Cherry-pick r234714: [MC] Write padding into fragments when -mc-relax-all flag is used

lib/MC/MCObjectStreamer.cpp

 //===- lib/MC/MCObjectStreamer.cpp - Object File MCStreamer Interface -----===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/MC/MCObjectStreamer.h"
@@ skipping 24 matching lines @@
     : MCStreamer(Context), Assembler(_Assembler), CurSectionData(nullptr),
       EmitEHFrame(true), EmitDebugFrame(false) {}
 
 MCObjectStreamer::~MCObjectStreamer() {
   delete &Assembler->getBackend();
   delete &Assembler->getEmitter();
   delete &Assembler->getWriter();
   delete Assembler;
 }
 
-void MCObjectStreamer::flushPendingLabels(MCFragment *F) {
+void MCObjectStreamer::flushPendingLabels(MCFragment *F, uint64_t FOffset) {
   if (PendingLabels.size()) {
     if (!F) {
       F = new MCDataFragment();
       CurSectionData->getFragmentList().insert(CurInsertionPoint, F);
       F->setParent(CurSectionData);
     }
     for (MCSymbolData *SD : PendingLabels) {
       SD->setFragment(F);
-      SD->setOffset(0);
+      SD->setOffset(FOffset);
     }
     PendingLabels.clear();
   }
 }
 
 void MCObjectStreamer::reset() {
   if (Assembler)
     Assembler->reset();
   CurSectionData = nullptr;
   CurInsertionPoint = MCSectionData::iterator();
@@ skipping 20 matching lines @@
   if (CurInsertionPoint != getCurrentSectionData()->getFragmentList().begin())
     return std::prev(CurInsertionPoint);
 
   return nullptr;
 }
 
 MCDataFragment *MCObjectStreamer::getOrCreateDataFragment() {
   MCDataFragment *F = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
   // When bundling is enabled, we don't want to add data to a fragment that
   // already has instructions (see MCELFStreamer::EmitInstToData for details)
-  if (!F || (Assembler->isBundlingEnabled() && F->hasInstructions())) {
+  if (!F || (Assembler->isBundlingEnabled() && !Assembler->getRelaxAll() &&
+             F->hasInstructions())) {
     F = new MCDataFragment();
     insert(F);
   }
   return F;
 }
 
 void MCObjectStreamer::visitUsedSymbol(const MCSymbol &Sym) {
   Assembler->getOrCreateSymbolData(Sym);
 }
 
@@ skipping 35 matching lines @@
 
 void MCObjectStreamer::EmitLabel(MCSymbol *Symbol) {
   MCStreamer::EmitLabel(Symbol);
 
   MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
   assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
 
   // If there is a current fragment, mark the symbol as pointing into it.
   // Otherwise queue the label and set its fragment pointer when we emit the
   // next fragment.
-  if (auto *F = dyn_cast_or_null<MCDataFragment>(getCurrentFragment())) {
+  auto *F = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
+  if (F && !(getAssembler().isBundlingEnabled() &&
+             getAssembler().getRelaxAll())) {
     SD.setFragment(F);
     SD.setOffset(F->getContents().size());
   } else {
     PendingLabels.push_back(&SD);
   }
 }
 
 void MCObjectStreamer::EmitULEB128Value(const MCExpr *Value) {
   int64_t IntValue;
   if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {
@@ skipping 78 matching lines @@
     EmitInstToData(Relaxed, STI);
     return;
   }
 
   // Otherwise emit to a separate fragment.
   EmitInstToFragment(Inst, STI);
 }
 
 void MCObjectStreamer::EmitInstToFragment(const MCInst &Inst,
                                           const MCSubtargetInfo &STI) {
+  if (getAssembler().getRelaxAll() && getAssembler().isBundlingEnabled())
+    llvm_unreachable("All instructions should have already been relaxed");
+
   // Always create a new, separate fragment here, because its size can change
   // during relaxation.
   MCRelaxableFragment *IF = new MCRelaxableFragment(Inst, STI);
   insert(IF);
 
   SmallString<128> Code;
   raw_svector_ostream VecOS(Code);
   getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, IF->getFixups(),
                                                 STI);
   VecOS.flush();
@@ skipping 160 matching lines @@
   // If we are generating dwarf for assembly source files dump out the sections.
   if (getContext().getGenDwarfForAssembly())
     MCGenDwarfInfo::Emit(this);
 
   // Dump out the dwarf file & directory tables and line tables.
   MCDwarfLineTable::Emit(this);
 
   flushPendingLabels(nullptr);
   getAssembler().Finish();
 }