Fix dangling reference to a local std::string.

Bug: 16031597

llvm::StringRefs are just lightweight wrappers around strings, and don't
retain/own any of the storage for the actual underlying string. This causes
lifetime issues if any local std::string objects that are then wrapped by
llvm::StringRef ever escape. When the local object goes out of scope, we are
left with a dangling reference.

Valgrind helped us to catch this happening for constant array exports, which
only ever use a statically named "<ConstantArray>" reference, so we can
simply replace it with static C string (wrapped by llvm::StringRef).

Change-Id: I0a9fae2687bc9f53d091d56cf15f99bb75ca46e4

2 files changed, 2 insertions, 4 deletions

diff --git a/slang_rs_export_type.cpp b/slang_rs_export_type.cpp
index c0ab631..4348ea0 100644
--- a/slang_rs_export_type.cpp
+++ b/slang_rs_export_type.cpp
@@ -744,7 +744,7 @@ llvm::StringRef RSExportType::GetTypeName(const clang::Type* T) {
     }
     case clang::Type::ConstantArray : {
       // Construct name for a constant array is too complicated.
-      return CreateDummyName("ConstantArray", std::string());
+      return "<ConstantArray>";
     }
     default: {
       break;
diff --git a/slang_rs_export_type.h b/slang_rs_export_type.h
index 841a230..afd2db2 100644
--- a/slang_rs_export_type.h
+++ b/slang_rs_export_type.h
@@ -476,9 +476,7 @@ class RSExportConstantArrayType : public RSExportType {
   RSExportConstantArrayType(RSContext *Context,
                             const RSExportType *ElementType,
                             unsigned Size)
-    : RSExportType(Context,
-                   ExportClassConstantArray,
-                   CreateDummyName("ConstantArray", std::string())),
+    : RSExportType(Context, ExportClassConstantArray, "<ConstantArray>"),
       mElementType(ElementType),
       mSize(Size) {
   }