1 files changed, 138 insertions, 0 deletions
diff --git a/wasm/OutputSections.h b/wasm/OutputSections.h
new file mode 100644
index 000000000000..926101710cdf
--- /dev/null
+++ b/wasm/OutputSections.h
@@ -0,0 +1,138 @@
+//===- 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 "InputSegment.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(wasm::OutputSection *Section);
+
+namespace wasm {
+
+class OutputSegment;
+class ObjFile;
+
+class OutputSection {
+public:
+  OutputSection(uint32_t Type, std::string Name = "")
+      : Type(Type), Name(Name) {}
+
+  virtual ~OutputSection() = default;
+
+  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() {}
+
+  std::string Header;
+  uint32_t Type;
+  std::string Name;
+
+  virtual uint32_t numRelocations() const { return 0; }
+  virtual void writeRelocations(raw_ostream &OS) const {}
+
+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);
+  }
+
+  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;
+};
+
+// Some synthetic sections (e.g. "name" and "linking") have subsections.
+// Just like the synthetic sections themselves these need to be created before
+// they can be written out (since they are preceded by their length). This
+// class is used to create subsections and then write them into the stream
+// of the parent section.
+class SubSection : public SyntheticSection {
+public:
+  explicit SubSection(uint32_t Type) : SyntheticSection(Type) {}
+
+  void writeToStream(raw_ostream &OS) {
+    writeBytes(OS, Header.data(), Header.size());
+    writeBytes(OS, Body.data(), Body.size());
+  }
+};
+
+class CodeSection : public OutputSection {
+public:
+  explicit CodeSection(uint32_t NumFunctions, ArrayRef<ObjFile *> Objs);
+  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<ObjFile *> InputObjects;
+  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 { return Relocations.size(); }
+  void writeRelocations(raw_ostream &OS) const override;
+
+protected:
+  std::vector<OutputRelocation> Relocations;
+  ArrayRef<OutputSegment *> Segments;
+  std::string DataSectionHeader;
+  size_t BodySize = 0;
+};
+
+} // namespace wasm
+} // namespace lld
+
+#endif // LLD_WASM_OUTPUT_SECTIONS_H