Add CommonLinkage; currently tentative definitions

are represented as "weak", but there are subtle differences
in some cases on Darwin, so we need both.  The intent
is that "common" will behave identically to "weak" unless
somebody changes their target to do something else.
No functional change as yet.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51118 91177308-0d34-0410-b5e6-96231b3b80d8

13 files changed, 37 insertions, 16 deletions

diff --git a/lib/Target/Alpha/AlphaAsmPrinter.cpp b/lib/Target/Alpha/AlphaAsmPrinter.cpp
index 42e4b7843c..2c289718f0 100644
--- a/lib/Target/Alpha/AlphaAsmPrinter.cpp
+++ b/lib/Target/Alpha/AlphaAsmPrinter.cpp
@@ -225,6 +225,7 @@ bool AlphaAsmPrinter::doFinalization(Module &M) {
     switch (I->getLinkage()) {
     case GlobalValue::LinkOnceLinkage:
     case GlobalValue::WeakLinkage:
+    case GlobalValue::CommonLinkage:
       O << TAI->getWeakRefDirective() << name << '\n';
       break;
     case GlobalValue::AppendingLinkage:
diff --git a/lib/Target/CBackend/CBackend.cpp b/lib/Target/CBackend/CBackend.cpp
index dcc920a64c..f52322bef2 100644
--- a/lib/Target/CBackend/CBackend.cpp
+++ b/lib/Target/CBackend/CBackend.cpp
@@ -1604,7 +1604,8 @@ bool CWriter::doInitialization(Module &M) {
     for (Module::global_iterator I = M.global_begin(), E = M.global_end();
          I != E; ++I) {
 
-      if (I->hasExternalLinkage() || I->hasExternalWeakLinkage())
+      if (I->hasExternalLinkage() || I->hasExternalWeakLinkage() || 
+          I->hasCommonLinkage())
         Out << "extern ";
       else if (I->hasDLLImportLinkage())
         Out << "__declspec(dllimport) ";
@@ -1678,6 +1679,8 @@ bool CWriter::doInitialization(Module &M) {
 
         if (I->hasLinkOnceLinkage())
           Out << " __attribute__((common))";
+        else if (I->hasCommonLinkage())     // FIXME is this right?
+          Out << " __ATTRIBUTE_WEAK__";
         else if (I->hasWeakLinkage())
           Out << " __ATTRIBUTE_WEAK__";
         else if (I->hasExternalWeakLinkage())
@@ -1715,6 +1718,8 @@ bool CWriter::doInitialization(Module &M) {
           Out << " __attribute__((common))";
         else if (I->hasWeakLinkage())
           Out << " __ATTRIBUTE_WEAK__";
+        else if (I->hasCommonLinkage())
+          Out << " __ATTRIBUTE_WEAK__";
 
         if (I->hasHiddenVisibility())
           Out << " __HIDDEN__";
@@ -1724,6 +1729,7 @@ bool CWriter::doInitialization(Module &M) {
         // this, however, occurs when the variable has weak linkage.  In this
         // case, the assembler will complain about the variable being both weak
         // and common, so we disable this optimization.
+        // FIXME common linkage should avoid this problem.
         if (!I->getInitializer()->isNullValue()) {
           Out << " = " ;
           writeOperand(I->getInitializer());
diff --git a/lib/Target/CellSPU/SPUAsmPrinter.cpp b/lib/Target/CellSPU/SPUAsmPrinter.cpp
index f627896f6b..4e4324bbef 100644
--- a/lib/Target/CellSPU/SPUAsmPrinter.cpp
+++ b/lib/Target/CellSPU/SPUAsmPrinter.cpp
@@ -340,7 +340,7 @@ void SPUAsmPrinter::printOp(const MachineOperand &MO) {
     // stubs
     if (TM.getRelocationModel() != Reloc::Static) {
       if (((GV->isDeclaration() || GV->hasWeakLinkage() ||
-            GV->hasLinkOnceLinkage()))) {
+            GV->hasLinkOnceLinkage() || GV->hasCommonLinkage()))) {
         GVStubs.insert(Name);
         O << "L" << Name << "$non_lazy_ptr";
         return;
@@ -510,7 +510,7 @@ bool LinuxAsmPrinter::doFinalization(Module &M) {
 
