ParallelJIT.cpp revision fc001bbfc360ab828e5a4b0cbe4bb7db87361b85
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 <pthread.h> 21#include "llvm/Module.h" 22#include "llvm/Constants.h" 23#include "llvm/DerivedTypes.h" 24#include "llvm/Instructions.h" 25#include "llvm/ModuleProvider.h" 26#include "llvm/ExecutionEngine/JIT.h" 27#include "llvm/ExecutionEngine/Interpreter.h" 28#include "llvm/ExecutionEngine/GenericValue.h" 29#include <iostream> 30using namespace llvm; 31 32static Function* createAdd1(Module *M) { 33 // Create the add1 function entry and insert this entry into module M. The 34 // function will have a return type of "int" and take an argument of "int". 35 // The '0' terminates the list of argument types. 36 Function *Add1F = 37 cast<Function>(M->getOrInsertFunction("add1", Type::Int32Ty, Type::Int32Ty, 38 (Type *)0)); 39 40 // Add a basic block to the function. As before, it automatically inserts 41 // because of the last argument. 42 BasicBlock *BB = new BasicBlock("EntryBlock", Add1F); 43 44 // Get pointers to the constant `1'. 45 Value *One = ConstantInt::get(Type::Int32Ty, 1); 46 47 // Get pointers to the integer argument of the add1 function... 48 assert(Add1F->arg_begin() != Add1F->arg_end()); // Make sure there's an arg 49 Argument *ArgX = Add1F->arg_begin(); // Get the arg 50 ArgX->setName("AnArg"); // Give it a nice symbolic name for fun. 51 52 // Create the add instruction, inserting it into the end of BB. 53 Instruction *Add = BinaryOperator::createAdd(One, ArgX, "addresult", BB); 54 55 // Create the return instruction and add it to the basic block 56 new ReturnInst(Add, BB); 57 58 // Now, function add1 is ready. 59 return Add1F; 60} 61 62static Function *CreateFibFunction(Module *M) { 63 // Create the fib function and insert it into module M. This function is said 64 // to return an int and take an int parameter. 65 Function *FibF = 66 cast<Function>(M->getOrInsertFunction("fib", Type::Int32Ty, Type::Int32Ty, 67 (Type *)0)); 68 69 // Add a basic block to the function. 70 BasicBlock *BB = new BasicBlock("EntryBlock", FibF); 71 72 // Get pointers to the constants. 73 Value *One = ConstantInt::get(Type::Int32Ty, 1); 74 Value *Two = ConstantInt::get(Type::Int32Ty, 2); 75 76 // Get pointer to the integer argument of the add1 function... 77 Argument *ArgX = FibF->arg_begin(); // Get the arg. 78 ArgX->setName("AnArg"); // Give it a nice symbolic name for fun. 79 80 // Create the true_block. 81 BasicBlock *RetBB = new BasicBlock("return", FibF); 82 // Create an exit block. 83 BasicBlock* RecurseBB = new BasicBlock("recurse", FibF); 84 85 // Create the "if (arg < 2) goto exitbb" 86 Value *CondInst = new ICmpInst(ICmpInst::ICMP_SLE, ArgX, Two, "cond", BB); 87 new BranchInst(RetBB, RecurseBB, CondInst, BB); 88 89 // Create: ret int 1 90 new ReturnInst(One, RetBB); 91 92 // create fib(x-1) 93 Value *Sub = BinaryOperator::createSub(ArgX, One, "arg", RecurseBB); 94 Value *CallFibX1 = new CallInst(FibF, Sub, "fibx1", RecurseBB); 95 96 // create fib(x-2) 97 Sub = BinaryOperator::createSub(ArgX, Two, "arg", RecurseBB); 98 Value *CallFibX2 = new CallInst(FibF, Sub, "fibx2", RecurseBB); 99 100 // fib(x-1)+fib(x-2) 101 Value *Sum = 102 BinaryOperator::createAdd(CallFibX1, CallFibX2, "addresult", RecurseBB); 103 104 // Create the return instruction and add it to the basic block 105 new ReturnInst(Sum, RecurseBB); 106 107 return FibF; 108} 109 110struct threadParams { 111 ExecutionEngine* EE; 112 Function* F; 113 int value; 114}; 115 116// We block the subthreads just before they begin to execute: 117// we want all of them to call into the JIT at the same time, 118// to verify that the locking is working correctly. 119class WaitForThreads 120{ 121public: 122 WaitForThreads() 123 { 124 n = 0; 125 waitFor = 0; 126 127 int result = pthread_cond_init( &condition, NULL ); 128 assert( result == 0 ); 129 130 result = pthread_mutex_init( &mutex, NULL ); 131 assert( result == 0 ); 132 } 133 134 ~WaitForThreads() 135 { 136 int result = pthread_cond_destroy( &condition ); 137 assert( result == 0 ); 138 139 result = pthread_mutex_destroy( &mutex ); 140 assert( result == 0 ); 141 } 142 143 // All threads will stop here until another thread calls releaseThreads 144 void block() 145 { 146 int result = pthread_mutex_lock( &mutex ); 147 assert( result == 0 ); 148 n ++; 149 //~ std::cout << "block() n " << n << " waitFor " << waitFor << std::endl; 150 151 assert( waitFor == 0 || n <= waitFor ); 152 if ( waitFor > 0 && n == waitFor ) 153 { 154 // There are enough threads blocked that we can release all of them 155 std::cout << "Unblocking threads from block()" << std::endl; 156 unblockThreads(); 157 } 158 else 159 { 160 // We just need to wait until someone unblocks us 161 result = pthread_cond_wait( &condition, &mutex ); 162 assert( result == 0 ); 163 } 164 165 // unlock the mutex before returning 166 result = pthread_mutex_unlock( &mutex ); 167 assert( result == 0 ); 168 } 169 170 // If there are num or more threads blocked, it will signal them all 171 // Otherwise, this thread blocks until there are enough OTHER threads 172 // blocked 173 void releaseThreads( size_t num ) 174 { 175 int result = pthread_mutex_lock( &mutex ); 176 assert( result == 0 ); 177 178 if ( n >= num ) { 179 std::cout << "Unblocking threads from releaseThreads()" << std::endl; 180 unblockThreads(); 181 } 182 else 183 { 184 waitFor = num; 185 pthread_cond_wait( &condition, &mutex ); 186 } 187 188 // unlock the mutex before returning 189 result = pthread_mutex_unlock( &mutex ); 190 assert( result == 0 ); 191 } 192 193private: 194 void unblockThreads() 195 { 196 // Reset the counters to zero: this way, if any new threads 197 // enter while threads are exiting, they will block instead 198 // of triggering a new release of threads 199 n = 0; 200 201 // Reset waitFor to zero: this way, if waitFor threads enter 202 // while threads are exiting, they will block instead of 203 // triggering a new release of threads 204 waitFor = 0; 205 206 int result = pthread_cond_broadcast( &condition ); 207 assert( result == 0 ); 208 } 209 210 size_t n; 211 size_t waitFor; 212 pthread_cond_t condition; 213 pthread_mutex_t mutex; 214}; 215 216static WaitForThreads synchronize; 217 218void* callFunc( void* param ) 219{ 220 struct threadParams* p = (struct threadParams*) param; 221 222 // Call the `foo' function with no arguments: 223 std::vector<GenericValue> Args(1); 224 Args[0].IntVal = APInt(32, p->value); 225 226 synchronize.block(); // wait until other threads are at this point 227 GenericValue gv = p->EE->runFunction(p->F, Args); 228 229 return (void*)(intptr_t)gv.IntVal.getZExtValue(); 230} 231 232int main() 233{ 234 // Create some module to put our function into it. 235 Module *M = new Module("test"); 236 237 Function* add1F = createAdd1( M ); 238 Function* fibF = CreateFibFunction( M ); 239 240 // Now we create the JIT. 241 ExistingModuleProvider* MP = new ExistingModuleProvider(M); 242 ExecutionEngine* EE = ExecutionEngine::create(MP, false); 243 244 //~ std::cout << "We just constructed this LLVM module:\n\n" << *M; 245 //~ std::cout << "\n\nRunning foo: " << std::flush; 246 247 // Create one thread for add1 and two threads for fib 248 struct threadParams add1 = { EE, add1F, 1000 }; 249 struct threadParams fib1 = { EE, fibF, 39 }; 250 struct threadParams fib2 = { EE, fibF, 42 }; 251 252 pthread_t add1Thread; 253 int result = pthread_create( &add1Thread, NULL, callFunc, &add1 ); 254 if ( result != 0 ) { 255 std::cerr << "Could not create thread" << std::endl; 256 return 1; 257 } 258 259 pthread_t fibThread1; 260 result = pthread_create( &fibThread1, NULL, callFunc, &fib1 ); 261 if ( result != 0 ) { 262 std::cerr << "Could not create thread" << std::endl; 263 return 1; 264 } 265 266 pthread_t fibThread2; 267 result = pthread_create( &fibThread2, NULL, callFunc, &fib2 ); 268 if ( result != 0 ) { 269 std::cerr << "Could not create thread" << std::endl; 270 return 1; 271 } 272 273 synchronize.releaseThreads(3); // wait until other threads are at this point 274 275 void* returnValue; 276 result = pthread_join( add1Thread, &returnValue ); 277 if ( result != 0 ) { 278 std::cerr << "Could not join thread" << std::endl; 279 return 1; 280 } 281 std::cout << "Add1 returned " << intptr_t(returnValue) << std::endl; 282 283 result = pthread_join( fibThread1, &returnValue ); 284 if ( result != 0 ) { 285 std::cerr << "Could not join thread" << std::endl; 286 return 1; 287 } 288 std::cout << "Fib1 returned " << intptr_t(returnValue) << std::endl; 289 290 result = pthread_join( fibThread2, &returnValue ); 291 if ( result != 0 ) { 292 std::cerr << "Could not join thread" << std::endl; 293 return 1; 294 } 295 std::cout << "Fib2 returned " << intptr_t(returnValue) << std::endl; 296 297 return 0; 298} 299