Introduce new linkage types linkonce_odr, weak_odr, common_odr

and extern_weak_odr.  These are the same as the non-odr versions,
except that they indicate that the global will only be overridden
by an *equivalent* global.  In C, a function with weak linkage can
be overridden by a function which behaves completely differently.
This means that IP passes have to skip weak functions, since any
deductions made from the function definition might be wrong, since
the definition could be replaced by something completely different
at link time.   This is not allowed in C++, thanks to the ODR
(One-Definition-Rule): if a function is replaced by another at
link-time, then the new function must be the same as the original
function.  If a language knows that a function or other global can
only be overridden by an equivalent global, it can give it the
weak_odr linkage type, and the optimizers will understand that it
is alright to make deductions based on the function body.  The
code generators on the other hand map weak and weak_odr linkage
to the same thing.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66339 91177308-0d34-0410-b5e6-96231b3b80d8

18 files changed, 133 insertions, 77 deletions

diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index 41852fa594..cc38efb9cc 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -854,7 +854,7 @@ static bool GVIsIndirectSymbol(GlobalValue *GV, Reloc::Model RelocM) {
   bool isDecl = GV->isDeclaration() && !GV->hasNotBeenReadFromBitcode();
   if (GV->hasHiddenVisibility() && (!isDecl && !GV->hasCommonLinkage()))
     return false;
-  return RelocM != Reloc::Static && (isDecl || GV->mayBeOverridden());
+  return RelocM != Reloc::Static && (isDecl || GV->isWeakForLinker());
 }
 
 SDValue ARMTargetLowering::LowerGlobalAddressDarwin(SDValue Op,
diff --git a/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp b/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp
index 969b8face4..ae968e7b09 100644
--- a/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp
+++ b/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp
@@ -208,8 +208,10 @@ bool ARMAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
     SwitchToTextSection("\t.text", F);
     O << "\t.globl\t" << CurrentFnName << "\n";
     break;
-  case Function::WeakLinkage:
-  case Function::LinkOnceLinkage:
+  case Function::WeakAnyLinkage:
+  case Function::WeakODRLinkage:
+  case Function::LinkOnceAnyLinkage:
+  case Function::LinkOnceODRLinkage:
     if (Subtarget->isTargetDarwin()) {
       SwitchToTextSection(
                 ".section __TEXT,__textcoal_nt,coalesced,pure_instructions", F);
@@ -853,7 +855,7 @@ void ARMAsmPrinter::printModuleLevelGV(const GlobalVariable* GVar) {
       }
     }
 
-    if (GVar->hasLocalLinkage() || GVar->mayBeOverridden()) {
+    if (GVar->hasLocalLinkage() || GVar->isWeakForLinker()) {
       if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
 
       if (isDarwin) {
@@ -899,9 +901,12 @@ void ARMAsmPrinter::printModuleLevelGV(const GlobalVariable* GVar) {
 
   SwitchToSection(TAI->SectionForGlobal(GVar));
   switch (GVar->getLinkage()) {
-   case GlobalValue::CommonLinkage:
-   case GlobalValue::LinkOnceLinkage:
-   case GlobalValue::WeakLinkage:
+   case GlobalValue::CommonAnyLinkage:
+   case GlobalValue::CommonODRLinkage:
+   case GlobalValue::LinkOnceAnyLinkage:
+   case GlobalValue::LinkOnceODRLinkage:
+   case GlobalValue::WeakAnyLinkage:
+   case GlobalValue::WeakODRLinkage:
     if (isDarwin) {
       O << "\t.globl " << name << "\n"
         << "\t.weak_definition " << name << "\n";
diff --git a/lib/Target/Alpha/AsmPrinter/AlphaAsmPrinter.cpp b/lib/Target/Alpha/AsmPrinter/AlphaAsmPrinter.cpp
index 536e5920f3..5238b79d9d 100644
--- a/lib/Target/Alpha/AsmPrinter/AlphaAsmPrinter.cpp
+++ b/lib/Target/Alpha/AsmPrinter/AlphaAsmPrinter.cpp
@@ -163,8 +163,10 @@ bool AlphaAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
    case Function::ExternalLinkage:
      O << "\t.globl " << CurrentFnName << "\n";
      break;
-  case Function::WeakLinkage:
-  case Function::LinkOnceLinkage:
+  case Function::WeakAnyLinkage:
+  case Function::WeakODRLinkage:
+  case Function::LinkOnceAnyLinkage:
+  case Function::LinkOnceODRLinkage:
     O << TAI->getWeakRefDirective() << CurrentFnName << "\n";
     break;
   }
@@ -231,9 +233,12 @@ void AlphaAsmPrinter::printModuleLevelGV(const GlobalVariable* GVar) {
 
