• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 //===-- JIT.cpp - LLVM Just in Time Compiler ------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This tool implements a just-in-time compiler for LLVM, allowing direct
11 // execution of LLVM bitcode in an efficient manner.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "JIT.h"
16 #include "llvm/Constants.h"
17 #include "llvm/DerivedTypes.h"
18 #include "llvm/Function.h"
19 #include "llvm/GlobalVariable.h"
20 #include "llvm/Instructions.h"
21 #include "llvm/ADT/SmallPtrSet.h"
22 #include "llvm/CodeGen/JITCodeEmitter.h"
23 #include "llvm/CodeGen/MachineCodeInfo.h"
24 #include "llvm/ExecutionEngine/GenericValue.h"
25 #include "llvm/ExecutionEngine/JITEventListener.h"
26 #include "llvm/Target/TargetData.h"
27 #include "llvm/Target/TargetMachine.h"
28 #include "llvm/Target/TargetJITInfo.h"
29 #include "llvm/Support/Dwarf.h"
30 #include "llvm/Support/ErrorHandling.h"
31 #include "llvm/Support/ManagedStatic.h"
32 #include "llvm/Support/MutexGuard.h"
33 #include "llvm/Support/DynamicLibrary.h"
34 #include "llvm/Config/config.h"
35 
36 using namespace llvm;
37 
38 #ifdef __APPLE__
39 // Apple gcc defaults to -fuse-cxa-atexit (i.e. calls __cxa_atexit instead
40 // of atexit). It passes the address of linker generated symbol __dso_handle
41 // to the function.
42 // This configuration change happened at version 5330.
43 # include <AvailabilityMacros.h>
44 # if defined(MAC_OS_X_VERSION_10_4) && \
45      ((MAC_OS_X_VERSION_MIN_REQUIRED > MAC_OS_X_VERSION_10_4) || \
46       (MAC_OS_X_VERSION_MIN_REQUIRED == MAC_OS_X_VERSION_10_4 && \
47        __APPLE_CC__ >= 5330))
48 #  ifndef HAVE___DSO_HANDLE
49 #   define HAVE___DSO_HANDLE 1
50 #  endif
51 # endif
52 #endif
53 
54 #if HAVE___DSO_HANDLE
55 extern void *__dso_handle __attribute__ ((__visibility__ ("hidden")));
56 #endif
57 
58 namespace {
59 
60 static struct RegisterJIT {
RegisterJIT__anonc3ed9af30111::RegisterJIT61   RegisterJIT() { JIT::Register(); }
62 } JITRegistrator;
63 
64 }
65 
LLVMLinkInJIT()66 extern "C" void LLVMLinkInJIT() {
67 }
68 
69 // Determine whether we can register EH tables.
70 #if (defined(__GNUC__) && !defined(__ARM_EABI__) && \
71      !defined(__USING_SJLJ_EXCEPTIONS__))
72 #define HAVE_EHTABLE_SUPPORT 1
73 #else
74 #define HAVE_EHTABLE_SUPPORT 0
75 #endif
76 
77 #if HAVE_EHTABLE_SUPPORT
78 
79 // libgcc defines the __register_frame function to dynamically register new
80 // dwarf frames for exception handling. This functionality is not portable
81 // across compilers and is only provided by GCC. We use the __register_frame
82 // function here so that code generated by the JIT cooperates with the unwinding
83 // runtime of libgcc. When JITting with exception handling enable, LLVM
84 // generates dwarf frames and registers it to libgcc with __register_frame.
85 //
86 // The __register_frame function works with Linux.
87 //
88 // Unfortunately, this functionality seems to be in libgcc after the unwinding
89 // library of libgcc for darwin was written. The code for darwin overwrites the
90 // value updated by __register_frame with a value fetched with "keymgr".
91 // "keymgr" is an obsolete functionality, which should be rewritten some day.
92 // In the meantime, since "keymgr" is on all libgccs shipped with apple-gcc, we
93 // need a workaround in LLVM which uses the "keymgr" to dynamically modify the
94 // values of an opaque key, used by libgcc to find dwarf tables.
95 
96 extern "C" void __register_frame(void*);
97 extern "C" void __deregister_frame(void*);
98 
99 #if defined(__APPLE__) && MAC_OS_X_VERSION_MAX_ALLOWED <= 1050
100 # define USE_KEYMGR 1
101 #else
102 # define USE_KEYMGR 0
103 #endif
104 
105 #if USE_KEYMGR
106 
107 namespace {
108 
109 // LibgccObject - This is the structure defined in libgcc. There is no #include
110 // provided for this structure, so we also define it here. libgcc calls it
111 // "struct object". The structure is undocumented in libgcc.
