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;
241 // Only lock for getting the Function. The call getPointerToFunction made
242 // in this function might trigger function materializing, which requires
243 // JIT lock to be unlocked.
244 MutexGuard locked(TheJIT->lock);
246 // The address given to us for the stub may not be exactly right, it might be
247 // a little bit after the stub. As such, use upper_bound to find it.
248 std::map<void*, Function*>::iterator I =
249 JR.state.getStubToFunctionMap(locked).upper_bound(Stub);
250 assert(I != JR.state.getStubToFunctionMap(locked).begin() &&
251 "This is not a known stub!");
253 ActualPtr = I->first;
256 // If we have already code generated the function, just return the address.
257 void *Result = TheJIT->getPointerToGlobalIfAvailable(F);
260 // Otherwise we don't have it, do lazy compilation now.
262 // If lazy compilation is disabled, emit a useful error message and abort.
263 if (TheJIT->isLazyCompilationDisabled()) {
264 cerr << "LLVM JIT requested to do lazy compilation of function '"
265 << F->getName() << "' when lazy compiles are disabled!\n";
269 // We might like to remove the stub from the StubToFunction map.
270 // We can't do that! Multiple threads could be stuck, waiting to acquire the
271 // lock above. As soon as the 1st function finishes compiling the function,
272 // the next one will be released, and needs to be able to find the function
274 //JR.state.getStubToFunctionMap(locked).erase(I);
276 DOUT << "JIT: Lazily resolving function '" << F->getName()
277 << "' In stub ptr = " << Stub << " actual ptr = "
278 << ActualPtr << "\n";
280 Result = TheJIT->getPointerToFunction(F);
283 // Reacquire the lock to erase the stub in the map.
284 MutexGuard locked(TheJIT->lock);
286 // We don't need to reuse this stub in the future, as F is now compiled.
287 JR.state.getFunctionToStubMap(locked).erase(F);
289 // FIXME: We could rewrite all references to this stub if we knew them.
291 // What we will do is set the compiled function address to map to the
292 // same GOT entry as the stub so that later clients may update the GOT
293 // if they see it still using the stub address.
294 // Note: this is done so the Resolver doesn't have to manage GOT memory
295 // Do this without allocating map space if the target isn't using a GOT
296 if(JR.revGOTMap.find(Stub) != JR.revGOTMap.end())
297 JR.revGOTMap[Result] = JR.revGOTMap[Stub];
302 //===----------------------------------------------------------------------===//
303 // Function Index Support
305 // On MacOS we generate an index of currently JIT'd functions so that
306 // performance tools can determine a symbol name and accurate code range for a
307 // PC value. Because performance tools are generally asynchronous, the code
308 // below is written with the hope that it could be interrupted at any time and
309 // have useful answers. However, we don't go crazy with atomic operations, we
310 // just do a "reasonable effort".
312 #define ENABLE_JIT_SYMBOL_TABLE 0
315 /// JitSymbolEntry - Each function that is JIT compiled results in one of these
316 /// being added to an array of symbols. This indicates the name of the function
317 /// as well as the address range it occupies. This allows the client to map
318 /// from a PC value to the name of the function.
319 struct JitSymbolEntry {
320 const char *FnName; // FnName - a strdup'd string.
326 struct JitSymbolTable {
327 /// NextPtr - This forms a linked list of JitSymbolTable entries. This
328 /// pointer is not used right now, but might be used in the future. Consider
329 /// it reserved for future use.
330 JitSymbolTable *NextPtr;
332 /// Symbols - This is an array of JitSymbolEntry entries. Only the first
333 /// 'NumSymbols' symbols are valid.
334 JitSymbolEntry *Symbols;
336 /// NumSymbols - This indicates the number entries in the Symbols array that
340 /// NumAllocated - This indicates the amount of space we have in the Symbols
341 /// array. This is a private field that should not be read by external tools.
342 unsigned NumAllocated;
345 #if ENABLE_JIT_SYMBOL_TABLE
346 JitSymbolTable *__jitSymbolTable;
349 static void AddFunctionToSymbolTable(const char *FnName,
350 void *FnStart, intptr_t FnSize) {
351 assert(FnName != 0 && FnStart != 0 && "Bad symbol to add");
352 JitSymbolTable **SymTabPtrPtr = 0;
353 #if !ENABLE_JIT_SYMBOL_TABLE
356 SymTabPtrPtr = &__jitSymbolTable;
359 // If this is the first entry in the symbol table, add the JitSymbolTable
361 if (*SymTabPtrPtr == 0) {
362 JitSymbolTable *New = new JitSymbolTable();
366 New->NumAllocated = 0;
370 JitSymbolTable *SymTabPtr = *SymTabPtrPtr;
372 // If we have space in the table, reallocate the table.
