point to the new code.
931 if (MemMgr->isManagingGOT()) {
932 unsigned idx = Resolver.getGOTIndexForAddr((void*)BufferBegin);
933 if (((void**)MemMgr->getGOTBase())[idx] != (void*)BufferBegin) {
934 DOUT << "JIT: GOT was out of date for " << (void*)BufferBegin
935 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx] << "\n";
936 ((void**)MemMgr->getGOTBase())[idx] = (void*)BufferBegin;
940 unsigned char *FnEnd = CurBufferPtr;
942 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, FnEnd);
943 BufferBegin = CurBufferPtr = 0;
944 NumBytes += FnEnd-FnStart;
946 // Invalidate the icache if necessary.
947 sys::Memory::InvalidateInstructionCache(FnStart, FnEnd-FnStart);
949 // Add it to the JIT symbol table if the host wants it.
950 AddFunctionToSymbolTable(F.getFunction()->getNameStart(),
951 FnStart, FnEnd-FnStart);
953 DOUT << "JIT: Finished CodeGen of [" << (void*)FnStart
954 << "] Function: " << F.getFunction()->getName()
955 << ": " << (FnEnd-FnStart) << " bytes of text, "
956 << Relocations.size() << " relocations\n";
959 // Mark code region readable and executable if it's not so already.
960 MemMgr->setMemoryExecutable();
964 DOUT << "JIT: Disassembled code:\n";
965 if (sys::hasDisassembler())
966 DOUT << sys::disassembleBuffer(FnStart, FnEnd-FnStart, (uintptr_t)FnStart);
970 unsigned char* q = FnStart;
971 for (i=1; q!=FnEnd; q++, i++) {
973 DOUT << "JIT: 0x" << (long)q << ": ";
974 DOUT<< std::setw(2) << std::setfill('0') << (unsigned short)*q << " ";
983 if (ExceptionHandling) {
984 uintptr_t ActualSize = 0;
985 SavedBufferBegin = BufferBegin;
986 SavedBufferEnd = BufferEnd;
987 SavedCurBufferPtr = CurBufferPtr;
989 if (MemMgr->NeedsExactSize()) {
990 ActualSize = DE->GetDwarfTableSizeInBytes(F, *this, FnStart, FnEnd);
993 BufferBegin = CurBufferPtr = MemMgr->startExceptionTable(F.getFunction(),
995 BufferEnd = BufferBegin+ActualSize;
996 unsigned char* FrameRegister = DE->EmitDwarfTable(F, *this, FnStart, FnEnd);
997 MemMgr->endExceptionTable(F.getFunction(), BufferBegin, CurBufferPtr,
999 BufferBegin = SavedBufferBegin;
1000 BufferEnd = SavedBufferEnd;
1001 CurBufferPtr = SavedCurBufferPtr;
1003 TheJIT->RegisterTable(FrameRegister);
1012 void* JITEmitter::allocateSpace(intptr_t Size, unsigned Alignment) {
1014 return MachineCodeEmitter::allocateSpace(Size, Alignment);
1016 // create a new memory block if there is no active one.
1017 // care must be taken so that BufferBegin is invalidated when a
1019 BufferBegin = CurBufferPtr = MemMgr->allocateSpace(Size, Alignment);
1020 BufferEnd = BufferBegin+Size;
1021 return CurBufferPtr;
1024 void JITEmitter::emitConstantPool(MachineConstantPool *MCP) {
1025 if (TheJIT->getJITInfo().hasCustomConstantPool())
1028 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
1029 if (Constants.empty()) return;
1031 MachineConstantPoolEntry CPE = Constants.back();
1032 unsigned Size = CPE.Offset;
1033 const Type *Ty = CPE.isMachineConstantPoolEntry()
1034 ? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal->getType();
1035 Size += TheJIT->getTargetData()->getABITypeSize(Ty);
1037 unsigned Align = 1 << MCP->getConstantPoolAlignment();
1038 ConstantPoolBase = allocateSpace(Size, Align);
1041 if (ConstantPoolBase == 0) return; // Buffer overflow.
1043 DOUT << "JIT: Emitted constant pool at [" << ConstantPoolBase
1044 << "] (size: " << Size << ", alignment: " << Align << ")\n";
1046 // Initialize the memory for all of the constant pool entries.
1047 for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
1048 void *CAddr = (char*)ConstantPoolBase+Constants[i].Offset;
1049 if (Constants[i].isMachineConstantPoolEntry()) {
1050 // FIXME: add support to lower machine constant pool values into bytes!
1051 cerr << "Initialize memory with machine specific constant pool entry"
1052 << " has not been implemented!\n";
1055 TheJIT->InitializeMemory(Constants[i].Val.ConstVal, CAddr);
1056 DOUT << "JIT: CP" << i << " at [" << CAddr << "]\n";
1060 void JITEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) {
1061 if (TheJIT->getJITInfo().hasCustomJumpTables())
1064 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1065 if (JT.empty()) return;
1067 unsigned NumEntries = 0;
1068 for (unsigned i = 0, e = JT.size(); i != e; ++i)
1069 NumEntries += JT[i].MBBs.size();
1071 unsigned EntrySize = MJTI->getEntrySize();
1073 // Just allocate space for all the jump tables now. We will fix up the actual
1074 // MBB entries in the tables after we emit the code for each block, since then
1075 // we will know the final locations of the MBBs in memory.
