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/Statistic.h"
43 STATISTIC(NumBytes, "Number of bytes of machine code compiled");
44 STATISTIC(NumRelos, "Number of relocations applied");
45 static JIT *TheJIT = 0;
48 //===----------------------------------------------------------------------===//
49 // JIT lazy compilation code.
52 class JITResolverState {
54 /// FunctionToStubMap - Keep track of the stub created for a particular
55 /// function so that we can reuse them if necessary.
56 std::map<Function*, void*> FunctionToStubMap;
58 /// StubToFunctionMap - Keep track of the function that each stub
60 std::map<void*, Function*> StubToFunctionMap;
62 /// GlobalToLazyPtrMap - Keep track of the lazy pointer created for a
63 /// particular GlobalVariable so that we can reuse them if necessary.
64 std::map<GlobalValue*, void*> GlobalToLazyPtrMap;
67 std::map<Function*, void*>& getFunctionToStubMap(const MutexGuard& locked) {
68 assert(locked.holds(TheJIT->lock));
69 return FunctionToStubMap;
72 std::map<void*, Function*>& getStubToFunctionMap(const MutexGuard& locked) {
73 assert(locked.holds(TheJIT->lock));
74 return StubToFunctionMap;
77 std::map<GlobalValue*, void*>&
78 getGlobalToLazyPtrMap(const MutexGuard& locked) {
79 assert(locked.holds(TheJIT->lock));
80 return GlobalToLazyPtrMap;
84 /// JITResolver - Keep track of, and resolve, call sites for functions that
85 /// have not yet been compiled.
87 /// LazyResolverFn - The target lazy resolver function that we actually
88 /// rewrite instructions to use.
89 TargetJITInfo::LazyResolverFn LazyResolverFn;
91 JITResolverState state;
93 /// ExternalFnToStubMap - This is the equivalent of FunctionToStubMap for
94 /// external functions.
95 std::map<void*, void*> ExternalFnToStubMap;
97 //map addresses to indexes in the GOT
98 std::map<void*, unsigned> revGOTMap;
99 unsigned nextGOTIndex;
101 static JITResolver *TheJITResolver;
103 explicit JITResolver(JIT &jit) : nextGOTIndex(0) {
106 LazyResolverFn = jit.getJITInfo().getLazyResolverFunction(JITCompilerFn);
107 assert(TheJITResolver == 0 && "Multiple JIT resolvers?");
108 TheJITResolver = this;
115 /// getFunctionStub - This returns a pointer to a function stub, creating
116 /// one on demand as needed.
117 void *getFunctionStub(Function *F);
119 /// getExternalFunctionStub - Return a stub for the function at the
120 /// specified address, created lazily on demand.
121 void *getExternalFunctionStub(void *FnAddr);
123 /// getGlobalValueLazyPtr - Return a lazy pointer containing the specified
125 void *getGlobalValueLazyPtr(GlobalValue *V, void *GVAddress);
127 /// AddCallbackAtLocation - If the target is capable of rewriting an
128 /// instruction without the use of a stub, record the location of the use so
129 /// we know which function is being used at the location.
130 void *AddCallbackAtLocation(Function *F, void *Location) {
131 MutexGuard locked(TheJIT->lock);
132 /// Get the target-specific JIT resolver function.
133 state.getStubToFunctionMap(locked)[Location] = F;
134 return (void*)(intptr_t)LazyResolverFn;
137 /// getGOTIndexForAddress - Return a new or existing index in the GOT for
138 /// an address. This function only manages slots, it does not manage the
139 /// contents of the slots or the memory associated with the GOT.
140 unsigned getGOTIndexForAddr(void *addr);
142 /// JITCompilerFn - This function is called to resolve a stub to a compiled
143 /// address. If the LLVM Function corresponding to the stub has not yet
144 /// been compiled, this function compiles it first.
145 static void *JITCompilerFn(void *Stub);
149 JITResolver *JITResolver::TheJITResolver = 0;
151 /// getFunctionStub - This returns a pointer to a function stub, creating
152 /// one on demand as needed.
153 void *JITResolver::getFunctionStub(Function *F) {
154 MutexGuard locked(TheJIT->lock);
156 // If we already have a stub for this function, recycle it.
157 void *&Stub = state.getFunctionToStubMap(locked)[F];
158 if (Stub) return Stub;
160 // Call the lazy resolver function unless we already KNOW it is an external
161 // function, in which case we just skip the lazy resolution step.
162 void *Actual = (void*)(intptr_t)LazyResolverFn;
163 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode())
164 Actual = TheJIT->getPointerToFunction(F);
166 // Otherwise, codegen a new stub. For now, the stub will call the lazy
167 // resolver function.
168 Stub = TheJIT->getJITInfo().emitFunctionStub(F, Actual,
169 *TheJIT->getCodeEmitter());
171 if (Actual != (void*)(intptr_t)LazyResolverFn) {
172 // If we are getting the stub for an external function, we really want the
173 // address of the stub in the GlobalAddressMap for the JIT, not the address
174 // of the external function.
175 TheJIT->updateGlobalMapping(F, Stub);
178 DOUT << "JIT: Stub emitted at [" << Stub << "] for function '"
179 << F->getName() << "'\n";
181 // Finally, keep track of the stub-to-Function mapping so that the
182 // JITCompilerFn knows which function to compile!