373 if (SymTabPtr->NumSymbols >= SymTabPtr->NumAllocated) {
374 // If we don't have space, reallocate the table.
375 unsigned NewSize = std::max(64U, SymTabPtr->NumAllocated*2);
376 JitSymbolEntry *NewSymbols = new JitSymbolEntry[NewSize];
377 JitSymbolEntry *OldSymbols = SymTabPtr->Symbols;
379 // Copy the old entries over.
380 memcpy(NewSymbols, OldSymbols,
381 SymTabPtr->NumSymbols*sizeof(OldSymbols[0]));
383 // Swap the new symbols in, delete the old ones.
384 SymTabPtr->Symbols = NewSymbols;
385 SymTabPtr->NumAllocated = NewSize;
386 delete [] OldSymbols;
389 // Otherwise, we have enough space, just tack it onto the end of the array.
390 JitSymbolEntry &Entry = SymTabPtr->Symbols[SymTabPtr->NumSymbols];
391 Entry.FnName = strdup(FnName);
392 Entry.FnStart = FnStart;
393 Entry.FnSize = FnSize;
394 ++SymTabPtr->NumSymbols;
397 static void RemoveFunctionFromSymbolTable(void *FnStart) {
398 assert(FnStart && "Invalid function pointer");
399 JitSymbolTable **SymTabPtrPtr = 0;
400 #if !ENABLE_JIT_SYMBOL_TABLE
403 SymTabPtrPtr = &__jitSymbolTable;
406 JitSymbolTable *SymTabPtr = *SymTabPtrPtr;
407 JitSymbolEntry *Symbols = SymTabPtr->Symbols;
409 // Scan the table to find its index. The table is not sorted, so do a linear
412 for (Index = 0; Symbols[Index].FnStart != FnStart; ++Index)
413 assert(Index != SymTabPtr->NumSymbols && "Didn't find function!");
415 // Once we have an index, we know to nuke this entry, overwrite it with the
416 // entry at the end of the array, making the last entry redundant.
417 const char *OldName = Symbols[Index].FnName;
418 Symbols[Index] = Symbols[SymTabPtr->NumSymbols-1];
419 free((void*)OldName);
421 // Drop the number of symbols in the table.
422 --SymTabPtr->NumSymbols;
424 // Finally, if we deleted the final symbol, deallocate the table itself.
425 if (SymTabPtr->NumSymbols != 0)
433 //===----------------------------------------------------------------------===//
437 /// JITEmitter - The JIT implementation of the MachineCodeEmitter, which is
438 /// used to output functions to memory for execution.
439 class JITEmitter : public MachineCodeEmitter {
440 JITMemoryManager *MemMgr;
442 // When outputting a function stub in the context of some other function, we
443 // save BufferBegin/BufferEnd/CurBufferPtr here.
444 unsigned char *SavedBufferBegin, *SavedBufferEnd, *SavedCurBufferPtr;
446 /// Relocations - These are the relocations that the function needs, as
448 std::vector<MachineRelocation> Relocations;
450 /// MBBLocations - This vector is a mapping from MBB ID's to their address.
451 /// It is filled in by the StartMachineBasicBlock callback and queried by
452 /// the getMachineBasicBlockAddress callback.
453 std::vector<intptr_t> MBBLocations;
455 /// ConstantPool - The constant pool for the current function.
457 MachineConstantPool *ConstantPool;
459 /// ConstantPoolBase - A pointer to the first entry in the constant pool.
461 void *ConstantPoolBase;
463 /// JumpTable - The jump tables for the current function.
465 MachineJumpTableInfo *JumpTable;
467 /// JumpTableBase - A pointer to the first entry in the jump table.
471 /// Resolver - This contains info about the currently resolved functions.
472 JITResolver Resolver;
474 /// DE - The dwarf emitter for the jit.
