1 files changed, 169 insertions, 179 deletions

diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 5f67d3daa97f..272baceeed89 100644
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -12,11 +12,10 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/CodeGen/AsmPrinter.h"
+#include "CodeViewDebug.h"
 #include "DwarfDebug.h"
 #include "DwarfException.h"
 #include "WinException.h"
-#include "WinCodeViewLineTables.h"
-#include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/ConstantFolding.h"
 #include "llvm/CodeGen/Analysis.h"
@@ -125,6 +124,10 @@ AsmPrinter::~AsmPrinter() {
   }
 }
 
+bool AsmPrinter::isPositionIndependent() const {
+  return TM.isPositionIndependent();
+}
+
 /// getFunctionNumber - Return a unique ID for the current function.
 ///
 unsigned AsmPrinter::getFunctionNumber() const {
@@ -248,12 +251,13 @@ bool AsmPrinter::doInitialization(Module &M) {
   if (MAI->doesSupportDebugInformation()) {
     bool EmitCodeView = MMI->getModule()->getCodeViewFlag();
     if (EmitCodeView && TM.getTargetTriple().isKnownWindowsMSVCEnvironment()) {
-      Handlers.push_back(HandlerInfo(new WinCodeViewLineTables(this),
+      Handlers.push_back(HandlerInfo(new CodeViewDebug(this),
                                      DbgTimerName,
                                      CodeViewLineTablesGroupName));
     }
     if (!EmitCodeView || MMI->getModule()->getDwarfVersion()) {
       DD = new DwarfDebug(this, &M);
+      DD->beginModule();
       Handlers.push_back(HandlerInfo(DD, DbgTimerName, DWARFGroupName));
     }
   }
@@ -319,21 +323,17 @@ void AsmPrinter::EmitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const {
       OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Weak);
     }
     return;
-  case GlobalValue::AppendingLinkage:
-    // FIXME: appending linkage variables should go into a section of
-    // their name or something.  For now, just emit them as external.
   case GlobalValue::ExternalLinkage:
-    // If external or appending, declare as a global symbol.
-    // .globl _foo
+    // If external, declare as a global symbol: .globl _foo
     OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
     return;
   case GlobalValue::PrivateLinkage:
   case GlobalValue::InternalLinkage:
     return;
+  case GlobalValue::AppendingLinkage:
   case GlobalValue::AvailableExternallyLinkage:
-    llvm_unreachable("Should never emit this");
   case GlobalValue::ExternalWeakLinkage:
-    llvm_unreachable("Don't know how to emit these");
+    llvm_unreachable("Should never emit this");
   }
   llvm_unreachable("Unknown linkage type!");
 }
@@ -347,51 +347,17 @@ MCSymbol *AsmPrinter::getSymbol(const GlobalValue *GV) const {
   return TM.getSymbol(GV, *Mang);
 }
 
