Refactor MCInstFragment and MCDataFragment to adhere to a common interface,
which removes code duplication and prepares the ground for future additions.

Full discussion:
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20121203/158233.html

llvm-svn: 169626
diff --git a/llvm/lib/MC/MCAssembler.cpp b/llvm/lib/MC/MCAssembler.cpp
index 5032e6f..b2136e5 100644
--- a/llvm/lib/MC/MCAssembler.cpp
+++ b/llvm/lib/MC/MCAssembler.cpp
@@ -168,6 +168,11 @@
 
 /* *** */
 
+MCEncodedFragment::~MCEncodedFragment() {
+}
+
+/* *** */
+
 MCSectionData::MCSectionData() : Section(0) {}
 
 MCSectionData::MCSectionData(const MCSection &_Section, MCAssembler *A)
@@ -382,9 +387,16 @@
   LastValidFragment[F->getParent()] = F;
 }
 
-/// WriteFragmentData - Write the \p F data to the output file.
-static void WriteFragmentData(const MCAssembler &Asm, const MCAsmLayout &Layout,
-                              const MCFragment &F) {
+/// \brief Write the contents of a fragment to the given object writer. Expects
+///        a MCEncodedFragment.
+static void writeFragmentContents(const MCFragment &F, MCObjectWriter *OW) {
+  MCEncodedFragment &EF = cast<MCEncodedFragment>(F);
+  OW->WriteBytes(EF.getContents().str());
+}
+
+/// \brief Write the fragment \p F to the output file.
+static void writeFragment(const MCAssembler &Asm, const MCAsmLayout &Layout,
+                          const MCFragment &F) {
   MCObjectWriter *OW = &Asm.getWriter();
   uint64_t Start = OW->getStream().tell();
   (void) Start;
@@ -433,13 +445,15 @@
     break;
   }
 
-  case MCFragment::FT_Data: {
+  case MCFragment::FT_Data: 
     ++stats::EmittedDataFragments;
-    MCDataFragment &DF = cast<MCDataFragment>(F);
-    assert(FragmentSize == DF.getContents().size() && "Invalid size!");
-    OW->WriteBytes(DF.getContents().str());
+    writeFragmentContents(F, OW);
     break;
-  }
+
+  case MCFragment::FT_Inst:
+    ++stats::EmittedInstFragments;
+    writeFragmentContents(F, OW);
+    break;
 
   case MCFragment::FT_Fill: {
     MCFillFragment &FF = cast<MCFillFragment>(F);
@@ -458,13 +472,6 @@
     break;
   }
 
-  case MCFragment::FT_Inst: {
-    ++stats::EmittedInstFragments;
-    MCInstFragment &IF = cast<MCInstFragment>(F);
-    OW->WriteBytes(StringRef(IF.getCode().begin(), IF.getCode().size()));
-    break;
-  }
-
   case MCFragment::FT_LEB: {
     MCLEBFragment &LF = cast<MCLEBFragment>(F);
     OW->WriteBytes(LF.getContents().str());
@@ -538,9 +545,9 @@
   uint64_t Start = getWriter().getStream().tell();
   (void)Start;
 
-  for (MCSectionData::const_iterator it = SD->begin(),
-         ie = SD->end(); it != ie; ++it)
-    WriteFragmentData(*this, Layout, *it);
+  for (MCSectionData::const_iterator it = SD->begin(), ie = SD->end();
+       it != ie; ++it)
+    writeFragment(*this, Layout, *it);
 