   // 2: Kind
   switch (GVar->getLinkage()) {
-   case GlobalValue::LinkOnceLinkage:
-   case GlobalValue::WeakLinkage:
-   case GlobalValue::CommonLinkage:
+   case GlobalValue::LinkOnceAnyLinkage:
+   case GlobalValue::LinkOnceODRLinkage:
+   case GlobalValue::WeakAnyLinkage:
+   case GlobalValue::WeakODRLinkage:
+   case GlobalValue::CommonAnyLinkage:
+   case GlobalValue::CommonODRLinkage:
     O << TAI->getWeakRefDirective() << name << '\n';
     break;
    case GlobalValue::AppendingLinkage:
diff --git a/lib/Target/CellSPU/AsmPrinter/SPUAsmPrinter.cpp b/lib/Target/CellSPU/AsmPrinter/SPUAsmPrinter.cpp
index f784d70f44..7731a9023a 100644
--- a/lib/Target/CellSPU/AsmPrinter/SPUAsmPrinter.cpp
+++ b/lib/Target/CellSPU/AsmPrinter/SPUAsmPrinter.cpp
@@ -445,8 +445,10 @@ LinuxAsmPrinter::runOnMachineFunction(MachineFunction &MF)
     O << "\t.global\t" << CurrentFnName << "\n"
       << "\t.type\t" << CurrentFnName << ", @function\n";
     break;
-  case Function::WeakLinkage:
-  case Function::LinkOnceLinkage:
+  case Function::WeakAnyLinkage:
+  case Function::WeakODRLinkage:
+  case Function::LinkOnceAnyLinkage:
+  case Function::LinkOnceODRLinkage:
     O << "\t.global\t" << CurrentFnName << "\n";
     O << "\t.weak_definition\t" << CurrentFnName << "\n";
     break;
@@ -534,7 +536,7 @@ void LinuxAsmPrinter::printModuleLevelGV(const GlobalVariable* GVar) {
   if (C->isNullValue() && /* FIXME: Verify correct */
       !GVar->hasSection() &&
       (GVar->hasLocalLinkage() || GVar->hasExternalLinkage() ||
-       GVar->mayBeOverridden())) {
+       GVar->isWeakForLinker())) {
       if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
 
       if (GVar->hasExternalLinkage()) {
@@ -555,9 +557,12 @@ void LinuxAsmPrinter::printModuleLevelGV(const GlobalVariable* GVar) {
 
