[SCCP] Turn loads of null into undef instead of zero initialized values

[oota-llvm.git] / lib / MC / MCContext.cpp

diff --git a/lib/MC/MCContext.cpp b/lib/MC/MCContext.cpp
index 968fd26f326a230c8705ab3551b7ae2aeec4c84d..c601c56f3952d1406f24ab1954d989af18758466 100644 (file)
--- a/lib/MC/MCContext.cpp
+++ b/lib/MC/MCContext.cpp
@@ -10,6 +10,7 @@
 #include "llvm/MC/MCContext.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Twine.h"
+#include "llvm/MC/MCAssembler.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCDwarf.h"
 #include "llvm/MC/MCLabel.h"
@@ -19,7 +20,9 @@
 #include "llvm/MC/MCSectionELF.h"
 #include "llvm/MC/MCSectionMachO.h"
 #include "llvm/MC/MCStreamer.h"
-#include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCSymbolCOFF.h"
+#include "llvm/MC/MCSymbolELF.h"
+#include "llvm/MC/MCSymbolMachO.h"
 #include "llvm/Support/ELF.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileSystem.h"
@@ -54,7 +57,6 @@ MCContext::MCContext(const MCAsmInfo *mai, const MCRegisterInfo *mri,
 }
 
 MCContext::~MCContext() {
-
   if (AutoReset)
     reset();
 
@@ -70,6 +72,14 @@ MCContext::~MCContext() {
 //===----------------------------------------------------------------------===//
 
 void MCContext::reset() {
+  // Call the destructors so the fragments are freed
+  for (auto &I : ELFUniquingMap)
+    I.second->~MCSectionELF();
+  for (auto &I : COFFUniquingMap)
+    I.second->~MCSectionCOFF();
+  for (auto &I : MachOUniquingMap)
+    I.second->~MCSectionMachO();
+
   UsedNames.clear();
   Symbols.clear();
   Allocator.Reset();
@@ -106,13 +116,13 @@ MCSymbol *MCContext::getOrCreateSymbol(const Twine &Name) {
 
   MCSymbol *&Sym = Symbols[NameRef];
   if (!Sym)
-    Sym = CreateSymbol(NameRef, false);
+    Sym = createSymbol(NameRef, false, false);
 
   return Sym;
 }
 
-MCSymbol *MCContext::getOrCreateSectionSymbol(const MCSectionELF &Section) {
-  MCSymbol *&Sym = SectionSymbols[&Section];
+MCSymbolELF *MCContext::getOrCreateSectionSymbol(const MCSectionELF &Section) {
+  MCSymbolELF *&Sym = SectionSymbols[&Section];
   if (Sym)
     return Sym;
 
@@ -120,12 +130,12 @@ MCSymbol *MCContext::getOrCreateSectionSymbol(const MCSectionELF &Section) {
 
   MCSymbol *&OldSym = Symbols[Name];
   if (OldSym && OldSym->isUndefined()) {
-    Sym = OldSym;
-    return OldSym;
+    Sym = cast<MCSymbolELF>(OldSym);
+    return Sym;
   }
 
   auto NameIter = UsedNames.insert(std::make_pair(Name, true)).first;
-  Sym = new (*this) MCSymbol(&*NameIter, /*isTemporary*/ false);
+  Sym = new (&*NameIter, *this) MCSymbolELF(&*NameIter, /*isTemporary*/ false);
 
   if (!OldSym)
     OldSym = Sym;
@@ -149,14 +159,32 @@ MCSymbol *MCContext::getOrCreateLSDASymbol(StringRef FuncName) {
                            FuncName);
 }
 
-MCSymbol *MCContext::CreateSymbol(StringRef Name, bool AlwaysAddSuffix) {
-  // Determine whether this is an assembler temporary or normal label, if used.
-  bool IsTemporary = false;
-  if (AllowTemporaryLabels)
-    IsTemporary = Name.startswith(MAI->getPrivateGlobalPrefix());
+MCSymbol *MCContext::createSymbolImpl(const StringMapEntry<bool> *Name,
+                                      bool IsTemporary) {
+  if (MOFI) {
+    switch (MOFI->getObjectFileType()) {
+    case MCObjectFileInfo::IsCOFF:
+      return new (Name, *this) MCSymbolCOFF(Name, IsTemporary);
+    case MCObjectFileInfo::IsELF:
+      return new (Name, *this) MCSymbolELF(Name, IsTemporary);
+    case MCObjectFileInfo::IsMachO:
+      return new (Name, *this) MCSymbolMachO(Name, IsTemporary);
+    }
+  }
+  return new (Name, *this) MCSymbol(MCSymbol::SymbolKindUnset, Name,
+                                    IsTemporary);
+}
+
+MCSymbol *MCContext::createSymbol(StringRef Name, bool AlwaysAddSuffix,
+                                  bool CanBeUnnamed) {
+  if (CanBeUnnamed && !UseNamesOnTempLabels)
+    return createSymbolImpl(nullptr, true);
 
-  if (IsTemporary && AlwaysAddSuffix && !UseNamesOnTempLabels)
-    return new (*this) MCSymbol(nullptr, true);
+  // Determine whether this is an user writter assembler temporary or normal
+  // label, if used.
+  bool IsTemporary = CanBeUnnamed;
+  if (AllowTemporaryLabels && !IsTemporary)
+    IsTemporary = Name.startswith(MAI->getPrivateGlobalPrefix());
 
