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      1 //===- MCSectionWasm.h - Wasm Machine Code Sections -------------*- 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 // This file declares the MCSectionWasm class.
     10 //
     11 //===----------------------------------------------------------------------===//
     12 
     13 #ifndef LLVM_MC_MCSECTIONWASM_H
     14 #define LLVM_MC_MCSECTIONWASM_H
     15 
     16 #include "llvm/MC/MCSection.h"
     17 
     18 namespace llvm {
     19 
     20 class MCSymbol;
     21 class MCSymbolWasm;
     22 class StringRef;
     23 class raw_ostream;
     24 
     25 /// This represents a section on wasm.
     26 class MCSectionWasm final : public MCSection {
     27   unsigned UniqueID;
     28 
     29   const MCSymbolWasm *Group;
     30 
     31   // The offset of the MC function/data section in the wasm code/data section.
     32   // For data relocations the offset is relative to start of the data payload
     33   // itself and does not include the size of the section header.
     34   uint64_t SectionOffset = 0;
     35 
     36   // For data sections, this is the index of of the corresponding wasm data
     37   // segment
     38   uint32_t SegmentIndex = 0;
     39 
     40   // For data sections, whether to use a passive segment
     41   bool IsPassive = false;
     42 
     43   // For data sections, bitfield of WasmSegmentFlag
     44   unsigned SegmentFlags;
     45 
     46   // The storage of Name is owned by MCContext's WasmUniquingMap.
     47   friend class MCContext;
     48   MCSectionWasm(StringRef Name, SectionKind K, unsigned SegmentFlags,
     49                 const MCSymbolWasm *Group, unsigned UniqueID, MCSymbol *Begin)
     50       : MCSection(SV_Wasm, Name, K, Begin), UniqueID(UniqueID), Group(Group),
     51         SegmentFlags(SegmentFlags) {}
     52 
     53 public:
     54   /// Decides whether a '.section' directive should be printed before the
     55   /// section name
     56   bool shouldOmitSectionDirective(StringRef Name, const MCAsmInfo &MAI) const;
     57 
     58   const MCSymbolWasm *getGroup() const { return Group; }
     59   unsigned getSegmentFlags() const { return SegmentFlags; }
     60 
     61   void PrintSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
     62                             raw_ostream &OS,
     63                             const MCExpr *Subsection) const override;
     64   bool UseCodeAlign() const override;
     65   bool isVirtualSection() const override;
     66 
     67   bool isWasmData() const {
     68     return Kind.isGlobalWriteableData() || Kind.isReadOnly() ||
     69            Kind.isThreadLocal();
     70   }
     71 
     72   bool isUnique() const { return UniqueID != ~0U; }
     73   unsigned getUniqueID() const { return UniqueID; }
     74 
     75   uint64_t getSectionOffset() const { return SectionOffset; }
     76   void setSectionOffset(uint64_t Offset) { SectionOffset = Offset; }
     77 
     78   uint32_t getSegmentIndex() const { return SegmentIndex; }
     79   void setSegmentIndex(uint32_t Index) { SegmentIndex = Index; }
     80 
     81   bool getPassive() const {
     82     assert(isWasmData());
     83     return IsPassive;
     84   }
     85   void setPassive(bool V = true) {
     86     assert(isWasmData());
     87     IsPassive = V;
     88   }
     89   static bool classof(const MCSection *S) { return S->getVariant() == SV_Wasm; }
     90 };
     91 
     92 } // end namespace llvm
     93 
     94 #endif
     95