//===-- examples/ParallelJIT/ParallelJIT.cpp - Exercise threaded-safe JIT -===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // Parallel JIT // // This test program creates two LLVM functions then calls them from three // separate threads. It requires the pthreads library. // The three threads are created and then block waiting on a condition variable. // Once all threads are blocked on the conditional variable, the main thread // wakes them up. This complicated work is performed so that all three threads // call into the JIT at the same time (or the best possible approximation of the // same time). This test had assertion errors until I got the locking right. #include "llvm/ExecutionEngine/GenericValue.h" #include "llvm/ExecutionEngine/Interpreter.h" #include "llvm/ExecutionEngine/JIT.h" #include "llvm/IR/Constants.h" #include "llvm/IR/DerivedTypes.h" #include "llvm/IR/Instructions.h" #include "llvm/IR/LLVMContext.h" #include "llvm/IR/Module.h" #include "llvm/Support/TargetSelect.h" #include <iostream> #include <pthread.h> using namespace llvm; static Function* createAdd1(Module *M) { // Create the add1 function entry and insert this entry into module M. The // function will have a return type of "int" and take an argument of "int". // The '0' terminates the list of argument types. Function *Add1F = cast<Function>(M->getOrInsertFunction("add1", Type::getInt32Ty(M->getContext()), Type::getInt32Ty(M->getContext()), (Type *)0)); // Add a basic block to the function. As before, it automatically inserts // because of the last argument. BasicBlock *BB = BasicBlock::Create(M->getContext(), "EntryBlock", Add1F); // Get pointers to the constant `1'. Value *One = ConstantInt::get(Type::getInt32Ty(M->getContext()), 1); // Get pointers to the integer argument of the add1 function... assert(Add1F->arg_begin() != Add1F->arg_end()); // Make sure there's an arg Argument *ArgX = Add1F->arg_begin(); // Get the arg ArgX->setName("AnArg"); // Give it a nice symbolic name for fun. // Create the add instruction, inserting it into the end of BB. Instruction *Add = BinaryOperator::CreateAdd(One, ArgX, "addresult", BB); // Create the return instruction and add it to the basic block ReturnInst::Create(M->getContext(), Add, BB); // Now, function add1 is ready. return Add1F; } static Function *CreateFibFunction(Module *M) { // Create the fib function and insert it into module M. This function is said // to return an int and take an int parameter. Function *FibF = cast<Function>(M->getOrInsertFunction("fib", Type::getInt32Ty(M->getContext()), Type::getInt32Ty(M->getContext()), (Type *)0)); // Add a basic block to the function. BasicBlock *BB = BasicBlock::Create(M->getContext(), "EntryBlock", FibF); // Get pointers to the constants. Value *One = ConstantInt::get(Type::getInt32Ty(M->getContext()), 1); Value *Two = ConstantInt::get(Type::getInt32Ty(M->getContext()), 2); // Get pointer to the integer argument of the add1 function... Argument *ArgX = FibF->arg_begin(); // Get the arg. ArgX->setName("AnArg"); // Give it a nice symbolic name for fun. // Create the true_block. BasicBlock *RetBB = BasicBlock::Create(M->getContext(), "return", FibF); // Create an exit block. BasicBlock* RecurseBB = BasicBlock::Create(M->getContext(), "recurse", FibF); // Create the "if (arg < 2) goto exitbb" Value *CondInst = new ICmpInst(*BB, ICmpInst::ICMP_SLE, ArgX, Two, "cond"); BranchInst::Create(RetBB, RecurseBB, CondInst, BB); // Create: ret int 1 ReturnInst::Create(M->getContext(), One, RetBB); // create fib(x-1) Value *Sub = BinaryOperator::CreateSub(ArgX, One, "arg", RecurseBB); Value *CallFibX1 = CallInst::Create(FibF, Sub, "fibx1", RecurseBB); // create fib(x-2) Sub = BinaryOperator::CreateSub(ArgX, Two, "arg", RecurseBB); Value *CallFibX2 = CallInst::Create(FibF, Sub, "fibx2", RecurseBB); // fib(x-1)+fib(x-2) Value *Sum = BinaryOperator::CreateAdd(CallFibX1, CallFibX2, "addresult", RecurseBB); // Create the return instruction and add it to the basic block ReturnInst::Create(M->getContext(), Sum, RecurseBB); return FibF; } struct threadParams { ExecutionEngine* EE; Function* F; int value; }; // We block the subthreads just before they begin to execute: // we want all of them to call into the JIT at the same time, // to verify that the locking is working correctly. class WaitForThreads { public: WaitForThreads() { n = 0; waitFor = 0; int result = pthread_cond_init( &condition, NULL ); assert( result == 0 ); result = pthread_mutex_init( &mutex, NULL ); assert( result == 0 ); } ~WaitForThreads() { int result = pthread_cond_destroy( &condition ); assert( result == 0 ); result = pthread_mutex_destroy( &mutex ); assert( result == 0 ); } // All threads will stop here until another thread calls releaseThreads void block() { int result = pthread_mutex_lock( &mutex ); assert( result == 0 ); n ++; //~ std::cout << "block() n " << n << " waitFor " << waitFor << std::endl; assert( waitFor == 0 || n <= waitFor ); if ( waitFor > 0 && n == waitFor ) { // There are enough threads blocked that we can release all of them std::cout << "Unblocking threads from block()" << std::endl; unblockThreads(); } else { // We just need to wait until someone unblocks us result = pthread_cond_wait( &condition, &mutex ); assert( result == 0 ); } // unlock the mutex before returning result = pthread_mutex_unlock( &mutex ); assert( result == 0 ); } // If there are num or more threads blocked, it will signal them all // Otherwise, this thread blocks until there are enough OTHER threads // blocked void releaseThreads( size_t num ) { int result = pthread_mutex_lock( &mutex ); assert( result == 0 ); if ( n >= num ) { std::cout << "Unblocking threads from releaseThreads()" << std::endl; unblockThreads(); } else { waitFor = num; pthread_cond_wait( &condition, &mutex ); } // unlock the mutex before returning result = pthread_mutex_unlock( &mutex ); assert( result == 0 ); } private: void unblockThreads() { // Reset the counters to zero: this way, if any new threads // enter while threads are exiting, they will block instead // of triggering a new release of threads n = 0; // Reset waitFor to zero: this way, if waitFor threads enter // while threads are exiting, they will block instead of // triggering a new release of threads waitFor = 0; int result = pthread_cond_broadcast( &condition ); (void)result; assert(result == 0); } size_t n; size_t waitFor; pthread_cond_t condition; pthread_mutex_t mutex; }; static WaitForThreads synchronize; void* callFunc( void* param ) { struct threadParams* p = (struct threadParams*) param; // Call the `foo' function with no arguments: std::vector<GenericValue> Args(1); Args[0].IntVal = APInt(32, p->value); synchronize.block(); // wait until other threads are at this point GenericValue gv = p->EE->runFunction(p->F, Args); return (void*)(intptr_t)gv.IntVal.getZExtValue(); } int main() { InitializeNativeTarget(); LLVMContext Context; // Create some module to put our function into it. Module *M = new Module("test", Context); Function* add1F = createAdd1( M ); Function* fibF = CreateFibFunction( M ); // Now we create the JIT. ExecutionEngine* EE = EngineBuilder(M).create(); //~ std::cout << "We just constructed this LLVM module:\n\n" << *M; //~ std::cout << "\n\nRunning foo: " << std::flush; // Create one thread for add1 and two threads for fib struct threadParams add1 = { EE, add1F, 1000 }; struct threadParams fib1 = { EE, fibF, 39 }; struct threadParams fib2 = { EE, fibF, 42 }; pthread_t add1Thread; int result = pthread_create( &add1Thread, NULL, callFunc, &add1 ); if ( result != 0 ) { std::cerr << "Could not create thread" << std::endl; return 1; } pthread_t fibThread1; result = pthread_create( &fibThread1, NULL, callFunc, &fib1 ); if ( result != 0 ) { std::cerr << "Could not create thread" << std::endl; return 1; } pthread_t fibThread2; result = pthread_create( &fibThread2, NULL, callFunc, &fib2 ); if ( result != 0 ) { std::cerr << "Could not create thread" << std::endl; return 1; } synchronize.releaseThreads(3); // wait until other threads are at this point void* returnValue; result = pthread_join( add1Thread, &returnValue ); if ( result != 0 ) { std::cerr << "Could not join thread" << std::endl; return 1; } std::cout << "Add1 returned " << intptr_t(returnValue) << std::endl; result = pthread_join( fibThread1, &returnValue ); if ( result != 0 ) { std::cerr << "Could not join thread" << std::endl; return 1; } std::cout << "Fib1 returned " << intptr_t(returnValue) << std::endl; result = pthread_join( fibThread2, &returnValue ); if ( result != 0 ) { std::cerr << "Could not join thread" << std::endl; return 1; } std::cout << "Fib2 returned " << intptr_t(returnValue) << std::endl; return 0; }