Write out global initializers and data rel directly to ELF file.

src/IceELFSection.h

Index: src/IceELFSection.h
diff --git a/src/IceELFSection.h b/src/IceELFSection.h
index 5821a8382d6caefa7855f5f8d5ef053fe43421fc..f2e384dffec0de1bc40eed62576b6dcdc8e556be 100644
--- a/src/IceELFSection.h
+++ b/src/IceELFSection.h
@@ -64,6 +64,10 @@ public:
   void setSize(Elf64_Xword sh_size) { Header.sh_size = sh_size; }
   SizeT getCurrentSize() const { return Header.sh_size; }
 
+  void setAlignment(Elf64_Xword sh_addralign) {
+    Header.sh_addralign = sh_addralign;
+  }
+
   void setNameStrIndex(Elf64_Word sh_name) { Header.sh_name = sh_name; }
 
   IceString getName() const { return Name; }
@@ -79,6 +83,8 @@ public:
   // Write the section header out with the given streamer.
   template <bool IsELF64> void writeHeader(ELFStreamer &Str);
 
+  void padToAlignment(ELFStreamer &Str, bool WritePadding, Elf64_Xword Align);
+
 protected:
   ~ELFSection() {}
 
@@ -117,6 +123,11 @@ public:
   using ELFSection::ELFSection;
 
   void appendData(ELFStreamer &Str, const llvm::StringRef MoreData);
+
+  void appendZeros(ELFStreamer &Str, SizeT NumBytes);
+
+  void appendRelocationOffset(ELFStreamer &Str, bool IsRela,
+                              RelocOffsetT RelocOffset);
 };
 
 // Model of ELF symbol table entries. Besides keeping track of the fields
@@ -195,13 +206,18 @@ class ELFRelocationSection : public ELFSection {
 public:
   using ELFSection::ELFSection;
 
-  ELFSection *getRelatedSection() const { return RelatedSection; }
-  void setRelatedSection(ELFSection *Section) { RelatedSection = Section; }
+  const ELFSection *getRelatedSection() const { return RelatedSection; }
+  void setRelatedSection(const ELFSection *Section) {
+    RelatedSection = Section;
+  }
 
   // Track additional relocations which start out relative to offset 0,
   // but should be adjusted to be relative to BaseOff.
   void addRelocations(RelocOffsetT BaseOff, const FixupRefList &FixupRefs);
 
+  // Track a single additional relocation.
+  void addRelocation(const AssemblerFixup &Fixup) { Fixups.push_back(Fixup); }
+
   size_t getSectionDataSize(const GlobalContext &Ctx,
                             const ELFSymbolTableSection *SymTab) const;
 
@@ -209,8 +225,10 @@ public:
   void writeData(const GlobalContext &Ctx, ELFStreamer &Str,
                  const ELFSymbolTableSection *SymTab);
 
+  bool isRela() const { return Header.sh_type == SHT_RELA; }
+
 private:
-  ELFSection *RelatedSection;
+  const ELFSection *RelatedSection;
   FixupList Fixups;
 };