183 state.getStubToFunctionMap(locked)[Stub] = F;
187 /// getGlobalValueLazyPtr - Return a lazy pointer containing the specified
189 void *JITResolver::getGlobalValueLazyPtr(GlobalValue *GV, void *GVAddress) {
190 MutexGuard locked(TheJIT->lock);
192 // If we already have a stub for this global variable, recycle it.
193 void *&LazyPtr = state.getGlobalToLazyPtrMap(locked)[GV];
194 if (LazyPtr) return LazyPtr;
196 // Otherwise, codegen a new lazy pointer.
197 LazyPtr = TheJIT->getJITInfo().emitGlobalValueLazyPtr(GV, GVAddress,
198 *TheJIT->getCodeEmitter());
200 DOUT << "JIT: Stub emitted at [" << LazyPtr << "] for GV '"
201 << GV->getName() << "'\n";
206 /// getExternalFunctionStub - Return a stub for the function at the
207 /// specified address, created lazily on demand.
208 void *JITResolver::getExternalFunctionStub(void *FnAddr) {
209 // If we already have a stub for this function, recycle it.
210 void *&Stub = ExternalFnToStubMap[FnAddr];
211 if (Stub) return Stub;
213 Stub = TheJIT->getJITInfo().emitFunctionStub(0, FnAddr,
214 *TheJIT->getCodeEmitter());
216 DOUT << "JIT: Stub emitted at [" << Stub
217 << "] for external function at '" << FnAddr << "'\n";
221 unsigned JITResolver::getGOTIndexForAddr(void* addr) {
222 unsigned idx = revGOTMap[addr];
224 idx = ++nextGOTIndex;
225 revGOTMap[addr] = idx;
226 DOUT << "Adding GOT entry " << idx << " for addr " << addr << "\n";
231 /// JITCompilerFn - This function is called when a lazy compilation stub has
232 /// been entered. It looks up which function this stub corresponds to, compiles
233 /// it if necessary, then returns the resultant function pointer.
234 void *JITResolver::JITCompilerFn(void *Stub) {
235 JITResolver &JR = *TheJITResolver;
237 MutexGuard locked(TheJIT->lock);
239 // The address given to us for the stub may not be exactly right, it might be
240 // a little bit after the stub. As such, use upper_bound to find it.
241 std::map<void*, Function*>::iterator I =
242 JR.state.getStubToFunctionMap(locked).upper_bound(Stub);
243 assert(I != JR.state.getStubToFunctionMap(locked).begin() &&
244 "This is not a known stub!");
245 Function *F = (--I)->second;
247 // If we have already code generated the function, just return the address.
248 void *Result = TheJIT->getPointerToGlobalIfAvailable(F);
251 // Otherwise we don't have it, do lazy compilation now.
253 // If lazy compilation is disabled, emit a useful error message and abort.
254 if (TheJIT->isLazyCompilationDisabled()) {
255 cerr << "LLVM JIT requested to do lazy compilation of function '"
256 << F->getName() << "' when lazy compiles are disabled!\n";
260 // We might like to remove the stub from the StubToFunction map.
261 // We can't do that! Multiple threads could be stuck, waiting to acquire the
262 // lock above. As soon as the 1st function finishes compiling the function,
263 // the next one will be released, and needs to be able to find the function
265 //JR.state.getStubToFunctionMap(locked).erase(I);
267 DOUT << "JIT: Lazily resolving function '" << F->getName()
268 << "' In stub ptr = " << Stub << " actual ptr = "
271 Result = TheJIT->getPointerToFunction(F);
274 // We don't need to reuse this stub in the future, as F is now compiled.
275 JR.state.getFunctionToStubMap(locked).erase(F);
277 // FIXME: We could rewrite all references to this stub if we knew them.
279 // What we will do is set the compiled function address to map to the
280 // same GOT entry as the stub so that later clients may update the GOT
281 // if they see it still using the stub address.
282 // Note: this is done so the Resolver doesn't have to manage GOT memory
283 // Do this without allocating map space if the target isn't using a GOT
284 if(JR.revGOTMap.find(Stub) != JR.revGOTMap.end())
285 JR.revGOTMap[Result] = JR.revGOTMap[Stub];
290 //===----------------------------------------------------------------------===//
291 // Function Index Support
293 // On MacOS we generate an index of currently JIT'd functions so that
294 // performance tools can determine a symbol name and accurate code range for a
295 // PC value. Because performance tools are generally asynchronous, the code
296 // below is written with the hope that it could be interrupted at any time and
297 // have useful answers. However, we don't go crazy with atomic operations, we
298 // just do a "reasonable effort".
300 #define ENABLE_JIT_SYMBOL_TABLE 0
303 /// JitSymbolEntry - Each function that is JIT compiled results in one of these
304 /// being added to an array of symbols. This indicates the name of the function
305 /// as well as the address range it occupies. This allows the client to map
306 /// from a PC value to the name of the function.
307 struct JitSymbolEntry {
308 const char *FnName; // FnName - a strdup'd string.
314 struct JitSymbolTable {
315 /// NextPtr - This forms a linked list of JitSymbolTable entries. This
316 /// pointer is not used right now, but might be used in the future. Consider
317 /// it reserved for future use.
