llvm/tools/dsymutil/DwarfLinkerForBinary.h - llvm-project - Git at Google

 //===- tools/dsymutil/DwarfLinkerForBinary.h --------------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//

 #ifndef LLVM_TOOLS_DSYMUTIL_DWARFLINKER_H
 #define LLVM_TOOLS_DSYMUTIL_DWARFLINKER_H

 #include "BinaryHolder.h"
 #include "DebugMap.h"
 #include "LinkUtils.h"
 #include "llvm/DWARFLinker/DWARFLinker.h"
 #include "llvm/DWARFLinker/DWARFLinkerCompileUnit.h"
 #include "llvm/DWARFLinker/DWARFLinkerDeclContext.h"
 #include "llvm/DWARFLinker/DWARFStreamer.h"
 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
 #include "llvm/Remarks/RemarkFormat.h"
 #include "llvm/Remarks/RemarkLinker.h"

 namespace llvm {
 namespace dsymutil {

 /// The core of the Dsymutil Dwarf linking logic.
 ///
 /// The link of the dwarf information from the object files will be
 /// driven by DWARFLinker. DwarfLinkerForBinary reads DebugMap objects
 /// and pass information to the DWARFLinker. DWARFLinker
 /// optimizes DWARF taking into account valid relocations.
 /// Finally, optimized DWARF is passed to DwarfLinkerForBinary through
 /// DWARFEmitter interface.
 class DwarfLinkerForBinary {
 public:
   DwarfLinkerForBinary(raw_fd_ostream &OutFile, BinaryHolder &BinHolder,
                        LinkOptions Options)
       : OutFile(OutFile), BinHolder(BinHolder), Options(std::move(Options)) {}

   /// Link the contents of the DebugMap.
   bool link(const DebugMap &);

   void reportWarning(const Twine &Warning, StringRef Context,
                      const DWARFDie *DIE = nullptr) const;

   /// Flags passed to DwarfLinker::lookForDIEsToKeep
   enum TraversalFlags {
     TF_Keep = 1 << 0,            ///< Mark the traversed DIEs as kept.
     TF_InFunctionScope = 1 << 1, ///< Current scope is a function scope.
     TF_DependencyWalk = 1 << 2,  ///< Walking the dependencies of a kept DIE.
     TF_ParentWalk = 1 << 3,      ///< Walking up the parents of a kept DIE.
     TF_ODR = 1 << 4,             ///< Use the ODR while keeping dependents.
     TF_SkipPC = 1 << 5,          ///< Skip all location attributes.
   };

 private:

   /// Keeps track of relocations.
   class AddressManager : public AddressesMap {
     struct ValidReloc {
       uint64_t Offset;
       uint32_t Size;
       uint64_t Addend;
       const DebugMapObject::DebugMapEntry *Mapping;

       ValidReloc(uint64_t Offset, uint32_t Size, uint64_t Addend,
                  const DebugMapObject::DebugMapEntry *Mapping)
           : Offset(Offset), Size(Size), Addend(Addend), Mapping(Mapping) {}

       bool operator<(const ValidReloc &RHS) const {
         return Offset < RHS.Offset;
       }
       bool operator<(uint64_t RHS) const { return Offset < RHS; }
     };

     const DwarfLinkerForBinary &Linker;

     /// The valid relocations for the current DebugMapObject.
     /// This vector is sorted by relocation offset.
     /// {
     std::vector<ValidReloc> ValidDebugInfoRelocs;
     std::vector<ValidReloc> ValidDebugAddrRelocs;
     /// }

     RangesTy AddressRanges;

     StringRef SrcFileName;

     /// Returns list of valid relocations from \p Relocs,
     /// between \p StartOffset and \p NextOffset.
     ///
     /// \returns true if any relocation is found.
     std::vector<ValidReloc>
     getRelocations(const std::vector<ValidReloc> &Relocs, uint64_t StartPos,
                    uint64_t EndPos);

     /// Resolve specified relocation \p Reloc.
     ///
     /// \returns resolved value.
     uint64_t relocate(const ValidReloc &Reloc) const;

     /// Fill \p Info with address information for the specified \p Reloc.
     void fillDieInfo(const ValidReloc &Reloc, CompileUnit::DIEInfo &Info);

     /// Print contents of debug map entry for the specified \p Reloc.
     void printReloc(const ValidReloc &Reloc);

   public:
     AddressManager(DwarfLinkerForBinary &Linker, const object::ObjectFile &Obj,
                    const DebugMapObject &DMO)
         : Linker(Linker), SrcFileName(DMO.getObjectFilename()) {
       findValidRelocsInDebugSections(Obj, DMO);

