1 //===- MCAsmLayout.h - Assembly Layout Object -------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #ifndef LLVM_MC_MCASMLAYOUT_H
11 #define LLVM_MC_MCASMLAYOUT_H
13 #include "llvm/ADT/DenseMap.h"
14 #include "llvm/ADT/SmallVector.h"
22 /// Encapsulates the layout of an assembly file at a particular point in time.
24 /// Assembly may require computing multiple layouts for a particular assembly
25 /// file as part of the relaxation process. This class encapsulates the layout
26 /// at a single point in time in such a way that it is always possible to
27 /// efficiently compute the exact address of any symbol in the assembly file,
28 /// even during the relaxation process.
31 typedef llvm::SmallVectorImpl<MCSectionData*>::const_iterator const_iterator;
32 typedef llvm::SmallVectorImpl<MCSectionData*>::iterator iterator;
35 MCAssembler &Assembler;
37 /// List of sections in layout order.
38 llvm::SmallVector<MCSectionData*, 16> SectionOrder;
40 /// The last fragment which was laid out, or 0 if nothing has been laid
41 /// out. Fragments are always laid out in order, so all fragments with a
42 /// lower ordinal will be valid.
43 mutable DenseMap<const MCSectionData*, MCFragment*> LastValidFragment;
45 /// \brief Make sure that the layout for the given fragment is valid, lazily
46 /// computing it if necessary.
47 void ensureValid(const MCFragment *F) const;
49 /// \brief Is the layout for this fragment valid?
50 bool isFragmentValid(const MCFragment *F) const;
52 /// \brief Compute the amount of padding required before this fragment to
53 /// obey bundling restrictions.
54 uint64_t computeBundlePadding(const MCFragment *F,
55 uint64_t FOffset, uint64_t FSize);
58 MCAsmLayout(MCAssembler &_Assembler);
60 /// Get the assembler object this is a layout for.
61 MCAssembler &getAssembler() const { return Assembler; }
63 /// \brief Invalidate the fragments starting with F because it has been
64 /// resized. The fragment's size should have already been updated, but
65 /// its bundle padding will be recomputed.
66 void invalidateFragmentsFrom(MCFragment *F);
68 /// \brief Perform layout for a single fragment, assuming that the previous
69 /// fragment has already been laid out correctly, and the parent section has
71 void layoutFragment(MCFragment *Fragment);
73 /// @name Section Access (in layout order)
76 llvm::SmallVectorImpl<MCSectionData*> &getSectionOrder() {
79 const llvm::SmallVectorImpl<MCSectionData*> &getSectionOrder() const {
84 /// @name Fragment Layout Data
87 /// \brief Get the offset of the given fragment inside its containing section.
88 uint64_t getFragmentOffset(const MCFragment *F) const;
91 /// @name Utility Functions
94 /// \brief Get the address space size of the given section, as it effects
95 /// layout. This may differ from the size reported by \see getSectionSize() by
96 /// not including section tail padding.
97 uint64_t getSectionAddressSize(const MCSectionData *SD) const;
99 /// \brief Get the data size of the given section, as emitted to the object
100 /// file. This may include additional padding, or be 0 for virtual sections.
101 uint64_t getSectionFileSize(const MCSectionData *SD) const;
103 /// \brief Get the offset of the given symbol, as computed in the current
105 uint64_t getSymbolOffset(const MCSymbolData *SD) const;
110 } // end namespace llvm