mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-25 12:12:47 +01:00
a38c737e85
pointer marking the end of the list, the zero *must* be cast to the pointer type. An un-cast zero is a 32-bit int, and at least on x86_64, gcc will not extend the zero to 64 bits, thus allowing the upper 32 bits to be random junk. The new END_WITH_NULL macro may be used to annotate a such a function so that GCC (version 4 or newer) will detect the use of un-casted zero at compile time. llvm-svn: 23888
120 lines
3.9 KiB
C++
120 lines
3.9 KiB
C++
//===--- examples/Fibonacci/fibonacci.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 small program provides an example of how to build quickly a small module
|
|
// with function Fibonacci and execute it with the JIT.
|
|
//
|
|
// The goal of this snippet is to create in the memory the LLVM module
|
|
// consisting of one function as follow:
|
|
//
|
|
// int fib(int x) {
|
|
// if(x<=2) return 1;
|
|
// return fib(x-1)+fib(x-2);
|
|
// }
|
|
//
|
|
// Once we have this, we compile the module via JIT, then execute the `fib'
|
|
// function and return result to a driver, i.e. to a "host program".
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/Module.h"
|
|
#include "llvm/DerivedTypes.h"
|
|
#include "llvm/Constants.h"
|
|
#include "llvm/Instructions.h"
|
|
#include "llvm/ModuleProvider.h"
|
|
#include "llvm/Analysis/Verifier.h"
|
|
#include "llvm/ExecutionEngine/ExecutionEngine.h"
|
|
#include "llvm/ExecutionEngine/GenericValue.h"
|
|
#include <iostream>
|
|
using namespace llvm;
|
|
|
|
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 = M->getOrInsertFunction("fib", Type::IntTy, Type::IntTy,
|
|
(Type *)0);
|
|
|
|
// Add a basic block to the function.
|
|
BasicBlock *BB = new BasicBlock("EntryBlock", FibF);
|
|
|
|
// Get pointers to the constants.
|
|
Value *One = ConstantSInt::get(Type::IntTy, 1);
|
|
Value *Two = ConstantSInt::get(Type::IntTy, 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 = new BasicBlock("return", FibF);
|
|
// Create an exit block.
|
|
BasicBlock* RecurseBB = new BasicBlock("recurse", FibF);
|
|
|
|
// Create the "if (arg < 2) goto exitbb"
|
|
Value *CondInst = BinaryOperator::createSetLE(ArgX, Two, "cond", BB);
|
|
new BranchInst(RetBB, RecurseBB, CondInst, BB);
|
|
|
|
// Create: ret int 1
|
|
new ReturnInst(One, RetBB);
|
|
|
|
// create fib(x-1)
|
|
Value *Sub = BinaryOperator::createSub(ArgX, One, "arg", RecurseBB);
|
|
CallInst *CallFibX1 = new CallInst(FibF, Sub, "fibx1", RecurseBB);
|
|
CallFibX1->setTailCall();
|
|
|
|
// create fib(x-2)
|
|
Sub = BinaryOperator::createSub(ArgX, Two, "arg", RecurseBB);
|
|
CallInst *CallFibX2 = new CallInst(FibF, Sub, "fibx2", RecurseBB);
|
|
CallFibX2->setTailCall();
|
|
|
|
|
|
// 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
|
|
new ReturnInst(Sum, RecurseBB);
|
|
|
|
return FibF;
|
|
}
|
|
|
|
|
|
int main(int argc, char **argv) {
|
|
int n = argc > 1 ? atol(argv[1]) : 24;
|
|
|
|
// Create some module to put our function into it.
|
|
Module *M = new Module("test");
|
|
|
|
// We are about to create the "fib" function:
|
|
Function *FibF = CreateFibFunction(M);
|
|
|
|
// Now we going to create JIT
|
|
ExistingModuleProvider *MP = new ExistingModuleProvider(M);
|
|
ExecutionEngine *EE = ExecutionEngine::create(MP, false);
|
|
|
|
std::cerr << "verifying... ";
|
|
if (verifyModule(*M)) {
|
|
std::cerr << argv[0] << ": Error constructing function!\n";
|
|
return 1;
|
|
}
|
|
|
|
std::cerr << "OK\n";
|
|
std::cerr << "We just constructed this LLVM module:\n\n---------\n" << *M;
|
|
std::cerr << "---------\nstarting fibonacci(" << n << ") with JIT...\n";
|
|
|
|
// Call the Fibonacci function with argument n:
|
|
std::vector<GenericValue> Args(1);
|
|
Args[0].IntVal = n;
|
|
GenericValue GV = EE->runFunction(FibF, Args);
|
|
|
|
// import result of execution
|
|
std::cout << "Result: " << GV.IntVal << "\n";
|
|
return 0;
|
|
}
|