1 //===-- examples/ParallelJIT/ParallelJIT.cpp - Exercise threaded-safe JIT -===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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.
20 #include "llvm/ADT/STLExtras.h"
21 #include "llvm/ExecutionEngine/GenericValue.h"
22 #include "llvm/ExecutionEngine/Interpreter.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"
34 static 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.
39 cast<Function>(M->getOrInsertFunction("add1",
40 Type::getInt32Ty(M->getContext()),
41 Type::getInt32Ty(M->getContext()),
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);
48 // Get pointers to the constant `1'.
49 Value *One = ConstantInt::get(Type::getInt32Ty(M->getContext()), 1);
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.
56 // Create the add instruction, inserting it into the end of BB.
57 Instruction *Add = BinaryOperator::CreateAdd(One, ArgX, "addresult", BB);
59 // Create the return instruction and add it to the basic block
60 ReturnInst::Create(M->getContext(), Add, BB);
62 // Now, function add1 is ready.
66 static 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.
70 cast<Function>(M->getOrInsertFunction("fib",
71 Type::getInt32Ty(M->getContext()),
72 Type::getInt32Ty(M->getContext()),
75 // Add a basic block to the function.
76 BasicBlock *BB = BasicBlock::Create(M->getContext(), "EntryBlock", FibF);
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);
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.
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);
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);
96 ReturnInst::Create(M->getContext(), One, RetBB);
99 Value *Sub = BinaryOperator::CreateSub(ArgX, One, "arg", RecurseBB);
100 Value *CallFibX1 = CallInst::Create(FibF, Sub, "fibx1", RecurseBB);
103 Sub = BinaryOperator::CreateSub(ArgX, Two, "arg", RecurseBB);
104 Value *CallFibX2 = CallInst::Create(FibF, Sub, "fibx2", RecurseBB);
108 BinaryOperator::CreateAdd(CallFibX1, CallFibX2, "addresult", RecurseBB);
110 // Create the return instruction and add it to the basic block
111 ReturnInst::Create(M->getContext(), Sum, RecurseBB);
116 struct threadParams {
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.
133 int result = pthread_cond_init( &condition, nullptr );
134 assert( result == 0 );
136 result = pthread_mutex_init( &mutex, nullptr );
137 assert( result == 0 );
142 int result = pthread_cond_destroy( &condition );
144 assert( result == 0 );
146 result = pthread_mutex_destroy( &mutex );
147 assert( result == 0 );
150 // All threads will stop here until another thread calls releaseThreads
153 int result = pthread_mutex_lock( &mutex );
155 assert( result == 0 );
157 //~ std::cout << "block() n " << n << " waitFor " << waitFor << std::endl;
159 assert( waitFor == 0 || n <= waitFor );
160 if ( waitFor > 0 && n == waitFor )
162 // There are enough threads blocked that we can release all of them
163 std::cout << "Unblocking threads from block()" << std::endl;
168 // We just need to wait until someone unblocks us
169 result = pthread_cond_wait( &condition, &mutex );
170 assert( result == 0 );
173 // unlock the mutex before returning
174 result = pthread_mutex_unlock( &mutex );
175 assert( result == 0 );
178 // If there are num or more threads blocked, it will signal them all
179 // Otherwise, this thread blocks until there are enough OTHER threads
181 void releaseThreads( size_t num )
183 int result = pthread_mutex_lock( &mutex );
185 assert( result == 0 );
188 std::cout << "Unblocking threads from releaseThreads()" << std::endl;
194 pthread_cond_wait( &condition, &mutex );
197 // unlock the mutex before returning
198 result = pthread_mutex_unlock( &mutex );
199 assert( result == 0 );
203 void unblockThreads()
205 // Reset the counters to zero: this way, if any new threads
206 // enter while threads are exiting, they will block instead
207 // of triggering a new release of threads
210 // Reset waitFor to zero: this way, if waitFor threads enter
211 // while threads are exiting, they will block instead of
212 // triggering a new release of threads
215 int result = pthread_cond_broadcast( &condition );
222 pthread_cond_t condition;
223 pthread_mutex_t mutex;
226 static WaitForThreads synchronize;
228 void* callFunc( void* param )
230 struct threadParams* p = (struct threadParams*) param;
232 // Call the `foo' function with no arguments:
233 std::vector<GenericValue> Args(1);
234 Args[0].IntVal = APInt(32, p->value);
236 synchronize.block(); // wait until other threads are at this point
237 GenericValue gv = p->EE->runFunction(p->F, Args);
239 return (void*)(intptr_t)gv.IntVal.getZExtValue();
243 InitializeNativeTarget();
246 // Create some module to put our function into it.
247 std::unique_ptr<Module> Owner = make_unique<Module>("test", Context);
248 Module *M = Owner.get();
250 Function* add1F = createAdd1( M );
251 Function* fibF = CreateFibFunction( M );
253 // Now we create the JIT.
254 ExecutionEngine* EE = EngineBuilder(std::move(Owner)).create();
256 //~ std::cout << "We just constructed this LLVM module:\n\n" << *M;
257 //~ std::cout << "\n\nRunning foo: " << std::flush;
259 // Create one thread for add1 and two threads for fib
260 struct threadParams add1 = { EE, add1F, 1000 };
261 struct threadParams fib1 = { EE, fibF, 39 };
262 struct threadParams fib2 = { EE, fibF, 42 };
264 pthread_t add1Thread;
265 int result = pthread_create( &add1Thread, nullptr, callFunc, &add1 );
267 std::cerr << "Could not create thread" << std::endl;
271 pthread_t fibThread1;
272 result = pthread_create( &fibThread1, nullptr, callFunc, &fib1 );
274 std::cerr << "Could not create thread" << std::endl;
278 pthread_t fibThread2;
279 result = pthread_create( &fibThread2, nullptr, callFunc, &fib2 );
281 std::cerr << "Could not create thread" << std::endl;
285 synchronize.releaseThreads(3); // wait until other threads are at this point
288 result = pthread_join( add1Thread, &returnValue );
290 std::cerr << "Could not join thread" << std::endl;
293 std::cout << "Add1 returned " << intptr_t(returnValue) << std::endl;
295 result = pthread_join( fibThread1, &returnValue );
297 std::cerr << "Could not join thread" << std::endl;
300 std::cout << "Fib1 returned " << intptr_t(returnValue) << std::endl;
302 result = pthread_join( fibThread2, &returnValue );
304 std::cerr << "Could not join thread" << std::endl;
307 std::cout << "Fib2 returned " << intptr_t(returnValue) << std::endl;