-static MCSymbol *getOrCreateEmuTLSControlSym(MCSymbol *GVSym, MCContext &C) {
-  return C.getOrCreateSymbol(Twine("__emutls_v.") + GVSym->getName());
-}
-
-static MCSymbol *getOrCreateEmuTLSInitSym(MCSymbol *GVSym, MCContext &C) {
-  return C.getOrCreateSymbol(Twine("__emutls_t.") + GVSym->getName());
-}
-
-/// EmitEmulatedTLSControlVariable - Emit the control variable for an emulated TLS variable.
-void AsmPrinter::EmitEmulatedTLSControlVariable(const GlobalVariable *GV,
-                                                MCSymbol *EmittedSym,
-                                                bool AllZeroInitValue) {
-  MCSection *TLSVarSection = getObjFileLowering().getDataSection();
-  OutStreamer->SwitchSection(TLSVarSection);
-  MCSymbol *GVSym = getSymbol(GV);
-  EmitLinkage(GV, EmittedSym);  // same linkage as GV
-  const DataLayout &DL = GV->getParent()->getDataLayout();
-  uint64_t Size = DL.getTypeAllocSize(GV->getType()->getElementType());
-  unsigned AlignLog = getGVAlignmentLog2(GV, DL);
-  unsigned WordSize = DL.getPointerSize();
-  unsigned Alignment = DL.getPointerABIAlignment();
-  EmitAlignment(Log2_32(Alignment));
-  OutStreamer->EmitLabel(EmittedSym);
-  OutStreamer->EmitIntValue(Size, WordSize);
-  OutStreamer->EmitIntValue((1 << AlignLog), WordSize);
-  OutStreamer->EmitIntValue(0, WordSize);
-  if (GV->hasInitializer() && !AllZeroInitValue) {
-    OutStreamer->EmitSymbolValue(
-        getOrCreateEmuTLSInitSym(GVSym, OutContext), WordSize);
-  } else
-    OutStreamer->EmitIntValue(0, WordSize);
-  if (MAI->hasDotTypeDotSizeDirective())
-    OutStreamer->emitELFSize(cast<MCSymbolELF>(EmittedSym),
-                             MCConstantExpr::create(4 * WordSize, OutContext));
-  OutStreamer->AddBlankLine();  // End of the __emutls_v.* variable.
-}
-
 /// EmitGlobalVariable - Emit the specified global variable to the .s file.
 void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
-  bool IsEmuTLSVar =
-      GV->getThreadLocalMode() != llvm::GlobalVariable::NotThreadLocal &&
-      TM.Options.EmulatedTLS;
+  bool IsEmuTLSVar = TM.Options.EmulatedTLS && GV->isThreadLocal();
   assert(!(IsEmuTLSVar && GV->hasCommonLinkage()) &&
          "No emulated TLS variables in the common section");
 
+  // Never emit TLS variable xyz in emulated TLS model.
+  // The initialization value is in __emutls_t.xyz instead of xyz.
+  if (IsEmuTLSVar)
+    return;
+
   if (GV->hasInitializer()) {
     // Check to see if this is a special global used by LLVM, if so, emit it.
     if (EmitSpecialLLVMGlobal(GV))
@@ -402,7 +368,7 @@ void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
     if (GlobalGOTEquivs.count(getSymbol(GV)))
       return;
 
-    if (isVerbose() && !IsEmuTLSVar) {
+    if (isVerbose()) {
       // When printing the control variable __emutls_v.*,
       // we don't need to print the original TLS variable name.
       GV->printAsOperand(OutStreamer->GetCommentOS(),
@@ -412,11 +378,11 @@ void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
   }
 
   MCSymbol *GVSym = getSymbol(GV);
-  MCSymbol *EmittedSym = IsEmuTLSVar ?
-      getOrCreateEmuTLSControlSym(GVSym, OutContext) : GVSym;
-  // getOrCreateEmuTLSControlSym only creates the symbol with name and default attributes.
-  // GV's or GVSym's attributes will be used for the EmittedSym.
+  MCSymbol *EmittedSym = GVSym;
 
+  // getOrCreateEmuTLSControlSym only creates the symbol with name and default
+  // attributes.
+  // GV's or GVSym's attributes will be used for the EmittedSym.
   EmitVisibility(EmittedSym, GV->getVisibility(), !GV->isDeclaration());
 
   if (!GV->hasInitializer())   // External globals require no extra code.
@@ -440,48 +406,47 @@ void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
   // sections and expected to be contiguous (e.g. ObjC metadata).
   unsigned AlignLog = getGVAlignmentLog2(GV, DL);
 
-  bool AllZeroInitValue = false;
-  const Constant *InitValue = GV->getInitializer();
-  if (isa<ConstantAggregateZero>(InitValue))
-    AllZeroInitValue = true;
-  else {
-    const ConstantInt *InitIntValue = dyn_cast<ConstantInt>(InitValue);
-    if (InitIntValue && InitIntValue->isZero())
-      AllZeroInitValue = true;
-  }
-  if (IsEmuTLSVar)
-    EmitEmulatedTLSControlVariable(GV, EmittedSym, AllZeroInitValue);
-
   for (const HandlerInfo &HI : Handlers) {
     NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
     HI.Handler->setSymbolSize(GVSym, Size);
   }
 