112 struct LibgccObject {
113   void *unused1;
114   void *unused2;
115   void *unused3;
116 
117   /// frame - Pointer to the exception table.
118   void *frame;
119 
120   /// encoding -  The encoding of the object?
121   union {
122     struct {
123       unsigned long sorted : 1;
124       unsigned long from_array : 1;
125       unsigned long mixed_encoding : 1;
126       unsigned long encoding : 8;
127       unsigned long count : 21;
128     } b;
129     size_t i;
130   } encoding;
131 
132   /// fde_end - libgcc defines this field only if some macro is defined. We
133   /// include this field even if it may not there, to make libgcc happy.
134   char *fde_end;
135 
136   /// next - At least we know it's a chained list!
137   struct LibgccObject *next;
138 };
139 
140 // "kemgr" stuff. Apparently, all frame tables are stored there.
141 extern "C" void _keymgr_set_and_unlock_processwide_ptr(int, void *);
142 extern "C" void *_keymgr_get_and_lock_processwide_ptr(int);
143 #define KEYMGR_GCC3_DW2_OBJ_LIST        302     /* Dwarf2 object list  */
144 
145 /// LibgccObjectInfo - libgcc defines this struct as km_object_info. It
146 /// probably contains all dwarf tables that are loaded.
147 struct LibgccObjectInfo {
148 
149   /// seenObjects - LibgccObjects already parsed by the unwinding runtime.
150   ///
151   struct LibgccObject* seenObjects;
152 
153   /// unseenObjects - LibgccObjects not parsed yet by the unwinding runtime.
154   ///
155   struct LibgccObject* unseenObjects;
156 
157   unsigned unused[2];
158 };
159 
160 /// darwin_register_frame - Since __register_frame does not work with darwin's
161 /// libgcc,we provide our own function, which "tricks" libgcc by modifying the
162 /// "Dwarf2 object list" key.
DarwinRegisterFrame(void * FrameBegin)163 void DarwinRegisterFrame(void* FrameBegin) {
164   // Get the key.
165   LibgccObjectInfo* LOI = (struct LibgccObjectInfo*)
166     _keymgr_get_and_lock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST);
167   assert(LOI && "This should be preallocated by the runtime");
168 
169   // Allocate a new LibgccObject to represent this frame. Deallocation of this
170   // object may be impossible: since darwin code in libgcc was written after
171   // the ability to dynamically register frames, things may crash if we
172   // deallocate it.
173   struct LibgccObject* ob = (struct LibgccObject*)
174     malloc(sizeof(struct LibgccObject));
175 
176   // Do like libgcc for the values of the field.
177   ob->unused1 = (void *)-1;
178   ob->unused2 = 0;
179   ob->unused3 = 0;
180   ob->frame = FrameBegin;
181   ob->encoding.i = 0;
182   ob->encoding.b.encoding = llvm::dwarf::DW_EH_PE_omit;
183 
184   // Put the info on both places, as libgcc uses the first or the second
185   // field. Note that we rely on having two pointers here. If fde_end was a
186   // char, things would get complicated.
187   ob->fde_end = (char*)LOI->unseenObjects;
188   ob->next = LOI->unseenObjects;
189 
190   // Update the key's unseenObjects list.
191   LOI->unseenObjects = ob;
192 
193   // Finally update the "key". Apparently, libgcc requires it.
194   _keymgr_set_and_unlock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST,
195                                          LOI);
196 
197 }
198 
199 }
200 #endif // __APPLE__
201 #endif // HAVE_EHTABLE_SUPPORT
202 
203 /// createJIT - This is the factory method for creating a JIT for the current
204 /// machine, it does not fall back to the interpreter.  This takes ownership
205 /// of the module.
createJIT(Module * M,std::string * ErrorStr,JITMemoryManager * JMM,CodeGenOpt::Level OptLevel,bool GVsWithCode,TargetMachine * TM)206 ExecutionEngine *JIT::createJIT(Module *M,
207                                 std::string *ErrorStr,
208                                 JITMemoryManager *JMM,
209                                 CodeGenOpt::Level OptLevel,
210                                 bool GVsWithCode,
211                                 TargetMachine *TM) {
212   // Try to register the program as a source of symbols to resolve against.
