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

src/IceELFSection.cpp

Index: src/IceELFSection.cpp
diff --git a/src/IceELFSection.cpp b/src/IceELFSection.cpp
index 5dcc206df8d61849ba2cd529ceed6967fa366a23..e56137f5548b8deb198c40865e284fcce4b44ee9 100644
--- a/src/IceELFSection.cpp
+++ b/src/IceELFSection.cpp
@@ -11,6 +11,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/Support/MathExtras.h"
+
 #include "IceDefs.h"
 #include "IceELFSection.h"
 #include "IceELFStreamer.h"
@@ -35,6 +37,34 @@ void ELFDataSection::appendData(ELFStreamer &Str,
   Header.sh_size += MoreData.size();
 }
 
+void ELFDataSection::appendZeros(ELFStreamer &Str, SizeT NumBytes) {
+  Str.writeZeroPadding(NumBytes);
+  Header.sh_size += NumBytes;
+}
+
+void ELFDataSection::appendRelocationOffset(ELFStreamer &Str, bool IsRela,
+                                            RelocOffsetT RelocOffset) {
+  if (IsRela) {
+    appendZeros(Str, RelocAddrSize);
+    return;
+  }
+  static_assert(RelocAddrSize == 4, " writeLE32 assumes RelocAddrSize is 4");
+  Str.writeLE32(RelocOffset);
+  Header.sh_size += RelocAddrSize;
+}
+
+void ELFDataSection::padToAlignment(ELFStreamer &Str, Elf64_Xword Align) {
+  assert(llvm::isPowerOf2_32(Align));
+  Elf64_Xword Mod = Header.sh_size & (Align - 1);
+  if (Mod == 0)
+    return;
+  Elf64_Xword AlignDiff = Align - Mod;

[Jim Stichnoth, 2015/01/27 16:44:55]

I've seen this pattern (which I think takes a bit of head-scratching to convince
oneself of its correctness) in a few other places, e.g.
ELFObjectWriter::alignFileOffset() and AssemblerX86::alignFunction(), maybe
more.  Would it be practical to refactor it?

[jvoung (off chromium), 2015/01/28 17:46:22]

How about having something like OffsetToAlignment() (or whatever name) for
calculating the diff, and then the padding adjustment just uses that diff (but
is different for each function)? That'll hide the math at least.

+  if (Header.sh_type != llvm::ELF::SHT_NOBITS)
+    Str.writeZeroPadding(AlignDiff);
+  Header.sh_size += AlignDiff;
+  assert((Header.sh_size & (Align - 1)) == 0);
+}
+
 // Relocation sections.
 
 void ELFRelocationSection::addRelocations(RelocOffsetT BaseOff,
@@ -73,7 +103,7 @@ void ELFSymbolTableSection::createDefinedSym(const IceString &Name,
   NewSymbol.Section = Section;
   NewSymbol.Number = ELFSym::UnknownNumber;
   bool Unique;
-  if (Type == STB_LOCAL)
+  if (Binding == STB_LOCAL)
     Unique = LocalSymbols.insert(std::make_pair(Name, NewSymbol)).second;
   else
     Unique = GlobalSymbols.insert(std::make_pair(Name, NewSymbol)).second;