-  // Handle common and BSS local symbols (.lcomm).
-  if (GVKind.isCommon() || GVKind.isBSSLocal()) {
-    assert(!(IsEmuTLSVar && GVKind.isCommon()) &&
-           "No emulated TLS variables in the common section");
+  // Handle common symbols
+  if (GVKind.isCommon()) {
     if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
     unsigned Align = 1 << AlignLog;
+    if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
+      Align = 0;
 
-    // Handle common symbols.
-    if (GVKind.isCommon()) {
-      if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
-        Align = 0;
+    // .comm _foo, 42, 4
+    OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
+    return;
+  }
 
-      // .comm _foo, 42, 4
-      OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
-      return;
-    }
+  // Determine to which section this global should be emitted.
+  MCSection *TheSection =
+      getObjFileLowering().SectionForGlobal(GV, GVKind, *Mang, TM);
 
-    // Handle local BSS symbols.
-    if (MAI->hasMachoZeroFillDirective()) {
-      MCSection *TheSection =
-          getObjFileLowering().SectionForGlobal(GV, GVKind, *Mang, TM);
-      // .zerofill __DATA, __bss, _foo, 400, 5
-      OutStreamer->EmitZerofill(TheSection, GVSym, Size, Align);
-      return;
-    }
+  // If we have a bss global going to a section that supports the
+  // zerofill directive, do so here.
+  if (GVKind.isBSS() && MAI->hasMachoZeroFillDirective() &&
+      TheSection->isVirtualSection()) {
+    if (Size == 0)
+      Size = 1; // zerofill of 0 bytes is undefined.
+    unsigned Align = 1 << AlignLog;
+    EmitLinkage(GV, GVSym);
+    // .zerofill __DATA, __bss, _foo, 400, 5
+    OutStreamer->EmitZerofill(TheSection, GVSym, Size, Align);
+    return;
+  }
+
+  // If this is a BSS local symbol and we are emitting in the BSS
+  // section use .lcomm/.comm directive.
+  if (GVKind.isBSSLocal() &&
+      getObjFileLowering().getBSSSection() == TheSection) {
+    if (Size == 0)
+      Size = 1; // .comm Foo, 0 is undefined, avoid it.
+    unsigned Align = 1 << AlignLog;
 
     // Use .lcomm only if it supports user-specified alignment.
     // Otherwise, while it would still be correct to use .lcomm in some
@@ -505,30 +470,6 @@ void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
     return;
   }
 
-  if (IsEmuTLSVar && AllZeroInitValue)
-    return;  // No need of initialization values.
-
-  MCSymbol *EmittedInitSym = IsEmuTLSVar ?
-      getOrCreateEmuTLSInitSym(GVSym, OutContext) : GVSym;
-  // getOrCreateEmuTLSInitSym only creates the symbol with name and default attributes.
-  // GV's or GVSym's attributes will be used for the EmittedInitSym.
-
-  MCSection *TheSection = IsEmuTLSVar ?
-      getObjFileLowering().getReadOnlySection() :
-      getObjFileLowering().SectionForGlobal(GV, GVKind, *Mang, TM);
-
-  // Handle the zerofill directive on darwin, which is a special form of BSS
-  // emission.
-  if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective() && !IsEmuTLSVar) {
-    if (Size == 0) Size = 1;  // zerofill of 0 bytes is undefined.
-
-    // .globl _foo
-    OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
-    // .zerofill __DATA, __common, _foo, 400, 5
-    OutStreamer->EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
-    return;
-  }
-
   // Handle thread local data for mach-o which requires us to output an
   // additional structure of data and mangle the original symbol so that we
   // can reference it later.
@@ -539,7 +480,7 @@ void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
   // TLOF class.  This will also make it more obvious that stuff like
   // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho
   // specific code.
-  if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective() && !IsEmuTLSVar) {
+  if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) {
     // Emit the .tbss symbol
     MCSymbol *MangSym =
       OutContext.getOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));
@@ -581,11 +522,11 @@ void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
     return;
   }
 
+  MCSymbol *EmittedInitSym = GVSym;
+
   OutStreamer->SwitchSection(TheSection);
 
-  // emutls_t.* symbols are only used in the current compilation unit.
-  if (!IsEmuTLSVar)
-    EmitLinkage(GV, EmittedInitSym);
+  EmitLinkage(GV, EmittedInitSym);
   EmitAlignment(AlignLog, GV);
 