       // Iterate over the debug map entries and put all the ones that are
       // functions (because they have a size) into the Ranges map. This map is
       // very similar to the FunctionRanges that are stored in each unit, with 2
       // notable differences:
       //
       //  1. Obviously this one is global, while the other ones are per-unit.
       //
       //  2. This one contains not only the functions described in the DIE
       //     tree, but also the ones that are only in the debug map.
       //
       // The latter information is required to reproduce dsymutil's logic while
       // linking line tables. The cases where this information matters look like
       // bugs that need to be investigated, but for now we need to reproduce
       // dsymutil's behavior.
       // FIXME: Once we understood exactly if that information is needed,
       // maybe totally remove this (or try to use it to do a real
       // -gline-tables-only on Darwin.
       for (const auto &Entry : DMO.symbols()) {
         const auto &Mapping = Entry.getValue();
         if (Mapping.Size && Mapping.ObjectAddress)
           AddressRanges[*Mapping.ObjectAddress] = ObjFileAddressRange(
               *Mapping.ObjectAddress + Mapping.Size,
               int64_t(Mapping.BinaryAddress) - *Mapping.ObjectAddress);
       }
     }
     virtual ~AddressManager() override { clear(); }

     virtual bool areRelocationsResolved() const override { return true; }

     bool hasValidRelocs() override {
       return !ValidDebugInfoRelocs.empty() || !ValidDebugAddrRelocs.empty();
     }

     /// \defgroup FindValidRelocations Translate debug map into a list
     /// of relevant relocations
     ///
     /// @{
     bool findValidRelocsInDebugSections(const object::ObjectFile &Obj,
                                         const DebugMapObject &DMO);

     bool findValidRelocs(const object::SectionRef &Section,
                          const object::ObjectFile &Obj,
                          const DebugMapObject &DMO,
                          std::vector<ValidReloc> &ValidRelocs);

     void findValidRelocsMachO(const object::SectionRef &Section,
                               const object::MachOObjectFile &Obj,
                               const DebugMapObject &DMO,
                               std::vector<ValidReloc> &ValidRelocs);
     /// @}

     /// Checks that there is a relocation in the \p Relocs array against a
     /// debug map entry between \p StartOffset and \p NextOffset.
     ///
     /// \returns true and sets Info.InDebugMap if it is the case.
     bool hasValidRelocationAt(const std::vector<ValidReloc> &Relocs,
                               uint64_t StartOffset, uint64_t EndOffset,
                               CompileUnit::DIEInfo &Info);

     bool hasLiveMemoryLocation(const DWARFDie &DIE,
                                CompileUnit::DIEInfo &Info) override;
     bool hasLiveAddressRange(const DWARFDie &DIE,
                              CompileUnit::DIEInfo &Info) override;

     bool applyValidRelocs(MutableArrayRef<char> Data, uint64_t BaseOffset,
                           bool IsLittleEndian) override;

     llvm::Expected<uint64_t> relocateIndexedAddr(uint64_t StartOffset,
                                                  uint64_t EndOffset) override;

     RangesTy &getValidAddressRanges() override { return AddressRanges; }

     void clear() override {
       AddressRanges.clear();
       ValidDebugInfoRelocs.clear();
       ValidDebugAddrRelocs.clear();
     }
   };

 private:
   /// \defgroup Helpers Various helper methods.
   ///
   /// @{
   bool createStreamer(const Triple &TheTriple, raw_fd_ostream &OutFile);

   /// Attempt to load a debug object from disk.
   ErrorOr<const object::ObjectFile &> loadObject(const DebugMapObject &Obj,
                                                  const Triple &triple);
   ErrorOr<DWARFFile &> loadObject(const DebugMapObject &Obj,
                                   const DebugMap &DebugMap,
                                   remarks::RemarkLinker &RL);

   raw_fd_ostream &OutFile;
   BinaryHolder &BinHolder;
   LinkOptions Options;
   std::unique_ptr<DwarfStreamer> Streamer;
   std::vector<std::unique_ptr<DWARFFile>> ObjectsForLinking;
   std::vector<std::unique_ptr<DWARFContext>> ContextForLinking;
   std::vector<std::unique_ptr<AddressManager>> AddressMapForLinking;
   std::vector<std::string> EmptyWarnings;

   /// A list of all .swiftinterface files referenced by the debug
   /// info, mapping Module name to path on disk. The entries need to
   /// be uniqued and sorted and there are only few entries expected
   /// per compile unit, which is why this is a std::map.
   std::map<std::string, std::string> ParseableSwiftInterfaces;

   bool ModuleCacheHintDisplayed = false;
   bool ArchiveHintDisplayed = false;
 };

