Yi Kong | 8328301 | 2023-12-13 12:57:00 +0900 | [diff] [blame^] | 1 | //===- MCAsmLayout.h - Assembly Layout Object -------------------*- C++ -*-===// |
| 2 | // |
| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | // See https://llvm.org/LICENSE.txt for license information. |
| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | // |
| 7 | //===----------------------------------------------------------------------===// |
| 8 | |
| 9 | #ifndef LLVM_MC_MCASMLAYOUT_H |
| 10 | #define LLVM_MC_MCASMLAYOUT_H |
| 11 | |
| 12 | #include "llvm/ADT/DenseMap.h" |
| 13 | #include "llvm/ADT/SmallVector.h" |
| 14 | |
| 15 | namespace llvm { |
| 16 | class MCAssembler; |
| 17 | class MCFragment; |
| 18 | class MCSection; |
| 19 | class MCSymbol; |
| 20 | |
| 21 | /// Encapsulates the layout of an assembly file at a particular point in time. |
| 22 | /// |
| 23 | /// Assembly may require computing multiple layouts for a particular assembly |
| 24 | /// file as part of the relaxation process. This class encapsulates the layout |
| 25 | /// at a single point in time in such a way that it is always possible to |
| 26 | /// efficiently compute the exact address of any symbol in the assembly file, |
| 27 | /// even during the relaxation process. |
| 28 | class MCAsmLayout { |
| 29 | MCAssembler &Assembler; |
| 30 | |
| 31 | /// List of sections in layout order. |
| 32 | llvm::SmallVector<MCSection *, 16> SectionOrder; |
| 33 | |
| 34 | /// The last fragment which was laid out, or 0 if nothing has been laid |
| 35 | /// out. Fragments are always laid out in order, so all fragments with a |
| 36 | /// lower ordinal will be valid. |
| 37 | mutable DenseMap<const MCSection *, MCFragment *> LastValidFragment; |
| 38 | |
| 39 | /// Make sure that the layout for the given fragment is valid, lazily |
| 40 | /// computing it if necessary. |
| 41 | void ensureValid(const MCFragment *F) const; |
| 42 | |
| 43 | /// Is the layout for this fragment valid? |
| 44 | bool isFragmentValid(const MCFragment *F) const; |
| 45 | |
| 46 | public: |
| 47 | MCAsmLayout(MCAssembler &Assembler); |
| 48 | |
| 49 | /// Get the assembler object this is a layout for. |
| 50 | MCAssembler &getAssembler() const { return Assembler; } |
| 51 | |
| 52 | /// \returns whether the offset of fragment \p F can be obtained via |
| 53 | /// getFragmentOffset. |
| 54 | bool canGetFragmentOffset(const MCFragment *F) const; |
| 55 | |
| 56 | /// Invalidate the fragments starting with F because it has been |
| 57 | /// resized. The fragment's size should have already been updated, but |
| 58 | /// its bundle padding will be recomputed. |
| 59 | void invalidateFragmentsFrom(MCFragment *F); |
| 60 | |
| 61 | /// Perform layout for a single fragment, assuming that the previous |
| 62 | /// fragment has already been laid out correctly, and the parent section has |
| 63 | /// been initialized. |
| 64 | void layoutFragment(MCFragment *Fragment); |
| 65 | |
| 66 | /// \name Section Access (in layout order) |
| 67 | /// @{ |
| 68 | |
| 69 | llvm::SmallVectorImpl<MCSection *> &getSectionOrder() { return SectionOrder; } |
| 70 | const llvm::SmallVectorImpl<MCSection *> &getSectionOrder() const { |
| 71 | return SectionOrder; |
| 72 | } |
| 73 | |
| 74 | /// @} |
| 75 | /// \name Fragment Layout Data |
| 76 | /// @{ |
| 77 | |
| 78 | /// Get the offset of the given fragment inside its containing section. |
| 79 | uint64_t getFragmentOffset(const MCFragment *F) const; |
| 80 | |
| 81 | /// @} |
| 82 | /// \name Utility Functions |
| 83 | /// @{ |
| 84 | |
| 85 | /// Get the address space size of the given section, as it effects |
| 86 | /// layout. This may differ from the size reported by \see |
| 87 | /// getSectionFileSize() by not including section tail padding. |
| 88 | uint64_t getSectionAddressSize(const MCSection *Sec) const; |
| 89 | |
| 90 | /// Get the data size of the given section, as emitted to the object |
| 91 | /// file. This may include additional padding, or be 0 for virtual sections. |
| 92 | uint64_t getSectionFileSize(const MCSection *Sec) const; |
| 93 | |
| 94 | /// Get the offset of the given symbol, as computed in the current |
| 95 | /// layout. |
| 96 | /// \return True on success. |
| 97 | bool getSymbolOffset(const MCSymbol &S, uint64_t &Val) const; |
| 98 | |
| 99 | /// Variant that reports a fatal error if the offset is not computable. |
| 100 | uint64_t getSymbolOffset(const MCSymbol &S) const; |
| 101 | |
| 102 | /// If this symbol is equivalent to A + Constant, return A. |
| 103 | const MCSymbol *getBaseSymbol(const MCSymbol &Symbol) const; |
| 104 | |
| 105 | /// @} |
| 106 | }; |
| 107 | |
| 108 | } // end namespace llvm |
| 109 | |
| 110 | #endif |