This patch addresses bug 14678 by fixing two problems in medium code model

code generation.  Variables addressed through a GlobalAlias were not being
handled, and variables with available_externally linkage were treated
incorrectly.  The patch contains two new tests to verify the correct code
generation for these cases.

llvm-svn: 171778

2 files changed, 29 insertions, 12 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
index 85f00ddc4b9..adb673b60c5 100644
--- a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -426,20 +426,25 @@ void PPCAsmPrinter::EmitInstruction(const MachineInstr *MI) {
     bool IsExternal = false;
     bool IsFunction = false;
     bool IsCommon = false;
+    bool IsAvailExt = false;
 
     if (MO.isGlobal()) {
       const GlobalValue *GValue = MO.getGlobal();
-      MOSymbol = Mang->getSymbol(GValue);
-      const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GValue);
+      const GlobalAlias *GAlias = dyn_cast<GlobalAlias>(GValue);
+      const GlobalValue *RealGValue = GAlias ?
+        GAlias->resolveAliasedGlobal(false) : GValue;
+      MOSymbol = Mang->getSymbol(RealGValue);
+      const GlobalVariable *GVar = dyn_cast<GlobalVariable>(RealGValue);
       IsExternal = GVar && !GVar->hasInitializer();
-      IsCommon = GVar && GValue->hasCommonLinkage();
+      IsCommon = GVar && RealGValue->hasCommonLinkage();
       IsFunction = !GVar;
+      IsAvailExt = GVar && RealGValue->hasAvailableExternallyLinkage();
     } else if (MO.isCPI())
       MOSymbol = GetCPISymbol(MO.getIndex());
     else if (MO.isJTI())
       MOSymbol = GetJTISymbol(MO.getIndex());
 
-    if (IsExternal || IsFunction || IsCommon || MO.isJTI())
+    if (IsExternal || IsFunction || IsCommon || IsAvailExt || MO.isJTI())
       MOSymbol = lookUpOrCreateTOCEntry(MOSymbol);
 
     const MCExpr *Exp =
@@ -466,10 +471,14 @@ void PPCAsmPrinter::EmitInstruction(const MachineInstr *MI) {
       MOSymbol = lookUpOrCreateTOCEntry(GetJTISymbol(MO.getIndex()));
     else {
       const GlobalValue *GValue = MO.getGlobal();
-      MOSymbol = Mang->getSymbol(GValue);
-      const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GValue);
+      const GlobalAlias *GAlias = dyn_cast<GlobalAlias>(GValue);
+      const GlobalValue *RealGValue = GAlias ?
+        GAlias->resolveAliasedGlobal(false) : GValue;
+      MOSymbol = Mang->getSymbol(RealGValue);
+      const GlobalVariable *GVar = dyn_cast<GlobalVariable>(RealGValue);
     
-      if (!GVar || !GVar->hasInitializer() || GValue->hasCommonLinkage())
+      if (!GVar || !GVar->hasInitializer() || RealGValue->hasCommonLinkage() ||
+          RealGValue->hasAvailableExternallyLinkage())
         MOSymbol = lookUpOrCreateTOCEntry(MOSymbol);
     }
 
@@ -496,8 +505,11 @@ void PPCAsmPrinter::EmitInstruction(const MachineInstr *MI) {
 
     if (MO.isGlobal()) {
       const GlobalValue *GValue = MO.getGlobal();
-      MOSymbol = Mang->getSymbol(GValue);
-      const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GValue);
+      const GlobalAlias *GAlias = dyn_cast<GlobalAlias>(GValue);
+      const GlobalValue *RealGValue = GAlias ?
+        GAlias->resolveAliasedGlobal(false) : GValue;
+      MOSymbol = Mang->getSymbol(RealGValue);
+      const GlobalVariable *GVar = dyn_cast<GlobalVariable>(RealGValue);
       IsExternal = GVar && !GVar->hasInitializer();
       IsFunction = !GVar;
     } else if (MO.isCPI())
diff --git a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index 9ac0a2731a1..762b3467c3e 100644
--- a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -25,6 +25,7 @@
 #include "llvm/IR/Function.h"
 #include "llvm/IR/GlobalValue.h"
 #include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/GlobalAlias.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -1296,14 +1297,18 @@ SDNode *PPCDAGToDAGISel::Select(SDNode *N) {
 
     if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(GA)) {
       const GlobalValue *GValue = G->getGlobal();
-      const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GValue);
-      assert((GVar || isa<Function>(GValue)) &&
+      const GlobalAlias *GAlias = dyn_cast<GlobalAlias>(GValue);
+      const GlobalValue *RealGValue = GAlias ?
+        GAlias->resolveAliasedGlobal(false) : GValue;
+      const GlobalVariable *GVar = dyn_cast<GlobalVariable>(RealGValue);
+      assert((GVar || isa<Function>(RealGValue)) &&
              "Unexpected global value subclass!");
 
       // An external variable is one without an initializer.  For these,
       // for variables with common linkage, and for Functions, generate
       // the LDtocL form.
-      if (!GVar || !GVar->hasInitializer() || GValue->hasCommonLinkage())
+      if (!GVar || !GVar->hasInitializer() || RealGValue->hasCommonLinkage() ||
+          RealGValue->hasAvailableExternallyLinkage())
         return CurDAG->getMachineNode(PPC::LDtocL, dl, MVT::i64, GA,
                                       SDValue(Tmp, 0));
     }