 } // end namespace dsymutil
 } // end namespace llvm

 #endif // LLVM_TOOLS_DSYMUTIL_DWARFLINKER_H
	//===- tools/dsymutil/DwarfLinkerForBinary.h --------------------- C++ --===//
	//
	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
	// See https://llvm.org/LICENSE.txt for license information.
	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
	//
	//===----------------------------------------------------------------------===//

	#ifndef LLVM_TOOLS_DSYMUTIL_DWARFLINKER_H
	#define LLVM_TOOLS_DSYMUTIL_DWARFLINKER_H

	#include "BinaryHolder.h"
	#include "DebugMap.h"
	#include "LinkUtils.h"
	#include "llvm/DWARFLinker/DWARFLinker.h"
	#include "llvm/DWARFLinker/DWARFLinkerCompileUnit.h"
	#include "llvm/DWARFLinker/DWARFLinkerDeclContext.h"
	#include "llvm/DWARFLinker/DWARFStreamer.h"
	#include "llvm/DebugInfo/DWARF/DWARFContext.h"
	#include "llvm/Remarks/RemarkFormat.h"
	#include "llvm/Remarks/RemarkLinker.h"

	namespace llvm {
	namespace dsymutil {

	/// The core of the Dsymutil Dwarf linking logic.
	///
	/// The link of the dwarf information from the object files will be
	/// driven by DWARFLinker. DwarfLinkerForBinary reads DebugMap objects
	/// and pass information to the DWARFLinker. DWARFLinker
	/// optimizes DWARF taking into account valid relocations.
	/// Finally, optimized DWARF is passed to DwarfLinkerForBinary through
	/// DWARFEmitter interface.
	class DwarfLinkerForBinary {
	public:
	DwarfLinkerForBinary(raw_fd_ostream &OutFile, BinaryHolder &BinHolder,
	LinkOptions Options)
	: OutFile(OutFile), BinHolder(BinHolder), Options(std::move(Options)) {}

	/// Link the contents of the DebugMap.
	bool link(const DebugMap &);

	void reportWarning(const Twine &Warning, StringRef Context,
	const DWARFDie *DIE = nullptr) const;

	/// Flags passed to DwarfLinker::lookForDIEsToKeep
	enum TraversalFlags {
	TF_Keep = 1 << 0, ///< Mark the traversed DIEs as kept.
	TF_InFunctionScope = 1 << 1, ///< Current scope is a function scope.
	TF_DependencyWalk = 1 << 2, ///< Walking the dependencies of a kept DIE.
	TF_ParentWalk = 1 << 3, ///< Walking up the parents of a kept DIE.
	TF_ODR = 1 << 4, ///< Use the ODR while keeping dependents.
	TF_SkipPC = 1 << 5, ///< Skip all location attributes.
	};

	private:

	/// Keeps track of relocations.
	class AddressManager : public AddressesMap {
	struct ValidReloc {
	uint64_t Offset;
	uint32_t Size;
	uint64_t Addend;
	const DebugMapObject::DebugMapEntry *Mapping;

	ValidReloc(uint64_t Offset, uint32_t Size, uint64_t Addend,
	const DebugMapObject::DebugMapEntry *Mapping)
	: Offset(Offset), Size(Size), Addend(Addend), Mapping(Mapping) {}

	bool operator<(const ValidReloc &RHS) const {
	return Offset < RHS.Offset;
	}
	bool operator<(uint64_t RHS) const { return Offset < RHS; }
	};

	const DwarfLinkerForBinary &Linker;

	/// The valid relocations for the current DebugMapObject.
	/// This vector is sorted by relocation offset.
	/// {
	std::vector<ValidReloc> ValidDebugInfoRelocs;
	std::vector<ValidReloc> ValidDebugAddrRelocs;
	/// }

	RangesTy AddressRanges;

	StringRef SrcFileName;

	/// Returns list of valid relocations from \p Relocs,
	/// between \p StartOffset and \p NextOffset.
	///
	/// \returns true if any relocation is found.
	std::vector<ValidReloc>
	getRelocations(const std::vector<ValidReloc> &Relocs, uint64_t StartPos,
	uint64_t EndPos);

	/// Resolve specified relocation \p Reloc.
	///
	/// \returns resolved value.
	uint64_t relocate(const ValidReloc &Reloc) const;

	/// Fill \p Info with address information for the specified \p Reloc.
	void fillDieInfo(const ValidReloc &Reloc, CompileUnit::DIEInfo &Info);

	/// Print contents of debug map entry for the specified \p Reloc.
	void printReloc(const ValidReloc &Reloc);

	public:
	AddressManager(DwarfLinkerForBinary &Linker, const object::ObjectFile &Obj,
	const DebugMapObject &DMO)
	: Linker(Linker), SrcFileName(DMO.getObjectFilename()) {
	findValidRelocsInDebugSections(Obj, DMO);

