a96f3a3da4
Changes :- a) Functionality in InputGraph to insert Input elements at any position b) Functionality in the Resolver to use nextFile c) Move the functionality of assigning file ordinals to InputGraph d) Changes all inputs to MemoryBuffers e) Remove LinkerInput, InputFiles, ReaderArchive llvm-svn: 192081
119 lines
3.7 KiB
C++
119 lines
3.7 KiB
C++
//===- lib/ReaderWriter/PECOFF/LinkerGeneratedSymbolFile.cpp --------------===//
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//
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// The LLVM Linker
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "Atoms.h"
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#include "GroupedSectionsPass.h"
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#include "IdataPass.h"
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#include "llvm/ADT/SmallString.h"
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#include "llvm/Support/Allocator.h"
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#include "llvm/Support/Path.h"
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#include "lld/Core/ArchiveLibraryFile.h"
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#include "lld/Core/PassManager.h"
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#include "lld/Passes/LayoutPass.h"
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#include "lld/ReaderWriter/PECOFFLinkingContext.h"
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#include "lld/ReaderWriter/Reader.h"
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#include "lld/ReaderWriter/Simple.h"
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#include "lld/ReaderWriter/Writer.h"
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namespace lld {
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namespace coff {
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namespace {
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// The symbol __ImageBase is a linker generated symbol. No standard library
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// files define it, but the linker is expected to prepare it as if it was read
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// from a file. The content of the atom is a 4-byte integer equal to the image
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// base address. Note that because the name is prefixed by an underscore on x86
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// Win32, the actual symbol name will be ___ImageBase (three underscores).
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class ImageBaseAtom : public COFFLinkerInternalAtom {
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public:
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ImageBaseAtom(const PECOFFLinkingContext &context, const File &file,
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uint32_t imageBase)
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: COFFLinkerInternalAtom(file, assembleRawContent(imageBase)),
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_name(context.decorateSymbol("__ImageBase")) {}
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virtual StringRef name() const { return _name; }
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virtual uint64_t ordinal() const { return 0; }
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virtual ContentType contentType() const { return typeData; }
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virtual ContentPermissions permissions() const { return permRW_; }
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virtual DeadStripKind deadStrip() const { return deadStripAlways; }
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private:
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std::vector<uint8_t> assembleRawContent(uint32_t imageBase) {
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std::vector<uint8_t> data = std::vector<uint8_t>(4);
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*(reinterpret_cast<uint32_t *>(&data[0])) = imageBase;
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return data;
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}
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StringRef _name;
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};
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// The file to wrap ImageBaseAtom. This is the only member file of
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// LinkerGeneratedSymbolFile.
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class MemberFile : public SimpleFile {
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public:
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MemberFile(const PECOFFLinkingContext &context)
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: SimpleFile(context, "Member of the Linker Internal File"),
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_atom(context, *this, context.getBaseAddress()) {
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addAtom(_atom);
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};
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bool contains(StringRef name) const {
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return _atom.name() == name;
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}
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private:
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ImageBaseAtom _atom;
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};
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} // anonymous namespace
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// A pseudo library file to wrap MemberFile, which in turn wraps ImageBaseAtom.
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// The file the core linker handle is this.
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//
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// The reason why we don't pass MemberFile to the core linker is because, if we
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// did so, ImageBaseAtom would always be emit to the resultant executable. By
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// wrapping the file by a library file, we made it to emit ImageBaseAtom only
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// when the atom is really referenced.
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class LinkerGeneratedSymbolFile : public ArchiveLibraryFile {
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public:
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LinkerGeneratedSymbolFile(const PECOFFLinkingContext &context)
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: ArchiveLibraryFile(context, "Linker Internal File"),
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_memberFile(context) {};
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virtual const File *find(StringRef name, bool dataSymbolOnly) const {
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if (_memberFile.contains(name))
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return &_memberFile;
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return nullptr;
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}
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virtual const atom_collection<DefinedAtom> &defined() const {
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return _noDefinedAtoms;
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}
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virtual const atom_collection<UndefinedAtom> &undefined() const {
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return _noUndefinedAtoms;
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}
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virtual const atom_collection<SharedLibraryAtom> &sharedLibrary() const {
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return _noSharedLibraryAtoms;
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}
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virtual const atom_collection<AbsoluteAtom> &absolute() const {
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return _noAbsoluteAtoms;
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}
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private:
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MemberFile _memberFile;
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};
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} // end namespace coff
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} // end namespace lld
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