213   //
214   // FIXME: Don't do this here.
215   sys::DynamicLibrary::LoadLibraryPermanently(0, NULL);
216 
217   // If the target supports JIT code generation, create the JIT.
218   if (TargetJITInfo *TJ = TM->getJITInfo()) {
219     return new JIT(M, *TM, *TJ, JMM, OptLevel, GVsWithCode);
220   } else {
221     if (ErrorStr)
222       *ErrorStr = "target does not support JIT code generation";
223     return 0;
224   }
225 }
226 
227 namespace {
228 /// This class supports the global getPointerToNamedFunction(), which allows
229 /// bugpoint or gdb users to search for a function by name without any context.
230 class JitPool {
231   SmallPtrSet<JIT*, 1> JITs;  // Optimize for process containing just 1 JIT.
232   mutable sys::Mutex Lock;
233 public:
Add(JIT * jit)234   void Add(JIT *jit) {
235     MutexGuard guard(Lock);
236     JITs.insert(jit);
237   }
Remove(JIT * jit)238   void Remove(JIT *jit) {
239     MutexGuard guard(Lock);
240     JITs.erase(jit);
241   }
getPointerToNamedFunction(const char * Name) const242   void *getPointerToNamedFunction(const char *Name) const {
243     MutexGuard guard(Lock);
244     assert(JITs.size() != 0 && "No Jit registered");
245     //search function in every instance of JIT
246     for (SmallPtrSet<JIT*, 1>::const_iterator Jit = JITs.begin(),
247            end = JITs.end();
248          Jit != end; ++Jit) {
249       if (Function *F = (*Jit)->FindFunctionNamed(Name))
250         return (*Jit)->getPointerToFunction(F);
251     }
252     // The function is not available : fallback on the first created (will
253     // search in symbol of the current program/library)
254     return (*JITs.begin())->getPointerToNamedFunction(Name);
255   }
256 };
257 ManagedStatic<JitPool> AllJits;
258 }
259 extern "C" {
260   // getPointerToNamedFunction - This function is used as a global wrapper to
261   // JIT::getPointerToNamedFunction for the purpose of resolving symbols when
262   // bugpoint is debugging the JIT. In that scenario, we are loading an .so and
263   // need to resolve function(s) that are being mis-codegenerated, so we need to
264   // resolve their addresses at runtime, and this is the way to do it.
getPointerToNamedFunction(const char * Name)265   void *getPointerToNamedFunction(const char *Name) {
266     return AllJits->getPointerToNamedFunction(Name);
267   }
268 }
269 
JIT(Module * M,TargetMachine & tm,TargetJITInfo & tji,JITMemoryManager * JMM,CodeGenOpt::Level OptLevel,bool GVsWithCode)270 JIT::JIT(Module *M, TargetMachine &tm, TargetJITInfo &tji,
271          JITMemoryManager *JMM, CodeGenOpt::Level OptLevel, bool GVsWithCode)
272   : ExecutionEngine(M), TM(tm), TJI(tji), AllocateGVsWithCode(GVsWithCode),
273     isAlreadyCodeGenerating(false) {
274   setTargetData(TM.getTargetData());
275 
276   jitstate = new JITState(M);
277 
278   // Initialize JCE
279   JCE = createEmitter(*this, JMM, TM);
280 
281   // Register in global list of all JITs.
282   AllJits->Add(this);
283 
284   // Add target data
285   MutexGuard locked(lock);
286   FunctionPassManager &PM = jitstate->getPM(locked);
287   PM.add(new TargetData(*TM.getTargetData()));
288 
289   // Turn the machine code intermediate representation into bytes in memory that
290   // may be executed.
291   if (TM.addPassesToEmitMachineCode(PM, *JCE, OptLevel)) {
292     report_fatal_error("Target does not support machine code emission!");
293   }
294 
295   // Register routine for informing unwinding runtime about new EH frames
296 #if HAVE_EHTABLE_SUPPORT
297 #if USE_KEYMGR
298   struct LibgccObjectInfo* LOI = (struct LibgccObjectInfo*)
299     _keymgr_get_and_lock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST);
300 
301   // The key is created on demand, and libgcc creates it the first time an
302   // exception occurs. Since we need the key to register frames, we create
303   // it now.
