ParallelJIT.cpp revision 6fb0d735f0ffdf4cd1b0a1fa04bd436586097448
1//===-- examples/ParallelJIT/ParallelJIT.cpp - Exercise threaded-safe JIT -===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file was developed by Evan Jones and is distributed under the 6// University of Illinois Open Source 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/Type.h" 24#include "llvm/Instructions.h" 25#include "llvm/ModuleProvider.h" 26#include "llvm/ExecutionEngine/ExecutionEngine.h" 27#include "llvm/ExecutionEngine/GenericValue.h" 28#include <iostream> 29using namespace llvm; 30 31static Function* createAdd1( Module* M ) 32{ 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 = M->getOrInsertFunction("add1", Type::IntTy, Type::IntTy, 0); 37 38 // Add a basic block to the function. As before, it automatically inserts 39 // because of the last argument. 40 BasicBlock *BB = new BasicBlock("EntryBlock", Add1F); 41 42 // Get pointers to the constant `1'. 43 Value *One = ConstantSInt::get(Type::IntTy, 1); 44 45 // Get pointers to the integer argument of the add1 function... 46 assert(Add1F->arg_begin() != Add1F->arg_end()); // Make sure there's an arg 47 Argument *ArgX = Add1F->arg_begin(); // Get the arg 48 ArgX->setName("AnArg"); // Give it a nice symbolic name for fun. 49 50 // Create the add instruction, inserting it into the end of BB. 51 Instruction *Add = BinaryOperator::createAdd(One, ArgX, "addresult", BB); 52 53 // Create the return instruction and add it to the basic block 54 new ReturnInst(Add, BB); 55 56 // Now, function add1 is ready. 57 return Add1F; 58} 59 60static Function *CreateFibFunction(Module *M) 61{ 62 // Create the fib function and insert it into module M. This function is said 63 // to return an int and take an int parameter. 64 Function *FibF = M->getOrInsertFunction("fib", Type::IntTy, Type::IntTy, 0); 65 66 // Add a basic block to the function. 67 BasicBlock *BB = new BasicBlock("EntryBlock", FibF); 68 69 // Get pointers to the constants. 70 Value *One = ConstantSInt::get(Type::IntTy, 1); 71 Value *Two = ConstantSInt::get(Type::IntTy, 2); 72 73 // Get pointer to the integer argument of the add1 function... 74 Argument *ArgX = FibF->arg_begin(); // Get the arg. 75 ArgX->setName("AnArg"); // Give it a nice symbolic name for fun. 76 77 // Create the true_block. 78 BasicBlock *RetBB = new BasicBlock("return", FibF); 79 // Create an exit block. 80 BasicBlock* RecurseBB = new BasicBlock("recurse", FibF); 81 82 // Create the "if (arg < 2) goto exitbb" 83 Value *CondInst = BinaryOperator::createSetLE(ArgX, Two, "cond", BB); 84 new BranchInst(RetBB, RecurseBB, CondInst, BB); 85 86 // Create: ret int 1 87 new ReturnInst(One, RetBB); 88 89 // create fib(x-1) 90 Value *Sub = BinaryOperator::createSub(ArgX, One, "arg", RecurseBB); 91 Value *CallFibX1 = new CallInst(FibF, Sub, "fibx1", RecurseBB); 92 93 // create fib(x-2) 94 Sub = BinaryOperator::createSub(ArgX, Two, "arg", RecurseBB); 95 Value *CallFibX2 = new CallInst(FibF, Sub, "fibx2", RecurseBB); 96 97 // fib(x-1)+fib(x-2) 98 Value *Sum = 99 BinaryOperator::createAdd(CallFibX1, CallFibX2, "addresult", RecurseBB); 100 101 // Create the return instruction and add it to the basic block 102 new ReturnInst(Sum, RecurseBB); 103 104 return FibF; 105} 106 107struct threadParams { 108 ExecutionEngine* EE; 109 Function* F; 110 int value; 111}; 112 113// We block the subthreads just before they begin to execute: 114// we want all of them to call into the JIT at the same time, 115// to verify that the locking is working correctly. 116class WaitForThreads 117{ 118public: 119 WaitForThreads() 120 { 121 n = 0; 122 waitFor = 0; 123 124 int result = pthread_cond_init( &condition, NULL ); 125 assert( result == 0 ); 126 127 result = pthread_mutex_init( &mutex, NULL ); 128 assert( result == 0 ); 129 } 130 131 ~WaitForThreads() 132 { 133 int result = pthread_cond_destroy( &condition ); 134 assert( result == 0 ); 135 136 result = pthread_mutex_destroy( &mutex ); 137 assert( result == 0 ); 138 } 139 140 // All threads will stop here until another thread calls releaseThreads 141 void block() 142 { 143 int result = pthread_mutex_lock( &mutex ); 144 assert( result == 0 ); 145 n ++; 146 //~ std::cout << "block() n " << n << " waitFor " << waitFor << std::endl; 147 148 assert( waitFor == 0 || n <= waitFor ); 149 if ( waitFor > 0 && n == waitFor ) 150 { 151 // There are enough threads blocked that we can release all of them 152 std::cout << "Unblocking threads from block()" << std::endl; 153 unblockThreads(); 154 } 155 else 156 { 157 // We just need to wait until someone unblocks us 158 result = pthread_cond_wait( &condition, &mutex ); 159 assert( result == 0 ); 160 } 161 162 // unlock the mutex before returning 163 result = pthread_mutex_unlock( &mutex ); 164 assert( result == 0 ); 165 } 166 167 // If there are num or more threads blocked, it will signal them all 168 // Otherwise, this thread blocks until there are enough OTHER threads 169 // blocked 170 void releaseThreads( size_t num ) 171 { 172 int result = pthread_mutex_lock( &mutex ); 173 assert( result == 0 ); 174 175 if ( n >= num ) { 176 std::cout << "Unblocking threads from releaseThreads()" << std::endl; 177 unblockThreads(); 178 } 179 else 180 { 181 waitFor = num; 182 pthread_cond_wait( &condition, &mutex ); 183 } 184 185 // unlock the mutex before returning 186 result = pthread_mutex_unlock( &mutex ); 187 assert( result == 0 ); 188 } 189 190private: 191 void unblockThreads() 192 { 193 // Reset the counters to zero: this way, if any new threads 194 // enter while threads are exiting, they will block instead 195 // of triggering a new release of threads 196 n = 0; 197 198 // Reset waitFor to zero: this way, if waitFor threads enter 199 // while threads are exiting, they will block instead of 200 // triggering a new release of threads 201 waitFor = 0; 202 203 int result = pthread_cond_broadcast( &condition ); 204 assert( result == 0 ); 205 } 206 207 size_t n; 208 size_t waitFor; 209 pthread_cond_t condition; 210 pthread_mutex_t mutex; 211}; 212 213static WaitForThreads synchronize; 214 215void* callFunc( void* param ) 216{ 217 struct threadParams* p = (struct threadParams*) param; 218 219 // Call the `foo' function with no arguments: 220 std::vector<GenericValue> Args(1); 221 Args[0].IntVal = p->value; 222 223 synchronize.block(); // wait until other threads are at this point 224 GenericValue gv = p->EE->runFunction(p->F, Args); 225 226 return (void*) intptr_t(gv.IntVal); 227} 228 229int main() 230{ 231 // Create some module to put our function into it. 232 Module *M = new Module("test"); 233 234 Function* add1F = createAdd1( M ); 235 Function* fibF = CreateFibFunction( M ); 236 237 // Now we create the JIT. 238 ExistingModuleProvider* MP = new ExistingModuleProvider(M); 239 ExecutionEngine* EE = ExecutionEngine::create(MP, false); 240 241 //~ std::cout << "We just constructed this LLVM module:\n\n" << *M; 242 //~ std::cout << "\n\nRunning foo: " << std::flush; 243 244 // Create one thread for add1 and two threads for fib 245 struct threadParams add1 = { EE, add1F, 1000 }; 246 struct threadParams fib1 = { EE, fibF, 39 }; 247 struct threadParams fib2 = { EE, fibF, 42 }; 248 249 pthread_t add1Thread; 250 int result = pthread_create( &add1Thread, NULL, callFunc, &add1 ); 251 if ( result != 0 ) { 252 std::cerr << "Could not create thread" << std::endl; 253 return 1; 254 } 255 256 pthread_t fibThread1; 257 result = pthread_create( &fibThread1, NULL, callFunc, &fib1 ); 258 if ( result != 0 ) { 259 std::cerr << "Could not create thread" << std::endl; 260 return 1; 261 } 262 263 pthread_t fibThread2; 264 result = pthread_create( &fibThread2, NULL, callFunc, &fib2 ); 265 if ( result != 0 ) { 266 std::cerr << "Could not create thread" << std::endl; 267 return 1; 268 } 269 270 synchronize.releaseThreads(3); // wait until other threads are at this point 271 272 void* returnValue; 273 result = pthread_join( add1Thread, &returnValue ); 274 if ( result != 0 ) { 275 std::cerr << "Could not join thread" << std::endl; 276 return 1; 277 } 278 std::cout << "Add1 returned " << intptr_t(returnValue) << std::endl; 279 280 result = pthread_join( fibThread1, &returnValue ); 281 if ( result != 0 ) { 282 std::cerr << "Could not join thread" << std::endl; 283 return 1; 284 } 285 std::cout << "Fib1 returned " << intptr_t(returnValue) << std::endl; 286 287 result = pthread_join( fibThread2, &returnValue ); 288 if ( result != 0 ) { 289 std::cerr << "Could not join thread" << std::endl; 290 return 1; 291 } 292 std::cout << "Fib2 returned " << intptr_t(returnValue) << std::endl; 293 294 return 0; 295} 296