[llvm] [lldb] DEBUGINFOD based DWP acquisition for LLDB (PR #70996)

[Daniel Thornburgh via llvm-commits]

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@@ -396,8 +398,22 @@ Symbols::LocateExecutableSymbolFile(const ModuleSpec &module_spec,
       }
     }
   }
-
-  return LocateExecutableSymbolFileDsym(module_spec);
+  FileSpec dsym_bundle = LocateExecutableSymbolFileDsym(module_spec);
+  if (dsym_bundle)
+    return dsym_bundle;
+
+  // If we didn't find anything by looking locally, let's try Debuginfod.
+  if (module_uuid.IsValid() && llvm::canUseDebuginfod()) {
+    llvm::object::BuildID build_id(module_uuid.GetBytes());
+    llvm::Expected<std::string> result =
+        llvm::getCachedOrDownloadDebuginfo(build_id);
+    if (result)
+      return FileSpec(*result);
+    // An error is just fine, here...
+    consumeError(result.takeError());
----------------
mysterymath wrote:

> @mysterymath that environment variable is used by the server, not the client.
Ah, I should have linked to the debuginfod-find man page instead; pardon my laziness. It is used by the client, it's just that the server also includes a client for federation purposes.

See https://sourceware.org/git/?p=elfutils.git;a=blob;f=debuginfod/debuginfod-client.c;h=dcf0503163fd73e126a2197d278f363fd6839810;hb=HEAD#l1881

https://github.com/llvm/llvm-project/pull/70996