304   if (!LOI)
305     LOI = (LibgccObjectInfo*)calloc(sizeof(struct LibgccObjectInfo), 1);
306   _keymgr_set_and_unlock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST, LOI);
307   InstallExceptionTableRegister(DarwinRegisterFrame);
308   // Not sure about how to deregister on Darwin.
309 #else
310   InstallExceptionTableRegister(__register_frame);
311   InstallExceptionTableDeregister(__deregister_frame);
312 #endif // __APPLE__
313 #endif // HAVE_EHTABLE_SUPPORT
314 
315   // Initialize passes.
316   PM.doInitialization();
317 }
318 
~JIT()319 JIT::~JIT() {
320   // Unregister all exception tables registered by this JIT.
321   DeregisterAllTables();
322   // Cleanup.
323   AllJits->Remove(this);
324   delete jitstate;
325   delete JCE;
326   delete &TM;
327 }
328 
329 /// addModule - Add a new Module to the JIT.  If we previously removed the last
330 /// Module, we need re-initialize jitstate with a valid Module.
addModule(Module * M)331 void JIT::addModule(Module *M) {
332   MutexGuard locked(lock);
333 
334   if (Modules.empty()) {
335     assert(!jitstate && "jitstate should be NULL if Modules vector is empty!");
336 
337     jitstate = new JITState(M);
338 
339     FunctionPassManager &PM = jitstate->getPM(locked);
340     PM.add(new TargetData(*TM.getTargetData()));
341 
342     // Turn the machine code intermediate representation into bytes in memory
343     // that may be executed.
344     if (TM.addPassesToEmitMachineCode(PM, *JCE, CodeGenOpt::Default)) {
345       report_fatal_error("Target does not support machine code emission!");
346     }
347 
348     // Initialize passes.
349     PM.doInitialization();
350   }
351 
352   ExecutionEngine::addModule(M);
353 }
354 
355 /// removeModule - If we are removing the last Module, invalidate the jitstate
356 /// since the PassManager it contains references a released Module.
removeModule(Module * M)357 bool JIT::removeModule(Module *M) {
358   bool result = ExecutionEngine::removeModule(M);
359 
360   MutexGuard locked(lock);
361 
362   if (jitstate->getModule() == M) {
363     delete jitstate;
364     jitstate = 0;
365   }
366 
367   if (!jitstate && !Modules.empty()) {
368     jitstate = new JITState(Modules[0]);
369 
370     FunctionPassManager &PM = jitstate->getPM(locked);
371     PM.add(new TargetData(*TM.getTargetData()));
372 
373     // Turn the machine code intermediate representation into bytes in memory
374     // that may be executed.
375     if (TM.addPassesToEmitMachineCode(PM, *JCE, CodeGenOpt::Default)) {
376       report_fatal_error("Target does not support machine code emission!");
377     }
378 
379     // Initialize passes.
380     PM.doInitialization();
381   }
382   return result;
383 }
384 
385 /// run - Start execution with the specified function and arguments.
386 ///
runFunction(Function * F,const std::vector<GenericValue> & ArgValues)387 GenericValue JIT::runFunction(Function *F,
388                               const std::vector<GenericValue> &ArgValues) {
389   assert(F && "Function *F was null at entry to run()");
390 
391   void *FPtr = getPointerToFunction(F);
392   assert(FPtr && "Pointer to fn's code was null after getPointerToFunction");
393   FunctionType *FTy = F->getFunctionType();
394   Type *RetTy = FTy->getReturnType();
395 
396   assert((FTy->getNumParams() == ArgValues.size() ||
397           (FTy->isVarArg() && FTy->getNumParams() <= ArgValues.size())) &&
398          "Wrong number of arguments passed into function!");
399   assert(FTy->getNumParams() == ArgValues.size() &&
400          "This doesn't support passing arguments through varargs (yet)!");
401 
402   // Handle some common cases first.  These cases correspond to common `main'
403   // prototypes.
404   if (RetTy->isIntegerTy(32) || RetTy->isVoidTy()) {
405     switch (ArgValues.size()) {
406     case 3:
407       if (FTy->getParamType(0)->isIntegerTy(32) &&
408           FTy->getParamType(1)->isPointerTy() &&
409           FTy->getParamType(2)->isPointerTy()) {
410         int (*PF)(int, char **, const char **) =
411           (int(*)(int, char **, const char **))(intptr_t)FPtr;
412 
413         // Call the function.
