[lldb] Realpath symlinks for breakpoints (#102223)

Improve the chance of resolving file/line breakpoints by realpath'ing the support files before doing a second match attempt, with some conditions applied.

A working [hello-world example](https://github.com/royitaqi/lldb_demos/blob/main/realpath/README.md).

See [patch](https://github.com/llvm/llvm-project/pull/102223) for more info about problem/motivation, details of the feature, new settings, telemetries and tests.

1 files changed, 11 insertions, 1 deletions

diff --git a/lldb/source/Breakpoint/BreakpointResolverFileLine.cpp b/lldb/source/Breakpoint/BreakpointResolverFileLine.cpp
index 16c4ee1..5087540 100644
--- a/lldb/source/Breakpoint/BreakpointResolverFileLine.cpp
+++ b/lldb/source/Breakpoint/BreakpointResolverFileLine.cpp
@@ -15,6 +15,7 @@
 #include "lldb/Target/Target.h"
 #include "lldb/Utility/LLDBLog.h"
 #include "lldb/Utility/Log.h"
+#include "lldb/Utility/RealpathPrefixes.h"
 #include "lldb/Utility/StreamString.h"
 #include <optional>
 
@@ -290,16 +291,25 @@ Searcher::CallbackReturn BreakpointResolverFileLine::SearchCallback(
   const uint32_t line = m_location_spec.GetLine().value_or(0);
   const std::optional<uint16_t> column = m_location_spec.GetColumn();
 
+  Target &target = GetBreakpoint()->GetTarget();
+  RealpathPrefixes realpath_prefixes = target.GetSourceRealpathPrefixes();
+
   const size_t num_comp_units = context.module_sp->GetNumCompileUnits();
   for (size_t i = 0; i < num_comp_units; i++) {
     CompUnitSP cu_sp(context.module_sp->GetCompileUnitAtIndex(i));
     if (cu_sp) {
       if (filter.CompUnitPasses(*cu_sp))
         cu_sp->ResolveSymbolContext(m_location_spec, eSymbolContextEverything,
-                                    sc_list);
+                                    sc_list, &realpath_prefixes);
     }
   }
 
+  // Gather stats into the Target
+  target.GetStatistics().IncreaseSourceRealpathAttemptCount(
+      realpath_prefixes.GetSourceRealpathAttemptCount());
+  target.GetStatistics().IncreaseSourceRealpathCompatibleCount(
+      realpath_prefixes.GetSourceRealpathCompatibleCount());
+
   FilterContexts(sc_list);
 
   DeduceSourceMapping(sc_list);