1 //===-- examples/ParallelJIT/ParallelJIT.cpp - Exercise threaded-safe JIT -===// 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 // Parallel JIT 11 // 12 // This test program creates two LLVM functions then calls them from three 13 // separate threads. It requires the pthreads library. 14 // The three threads are created and then block waiting on a condition variable. 15 // Once all threads are blocked on the conditional variable, the main thread 16 // wakes them up. This complicated work is performed so that all three threads 17 // call into the JIT at the same time (or the best possible approximation of the 18 // same time). This test had assertion errors until I got the locking right. 19 20 #include "llvm/ExecutionEngine/GenericValue.h" 21 #include "llvm/ExecutionEngine/Interpreter.h" 22 #include "llvm/ExecutionEngine/JIT.h" 23 #include "llvm/IR/Constants.h" 24 #include "llvm/IR/DerivedTypes.h" 25 #include "llvm/IR/Instructions.h" 26 #include "llvm/IR/LLVMContext.h" 27 #include "llvm/IR/Module.h" 28 #include "llvm/Support/TargetSelect.h" 29 #include <iostream> 30 #include <pthread.h> 31 using namespace llvm; 32 33 static Function* createAdd1(Module *M) { 34 // Create the add1 function entry and insert this entry into module M. The 35 // function will have a return type of "int" and take an argument of "int". 36 // The '0' terminates the list of argument types. 37 Function *Add1F = 38 cast<Function>(M->getOrInsertFunction("add1", 39 Type::getInt32Ty(M->getContext()), 40 Type::getInt32Ty(M->getContext()), 41 (Type *)0)); 42 43 // Add a basic block to the function. As before, it automatically inserts 44 // because of the last argument. 45 BasicBlock *BB = BasicBlock::Create(M->getContext(), "EntryBlock", Add1F); 46 47 // Get pointers to the constant `1'. 48 Value *One = ConstantInt::get(Type::getInt32Ty(M->getContext()), 1); 49 50 // Get pointers to the integer argument of the add1 function... 51 assert(Add1F->arg_begin() != Add1F->arg_end()); // Make sure there's an arg 52 Argument *ArgX = Add1F->arg_begin(); // Get the arg 53 ArgX->setName("AnArg"); // Give it a nice symbolic name for fun. 54 55 // Create the add instruction, inserting it into the end of BB. 56 Instruction *Add = BinaryOperator::CreateAdd(One, ArgX, "addresult", BB); 57 58 // Create the return instruction and add it to the basic block 59 ReturnInst::Create(M->getContext(), Add, BB); 60 61 // Now, function add1 is ready. 62 return Add1F; 63 } 64 65 static Function *CreateFibFunction(Module *M) { 66 // Create the fib function and insert it into module M. This function is said 67 // to return an int and take an int parameter. 68 Function *FibF = 69 cast<Function>(M->getOrInsertFunction("fib", 70 Type::getInt32Ty(M->getContext()), 71 Type::getInt32Ty(M->getContext()), 72 (Type *)0)); 73 74 // Add a basic block to the function. 75 BasicBlock *BB = BasicBlock::Create(M->getContext(), "EntryBlock", FibF); 76 77 // Get pointers to the constants. 78 Value *One = ConstantInt::get(Type::getInt32Ty(M->getContext()), 1); 79 Value *Two = ConstantInt::get(Type::getInt32Ty(M->getContext()), 2); 80 81 // Get pointer to the integer argument of the add1 function... 82 Argument *ArgX = FibF->arg_begin(); // Get the arg. 83 ArgX->setName("AnArg"); // Give it a nice symbolic name for fun. 84 85 // Create the true_block. 86 BasicBlock *RetBB = BasicBlock::Create(M->getContext(), "return", FibF); 87 // Create an exit block. 88 BasicBlock* RecurseBB = BasicBlock::Create(M->getContext(), "recurse", FibF); 89 90 // Create the "if (arg < 2) goto exitbb" 91 Value *CondInst = new ICmpInst(*BB, ICmpInst::ICMP_SLE, ArgX, Two, "cond"); 92 BranchInst::Create(RetBB, RecurseBB, CondInst, BB); 93 94 // Create: ret int 1 95 ReturnInst::Create(M->getContext(), One, RetBB); 96 97 // create fib(x-1) 98 Value *Sub = BinaryOperator::CreateSub(ArgX, One, "arg", RecurseBB); 99 Value *CallFibX1 = CallInst::Create(FibF, Sub, "fibx1", RecurseBB); 100 101 // create fib(x-2) 102 Sub = BinaryOperator::CreateSub(ArgX, Two, "arg", RecurseBB); 103 Value *CallFibX2 = CallInst::Create(FibF, Sub, "fibx2", RecurseBB); 104 105 // fib(x-1)+fib(x-2) 106 Value *Sum = 107 BinaryOperator::CreateAdd(CallFibX1, CallFibX2, "addresult", RecurseBB); 108 109 // Create the return instruction and add it to the basic block 110 ReturnInst::Create(M->getContext(), Sum, RecurseBB); 111 112 return FibF; 113 } 114 115 struct threadParams { 116 ExecutionEngine* EE; 117 Function* F; 118 int value; 119 }; 120 121 // We block the subthreads just before they begin to execute: 122 // we want all of them to call into the JIT at the same time, 123 // to verify that the locking is working correctly. 