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Diffstat (limited to 'examples/HowToUseJIT')
| -rw-r--r-- | examples/HowToUseJIT/HowToUseJIT.cpp | 153 | ||||
| -rw-r--r-- | examples/HowToUseJIT/Makefile | 15 |
2 files changed, 168 insertions, 0 deletions
diff --git a/examples/HowToUseJIT/HowToUseJIT.cpp b/examples/HowToUseJIT/HowToUseJIT.cpp new file mode 100644 index 0000000000..821f7beec8 --- /dev/null +++ b/examples/HowToUseJIT/HowToUseJIT.cpp @@ -0,0 +1,153 @@ +//===--- 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 tool provides a single point of access to the LLVM compilation tools. +// It has many options. To discover the options supported please refer to the +// tools' manual page (docs/CommandGuide/html/llvmc.html) or run the tool with +// the --help option. +// +//===------------------------------------------------------------------------=== + +// Goal: +// The goal of this snippet is to create in the memory +// 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' +// 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 +// 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/ExecutionEngine/GenericValue.h" + + +using namespace llvm; + +int main() { + + // 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); + + // Get pointers to the constant `1'... + Value *One = ConstantSInt::get(Type::IntTy, 1); + + // 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 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 ); + + // 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; + + return 0; +} diff --git a/examples/HowToUseJIT/Makefile b/examples/HowToUseJIT/Makefile new file mode 100644 index 0000000000..834ad02e3c --- /dev/null +++ b/examples/HowToUseJIT/Makefile @@ -0,0 +1,15 @@ +##===- projects/HowToUseJIT/Makefile -----------------------*- Makefile -*-===## +# +# 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. +# +##===----------------------------------------------------------------------===## +LEVEL = ../.. +TOOLNAME = HowToUseJIT +USEDLIBS = lli-jit lli-interpreter codegen executionengine x86 selectiondag \ + scalaropts analysis.a transformutils.a bcreader target.a vmcore \ + support.a + +include $(LEVEL)/Makefile.common |