Add back r201608, r201622, r201624 and r201625

r201608 made llvm corretly handle private globals with MachO. r201622 fixed
a bug in it and r201624 and r201625 were changes for using private linkage,
assuming that llvm would do the right thing.

They all got reverted because r201608 introduced a crash in LTO. This patch
includes a fix for that. The issue was that TargetLoweringObjectFile now has
to be initialized before we can mangle names of private globals. This is
trivially true during the normal codegen pipeline (the asm printer does it),
but LTO has to do it manually.

llvm-svn: 201700
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 63b4bb4..6c4cddc 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -311,8 +311,13 @@
   llvm_unreachable("Unknown linkage type!");
 }
 
+void AsmPrinter::getNameWithPrefix(SmallVectorImpl<char> &Name,
+                                   const GlobalValue *GV) const {
+  TM.getTargetLowering()->getNameWithPrefix(Name, GV, *Mang);
+}
+
 MCSymbol *AsmPrinter::getSymbol(const GlobalValue *GV) const {
-  return getObjFileLowering().getSymbol(GV, *Mang);
+  return TM.getTargetLowering()->getSymbol(GV, *Mang);
 }
 
 /// EmitGlobalVariable - Emit the specified global variable to the .s file.
@@ -1369,7 +1374,7 @@
   for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
     const GlobalValue *GV =
       dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
-    if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, *Mang))
+    if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, *Mang, TM))
       OutStreamer.EmitSymbolAttribute(getSymbol(GV), MCSA_NoDeadStrip);
   }
 }
@@ -1574,7 +1579,8 @@
   }
 
   if (const MCExpr *RelocExpr =
-          AP.getObjFileLowering().getExecutableRelativeSymbol(CE, *AP.Mang))
+          AP.getObjFileLowering().getExecutableRelativeSymbol(CE, *AP.Mang,
+                                                              AP.TM))
     return RelocExpr;
 
   switch (CE->getOpcode()) {
@@ -2103,7 +2109,8 @@
 
 MCSymbol *AsmPrinter::getSymbolWithGlobalValueBase(const GlobalValue *GV,
                                                    StringRef Suffix) const {
-  return getObjFileLowering().getSymbolWithGlobalValueBase(GV, Suffix, *Mang);
+  return getObjFileLowering().getSymbolWithGlobalValueBase(GV, Suffix, *Mang,
+                                                           TM);
 }
 
 /// GetExternalSymbolSymbol - Return the MCSymbol for the specified
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp
index 94198c4..5f23e12 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp
@@ -143,7 +143,7 @@
     const TargetLoweringObjectFile &TLOF = getObjFileLowering();
 
     const MCExpr *Exp =
-        TLOF.getTTypeGlobalReference(GV, Encoding, *Mang, MMI, OutStreamer);
+        TLOF.getTTypeGlobalReference(GV, Encoding, *Mang, TM, MMI, OutStreamer);
     OutStreamer.EmitValue(Exp, GetSizeOfEncodedValue(Encoding));
   } else
     OutStreamer.EmitIntValue(0, GetSizeOfEncodedValue(Encoding));
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
index ed51f50..30312ac 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
@@ -119,7 +119,8 @@
   if (!shouldEmitPersonality)
     return;
 
-  const MCSymbol *Sym = TLOF.getCFIPersonalitySymbol(Per, *Asm->Mang, MMI);
+  const MCSymbol *Sym =
+      TLOF.getCFIPersonalitySymbol(Per, *Asm->Mang, Asm->TM, MMI);
   Asm->OutStreamer.EmitCFIPersonality(Sym, PerEncoding);
 
   Asm->OutStreamer.EmitDebugLabel
diff --git a/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp b/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp
index eda444b..17d8bff 100644
--- a/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp
@@ -101,7 +101,8 @@
   if (shouldEmitPersonality) {
     const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
     const Function *Per = MMI->getPersonalities()[MMI->getPersonalityIndex()];
-    const MCSymbol *Sym = TLOF.getCFIPersonalitySymbol(Per, *Asm->Mang, MMI);
+    const MCSymbol *Sym =
+        TLOF.getCFIPersonalitySymbol(Per, *Asm->Mang, Asm->TM, MMI);
 
