[LLVMDebugInfoPDB] - Use cantFail() instead of assert().

Currently injected-sources-native.test fails with "Expected<T>
value was in success state.
(Note: Expected<T> values in success mode must still be checked
prior to being destroyed)"
when llvm is compiled with LLVM_ENABLE_ABI_BREAKING_CHECKS in Release.

The problem is that getStringForID returns Expected<StringRef>
and Expected value must always be checked, even if it is in success state.
Checking with assert only helps in Debug and is wrong.

Differential revision: https://reviews.llvm.org/D69251

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@375492 91177308-0d34-0410-b5e6-96231b3b80d8

Author: George Rimar

Diff for: lib/DebugInfo/PDB/Native/NativeEnumInjectedSources.cpp

@@ -46,30 +46,31 @@ class NativeInjectedSource final : public IPDBInjectedSource {
   uint64_t getCodeByteSize() const override { return Entry.FileSize; }
 
   std::string getFileName() const override {
-    auto Name = Strings.getStringForID(Entry.FileNI);
-    assert(Name && "InjectedSourceStream should have rejected this");
-    return *Name;
+    StringRef Ret = cantFail(Strings.getStringForID(Entry.FileNI),
+                             "InjectedSourceStream should have rejected this");
+    return Ret;
   }
 
   std::string getObjectFileName() const override {
-    auto ObjName = Strings.getStringForID(Entry.ObjNI);
-    assert(ObjName && "InjectedSourceStream should have rejected this");
-    return *ObjName;
+    StringRef Ret = cantFail(Strings.getStringForID(Entry.ObjNI),
+                             "InjectedSourceStream should have rejected this");
+    return Ret;
   }
 
   std::string getVirtualFileName() const override {
-    auto VName = Strings.getStringForID(Entry.VFileNI);
-    assert(VName && "InjectedSourceStream should have rejected this");
-    return *VName;
+    StringRef Ret = cantFail(Strings.getStringForID(Entry.VFileNI),
+                             "InjectedSourceStream should have rejected this");
+    return Ret;
   }
 
   uint32_t getCompression() const override { return Entry.Compression; }
 
   std::string getCode() const override {
     // Get name of stream storing the data.
-    auto VName = Strings.getStringForID(Entry.VFileNI);
-    assert(VName && "InjectedSourceStream should have rejected this");
-    std::string StreamName = ("/src/files/" + *VName).str();
+    StringRef VName =
+        cantFail(Strings.getStringForID(Entry.VFileNI),
+                 "InjectedSourceStream should have rejected this");
+    std::string StreamName = ("/src/files/" + VName).str();
 
     // Find stream with that name and read its data.
     // FIXME: Consider validating (or even loading) all this in