414         GenericValue rv;
415         rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
416                                  (char **)GVTOP(ArgValues[1]),
417                                  (const char **)GVTOP(ArgValues[2])));
418         return rv;
419       }
420       break;
421     case 2:
422       if (FTy->getParamType(0)->isIntegerTy(32) &&
423           FTy->getParamType(1)->isPointerTy()) {
424         int (*PF)(int, char **) = (int(*)(int, char **))(intptr_t)FPtr;
425 
426         // Call the function.
427         GenericValue rv;
428         rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
429                                  (char **)GVTOP(ArgValues[1])));
430         return rv;
431       }
432       break;
433     case 1:
434       if (FTy->getNumParams() == 1 &&
435           FTy->getParamType(0)->isIntegerTy(32)) {
436         GenericValue rv;
437         int (*PF)(int) = (int(*)(int))(intptr_t)FPtr;
438         rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue()));
439         return rv;
440       }
441       break;
442     }
443   }
444 
445   // Handle cases where no arguments are passed first.
446   if (ArgValues.empty()) {
447     GenericValue rv;
448     switch (RetTy->getTypeID()) {
449     default: llvm_unreachable("Unknown return type for function call!");
450     case Type::IntegerTyID: {
451       unsigned BitWidth = cast<IntegerType>(RetTy)->getBitWidth();
452       if (BitWidth == 1)
453         rv.IntVal = APInt(BitWidth, ((bool(*)())(intptr_t)FPtr)());
454       else if (BitWidth <= 8)
455         rv.IntVal = APInt(BitWidth, ((char(*)())(intptr_t)FPtr)());
456       else if (BitWidth <= 16)
457         rv.IntVal = APInt(BitWidth, ((short(*)())(intptr_t)FPtr)());
458       else if (BitWidth <= 32)
459         rv.IntVal = APInt(BitWidth, ((int(*)())(intptr_t)FPtr)());
460       else if (BitWidth <= 64)
461         rv.IntVal = APInt(BitWidth, ((int64_t(*)())(intptr_t)FPtr)());
462       else
463         llvm_unreachable("Integer types > 64 bits not supported");
464       return rv;
465     }
466     case Type::VoidTyID:
467       rv.IntVal = APInt(32, ((int(*)())(intptr_t)FPtr)());
468       return rv;
469     case Type::FloatTyID:
470       rv.FloatVal = ((float(*)())(intptr_t)FPtr)();
471       return rv;
472     case Type::DoubleTyID:
473       rv.DoubleVal = ((double(*)())(intptr_t)FPtr)();
474       return rv;
475     case Type::X86_FP80TyID:
476     case Type::FP128TyID:
477     case Type::PPC_FP128TyID:
478       llvm_unreachable("long double not supported yet");
479       return rv;
480     case Type::PointerTyID:
481       return PTOGV(((void*(*)())(intptr_t)FPtr)());
482     }
483   }
484 
485   // Okay, this is not one of our quick and easy cases.  Because we don't have a
486   // full FFI, we have to codegen a nullary stub function that just calls the
487   // function we are interested in, passing in constants for all of the
488   // arguments.  Make this function and return.
489 
490   // First, create the function.
491   FunctionType *STy=FunctionType::get(RetTy, false);
492   Function *Stub = Function::Create(STy, Function::InternalLinkage, "",
493                                     F->getParent());
494 
495   // Insert a basic block.
496   BasicBlock *StubBB = BasicBlock::Create(F->getContext(), "", Stub);
497 
498   // Convert all of the GenericValue arguments over to constants.  Note that we
499   // currently don't support varargs.
