-//===--- HowToUseJIT.cpp - An example use of the JIT ----------------------===//
-//
+//===-- examples/HowToUseJIT/HowToUseJIT.cpp - An example use of the JIT --===//
+//
// The LLVM Compiler Infrastructure
//
-// This file was developed by Valery A. Khamenya and is distributed under the
-// University of Illinois Open Source License. See LICENSE.TXT for details.
-//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
//===----------------------------------------------------------------------===//
//
// This small program provides an example of how to quickly build a small
-// module with two functions and execute it with the JIT.
-//
-//===------------------------------------------------------------------------===
-
-// Goal:
+// module with two functions and execute it with the JIT.
+//
+// Goal:
// The goal of this snippet is to create in the memory
-// the LLVM module consisting of two functions as follow:
+// the LLVM module consisting of two functions as follow:
//
// int add1(int x) {
// return x+1;
// }
-//
+//
// int foo() {
// return add1(10);
// }
-//
-// then compile the module via JIT, then execute the `foo'
+//
+// then compile the module via JIT, then execute the `foo'
// function and return result to a driver, i.e. to a "host program".
-//
+//
// Some remarks and questions:
-//
+//
// - could we invoke some code using noname functions too?
-// e.g. evaluate "foo()+foo()" without fears to introduce
+// e.g. evaluate "foo()+foo()" without fears to introduce
// conflict of temporary function name with some real
// existing function name?
-//
-
-#include <iostream>
-
-#include <llvm/Module.h>
-#include <llvm/DerivedTypes.h>
-#include <llvm/Constants.h>
-#include <llvm/Instructions.h>
-#include <llvm/ModuleProvider.h>
+//
+//===----------------------------------------------------------------------===//
-#include "llvm/ExecutionEngine/ExecutionEngine.h"
+#include "llvm/ADT/STLExtras.h"
#include "llvm/ExecutionEngine/GenericValue.h"
-
+#include "llvm/ExecutionEngine/Interpreter.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/raw_ostream.h"
using namespace llvm;
int main() {
+
+ InitializeNativeTarget();
- // Create some module to put our function into it.
- Module *M = new Module("test");
-
-
- // We are about to create the add1 function:
- Function *Add1F;
-
- {
- // first create type for the single argument of add1 function:
- // the type is 'int ()'
- std::vector<const Type*> ArgT(1);
- ArgT[0] = Type::IntTy;
-
- // now create full type of the add1 function:
- FunctionType *Add1T = FunctionType::get(Type::IntTy, // type of result
- ArgT,
- /*not vararg*/false);
-
- // Now create the add1 function entry and
- // insert this entry into module M
- // (By passing a module as the last parameter to the Function constructor,
- // it automatically gets appended to the Module.)
- Add1F = new Function(Add1T,
- Function::ExternalLinkage, // maybe too much
- "add1", M);
-
- // Add a basic block to the function... (again, it automatically inserts
- // because of the last argument.)
- BasicBlock *BB = new BasicBlock("EntryBlock of add1 function", Add1F);
+ LLVMContext Context;
- // Get pointers to the constant `1'...
- Value *One = ConstantSInt::get(Type::IntTy, 1);
+ // Create some module to put our function into it.
+ std::unique_ptr<Module> Owner = make_unique<Module>("test", Context);
+ Module *M = Owner.get();
- // Get pointers to the integer argument of the add1 function...
- assert(Add1F->abegin() != Add1F->aend()); // Make sure there's an arg
- Argument &ArgX = Add1F->afront(); // Get the arg
+ // 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(Context),
+ Type::getInt32Ty(Context),
+ nullptr));
- // Create the add instruction... does not insert...
- Instruction *Add = BinaryOperator::create(Instruction::Add, One, &ArgX,
- "addresult");
-
- // explicitly insert it into the basic block...
- BB->getInstList().push_back(Add);
-
- // Create the return instruction and add it to the basic block
- BB->getInstList().push_back(new ReturnInst(Add));
-
- // function add1 is ready
- }
-
-
- // now we going to create function `foo':
- Function *FooF;
-
- {
- // Create the foo function type:
- FunctionType *FooT =
- FunctionType::get(Type::IntTy, // result has type: 'int ()'
- std::vector<const Type*>(), // no arguments
- /*not vararg*/false);
-
- // create the entry for function `foo' and insert
- // this entry into module M:
- FooF =
- new Function(FooT,
- Function::ExternalLinkage, // too wide?
- "foo", M);
-
- // Add a basic block to the FooF function...
- BasicBlock *BB = new BasicBlock("EntryBlock of add1 function", FooF);
-
- // Get pointers to the constant `10'...
- Value *Ten = ConstantSInt::get(Type::IntTy, 10);
-
- // Put the argument Ten on stack and make call:
- // ...
- std::vector<Value*> Params;
- Params.push_back(Ten);
- CallInst * Add1CallRes = new CallInst(Add1F, Params, "add1", BB);
-
- // Create the return instruction and add it to the basic block
- BB->getInstList().push_back(new ReturnInst(Add1CallRes));
-
- }
-
- // Now we going to create JIT ??
- ExistingModuleProvider* MP = new ExistingModuleProvider(M);
- ExecutionEngine* EE = ExecutionEngine::create( MP, true );
+ // Add a basic block to the function. As before, it automatically inserts
+ // because of the last argument.
+ BasicBlock *BB = BasicBlock::Create(Context, "EntryBlock", Add1F);
+
+ // Create a basic block builder with default parameters. The builder will
+ // automatically append instructions to the basic block `BB'.
+ IRBuilder<> builder(BB);
+
+ // Get pointers to the constant `1'.
+ Value *One = builder.getInt32(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.
+ Value *Add = builder.CreateAdd(One, ArgX);
+
+ // Create the return instruction and add it to the basic block
+ builder.CreateRet(Add);
+
+ // Now, function add1 is ready.
+
+ // Now we're going to create function `foo', which returns an int and takes no
+ // arguments.
+ Function *FooF =
+ cast<Function>(M->getOrInsertFunction("foo", Type::getInt32Ty(Context),
+ nullptr));
+
+ // Add a basic block to the FooF function.
+ BB = BasicBlock::Create(Context, "EntryBlock", FooF);
+
+ // Tell the basic block builder to attach itself to the new basic block
+ builder.SetInsertPoint(BB);
+
+ // Get pointer to the constant `10'.
+ Value *Ten = builder.getInt32(10);
+
+ // Pass Ten to the call to Add1F
+ CallInst *Add1CallRes = builder.CreateCall(Add1F, Ten);
+ Add1CallRes->setTailCall(true);
+
+ // Create the return instruction and add it to the basic block.
+ builder.CreateRet(Add1CallRes);
+
+ // Now we create the JIT.
+ ExecutionEngine* EE = EngineBuilder(std::move(Owner)).create();
+
+ outs() << "We just constructed this LLVM module:\n\n" << *M;
+ outs() << "\n\nRunning foo: ";
+ outs().flush();
// Call the `foo' function with no arguments:
std::vector<GenericValue> noargs;
GenericValue gv = EE->runFunction(FooF, noargs);
- // import result of execution:
- std::cout << "Result: " << gv.IntVal << std:: endl;
-
+ // Import result of execution:
+ outs() << "Result: " << gv.IntVal << "\n";
+ delete EE;
+ llvm_shutdown();
return 0;
}
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