Merge pull request #3513 from compnerd/export-force-load

IRGen: give the force load symbol export DLL storage

Author: modocache

lib/IRGen/IRGenModule.cpp

@@ -975,10 +975,13 @@ void IRGenModule::emitAutolinkInfo() {
   if (!IRGen.Opts.ForceLoadSymbolName.empty()) {
     llvm::SmallString<64> buf;
     encodeForceLoadSymbolName(buf, IRGen.Opts.ForceLoadSymbolName);
-    (void)new llvm::GlobalVariable(Module, Int1Ty, /*constant=*/false,
-                                   llvm::GlobalValue::CommonLinkage,
-                                   llvm::Constant::getNullValue(Int1Ty),
-                                   buf.str());
+    auto symbol =
+        new llvm::GlobalVariable(Module, Int1Ty, /*constant=*/false,
+                                 llvm::GlobalValue::CommonLinkage,
+                                 llvm::Constant::getNullValue(Int1Ty),
+                                 buf.str());
+    if (Triple.isOSBinFormatCOFF())
+      symbol->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
   }
 }
 

test/IRGen/autolink-coff-force-link.swift

@@ -0,0 +1,11 @@
+// RUN: rm -rf %t
+// RUN: mkdir -p %t
+
+// RUN: %swift -target i686--windows-msvc -parse-as-library -parse-stdlib -module-name autolink -module-link-name autolink -autolink-force-load -emit-ir -o - %s | FileCheck %s
+// RUN: %swift -target i686--windows-itanium -parse-as-library -parse-stdlib -module-name autolink -module-link-name autolink -autolink-force-load -S -o - %s | FileCheck %s -check-prefix CHECK-ASM-GNU
+// RUN: %swift -target i686--windows-msvc -parse-as-library -parse-stdlib -module-name autolink -module-link-name autolink -autolink-force-load -S -o - %s | FileCheck %s -check-prefix CHECK-ASM-MSC
+
+// CHECK: @"_swift_FORCE_LOAD_$_autolink" = common dllexport global i1 false
+// CHECK-ASM-GNU: .ascii  " -export:__swift_FORCE_LOAD_$_autolink,data"
+// CHECK-ASM-MSC: .ascii  " /EXPORT:__swift_FORCE_LOAD_$_autolink,DATA"
+