   OutStreamer->EmitLabel(EmittedInitSym);
@@ -696,20 +637,20 @@ static void emitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
   // We assume a single instruction only has a spill or reload, not
   // both.
   const MachineMemOperand *MMO;
-  if (TII->isLoadFromStackSlotPostFE(&MI, FI)) {
+  if (TII->isLoadFromStackSlotPostFE(MI, FI)) {
     if (FrameInfo->isSpillSlotObjectIndex(FI)) {
       MMO = *MI.memoperands_begin();
       CommentOS << MMO->getSize() << "-byte Reload\n";
     }
-  } else if (TII->hasLoadFromStackSlot(&MI, MMO, FI)) {
+  } else if (TII->hasLoadFromStackSlot(MI, MMO, FI)) {
     if (FrameInfo->isSpillSlotObjectIndex(FI))
       CommentOS << MMO->getSize() << "-byte Folded Reload\n";
-  } else if (TII->isStoreToStackSlotPostFE(&MI, FI)) {
+  } else if (TII->isStoreToStackSlotPostFE(MI, FI)) {
     if (FrameInfo->isSpillSlotObjectIndex(FI)) {
       MMO = *MI.memoperands_begin();
       CommentOS << MMO->getSize() << "-byte Spill\n";
     }
-  } else if (TII->hasStoreToStackSlot(&MI, MMO, FI)) {
+  } else if (TII->hasStoreToStackSlot(MI, MMO, FI)) {
     if (FrameInfo->isSpillSlotObjectIndex(FI))
       CommentOS << MMO->getSize() << "-byte Folded Spill\n";
   }
@@ -745,7 +686,7 @@ static void emitKill(const MachineInstr *MI, AsmPrinter &AP) {
                    AP.MF->getSubtarget().getRegisterInfo())
        << (Op.isDef() ? "<def>" : "<kill>");
   }
-  AP.OutStreamer->AddComment(Str);
+  AP.OutStreamer->AddComment(OS.str());
   AP.OutStreamer->AddBlankLine();
 }
 
@@ -1065,8 +1006,9 @@ static bool isGOTEquivalentCandidate(const GlobalVariable *GV,
   // Global GOT equivalents are unnamed private globals with a constant
   // pointer initializer to another global symbol. They must point to a
   // GlobalVariable or Function, i.e., as GlobalValue.
-  if (!GV->hasUnnamedAddr() || !GV->hasInitializer() || !GV->isConstant() ||
-      !GV->isDiscardableIfUnused() || !dyn_cast<GlobalValue>(GV->getOperand(0)))
+  if (!GV->hasGlobalUnnamedAddr() || !GV->hasInitializer() ||
+      !GV->isConstant() || !GV->isDiscardableIfUnused() ||
+      !dyn_cast<GlobalValue>(GV->getOperand(0)))
     return false;
 
   // To be a got equivalent, at least one of its users need to be a constant
@@ -1118,6 +1060,52 @@ void AsmPrinter::emitGlobalGOTEquivs() {
     EmitGlobalVariable(GV);
 }
 