     if (C->isNullValue() && /* FIXME: Verify correct */
         (I->hasInternalLinkage() || I->hasWeakLinkage() ||
-         I->hasLinkOnceLinkage() ||
+         I->hasLinkOnceLinkage() || I->hasCommonLinkage() ||
          (I->hasExternalLinkage() && !I->hasSection()))) {
       if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
       if (I->hasExternalLinkage()) {
@@ -537,6 +537,7 @@ bool LinuxAsmPrinter::doFinalization(Module &M) {
       switch (I->getLinkage()) {
       case GlobalValue::LinkOnceLinkage:
       case GlobalValue::WeakLinkage:
+      case GlobalValue::CommonLinkage:
         O << "\t.global " << name << '\n'
           << "\t.weak_definition " << name << '\n';
         SwitchToDataSection(".section __DATA,__datacoal_nt,coalesced", I);
diff --git a/lib/Target/CppBackend/CPPBackend.cpp b/lib/Target/CppBackend/CPPBackend.cpp
index 87240731b5..dc9a11e457 100644
--- a/lib/Target/CppBackend/CPPBackend.cpp
+++ b/lib/Target/CppBackend/CPPBackend.cpp
@@ -301,6 +301,8 @@ namespace {
       Out << "GlobalValue::ExternalWeakLinkage"; break;
     case GlobalValue::GhostLinkage:
       Out << "GlobalValue::GhostLinkage"; break;
+    case GlobalValue::CommonLinkage:
+      Out << "GlobalValue::CommonLinkage"; break;
     }
   }
 
diff --git a/lib/Target/IA64/IA64AsmPrinter.cpp b/lib/Target/IA64/IA64AsmPrinter.cpp
index 829730da24..037687cbe9 100644
--- a/lib/Target/IA64/IA64AsmPrinter.cpp
+++ b/lib/Target/IA64/IA64AsmPrinter.cpp
@@ -275,6 +275,7 @@ bool IA64AsmPrinter::doFinalization(Module &M) {
 
       if (C->isNullValue() &&
           (I->hasLinkOnceLinkage() || I->hasInternalLinkage() ||
+           I->hasCommonLinkage() ||
            I->hasWeakLinkage() /* FIXME: Verify correct */)) {
         SwitchToDataSection(".data", I);
         if (I->hasInternalLinkage()) {
@@ -289,6 +290,7 @@ bool IA64AsmPrinter::doFinalization(Module &M) {
       } else {
         switch (I->getLinkage()) {
           case GlobalValue::LinkOnceLinkage:
+          case GlobalValue::CommonLinkage:
           case GlobalValue::WeakLinkage:   // FIXME: Verify correct for weak.
                                            // Nonnull linkonce -> weak
             O << "\t.weak " << name << "\n";
diff --git a/lib/Target/Mips/MipsAsmPrinter.cpp b/lib/Target/Mips/MipsAsmPrinter.cpp
index 6c0c908ae7..6ae6104cb2 100644
--- a/lib/Target/Mips/MipsAsmPrinter.cpp
+++ b/lib/Target/Mips/MipsAsmPrinter.cpp
@@ -461,7 +461,8 @@ doFinalization(Module &M)
 
       // Is this correct ?
       if (C->isNullValue() && (I->hasLinkOnceLinkage() || 
-          I->hasInternalLinkage() || I->hasWeakLinkage())) 
+          I->hasInternalLinkage() || I->hasWeakLinkage() ||
+          I->hasCommonLinkage()))
       {
         if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
 
@@ -487,7 +488,8 @@ doFinalization(Module &M)
         switch (I->getLinkage()) 
         {
           case GlobalValue::LinkOnceLinkage:
-          case GlobalValue::WeakLinkage:   
+          case GlobalValue::CommonLinkage:
+          case GlobalValue::WeakLinkage:
             // FIXME: Verify correct for weak.
             // Nonnull linkonce -> weak
             O << "\t.weak " << name << "\n";
diff --git a/lib/Target/PIC16/PIC16AsmPrinter.cpp b/lib/Target/PIC16/PIC16AsmPrinter.cpp
index f211face12..15711b5d01 100644
--- a/lib/Target/PIC16/PIC16AsmPrinter.cpp
+++ b/lib/Target/PIC16/PIC16AsmPrinter.cpp
@@ -414,7 +414,7 @@ bool PIC16AsmPrinter::doFinalization(Module &M)
 
