[llvm] [GSYM] Add support for querying merged functions in llvm-gsymutil (PR #120991)

[Greg Clayton via llvm-commits]

================
@@ -342,6 +342,41 @@ llvm::Expected<LookupResult> GsymReader::lookup(uint64_t Addr) const {
     return ExpectedData.takeError();
 }
 
+llvm::Expected<std::vector<LookupResult>>
+GsymReader::lookupAll(uint64_t Addr) const {
+  std::vector<LookupResult> Results;
+
+  // First perform a lookup to get the primary function info result
+  auto MainResult = lookup(Addr);
+  if (!MainResult)
+    return MainResult.takeError();
+
+  // Add the main result as the first entry
----------------
clayborg wrote:

Add something like:
```
// If a top level FunctionInfo has merged functions, the top level entry and the merged function infos need to be added to the results.
```

https://github.com/llvm/llvm-project/pull/120991