477 /// LabelLocations - This vector is a mapping from Label ID's to their
479 std::vector<intptr_t> LabelLocations;
481 /// MMI - Machine module info for exception informations
482 MachineModuleInfo* MMI;
484 // GVSet - a set to keep track of which globals have been seen
485 std::set<const GlobalVariable*> GVSet;
488 JITEmitter(JIT &jit, JITMemoryManager *JMM) : Resolver(jit) {
489 MemMgr = JMM ? JMM : JITMemoryManager::CreateDefaultMemManager();
490 if (jit.getJITInfo().needsGOT()) {
491 MemMgr->AllocateGOT();
492 DOUT << "JIT is managing a GOT\n";
495 if (ExceptionHandling) DE = new JITDwarfEmitter(jit);
499 if (ExceptionHandling) delete DE;
502 /// classof - Methods for support type inquiry through isa, cast, and
505 static inline bool classof(const JITEmitter*) { return true; }
506 static inline bool classof(const MachineCodeEmitter*) { return true; }
508 JITResolver &getJITResolver() { return Resolver; }
510 virtual void startFunction(MachineFunction &F);
511 virtual bool finishFunction(MachineFunction &F);
513 void emitConstantPool(MachineConstantPool *MCP);
514 void initJumpTableInfo(MachineJumpTableInfo *MJTI);
515 void emitJumpTableInfo(MachineJumpTableInfo *MJTI);
517 virtual void startFunctionStub(const GlobalValue* F, unsigned StubSize,
518 unsigned Alignment = 1);
519 virtual void* finishFunctionStub(const GlobalValue *F);
521 /// allocateSpace - Reserves space in the current block if any, or
522 /// allocate a new one of the given size.
523 virtual void *allocateSpace(intptr_t Size, unsigned Alignment);
525 virtual void addRelocation(const MachineRelocation &MR) {
526 Relocations.push_back(MR);
529 virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {
530 if (MBBLocations.size() <= (unsigned)MBB->getNumber())
531 MBBLocations.resize((MBB->getNumber()+1)*2);
532 MBBLocations[MBB->getNumber()] = getCurrentPCValue();
535 virtual intptr_t getConstantPoolEntryAddress(unsigned Entry) const;
536 virtual intptr_t getJumpTableEntryAddress(unsigned Entry) const;
538 virtual intptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const {
539 assert(MBBLocations.size() > (unsigned)MBB->getNumber() &&
540 MBBLocations[MBB->getNumber()] && "MBB not emitted!");
541 return MBBLocations[MBB->getNumber()];
544 /// deallocateMemForFunction - Deallocate all memory for the specified
546 void deallocateMemForFunction(Function *F) {
547 MemMgr->deallocateMemForFunction(F);
550 virtual void emitLabel(uint64_t LabelID) {
551 if (LabelLocations.size() <= LabelID)
552 LabelLocations.resize((LabelID+1)*2);
553 LabelLocations[LabelID] = getCurrentPCValue();
556 virtual intptr_t getLabelAddress(uint64_t LabelID) const {
557 assert(LabelLocations.size() > (unsigned)LabelID &&
558 LabelLocations[LabelID] && "Label not emitted!");
559 return LabelLocations[LabelID];
562 virtual void setModuleInfo(MachineModuleInfo* Info) {
564 if (ExceptionHandling) DE->setModuleInfo(Info);
567 void setMemoryExecutable(void) {
568 MemMgr->setMemoryExecutable();
572 void *getPointerToGlobal(GlobalValue *GV, void *Reference, bool NoNeedStub);
573 void *getPointerToGVLazyPtr(GlobalValue *V, void *Reference,
575 unsigned addSizeOfGlobal(const GlobalVariable *GV, unsigned Size);
576 unsigned addSizeOfGlobalsInConstantVal(const Constant *C, unsigned Size);
577 unsigned addSizeOfGlobalsInInitializer(const Constant *Init, unsigned Size);
578 unsigned GetSizeOfGlobalsInBytes(MachineFunction &MF);
582 void *JITEmitter::getPointerToGlobal(GlobalValue *V, void *Reference,
583 bool DoesntNeedStub) {
584 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) {
585 /// FIXME: If we straightened things out, this could actually emit the
586 /// global immediately instead of queuing it for codegen later!
587 return TheJIT->getOrEmitGlobalVariable(GV);
589 if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
590 return TheJIT->getPointerToGlobal(GA->resolveAliasedGlobal(false));
592 // If we have already compiled the function, return a pointer to its body.
593 Function *F = cast<Function>(V);
594 void *ResultPtr = TheJIT->getPointerToGlobalIfAvailable(F);
595 if (ResultPtr) return ResultPtr;
597 if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode()) {
598 // If this is an external function pointer, we can force the JIT to
599 // 'compile' it, which really just adds it to the map.
601 return TheJIT->getPointerToFunction(F);
603 return Resolver.getFunctionStub(F);
606 // Okay, the function has not been compiled yet, if the target callback
607 // mechanism is capable of rewriting the instruction directly, prefer to do
608 // that instead of emitting a stub.
610 return Resolver.AddCallbackAtLocation(F, Reference);
612 // Otherwise, we have to emit a lazy resolving stub.
613 return Resolver.getFunctionStub(F);
616 void *JITEmitter::getPointerToGVLazyPtr(GlobalValue *V, void *Reference,
617 bool DoesntNeedStub) {
618 // Make sure GV is emitted first.