   switch (GVar->getLinkage()) {
     // Should never be seen for the CellSPU platform...
-   case GlobalValue::LinkOnceLinkage:
-   case GlobalValue::WeakLinkage:
-   case GlobalValue::CommonLinkage:
+   case GlobalValue::LinkOnceAnyLinkage:
+   case GlobalValue::LinkOnceODRLinkage:
+   case GlobalValue::WeakAnyLinkage:
+   case GlobalValue::WeakODRLinkage:
+   case GlobalValue::CommonAnyLinkage:
+   case GlobalValue::CommonODRLinkage:
     O << "\t.global " << name << '\n'
       << "\t.type " << name << ", @object\n"
       << "\t.weak " << name << '\n';
diff --git a/lib/Target/CppBackend/CPPBackend.cpp b/lib/Target/CppBackend/CPPBackend.cpp
index dbe4f2d2d3..48cf4959e0 100644
--- a/lib/Target/CppBackend/CPPBackend.cpp
+++ b/lib/Target/CppBackend/CPPBackend.cpp
@@ -294,10 +294,14 @@ namespace {
       Out << "GlobalValue::InternalLinkage"; break;
     case GlobalValue::PrivateLinkage:
       Out << "GlobalValue::PrivateLinkage"; break;
-    case GlobalValue::LinkOnceLinkage:
-      Out << "GlobalValue::LinkOnceLinkage "; break;
-    case GlobalValue::WeakLinkage:
-      Out << "GlobalValue::WeakLinkage"; break;
+    case GlobalValue::LinkOnceAnyLinkage:
+      Out << "GlobalValue::LinkOnceAnyLinkage "; break;
+    case GlobalValue::LinkOnceODRLinkage:
+      Out << "GlobalValue::LinkOnceODRLinkage "; break;
+    case GlobalValue::WeakAnyLinkage:
+      Out << "GlobalValue::WeakAnyLinkage"; break;
+    case GlobalValue::WeakODRLinkage:
+      Out << "GlobalValue::WeakODRLinkage"; break;
     case GlobalValue::AppendingLinkage:
       Out << "GlobalValue::AppendingLinkage"; break;
     case GlobalValue::ExternalLinkage:
@@ -306,12 +310,16 @@ namespace {
       Out << "GlobalValue::DLLImportLinkage"; break;
     case GlobalValue::DLLExportLinkage:
       Out << "GlobalValue::DLLExportLinkage"; break;
-    case GlobalValue::ExternalWeakLinkage:
-      Out << "GlobalValue::ExternalWeakLinkage"; break;
+    case GlobalValue::ExternalWeakAnyLinkage:
+      Out << "GlobalValue::ExternalWeakAnyLinkage"; break;
+    case GlobalValue::ExternalWeakODRLinkage:
+      Out << "GlobalValue::ExternalWeakODRLinkage"; break;
     case GlobalValue::GhostLinkage:
       Out << "GlobalValue::GhostLinkage"; break;
-    case GlobalValue::CommonLinkage:
-      Out << "GlobalValue::CommonLinkage"; break;
+    case GlobalValue::CommonAnyLinkage:
+      Out << "GlobalValue::CommonAnyLinkage"; break;
+    case GlobalValue::CommonODRLinkage:
+      Out << "GlobalValue::CommonODRLinkage"; break;
     }
   }
 
diff --git a/lib/Target/DarwinTargetAsmInfo.cpp b/lib/Target/DarwinTargetAsmInfo.cpp
index cc05c09c51..927fdd2953 100644
--- a/lib/Target/DarwinTargetAsmInfo.cpp
+++ b/lib/Target/DarwinTargetAsmInfo.cpp
@@ -75,7 +75,7 @@ DarwinTargetAsmInfo::emitUsedDirectiveFor(const GlobalValue* GV,
 const Section*
 DarwinTargetAsmInfo::SelectSectionForGlobal(const GlobalValue *GV) const {
   SectionKind::Kind Kind = SectionKindForGlobal(GV);
-  bool isWeak = GV->mayBeOverridden();
+  bool isWeak = GV->isWeakForLinker();
   bool isNonStatic = TM.getRelocationModel() != Reloc::Static;
 
   switch (Kind) {
diff --git a/lib/Target/ELFTargetAsmInfo.cpp b/lib/Target/ELFTargetAsmInfo.cpp
index 624b95c7b6..3a2a00c658 100644
--- a/lib/Target/ELFTargetAsmInfo.cpp
+++ b/lib/Target/ELFTargetAsmInfo.cpp
@@ -49,14 +49,16 @@ ELFTargetAsmInfo::SelectSectionForGlobal(const GlobalValue *GV) const {
      case Function::DLLExportLinkage:
      case Function::ExternalLinkage:
       return TextSection;
-     case Function::WeakLinkage:
-     case Function::LinkOnceLinkage:
+     case Function::WeakAnyLinkage:
+     case Function::WeakODRLinkage:
+     case Function::LinkOnceAnyLinkage:
+     case Function::LinkOnceODRLinkage:
       std::string Name = UniqueSectionForGlobal(GV, Kind);
       unsigned Flags = SectionFlagsForGlobal(GV, Name.c_str());
       return getNamedSection(Name.c_str(), Flags);
     }
   } else if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) {
-    if (GVar->mayBeOverridden()) {
+    if (GVar->isWeakForLinker()) {
       std::string Name = UniqueSectionForGlobal(GVar, Kind);
       unsigned Flags = SectionFlagsForGlobal(GVar, Name.c_str());
       return getNamedSection(Name.c_str(), Flags);
diff --git a/lib/Target/IA64/IA64AsmPrinter.cpp b/lib/Target/IA64/IA64AsmPrinter.cpp
index 00474309d5..d8ec2108c9 100644
--- a/lib/Target/IA64/IA64AsmPrinter.cpp
+++ b/lib/Target/IA64/IA64AsmPrinter.cpp
@@ -278,7 +278,7 @@ void IA64AsmPrinter::printModuleLevelGV(const GlobalVariable* GVar) {
 
