[lld] [llvm] [Symbolizer] Support for Missing Line Numbers. (PR #82240)

[David Blaikie via llvm-commits]

================
@@ -1312,23 +1312,27 @@ uint32_t DWARFDebugLine::LineTable::findRowInSeq(
   return RowPos - Rows.begin();
 }
 
-uint32_t DWARFDebugLine::LineTable::lookupAddress(
-    object::SectionedAddress Address) const {
+uint32_t
+DWARFDebugLine::LineTable::lookupAddress(object::SectionedAddress Address,
+                                         bool Approximate,
+                                         bool *IsApproximateLine) const {
 
   // Search for relocatable addresses
-  uint32_t Result = lookupAddressImpl(Address);
+  uint32_t Result = lookupAddressImpl(Address, Approximate, IsApproximateLine);
 
   if (Result != UnknownRowIndex ||
       Address.SectionIndex == object::SectionedAddress::UndefSection)
     return Result;
 
   // Search for absolute addresses
   Address.SectionIndex = object::SectionedAddress::UndefSection;
-  return lookupAddressImpl(Address);
+  return lookupAddressImpl(Address, Approximate, IsApproximateLine);
 }
 
-uint32_t DWARFDebugLine::LineTable::lookupAddressImpl(
-    object::SectionedAddress Address) const {
+uint32_t
+DWARFDebugLine::LineTable::lookupAddressImpl(object::SectionedAddress Address,
+                                             bool Approximate,
+                                             bool *IsApproximateLine) const {
----------------
dwblaikie wrote:

This should be one parameter rather than two, I think? (thought we discussed this before, though, so maybe there's a reason it can't be just one)

A non-null IsApproximateLine could be interpreted as a request for approximation, then whether or not approximation was used in the response would be provided via writing through the pointer (true or false as needed).

(the caller up in `getFileLineInfoForAddress` can do this:
```
  uint32_t RowIndex =
      lookupAddress(Address, Approximate ? &Result.IsApproximatedLine : nullptr);
```

https://github.com/llvm/llvm-project/pull/82240