[ODRHash diagnostics] Move common code for calculating diag locations in `DiagnoseODRMismatch` into a lambda. NFC.

[ChuanqiXu]

LGTM with comments.

clang/lib/Serialization/ASTReader.cpp

10020

DiffType is not necessary here, right?

[vsapsai]

Thanks for the review!

clang/lib/Serialization/ASTReader.cpp

10020

Unfortunately, it is necessary. A little bit later we have

if (DiffType == EndOfClass && Tag)

where we use DiffType.

By the way, the implementation isn't really correct for EndOfClass and non-TagDecl as Loc remains invalid. But that's a separate issue, I've decided to keep the current change to NFC.

[ChuanqiXu]

clang/lib/Serialization/ASTReader.cpp

10020

Oh, sorry for I missed that. Thanks!

clang/lib/Serialization/ASTReader.cpp

Diag(SecondRecord->getLocation(),
         << SecondModule;
 
     if (DR.SecondDecl) {
       Diag(DR.SecondDecl->getLocation(), diag::note_second_module_difference)
           << DR.SecondDecl->getSourceRange();
     }
   };
 
-  auto DiagnoseODRMismatch =
-      [this](DiffResult &DR, NamedDecl *FirstRecord, StringRef FirstModule,
-             NamedDecl *SecondRecord, StringRef SecondModule) {
-        SourceLocation FirstLoc;
-        SourceRange FirstRange;
-        auto *FirstTag = dyn_cast<TagDecl>(FirstRecord);
-        if (DR.FirstDiffType == EndOfClass && FirstTag) {
-          FirstLoc = FirstTag->getBraceRange().getEnd();
-        } else {
-          FirstLoc = DR.FirstDecl->getLocation();
-          FirstRange = DR.FirstDecl->getSourceRange();
-        }
-        Diag(FirstLoc, diag::err_module_odr_violation_mismatch_decl)
-            << FirstRecord << FirstModule.empty() << FirstModule << FirstRange
-            << DR.FirstDiffType;
-
-        SourceLocation SecondLoc;
-        SourceRange SecondRange;
-        auto *SecondTag = dyn_cast<TagDecl>(SecondRecord);
-        if (DR.SecondDiffType == EndOfClass && SecondTag) {
-          SecondLoc = SecondTag->getBraceRange().getEnd();
-        } else {
-          SecondLoc = DR.SecondDecl->getLocation();
-          SecondRange = DR.SecondDecl->getSourceRange();
-        }
-        Diag(SecondLoc, diag::note_module_odr_violation_mismatch_decl)
-            << SecondModule << SecondRange << DR.SecondDiffType;
-      };
+  auto DiagnoseODRMismatch = [this](DiffResult &DR, NamedDecl *FirstRecord,
+                                    StringRef FirstModule,
+                                    NamedDecl *SecondRecord,
+                                    StringRef SecondModule) {
+    auto GetMismatchedDeclLoc = [](const NamedDecl *Container,
+                                   ODRMismatchDecl DiffType, const Decl *D) {
+      SourceLocation Loc;
+      SourceRange Range;
+      auto *Tag = dyn_cast<TagDecl>(Container);
+      if (DiffType == EndOfClass && Tag) {
+        Loc = Tag->getBraceRange().getEnd();
+        Loc = D->getLocation();
+        Range = D->getSourceRange();
+      return std::make_pair(Loc, Range);
+    };
+
+    auto FirstDiagInfo =
+        GetMismatchedDeclLoc(FirstRecord, DR.FirstDiffType, DR.FirstDecl);
+    Diag(FirstDiagInfo.first, diag::err_module_odr_violation_mismatch_decl)
+        << FirstRecord << FirstModule.empty() << FirstModule
+        << FirstDiagInfo.second << DR.FirstDiffType;
+
+    auto SecondDiagInfo =
+        GetMismatchedDeclLoc(SecondRecord, DR.SecondDiffType, DR.SecondDecl);
+    Diag(SecondDiagInfo.first, diag::note_module_odr_violation_mismatch_decl)
+        << SecondModule << SecondDiagInfo.second << DR.SecondDiffType;
 
   // Issue any pending ODR-failure diagnostics.
   for (auto &Merge : OdrMergeFailures) {
     // If we've already pointed out a specific problem with this class, don't
     // bother issuing a general "something's different" diagnostic.
     if (!DiagnosedOdrMergeFailures.insert(Merge.first).second)
       continue;