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LLVM Essentials

You're reading from   LLVM Essentials Become familiar with the LLVM infrastructure and start using LLVM libraries to design a compiler

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Product type Paperback
Published in Dec 2015
Publisher
ISBN-13 9781785280801
Length 166 pages
Edition 1st Edition
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Authors (4):
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Suyog Sarda Suyog Sarda
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Suyog Sarda
Mayur Pandey Mayur Pandey
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Mayur Pandey
David Farago David Farago
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David Farago
John Criswell John Criswell
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John Criswell
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Toc

Adding a block to a function


A function consists of basic blocks. A basic block has an entry point. A basic block consists of a number of IR instructions, the last instruction being a terminator instruction. It has single exit point. LLVM provides the BasicBlock class to create and handle basic blocks. A basic block might have an entry point as its label, which indicates where to insert the next instructions. We can use the IRBuilder object to hold these new basic block IR.

BasicBlock *createBB(Function *fooFunc, std::string Name) {
  return BasicBlock::Create(Context, Name, fooFunc);
}

The overall code is as follows:

#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Verifier.h"
#include <vector>
using namespace llvm;

static LLVMContext &Context = getGlobalContext();
static Module *ModuleOb = new Module("my compiler", Context);

Function *createFunc(IRBuilder<> &Builder, std::string Name) {
  FunctionType *funcType...
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