1 files changed, 65 insertions, 70 deletions

diff --git a/llvm/lib/MC/MCObjectStreamer.cpp b/llvm/lib/MC/MCObjectStreamer.cpp
index d5b8f22..f046552 100644
--- a/llvm/lib/MC/MCObjectStreamer.cpp
+++ b/llvm/lib/MC/MCObjectStreamer.cpp
@@ -19,7 +19,6 @@
 #include "llvm/MC/MCObjectWriter.h"
 #include "llvm/MC/MCSection.h"
 #include "llvm/MC/MCSymbol.h"
-#include "llvm/MC/MCValue.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/SourceMgr.h"
 using namespace llvm;
@@ -33,6 +32,7 @@ MCObjectStreamer::MCObjectStreamer(MCContext &Context,
           Context, std::move(TAB), std::move(Emitter), std::move(OW))),
       EmitEHFrame(true), EmitDebugFrame(false) {
   assert(Assembler->getBackendPtr() && Assembler->getEmitterPtr());
+  IsObj = true;
   setAllowAutoPadding(Assembler->getBackend().allowAutoPadding());
   if (Context.getTargetOptions() && Context.getTargetOptions()->MCRelaxAll)
     Assembler->setRelaxAll(true);
@@ -46,6 +46,25 @@ MCAssembler *MCObjectStreamer::getAssemblerPtr() {
   return nullptr;
 }
 
+void MCObjectStreamer::newFragment() {
+  addFragment(getContext().allocFragment<MCFragment>());
+}
+
+void MCObjectStreamer::insert(MCFragment *F) {
+  assert(F->getKind() != MCFragment::FT_Data &&
+         "F should have a variable-size tail");
+  addFragment(F);
+  newFragment();
+}
+
+void MCObjectStreamer::appendContents(size_t Num, char Elt) {
+  CurFrag->appendContents(Num, Elt);
+}
+
+void MCObjectStreamer::addFixup(const MCExpr *Value, MCFixupKind Kind) {
+  CurFrag->addFixup(MCFixup::create(CurFrag->getFixedSize(), Value, Kind));
+}
+
 // As a compile-time optimization, avoid allocating and evaluating an MCExpr
 // tree for (Hi - Lo) when Hi and Lo are offsets into the same fragment's fixed
 // part.
@@ -106,32 +125,21 @@ void MCObjectStreamer::emitFrames(MCAsmBackend *MAB) {
     MCDwarfFrameEmitter::Emit(*this, MAB, false);
 }
 
-MCFragment *MCObjectStreamer::getOrCreateDataFragment() {
-  // TODO: Start a new fragment whenever finalizing the variable-size tail of a
-  // previous one, so that all getOrCreateDataFragment calls can be replaced
-  // with getCurrentFragment
-  auto *F = getCurrentFragment();
-  if (F->getKind() != MCFragment::FT_Data) {
-    F = getContext().allocFragment<MCFragment>();
-    insert(F);
-  }
-  return F;
-}
-
 void MCObjectStreamer::visitUsedSymbol(const MCSymbol &Sym) {
   Assembler->registerSymbol(Sym);
 }
 
-void MCObjectStreamer::emitCFISections(bool EH, bool Debug) {
-  MCStreamer::emitCFISections(EH, Debug);
+void MCObjectStreamer::emitCFISections(bool EH, bool Debug, bool SFrame) {
+  MCStreamer::emitCFISections(EH, Debug, SFrame);
   EmitEHFrame = EH;
   EmitDebugFrame = Debug;
+  EmitSFrame = SFrame;
 }
 
 void MCObjectStreamer::emitValueImpl(const MCExpr *Value, unsigned Size,
                                      SMLoc Loc) {
   MCStreamer::emitValueImpl(Value, Size, Loc);
-  MCFragment *DF = getOrCreateDataFragment();
+  MCFragment *DF = getCurrentFragment();
 
   MCDwarfLineEntry::make(this, getCurrentSectionOnly());
 
@@ -177,10 +185,10 @@ void MCObjectStreamer::emitLabel(MCSymbol *Symbol, SMLoc Loc) {
 
   getAssembler().registerSymbol(*Symbol);
 
-  // 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.
-  MCFragment *F = getOrCreateDataFragment();
+  // Set the fragment and offset. This function might be called by
+  // changeSection, when the section stack top hasn't been changed to the new
+  // section.
+  MCFragment *F = CurFrag;
   Symbol->setFragment(F);
   Symbol->setOffset(F->getContents().size());
 
