Subzero: Add basic ELFObjectWriter (text section, symtab, strtab, headers)

src/IceCfg.cpp

 //===- subzero/src/IceCfg.cpp - Control flow graph implementation ---------===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the Cfg class, including constant pool
@@ skipping 387 matching lines @@
 void Cfg::emitTextHeader(const IceString &MangledName) {
   // Note: Still used by emit IAS.
   Ostream &Str = Ctx->getStrEmit();
   Str << "\t.text\n";
   if (Ctx->getFlags().FunctionSections)
     Str << "\t.section\t.text." << MangledName << ",\"ax\",@progbits\n";
   if (!getInternal() || Ctx->getFlags().DisableInternal) {
     Str << "\t.globl\t" << MangledName << "\n";
     Str << "\t.type\t" << MangledName << ",@function\n";
   }
-  Str << "\t.p2align " << getTarget()->getBundleAlignLog2Bytes() << ",0x";
-  for (AsmCodeByte I : getTarget()->getNonExecBundlePadding())
+  Assembler *Asm = getAssembler<Assembler>();
+  Str << "\t.p2align " << Asm->getBundleAlignLog2Bytes() << ",0x";
+  for (uint8_t I : Asm->getNonExecBundlePadding())
     Str.write_hex(I);
   Str << "\n";
   Str << MangledName << ":\n";
 }
 
 void Cfg::emit() {
   if (!ALLOW_DUMP)
     return;
   TimerMarker T(TimerStack::TT_emit, this);
   if (Ctx->getFlags().DecorateAsm) {
@@ skipping 17 matching lines @@
   emitTextHeader(MangledName);
   for (CfgNode *Node : Nodes)
     Node->emit(this);
   Str << "\n";
 }
 
 void Cfg::emitIAS() {
   TimerMarker T(TimerStack::TT_emit, this);
   assert(!Ctx->getFlags().DecorateAsm);
   IceString MangledName = getContext()->mangleName(getFunctionName());
-  emitTextHeader(MangledName);
+  if (!Ctx->getFlags().UseELFWriter)
+    emitTextHeader(MangledName);
   for (CfgNode *Node : Nodes)
     Node->emitIAS(this);
-  getAssembler<Assembler>()->emitIASBytes(Ctx);
+  // Now write the function to the file and track.
+  if (Ctx->getFlags().UseELFWriter) {
+    getAssembler<Assembler>()->alignFunction();
+    // TODO(jvoung): Transfer remaining fixups too. They may need their
+    // offsets adjusted.
+    Ctx->getObjectWriter()->writeFunctionCode(
+        MangledName, getInternal(), getAssembler<Assembler>()->getBufferView());
+  } else {
+    getAssembler<Assembler>()->emitIASBytes(Ctx);
+  }
 }
 
 // Dumps the IR with an optional introductory message.
 void Cfg::dump(const IceString &Message) {
   if (!ALLOW_DUMP)
     return;
   if (!Ctx->isVerbose())
     return;
   Ostream &Str = Ctx->getStrDump();
   if (!Message.empty())
@@ skipping 28 matching lines @@
     }
   }
   // Print each basic block
   for (CfgNode *Node : Nodes)
     Node->dump(this);
   if (getContext()->isVerbose(IceV_Instructions))
     Str << "}\n";
 }
 
 } // end of namespace Ice