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"
23 /// Encapsulates the layout of an assembly file at a particular point in time.
25 /// Assembly may require computing multiple layouts for a particular assembly
26 /// file as part of the relaxation process. This class encapsulates the layout
27 /// at a single point in time in such a way that it is always possible to
28 /// efficiently compute the exact address of any symbol in the assembly file,
29 /// even during the relaxation process.
32 typedef llvm::SmallVectorImpl<MCSectionData*>::const_iterator const_iterator;
33 typedef llvm::SmallVectorImpl<MCSectionData*>::iterator iterator;
36 MCAssembler &Assembler;
38 /// List of sections in layout order.
39 llvm::SmallVector<MCSectionData*, 16> SectionOrder;
41 /// The last fragment which was laid out, or 0 if nothing has been laid
42 /// out. Fragments are always laid out in order, so all fragments with a
43 /// lower ordinal will be valid.
44 mutable DenseMap<const MCSectionData*, MCFragment*> LastValidFragment;
46 /// \brief Make sure that the layout for the given fragment is valid, lazily
47 /// computing it if necessary.
48 void ensureValid(const MCFragment *F) const;
50 /// \brief Is the layout for this fragment valid?
51 bool isFragmentValid(const MCFragment *F) const;
53 /// \brief Compute the amount of padding required before this fragment to
54 /// obey bundling restrictions.
55 uint64_t computeBundlePadding(const MCFragment *F,
56 uint64_t FOffset, uint64_t FSize);
59 MCAsmLayout(MCAssembler &_Assembler);
61 /// Get the assembler object this is a layout for.
62 MCAssembler &getAssembler() const { return Assembler; }
64 /// \brief Invalidate the fragments starting with F because it has been
65 /// resized. The fragment's size should have already been updated, but
66 /// its bundle padding will be recomputed.
67 void invalidateFragmentsFrom(MCFragment *F);
69 /// \brief Perform layout for a single fragment, assuming that the previous
70 /// fragment has already been laid out correctly, and the parent section has
72 void layoutFragment(MCFragment *Fragment);
74 /// @name Section Access (in layout order)
77 llvm::SmallVectorImpl<MCSectionData*> &getSectionOrder() {
80 const llvm::SmallVectorImpl<MCSectionData*> &getSectionOrder() const {
85 /// @name Fragment Layout Data
88 /// \brief Get the offset of the given fragment inside its containing section.
89 uint64_t getFragmentOffset(const MCFragment *F) const;
92 /// @name Utility Functions
95 /// \brief Get the address space size of the given section, as it effects
96 /// layout. This may differ from the size reported by \see getSectionSize() by
97 /// not including section tail padding.
98 uint64_t getSectionAddressSize(const MCSectionData *SD) const;
100 /// \brief Get the data size of the given section, as emitted to the object
101 /// file. This may include additional padding, or be 0 for virtual sections.
102 uint64_t getSectionFileSize(const MCSectionData *SD) const;
104 /// \brief Get the offset of the given symbol, as computed in the current
106 /// \result True on success.
107 bool getSymbolOffset(const MCSymbolData *SD, uint64_t &Val) const;
109 /// \brief Variant that reports a fatal error if the offset is not computable.
110 uint64_t getSymbolOffset(const MCSymbolData *SD) const;
112 /// \brief If this symbol is equivalent to A + Constant, return A.
113 const MCSymbol *getBaseSymbol(const MCSymbol &Symbol) const;
118 } // end namespace llvm