1077 JumpTableBase = allocateSpace(NumEntries * EntrySize, MJTI->getAlignment());
1080 void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) {
1081 if (TheJIT->getJITInfo().hasCustomJumpTables())
1084 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1085 if (JT.empty() || JumpTableBase == 0) return;
1087 if (TargetMachine::getRelocationModel() == Reloc::PIC_) {
1088 assert(MJTI->getEntrySize() == 4 && "Cross JIT'ing?");
1089 // For each jump table, place the offset from the beginning of the table
1090 // to the target address.
1091 int *SlotPtr = (int*)JumpTableBase;
1093 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1094 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1095 // Store the offset of the basic block for this jump table slot in the
1096 // memory we allocated for the jump table in 'initJumpTableInfo'
1097 intptr_t Base = (intptr_t)SlotPtr;
1098 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) {
1099 intptr_t MBBAddr = getMachineBasicBlockAddress(MBBs[mi]);
1100 *SlotPtr++ = TheJIT->getJITInfo().getPICJumpTableEntry(MBBAddr, Base);
1104 assert(MJTI->getEntrySize() == sizeof(void*) && "Cross JIT'ing?");
1106 // For each jump table, map each target in the jump table to the address of
1107 // an emitted MachineBasicBlock.
1108 intptr_t *SlotPtr = (intptr_t*)JumpTableBase;
1110 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1111 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1112 // Store the address of the basic block for this jump table slot in the
1113 // memory we allocated for the jump table in 'initJumpTableInfo'
1114 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi)
1115 *SlotPtr++ = getMachineBasicBlockAddress(MBBs[mi]);
1120 void JITEmitter::startFunctionStub(const GlobalValue* F, unsigned StubSize,
1121 unsigned Alignment) {
1122 SavedBufferBegin = BufferBegin;
1123 SavedBufferEnd = BufferEnd;
1124 SavedCurBufferPtr = CurBufferPtr;
1126 BufferBegin = CurBufferPtr = MemMgr->allocateStub(F, StubSize, Alignment);
1127 BufferEnd = BufferBegin+StubSize+1;
1130 void *JITEmitter::finishFunctionStub(const GlobalValue* F) {
1131 NumBytes += getCurrentPCOffset();
1133 // Invalidate the icache if necessary.
1134 sys::Memory::InvalidateInstructionCache(BufferBegin, NumBytes);
1136 std::swap(SavedBufferBegin, BufferBegin);
1137 BufferEnd = SavedBufferEnd;
1138 CurBufferPtr = SavedCurBufferPtr;
1139 return SavedBufferBegin;
1142 // getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry
1143 // in the constant pool that was last emitted with the 'emitConstantPool'
1146 intptr_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) const {
1147 assert(ConstantNum < ConstantPool->getConstants().size() &&
1148 "Invalid ConstantPoolIndex!");
1149 return (intptr_t)ConstantPoolBase +
1150 ConstantPool->getConstants()[ConstantNum].Offset;
1153 // getJumpTableEntryAddress - Return the address of the JumpTable with index
1154 // 'Index' in the jumpp table that was last initialized with 'initJumpTableInfo'
1156 intptr_t JITEmitter::getJumpTableEntryAddress(unsigned Index) const {
1157 const std::vector<MachineJumpTableEntry> &JT = JumpTable->getJumpTables();
1158 assert(Index < JT.size() && "Invalid jump table index!");
1160 unsigned Offset = 0;
1161 unsigned EntrySize = JumpTable->getEntrySize();
1163 for (unsigned i = 0; i < Index; ++i)
1164 Offset += JT[i].MBBs.size();
1166 Offset *= EntrySize;
1168 return (intptr_t)((char *)JumpTableBase + Offset);
1171 //===----------------------------------------------------------------------===//
1172 // Public interface to this file
1173 //===----------------------------------------------------------------------===//
1175 MachineCodeEmitter *JIT::createEmitter(JIT &jit, JITMemoryManager *JMM) {
1176 return new JITEmitter(jit, JMM);
1179 // getPointerToNamedFunction - This function is used as a global wrapper to
1180 // JIT::getPointerToNamedFunction for the purpose of resolving symbols when
1181 // bugpoint is debugging the JIT. In that scenario, we are loading an .so and
1182 // need to resolve function(s) that are being mis-codegenerated, so we need to
1183 // resolve their addresses at runtime, and this is the way to do it.
1185 void *getPointerToNamedFunction(const char *Name) {
1186 if (Function *F = TheJIT->FindFunctionNamed(Name))
1187 return TheJIT->getPointerToFunction(F);
1188 return TheJIT->getPointerToNamedFunction(Name);
1192 // getPointerToFunctionOrStub - If the specified function has been
1193 // code-gen'd, return a pointer to the function. If not, compile it, or use
1194 // a stub to implement lazy compilation if available.
1196 void *JIT::getPointerToFunctionOrStub(Function *F) {
1197 // If we have already code generated the function, just return the address.
1198 if (void *Addr = getPointerToGlobalIfAvailable(F))
1201 // Get a stub if the target supports it.
1202 assert(isa<JITEmitter>(MCE) && "Unexpected MCE?");
1203 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1204 return JE->getJITResolver().getFunctionStub(F);
1207 /// freeMachineCodeForFunction - release machine code memory for given Function.
1209 void JIT::freeMachineCodeForFunction(Function *F) {
1211 // Delete translation for this from the ExecutionEngine, so it will get
1212 // retranslated next time it is used.
1213 void *OldPtr = updateGlobalMapping(F, 0);
1216 RemoveFunctionFromSymbolTable(OldPtr);
1218 // Free the actual memory for the function body and related stuff.
1219 assert(isa<JITEmitter>(MCE) && "Unexpected MCE?");
1220 cast<JITEmitter>(MCE)->deallocateMemForFunction(F);