318 JitSymbolTable *NextPtr;
320 /// Symbols - This is an array of JitSymbolEntry entries. Only the first
321 /// 'NumSymbols' symbols are valid.
322 JitSymbolEntry *Symbols;
324 /// NumSymbols - This indicates the number entries in the Symbols array that
328 /// NumAllocated - This indicates the amount of space we have in the Symbols
329 /// array. This is a private field that should not be read by external tools.
330 unsigned NumAllocated;
333 #if ENABLE_JIT_SYMBOL_TABLE
334 JitSymbolTable *__jitSymbolTable;
337 static void AddFunctionToSymbolTable(const char *FnName,
338 void *FnStart, intptr_t FnSize) {
339 assert(FnName != 0 && FnStart != 0 && "Bad symbol to add");
340 JitSymbolTable **SymTabPtrPtr = 0;
341 #if !ENABLE_JIT_SYMBOL_TABLE
344 SymTabPtrPtr = &__jitSymbolTable;
347 // If this is the first entry in the symbol table, add the JitSymbolTable
349 if (*SymTabPtrPtr == 0) {
350 JitSymbolTable *New = new JitSymbolTable();
354 New->NumAllocated = 0;
358 JitSymbolTable *SymTabPtr = *SymTabPtrPtr;
360 // If we have space in the table, reallocate the table.
361 if (SymTabPtr->NumSymbols >= SymTabPtr->NumAllocated) {
362 // If we don't have space, reallocate the table.
363 unsigned NewSize = std::max(64U, SymTabPtr->NumAllocated*2);
364 JitSymbolEntry *NewSymbols = new JitSymbolEntry[NewSize];
365 JitSymbolEntry *OldSymbols = SymTabPtr->Symbols;
367 // Copy the old entries over.
368 memcpy(NewSymbols, OldSymbols,
369 SymTabPtr->NumSymbols*sizeof(OldSymbols[0]));
371 // Swap the new symbols in, delete the old ones.
372 SymTabPtr->Symbols = NewSymbols;
373 SymTabPtr->NumAllocated = NewSize;
374 delete [] OldSymbols;
377 // Otherwise, we have enough space, just tack it onto the end of the array.
378 JitSymbolEntry &Entry = SymTabPtr->Symbols[SymTabPtr->NumSymbols];
379 Entry.FnName = strdup(FnName);
380 Entry.FnStart = FnStart;
381 Entry.FnSize = FnSize;
382 ++SymTabPtr->NumSymbols;
385 static void RemoveFunctionFromSymbolTable(void *FnStart) {
386 assert(FnStart && "Invalid function pointer");
387 JitSymbolTable **SymTabPtrPtr = 0;
388 #if !ENABLE_JIT_SYMBOL_TABLE
391 SymTabPtrPtr = &__jitSymbolTable;
394 JitSymbolTable *SymTabPtr = *SymTabPtrPtr;
395 JitSymbolEntry *Symbols = SymTabPtr->Symbols;
397 // Scan the table to find its index. The table is not sorted, so do a linear
400 for (Index = 0; Symbols[Index].FnStart != FnStart; ++Index)
401 assert(Index != SymTabPtr->NumSymbols && "Didn't find function!");
403 // Once we have an index, we know to nuke this entry, overwrite it with the
404 // entry at the end of the array, making the last entry redundant.
405 const char *OldName = Symbols[Index].FnName;
406 Symbols[Index] = Symbols[SymTabPtr->NumSymbols-1];
407 free((void*)OldName);
409 // Drop the number of symbols in the table.
410 --SymTabPtr->NumSymbols;
412 // Finally, if we deleted the final symbol, deallocate the table itself.
413 if (SymTabPtr->NumSymbols != 0)
421 //===----------------------------------------------------------------------===//
425 /// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is
426 /// used to output functions to memory for execution.
427 class JITEmitter : public MachineCodeEmitter {
428 JITMemoryManager *MemMgr;
430 // When outputting a function stub in the context of some other function, we
431 // save BufferBegin/BufferEnd/CurBufferPtr here.
432 unsigned char *SavedBufferBegin, *SavedBufferEnd, *SavedCurBufferPtr;
434 /// Relocations - These are the relocations that the function needs, as
436 std::vector<MachineRelocation> Relocations;
438 /// MBBLocations - This vector is a mapping from MBB ID's to their address.
439 /// It is filled in by the StartMachineBasicBlock callback and queried by
440 /// the getMachineBasicBlockAddress callback.
441 std::vector<intptr_t> MBBLocations;
443 /// ConstantPool - The constant pool for the current function.
445 MachineConstantPool *ConstantPool;
447 /// ConstantPoolBase - A pointer to the first entry in the constant pool.
449 void *ConstantPoolBase;
451 /// JumpTable - The jump tables for the current function.
453 MachineJumpTableInfo *JumpTable;
455 /// JumpTableBase - A pointer to the first entry in the jump table.
459 /// Resolver - This contains info about the currently resolved functions.
460 JITResolver Resolver;
462 /// DE - The dwarf emitter for the jit.