   if (C->isNullValue() && !GVar->hasSection()) {
     if (!GVar->isThreadLocal() &&
-        (GVar->hasLocalLinkage() || GVar->mayBeOverridden())) {
+        (GVar->hasLocalLinkage() || GVar->isWeakForLinker())) {
       if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
 
       if (GVar->hasLocalLinkage()) {
@@ -296,9 +296,12 @@ void IA64AsmPrinter::printModuleLevelGV(const GlobalVariable* GVar) {
   }
 
   switch (GVar->getLinkage()) {
-   case GlobalValue::LinkOnceLinkage:
-   case GlobalValue::CommonLinkage:
-   case GlobalValue::WeakLinkage:
+   case GlobalValue::LinkOnceAnyLinkage:
+   case GlobalValue::LinkOnceODRLinkage:
+   case GlobalValue::CommonAnyLinkage:
+   case GlobalValue::CommonODRLinkage:
+   case GlobalValue::WeakAnyLinkage:
+   case GlobalValue::WeakODRLinkage:
     // Nonnull linkonce -> weak
     O << "\t.weak " << name << '\n';
     break;
diff --git a/lib/Target/Mips/MipsAsmPrinter.cpp b/lib/Target/Mips/MipsAsmPrinter.cpp
index 732c5d796c..a22d7d6ebc 100644
--- a/lib/Target/Mips/MipsAsmPrinter.cpp
+++ b/lib/Target/Mips/MipsAsmPrinter.cpp
@@ -504,7 +504,7 @@ printModuleLevelGV(const GlobalVariable* GVar) {
 
   if (C->isNullValue() && !GVar->hasSection()) {
     if (!GVar->isThreadLocal() &&
-        (GVar->hasLocalLinkage() || GVar->mayBeOverridden())) {
+        (GVar->hasLocalLinkage() || GVar->isWeakForLinker())) {
       if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
 
       if (GVar->hasLocalLinkage())
@@ -519,9 +519,12 @@ printModuleLevelGV(const GlobalVariable* GVar) {
     }
   }
   switch (GVar->getLinkage()) {
-   case GlobalValue::LinkOnceLinkage:
-   case GlobalValue::CommonLinkage:
-   case GlobalValue::WeakLinkage:
+   case GlobalValue::LinkOnceAnyLinkage:
+   case GlobalValue::LinkOnceODRLinkage:
+   case GlobalValue::CommonAnyLinkage:
+   case GlobalValue::CommonODRLinkage:
+   case GlobalValue::WeakAnyLinkage:
+   case GlobalValue::WeakODRLinkage:
     // FIXME: Verify correct for weak.
     // Nonnull linkonce -> weak
     O << "\t.weak " << name << '\n';
diff --git a/lib/Target/Mips/MipsTargetAsmInfo.cpp b/lib/Target/Mips/MipsTargetAsmInfo.cpp
index 7566f41eaf..3eee3beef1 100644
--- a/lib/Target/Mips/MipsTargetAsmInfo.cpp
+++ b/lib/Target/Mips/MipsTargetAsmInfo.cpp
@@ -85,7 +85,7 @@ SelectSectionForGlobal(const GlobalValue *GV) const {
   SectionKind::Kind K = SectionKindForGlobal(GV);
   const GlobalVariable *GVA = dyn_cast<GlobalVariable>(GV);
 