     Asm->OutStreamer.PushSection();
     Asm->OutStreamer.EmitWin64EHHandlerData();
diff --git a/llvm/lib/CodeGen/TargetLoweringBase.cpp b/llvm/lib/CodeGen/TargetLoweringBase.cpp
index bdcb721..d3c42be 100644
--- a/llvm/lib/CodeGen/TargetLoweringBase.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringBase.cpp
@@ -24,7 +24,9 @@
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/Mangler.h"
 #include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -1426,3 +1428,30 @@
 
   return true;
 }
+
+void TargetLoweringBase::getNameWithPrefix(SmallVectorImpl<char> &Name,
+                                           const GlobalValue *GV,
+                                           Mangler &Mang,
+                                           bool MayAlwaysUsePrivate) const {
+  if (MayAlwaysUsePrivate || !GV->hasPrivateLinkage()) {
+    // Simple case: If GV is not private, it is not important to find out if
+    // private labels are legal in this case or not.
+    Mang.getNameWithPrefix(Name, GV, false);
+    return;
+  }
+  SectionKind GVKind =
+    TargetLoweringObjectFile::getKindForGlobal(GV, getTargetMachine());
+  const TargetLoweringObjectFile &TLOF = getObjFileLowering();
+  const MCSection *TheSection =
+    TLOF.SectionForGlobal(GV, GVKind, Mang, getTargetMachine());
+  bool CannotUsePrivateLabel = TLOF.isSectionAtomizableBySymbols(*TheSection);
+  Mang.getNameWithPrefix(Name, GV, CannotUsePrivateLabel);
+}
+
+MCSymbol *TargetLoweringBase::getSymbol(const GlobalValue *GV,
+                                        Mangler &Mang) const {
+  SmallString<60> NameStr;
+  getNameWithPrefix(NameStr, GV, Mang);
+  const TargetLoweringObjectFile &TLOF = getObjFileLowering();
+  return TLOF.getContext().GetOrCreateSymbol(NameStr.str());
+}
diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 127b2aa..bd54a87 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -36,6 +36,7 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetLowering.h"
 using namespace llvm;
 using namespace dwarf;
 
@@ -43,19 +44,18 @@
 //                                  ELF
 //===----------------------------------------------------------------------===//
 
-MCSymbol *
-TargetLoweringObjectFileELF::getCFIPersonalitySymbol(const GlobalValue *GV,
-                                                     Mangler &Mang,
-                                                MachineModuleInfo *MMI) const {
+MCSymbol *TargetLoweringObjectFileELF::getCFIPersonalitySymbol(
+    const GlobalValue *GV, Mangler &Mang, const TargetMachine &TM,
+    MachineModuleInfo *MMI) const {
   unsigned Encoding = getPersonalityEncoding();
   switch (Encoding & 0x70) {
   default:
     report_fatal_error("We do not support this DWARF encoding yet!");
   case dwarf::DW_EH_PE_absptr:
-    return getSymbol(GV, Mang);
+    return TM.getTargetLowering()->getSymbol(GV, Mang);
   case dwarf::DW_EH_PE_pcrel: {
     return getContext().GetOrCreateSymbol(StringRef("DW.ref.") +
-                                          getSymbol(GV, Mang)->getName());
+                        TM.getTargetLowering()->getSymbol(GV, Mang)->getName());
   }
   }
 }
@@ -89,18 +89,19 @@
 
 const MCExpr *TargetLoweringObjectFileELF::getTTypeGlobalReference(
     const GlobalValue *GV, unsigned Encoding, Mangler &Mang,
-    MachineModuleInfo *MMI, MCStreamer &Streamer) const {
+    const TargetMachine &TM, MachineModuleInfo *MMI,
+    MCStreamer &Streamer) const {
 
   if (Encoding & dwarf::DW_EH_PE_indirect) {
     MachineModuleInfoELF &ELFMMI = MMI->getObjFileInfo<MachineModuleInfoELF>();
 
-    MCSymbol *SSym = getSymbolWithGlobalValueBase(GV, ".DW.stub", Mang);
+    MCSymbol *SSym = getSymbolWithGlobalValueBase(GV, ".DW.stub", Mang, TM);
 
     // Add information about the stub reference to ELFMMI so that the stub
     // gets emitted by the asmprinter.
     MachineModuleInfoImpl::StubValueTy &StubSym = ELFMMI.getGVStubEntry(SSym);
     if (StubSym.getPointer() == 0) {
-      MCSymbol *Sym = getSymbol(GV, Mang);
+      MCSymbol *Sym = TM.getTargetLowering()->getSymbol(GV, Mang);
       StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
     }
 
@@ -109,8 +110,8 @@
                         Encoding & ~dwarf::DW_EH_PE_indirect, Streamer);
   }
 