@@ -214,10 +222,9 @@ void MCObjectStreamer::emitULEB128Value(const MCExpr *Value) {
     emitULEB128IntValue(IntValue);
     return;
   }
-  auto *F = getOrCreateDataFragment();
-  F->Kind = MCFragment::FT_LEB;
-  F->setLEBSigned(false);
-  F->setLEBValue(Value);
+  auto *F = getCurrentFragment();
+  F->makeLEB(false, Value);
+  newFragment();
 }
 
 void MCObjectStreamer::emitSLEB128Value(const MCExpr *Value) {
@@ -226,10 +233,9 @@ void MCObjectStreamer::emitSLEB128Value(const MCExpr *Value) {
     emitSLEB128IntValue(IntValue);
     return;
   }
-  auto *F = getOrCreateDataFragment();
-  F->Kind = MCFragment::FT_LEB;
-  F->setLEBSigned(true);
-  F->setLEBValue(Value);
+  auto *F = getCurrentFragment();
+  F->makeLEB(true, Value);
+  newFragment();
 }
 
 void MCObjectStreamer::emitWeakReference(MCSymbol *Alias,
@@ -238,14 +244,18 @@ void MCObjectStreamer::emitWeakReference(MCSymbol *Alias,
 }
 
 void MCObjectStreamer::changeSection(MCSection *Section, uint32_t Subsection) {
-  changeSectionImpl(Section, Subsection);
-}
-
-bool MCObjectStreamer::changeSectionImpl(MCSection *Section,
-                                         uint32_t Subsection) {
   assert(Section && "Cannot switch to a null section!");
   getContext().clearDwarfLocSeen();
 
+  // Register the section and create an initial fragment for subsection 0
+  // if `Subsection` is non-zero.
+  bool NewSec = getAssembler().registerSection(*Section);
+  MCFragment *F0 = nullptr;
+  if (NewSec && Subsection) {
+    changeSection(Section, 0);
+    F0 = CurFrag;
+  }
+
   auto &Subsections = Section->Subsections;
   size_t I = 0, E = Subsections.size();
   while (I != E && Subsections[I].first < Subsection)
@@ -261,12 +271,13 @@ bool MCObjectStreamer::changeSectionImpl(MCSection *Section,
   Section->CurFragList = &Subsections[I].second;
   CurFrag = Section->CurFragList->Tail;
 
-  return getAssembler().registerSection(*Section);
-}
-
-void MCObjectStreamer::switchSectionNoPrint(MCSection *Section) {
-  MCStreamer::switchSectionNoPrint(Section);
-  changeSection(Section, 0);
+  // Define the section symbol at subsection 0's initial fragment if required.
+  if (!NewSec)
+    return;
+  if (auto *Sym = Section->getBeginSymbol()) {
+    Sym->setFragment(Subsection ? F0 : CurFrag);
+    getAssembler().registerSymbol(*Sym);
+  }
 }
 
 void MCObjectStreamer::emitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
@@ -293,18 +304,6 @@ bool MCObjectStreamer::mayHaveInstructions(MCSection &Sec) const {
 
 void MCObjectStreamer::emitInstruction(const MCInst &Inst,
                                        const MCSubtargetInfo &STI) {
-  const MCSection &Sec = *getCurrentSectionOnly();
-  if (Sec.isVirtualSection()) {
-    getContext().reportError(Inst.getLoc(), Twine(Sec.getVirtualSectionKind()) +
-                                                " section '" + Sec.getName() +
-                                                "' cannot have instructions");
-    return;
-  }
-  emitInstructionImpl(Inst, STI);
-}
-
-void MCObjectStreamer::emitInstructionImpl(const MCInst &Inst,
-                                           const MCSubtargetInfo &STI) {
   MCStreamer::emitInstruction(Inst, STI);
 
   MCSection *Sec = getCurrentSectionOnly();
@@ -338,7 +337,7 @@ void MCObjectStreamer::emitInstructionImpl(const MCInst &Inst,
 
 void MCObjectStreamer::emitInstToData(const MCInst &Inst,
                                       const MCSubtargetInfo &STI) {
-  MCFragment *F = getOrCreateDataFragment();
+  MCFragment *F = getCurrentFragment();
 