-  if (GVA && (!GVA->mayBeOverridden()))
+  if (GVA && (!GVA->isWeakForLinker()))
     switch (K) {
       case SectionKind::SmallData:
         return getSmallDataSection();
diff --git a/lib/Target/PowerPC/AsmPrinter/PPCAsmPrinter.cpp b/lib/Target/PowerPC/AsmPrinter/PPCAsmPrinter.cpp
index 57a2697112..4da53774d7 100644
--- a/lib/Target/PowerPC/AsmPrinter/PPCAsmPrinter.cpp
+++ b/lib/Target/PowerPC/AsmPrinter/PPCAsmPrinter.cpp
@@ -388,7 +388,7 @@ void PPCAsmPrinter::printOp(const MachineOperand &MO) {
 
     // External or weakly linked global variables need non-lazily-resolved stubs
     if (TM.getRelocationModel() != Reloc::Static) {
-      if (GV->isDeclaration() || GV->mayBeOverridden()) {
+      if (GV->isDeclaration() || GV->isWeakForLinker()) {
         if (GV->hasHiddenVisibility()) {
           if (!GV->isDeclaration() && !GV->hasCommonLinkage())
             O << Name;
@@ -592,8 +592,10 @@ bool PPCLinuxAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
     O << "\t.global\t" << CurrentFnName << '\n'
       << "\t.type\t" << CurrentFnName << ", @function\n";
     break;
-  case Function::WeakLinkage:
-  case Function::LinkOnceLinkage:
+  case Function::WeakAnyLinkage:
+  case Function::WeakODRLinkage:
+  case Function::LinkOnceAnyLinkage:
+  case Function::LinkOnceODRLinkage:
     O << "\t.global\t" << CurrentFnName << '\n';
     O << "\t.weak\t" << CurrentFnName << '\n';
     break;
@@ -689,7 +691,7 @@ void PPCLinuxAsmPrinter::printModuleLevelGV(const GlobalVariable* GVar) {
   if (C->isNullValue() && /* FIXME: Verify correct */
       !GVar->hasSection() &&
       (GVar->hasLocalLinkage() || GVar->hasExternalLinkage() ||
-       GVar->mayBeOverridden())) {
+       GVar->isWeakForLinker())) {
       if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
 
       if (GVar->hasExternalLinkage()) {
@@ -709,9 +711,12 @@ void PPCLinuxAsmPrinter::printModuleLevelGV(const GlobalVariable* GVar) {
   }
 
   switch (GVar->getLinkage()) {
-   case GlobalValue::LinkOnceLinkage:
-   case GlobalValue::WeakLinkage:
-   case GlobalValue::CommonLinkage:
+   case GlobalValue::LinkOnceAnyLinkage:
+   case GlobalValue::LinkOnceODRLinkage:
+   case GlobalValue::WeakAnyLinkage:
+   case GlobalValue::WeakODRLinkage:
+   case GlobalValue::CommonAnyLinkage:
+   case GlobalValue::CommonODRLinkage:
     O << "\t.global " << name << '\n'
       << "\t.type " << name << ", @object\n"
       << "\t.weak " << name << '\n';
@@ -785,8 +790,10 @@ bool PPCDarwinAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
   case Function::ExternalLinkage:
     O << "\t.globl\t" << CurrentFnName << '\n';
     break;
-  case Function::WeakLinkage:
-  case Function::LinkOnceLinkage:
+  case Function::WeakAnyLinkage:
+  case Function::WeakODRLinkage:
+  case Function::LinkOnceAnyLinkage:
+  case Function::LinkOnceODRLinkage:
     O << "\t.globl\t" << CurrentFnName << '\n';
     O << "\t.weak_definition\t" << CurrentFnName << '\n';
     break;
@@ -918,7 +925,7 @@ void PPCDarwinAsmPrinter::printModuleLevelGV(const GlobalVariable* GVar) {
   if (C->isNullValue() && /* FIXME: Verify correct */
       !GVar->hasSection() &&
       (GVar->hasLocalLinkage() || GVar->hasExternalLinkage() ||
-       GVar->mayBeOverridden()) &&
+       GVar->isWeakForLinker()) &&
       TAI->SectionKindForGlobal(GVar) != SectionKind::RODataMergeStr) {
     if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
 