-  return TargetLoweringObjectFile::getTTypeGlobalReference(GV, Encoding, Mang,
-                                                           MMI, Streamer);
+  return TargetLoweringObjectFile::
+    getTTypeGlobalReference(GV, Encoding, Mang, TM, MMI, Streamer);
 }
 
 static SectionKind
@@ -195,10 +196,9 @@
   return Flags;
 }
 
-
-const MCSection *TargetLoweringObjectFileELF::
-getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
-                         Mangler &Mang, const TargetMachine &TM) const {
+const MCSection *TargetLoweringObjectFileELF::getExplicitSectionGlobal(
+    const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
+    const TargetMachine &TM) const {
   StringRef SectionName = GV->getSection();
 
   // Infer section flags from the section name if we can.
@@ -248,12 +248,12 @@
     Prefix = getSectionPrefixForGlobal(Kind);
 
     SmallString<128> Name(Prefix, Prefix+strlen(Prefix));
-    MCSymbol *Sym = getSymbol(GV, Mang);
-    Name.append(Sym->getName().begin(), Sym->getName().end());
+    TM.getTargetLowering()->getNameWithPrefix(Name, GV, Mang, true);
+
     StringRef Group = "";
     unsigned Flags = getELFSectionFlags(Kind);
     if (GV->isWeakForLinker()) {
-      Group = Sym->getName();
+      Group = Name.substr(strlen(Prefix));
       Flags |= ELF::SHF_GROUP;
     }
 
@@ -487,9 +487,9 @@
   Streamer.AddBlankLine();
 }
 
-const MCSection *TargetLoweringObjectFileMachO::
-getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
-                         Mangler &Mang, const TargetMachine &TM) const {
+const MCSection *TargetLoweringObjectFileMachO::getExplicitSectionGlobal(
+    const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
+    const TargetMachine &TM) const {
   // Parse the section specifier and create it if valid.
   StringRef Segment, Section;
   unsigned TAA = 0, StubSize = 0;
@@ -526,6 +526,41 @@
   return S;
 }
 
+bool TargetLoweringObjectFileMachO::isSectionAtomizableBySymbols(
+    const MCSection &Section) const {
+    const MCSectionMachO &SMO = static_cast<const MCSectionMachO&>(Section);
+
+    // Sections holding 1 byte strings are atomized based on the data
+    // they contain.
+    // Sections holding 2 byte strings require symbols in order to be
+    // atomized.
+    // There is no dedicated section for 4 byte strings.
+    if (SMO.getKind().isMergeable1ByteCString())
+      return false;
+
+    if (SMO.getSegmentName() == "__DATA" &&
+        SMO.getSectionName() == "__cfstring")
+      return false;
+
+    switch (SMO.getType()) {
+    default:
+      return true;
+
+      // These sections are atomized at the element boundaries without using
+      // symbols.
+    case MCSectionMachO::S_4BYTE_LITERALS:
+    case MCSectionMachO::S_8BYTE_LITERALS:
+    case MCSectionMachO::S_16BYTE_LITERALS:
+    case MCSectionMachO::S_LITERAL_POINTERS:
+    case MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS:
+    case MCSectionMachO::S_LAZY_SYMBOL_POINTERS:
+    case MCSectionMachO::S_MOD_INIT_FUNC_POINTERS:
+    case MCSectionMachO::S_MOD_TERM_FUNC_POINTERS:
+    case MCSectionMachO::S_INTERPOSING:
+      return false;
+    }
+}
+
 const MCSection *TargetLoweringObjectFileMachO::
 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
                        Mangler &Mang, const TargetMachine &TM) const {
@@ -606,21 +641,17 @@
   return ReadOnlySection;  // .const
 }
 
-/// shouldEmitUsedDirectiveFor - This hook allows targets to selectively decide
-/// not to emit the UsedDirective for some symbols in llvm.used.
+/// This hook allows targets to selectively decide not to emit the UsedDirective
+/// for some symbols in llvm.used.
 // FIXME: REMOVE this (rdar://7071300)
-bool TargetLoweringObjectFileMachO::
-shouldEmitUsedDirectiveFor(const GlobalValue *GV, Mangler &Mang) const {
-  /// On Darwin, internally linked data beginning with "L" or "l" does not have
-  /// the directive emitted (this occurs in ObjC metadata).
-  if (!GV) return false;
-
+bool TargetLoweringObjectFileMachO::shouldEmitUsedDirectiveFor(
+    const GlobalValue *GV, Mangler &Mang, TargetMachine &TM) const {
   // Check whether the mangled name has the "Private" or "LinkerPrivate" prefix.
   if (GV->hasLocalLinkage() && !isa<Function>(GV)) {
     // FIXME: ObjC metadata is currently emitted as internal symbols that have
     // \1L and \0l prefixes on them.  Fix them to be Private/LinkerPrivate and
     // this horrible hack can go away.
-    MCSymbol *Sym = getSymbol(GV, Mang);
+    MCSymbol *Sym = TM.getTargetLowering()->getSymbol(GV, Mang);
     if (Sym->getName()[0] == 'L' || Sym->getName()[0] == 'l')
       return false;
   }
@@ -630,14 +661,16 @@
 
