Add hybrid assembler concept to ARM assembler.

src/IceAssembler.cpp

Index: src/IceAssembler.cpp
diff --git a/src/IceAssembler.cpp b/src/IceAssembler.cpp
index 7eb8b61aa13258aa770d1517f30b37a812cbdfee..6072bbf021cf8a1d1de48384f264aa0b3d4ad95a 100644
--- a/src/IceAssembler.cpp
+++ b/src/IceAssembler.cpp
@@ -35,15 +35,19 @@ static uintptr_t NewContents(Assembler &Assemblr, intptr_t Capacity) {
   return Result;
 }
 
+void AssemblerBuffer::installFixup(AssemblerFixup *F) {
+  F->set_position(0);
+  if (!Assemblr.getPreliminary())
+    Fixups.push_back(F);
+}
+
 AssemblerFixup *AssemblerBuffer::createFixup(FixupKind Kind,
                                              const Constant *Value) {
   AssemblerFixup *F =
       new (Assemblr.allocate<AssemblerFixup>()) AssemblerFixup();
-  F->set_position(0);
   F->set_kind(Kind);
   F->set_value(Value);
-  if (!Assemblr.getPreliminary())
-    Fixups.push_back(F);
+  installFixup(F);
   return F;
 }
 
@@ -123,7 +127,6 @@ void Assembler::emitIASBytes() const {
   Ostream &Str = Ctx->getStrEmit();
   intptr_t EndPosition = Buffer.size();
   intptr_t CurPosition = 0;
-  const intptr_t FixupSize = 4;
   for (const AssemblerFixup *NextFixup : fixups()) {
     intptr_t NextFixupLoc = NextFixup->position();
     for (intptr_t i = CurPosition; i < NextFixupLoc; ++i) {
@@ -131,16 +134,13 @@ void Assembler::emitIASBytes() const {
       Str.write_hex(Buffer.load<uint8_t>(i));
       Str << "\n";
     }
-    Str << "\t.long ";
     // For PCRel fixups, we write the pc-offset from a symbol into the Buffer
     // (e.g., -4), but we don't represent that in the fixup's offset. Otherwise
     // the fixup holds the true offset, and so does the Buffer. Just load the
     // offset from the buffer.
-    NextFixup->emit(Ctx, Buffer.load<RelocOffsetT>(NextFixupLoc));
-    if (fixupIsPCRel(NextFixup->kind()))
-      Str << " - .";
-    Str << "\n";
-    CurPosition = NextFixupLoc + FixupSize;
+    CurPosition = NextFixupLoc +
+                  NextFixup->emit(Ctx, Buffer.load<RelocOffsetT>(NextFixupLoc),
+                                  fixupIsPCRel(NextFixup->kind()));
     assert(CurPosition <= EndPosition);
   }
   // Handle any bytes that are not prefixed by a fixup.