llvm-6502/include/llvm/Support/MDBuilder.h
2012-04-15 18:03:49 +00:00

102 lines
3.7 KiB
C++

//===---- llvm/Support/MDBuilder.h - Builder for LLVM metadata --*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the MDBuilder class, which is used as a convenient way to
// create LLVM metadata with a consistent and simplified interface.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_MDBUILDER_H
#define LLVM_SUPPORT_MDBUILDER_H
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/LLVMContext.h"
#include "llvm/Metadata.h"
#include "llvm/ADT/APInt.h"
namespace llvm {
class MDBuilder {
LLVMContext &Context;
public:
MDBuilder(LLVMContext &context) : Context(context) {}
/// CreateString - Return the given string as metadata.
MDString *CreateString(StringRef Str) const {
return MDString::get(Context, Str);
}
//===------------------------------------------------------------------===//
// Range metadata.
//===------------------------------------------------------------------===//
/// CreateRange - Return metadata describing the range [Lo, Hi).
MDNode *CreateRange(const APInt &Lo, const APInt &Hi) const {
assert(Lo.getBitWidth() == Hi.getBitWidth() && "Mismatched bitwidths!");
// If the range is everything then it is useless.
if (Hi == Lo)
return 0;
// Return the range [Lo, Hi).
Type *Ty = IntegerType::get(Context, Lo.getBitWidth());
Value *Range[2] = { ConstantInt::get(Ty, Lo), ConstantInt::get(Ty, Hi) };
return MDNode::get(Context, Range);
}
//===------------------------------------------------------------------===//
// TBAA metadata.
//===------------------------------------------------------------------===//
/// CreateAnonymousTBAARoot - Return metadata appropriate for a TBAA root
/// node. Each returned node is distinct from all other metadata and will
/// never be identified (uniqued) with anything else.
MDNode *CreateAnonymousTBAARoot() const {
// To ensure uniqueness the root node is self-referential.
MDNode *Dummy = MDNode::getTemporary(Context, ArrayRef<Value*>());
MDNode *Root = MDNode::get(Context, Dummy);
// At this point we have
// !0 = metadata !{} <- dummy
// !1 = metadata !{metadata !0} <- root
// Replace the dummy operand with the root node itself and delete the dummy.
Root->replaceOperandWith(0, Root);
MDNode::deleteTemporary(Dummy);
// We now have
// !1 = metadata !{metadata !1} <- self-referential root
return Root;
}
/// CreateTBAARoot - Return metadata appropriate for a TBAA root node with
/// the given name. This may be identified (uniqued) with other roots with
/// the same name.
MDNode *CreateTBAARoot(StringRef Name) const {
return MDNode::get(Context, CreateString(Name));
}
/// CreateTBAANode - Return metadata for a non-root TBAA node with the given
/// name, parent in the TBAA tree, and value for 'pointsToConstantMemory'.
MDNode *CreateTBAANode(StringRef Name, MDNode *Parent,
bool isConstant = false) const {
if (isConstant) {
Constant *Flags = ConstantInt::get(Type::getInt64Ty(Context), 1);
Value *Ops[3] = { CreateString(Name), Parent, Flags };
return MDNode::get(Context, Ops);
} else {
Value *Ops[2] = { CreateString(Name), Parent };
return MDNode::get(Context, Ops);
}
}
};
} // end namespace llvm
#endif