500   SmallVector<Value*, 8> Args;
501   for (unsigned i = 0, e = ArgValues.size(); i != e; ++i) {
502     Constant *C = 0;
503     Type *ArgTy = FTy->getParamType(i);
504     const GenericValue &AV = ArgValues[i];
505     switch (ArgTy->getTypeID()) {
506     default: llvm_unreachable("Unknown argument type for function call!");
507     case Type::IntegerTyID:
508         C = ConstantInt::get(F->getContext(), AV.IntVal);
509         break;
510     case Type::FloatTyID:
511         C = ConstantFP::get(F->getContext(), APFloat(AV.FloatVal));
512         break;
513     case Type::DoubleTyID:
514         C = ConstantFP::get(F->getContext(), APFloat(AV.DoubleVal));
515         break;
516     case Type::PPC_FP128TyID:
517     case Type::X86_FP80TyID:
518     case Type::FP128TyID:
519         C = ConstantFP::get(F->getContext(), APFloat(AV.IntVal));
520         break;
521     case Type::PointerTyID:
522       void *ArgPtr = GVTOP(AV);
523       if (sizeof(void*) == 4)
524         C = ConstantInt::get(Type::getInt32Ty(F->getContext()),
525                              (int)(intptr_t)ArgPtr);
526       else
527         C = ConstantInt::get(Type::getInt64Ty(F->getContext()),
528                              (intptr_t)ArgPtr);
529       // Cast the integer to pointer
530       C = ConstantExpr::getIntToPtr(C, ArgTy);
531       break;
532     }
533     Args.push_back(C);
534   }
535 
536   CallInst *TheCall = CallInst::Create(F, Args, "", StubBB);
537   TheCall->setCallingConv(F->getCallingConv());
538   TheCall->setTailCall();
539   if (!TheCall->getType()->isVoidTy())
540     // Return result of the call.
541     ReturnInst::Create(F->getContext(), TheCall, StubBB);
542   else
543     ReturnInst::Create(F->getContext(), StubBB);           // Just return void.
544 
545   // Finally, call our nullary stub function.
546   GenericValue Result = runFunction(Stub, std::vector<GenericValue>());
547   // Erase it, since no other function can have a reference to it.
548   Stub->eraseFromParent();
549   // And return the result.
550   return Result;
551 }
552 
RegisterJITEventListener(JITEventListener * L)553 void JIT::RegisterJITEventListener(JITEventListener *L) {
554   if (L == NULL)
555     return;
556   MutexGuard locked(lock);
557   EventListeners.push_back(L);
558 }
UnregisterJITEventListener(JITEventListener * L)559 void JIT::UnregisterJITEventListener(JITEventListener *L) {
560   if (L == NULL)
561     return;
562   MutexGuard locked(lock);
563   std::vector<JITEventListener*>::reverse_iterator I=
564       std::find(EventListeners.rbegin(), EventListeners.rend(), L);
565   if (I != EventListeners.rend()) {
566     std::swap(*I, EventListeners.back());
567     EventListeners.pop_back();
568   }
569 }
NotifyFunctionEmitted(const Function & F,void * Code,size_t Size,const JITEvent_EmittedFunctionDetails & Details)570 void JIT::NotifyFunctionEmitted(
571     const Function &F,
572     void *Code, size_t Size,
573     const JITEvent_EmittedFunctionDetails &Details) {
574   MutexGuard locked(lock);
575   for (unsigned I = 0, S = EventListeners.size(); I < S; ++I) {
576     EventListeners[I]->NotifyFunctionEmitted(F, Code, Size, Details);
577   }
578 }
579 
NotifyFreeingMachineCode(void * OldPtr)580 void JIT::NotifyFreeingMachineCode(void *OldPtr) {
581   MutexGuard locked(lock);
582   for (unsigned I = 0, S = EventListeners.size(); I < S; ++I) {
583     EventListeners[I]->NotifyFreeingMachineCode(OldPtr);
584   }
585 }
586 
587 /// runJITOnFunction - Run the FunctionPassManager full of
588 /// just-in-time compilation passes on F, hopefully filling in
589 /// GlobalAddress[F] with the address of F's machine code.
590 ///
runJITOnFunction(Function * F,MachineCodeInfo * MCI)591 void JIT::runJITOnFunction(Function *F, MachineCodeInfo *MCI) {
592   MutexGuard locked(lock);
593 
594   class MCIListener : public JITEventListener {
595     MachineCodeInfo *const MCI;
596    public:
597     MCIListener(MachineCodeInfo *mci) : MCI(mci) {}
598     virtual void NotifyFunctionEmitted(const Function &,
599                                        void *Code, size_t Size,
600                                        const EmittedFunctionDetails &) {
601       MCI->setAddress(Code);
602       MCI->setSize(Size);
603     }
604   };
605   MCIListener MCIL(MCI);
606   if (MCI)
607     RegisterJITEventListener(&MCIL);
608 
609   runJITOnFunctionUnlocked(F, locked);
610 
611   if (MCI)
612     UnregisterJITEventListener(&MCIL);
613 }
614 
runJITOnFunctionUnlocked(Function * F,const MutexGuard & locked)615 void JIT::runJITOnFunctionUnlocked(Function *F, const MutexGuard &locked) {
616   assert(!isAlreadyCodeGenerating && "Error: Recursive compilation detected!");
617 
618   jitTheFunction(F, locked);
619 
620   // If the function referred to another function that had not yet been
621   // read from bitcode, and we are jitting non-lazily, emit it now.