       if (!I->hasSection() &&
           (I->hasInternalLinkage() || I->hasWeakLinkage() ||
-           I->hasLinkOnceLinkage())) {
+           I->hasLinkOnceLinkage() || I->hasCommonLinkage())) {
         if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
         if (!NoZerosInBSS && TAI->getBSSSection())
           SwitchToDataSection(M.getModuleIdentifier().c_str(), I);
diff --git a/lib/Target/PowerPC/PPCAsmPrinter.cpp b/lib/Target/PowerPC/PPCAsmPrinter.cpp
index 4cc9d2a9bd..96e1ae8a04 100644
--- a/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ b/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -185,7 +185,7 @@ namespace {
         if (MO.getType() == MachineOperand::MO_GlobalAddress) {
           GlobalValue *GV = MO.getGlobal();
           if (((GV->isDeclaration() || GV->hasWeakLinkage() ||
-                GV->hasLinkOnceLinkage()))) {
+                GV->hasLinkOnceLinkage() || GV->hasCommonLinkage()))) {
             // Dynamically-resolved functions need a stub for the function.
             std::string Name = Mang->getValueName(GV);
             FnStubs.insert(Name);
@@ -390,7 +390,7 @@ 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->hasWeakLinkage() ||
-            GV->hasLinkOnceLinkage()))) {
+            GV->hasLinkOnceLinkage() || GV->hasCommonLinkage()))) {
         GVStubs.insert(Name);
         O << "L" << Name << "$non_lazy_ptr";
         return;
@@ -671,8 +671,8 @@ bool LinuxAsmPrinter::doFinalization(Module &M) {
     unsigned Align = TD->getPreferredAlignmentLog(I);
 
     if (C->isNullValue() && /* FIXME: Verify correct */
-        !I->hasSection() &&
-        (I->hasInternalLinkage() || I->hasWeakLinkage() ||
+        !I->hasSection() && (I->hasCommonLinkage() ||
+         I->hasInternalLinkage() || I->hasWeakLinkage() ||
          I->hasLinkOnceLinkage() || I->hasExternalLinkage())) {
       if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
       if (I->hasExternalLinkage()) {
@@ -696,6 +696,7 @@ bool LinuxAsmPrinter::doFinalization(Module &M) {
       switch (I->getLinkage()) {
       case GlobalValue::LinkOnceLinkage:
       case GlobalValue::WeakLinkage:
+      case GlobalValue::CommonLinkage:
         O << "\t.global " << name << '\n'
           << "\t.type " << name << ", @object\n"
           << "\t.weak " << name << '\n';
@@ -936,8 +937,8 @@ bool DarwinAsmPrinter::doFinalization(Module &M) {
     unsigned Align = TD->getPreferredAlignmentLog(I);
 
     if (C->isNullValue() && /* FIXME: Verify correct */
-        !I->hasSection() &&
-        (I->hasInternalLinkage() || I->hasWeakLinkage() ||
+        !I->hasSection() && (I->hasCommonLinkage() ||
+         I->hasInternalLinkage() || I->hasWeakLinkage() ||
          I->hasLinkOnceLinkage() || I->hasExternalLinkage())) {
       if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
       if (I->hasExternalLinkage()) {
@@ -961,6 +962,7 @@ bool DarwinAsmPrinter::doFinalization(Module &M) {
       switch (I->getLinkage()) {
       case GlobalValue::LinkOnceLinkage:
       case GlobalValue::WeakLinkage:
+      case GlobalValue::CommonLinkage:
         O << "\t.globl " << name << '\n'
           << "\t.weak_definition " << name << '\n';
         SwitchToDataSection("\t.section __DATA,__datacoal_nt,coalesced", I);
diff --git a/lib/Target/Sparc/SparcAsmPrinter.cpp b/lib/Target/Sparc/SparcAsmPrinter.cpp
index 01bd0929bd..2011ab9803 100644
--- a/lib/Target/Sparc/SparcAsmPrinter.cpp
+++ b/lib/Target/Sparc/SparcAsmPrinter.cpp
@@ -231,8 +231,8 @@ bool SparcAsmPrinter::doFinalization(Module &M) {
       unsigned Size = TD->getABITypeSize(C->getType());
       unsigned Align = TD->getPreferredAlignment(I);
 