619 // FIXME: For now, if the GV is an external function we force the JIT to
620 // compile it so the lazy pointer will contain the fully resolved address.
621 void *GVAddress = getPointerToGlobal(V, Reference, true);
622 return Resolver.getGlobalValueLazyPtr(V, GVAddress);
625 static unsigned GetConstantPoolSizeInBytes(MachineConstantPool *MCP) {
626 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
627 if (Constants.empty()) return 0;
629 MachineConstantPoolEntry CPE = Constants.back();
630 unsigned Size = CPE.Offset;
631 const Type *Ty = CPE.isMachineConstantPoolEntry()
632 ? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal->getType();
633 Size += TheJIT->getTargetData()->getABITypeSize(Ty);
637 static unsigned GetJumpTableSizeInBytes(MachineJumpTableInfo *MJTI) {
638 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
639 if (JT.empty()) return 0;
641 unsigned NumEntries = 0;
642 for (unsigned i = 0, e = JT.size(); i != e; ++i)
643 NumEntries += JT[i].MBBs.size();
645 unsigned EntrySize = MJTI->getEntrySize();
647 return NumEntries * EntrySize;
650 static uintptr_t RoundUpToAlign(uintptr_t Size, unsigned Alignment) {
651 if (Alignment == 0) Alignment = 1;
652 // Since we do not know where the buffer will be allocated, be pessimistic.
653 return Size + Alignment;
656 /// addSizeOfGlobal - add the size of the global (plus any alignment padding)
657 /// into the running total Size.
659 unsigned JITEmitter::addSizeOfGlobal(const GlobalVariable *GV, unsigned Size) {
660 const Type *ElTy = GV->getType()->getElementType();
661 size_t GVSize = (size_t)TheJIT->getTargetData()->getABITypeSize(ElTy);
663 (size_t)TheJIT->getTargetData()->getPreferredAlignment(GV);
664 DOUT << "Adding in size " << GVSize << " alignment " << GVAlign;
666 // Assume code section ends with worst possible alignment, so first
667 // variable needs maximal padding.
670 Size = ((Size+GVAlign-1)/GVAlign)*GVAlign;
675 /// addSizeOfGlobalsInConstantVal - find any globals that we haven't seen yet
676 /// but are referenced from the constant; put them in GVSet and add their
677 /// size into the running total Size.
679 unsigned JITEmitter::addSizeOfGlobalsInConstantVal(const Constant *C,
681 // If its undefined, return the garbage.
682 if (isa<UndefValue>(C))
685 // If the value is a ConstantExpr
686 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
687 Constant *Op0 = CE->getOperand(0);
688 switch (CE->getOpcode()) {
689 case Instruction::GetElementPtr:
690 case Instruction::Trunc:
691 case Instruction::ZExt:
692 case Instruction::SExt:
693 case Instruction::FPTrunc:
694 case Instruction::FPExt:
695 case Instruction::UIToFP:
696 case Instruction::SIToFP:
697 case Instruction::FPToUI:
698 case Instruction::FPToSI:
699 case Instruction::PtrToInt:
700 case Instruction::IntToPtr:
701 case Instruction::BitCast: {
702 Size = addSizeOfGlobalsInConstantVal(Op0, Size);
705 case Instruction::Add:
706 case Instruction::Sub:
707 case Instruction::Mul:
708 case Instruction::UDiv:
709 case Instruction::SDiv:
710 case Instruction::URem:
711 case Instruction::SRem:
712 case Instruction::And:
713 case Instruction::Or:
714 case Instruction::Xor: {
715 Size = addSizeOfGlobalsInConstantVal(Op0, Size);
716 Size = addSizeOfGlobalsInConstantVal(CE->getOperand(1), Size);
720 cerr << "ConstantExpr not handled: " << *CE << "\n";
726 if (C->getType()->getTypeID() == Type::PointerTyID)
727 if (const GlobalVariable* GV = dyn_cast<GlobalVariable>(C))
728 if (GVSet.insert(GV).second)
729 Size = addSizeOfGlobal(GV, Size);
734 /// addSizeOfGLobalsInInitializer - handle any globals that we haven't seen yet
735 /// but are referenced from the given initializer.
737 unsigned JITEmitter::addSizeOfGlobalsInInitializer(const Constant *Init,
739 if (!isa<UndefValue>(Init) &&
740 !isa<ConstantVector>(Init) &&
741 !isa<ConstantAggregateZero>(Init) &&
742 !isa<ConstantArray>(Init) &&
743 !isa<ConstantStruct>(Init) &&
744 Init->getType()->isFirstClassType())
745 Size = addSizeOfGlobalsInConstantVal(Init, Size);
749 /// GetSizeOfGlobalsInBytes - walk the code for the function, looking for
750 /// globals; then walk the initializers of those globals looking for more.
