Update for LLVM API change D20147.

lib/IRGen/GenInit.cpp

@@ -41,11 +41,10 @@ Address IRGenModule::emitSILGlobalVariable(SILGlobalVariable *var) {
   // just return undef.
   if (ti.isKnownEmpty(ResilienceExpansion::Minimal)) {
     if (DebugInfo && var->getDecl()) {
-      auto Zero = llvm::ConstantInt::get(Int64Ty, 0);
       DebugTypeInfo DbgTy(var->getDecl(), var->getLoweredType().getSwiftType(),
                           Int8Ty, Size(0), Alignment(1));
       DebugInfo->emitGlobalVariableDeclaration(
-          Zero, var->getDecl()->getName().str(), "", DbgTy,
+          nullptr, var->getDecl()->getName().str(), "", DbgTy,
           var->getLinkage() != SILLinkage::Public, SILLocation(var->getDecl()));
     }
     return ti.getUndefAddress();

lib/IRGen/IRGenDebugInfo.cpp

@@ -999,13 +999,9 @@ void IRGenDebugInfo::emitDbgIntrinsic(llvm::BasicBlock *BB,
     DBuilder.insertDbgValueIntrinsic(Storage, 0, Var, Expr, DL, BB);
 }
 
-
-void IRGenDebugInfo::emitGlobalVariableDeclaration(llvm::Constant *Var,
-                                                   StringRef Name,
-                                                   StringRef LinkageName,
-                                                   DebugTypeInfo DbgTy,
-                                                   bool IsLocalToUnit,
-                                                   Optional<SILLocation> Loc) {
+void IRGenDebugInfo::emitGlobalVariableDeclaration(
+    llvm::GlobalVariable *Var, StringRef Name, StringRef LinkageName,
+    DebugTypeInfo DbgTy, bool IsLocalToUnit, Optional<SILLocation> Loc) {
   if (Opts.DebugInfoKind <= IRGenDebugInfoKind::LineTables)
     return;
 
@@ -1021,8 +1017,11 @@ void IRGenDebugInfo::emitGlobalVariableDeclaration(llvm::Constant *Var,
   auto File = getOrCreateFile(L.Filename);
 
   // Emit it as global variable of the current module.
-  DBuilder.createGlobalVariable(MainModule, Name, LinkageName, File, L.Line, Ty,
-                                IsLocalToUnit, Var, nullptr);
+  auto *Expr = Var ? nullptr : DBuilder.createConstantValueExpression(0);
+  auto *GV = DBuilder.createGlobalVariable(MainModule, Name, LinkageName, File,
+                                           L.Line, Ty, IsLocalToUnit, Expr);
+  if (Var)
+    Var->addDebugInfo(GV);
 }
 
 StringRef IRGenDebugInfo::getMangledName(DebugTypeInfo DbgTy) {

lib/IRGen/IRGenDebugInfo.h

@@ -194,8 +194,8 @@ class IRGenDebugInfo {
                         const SILDebugScope *DS);
 
   /// Create debug metadata for a global variable.
-  void emitGlobalVariableDeclaration(llvm::Constant *Storage, StringRef Name,
-                                     StringRef LinkageName,
+  void emitGlobalVariableDeclaration(llvm::GlobalVariable *Storage,
+                                     StringRef Name, StringRef LinkageName,
                                      DebugTypeInfo DebugType,
                                      bool IsLocalToUnit,
                                      Optional<SILLocation> Loc);

test/DebugInfo/enum.swift

@@ -1,8 +1,6 @@
 // RUN: %target-swift-frontend -primary-file %s -emit-ir -g -o - | %FileCheck %s
 // RUN: %target-swift-frontend -primary-file %s -emit-ir -gdwarf-types -o - | %FileCheck %s --check-prefix=DWARF
 
-// CHECK: ![[EMPTY:.*]] = !{}
-
 protocol P {}
 
 enum Either {
@@ -11,6 +9,7 @@ enum Either {
 // CHECK-SAME:             line: [[@LINE-3]],
 // CHECK-SAME:             size: {{328|168}},
 }
+// CHECK: ![[EMPTY:.*]] = !{}
 // DWARF: ![[INT:.*]] = !DICompositeType({{.*}}identifier: "_TtSi"
 let E : Either = .Neither;
 

test/DebugInfo/nostorage.swift

@@ -37,4 +37,5 @@ public func app() {
 public enum empty { case exists }
 public let globalvar = empty.exists
 // CHECK3: !DIGlobalVariable(name: "globalvar", {{.*}}line: [[@LINE-1]],
-// CHECK3-SAME:          isLocal: false, isDefinition: true, variable: i64 0)
+// CHECK3-SAME:          isLocal: false, isDefinition: true, expr: ![[ZERO:.*]])
+// CHECK3: ![[ZERO]] = !DIExpression(DW_OP_constu, 0, DW_OP_stack_value)