465 /// LabelLocations - This vector is a mapping from Label ID's to their
467 std::vector<intptr_t> LabelLocations;
469 /// MMI - Machine module info for exception informations
470 MachineModuleInfo* MMI;
472 // GVSet - a set to keep track of which globals have been seen
473 std::set<const GlobalVariable*> GVSet;
476 JITEmitter(JIT &jit, JITMemoryManager *JMM) : Resolver(jit) {
477 MemMgr = JMM ? JMM : JITMemoryManager::CreateDefaultMemManager();
478 if (jit.getJITInfo().needsGOT()) {
479 MemMgr->AllocateGOT();
480 DOUT << "JIT is managing a GOT\n";
483 if (ExceptionHandling) DE = new JITDwarfEmitter(jit);
487 if (ExceptionHandling) delete DE;
490 /// classof - Methods for support type inquiry through isa, cast, and
493 static inline bool classof(const JITEmitter*) { return true; }
494 static inline bool classof(const MachineCodeEmitter*) { return true; }
496 JITResolver &getJITResolver() { return Resolver; }
498 virtual void startFunction(MachineFunction &F);
499 virtual bool finishFunction(MachineFunction &F);
501 void emitConstantPool(MachineConstantPool *MCP);
502 void initJumpTableInfo(MachineJumpTableInfo *MJTI);
503 void emitJumpTableInfo(MachineJumpTableInfo *MJTI);
505 virtual void startFunctionStub(const GlobalValue* F, unsigned StubSize,
506 unsigned Alignment = 1);
507 virtual void* finishFunctionStub(const GlobalValue *F);
509 virtual void addRelocation(const MachineRelocation &MR) {
510 Relocations.push_back(MR);
513 virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {
514 if (MBBLocations.size() <= (unsigned)MBB->getNumber())
515 MBBLocations.resize((MBB->getNumber()+1)*2);
516 MBBLocations[MBB->getNumber()] = getCurrentPCValue();
519 virtual intptr_t getConstantPoolEntryAddress(unsigned Entry) const;
520 virtual intptr_t getJumpTableEntryAddress(unsigned Entry) const;
522 virtual intptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const {
523 assert(MBBLocations.size() > (unsigned)MBB->getNumber() &&
524 MBBLocations[MBB->getNumber()] && "MBB not emitted!");
525 return MBBLocations[MBB->getNumber()];
528 /// deallocateMemForFunction - Deallocate all memory for the specified
530 void deallocateMemForFunction(Function *F) {
531 MemMgr->deallocateMemForFunction(F);
534 virtual void emitLabel(uint64_t LabelID) {
535 if (LabelLocations.size() <= LabelID)
536 LabelLocations.resize((LabelID+1)*2);
537 LabelLocations[LabelID] = getCurrentPCValue();
540 virtual intptr_t getLabelAddress(uint64_t LabelID) const {
541 assert(LabelLocations.size() > (unsigned)LabelID &&
542 LabelLocations[LabelID] && "Label not emitted!");
543 return LabelLocations[LabelID];
546 virtual void setModuleInfo(MachineModuleInfo* Info) {
548 if (ExceptionHandling) DE->setModuleInfo(Info);
552 void *getPointerToGlobal(GlobalValue *GV, void *Reference, bool NoNeedStub);
553 void *getPointerToGVLazyPtr(GlobalValue *V, void *Reference,
555 unsigned addSizeOfGlobal(const GlobalVariable *GV, unsigned Size);
556 unsigned addSizeOfGlobalsInConstantVal(const Constant *C, unsigned Size);
557 unsigned addSizeOfGlobalsInInitializer(const Constant *Init, unsigned Size);
558 unsigned GetSizeOfGlobalsInBytes(MachineFunction &MF);
562 void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference,
563 bool DoesntNeedStub) {
564 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) {
565 /// FIXME: If we straightened things out, this could actually emit the
566 /// global immediately instead of queuing it for codegen later!
567 return TheJIT->getOrEmitGlobalVariable(GV);
569 if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
570 return TheJIT->getPointerToGlobal(GA->resolveAliasedGlobal(false));
572 // If we have already compiled the function, return a pointer to its body.
573 Function *F = cast<Function>(V);
574 void *ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F);
575 if (ResultPtr) return ResultPtr;
577 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode()) {
578 // If this is an external function pointer, we can force the JIT to
579 // 'compile' it, which really just adds it to the map.
581 return TheJIT->getPointerToFunction(F);
583 return Resolver.getFunctionStub(F);
586 // Okay, the function has not been compiled yet, if the target callback
587 // mechanism is capable of rewriting the instruction directly, prefer to do
588 // that instead of emitting a stub.
590 return Resolver.AddCallbackAtLocation(F, Reference);
592 // Otherwise, we have to emit a lazy resolving stub.
593 return Resolver.getFunctionStub(F);
596 void *JITEmitter::getPointerToGVLazyPtr(GlobalValue *V, void *Reference,
597 bool DoesntNeedStub) {
598 // Make sure GV is emitted first.
599 // FIXME: For now, if the GV is an external function we force the JIT to
600 // compile it so the lazy pointer will contain the fully resolved address.