   assert(getWriter().getStream().tell() - Start ==
          Layout.getSectionAddressSize(SD));
@@ -617,24 +624,14 @@
   for (MCAssembler::iterator it = begin(), ie = end(); it != ie; ++it) {
     for (MCSectionData::iterator it2 = it->begin(),
            ie2 = it->end(); it2 != ie2; ++it2) {
-      MCDataFragment *DF = dyn_cast<MCDataFragment>(it2);
-      if (DF) {
-        for (MCDataFragment::fixup_iterator it3 = DF->fixup_begin(),
-               ie3 = DF->fixup_end(); it3 != ie3; ++it3) {
+      MCEncodedFragment *F = dyn_cast<MCEncodedFragment>(it2);
+      if (F) {
+        for (MCEncodedFragment::fixup_iterator it3 = F->fixup_begin(),
+             ie3 = F->fixup_end(); it3 != ie3; ++it3) {
           MCFixup &Fixup = *it3;
-          uint64_t FixedValue = handleFixup(Layout, *DF, Fixup);
-          getBackend().applyFixup(Fixup, DF->getContents().data(),
-                                  DF->getContents().size(), FixedValue);
-        }
-      }
-      MCInstFragment *IF = dyn_cast<MCInstFragment>(it2);
-      if (IF) {
-        for (MCInstFragment::fixup_iterator it3 = IF->fixup_begin(),
-               ie3 = IF->fixup_end(); it3 != ie3; ++it3) {
-          MCFixup &Fixup = *it3;
-          uint64_t FixedValue = handleFixup(Layout, *IF, Fixup);
-          getBackend().applyFixup(Fixup, IF->getCode().data(),
-                                  IF->getCode().size(), FixedValue);
+          uint64_t FixedValue = handleFixup(Layout, *F, Fixup);
+          getBackend().applyFixup(Fixup, F->getContents().data(),
+                                  F->getContents().size(), FixedValue);
         }
       }
     }
@@ -704,11 +701,8 @@
 
   // Update the instruction fragment.
   IF.setInst(Relaxed);
-  IF.getCode() = Code;
-  IF.getFixups().clear();
-  // FIXME: Eliminate copy.
-  for (unsigned i = 0, e = Fixups.size(); i != e; ++i)
-    IF.getFixups().push_back(Fixups[i]);
+  IF.getContents() = Code;
+  IF.getFixups() = Fixups;
 
   return true;
 }
@@ -977,6 +971,7 @@
 #endif
 
 // anchors for MC*Fragment vtables
+void MCEncodedFragment::anchor() { }
 void MCDataFragment::anchor() { }
 void MCInstFragment::anchor() { }
 void MCAlignFragment::anchor() { }
diff --git a/llvm/lib/MC/MCELFStreamer.cpp b/llvm/lib/MC/MCELFStreamer.cpp
index b1952bf..8b9bdb1 100644
--- a/llvm/lib/MC/MCELFStreamer.cpp
+++ b/llvm/lib/MC/MCELFStreamer.cpp
@@ -345,7 +345,7 @@
   // Add the fixups and data.
   for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
     Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
-    DF->addFixup(Fixups[i]);
+    DF->getFixups().push_back(Fixups[i]);
   }
   DF->getContents().append(Code.begin(), Code.end());
 }
diff --git a/llvm/lib/MC/MCMachOStreamer.cpp b/llvm/lib/MC/MCMachOStreamer.cpp
index cc6c853..f279e74 100644
--- a/llvm/lib/MC/MCMachOStreamer.cpp
+++ b/llvm/lib/MC/MCMachOStreamer.cpp
@@ -368,7 +368,7 @@
   // Add the fixups and data.
   for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
     Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
-    DF->addFixup(Fixups[i]);
+    DF->getFixups().push_back(Fixups[i]);
   }
   DF->getContents().append(Code.begin(), Code.end());
 }
diff --git a/llvm/lib/MC/MCObjectStreamer.cpp b/llvm/lib/MC/MCObjectStreamer.cpp
index 08200eb..c2171ff 100644
--- a/llvm/lib/MC/MCObjectStreamer.cpp
+++ b/llvm/lib/MC/MCObjectStreamer.cpp
@@ -99,9 +99,9 @@
     EmitIntValue(AbsValue, Size, AddrSpace);
     return;
   }
-  DF->addFixup(MCFixup::Create(DF->getContents().size(),
-                               Value,
-                               MCFixup::getKindForSize(Size, false)));
+  DF->getFixups().push_back(
+      MCFixup::Create(DF->getContents().size(), Value,
+                      MCFixup::getKindForSize(Size, false)));
   DF->getContents().resize(DF->getContents().size() + Size, 0);
 }
 
