[CodeGen] Use StringRef. NFC.

Looks like CurFn's name outlives FunctionName, so we can just pass
StringRefs around rather than going from a StringRef to a std::string
to a const char* to a StringRef.

llvm-svn: 285873
diff --git a/clang/lib/CodeGen/CGBlocks.cpp b/clang/lib/CodeGen/CGBlocks.cpp
index 933cd2a..a9a0dea 100644
--- a/clang/lib/CodeGen/CGBlocks.cpp
+++ b/clang/lib/CodeGen/CGBlocks.cpp
@@ -1052,10 +1052,10 @@
 }
 
 llvm::Constant *
-CodeGenModule::GetAddrOfGlobalBlock(const BlockExpr *blockExpr,
-                                    const char *name) {
-  CGBlockInfo blockInfo(blockExpr->getBlockDecl(), name);
-  blockInfo.BlockExpression = blockExpr;
+CodeGenModule::GetAddrOfGlobalBlock(const BlockExpr *BE,
+                                    StringRef Name) {
+  CGBlockInfo blockInfo(BE->getBlockDecl(), Name);
+  blockInfo.BlockExpression = BE;
 
   // Compute information about the layout, etc., of this block.
   computeBlockInfo(*this, nullptr, blockInfo);