[llvm] [BOLT] Fix debug line emission for functions in multiple compilation units (PR #151230)

[Maksim Panchenko via llvm-commits]

================
@@ -852,6 +832,86 @@ class DwarfLineTable {
   // Returns DWARF Version for this line table.
   uint16_t getDwarfVersion() const { return DwarfVersion; }
 };
+
+/// ClusteredRows represents a collection of debug line table row references.
+///
+/// MEMORY LAYOUT AND DESIGN:
----------------
maksfb wrote:

Thanks, @grigorypas! Did you measure build time and memory consumption before/after the change?

https://github.com/llvm/llvm-project/pull/151230