@@ -950,9 +957,12 @@ void PPCDarwinAsmPrinter::printModuleLevelGV(const GlobalVariable* GVar) {
   }
 
   switch (GVar->getLinkage()) {
-   case GlobalValue::LinkOnceLinkage:
-   case GlobalValue::WeakLinkage:
-   case GlobalValue::CommonLinkage:
+   case GlobalValue::LinkOnceAnyLinkage:
+   case GlobalValue::LinkOnceODRLinkage:
+   case GlobalValue::WeakAnyLinkage:
+   case GlobalValue::WeakODRLinkage:
+   case GlobalValue::CommonAnyLinkage:
+   case GlobalValue::CommonODRLinkage:
     O << "\t.globl " << name << '\n'
       << "\t.weak_definition " << name << '\n';
     break;
diff --git a/lib/Target/Sparc/AsmPrinter/SparcAsmPrinter.cpp b/lib/Target/Sparc/AsmPrinter/SparcAsmPrinter.cpp
index 80976bb259..e0785d5582 100644
--- a/lib/Target/Sparc/AsmPrinter/SparcAsmPrinter.cpp
+++ b/lib/Target/Sparc/AsmPrinter/SparcAsmPrinter.cpp
@@ -260,7 +260,7 @@ void SparcAsmPrinter::printModuleLevelGV(const GlobalVariable* GVar) {
 
   if (C->isNullValue() && !GVar->hasSection()) {
     if (!GVar->isThreadLocal() &&
-        (GVar->hasLocalLinkage() || GVar->mayBeOverridden())) {
+        (GVar->hasLocalLinkage() || GVar->isWeakForLinker())) {
       if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
 
       if (GVar->hasLocalLinkage())
@@ -276,9 +276,12 @@ void SparcAsmPrinter::printModuleLevelGV(const GlobalVariable* GVar) {
   }
 
   switch (GVar->getLinkage()) {
-   case GlobalValue::CommonLinkage:
-   case GlobalValue::LinkOnceLinkage:
-   case GlobalValue::WeakLinkage:   // FIXME: Verify correct for weak.
+   case GlobalValue::CommonAnyLinkage:
+   case GlobalValue::CommonODRLinkage:
+   case GlobalValue::LinkOnceAnyLinkage:
+   case GlobalValue::LinkOnceODRLinkage:
+   case GlobalValue::WeakAnyLinkage: // FIXME: Verify correct for weak.
+   case GlobalValue::WeakODRLinkage: // FIXME: Verify correct for weak.
     // Nonnull linkonce -> weak
     O << "\t.weak " << name << '\n';
     break;
diff --git a/lib/Target/TargetAsmInfo.cpp b/lib/Target/TargetAsmInfo.cpp
index d687e2f44c..8f5941fb9e 100644
--- a/lib/Target/TargetAsmInfo.cpp
+++ b/lib/Target/TargetAsmInfo.cpp
@@ -259,7 +259,7 @@ TargetAsmInfo::SectionFlagsForGlobal(const GlobalValue *GV,
       assert(0 && "Unexpected section kind!");
     }
 
-    if (GV->mayBeOverridden())
+    if (GV->isWeakForLinker())
       Flags |= SectionFlags::Linkonce;
   }
 
@@ -310,7 +310,7 @@ const Section*
 TargetAsmInfo::SelectSectionForGlobal(const GlobalValue *GV) const {
   SectionKind::Kind Kind = SectionKindForGlobal(GV);
 