751 /// If their size has not been considered yet, add it into the running total
754 unsigned JITEmitter::GetSizeOfGlobalsInBytes(MachineFunction &MF) {
758 for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
760 for (MachineBasicBlock::const_iterator I = MBB->begin(), E = MBB->end();
762 const TargetInstrDesc &Desc = I->getDesc();
763 const MachineInstr &MI = *I;
764 unsigned NumOps = Desc.getNumOperands();
765 for (unsigned CurOp = 0; CurOp < NumOps; CurOp++) {
766 const MachineOperand &MO = MI.getOperand(CurOp);
768 GlobalValue* V = MO.getGlobal();
769 const GlobalVariable *GV = dyn_cast<const GlobalVariable>(V);
772 // If seen in previous function, it will have an entry here.
773 if (TheJIT->getPointerToGlobalIfAvailable(GV))
775 // If seen earlier in this function, it will have an entry here.
776 // FIXME: it should be possible to combine these tables, by
777 // assuming the addresses of the new globals in this module
778 // start at 0 (or something) and adjusting them after codegen
779 // complete. Another possibility is to grab a marker bit in GV.
780 if (GVSet.insert(GV).second)
781 // A variable as yet unseen. Add in its size.
782 Size = addSizeOfGlobal(GV, Size);
787 DOUT << "About to look through initializers\n";
788 // Look for more globals that are referenced only from initializers.
789 // GVSet.end is computed each time because the set can grow as we go.
790 for (std::set<const GlobalVariable *>::iterator I = GVSet.begin();
791 I != GVSet.end(); I++) {
792 const GlobalVariable* GV = *I;
793 if (GV->hasInitializer())
794 Size = addSizeOfGlobalsInInitializer(GV->getInitializer(), Size);
800 void JITEmitter::startFunction(MachineFunction &F) {
801 uintptr_t ActualSize = 0;
802 // Set the memory writable, if it's not already
803 MemMgr->setMemoryWritable();
804 if (MemMgr->NeedsExactSize()) {
805 DOUT << "ExactSize\n";
806 const TargetInstrInfo* TII = F.getTarget().getInstrInfo();
807 MachineJumpTableInfo *MJTI = F.getJumpTableInfo();
808 MachineConstantPool *MCP = F.getConstantPool();
810 // Ensure the constant pool/jump table info is at least 4-byte aligned.
811 ActualSize = RoundUpToAlign(ActualSize, 16);
813 // Add the alignment of the constant pool
814 ActualSize = RoundUpToAlign(ActualSize,
815 1 << MCP->getConstantPoolAlignment());
817 // Add the constant pool size
818 ActualSize += GetConstantPoolSizeInBytes(MCP);
820 // Add the aligment of the jump table info
821 ActualSize = RoundUpToAlign(ActualSize, MJTI->getAlignment());
823 // Add the jump table size
824 ActualSize += GetJumpTableSizeInBytes(MJTI);
826 // Add the alignment for the function
827 ActualSize = RoundUpToAlign(ActualSize,
828 std::max(F.getFunction()->getAlignment(), 8U));
830 // Add the function size
831 ActualSize += TII->GetFunctionSizeInBytes(F);
833 DOUT << "ActualSize before globals " << ActualSize << "\n";
834 // Add the size of the globals that will be allocated after this function.
835 // These are all the ones referenced from this function that were not
836 // previously allocated.
837 ActualSize += GetSizeOfGlobalsInBytes(F);
838 DOUT << "ActualSize after globals " << ActualSize << "\n";
841 BufferBegin = CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(),
843 BufferEnd = BufferBegin+ActualSize;
845 // Ensure the constant pool/jump table info is at least 4-byte aligned.
848 emitConstantPool(F.getConstantPool());
849 initJumpTableInfo(F.getJumpTableInfo());
851 // About to start emitting the machine code for the function.
852 emitAlignment(std::max(F.getFunction()->getAlignment(), 8U));
853 TheJIT->updateGlobalMapping(F.getFunction(), CurBufferPtr);
855 MBBLocations.clear();
858 bool JITEmitter::finishFunction(MachineFunction &F) {
859 if (CurBufferPtr == BufferEnd) {
860 // FIXME: Allocate more space, then try again.
861 cerr << "JIT: Ran out of space for generated machine code!\n";
865 emitJumpTableInfo(F.getJumpTableInfo());
867 // FnStart is the start of the text, not the start of the constant pool and
868 // other per-function data.