601 void *GVAddress = getPointerToGlobal(V, Reference, true);
602 return Resolver.getGlobalValueLazyPtr(V, GVAddress);
605 static unsigned GetConstantPoolSizeInBytes(MachineConstantPool *MCP) {
606 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
607 if (Constants.empty()) return 0;
609 MachineConstantPoolEntry CPE = Constants.back();
610 unsigned Size = CPE.Offset;
611 const Type *Ty = CPE.isMachineConstantPoolEntry()
612 ? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal->getType();
613 Size += TheJIT->getTargetData()->getABITypeSize(Ty);
617 static unsigned GetJumpTableSizeInBytes(MachineJumpTableInfo *MJTI) {
618 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
619 if (JT.empty()) return 0;
621 unsigned NumEntries = 0;
622 for (unsigned i = 0, e = JT.size(); i != e; ++i)
623 NumEntries += JT[i].MBBs.size();
625 unsigned EntrySize = MJTI->getEntrySize();
627 return NumEntries * EntrySize;
630 static uintptr_t RoundUpToAlign(uintptr_t Size, unsigned Alignment) {
631 if (Alignment == 0) Alignment = 1;
632 // Since we do not know where the buffer will be allocated, be pessimistic.
633 return Size + Alignment;
636 /// addSizeOfGlobal - add the size of the global (plus any alignment padding)
637 /// into the running total Size.
639 unsigned JITEmitter::addSizeOfGlobal(const GlobalVariable *GV, unsigned Size) {
640 const Type *ElTy = GV->getType()->getElementType();
641 size_t GVSize = (size_t)TheJIT->getTargetData()->getABITypeSize(ElTy);
643 (size_t)TheJIT->getTargetData()->getPreferredAlignment(GV);
644 DOUT << "Adding in size " << GVSize << " alignment " << GVAlign;
646 // Assume code section ends with worst possible alignment, so first
647 // variable needs maximal padding.
650 Size = ((Size+GVAlign-1)/GVAlign)*GVAlign;
655 /// addSizeOfGlobalsInConstantVal - find any globals that we haven't seen yet
656 /// but are referenced from the constant; put them in GVSet and add their
657 /// size into the running total Size.
659 unsigned JITEmitter::addSizeOfGlobalsInConstantVal(const Constant *C,
661 // If its undefined, return the garbage.
662 if (isa<UndefValue>(C))
665 // If the value is a ConstantExpr
666 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
667 Constant *Op0 = CE->getOperand(0);
668 switch (CE->getOpcode()) {
669 case Instruction::GetElementPtr:
670 case Instruction::Trunc:
671 case Instruction::ZExt:
672 case Instruction::SExt:
673 case Instruction::FPTrunc:
674 case Instruction::FPExt:
675 case Instruction::UIToFP:
676 case Instruction::SIToFP:
677 case Instruction::FPToUI:
678 case Instruction::FPToSI:
679 case Instruction::PtrToInt:
680 case Instruction::IntToPtr:
681 case Instruction::BitCast: {
682 Size = addSizeOfGlobalsInConstantVal(Op0, Size);
685 case Instruction::Add:
686 case Instruction::Sub:
687 case Instruction::Mul:
688 case Instruction::UDiv:
689 case Instruction::SDiv:
690 case Instruction::URem:
691 case Instruction::SRem:
692 case Instruction::And:
693 case Instruction::Or:
694 case Instruction::Xor: {
695 Size = addSizeOfGlobalsInConstantVal(Op0, Size);
696 Size = addSizeOfGlobalsInConstantVal(CE->getOperand(1), Size);
700 cerr << "ConstantExpr not handled: " << *CE << "\n";
706 if (C->getType()->getTypeID() == Type::PointerTyID)
707 if (const GlobalVariable* GV = dyn_cast<GlobalVariable>(C))
708 if (GVSet.insert(GV).second)
709 Size = addSizeOfGlobal(GV, Size);
714 /// addSizeOfGLobalsInInitializer - handle any globals that we haven't seen yet
715 /// but are referenced from the given initializer.
717 unsigned JITEmitter::addSizeOfGlobalsInInitializer(const Constant *Init,
719 if (!isa<UndefValue>(Init) &&
720 !isa<ConstantVector>(Init) &&
721 !isa<ConstantAggregateZero>(Init) &&
722 !isa<ConstantArray>(Init) &&
723 !isa<ConstantStruct>(Init) &&
724 Init->getType()->isFirstClassType())
725 Size = addSizeOfGlobalsInConstantVal(Init, Size);
729 /// GetSizeOfGlobalsInBytes - walk the code for the function, looking for
730 /// globals; then walk the initializers of those globals looking for more.
731 /// If their size has not been considered yet, add it into the running total
734 unsigned JITEmitter::GetSizeOfGlobalsInBytes(MachineFunction &MF) {
738 for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
740 for (MachineBasicBlock::const_iterator I = MBB->begin(), E = MBB->end();
742 const TargetInstrDesc &Desc = I->getDesc();
743 const MachineInstr &MI = *I;
744 unsigned NumOps = Desc.getNumOperands();
745 for (unsigned CurOp = 0; CurOp < NumOps; CurOp++) {
746 const MachineOperand &MO = MI.getOperand(CurOp);
747 if (MO.isGlobalAddress()) {
748 GlobalValue* V = MO.getGlobal();
749 const GlobalVariable *GV = dyn_cast<const GlobalVariable>(V);
752 // If seen in previous function, it will have an entry here.
753 if (TheJIT->getPointerToGlobalIfAvailable(GV))
755 // If seen earlier in this function, it will have an entry here.
