Revert "[PPC] Use alias symbols in address computation."

This reverts commit r209638 because it broke self-hosting on ppc64/Linux. (the
Clang-compiled TableGen would segfault because it jumped to an invalid address
from within _ZNK4llvm17ManagedStaticBase21RegisterManagedStaticEPFPvvEPFvS1_E
(which is within the command-line parameter registration process)).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209745 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 34 insertions, 46 deletions

diff --git a/lib/Target/PowerPC/PPCAsmPrinter.cpp b/lib/Target/PowerPC/PPCAsmPrinter.cpp
index e89fb2d58a..2174b18715 100644
--- a/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ b/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -380,12 +380,15 @@ void PPCAsmPrinter::EmitInstruction(const MachineInstr *MI) {
     bool IsAvailExt = false;
 
     if (MO.isGlobal()) {
-      const GlobalValue *GV = MO.getGlobal();
-      MOSymbol = getSymbol(GV);
-      IsExternal = GV->isDeclaration();
-      IsCommon = GV->hasCommonLinkage();
-      IsFunction = GV->getType()->getElementType()->isFunctionTy();
-      IsAvailExt = GV->hasAvailableExternallyLinkage();
+      const GlobalValue *GValue = MO.getGlobal();
+      const GlobalAlias *GAlias = dyn_cast<GlobalAlias>(GValue);
+      const GlobalValue *RealGValue = GAlias ? GAlias->getAliasee() : GValue;
+      MOSymbol = getSymbol(RealGValue);
+      const GlobalVariable *GVar = dyn_cast<GlobalVariable>(RealGValue);
+      IsExternal = GVar && !GVar->hasInitializer();
+      IsCommon = GVar && RealGValue->hasCommonLinkage();
+      IsFunction = !GVar;
+      IsAvailExt = GVar && RealGValue->hasAvailableExternallyLinkage();
     } else if (MO.isCPI())
       MOSymbol = GetCPISymbol(MO.getIndex());
     else if (MO.isJTI())
@@ -424,9 +427,13 @@ void PPCAsmPrinter::EmitInstruction(const MachineInstr *MI) {
     }
     else if (MO.isGlobal()) {
       const GlobalValue *GValue = MO.getGlobal();
-      MOSymbol = getSymbol(GValue);
-      if (GValue->isDeclaration() || GValue->hasCommonLinkage() ||
-          GValue->hasAvailableExternallyLinkage() ||
+      const GlobalAlias *GAlias = dyn_cast<GlobalAlias>(GValue);
+      const GlobalValue *RealGValue = GAlias ? GAlias->getAliasee() : GValue;
+      MOSymbol = getSymbol(RealGValue);
+      const GlobalVariable *GVar = dyn_cast<GlobalVariable>(RealGValue);
+    
+      if (!GVar || !GVar->hasInitializer() || RealGValue->hasCommonLinkage() ||
+          RealGValue->hasAvailableExternallyLinkage() ||
           TM.getCodeModel() == CodeModel::Large)
         MOSymbol = lookUpOrCreateTOCEntry(MOSymbol);
     }
@@ -453,10 +460,13 @@ void PPCAsmPrinter::EmitInstruction(const MachineInstr *MI) {
     bool IsFunction = false;
 
     if (MO.isGlobal()) {
-      const GlobalValue *GV = MO.getGlobal();
-      MOSymbol = getSymbol(GV);
-      IsExternal = GV->isDeclaration();
-      IsFunction = GV->getType()->getElementType()->isFunctionTy();
+      const GlobalValue *GValue = MO.getGlobal();
+      const GlobalAlias *GAlias = dyn_cast<GlobalAlias>(GValue);
+      const GlobalValue *RealGValue = GAlias ? GAlias->getAliasee() : GValue;
+      MOSymbol = getSymbol(RealGValue);
+      const GlobalVariable *GVar = dyn_cast<GlobalVariable>(RealGValue);
+      IsExternal = GVar && !GVar->hasInitializer();
+      IsFunction = !GVar;
     } else if (MO.isCPI())
       MOSymbol = GetCPISymbol(MO.getIndex());
 
diff --git a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index 251e8b6246..f6e075d271 100644
--- a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -1472,8 +1472,17 @@ SDNode *PPCDAGToDAGISel::Select(SDNode *N) {
 
     if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(GA)) {
       const GlobalValue *GValue = G->getGlobal();
-      if (GValue->isDeclaration() || GValue->hasCommonLinkage() ||
-        GValue->hasAvailableExternallyLinkage())
+      const GlobalAlias *GAlias = dyn_cast<GlobalAlias>(GValue);
+      const GlobalValue *RealGValue = GAlias ? GAlias->getAliasee() : 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() || RealGValue->hasCommonLinkage() ||
+          RealGValue->hasAvailableExternallyLinkage())
         return CurDAG->getMachineNode(PPC::LDtocL, dl, MVT::i64, GA,
                                       SDValue(Tmp, 0));
     }
diff --git a/test/CodeGen/PowerPC/alias.ll b/test/CodeGen/PowerPC/alias.ll
deleted file mode 100644
index 86e41148a0..0000000000
--- a/test/CodeGen/PowerPC/alias.ll
+++ /dev/null
@@ -1,31 +0,0 @@
-; RUN: llc < %s -mtriple=powerpc64-unknown-linux-gnu -code-model=medium| FileCheck --check-prefix=CHECK --check-prefix=MEDIUM %s
-; RUN: llc < %s -mtriple=powerpc64-unknown-linux-gnu -code-model=large | FileCheck --check-prefix=CHECK --check-prefix=LARGE %s
-
-@foo = global i32 42
-@fooa = alias i32* @foo
-
-@foo2 = global i64 42
-@foo2a = alias i64* @foo2
-
-; CHECK-LABEL: bar:
-define i32 @bar() {
-; MEDIUM: addis 3, 2, fooa@toc@ha
-; LARGE: addis 3, 2, .LC1@toc@ha
-  %a = load i32* @fooa
-  ret i32 %a
-}
-
-; CHECK-LABEL: bar2:
-define i64 @bar2() {
-; MEDIUM: addis 3, 2, foo2a@toc@ha
-; MEDIUM: addi 3, 3, foo2a@toc@l
-; LARGE: addis 3, 2, .LC3@toc@ha
-  %a = load i64* @foo2a
-  ret i64 %a
-}
-
-; LARGE: .LC1:
-; LARGE-NEXT: .tc fooa[TC],fooa
-
-; LARGE: .LC3:
-; LARGE-NEXT: .tc foo2a[TC],foo2a