869 unsigned char *FnStart =
870 (unsigned char *)TheJIT->getPointerToGlobalIfAvailable(F.getFunction());
872 if (!Relocations.empty()) {
873 NumRelos += Relocations.size();
875 // Resolve the relocations to concrete pointers.
876 for (unsigned i = 0, e = Relocations.size(); i != e; ++i) {
877 MachineRelocation &MR = Relocations[i];
879 if (!MR.letTargetResolve()) {
881 ResultPtr = TheJIT->getPointerToNamedFunction(MR.getString());
883 // If the target REALLY wants a stub for this function, emit it now.
884 if (!MR.doesntNeedStub())
885 ResultPtr = Resolver.getExternalFunctionStub(ResultPtr);
886 } else if (MR.isGlobalValue()) {
887 ResultPtr = getPointerToGlobal(MR.getGlobalValue(),
888 BufferBegin+MR.getMachineCodeOffset(),
889 MR.doesntNeedStub());
890 } else if (MR.isGlobalValueLazyPtr()) {
891 ResultPtr = getPointerToGVLazyPtr(MR.getGlobalValue(),
892 BufferBegin+MR.getMachineCodeOffset(),
893 MR.doesntNeedStub());
894 } else if (MR.isBasicBlock()) {
895 ResultPtr = (void*)getMachineBasicBlockAddress(MR.getBasicBlock());
896 } else if (MR.isConstantPoolIndex()) {
897 ResultPtr = (void*)getConstantPoolEntryAddress(MR.getConstantPoolIndex());
899 assert(MR.isJumpTableIndex());
900 ResultPtr=(void*)getJumpTableEntryAddress(MR.getJumpTableIndex());
903 MR.setResultPointer(ResultPtr);
906 // if we are managing the GOT and the relocation wants an index,
908 if (MR.isGOTRelative() && MemMgr->isManagingGOT()) {
909 unsigned idx = Resolver.getGOTIndexForAddr(ResultPtr);
911 if (((void**)MemMgr->getGOTBase())[idx] != ResultPtr) {
912 DOUT << "GOT was out of date for " << ResultPtr
913 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx]
915 ((void**)MemMgr->getGOTBase())[idx] = ResultPtr;
920 TheJIT->getJITInfo().relocate(BufferBegin, &Relocations[0],
921 Relocations.size(), MemMgr->getGOTBase());
924 // Update the GOT entry for F to point to the new code.
925 if (MemMgr->isManagingGOT()) {
926 unsigned idx = Resolver.getGOTIndexForAddr((void*)BufferBegin);
927 if (((void**)MemMgr->getGOTBase())[idx] != (void*)BufferBegin) {
928 DOUT << "GOT was out of date for " << (void*)BufferBegin
929 << " pointing at " << ((void**)MemMgr->getGOTBase())[idx] << "\n";
930 ((void**)MemMgr->getGOTBase())[idx] = (void*)BufferBegin;
934 unsigned char *FnEnd = CurBufferPtr;
936 MemMgr->endFunctionBody(F.getFunction(), BufferBegin, FnEnd);
937 BufferBegin = CurBufferPtr = 0;
938 NumBytes += FnEnd-FnStart;
940 // Invalidate the icache if necessary.
941 sys::Memory::InvalidateInstructionCache(FnStart, FnEnd-FnStart);
943 // Add it to the JIT symbol table if the host wants it.
944 AddFunctionToSymbolTable(F.getFunction()->getNameStart(),
945 FnStart, FnEnd-FnStart);
947 DOUT << "JIT: Finished CodeGen of [" << (void*)FnStart
948 << "] Function: " << F.getFunction()->getName()
949 << ": " << (FnEnd-FnStart) << " bytes of text, "
950 << Relocations.size() << " relocations\n";
953 // Mark code region readable and executable if it's not so already.
954 MemMgr->setMemoryExecutable();
960 unsigned char* q = FnStart;
961 for (i=1; q!=FnEnd; q++, i++) {
963 DOUT << "0x" << (long)q << ": ";
964 DOUT<< (unsigned short)*q << " ";
969 if (sys::hasDisassembler())
970 DOUT << "Disassembled code:\n"
971 << sys::disassembleBuffer(FnStart, FnEnd-FnStart, (uintptr_t)FnStart);
974 if (ExceptionHandling) {
975 uintptr_t ActualSize = 0;
976 SavedBufferBegin = BufferBegin;
977 SavedBufferEnd = BufferEnd;
978 SavedCurBufferPtr = CurBufferPtr;
980 if (MemMgr->NeedsExactSize()) {
981 ActualSize = DE->GetDwarfTableSizeInBytes(F, *this, FnStart, FnEnd);
984 BufferBegin = CurBufferPtr = MemMgr->startExceptionTable(F.getFunction(),
986 BufferEnd = BufferBegin+ActualSize;
987 unsigned char* FrameRegister = DE->EmitDwarfTable(F, *this, FnStart, FnEnd);
988 MemMgr->endExceptionTable(F.getFunction(), BufferBegin, CurBufferPtr,
990 BufferBegin = SavedBufferBegin;
991 BufferEnd = SavedBufferEnd;
992 CurBufferPtr = SavedCurBufferPtr;
994 TheJIT->RegisterTable(FrameRegister);
1003 void* JITEmitter::allocateSpace(intptr_t Size, unsigned Alignment) {
1005 return MachineCodeEmitter::allocateSpace(Size, Alignment);
1007 // create a new memory block if there is no active one.