-  if (GV->mayBeOverridden()) {
+  if (GV->isWeakForLinker()) {
     std::string Name = UniqueSectionForGlobal(GV, Kind);
     unsigned Flags = SectionFlagsForGlobal(GV, Name.c_str());
     return getNamedSection(Name.c_str(), Flags);
diff --git a/lib/Target/X86/AsmPrinter/X86ATTAsmPrinter.cpp b/lib/Target/X86/AsmPrinter/X86ATTAsmPrinter.cpp
index 0595b6fbd1..e3b6c27dcb 100644
--- a/lib/Target/X86/AsmPrinter/X86ATTAsmPrinter.cpp
+++ b/lib/Target/X86/AsmPrinter/X86ATTAsmPrinter.cpp
@@ -168,8 +168,10 @@ void X86ATTAsmPrinter::emitFunctionHeader(const MachineFunction &MF) {
     EmitAlignment(FnAlign, F);
     O << "\t.globl\t" << CurrentFnName << '\n';
     break;
-  case Function::LinkOnceLinkage:
-  case Function::WeakLinkage:
+  case Function::LinkOnceAnyLinkage:
+  case Function::LinkOnceODRLinkage:
+  case Function::WeakAnyLinkage:
+  case Function::WeakODRLinkage:
     EmitAlignment(FnAlign, F);
     if (Subtarget->isTargetDarwin()) {
       O << "\t.globl\t" << CurrentFnName << '\n';
@@ -198,8 +200,7 @@ void X86ATTAsmPrinter::emitFunctionHeader(const MachineFunction &MF) {
   O << CurrentFnName << ":\n";
   // Add some workaround for linkonce linkage on Cygwin\MinGW
   if (Subtarget->isTargetCygMing() &&
-      (F->getLinkage() == Function::LinkOnceLinkage ||
-       F->getLinkage() == Function::WeakLinkage))
+      (F->hasLinkOnceLinkage() || F->hasWeakLinkage()))
     O << "Lllvm$workaround$fake$stub$" << CurrentFnName << ":\n";
 }
 
@@ -386,7 +387,7 @@ void X86ATTAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
     if (shouldPrintStub(TM, Subtarget)) {
       // Link-once, declaration, or Weakly-linked global variables need
       // non-lazily-resolved stubs
-      if (GV->isDeclaration() || GV->mayBeOverridden()) {
+      if (GV->isDeclaration() || GV->isWeakForLinker()) {
         // Dynamically-resolved functions need a stub for the function.
         if (isCallOp && isa<Function>(GV)) {
           // Function stubs are no longer needed for Mac OS X 10.5 and up.
@@ -816,7 +817,7 @@ void X86ATTAsmPrinter::printModuleLevelGV(const GlobalVariable* GVar) {
     }
 
     if (!GVar->isThreadLocal() &&
-        (GVar->hasLocalLinkage() || GVar->mayBeOverridden())) {
+        (GVar->hasLocalLinkage() || GVar->isWeakForLinker())) {
       if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
 
       if (TAI->getLCOMMDirective() != NULL) {
@@ -855,9 +856,12 @@ void X86ATTAsmPrinter::printModuleLevelGV(const GlobalVariable* GVar) {
   }
 
   switch (GVar->getLinkage()) {
-  case GlobalValue::CommonLinkage:
-  case GlobalValue::LinkOnceLinkage:
-  case GlobalValue::WeakLinkage:
+  case GlobalValue::CommonAnyLinkage:
+  case GlobalValue::CommonODRLinkage:
+  case GlobalValue::LinkOnceAnyLinkage:
+  case GlobalValue::LinkOnceODRLinkage:
+  case GlobalValue::WeakAnyLinkage:
+  case GlobalValue::WeakODRLinkage:
     if (Subtarget->isTargetDarwin()) {
       O << "\t.globl " << name << '\n'
         << TAI->getWeakDefDirective() << name << '\n';
diff --git a/lib/Target/X86/AsmPrinter/X86IntelAsmPrinter.cpp b/lib/Target/X86/AsmPrinter/X86IntelAsmPrinter.cpp
index c4389aa406..12b9c2fd4a 100644
--- a/lib/Target/X86/AsmPrinter/X86IntelAsmPrinter.cpp
+++ b/lib/Target/X86/AsmPrinter/X86IntelAsmPrinter.cpp
@@ -455,9 +455,12 @@ bool X86IntelAsmPrinter::doFinalization(Module &M) {
     bool bCustomSegment = false;
 
