[clang] [clang][index][USR] GenLoc prints file entry at most once, allow repeated offsets (PR #205430)

[Ziqing Luo via cfe-commits]

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@@ -24,6 +24,22 @@ using namespace clang::index;
 // USR generation.
 //===----------------------------------------------------------------------===//
 
+/// Print only the offset part of \p Loc
+/// \returns true on error.
+static bool printLocOffset(llvm::raw_ostream &OS, SourceLocation Loc,
+                           const SourceManager &SM) {
+  if (Loc.isInvalid())
+    return true;
+  Loc = SM.getExpansionLoc(Loc);
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ziqingluo-90 wrote:

You are right. Even though having the same expansion but different spelling locations for decls seems to be a rare case to me, it is worth fixing.

https://github.com/llvm/llvm-project/pull/205430