1008 // care must be taken so that BufferBegin is invalidated when a
1010 BufferBegin = CurBufferPtr = MemMgr->allocateSpace(Size, Alignment);
1011 BufferEnd = BufferBegin+Size;
1012 return CurBufferPtr;
1015 void JITEmitter::emitConstantPool(MachineConstantPool *MCP) {
1016 if (TheJIT->getJITInfo().hasCustomConstantPool()) {
1017 DOUT << "JIT: Target has custom constant pool handling. Omitting standard "
1021 const std::vector<MachineConstantPoolEntry> &Constants = MCP->getConstants();
1022 if (Constants.empty()) return;
1024 MachineConstantPoolEntry CPE = Constants.back();
1025 unsigned Size = CPE.Offset;
1026 const Type *Ty = CPE.isMachineConstantPoolEntry()
1027 ? CPE.Val.MachineCPVal->getType() : CPE.Val.ConstVal->getType();
1028 Size += TheJIT->getTargetData()->getABITypeSize(Ty);
1030 unsigned Align = 1 << MCP->getConstantPoolAlignment();
1031 ConstantPoolBase = allocateSpace(Size, Align);
1034 if (ConstantPoolBase == 0) return; // Buffer overflow.
1036 DOUT << "JIT: Emitted constant pool at [" << ConstantPoolBase
1037 << "] (size: " << Size << ", alignment: " << Align << ")\n";
1039 // Initialize the memory for all of the constant pool entries.
1040 for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
1041 void *CAddr = (char*)ConstantPoolBase+Constants[i].Offset;
1042 if (Constants[i].isMachineConstantPoolEntry()) {
1043 // FIXME: add support to lower machine constant pool values into bytes!
1044 cerr << "Initialize memory with machine specific constant pool entry"
1045 << " has not been implemented!\n";
1048 TheJIT->InitializeMemory(Constants[i].Val.ConstVal, CAddr);
1049 DOUT << "JIT: CP" << i << " at [" << CAddr << "]\n";
1053 void JITEmitter::initJumpTableInfo(MachineJumpTableInfo *MJTI) {
1054 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1055 if (JT.empty()) return;
1057 unsigned NumEntries = 0;
1058 for (unsigned i = 0, e = JT.size(); i != e; ++i)
1059 NumEntries += JT[i].MBBs.size();
1061 unsigned EntrySize = MJTI->getEntrySize();
1063 // Just allocate space for all the jump tables now. We will fix up the actual
1064 // MBB entries in the tables after we emit the code for each block, since then
1065 // we will know the final locations of the MBBs in memory.
1067 JumpTableBase = allocateSpace(NumEntries * EntrySize, MJTI->getAlignment());
1070 void JITEmitter::emitJumpTableInfo(MachineJumpTableInfo *MJTI) {
1071 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1072 if (JT.empty() || JumpTableBase == 0) return;
1074 if (TargetMachine::getRelocationModel() == Reloc::PIC_) {
1075 assert(MJTI->getEntrySize() == 4 && "Cross JIT'ing?");
1076 // For each jump table, place the offset from the beginning of the table
1077 // to the target address.
1078 int *SlotPtr = (int*)JumpTableBase;
1080 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1081 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1082 // Store the offset of the basic block for this jump table slot in the
1083 // memory we allocated for the jump table in 'initJumpTableInfo'
1084 intptr_t Base = (intptr_t)SlotPtr;
1085 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) {
1086 intptr_t MBBAddr = getMachineBasicBlockAddress(MBBs[mi]);
1087 *SlotPtr++ = TheJIT->getJITInfo().getPICJumpTableEntry(MBBAddr, Base);
1091 assert(MJTI->getEntrySize() == sizeof(void*) && "Cross JIT'ing?");
1093 // For each jump table, map each target in the jump table to the address of
1094 // an emitted MachineBasicBlock.