124 class WaitForThreads 125 { 126 public: 127 WaitForThreads() 128 { 129 n = 0; 130 waitFor = 0; 131 132 int result = pthread_cond_init( &condition, NULL ); 133 assert( result == 0 ); 134 135 result = pthread_mutex_init( &mutex, NULL ); 136 assert( result == 0 ); 137 } 138 139 ~WaitForThreads() 140 { 141 int result = pthread_cond_destroy( &condition ); 142 (void)result; 143 assert( result == 0 ); 144 145 result = pthread_mutex_destroy( &mutex ); 146 assert( result == 0 ); 147 } 148 149 // All threads will stop here until another thread calls releaseThreads 150 void block() 151 { 152 int result = pthread_mutex_lock( &mutex ); 153 (void)result; 154 assert( result == 0 ); 155 n ++; 156 //~ std::cout << "block() n " << n << " waitFor " << waitFor << std::endl; 157 158 assert( waitFor == 0 || n <= waitFor ); 159 if ( waitFor > 0 && n == waitFor ) 160 { 161 // There are enough threads blocked that we can release all of them 162 std::cout << "Unblocking threads from block()" << std::endl; 163 unblockThreads(); 164 } 165 else 166 { 167 // We just need to wait until someone unblocks us 168 result = pthread_cond_wait( &condition, &mutex ); 169 assert( result == 0 ); 170 } 171 172 // unlock the mutex before returning 173 result = pthread_mutex_unlock( &mutex ); 174 assert( result == 0 ); 175 } 176 177 // If there are num or more threads blocked, it will signal them all 178 // Otherwise, this thread blocks until there are enough OTHER threads 179 // blocked 180 void releaseThreads( size_t num ) 181 { 182 int result = pthread_mutex_lock( &mutex ); 183 (void)result; 184 assert( result == 0 ); 185 186 if ( n >= num ) { 187 std::cout << "Unblocking threads from releaseThreads()" << std::endl; 188 unblockThreads(); 189 } 190 else 191 { 192 waitFor = num; 193 pthread_cond_wait( &condition, &mutex ); 194 } 195 196 // unlock the mutex before returning 197 result = pthread_mutex_unlock( &mutex ); 198 assert( result == 0 ); 199 } 200 201 private: 202 void unblockThreads() 203 { 204 // Reset the counters to zero: this way, if any new threads 205 // enter while threads are exiting, they will block instead 206 // of triggering a new release of threads 207 n = 0; 208 209 // Reset waitFor to zero: this way, if waitFor threads enter 210 // while threads are exiting, they will block instead of 211 // triggering a new release of threads 212 waitFor = 0; 213 214 int result = pthread_cond_broadcast( &condition ); 215 (void)result; 216 assert(result == 0); 217 } 218 219 size_t n; 220 size_t waitFor; 221 pthread_cond_t condition; 222 pthread_mutex_t mutex; 223 }; 224 225 static WaitForThreads synchronize; 226 227 void* callFunc( void* param ) 228 { 229 struct threadParams* p = (struct threadParams*) param; 230 231 // Call the `foo' function with no arguments: 232 std::vector<GenericValue> Args(1); 233 Args[0].IntVal = APInt(32, p->value); 234 235 synchronize.block(); // wait until other threads are at this point 236 GenericValue gv = p->EE->runFunction(p->F, Args); 237 238 return (void*)(intptr_t)gv.IntVal.getZExtValue(); 239 } 240 241 int main() { 242 InitializeNativeTarget(); 243 LLVMContext Context; 244 245 // Create some module to put our function into it. 246 Module *M = new Module("test", Context); 247 248 Function* add1F = createAdd1( M ); 249 Function* fibF = CreateFibFunction( M ); 250 251 // Now we create the JIT. 252 ExecutionEngine* EE = EngineBuilder(M).create(); 253 254 //~ std::cout << "We just constructed this LLVM module:\n\n" << *M; 255 //~ std::cout << "\n\nRunning foo: " << std::flush; 256 257 // Create one thread for add1 and two threads for fib 258 struct threadParams add1 = { EE, add1F, 1000 }; 259 struct threadParams fib1 = { EE, fibF, 39 }; 260 struct threadParams fib2 = { EE, fibF, 42 }; 261 262 pthread_t add1Thread; 263 int result = pthread_create( &add1Thread, NULL, callFunc, &add1 ); 264 if ( result != 0 ) { 265 std::cerr << "Could not create thread" << std::endl; 266 return 1; 267 } 268 269 pthread_t fibThread1; 270 result = pthread_create( &fibThread1, NULL, callFunc, &fib1 ); 271 if ( result != 0 ) { 272 std::cerr << "Could not create thread" << std::endl; 273 return 1; 274 } 275 276 pthread_t fibThread2; 277 result = pthread_create( &fibThread2, NULL, callFunc, &fib2 ); 278 if ( result != 0 ) { 279 std::cerr << "Could not create thread" << std::endl; 280 return 1; 281 } 282 283 synchronize.releaseThreads(3); // wait until other threads are at this point 284 285 void* returnValue; 286 result = pthread_join( add1Thread, &returnValue ); 287 if ( result != 0 ) { 288 std::cerr << "Could not join thread" << std::endl; 289 return 1; 290 } 291 std::cout << "Add1 returned " << intptr_t(returnValue) << std::endl; 292 293 result = pthread_join( fibThread1, &returnValue ); 294 if ( result != 0 ) { 295 std::cerr << "Could not join thread" << std::endl; 296 return 1; 297 } 298 std::cout << "Fib1 returned " << intptr_t(returnValue) << std::endl; 299 300 result = pthread_join( fibThread2, &returnValue ); 301 if ( result != 0 ) { 302 std::cerr << "Could not join thread" << std::endl; 303 return 1; 304 } 305 std::cout << "Fib2 returned " << intptr_t(returnValue) << std::endl; 306 307 return 0; 308 } 309