	// Iterate over the debug map entries and put all the ones that are
	// functions (because they have a size) into the Ranges map. This map is
	// very similar to the FunctionRanges that are stored in each unit, with 2
	// notable differences:
	//
	// 1. Obviously this one is global, while the other ones are per-unit.
	//
	// 2. This one contains not only the functions described in the DIE
	// tree, but also the ones that are only in the debug map.
	//
	// The latter information is required to reproduce dsymutil's logic while
	// linking line tables. The cases where this information matters look like
	// bugs that need to be investigated, but for now we need to reproduce
	// dsymutil's behavior.
	// FIXME: Once we understood exactly if that information is needed,
	// maybe totally remove this (or try to use it to do a real
	// -gline-tables-only on Darwin.
	for (const auto &Entry : DMO.symbols()) {
	const auto &Mapping = Entry.getValue();
	if (Mapping.Size && Mapping.ObjectAddress)
	AddressRanges[*Mapping.ObjectAddress] = ObjFileAddressRange(
	*Mapping.ObjectAddress + Mapping.Size,
	int64_t(Mapping.BinaryAddress) - *Mapping.ObjectAddress);
	}
	}
	virtual ~AddressManager() override { clear(); }

	virtual bool areRelocationsResolved() const override { return true; }

	bool hasValidRelocs() override {
	return !ValidDebugInfoRelocs.empty() \|\| !ValidDebugAddrRelocs.empty();
	}

	/// \defgroup FindValidRelocations Translate debug map into a list
	/// of relevant relocations
	///
	/// @{
	bool findValidRelocsInDebugSections(const object::ObjectFile &Obj,
	const DebugMapObject &DMO);

	bool findValidRelocs(const object::SectionRef &Section,
	const object::ObjectFile &Obj,
	const DebugMapObject &DMO,
	std::vector<ValidReloc> &ValidRelocs);

	void findValidRelocsMachO(const object::SectionRef &Section,
	const object::MachOObjectFile &Obj,
	const DebugMapObject &DMO,
	std::vector<ValidReloc> &ValidRelocs);
	/// @}

	/// Checks that there is a relocation in the \p Relocs array against a
	/// debug map entry between \p StartOffset and \p NextOffset.
	///
	/// \returns true and sets Info.InDebugMap if it is the case.
	bool hasValidRelocationAt(const std::vector<ValidReloc> &Relocs,
	uint64_t StartOffset, uint64_t EndOffset,
	CompileUnit::DIEInfo &Info);

	bool hasLiveMemoryLocation(const DWARFDie &DIE,
	CompileUnit::DIEInfo &Info) override;
	bool hasLiveAddressRange(const DWARFDie &DIE,
	CompileUnit::DIEInfo &Info) override;

	bool applyValidRelocs(MutableArrayRef<char> Data, uint64_t BaseOffset,
	bool IsLittleEndian) override;

	llvm::Expected<uint64_t> relocateIndexedAddr(uint64_t StartOffset,
	uint64_t EndOffset) override;

	RangesTy &getValidAddressRanges() override { return AddressRanges; }

	void clear() override {
	AddressRanges.clear();
	ValidDebugInfoRelocs.clear();
	ValidDebugAddrRelocs.clear();
	}
	};

	private:
	/// \defgroup Helpers Various helper methods.
	///
	/// @{
	bool createStreamer(const Triple &TheTriple, raw_fd_ostream &OutFile);

	/// Attempt to load a debug object from disk.
	ErrorOr<const object::ObjectFile &> loadObject(const DebugMapObject &Obj,
	const Triple &triple);
	ErrorOr<DWARFFile &> loadObject(const DebugMapObject &Obj,
	const DebugMap &DebugMap,
	remarks::RemarkLinker &RL);

	raw_fd_ostream &OutFile;
	BinaryHolder &BinHolder;
	LinkOptions Options;
	std::unique_ptr<DwarfStreamer> Streamer;
	std::vector<std::unique_ptr<DWARFFile>> ObjectsForLinking;
	std::vector<std::unique_ptr<DWARFContext>> ContextForLinking;
	std::vector<std::unique_ptr<AddressManager>> AddressMapForLinking;
	std::vector<std::string> EmptyWarnings;

	/// A list of all .swiftinterface files referenced by the debug
	/// info, mapping Module name to path on disk. The entries need to
	/// be uniqued and sorted and there are only few entries expected
	/// per compile unit, which is why this is a std::map.
	std::map<std::string, std::string> ParseableSwiftInterfaces;

	bool ModuleCacheHintDisplayed = false;
	bool ArchiveHintDisplayed = false;
	};

	} // end namespace dsymutil
	} // end namespace llvm

	#endif // LLVM_TOOLS_DSYMUTIL_DWARFLINKER_H