+void AsmPrinter::emitGlobalIndirectSymbol(Module &M,
+                                          const GlobalIndirectSymbol& GIS) {
+  MCSymbol *Name = getSymbol(&GIS);
+
+  if (GIS.hasExternalLinkage() || !MAI->getWeakRefDirective())
+    OutStreamer->EmitSymbolAttribute(Name, MCSA_Global);
+  else if (GIS.hasWeakLinkage() || GIS.hasLinkOnceLinkage())
+    OutStreamer->EmitSymbolAttribute(Name, MCSA_WeakReference);
+  else
+    assert(GIS.hasLocalLinkage() && "Invalid alias or ifunc linkage");
+
+  // Set the symbol type to function if the alias has a function type.
+  // This affects codegen when the aliasee is not a function.
+  if (GIS.getType()->getPointerElementType()->isFunctionTy()) {
+    OutStreamer->EmitSymbolAttribute(Name, MCSA_ELF_TypeFunction);
+    if (isa<GlobalIFunc>(GIS))
+      OutStreamer->EmitSymbolAttribute(Name, MCSA_ELF_TypeIndFunction);
+  }
+
+  EmitVisibility(Name, GIS.getVisibility());
+
+  const MCExpr *Expr = lowerConstant(GIS.getIndirectSymbol());
+
+  if (isa<GlobalAlias>(&GIS) && MAI->hasAltEntry() && isa<MCBinaryExpr>(Expr))
+    OutStreamer->EmitSymbolAttribute(Name, MCSA_AltEntry);
+
+  // Emit the directives as assignments aka .set:
+  OutStreamer->EmitAssignment(Name, Expr);
+
+  if (auto *GA = dyn_cast<GlobalAlias>(&GIS)) {
+    // If the aliasee does not correspond to a symbol in the output, i.e. the
+    // alias is not of an object or the aliased object is private, then set the
+    // size of the alias symbol from the type of the alias. We don't do this in
+    // other situations as the alias and aliasee having differing types but same
+    // size may be intentional.
+    const GlobalObject *BaseObject = GA->getBaseObject();
+    if (MAI->hasDotTypeDotSizeDirective() && GA->getValueType()->isSized() &&
+        (!BaseObject || BaseObject->hasPrivateLinkage())) {
+      const DataLayout &DL = M.getDataLayout();
+      uint64_t Size = DL.getTypeAllocSize(GA->getValueType());
+      OutStreamer->emitELFSize(cast<MCSymbolELF>(Name),
+                               MCConstantExpr::create(Size, OutContext));
+    }
+  }
+}
+
 bool AsmPrinter::doFinalization(Module &M) {
   // Set the MachineFunction to nullptr so that we can catch attempted
   // accesses to MF specific features at the module level and so that
@@ -1191,55 +1179,35 @@ bool AsmPrinter::doFinalization(Module &M) {
     // to notice uses in operands (due to constant exprs etc).  This should
     // happen with the MC stuff eventually.
 
-    // Print out module-level global variables here.
-    for (const auto &G : M.globals()) {
-      if (!G.hasExternalWeakLinkage())
+    // Print out module-level global objects here.
+    for (const auto &GO : M.global_objects()) {
+      if (!GO.hasExternalWeakLinkage())
         continue;
-      OutStreamer->EmitSymbolAttribute(getSymbol(&G), MCSA_WeakReference);
-    }
-
-    for (const auto &F : M) {
-      if (!F.hasExternalWeakLinkage())
-        continue;
-      OutStreamer->EmitSymbolAttribute(getSymbol(&F), MCSA_WeakReference);
+      OutStreamer->EmitSymbolAttribute(getSymbol(&GO), MCSA_WeakReference);
     }
   }
 
   OutStreamer->AddBlankLine();
-  for (const auto &Alias : M.aliases()) {
-    MCSymbol *Name = getSymbol(&Alias);
-
-    if (Alias.hasExternalLinkage() || !MAI->getWeakRefDirective())
-      OutStreamer->EmitSymbolAttribute(Name, MCSA_Global);
-    else if (Alias.hasWeakLinkage() || Alias.hasLinkOnceLinkage())
-      OutStreamer->EmitSymbolAttribute(Name, MCSA_WeakReference);
-    else
-      assert(Alias.hasLocalLinkage() && "Invalid alias linkage");
-
-    // Set the symbol type to function if the alias has a function type.
-    // This affects codegen when the aliasee is not a function.
-    if (Alias.getType()->getPointerElementType()->isFunctionTy())
-      OutStreamer->EmitSymbolAttribute(Name, MCSA_ELF_TypeFunction);
-
-    EmitVisibility(Name, Alias.getVisibility());
 