756 // FIXME: it should be possible to combine these tables, by
757 // assuming the addresses of the new globals in this module
758 // start at 0 (or something) and adjusting them after codegen
759 // complete. Another possibility is to grab a marker bit in GV.
760 if (GVSet.insert(GV).second)
761 // A variable as yet unseen. Add in its size.
762 Size = addSizeOfGlobal(GV, Size);
767 DOUT << "About to look through initializers\n";
768 // Look for more globals that are referenced only from initializers.
769 // GVSet.end is computed each time because the set can grow as we go.
770 for (std::set<const GlobalVariable *>::iterator I = GVSet.begin();
771 I != GVSet.end(); I++) {
772 const GlobalVariable* GV = *I;
773 if (GV->hasInitializer())
774 Size = addSizeOfGlobalsInInitializer(GV->getInitializer(), Size);
780 void JITEmitter::startFunction(MachineFunction &F) {
781 uintptr_t ActualSize = 0;
782 if (MemMgr->NeedsExactSize()) {
783 DOUT << "ExactSize\n";
784 const TargetInstrInfo* TII = F.getTarget().getInstrInfo();
785 MachineJumpTableInfo *MJTI = F.getJumpTableInfo();
786 MachineConstantPool *MCP = F.getConstantPool();
788 // Ensure the constant pool/jump table info is at least 4-byte aligned.
789 ActualSize = RoundUpToAlign(ActualSize, 16);
791 // Add the alignment of the constant pool
792 ActualSize = RoundUpToAlign(ActualSize,
793 1 << MCP->getConstantPoolAlignment());
795 // Add the constant pool size
796 ActualSize += GetConstantPoolSizeInBytes(MCP);
798 // Add the aligment of the jump table info
799 ActualSize = RoundUpToAlign(ActualSize, MJTI->getAlignment());
801 // Add the jump table size
802 ActualSize += GetJumpTableSizeInBytes(MJTI);
804 // Add the alignment for the function
805 ActualSize = RoundUpToAlign(ActualSize,
806 std::max(F.getFunction()->getAlignment(), 8U));
808 // Add the function size
809 ActualSize += TII->GetFunctionSizeInBytes(F);
811 DOUT << "ActualSize before globals " << ActualSize << "\n";
812 // Add the size of the globals that will be allocated after this function.
813 // These are all the ones referenced from this function that were not
814 // previously allocated.
815 ActualSize += GetSizeOfGlobalsInBytes(F);
816 DOUT << "ActualSize after globals " << ActualSize << "\n";
819 BufferBegin = CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(),
821 BufferEnd = BufferBegin+ActualSize;
823 // Ensure the constant pool/jump table info is at least 4-byte aligned.
826 emitConstantPool(F.getConstantPool());
827 initJumpTableInfo(F.getJumpTableInfo());
829 // About to start emitting the machine code for the function.
830 emitAlignment(std::max(F.getFunction()->getAlignment(), 8U));
831 TheJIT->updateGlobalMapping(F.getFunction(), CurBufferPtr);
833 MBBLocations.clear();
836 bool JITEmitter::finishFunction(MachineFunction &F) {
837 if (CurBufferPtr == BufferEnd) {
838 // FIXME: Allocate more space, then try again.
839 cerr << "JIT: Ran out of space for generated machine code!\n";
843 emitJumpTableInfo(F.getJumpTableInfo());
845 // FnStart is the start of the text, not the start of the constant pool and
846 // other per-function data.
847 unsigned char *FnStart =
848 (unsigned char *)TheJIT->getPointerToGlobalIfAvailable(F.getFunction());
850 if (!Relocations.empty()) {
851 NumRelos += Relocations.size();
853 // Resolve the relocations to concrete pointers.
854 for (unsigned i = 0, e = Relocations.size(); i != e; ++i) {
855 MachineRelocation &MR = Relocations[i];
858 ResultPtr = TheJIT->getPointerToNamedFunction(MR.getString());
860 // If the target REALLY wants a stub for this function, emit it now.
861 if (!MR.doesntNeedStub())
862 ResultPtr = Resolver.getExternalFunctionStub(ResultPtr);
863 } else if (MR.isGlobalValue()) {
864 ResultPtr = getPointerToGlobal(MR.getGlobalValue(),
865 BufferBegin+MR.getMachineCodeOffset(),
866 MR.doesntNeedStub());
867 } else if (MR.isGlobalValueLazyPtr()) {
868 ResultPtr = getPointerToGVLazyPtr(MR.getGlobalValue(),
869 BufferBegin+MR.getMachineCodeOffset(),
870 MR.doesntNeedStub());
871 } else if (MR.isBasicBlock()) {
872 ResultPtr = (void*)getMachineBasicBlockAddress(MR.getBasicBlock());
873 } else if (MR.isConstantPoolIndex()) {
874 ResultPtr=(void*)getConstantPoolEntryAddress(MR.getConstantPoolIndex());
876 assert(MR.isJumpTableIndex());
877 ResultPtr=(void*)getJumpTableEntryAddress(MR.getJumpTableIndex());
880 MR.setResultPointer(ResultPtr);
882 // if we are managing the GOT and the relocation wants an index,
884 if (MR.isGOTRelative() && MemMgr->isManagingGOT()) {
885 unsigned idx = Resolver.getGOTIndexForAddr(ResultPtr);
887 if (((void**)MemMgr->getGOTBase())[idx] != ResultPtr) {
888 DOUT << "GOT was out of date for " << ResultPtr
889 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
891 ((void**)MemMgr->getGOTBase())[idx] = ResultPtr;
896 TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0],
897 Relocations.size(), MemMgr->getGOTBase());
900 unsigned char *FnEnd = CurBufferPtr;
902 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, FnEnd);
903 NumBytes += FnEnd-FnStart;
905 // Update the GOT entry for F to point to the new code.