622   while (!jitstate->getPendingFunctions(locked).empty()) {
623     Function *PF = jitstate->getPendingFunctions(locked).back();
624     jitstate->getPendingFunctions(locked).pop_back();
625 
626     assert(!PF->hasAvailableExternallyLinkage() &&
627            "Externally-defined function should not be in pending list.");
628 
629     jitTheFunction(PF, locked);
630 
631     // Now that the function has been jitted, ask the JITEmitter to rewrite
632     // the stub with real address of the function.
633     updateFunctionStub(PF);
634   }
635 }
636 
jitTheFunction(Function * F,const MutexGuard & locked)637 void JIT::jitTheFunction(Function *F, const MutexGuard &locked) {
638   isAlreadyCodeGenerating = true;
639   jitstate->getPM(locked).run(*F);
640   isAlreadyCodeGenerating = false;
641 
642   // clear basic block addresses after this function is done
643   getBasicBlockAddressMap(locked).clear();
644 }
645 
646 /// getPointerToFunction - This method is used to get the address of the
647 /// specified function, compiling it if necessary.
648 ///
getPointerToFunction(Function * F)649 void *JIT::getPointerToFunction(Function *F) {
650 
651   if (void *Addr = getPointerToGlobalIfAvailable(F))
652     return Addr;   // Check if function already code gen'd
653 
654   MutexGuard locked(lock);
655 
656   // Now that this thread owns the lock, make sure we read in the function if it
657   // exists in this Module.
658   std::string ErrorMsg;
659   if (F->Materialize(&ErrorMsg)) {
660     report_fatal_error("Error reading function '" + F->getName()+
661                       "' from bitcode file: " + ErrorMsg);
662   }
663 
664   // ... and check if another thread has already code gen'd the function.
665   if (void *Addr = getPointerToGlobalIfAvailable(F))
666     return Addr;
667 
668   if (F->isDeclaration() || F->hasAvailableExternallyLinkage()) {
669     bool AbortOnFailure = !F->hasExternalWeakLinkage();
670     void *Addr = getPointerToNamedFunction(F->getName(), AbortOnFailure);
671     addGlobalMapping(F, Addr);
672     return Addr;
673   }
674 
675   runJITOnFunctionUnlocked(F, locked);
676 
677   void *Addr = getPointerToGlobalIfAvailable(F);
678   assert(Addr && "Code generation didn't add function to GlobalAddress table!");
679   return Addr;
680 }
681 
addPointerToBasicBlock(const BasicBlock * BB,void * Addr)682 void JIT::addPointerToBasicBlock(const BasicBlock *BB, void *Addr) {
683   MutexGuard locked(lock);
684 
685   BasicBlockAddressMapTy::iterator I =
686     getBasicBlockAddressMap(locked).find(BB);
687   if (I == getBasicBlockAddressMap(locked).end()) {
688     getBasicBlockAddressMap(locked)[BB] = Addr;
689   } else {
690     // ignore repeats: some BBs can be split into few MBBs?
691   }
692 }
693 
clearPointerToBasicBlock(const BasicBlock * BB)694 void JIT::clearPointerToBasicBlock(const BasicBlock *BB) {
695   MutexGuard locked(lock);
696   getBasicBlockAddressMap(locked).erase(BB);
697 }
698 
getPointerToBasicBlock(BasicBlock * BB)699 void *JIT::getPointerToBasicBlock(BasicBlock *BB) {
700   // make sure it's function is compiled by JIT
701   (void)getPointerToFunction(BB->getParent());
702 
703   // resolve basic block address
704   MutexGuard locked(lock);
705 
706   BasicBlockAddressMapTy::iterator I =
707     getBasicBlockAddressMap(locked).find(BB);
708   if (I != getBasicBlockAddressMap(locked).end()) {
709     return I->second;
710   } else {
711     assert(0 && "JIT does not have BB address for address-of-label, was"
712            " it eliminated by optimizer?");
713     return 0;
714   }
715 }
716 
717 /// getOrEmitGlobalVariable - Return the address of the specified global
718 /// variable, possibly emitting it to memory if needed.  This is used by the
719 /// Emitter.
getOrEmitGlobalVariable(const GlobalVariable * GV)720 void *JIT::getOrEmitGlobalVariable(const GlobalVariable *GV) {
721   MutexGuard locked(lock);
722 
723   void *Ptr = getPointerToGlobalIfAvailable(GV);
724   if (Ptr) return Ptr;
725 
726   // If the global is external, just remember the address.
