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llvm-mirror/include/llvm/MC/MCAsmLayout.h
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

107 lines
3.6 KiB
C++

//===- MCAsmLayout.h - Assembly Layout Object -------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_MC_MCASMLAYOUT_H
#define LLVM_MC_MCASMLAYOUT_H
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
namespace llvm {
class MCAssembler;
class MCFragment;
class MCSection;
class MCSymbol;
/// Encapsulates the layout of an assembly file at a particular point in time.
///
/// Assembly may require computing multiple layouts for a particular assembly
/// file as part of the relaxation process. This class encapsulates the layout
/// at a single point in time in such a way that it is always possible to
/// efficiently compute the exact address of any symbol in the assembly file,
/// even during the relaxation process.
class MCAsmLayout {
MCAssembler &Assembler;
/// List of sections in layout order.
llvm::SmallVector<MCSection *, 16> SectionOrder;
/// The last fragment which was laid out, or 0 if nothing has been laid
/// out. Fragments are always laid out in order, so all fragments with a
/// lower ordinal will be valid.
mutable DenseMap<const MCSection *, MCFragment *> LastValidFragment;
/// Make sure that the layout for the given fragment is valid, lazily
/// computing it if necessary.
void ensureValid(const MCFragment *F) const;
/// Is the layout for this fragment valid?
bool isFragmentValid(const MCFragment *F) const;
public:
MCAsmLayout(MCAssembler &Assembler);
/// Get the assembler object this is a layout for.
MCAssembler &getAssembler() const { return Assembler; }
/// Invalidate the fragments starting with F because it has been
/// resized. The fragment's size should have already been updated, but
/// its bundle padding will be recomputed.
void invalidateFragmentsFrom(MCFragment *F);
/// Perform layout for a single fragment, assuming that the previous
/// fragment has already been laid out correctly, and the parent section has
/// been initialized.
void layoutFragment(MCFragment *Fragment);
/// \name Section Access (in layout order)
/// @{
llvm::SmallVectorImpl<MCSection *> &getSectionOrder() { return SectionOrder; }
const llvm::SmallVectorImpl<MCSection *> &getSectionOrder() const {
return SectionOrder;
}
/// @}
/// \name Fragment Layout Data
/// @{
/// Get the offset of the given fragment inside its containing section.
uint64_t getFragmentOffset(const MCFragment *F) const;
/// @}
/// \name Utility Functions
/// @{
/// Get the address space size of the given section, as it effects
/// layout. This may differ from the size reported by \see getSectionSize() by
/// not including section tail padding.
uint64_t getSectionAddressSize(const MCSection *Sec) const;
/// Get the data size of the given section, as emitted to the object
/// file. This may include additional padding, or be 0 for virtual sections.
uint64_t getSectionFileSize(const MCSection *Sec) const;
/// Get the offset of the given symbol, as computed in the current
/// layout.
/// \return True on success.
bool getSymbolOffset(const MCSymbol &S, uint64_t &Val) const;
/// Variant that reports a fatal error if the offset is not computable.
uint64_t getSymbolOffset(const MCSymbol &S) const;
/// If this symbol is equivalent to A + Constant, return A.
const MCSymbol *getBaseSymbol(const MCSymbol &Symbol) const;
/// @}
};
} // end namespace llvm
#endif