     switch (I->getLinkage()) {
-    case GlobalValue::CommonLinkage:
-    case GlobalValue::LinkOnceLinkage:
-    case GlobalValue::WeakLinkage:
+    case GlobalValue::CommonAnyLinkage:
+    case GlobalValue::CommonODRLinkage:
+    case GlobalValue::LinkOnceAnyLinkage:
+    case GlobalValue::LinkOnceODRLinkage:
+    case GlobalValue::WeakAnyLinkage:
+    case GlobalValue::WeakODRLinkage:
       SwitchToDataSection("");
       O << name << "?\tsegment common 'COMMON'\n";
       bCustomSegment = true;
diff --git a/lib/Target/X86/X86Subtarget.cpp b/lib/Target/X86/X86Subtarget.cpp
index 6d2602a2ce..8c5176bc83 100644
--- a/lib/Target/X86/X86Subtarget.cpp
+++ b/lib/Target/X86/X86Subtarget.cpp
@@ -51,7 +51,7 @@ bool X86Subtarget::GVRequiresExtraLoad(const GlobalValue* GV,
         // target is x86-64 or the symbol is definitely defined in the current
         // translation unit.
         return false;
-      return !isDirectCall && (isDecl || GV->mayBeOverridden());
+      return !isDirectCall && (isDecl || GV->isWeakForLinker());
     } else if (isTargetELF()) {
       // Extra load is needed for all externally visible.
       if (isDirectCall)
diff --git a/lib/Target/XCore/XCoreAsmPrinter.cpp b/lib/Target/XCore/XCoreAsmPrinter.cpp
index 3a30f107d8..6026e126d1 100644
--- a/lib/Target/XCore/XCoreAsmPrinter.cpp
+++ b/lib/Target/XCore/XCoreAsmPrinter.cpp
@@ -188,8 +188,10 @@ emitGlobal(const GlobalVariable *GV)
     case GlobalValue::AppendingLinkage:
       cerr << "AppendingLinkage is not supported by this target!\n";
       abort();
-    case GlobalValue::LinkOnceLinkage:
-    case GlobalValue::WeakLinkage:
+    case GlobalValue::LinkOnceAnyLinkage:
+    case GlobalValue::LinkOnceODRLinkage:
+    case GlobalValue::WeakAnyLinkage:
+    case GlobalValue::WeakODRLinkage:
     case GlobalValue::ExternalLinkage:
       emitArrayBound(name, GV);
       emitGlobalDirective(name);
@@ -266,8 +268,10 @@ emitFunctionStart(MachineFunction &MF)
   case Function::ExternalLinkage:
     emitGlobalDirective(CurrentFnName);
     break;
-  case Function::LinkOnceLinkage:
-  case Function::WeakLinkage:
+  case Function::LinkOnceAnyLinkage:
+  case Function::LinkOnceODRLinkage:
+  case Function::WeakAnyLinkage:
+  case Function::WeakODRLinkage:
     // TODO Use COMDAT groups for LinkOnceLinkage
     O << TAI->getGlobalDirective() << CurrentFnName << "\n";
     O << TAI->getWeakDefDirective() << CurrentFnName << "\n";
@@ -434,7 +438,8 @@ bool XCoreAsmPrinter::doInitialization(Module &M) {
       switch (I->getLinkage()) {
       default:
         assert(0 && "Unexpected linkage");
-      case Function::ExternalWeakLinkage:
+      case Function::ExternalWeakAnyLinkage:
+      case Function::ExternalWeakODRLinkage:
         ExtWeakSymbols.insert(I);
         // fallthrough
       case Function::ExternalLinkage:
diff --git a/lib/Target/XCore/XCoreTargetAsmInfo.cpp b/lib/Target/XCore/XCoreTargetAsmInfo.cpp
index 847224c766..78eb90c3b1 100644
--- a/lib/Target/XCore/XCoreTargetAsmInfo.cpp
+++ b/lib/Target/XCore/XCoreTargetAsmInfo.cpp
@@ -73,7 +73,7 @@ XCoreTargetAsmInfo::SelectSectionForGlobal(const GlobalValue *GV) const {
 
   if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
   {
-    if (!GVar->mayBeOverridden()) {
+    if (!GVar->isWeakForLinker()) {
       switch (Kind) {
       case SectionKind::RODataMergeStr:
         return MergeableStringSection(GVar);