906 if (MemMgr->isManagingGOT()) {
907 unsigned idx = Resolver.getGOTIndexForAddr((void*)BufferBegin);
908 if (((void**)MemMgr->getGOTBase())[idx] != (void*)BufferBegin) {
909 DOUT << "GOT was out of date for " << (void*)BufferBegin
910 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx] << "\n";
911 ((void**)MemMgr->getGOTBase())[idx] = (void*)BufferBegin;
915 // Invalidate the icache if necessary.
916 sys::Memory::InvalidateInstructionCache(FnStart, FnEnd-FnStart);
918 // Add it to the JIT symbol table if the host wants it.
919 AddFunctionToSymbolTable(F.getFunction()->getNameStart(),
920 FnStart, FnEnd-FnStart);
922 DOUT << "JIT: Finished CodeGen of [" << (void*)FnStart
923 << "] Function: " << F.getFunction()->getName()
924 << ": " << (FnEnd-FnStart) << " bytes of text, "
925 << Relocations.size() << " relocations\n";
928 // Mark code region readable and executable if it's not so already.
929 sys::Memory::SetRXPrivilege(FnStart, FnEnd-FnStart);
935 unsigned char* q = FnStart;
936 for (i=1; q!=FnEnd; q++, i++) {
938 DOUT << "0x" << (long)q << ": ";
939 DOUT<< (unsigned short)*q << " ";
944 if (sys::hasDisassembler())
945 DOUT << "Disassembled code:\n"
946 << sys::disassembleBuffer(FnStart, FnEnd-FnStart, (uintptr_t)FnStart);
949 if (ExceptionHandling) {
950 uintptr_t ActualSize = 0;
951 SavedBufferBegin = BufferBegin;
952 SavedBufferEnd = BufferEnd;
953 SavedCurBufferPtr = CurBufferPtr;
955 if (MemMgr->NeedsExactSize()) {
956 ActualSize = DE->GetDwarfTableSizeInBytes(F, *this, FnStart, FnEnd);
959 BufferBegin = CurBufferPtr = MemMgr->startExceptionTable(F.getFunction(),
961 BufferEnd = BufferBegin+ActualSize;
962 unsigned char* FrameRegister = DE->EmitDwarfTable(F, *this, FnStart, FnEnd);
963 MemMgr->endExceptionTable(F.getFunction(), BufferBegin, CurBufferPtr,
965 BufferBegin = SavedBufferBegin;
966 BufferEnd = SavedBufferEnd;
967 CurBufferPtr = SavedCurBufferPtr;
969 TheJIT->RegisterTable(FrameRegister);
978 void JITEmitter::emitConstantPool(MachineConstantPool *MCP) {
979 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
980 if (Constants.empty()) return;
982 MachineConstantPoolEntry CPE = Constants.back();
983 unsigned Size = CPE.Offset;
984 const Type *Ty = CPE.isMachineConstantPoolEntry()
985 ? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal->getType();
986 Size += TheJIT->getTargetData()->getABITypeSize(Ty);
988 unsigned Align = 1 << MCP->getConstantPoolAlignment();
989 ConstantPoolBase = allocateSpace(Size, Align);
992 if (ConstantPoolBase == 0) return; // Buffer overflow.
994 DOUT << "JIT: Emitted constant pool at [" << ConstantPoolBase
995 << "] (size: " << Size << ", alignment: " << Align << ")\n";
997 // Initialize the memory for all of the constant pool entries.
998 for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
999 void *CAddr = (char*)ConstantPoolBase+Constants[i].Offset;
1000 if (Constants[i].isMachineConstantPoolEntry()) {
1001 // FIXME: add support to lower machine constant pool values into bytes!
1002 cerr << "Initialize memory with machine specific constant pool entry"
1003 << " has not been implemented!\n";
1006 TheJIT->InitializeMemory(Constants[i].Val.ConstVal, CAddr);
1007 DOUT << "JIT: CP" << i << " at [" << CAddr << "]\n";
1011 void JITEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) {
1012 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1013 if (JT.empty()) return;
1015 unsigned NumEntries = 0;
1016 for (unsigned i = 0, e = JT.size(); i != e; ++i)
1017 NumEntries += JT[i].MBBs.size();
1019 unsigned EntrySize = MJTI->getEntrySize();
1021 // Just allocate space for all the jump tables now. We will fix up the actual
1022 // MBB entries in the tables after we emit the code for each block, since then
1023 // we will know the final locations of the MBBs in memory.
1025 JumpTableBase = allocateSpace(NumEntries * EntrySize, MJTI->getAlignment());
1028 void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) {
1029 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1030 if (JT.empty() || JumpTableBase == 0) return;
1032 if (TargetMachine::getRelocationModel() == Reloc::PIC_) {
1033 assert(MJTI->getEntrySize() == 4 && "Cross JIT'ing?");
1034 // For each jump table, place the offset from the beginning of the table
1035 // to the target address.