   // Append the instruction to the data fragment.
   size_t FixupStartIndex = F->getFixups().size();
@@ -370,7 +369,7 @@ void MCObjectStreamer::emitInstToData(const MCInst &Inst,
 
 void MCObjectStreamer::emitInstToFragment(const MCInst &Inst,
                                           const MCSubtargetInfo &STI) {
-  auto *F = getOrCreateDataFragment();
+  auto *F = getCurrentFragment();
   SmallVector<char, 16> Data;
   SmallVector<MCFixup, 1> Fixups;
   getAssembler().getEmitter().encodeInstruction(Inst, Data, Fixups, STI);
@@ -381,6 +380,7 @@ void MCObjectStreamer::emitInstToFragment(const MCInst &Inst,
   F->setVarContents(Data);
   F->setVarFixups(Fixups);
   F->setInst(Inst);
+  newFragment();
 }
 
 void MCObjectStreamer::emitDwarfLocDirective(unsigned FileNo, unsigned Line,
@@ -442,10 +442,11 @@ void MCObjectStreamer::emitDwarfAdvanceLineAddr(int64_t LineDelta,
     return;
   }
 
-  auto *F = getOrCreateDataFragment();
+  auto *F = getCurrentFragment();
   F->Kind = MCFragment::FT_Dwarf;
   F->setDwarfAddrDelta(buildSymbolDiff(*this, Label, LastLabel, SMLoc()));
   F->setDwarfLineDelta(LineDelta);
+  newFragment();
 }
 
 void MCObjectStreamer::emitDwarfLineEndEntry(MCSection *Section,
@@ -473,9 +474,10 @@ void MCObjectStreamer::emitDwarfLineEndEntry(MCSection *Section,
 void MCObjectStreamer::emitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
                                                  const MCSymbol *Label,
                                                  SMLoc Loc) {
-  auto *F = getOrCreateDataFragment();
+  auto *F = getCurrentFragment();
   F->Kind = MCFragment::FT_DwarfFrame;
   F->setDwarfAddrDelta(buildSymbolDiff(*this, Label, LastLabel, Loc));
+  newFragment();
 }
 
 void MCObjectStreamer::emitCVLocDirective(unsigned FunctionId, unsigned FileNo,
@@ -534,7 +536,7 @@ void MCObjectStreamer::emitCVFileChecksumOffsetDirective(unsigned FileNo) {
 
 void MCObjectStreamer::emitBytes(StringRef Data) {
   MCDwarfLineEntry::make(this, getCurrentSectionOnly());
-  MCFragment *DF = getOrCreateDataFragment();
+  MCFragment *DF = getCurrentFragment();
   DF->appendContents(ArrayRef(Data.data(), Data.size()));
 }
 
@@ -543,28 +545,21 @@ void MCObjectStreamer::emitValueToAlignment(Align Alignment, int64_t Fill,
                                             unsigned MaxBytesToEmit) {
   if (MaxBytesToEmit == 0)
     MaxBytesToEmit = Alignment.value();
-  insert(getContext().allocFragment<MCAlignFragment>(Alignment, Fill, FillLen,
-                                                     MaxBytesToEmit));
+  MCFragment *F = getCurrentFragment();
+  F->makeAlign(Alignment, Fill, FillLen, MaxBytesToEmit);
+  newFragment();
 
   // Update the maximum alignment on the current section if necessary.
-  MCSection *CurSec = getCurrentSectionOnly();
-  CurSec->ensureMinAlignment(Alignment);
+  F->getParent()->ensureMinAlignment(Alignment);
 }
 
 void MCObjectStreamer::emitCodeAlignment(Align Alignment,
                                          const MCSubtargetInfo *STI,
                                          unsigned MaxBytesToEmit) {
+  auto *F = getCurrentFragment();
   emitValueToAlignment(Alignment, 0, 1, MaxBytesToEmit);
-  auto *F = cast<MCAlignFragment>(getCurrentFragment());
-  F->setEmitNops(true, STI);
-  // With RISC-V style linker relaxation, mark the section as linker-relaxable
-  // if the alignment is larger than the minimum NOP size.
-  unsigned Size;
-  if (getAssembler().getBackend().shouldInsertExtraNopBytesForCodeAlign(*F,
-                                                                        Size)) {
-    getCurrentSectionOnly()->setLinkerRelaxable();
-    newFragment();
-  }
+  F->u.align.EmitNops = true;
+  F->STI = STI;
 }
 
 void MCObjectStreamer::emitValueToOffset(const MCExpr *Offset,