 const MCExpr *TargetLoweringObjectFileMachO::getTTypeGlobalReference(
     const GlobalValue *GV, unsigned Encoding, Mangler &Mang,
-    MachineModuleInfo *MMI, MCStreamer &Streamer) const {
+    const TargetMachine &TM, MachineModuleInfo *MMI,
+    MCStreamer &Streamer) const {
   // The mach-o version of this method defaults to returning a stub reference.
 
   if (Encoding & DW_EH_PE_indirect) {
     MachineModuleInfoMachO &MachOMMI =
       MMI->getObjFileInfo<MachineModuleInfoMachO>();
 
-    MCSymbol *SSym = getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr", Mang);
+    MCSymbol *SSym =
+        getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr", Mang, TM);
 
     // Add information about the stub reference to MachOMMI so that the stub
     // gets emitted by the asmprinter.
@@ -645,7 +678,7 @@
       GV->hasHiddenVisibility() ? MachOMMI.getHiddenGVStubEntry(SSym) :
                                   MachOMMI.getGVStubEntry(SSym);
     if (StubSym.getPointer() == 0) {
-      MCSymbol *Sym = getSymbol(GV, Mang);
+      MCSymbol *Sym = TM.getTargetLowering()->getSymbol(GV, Mang);
       StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
     }
 
@@ -654,24 +687,24 @@
                         Encoding & ~dwarf::DW_EH_PE_indirect, Streamer);
   }
 
-  return TargetLoweringObjectFile::
-    getTTypeGlobalReference(GV, Encoding, Mang, MMI, Streamer);
+  return TargetLoweringObjectFile::getTTypeGlobalReference(GV, Encoding, Mang,
+                                                           TM, MMI, Streamer);
 }
 
-MCSymbol *TargetLoweringObjectFileMachO::
-getCFIPersonalitySymbol(const GlobalValue *GV, Mangler &Mang,
-                        MachineModuleInfo *MMI) const {
+MCSymbol *TargetLoweringObjectFileMachO::getCFIPersonalitySymbol(
+    const GlobalValue *GV, Mangler &Mang, const TargetMachine &TM,
+    MachineModuleInfo *MMI) const {
   // The mach-o version of this method defaults to returning a stub reference.
   MachineModuleInfoMachO &MachOMMI =
     MMI->getObjFileInfo<MachineModuleInfoMachO>();
 
-  MCSymbol *SSym = getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr", Mang);
+  MCSymbol *SSym = getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr", Mang, TM);
 
   // Add information about the stub reference to MachOMMI so that the stub
   // gets emitted by the asmprinter.
   MachineModuleInfoImpl::StubValueTy &StubSym = MachOMMI.getGVStubEntry(SSym);
   if (StubSym.getPointer() == 0) {
-    MCSymbol *Sym = getSymbol(GV, Mang);
+    MCSymbol *Sym = TM.getTargetLowering()->getSymbol(GV, Mang);
     StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
   }
 
@@ -717,9 +750,9 @@
   return Flags;
 }
 
-const MCSection *TargetLoweringObjectFileCOFF::
-getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
-                         Mangler &Mang, const TargetMachine &TM) const {
+const MCSection *TargetLoweringObjectFileCOFF::getExplicitSectionGlobal(
+    const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
+    const TargetMachine &TM) const {
   int Selection = 0;
   unsigned Characteristics = getCOFFSectionFlags(Kind);
   StringRef Name = GV->getSection();
@@ -727,7 +760,7 @@
   if (GV->isWeakForLinker()) {
     Selection = COFF::IMAGE_COMDAT_SELECT_ANY;
     Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
-    MCSymbol *Sym = getSymbol(GV, Mang);
+    MCSymbol *Sym = TM.getTargetLowering()->getSymbol(GV, Mang);
     COMDATSymName = Sym->getName();
   }
   return getContext().getCOFFSection(Name,
@@ -761,7 +794,7 @@
     unsigned Characteristics = getCOFFSectionFlags(Kind);
 
     Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
-    MCSymbol *Sym = getSymbol(GV, Mang);
+    MCSymbol *Sym = TM.getTargetLowering()->getSymbol(GV, Mang);
     return getContext().getCOFFSection(Name, Characteristics,
                                        Kind, Sym->getName(),
                                        COFF::IMAGE_COMDAT_SELECT_ANY);