-      if (C->isNullValue() &&
-          (I->hasLinkOnceLinkage() || I->hasInternalLinkage() ||
+      if (C->isNullValue() && (I->hasCommonLinkage() ||
+           I->hasLinkOnceLinkage() || I->hasInternalLinkage() ||
            I->hasWeakLinkage() /* FIXME: Verify correct */)) {
         SwitchToDataSection(".data", I);
         if (I->hasInternalLinkage())
@@ -243,6 +243,7 @@ bool SparcAsmPrinter::doFinalization(Module &M) {
         O << "\n";
       } else {
         switch (I->getLinkage()) {
+        case GlobalValue::CommonLinkage:
         case GlobalValue::LinkOnceLinkage:
         case GlobalValue::WeakLinkage:   // FIXME: Verify correct for weak.
           // Nonnull linkonce -> weak
diff --git a/lib/Target/X86/X86ATTAsmPrinter.cpp b/lib/Target/X86/X86ATTAsmPrinter.cpp
index 6909da1b24..4659deb146 100644
--- a/lib/Target/X86/X86ATTAsmPrinter.cpp
+++ b/lib/Target/X86/X86ATTAsmPrinter.cpp
@@ -309,7 +309,8 @@ void X86ATTAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
       // non-lazily-resolved stubs
       if (GV->isDeclaration() ||
           GV->hasWeakLinkage() ||
-          GV->hasLinkOnceLinkage()) {
+          GV->hasLinkOnceLinkage() ||
+          GV->hasCommonLinkage()) {
         // Dynamically-resolved functions need a stub for the function.
         if (isCallOp && isa<Function>(GV)) {
           FnStubs.insert(Name);
diff --git a/lib/Target/X86/X86AsmPrinter.cpp b/lib/Target/X86/X86AsmPrinter.cpp
index e1bc65fc5d..3898a9ee46 100644
--- a/lib/Target/X86/X86AsmPrinter.cpp
+++ b/lib/Target/X86/X86AsmPrinter.cpp
@@ -200,7 +200,7 @@ bool X86SharedAsmPrinter::doFinalization(Module &M) {
       
       if (!I->isThreadLocal() &&
           (I->hasInternalLinkage() || I->hasWeakLinkage() ||
-           I->hasLinkOnceLinkage())) {
+           I->hasLinkOnceLinkage() || I->hasCommonLinkage())) {
         if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
         if (!NoZerosInBSS && TAI->getBSSSection())
           SwitchToDataSection(TAI->getBSSSection(), I);
@@ -235,6 +235,7 @@ bool X86SharedAsmPrinter::doFinalization(Module &M) {
     }
 
     switch (I->getLinkage()) {
+    case GlobalValue::CommonLinkage:
     case GlobalValue::LinkOnceLinkage:
     case GlobalValue::WeakLinkage:
       if (Subtarget->isTargetDarwin()) {
diff --git a/lib/Target/X86/X86IntelAsmPrinter.cpp b/lib/Target/X86/X86IntelAsmPrinter.cpp
index ddd90cd40a..a1031bd8ea 100644
--- a/lib/Target/X86/X86IntelAsmPrinter.cpp
+++ b/lib/Target/X86/X86IntelAsmPrinter.cpp
@@ -373,6 +373,7 @@ bool X86IntelAsmPrinter::doFinalization(Module &M) {
     bool bCustomSegment = false;
 
     switch (I->getLinkage()) {
+    case GlobalValue::CommonLinkage:
     case GlobalValue::LinkOnceLinkage:
     case GlobalValue::WeakLinkage:
       SwitchToDataSection("");
diff --git a/lib/Target/X86/X86Subtarget.cpp b/lib/Target/X86/X86Subtarget.cpp
index 98d80c84a0..23ceb9ba96 100644
--- a/lib/Target/X86/X86Subtarget.cpp
+++ b/lib/Target/X86/X86Subtarget.cpp
@@ -41,6 +41,7 @@ bool X86Subtarget::GVRequiresExtraLoad(const GlobalValue* GV,
     if (isTargetDarwin()) {
       return (!isDirectCall &&
               (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
+               GV->hasCommonLinkage() ||
                (GV->isDeclaration() && !GV->hasNotBeenReadFromBitcode())));
     } else if (isTargetELF()) {
       // Extra load is needed for all non-statics.