-    // Emit the directives as assignments aka .set:
-    OutStreamer->EmitAssignment(Name, lowerConstant(Alias.getAliasee()));
-
-    // If the aliasee does not correspond to a symbol in the output, i.e. the
-    // alias is not of an object or the aliased object is private, then set the
-    // size of the alias symbol from the type of the alias. We don't do this in
-    // other situations as the alias and aliasee having differing types but same
-    // size may be intentional.
-    const GlobalObject *BaseObject = Alias.getBaseObject();
-    if (MAI->hasDotTypeDotSizeDirective() && Alias.getValueType()->isSized() &&
-        (!BaseObject || BaseObject->hasPrivateLinkage())) {
-      const DataLayout &DL = M.getDataLayout();
-      uint64_t Size = DL.getTypeAllocSize(Alias.getValueType());
-      OutStreamer->emitELFSize(cast<MCSymbolELF>(Name),
-                               MCConstantExpr::create(Size, OutContext));
+  // Print aliases in topological order, that is, for each alias a = b,
+  // b must be printed before a.
+  // This is because on some targets (e.g. PowerPC) linker expects aliases in
+  // such an order to generate correct TOC information.
+  SmallVector<const GlobalAlias *, 16> AliasStack;
+  SmallPtrSet<const GlobalAlias *, 16> AliasVisited;
+  for (const auto &Alias : M.aliases()) {
+    for (const GlobalAlias *Cur = &Alias; Cur;
+         Cur = dyn_cast<GlobalAlias>(Cur->getAliasee())) {
+      if (!AliasVisited.insert(Cur).second)
+        break;
+      AliasStack.push_back(Cur);
     }
+    for (const GlobalAlias *AncestorAlias : reverse(AliasStack))
+      emitGlobalIndirectSymbol(M, *AncestorAlias);
+    AliasStack.clear();
   }
+  for (const auto &IFunc : M.ifuncs())
+    emitGlobalIndirectSymbol(M, IFunc);
 
   GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
   assert(MI && "AsmPrinter didn't require GCModuleInfo?");
@@ -1252,9 +1220,10 @@ bool AsmPrinter::doFinalization(Module &M) {
 
   // Emit __morestack address if needed for indirect calls.
   if (MMI->usesMorestackAddr()) {
+    unsigned Align = 1;
     MCSection *ReadOnlySection = getObjFileLowering().getSectionForConstant(
         getDataLayout(), SectionKind::getReadOnly(),
-        /*C=*/nullptr);
+        /*C=*/nullptr, Align);
     OutStreamer->SwitchSection(ReadOnlySection);
 
     MCSymbol *AddrSymbol =
@@ -1344,8 +1313,8 @@ void AsmPrinter::EmitConstantPool() {
     if (!CPE.isMachineConstantPoolEntry())
       C = CPE.Val.ConstVal;
 
-    MCSection *S =
-        getObjFileLowering().getSectionForConstant(getDataLayout(), Kind, C);
+    MCSection *S = getObjFileLowering().getSectionForConstant(getDataLayout(),
+                                                              Kind, C, Align);
 
     // The number of sections are small, just do a linear search from the
     // last section to the first.
@@ -1443,7 +1412,7 @@ void AsmPrinter::EmitJumpTableInfo() {
     // For the EK_LabelDifference32 entry, if using .set avoids a relocation,
     /// emit a .set directive for each unique entry.
     if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
-        MAI->doesSetDirectiveSuppressesReloc()) {
+        MAI->doesSetDirectiveSuppressReloc()) {
       SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
       const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
       const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
@@ -1524,7 +1493,7 @@ void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
     // If the .set directive avoids relocations, this is emitted as:
     //      .set L4_5_set_123, LBB123 - LJTI1_2
     //      .word L4_5_set_123
-    if (MAI->doesSetDirectiveSuppressesReloc()) {
+    if (MAI->doesSetDirectiveSuppressReloc()) {
       Value = MCSymbolRefExpr::create(GetJTSetSymbol(UID, MBB->getNumber()),
                                       OutContext);
       break;
@@ -1555,7 +1524,7 @@ bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
   }
 
   // Ignore debug and non-emitted data.  This handles llvm.compiler.used.
-  if (StringRef(GV->getSection()) == "llvm.metadata" ||
+  if (GV->getSection() == "llvm.metadata" ||
       GV->hasAvailableExternallyLinkage())
     return true;
 
@@ -1589,7 +1558,7 @@ bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
     return true;
   }
 
