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//===- OutputSections.h -----------------------------------------*- C++ -*-===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLD_WASM_OUTPUT_SECTIONS_H
#define LLD_WASM_OUTPUT_SECTIONS_H
#include "InputChunks.h"
#include "WriterUtils.h"
#include "lld/Common/ErrorHandler.h"
#include "llvm/ADT/DenseMap.h"
using llvm::raw_ostream;
using llvm::raw_string_ostream;
namespace lld {
namespace wasm {
class OutputSection;
}
std::string toString(const wasm::OutputSection &Section);
namespace wasm {
class OutputSegment;
class OutputSection {
public:
OutputSection(uint32_t Type, std::string Name = "")
: Type(Type), Name(Name) {}
virtual ~OutputSection() = default;
StringRef getSectionName() const;
void setOffset(size_t NewOffset) {
log("setOffset: " + toString(*this) + ": " + Twine(NewOffset));
Offset = NewOffset;
}
void createHeader(size_t BodySize);
virtual size_t getSize() const = 0;
virtual void writeTo(uint8_t *Buf) = 0;
virtual void finalizeContents() {}
virtual uint32_t numRelocations() const { return 0; }
virtual void writeRelocations(raw_ostream &OS) const {}
std::string Header;
uint32_t Type;
std::string Name;
protected:
size_t Offset = 0;
};
class SyntheticSection : public OutputSection {
public:
SyntheticSection(uint32_t Type, std::string Name = "")
: OutputSection(Type, Name), BodyOutputStream(Body) {
if (!Name.empty())
writeStr(BodyOutputStream, Name, "section name");
}
void writeTo(uint8_t *Buf) override {
assert(Offset);
log("writing " + toString(*this));
memcpy(Buf + Offset, Header.data(), Header.size());
memcpy(Buf + Offset + Header.size(), Body.data(), Body.size());
}
size_t getSize() const override { return Header.size() + Body.size(); }
void finalizeContents() override {
BodyOutputStream.flush();
createHeader(Body.size());
}
raw_ostream &getStream() { return BodyOutputStream; }
std::string Body;
protected:
raw_string_ostream BodyOutputStream;
};
class CodeSection : public OutputSection {
public:
explicit CodeSection(ArrayRef<InputFunction *> Functions);
size_t getSize() const override { return Header.size() + BodySize; }
void writeTo(uint8_t *Buf) override;
uint32_t numRelocations() const override;
void writeRelocations(raw_ostream &OS) const override;
protected:
ArrayRef<InputFunction *> Functions;
std::string CodeSectionHeader;
size_t BodySize = 0;
};
class DataSection : public OutputSection {
public:
explicit DataSection(ArrayRef<OutputSegment *> Segments);
size_t getSize() const override { return Header.size() + BodySize; }
void writeTo(uint8_t *Buf) override;
uint32_t numRelocations() const override;
void writeRelocations(raw_ostream &OS) const override;
protected:
ArrayRef<OutputSegment *> Segments;
std::string DataSectionHeader;
size_t BodySize = 0;
};
// Represents a custom section in the output file. Wasm custom sections are
// used for storing user-defined metadata. Unlike the core sections types
// they are identified by their string name.
// The linker combines custom sections that have the same name by simply
// concatenating them.
// Note that some custom sections such as "name" and "linking" are handled
// separately and are instead synthesized by the linker.
class CustomSection : public OutputSection {
public:
CustomSection(std::string Name, ArrayRef<InputSection *> InputSections);
size_t getSize() const override {
return Header.size() + NameData.size() + PayloadSize;
}
void writeTo(uint8_t *Buf) override;
uint32_t numRelocations() const override;
void writeRelocations(raw_ostream &OS) const override;
protected:
size_t PayloadSize;
ArrayRef<InputSection *> InputSections;
std::string NameData;
};
} // namespace wasm
} // namespace lld
#endif // LLD_WASM_OUTPUT_SECTIONS_H
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