727   if (GV->isDeclaration() || GV->hasAvailableExternallyLinkage()) {
728 #if HAVE___DSO_HANDLE
729     if (GV->getName() == "__dso_handle")
730       return (void*)&__dso_handle;
731 #endif
732     Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(GV->getName());
733     if (Ptr == 0) {
734       report_fatal_error("Could not resolve external global address: "
735                         +GV->getName());
736     }
737     addGlobalMapping(GV, Ptr);
738   } else {
739     // If the global hasn't been emitted to memory yet, allocate space and
740     // emit it into memory.
741     Ptr = getMemoryForGV(GV);
742     addGlobalMapping(GV, Ptr);
743     EmitGlobalVariable(GV);  // Initialize the variable.
744   }
745   return Ptr;
746 }
747 
748 /// recompileAndRelinkFunction - This method is used to force a function
749 /// which has already been compiled, to be compiled again, possibly
750 /// after it has been modified. Then the entry to the old copy is overwritten
751 /// with a branch to the new copy. If there was no old copy, this acts
752 /// just like JIT::getPointerToFunction().
753 ///
recompileAndRelinkFunction(Function * F)754 void *JIT::recompileAndRelinkFunction(Function *F) {
755   void *OldAddr = getPointerToGlobalIfAvailable(F);
756 
757   // If it's not already compiled there is no reason to patch it up.
758   if (OldAddr == 0) { return getPointerToFunction(F); }
759 
760   // Delete the old function mapping.
761   addGlobalMapping(F, 0);
762 
763   // Recodegen the function
764   runJITOnFunction(F);
765 
766   // Update state, forward the old function to the new function.
767   void *Addr = getPointerToGlobalIfAvailable(F);
768   assert(Addr && "Code generation didn't add function to GlobalAddress table!");
769   TJI.replaceMachineCodeForFunction(OldAddr, Addr);
770   return Addr;
771 }
772 
773 /// getMemoryForGV - This method abstracts memory allocation of global
774 /// variable so that the JIT can allocate thread local variables depending
775 /// on the target.
776 ///
getMemoryForGV(const GlobalVariable * GV)777 char* JIT::getMemoryForGV(const GlobalVariable* GV) {
778   char *Ptr;
779 
780   // GlobalVariable's which are not "constant" will cause trouble in a server
781   // situation. It's returned in the same block of memory as code which may
782   // not be writable.
783   if (isGVCompilationDisabled() && !GV->isConstant()) {
784     report_fatal_error("Compilation of non-internal GlobalValue is disabled!");
785   }
786 
787   // Some applications require globals and code to live together, so they may
788   // be allocated into the same buffer, but in general globals are allocated
789   // through the memory manager which puts them near the code but not in the
790   // same buffer.
791   Type *GlobalType = GV->getType()->getElementType();
792   size_t S = getTargetData()->getTypeAllocSize(GlobalType);
793   size_t A = getTargetData()->getPreferredAlignment(GV);
794   if (GV->isThreadLocal()) {
795     MutexGuard locked(lock);
796     Ptr = TJI.allocateThreadLocalMemory(S);
797   } else if (TJI.allocateSeparateGVMemory()) {
798     if (A <= 8) {
799       Ptr = (char*)malloc(S);
800     } else {
801       // Allocate S+A bytes of memory, then use an aligned pointer within that
802       // space.
803       Ptr = (char*)malloc(S+A);
804       unsigned MisAligned = ((intptr_t)Ptr & (A-1));
805       Ptr = Ptr + (MisAligned ? (A-MisAligned) : 0);
806     }
807   } else if (AllocateGVsWithCode) {
808     Ptr = (char*)JCE->allocateSpace(S, A);
809   } else {
810     Ptr = (char*)JCE->allocateGlobal(S, A);
811   }
812   return Ptr;
813 }
814 
addPendingFunction(Function * F)815 void JIT::addPendingFunction(Function *F) {
816   MutexGuard locked(lock);
817   jitstate->getPendingFunctions(locked).push_back(F);
818 }
819 
820 
~JITEventListener()821 JITEventListener::~JITEventListener() {}
822