Fix IRGen datalayout

Same issue as with TBDGen. Clang doesn't hold onto the Datalayout object
anymore, but instead keeps the description string that is constructed on
the fly. This patch updates IRGen to behave the same way.

Author: etcwilde

lib/IRGen/IRGen.cpp

@@ -1533,7 +1533,7 @@ bool swift::performLLVM(const IRGenOptions &Opts, ASTContext &Ctx,
 
   auto *Clang = static_cast<ClangImporter *>(Ctx.getClangModuleLoader());
   // Use clang's datalayout.
-  Module->setDataLayout(Clang->getTargetInfo().getDataLayout());
+  Module->setDataLayout(Clang->getTargetInfo().getDataLayoutString());
 
   embedBitcode(Module, Opts);
   if (::performLLVM(Opts, Ctx.Diags, nullptr, nullptr, Module,

lib/IRGen/IRGenModule.cpp

@@ -192,19 +192,18 @@ static void sanityCheckStdlib(IRGenModule &IGM) {
 
 IRGenModule::IRGenModule(IRGenerator &irgen,
                          std::unique_ptr<llvm::TargetMachine> &&target,
-                         SourceFile *SF,
-                         StringRef ModuleName, StringRef OutputFilename,
+                         SourceFile *SF, StringRef ModuleName,
+                         StringRef OutputFilename,
                          StringRef MainInputFilenameForDebugInfo,
                          StringRef PrivateDiscriminator)
-    : LLVMContext(new llvm::LLVMContext()),
-      IRGen(irgen), Context(irgen.SIL.getASTContext()),
+    : LLVMContext(new llvm::LLVMContext()), IRGen(irgen),
+      Context(irgen.SIL.getASTContext()),
       // The LLVMContext (and the IGM itself) will get deleted by the IGMDeleter
       // as long as the IGM is registered with the IRGenerator.
-      ClangCodeGen(createClangCodeGenerator(Context, *LLVMContext,
-                                            irgen.Opts,
+      ClangCodeGen(createClangCodeGenerator(Context, *LLVMContext, irgen.Opts,
                                             ModuleName, PrivateDiscriminator)),
       Module(*ClangCodeGen->GetModule()),
-      DataLayout(irgen.getClangDataLayout()),
+      DataLayout(irgen.getClangDataLayoutString()),
       Triple(irgen.getEffectiveClangTriple()), TargetMachine(std::move(target)),
       silConv(irgen.SIL), OutputFilename(OutputFilename),
       MainInputFilenameForDebugInfo(MainInputFilenameForDebugInfo),
@@ -1750,12 +1749,12 @@ llvm::Triple IRGenerator::getEffectiveClangTriple() {
   return llvm::Triple(CI->getTargetInfo().getTargetOpts().Triple);
 }
 
-const llvm::DataLayout &IRGenerator::getClangDataLayout() {
+const llvm::StringRef IRGenerator::getClangDataLayoutString() {
   return static_cast<ClangImporter *>(
              SIL.getASTContext().getClangModuleLoader())
       ->getTargetInfo()
-      .getDataLayout();
-  }
+      .getDataLayoutString();
+}
 
 TypeExpansionContext IRGenModule::getMaximalTypeExpansionContext() const {
   return TypeExpansionContext::maximal(getSwiftModule(),

lib/IRGen/IRGenModule.h

@@ -519,7 +519,7 @@ class IRGenerator {
   /// Return the effective triple used by clang.
   llvm::Triple getEffectiveClangTriple();
 
-  const llvm::DataLayout &getClangDataLayout();
+  const llvm::StringRef getClangDataLayoutString();
 };
 
 class ConstantReference {