ParallelJIT.cpp revision 1d0be15f89cb5056e20e2d24faa8d6afb1573bca
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/LLVMContext.h" 22#include "llvm/Module.h" 23#include "llvm/Constants.h" 24#include "llvm/DerivedTypes.h" 25#include "llvm/Instructions.h" 26#include "llvm/ModuleProvider.h" 27#include "llvm/ExecutionEngine/JIT.h" 28#include "llvm/ExecutionEngine/Interpreter.h" 29#include "llvm/ExecutionEngine/GenericValue.h" 30#include "llvm/Target/TargetSelect.h" 31#include <iostream> 32using namespace llvm; 33 34static Function* createAdd1(Module *M) { 35 // Create the add1 function entry and insert this entry into module M. The 36 // function will have a return type of "int" and take an argument of "int". 37 // The '0' terminates the list of argument types. 38 Function *Add1F = 39 cast<Function>(M->getOrInsertFunction("add1", 40 Type::getInt32Ty(M->getContext()), 41 Type::getInt32Ty(M->getContext()), 42 (Type *)0)); 43 44 // Add a basic block to the function. As before, it automatically inserts 45 // because of the last argument. 46 BasicBlock *BB = BasicBlock::Create(M->getContext(), "EntryBlock", Add1F); 47 48 // Get pointers to the constant `1'. 49 Value *One = ConstantInt::get(Type::getInt32Ty(M->getContext()), 1); 50 51 // Get pointers to the integer argument of the add1 function... 52 assert(Add1F->arg_begin() != Add1F->arg_end()); // Make sure there's an arg 53 Argument *ArgX = Add1F->arg_begin(); // Get the arg 54 ArgX->setName("AnArg"); // Give it a nice symbolic name for fun. 55 56 // Create the add instruction, inserting it into the end of BB. 57 Instruction *Add = BinaryOperator::CreateAdd(One, ArgX, "addresult", BB); 58 59 // Create the return instruction and add it to the basic block 60 ReturnInst::Create(M->getContext(), Add, BB); 61 62 // Now, function add1 is ready. 63 return Add1F; 64} 65 66static Function *CreateFibFunction(Module *M) { 67 // Create the fib function and insert it into module M. This function is said 68 // to return an int and take an int parameter. 69 Function *FibF = 70 cast<Function>(M->getOrInsertFunction("fib", 71 Type::getInt32Ty(M->getContext()), 72 Type::getInt32Ty(M->getContext()), 73 (Type *)0)); 74 75 // Add a basic block to the function. 76 BasicBlock *BB = BasicBlock::Create(M->getContext(), "EntryBlock", FibF); 77 78 // Get pointers to the constants. 79 Value *One = ConstantInt::get(Type::getInt32Ty(M->getContext()), 1); 80 Value *Two = ConstantInt::get(Type::getInt32Ty(M->getContext()), 2); 81 82 // Get pointer to the integer argument of the add1 function... 83 Argument *ArgX = FibF->arg_begin(); // Get the arg. 84 ArgX->setName("AnArg"); // Give it a nice symbolic name for fun. 85 86 // Create the true_block. 87 BasicBlock *RetBB = BasicBlock::Create(M->getContext(), "return", FibF); 88 // Create an exit block. 89 BasicBlock* RecurseBB = BasicBlock::Create(M->getContext(), "recurse", FibF); 90 91 // Create the "if (arg < 2) goto exitbb" 92 Value *CondInst = new ICmpInst(*BB, ICmpInst::ICMP_SLE, ArgX, Two, "cond"); 93 BranchInst::Create(RetBB, RecurseBB, CondInst, BB); 94 95 // Create: ret int 1 96 ReturnInst::Create(M->getContext(), One, RetBB); 97 98 // create fib(x-1) 99 Value *Sub = BinaryOperator::CreateSub(ArgX, One, "arg", RecurseBB); 100 Value *CallFibX1 = CallInst::Create(FibF, Sub, "fibx1", RecurseBB); 101 102 // create fib(x-2) 103 Sub = BinaryOperator::CreateSub(ArgX, Two, "arg", RecurseBB); 104 Value *CallFibX2 = CallInst::Create(FibF, Sub, "fibx2", RecurseBB); 105 106 // fib(x-1)+fib(x-2) 107 Value *Sum = 108 BinaryOperator::CreateAdd(CallFibX1, CallFibX2, "addresult", RecurseBB); 109 110 // Create the return instruction and add it to the basic block 111 ReturnInst::Create(M->getContext(), Sum, RecurseBB); 112 113 return FibF; 114} 115 116struct threadParams { 117 ExecutionEngine* EE; 118 Function* F; 119 int value; 120}; 121 122// We block the subthreads just before they begin to execute: 123// we want all of them to call into the JIT at the same time, 124// to verify that the locking is working correctly. 