   SmallString<128> NewName = Name;
   bool AddSuffix = AlwaysAddSuffix;
@@ -170,8 +198,7 @@ MCSymbol *MCContext::CreateSymbol(StringRef Name, bool AlwaysAddSuffix) {
     if (NameEntry.second) {
       // Ok, we found a name. Have the MCSymbol object itself refer to the copy
       // of the string that is embedded in the UsedNames entry.
-      MCSymbol *Result = new (*this) MCSymbol(&*NameEntry.first, IsTemporary);
-      return Result;
+      return createSymbolImpl(&*NameEntry.first, IsTemporary);
     }
     assert(IsTemporary && "Cannot rename non-temporary symbols");
     AddSuffix = true;
@@ -179,20 +206,21 @@ MCSymbol *MCContext::CreateSymbol(StringRef Name, bool AlwaysAddSuffix) {
   llvm_unreachable("Infinite loop");
 }
 
-MCSymbol *MCContext::createTempSymbol(const Twine &Name, bool AlwaysAddSuffix) {
+MCSymbol *MCContext::createTempSymbol(const Twine &Name, bool AlwaysAddSuffix,
+                                      bool CanBeUnnamed) {
   SmallString<128> NameSV;
   raw_svector_ostream(NameSV) << MAI->getPrivateGlobalPrefix() << Name;
-  return CreateSymbol(NameSV, AlwaysAddSuffix);
+  return createSymbol(NameSV, AlwaysAddSuffix, CanBeUnnamed);
 }
 
 MCSymbol *MCContext::createLinkerPrivateTempSymbol() {
   SmallString<128> NameSV;
   raw_svector_ostream(NameSV) << MAI->getLinkerPrivateGlobalPrefix() << "tmp";
-  return CreateSymbol(NameSV, true);
+  return createSymbol(NameSV, true, false);
 }
 
-MCSymbol *MCContext::createTempSymbol() {
-  return createTempSymbol("tmp", true);
+MCSymbol *MCContext::createTempSymbol(bool CanBeUnnamed) {
+  return createTempSymbol("tmp", true, CanBeUnnamed);
 }
 
 unsigned MCContext::NextInstance(unsigned LocalLabelVal) {
@@ -213,7 +241,7 @@ MCSymbol *MCContext::getOrCreateDirectionalLocalSymbol(unsigned LocalLabelVal,
                                                        unsigned Instance) {
   MCSymbol *&Sym = LocalSymbols[std::make_pair(LocalLabelVal, Instance)];
   if (!Sym)
-    Sym = createTempSymbol();
+    Sym = createTempSymbol(false);
   return Sym;
 }
 
@@ -287,7 +315,7 @@ void MCContext::renameELFSection(MCSectionELF *Section, StringRef Name) {
 
 MCSectionELF *MCContext::createELFRelSection(StringRef Name, unsigned Type,
                                              unsigned Flags, unsigned EntrySize,
-                                             const MCSymbol *Group,
+                                             const MCSymbolELF *Group,
                                              const MCSectionELF *Associated) {
   StringMap<bool>::iterator I;
   bool Inserted;
@@ -302,9 +330,9 @@ MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
                                        unsigned Flags, unsigned EntrySize,
                                        StringRef Group, unsigned UniqueID,
                                        const char *BeginSymName) {
-  MCSymbol *GroupSym = nullptr;
+  MCSymbolELF *GroupSym = nullptr;
   if (!Group.empty())
-    GroupSym = getOrCreateSymbol(Group);
+    GroupSym = cast<MCSymbolELF>(getOrCreateSymbol(Group));
 
   return getELFSection(Section, Type, Flags, EntrySize, GroupSym, UniqueID,
                        BeginSymName, nullptr);
@@ -312,7 +340,7 @@ MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
 
 MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
                                        unsigned Flags, unsigned EntrySize,
-                                       const MCSymbol *GroupSym,
+                                       const MCSymbolELF *GroupSym,
                                        unsigned UniqueID,
                                        const char *BeginSymName,
                                        const MCSectionELF *Associated) {
@@ -345,7 +373,7 @@ MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
   return Result;
 }
 
-MCSectionELF *MCContext::createELFGroupSection(const MCSymbol *Group) {
+MCSectionELF *MCContext::createELFGroupSection(const MCSymbolELF *Group) {
   MCSectionELF *Result = new (*this)
       MCSectionELF(".group", ELF::SHT_GROUP, 0, SectionKind::getReadOnly(), 4,
                    Group, ~0, nullptr, nullptr);
@@ -439,13 +467,8 @@ bool MCContext::isValidDwarfFileNumber(unsigned FileNumber, unsigned CUID) {
 /// Remove empty sections from SectionStartEndSyms, to avoid generating
 /// useless debug info for them.
 void MCContext::finalizeDwarfSections(MCStreamer &MCOS) {
-  std::vector<MCSection *> Keep;
-  for (MCSection *Sec : SectionsForRanges) {
-    if (MCOS.mayHaveInstructions(*Sec))
-      Keep.push_back(Sec);
-  }
-  SectionsForRanges.clear();
-  SectionsForRanges.insert(Keep.begin(), Keep.end());
+  SectionsForRanges.remove_if(
+      [&](MCSection *Sec) { return !MCOS.mayHaveInstructions(*Sec); });
 }
 
 void MCContext::reportFatalError(SMLoc Loc, const Twine &Msg) const {