1095 intptr_t *SlotPtr = (intptr_t*)JumpTableBase;
1097 for (unsigned i = 0, e = JT.size(); i != e; ++i) {
1098 const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
1099 // Store the address of the basic block for this jump table slot in the
1100 // memory we allocated for the jump table in 'initJumpTableInfo'
1101 for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi)
1102 *SlotPtr++ = getMachineBasicBlockAddress(MBBs[mi]);
1107 void JITEmitter::startFunctionStub(const GlobalValue* F, unsigned StubSize,
1108 unsigned Alignment) {
1109 SavedBufferBegin = BufferBegin;
1110 SavedBufferEnd = BufferEnd;
1111 SavedCurBufferPtr = CurBufferPtr;
1113 BufferBegin = CurBufferPtr = MemMgr->allocateStub(F, StubSize, Alignment);
1114 BufferEnd = BufferBegin+StubSize+1;
1117 void *JITEmitter::finishFunctionStub(const GlobalValue* F) {
1118 NumBytes += getCurrentPCOffset();
1120 // Invalidate the icache if necessary.
1121 sys::Memory::InvalidateInstructionCache(BufferBegin, NumBytes);
1123 std::swap(SavedBufferBegin, BufferBegin);
1124 BufferEnd = SavedBufferEnd;
1125 CurBufferPtr = SavedCurBufferPtr;
1126 return SavedBufferBegin;
1129 // getConstantPoolEntryAddress - Return the address of the 'ConstantNum' entry
1130 // in the constant pool that was last emitted with the 'emitConstantPool'
1133 intptr_t JITEmitter::getConstantPoolEntryAddress(unsigned ConstantNum) const {
1134 assert(ConstantNum < ConstantPool->getConstants().size() &&
1135 "Invalid ConstantPoolIndex!");
1136 return (intptr_t)ConstantPoolBase +
1137 ConstantPool->getConstants()[ConstantNum].Offset;
1140 // getJumpTableEntryAddress - Return the address of the JumpTable with index
1141 // 'Index' in the jumpp table that was last initialized with 'initJumpTableInfo'
1143 intptr_t JITEmitter::getJumpTableEntryAddress(unsigned Index) const {
1144 const std::vector<MachineJumpTableEntry> &JT = JumpTable->getJumpTables();
1145 assert(Index < JT.size() && "Invalid jump table index!");
1147 unsigned Offset = 0;
1148 unsigned EntrySize = JumpTable->getEntrySize();
1150 for (unsigned i = 0; i < Index; ++i)
1151 Offset += JT[i].MBBs.size();
1153 Offset *= EntrySize;
1155 return (intptr_t)((char *)JumpTableBase + Offset);
1158 //===----------------------------------------------------------------------===//
1159 // Public interface to this file
1160 //===----------------------------------------------------------------------===//
1162 MachineCodeEmitter *JIT::createEmitter(JIT &jit, JITMemoryManager *JMM) {
1163 return new JITEmitter(jit, JMM);
1166 // getPointerToNamedFunction - This function is used as a global wrapper to
1167 // JIT::getPointerToNamedFunction for the purpose of resolving symbols when
1168 // bugpoint is debugging the JIT. In that scenario, we are loading an .so and
1169 // need to resolve function(s) that are being mis-codegenerated, so we need to
1170 // resolve their addresses at runtime, and this is the way to do it.
1172 void *getPointerToNamedFunction(const char *Name) {
1173 if (Function *F = TheJIT->FindFunctionNamed(Name))
1174 return TheJIT->getPointerToFunction(F);
1175 return TheJIT->getPointerToNamedFunction(Name);
1179 // getPointerToFunctionOrStub - If the specified function has been
1180 // code-gen'd, return a pointer to the function. If not, compile it, or use
1181 // a stub to implement lazy compilation if available.
1183 void *JIT::getPointerToFunctionOrStub(Function *F) {
1184 // If we have already code generated the function, just return the address.
1185 if (void *Addr = getPointerToGlobalIfAvailable(F))
1188 // Get a stub if the target supports it.
1189 assert(isa<JITEmitter>(MCE) && "Unexpected MCE?");
1190 JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());
1191 return JE->getJITResolver().getFunctionStub(F);
1194 /// freeMachineCodeForFunction - release machine code memory for given Function.
1196 void JIT::freeMachineCodeForFunction(Function *F) {
1198 // Delete translation for this from the ExecutionEngine, so it will get
1199 // retranslated next time it is used.
1200 void *OldPtr = updateGlobalMapping(F, 0);
1203 RemoveFunctionFromSymbolTable(OldPtr);
1205 // Free the actual memory for the function body and related stuff.
1206 assert(isa<JITEmitter>(MCE) && "Unexpected MCE?");
1207 cast<JITEmitter>(MCE)->deallocateMemForFunction(F);