3 files changed, 31 insertions, 36 deletions

diff --git a/lib/CodeGen/CGBlocks.cpp b/lib/CodeGen/CGBlocks.cpp
index 8269b5b229a2..906b98bfbafe 100644
--- a/lib/CodeGen/CGBlocks.cpp
+++ b/lib/CodeGen/CGBlocks.cpp
@@ -1213,9 +1213,13 @@ static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM,
   auto fields = builder.beginStruct();
 
   bool IsOpenCL = CGM.getLangOpts().OpenCL;
+  bool IsWindows = CGM.getTarget().getTriple().isOSWindows();
   if (!IsOpenCL) {
     // isa
-    fields.add(CGM.getNSConcreteGlobalBlock());
+    if (IsWindows)
+      fields.addNullPointer(CGM.Int8PtrPtrTy);
+    else
+      fields.add(CGM.getNSConcreteGlobalBlock());
 
     // __flags
     BlockFlags flags = BLOCK_IS_GLOBAL | BLOCK_HAS_SIGNATURE;
@@ -1250,7 +1254,27 @@ static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM,
 
   llvm::Constant *literal = fields.finishAndCreateGlobal(
       "__block_literal_global", blockInfo.BlockAlign,
-      /*constant*/ true, llvm::GlobalVariable::InternalLinkage, AddrSpace);
+      /*constant*/ !IsWindows, llvm::GlobalVariable::InternalLinkage, AddrSpace);
+
+  // Windows does not allow globals to be initialised to point to globals in
+  // different DLLs.  Any such variables must run code to initialise them.
+  if (IsWindows) {
+    auto *Init = llvm::Function::Create(llvm::FunctionType::get(CGM.VoidTy,
+          {}), llvm::GlobalValue::InternalLinkage, ".block_isa_init",
+        &CGM.getModule());
+    llvm::IRBuilder<> b(llvm::BasicBlock::Create(CGM.getLLVMContext(), "entry",
+          Init));
+    b.CreateAlignedStore(CGM.getNSConcreteGlobalBlock(),
+        b.CreateStructGEP(literal, 0), CGM.getPointerAlign().getQuantity());
+    b.CreateRetVoid();
+    // We can't use the normal LLVM global initialisation array, because we
+    // need to specify that this runs early in library initialisation.
+    auto *InitVar = new llvm::GlobalVariable(CGM.getModule(), Init->getType(),
+        /*isConstant*/true, llvm::GlobalValue::InternalLinkage,
+        Init, ".block_isa_init_ptr");
+    InitVar->setSection(".CRT$XCLa");
+    CGM.addUsedGlobal(InitVar);
+  }
 
   // Return a constant of the appropriately-casted type.
   llvm::Type *RequiredType =
diff --git a/lib/CodeGen/CGObjCGNU.cpp b/lib/CodeGen/CGObjCGNU.cpp
index 3e994edc976b..915738b8b301 100644
--- a/lib/CodeGen/CGObjCGNU.cpp
+++ b/lib/CodeGen/CGObjCGNU.cpp
@@ -3812,40 +3812,10 @@ llvm::GlobalVariable *CGObjCGNU::ObjCIvarOffsetVariable(
   // is.  This allows code compiled with non-fragile ivars to work correctly
   // when linked against code which isn't (most of the time).
   llvm::GlobalVariable *IvarOffsetPointer = TheModule.getNamedGlobal(Name);
-  if (!IvarOffsetPointer) {
-    // This will cause a run-time crash if we accidentally use it.  A value of
-    // 0 would seem more sensible, but will silently overwrite the isa pointer
-    // causing a great deal of confusion.
-    uint64_t Offset = -1;
-    // We can't call ComputeIvarBaseOffset() here if we have the
-    // implementation, because it will create an invalid ASTRecordLayout object
-    // that we are then stuck with forever, so we only initialize the ivar
-    // offset variable with a guess if we only have the interface.  The
-    // initializer will be reset later anyway, when we are generating the class
-    // description.
-    if (!CGM.getContext().getObjCImplementation(
-              const_cast<ObjCInterfaceDecl *>(ID)))
-      Offset = ComputeIvarBaseOffset(CGM, ID, Ivar);
-
-    llvm::ConstantInt *OffsetGuess = llvm::ConstantInt::get(Int32Ty, Offset,
-                             /*isSigned*/true);
-    // Don't emit the guess in non-PIC code because the linker will not be able
-    // to replace it with the real version for a library.  In non-PIC code you
-    // must compile with the fragile ABI if you want to use ivars from a
-    // GCC-compiled class.
-    if (CGM.getLangOpts().PICLevel) {
-      llvm::GlobalVariable *IvarOffsetGV = new llvm::GlobalVariable(TheModule,
-            Int32Ty, false,
-            llvm::GlobalValue::PrivateLinkage, OffsetGuess, Name+".guess");
-      IvarOffsetPointer = new llvm::GlobalVariable(TheModule,
-            IvarOffsetGV->getType(), false, llvm::GlobalValue::LinkOnceAnyLinkage,
-            IvarOffsetGV, Name);
-    } else {
-      IvarOffsetPointer = new llvm::GlobalVariable(TheModule,
-              llvm::Type::getInt32PtrTy(VMContext), false,
-              llvm::GlobalValue::ExternalLinkage, nullptr, Name);
-    }
-  }
+  if (!IvarOffsetPointer)
+    IvarOffsetPointer = new llvm::GlobalVariable(TheModule,
+            llvm::Type::getInt32PtrTy(VMContext), false,
+            llvm::GlobalValue::ExternalLinkage, nullptr, Name);
   return IvarOffsetPointer;
 }
 
diff --git a/lib/CodeGen/CodeGenAction.cpp b/lib/CodeGen/CodeGenAction.cpp
index d499364002f0..1a2b0616dc77 100644
--- a/lib/CodeGen/CodeGenAction.cpp
+++ b/lib/CodeGen/CodeGenAction.cpp
@@ -127,6 +127,7 @@ namespace clang {
                                 CodeGenOpts, C, CoverageInfo)),
           LinkModules(std::move(LinkModules)) {
       FrontendTimesIsEnabled = TimePasses;
+      llvm::TimePassesIsEnabled = TimePasses;
     }
     llvm::Module *getModule() const { return Gen->GetModule(); }
     std::unique_ptr<llvm::Module> takeModule() {