125class WaitForThreads 126{ 127public: 128 WaitForThreads() 129 { 130 n = 0; 131 waitFor = 0; 132 133 int result = pthread_cond_init( &condition, NULL ); 134 assert( result == 0 ); 135 136 result = pthread_mutex_init( &mutex, NULL ); 137 assert( result == 0 ); 138 } 139 140 ~WaitForThreads() 141 { 142 int result = pthread_cond_destroy( &condition ); 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 assert( result == 0 ); 154 n ++; 155 //~ std::cout << "block() n " << n << " waitFor " << waitFor << std::endl; 156 157 assert( waitFor == 0 || n <= waitFor ); 158 if ( waitFor > 0 && n == waitFor ) 159 { 160 // There are enough threads blocked that we can release all of them 161 std::cout << "Unblocking threads from block()" << std::endl; 162 unblockThreads(); 163 } 164 else 165 { 166 // We just need to wait until someone unblocks us 167 result = pthread_cond_wait( &condition, &mutex ); 168 assert( result == 0 ); 169 } 170 171 // unlock the mutex before returning 172 result = pthread_mutex_unlock( &mutex ); 173 assert( result == 0 ); 174 } 175 176 // If there are num or more threads blocked, it will signal them all 177 // Otherwise, this thread blocks until there are enough OTHER threads 178 // blocked 179 void releaseThreads( size_t num ) 180 { 181 int result = pthread_mutex_lock( &mutex ); 182 assert( result == 0 ); 183 184 if ( n >= num ) { 185 std::cout << "Unblocking threads from releaseThreads()" << std::endl; 186 unblockThreads(); 187 } 188 else 189 { 190 waitFor = num; 191 pthread_cond_wait( &condition, &mutex ); 192 } 193 194 // unlock the mutex before returning 195 result = pthread_mutex_unlock( &mutex ); 196 assert( result == 0 ); 197 } 198 199private: 200 void unblockThreads() 201 { 202 // Reset the counters to zero: this way, if any new threads 203 // enter while threads are exiting, they will block instead 204 // of triggering a new release of threads 205 n = 0; 206 207 // Reset waitFor to zero: this way, if waitFor threads enter 208 // while threads are exiting, they will block instead of 209 // triggering a new release of threads 210 waitFor = 0; 211 212 int result = pthread_cond_broadcast( &condition ); 213 assert(result == 0); result=result; 214 } 215 216 size_t n; 217 size_t waitFor; 218 pthread_cond_t condition; 219 pthread_mutex_t mutex; 220}; 221 222static WaitForThreads synchronize; 223 224void* callFunc( void* param ) 225{ 226 struct threadParams* p = (struct threadParams*) param; 227 228 // Call the `foo' function with no arguments: 229 std::vector<GenericValue> Args(1); 230 Args[0].IntVal = APInt(32, p->value); 231 232 synchronize.block(); // wait until other threads are at this point 233 GenericValue gv = p->EE->runFunction(p->F, Args); 234 235 return (void*)(intptr_t)gv.IntVal.getZExtValue(); 236} 237 238int main() { 239 InitializeNativeTarget(); 240 LLVMContext Context; 241 242 // Create some module to put our function into it. 243 Module *M = new Module("test", Context); 244 245 Function* add1F = createAdd1( M ); 246 Function* fibF = CreateFibFunction( M ); 247 248 // Now we create the JIT. 249 ExecutionEngine* EE = EngineBuilder(M).create(); 250 251 //~ std::cout << "We just constructed this LLVM module:\n\n" << *M; 252 //~ std::cout << "\n\nRunning foo: " << std::flush; 253 254 // Create one thread for add1 and two threads for fib 255 struct threadParams add1 = { EE, add1F, 1000 }; 256 struct threadParams fib1 = { EE, fibF, 39 }; 257 struct threadParams fib2 = { EE, fibF, 42 }; 258 259 pthread_t add1Thread; 260 int result = pthread_create( &add1Thread, NULL, callFunc, &add1 ); 261 if ( result != 0 ) { 262 std::cerr << "Could not create thread" << std::endl; 263 return 1; 264 } 265 266 pthread_t fibThread1; 267 result = pthread_create( &fibThread1, NULL, callFunc, &fib1 ); 268 if ( result != 0 ) { 269 std::cerr << "Could not create thread" << std::endl; 270 return 1; 271 } 272 273 pthread_t fibThread2; 274 result = pthread_create( &fibThread2, NULL, callFunc, &fib2 ); 275 if ( result != 0 ) { 276 std::cerr << "Could not create thread" << std::endl; 277 return 1; 278 } 279 280 synchronize.releaseThreads(3); // wait until other threads are at this point 281 282 void* returnValue; 283 result = pthread_join( add1Thread, &returnValue ); 284 if ( result != 0 ) { 285 std::cerr << "Could not join thread" << std::endl; 286 return 1; 287 } 288 std::cout << "Add1 returned " << intptr_t(returnValue) << std::endl; 289 290 result = pthread_join( fibThread1, &returnValue ); 291 if ( result != 0 ) { 292 std::cerr << "Could not join thread" << std::endl; 293 return 1; 294 } 295 std::cout << "Fib1 returned " << intptr_t(returnValue) << std::endl; 296 297 result = pthread_join( fibThread2, &returnValue ); 298 if ( result != 0 ) { 299 std::cerr << "Could not join thread" << std::endl; 300 return 1; 301 } 302 std::cout << "Fib2 returned " << intptr_t(returnValue) << std::endl; 303 304 return 0; 305} 306