@@ -204,7 +204,7 @@
   raw_svector_ostream VecOS(Code);
   getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, IF->getFixups());
   VecOS.flush();
-  IF->getCode().append(Code.begin(), Code.end());
+  IF->getContents().append(Code.begin(), Code.end());
 }
 
 void MCObjectStreamer::EmitDwarfAdvanceLineAddr(int64_t LineDelta,
@@ -288,7 +288,8 @@
 void MCObjectStreamer::EmitGPRel32Value(const MCExpr *Value) {
   MCDataFragment *DF = getOrCreateDataFragment();
 
-  DF->addFixup(MCFixup::Create(DF->getContents().size(), Value, FK_GPRel_4));
+  DF->getFixups().push_back(MCFixup::Create(DF->getContents().size(), 
+                                            Value, FK_GPRel_4));
   DF->getContents().resize(DF->getContents().size() + 4, 0);
 }
 
@@ -296,7 +297,8 @@
 void MCObjectStreamer::EmitGPRel64Value(const MCExpr *Value) {
   MCDataFragment *DF = getOrCreateDataFragment();
 
-  DF->addFixup(MCFixup::Create(DF->getContents().size(), Value, FK_GPRel_4));
+  DF->getFixups().push_back(MCFixup::Create(DF->getContents().size(), 
+                                            Value, FK_GPRel_4));
   DF->getContents().resize(DF->getContents().size() + 8, 0);
 }
 
diff --git a/llvm/lib/MC/MCPureStreamer.cpp b/llvm/lib/MC/MCPureStreamer.cpp
index fd9ccf7..1563bdd 100644
--- a/llvm/lib/MC/MCPureStreamer.cpp
+++ b/llvm/lib/MC/MCPureStreamer.cpp
@@ -194,7 +194,7 @@
   getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
   VecOS.flush();
 
-  IF->getCode() = Code;
+  IF->getContents() = Code;
   IF->getFixups() = Fixups;
 }
 
@@ -210,7 +210,7 @@
   // Add the fixups and data.
   for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
     Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
-    DF->addFixup(Fixups[i]);
+    DF->getFixups().push_back(Fixups[i]);
   }
   DF->getContents().append(Code.begin(), Code.end());
 }
diff --git a/llvm/lib/MC/WinCOFFStreamer.cpp b/llvm/lib/MC/WinCOFFStreamer.cpp
index 8c8ae3f..359b388 100644
--- a/llvm/lib/MC/WinCOFFStreamer.cpp
+++ b/llvm/lib/MC/WinCOFFStreamer.cpp
@@ -288,9 +288,10 @@
 {
   MCDataFragment *DF = getOrCreateDataFragment();
 
-  DF->addFixup(MCFixup::Create(DF->getContents().size(),
-                               MCSymbolRefExpr::Create (Symbol, getContext ()),
-                               FK_SecRel_4));
+  DF->getFixups().push_back(
+      MCFixup::Create(DF->getContents().size(),
+                      MCSymbolRefExpr::Create (Symbol, getContext ()),
+                      FK_SecRel_4));
   DF->getContents().resize(DF->getContents().size() + 4, 0);
 }
 
@@ -339,7 +340,7 @@
   MCInstFragment *Fragment =
     new MCInstFragment(Instruction, getCurrentSectionData());
 
-  raw_svector_ostream VecOS(Fragment->getCode());
+  raw_svector_ostream VecOS(Fragment->getContents());
 
   getAssembler().getEmitter().EncodeInstruction(Instruction, VecOS,
                                                 Fragment->getFixups());