-  return false;
+  report_fatal_error("unknown special variable");
 }
 
 /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
@@ -1648,7 +1617,8 @@ void AsmPrinter::EmitXXStructorList(const DataLayout &DL, const Constant *List,
     S.Priority = Priority->getLimitedValue(65535);
     S.Func = CS->getOperand(1);
     if (ETy->getNumElements() == 3 && !CS->getOperand(2)->isNullValue())
-      S.ComdatKey = dyn_cast<GlobalValue>(CS->getOperand(2)->stripPointerCasts());
+      S.ComdatKey =
+          dyn_cast<GlobalValue>(CS->getOperand(2)->stripPointerCasts());
   }
 
   // Emit the function pointers in the target-specific order
@@ -1789,10 +1759,6 @@ const MCExpr *AsmPrinter::lowerConstant(const Constant *CV) {
     llvm_unreachable("Unknown constant value to lower!");
   }
 
-  if (const MCExpr *RelocExpr
-      = getObjFileLowering().getExecutableRelativeSymbol(CE, *Mang, TM))
-    return RelocExpr;
-
   switch (CE->getOpcode()) {
   default:
     // If the code isn't optimized, there may be outstanding folding
@@ -1868,10 +1834,34 @@ const MCExpr *AsmPrinter::lowerConstant(const Constant *CV) {
     return MCBinaryExpr::createAnd(OpExpr, MaskExpr, Ctx);
   }
 
+  case Instruction::Sub: {
+    GlobalValue *LHSGV;
+    APInt LHSOffset;
+    if (IsConstantOffsetFromGlobal(CE->getOperand(0), LHSGV, LHSOffset,
+                                   getDataLayout())) {
+      GlobalValue *RHSGV;
+      APInt RHSOffset;
+      if (IsConstantOffsetFromGlobal(CE->getOperand(1), RHSGV, RHSOffset,
+                                     getDataLayout())) {
+        const MCExpr *RelocExpr = getObjFileLowering().lowerRelativeReference(
+            LHSGV, RHSGV, *Mang, TM);
+        if (!RelocExpr)
+          RelocExpr = MCBinaryExpr::createSub(
+              MCSymbolRefExpr::create(getSymbol(LHSGV), Ctx),
+              MCSymbolRefExpr::create(getSymbol(RHSGV), Ctx), Ctx);
+        int64_t Addend = (LHSOffset - RHSOffset).getSExtValue();
+        if (Addend != 0)
+          RelocExpr = MCBinaryExpr::createAdd(
+              RelocExpr, MCConstantExpr::create(Addend, Ctx), Ctx);
+        return RelocExpr;
+      }
+    }
+  }
+  // else fallthrough
+
   // The MC library also has a right-shift operator, but it isn't consistently
   // signed or unsigned between different targets.
   case Instruction::Add:
-  case Instruction::Sub:
   case Instruction::Mul:
   case Instruction::SDiv:
   case Instruction::SRem:
@@ -1964,7 +1954,7 @@ static void emitGlobalConstantDataSequential(const DataLayout &DL,
     uint64_t Bytes = DL.getTypeAllocSize(CDS->getType());
     // Don't emit a 1-byte object as a .fill.
     if (Bytes > 1)
-      return AP.OutStreamer->EmitFill(Bytes, Value);
+      return AP.OutStreamer->emitFill(Bytes, Value);
   }
 
   // If this can be emitted with .ascii/.asciz, emit it as such.
@@ -2003,7 +1993,7 @@ static void emitGlobalConstantArray(const DataLayout &DL,
 
   if (Value != -1) {
     uint64_t Bytes = DL.getTypeAllocSize(CA->getType());
-    AP.OutStreamer->EmitFill(Bytes, Value);
+    AP.OutStreamer->emitFill(Bytes, Value);
   }
   else {
     for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) {
@@ -2582,7 +2572,7 @@ isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
     // If we are the operands of one of the branches, this is not a fall
     // through. Note that targets with delay slots will usually bundle
     // terminators with the delay slot instruction.
-    for (ConstMIBundleOperands OP(&MI); OP.isValid(); ++OP) {
+    for (ConstMIBundleOperands OP(MI); OP.isValid(); ++OP) {
       if (OP->isJTI())
         return false;
       if (OP->isMBB() && OP->getMBB() == MBB)