1036 int *SlotPtr = (int*)JumpTableBase;
1038 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1039 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1040 // Store the offset of the basic block for this jump table slot in the
1041 // memory we allocated for the jump table in 'initJumpTableInfo'
1042 intptr_t Base = (intptr_t)SlotPtr;
1043 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) {
1044 intptr_t MBBAddr = getMachineBasicBlockAddress(MBBs[mi]);
1045 *SlotPtr++ = TheJIT->getJITInfo().getPICJumpTableEntry(MBBAddr, Base);
1049 assert(MJTI->getEntrySize() == sizeof(void*) && "Cross JIT'ing?");
1051 // For each jump table, map each target in the jump table to the address of
1052 // an emitted MachineBasicBlock.
1053 intptr_t *SlotPtr = (intptr_t*)JumpTableBase;
1055 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1056 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1057 // Store the address of the basic block for this jump table slot in the
1058 // memory we allocated for the jump table in 'initJumpTableInfo'
1059 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi)
1060 *SlotPtr++ = getMachineBasicBlockAddress(MBBs[mi]);
1065 void JITEmitter::startFunctionStub(const GlobalValue* F, unsigned StubSize,
1066 unsigned Alignment) {
1067 SavedBufferBegin = BufferBegin;
1068 SavedBufferEnd = BufferEnd;
1069 SavedCurBufferPtr = CurBufferPtr;
1071 BufferBegin = CurBufferPtr = MemMgr->allocateStub(F, StubSize, Alignment);
1072 BufferEnd = BufferBegin+StubSize+1;
1075 void *JITEmitter::finishFunctionStub(const GlobalValue* F) {
1076 NumBytes += getCurrentPCOffset();
1077 std::swap(SavedBufferBegin, BufferBegin);
1078 BufferEnd = SavedBufferEnd;
1079 CurBufferPtr = SavedCurBufferPtr;
1080 return SavedBufferBegin;
1083 // getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry
1084 // in the constant pool that was last emitted with the 'emitConstantPool'
1087 intptr_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) const {
1088 assert(ConstantNum < ConstantPool->getConstants().size() &&
1089 "Invalid ConstantPoolIndex!");
1090 return (intptr_t)ConstantPoolBase +
1091 ConstantPool->getConstants()[ConstantNum].Offset;
1094 // getJumpTableEntryAddress - Return the address of the JumpTable with index
1095 // 'Index' in the jumpp table that was last initialized with 'initJumpTableInfo'
1097 intptr_t JITEmitter::getJumpTableEntryAddress(unsigned Index) const {
1098 const std::vector<MachineJumpTableEntry> &JT = JumpTable->getJumpTables();
1099 assert(Index < JT.size() && "Invalid jump table index!");
1101 unsigned Offset = 0;
1102 unsigned EntrySize = JumpTable->getEntrySize();
1104 for (unsigned i = 0; i < Index; ++i)
1105 Offset += JT[i].MBBs.size();
1107 Offset *= EntrySize;
1109 return (intptr_t)((char *)JumpTableBase + Offset);
1112 //===----------------------------------------------------------------------===//
1113 // Public interface to this file
1114 //===----------------------------------------------------------------------===//
1116 MachineCodeEmitter *JIT::createEmitter(JIT &jit, JITMemoryManager *JMM) {
1117 return new JITEmitter(jit, JMM);
1120 // getPointerToNamedFunction - This function is used as a global wrapper to
1121 // JIT::getPointerToNamedFunction for the purpose of resolving symbols when
1122 // bugpoint is debugging the JIT. In that scenario, we are loading an .so and
1123 // need to resolve function(s) that are being mis-codegenerated, so we need to
1124 // resolve their addresses at runtime, and this is the way to do it.
1126 void *getPointerToNamedFunction(const char *Name) {
1127 if (Function *F = TheJIT->FindFunctionNamed(Name))
1128 return TheJIT->getPointerToFunction(F);
1129 return TheJIT->getPointerToNamedFunction(Name);
1133 // getPointerToFunctionOrStub - If the specified function has been
1134 // code-gen'd, return a pointer to the function. If not, compile it, or use
1135 // a stub to implement lazy compilation if available.
1137 void *JIT::getPointerToFunctionOrStub(Function *F) {
1138 // If we have already code generated the function, just return the address.
1139 if (void *Addr = getPointerToGlobalIfAvailable(F))
1142 // Get a stub if the target supports it.
1143 assert(isa<JITEmitter>(MCE) && "Unexpected MCE?");
1144 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1145 return JE->getJITResolver().getFunctionStub(F);
1148 /// freeMachineCodeForFunction - release machine code memory for given Function.
1150 void JIT::freeMachineCodeForFunction(Function *F) {
1152 // Delete translation for this from the ExecutionEngine, so it will get
1153 // retranslated next time it is used.
1154 void *OldPtr = updateGlobalMapping(F, 0);
1157 RemoveFunctionFromSymbolTable(OldPtr);
1159 // Free the actual memory for the function body and related stuff.
1160 assert(isa<JITEmitter>(MCE) && "Unexpected MCE?");
1161 cast<JITEmitter>(MCE)->deallocateMemForFunction(F);