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| 14 | pmbaty | 1 | //===- MCAsmLayout.h - Assembly Layout Object -------------------*- C++ -*-===// |
| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |||
| 9 | #ifndef LLVM_MC_MCASMLAYOUT_H |
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| 10 | #define LLVM_MC_MCASMLAYOUT_H |
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| 11 | |||
| 12 | #include "llvm/ADT/DenseMap.h" |
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| 13 | #include "llvm/ADT/SmallVector.h" |
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| 14 | |||
| 15 | namespace llvm { |
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| 16 | class MCAssembler; |
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| 17 | class MCFragment; |
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| 18 | class MCSection; |
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| 19 | class MCSymbol; |
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| 20 | |||
| 21 | /// Encapsulates the layout of an assembly file at a particular point in time. |
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| 22 | /// |
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| 23 | /// Assembly may require computing multiple layouts for a particular assembly |
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| 24 | /// file as part of the relaxation process. This class encapsulates the layout |
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| 25 | /// at a single point in time in such a way that it is always possible to |
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| 26 | /// efficiently compute the exact address of any symbol in the assembly file, |
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| 27 | /// even during the relaxation process. |
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| 28 | class MCAsmLayout { |
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| 29 | MCAssembler &Assembler; |
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| 30 | |||
| 31 | /// List of sections in layout order. |
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| 32 | llvm::SmallVector<MCSection *, 16> SectionOrder; |
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| 33 | |||
| 34 | /// The last fragment which was laid out, or 0 if nothing has been laid |
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| 35 | /// out. Fragments are always laid out in order, so all fragments with a |
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| 36 | /// lower ordinal will be valid. |
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| 37 | mutable DenseMap<const MCSection *, MCFragment *> LastValidFragment; |
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| 38 | |||
| 39 | /// Make sure that the layout for the given fragment is valid, lazily |
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| 40 | /// computing it if necessary. |
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| 41 | void ensureValid(const MCFragment *F) const; |
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| 42 | |||
| 43 | /// Is the layout for this fragment valid? |
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| 44 | bool isFragmentValid(const MCFragment *F) const; |
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| 45 | |||
| 46 | public: |
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| 47 | MCAsmLayout(MCAssembler &Assembler); |
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| 48 | |||
| 49 | /// Get the assembler object this is a layout for. |
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| 50 | MCAssembler &getAssembler() const { return Assembler; } |
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| 51 | |||
| 52 | /// \returns whether the offset of fragment \p F can be obtained via |
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| 53 | /// getFragmentOffset. |
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| 54 | bool canGetFragmentOffset(const MCFragment *F) const; |
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| 55 | |||
| 56 | /// Invalidate the fragments starting with F because it has been |
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| 57 | /// resized. The fragment's size should have already been updated, but |
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| 58 | /// its bundle padding will be recomputed. |
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| 59 | void invalidateFragmentsFrom(MCFragment *F); |
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| 60 | |||
| 61 | /// Perform layout for a single fragment, assuming that the previous |
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| 62 | /// fragment has already been laid out correctly, and the parent section has |
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| 63 | /// been initialized. |
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| 64 | void layoutFragment(MCFragment *Fragment); |
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| 65 | |||
| 66 | /// \name Section Access (in layout order) |
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| 67 | /// @{ |
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| 68 | |||
| 69 | llvm::SmallVectorImpl<MCSection *> &getSectionOrder() { return SectionOrder; } |
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| 70 | const llvm::SmallVectorImpl<MCSection *> &getSectionOrder() const { |
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| 71 | return SectionOrder; |
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| 72 | } |
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| 73 | |||
| 74 | /// @} |
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| 75 | /// \name Fragment Layout Data |
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| 76 | /// @{ |
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| 77 | |||
| 78 | /// Get the offset of the given fragment inside its containing section. |
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| 79 | uint64_t getFragmentOffset(const MCFragment *F) const; |
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| 80 | |||
| 81 | /// @} |
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| 82 | /// \name Utility Functions |
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| 83 | /// @{ |
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| 84 | |||
| 85 | /// Get the address space size of the given section, as it effects |
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| 86 | /// layout. This may differ from the size reported by \see |
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| 87 | /// getSectionFileSize() by not including section tail padding. |
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| 88 | uint64_t getSectionAddressSize(const MCSection *Sec) const; |
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| 89 | |||
| 90 | /// Get the data size of the given section, as emitted to the object |
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| 91 | /// file. This may include additional padding, or be 0 for virtual sections. |
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| 92 | uint64_t getSectionFileSize(const MCSection *Sec) const; |
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| 93 | |||
| 94 | /// Get the offset of the given symbol, as computed in the current |
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| 95 | /// layout. |
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| 96 | /// \return True on success. |
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| 97 | bool getSymbolOffset(const MCSymbol &S, uint64_t &Val) const; |
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| 98 | |||
| 99 | /// Variant that reports a fatal error if the offset is not computable. |
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| 100 | uint64_t getSymbolOffset(const MCSymbol &S) const; |
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| 101 | |||
| 102 | /// If this symbol is equivalent to A + Constant, return A. |
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| 103 | const MCSymbol *getBaseSymbol(const MCSymbol &Symbol) const; |
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| 104 | |||
| 105 | /// @} |
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| 106 | }; |
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| 107 | |||
| 108 | } // end namespace llvm |
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| 109 | |||
| 110 | #endif |