[LLDB] Add load core time to target metrics (llvm#161581)

This patch adds a load core time, right now we don't have much insight
into the performance of load core, especially for large coredumps. To
start collecting information on this I've added some minor
instrumentation code to measure the two call sites of `LoadCore`.

I've also added a test to validate the new metric is output in
statistics dump

Author: Jlalond

lldb/include/lldb/Target/Statistics.h

@@ -322,12 +322,14 @@ class TargetStats {
   void IncreaseSourceRealpathCompatibleCount(uint32_t count);
 
   StatsDuration &GetCreateTime() { return m_create_time; }
+  StatsDuration &GetLoadCoreTime() { return m_load_core_time; }
   StatsSuccessFail &GetExpressionStats() { return m_expr_eval; }
   StatsSuccessFail &GetFrameVariableStats() { return m_frame_var; }
   void Reset(Target &target);
 
 protected:
   StatsDuration m_create_time;
+  StatsDuration m_load_core_time;
   std::optional<StatsTimepoint> m_launch_or_attach_time;
   std::optional<StatsTimepoint> m_first_private_stop_time;
   std::optional<StatsTimepoint> m_first_public_stop_time;

lldb/source/API/SBTarget.cpp

@@ -255,6 +255,7 @@ SBProcess SBTarget::LoadCore(const char *core_file, lldb::SBError &error) {
     ProcessSP process_sp(target_sp->CreateProcess(
         target_sp->GetDebugger().GetListener(), "", &filespec, false));
     if (process_sp) {
+      ElapsedTime loadCoreTime(target_sp->GetStatistics().GetLoadCoreTime());
       error.SetError(process_sp->LoadCore());
       if (error.Success())
         sb_process.SetSP(process_sp);

lldb/source/Commands/CommandObjectTarget.cpp

@@ -418,7 +418,11 @@ class CommandObjectTargetCreate : public CommandObjectParsed {
         if (process_sp) {
           // Seems weird that we Launch a core file, but that is what we
           // do!
-          error = process_sp->LoadCore();
+          {
+            ElapsedTime loadCoreTime(
+                target_sp->GetStatistics().GetLoadCoreTime());
+            error = process_sp->LoadCore();
+          }
 
           if (error.Fail()) {
             result.AppendError(error.AsCString("unknown core file format"));

lldb/source/Target/Statistics.cpp

@@ -148,6 +148,11 @@ TargetStats::ToJSON(Target &target,
     target_metrics_json.try_emplace("targetCreateTime",
                                     m_create_time.get().count());
 
+    if (m_load_core_time.get().count() > 0) {
+      target_metrics_json.try_emplace("loadCoreTime",
+                                      m_load_core_time.get().count());
+    }
+
     json::Array breakpoints_array;
     double totalBreakpointResolveTime = 0.0;
     // Report both the normal breakpoint list and the internal breakpoint list.

lldb/test/API/functionalities/stats_api/TestStatisticsAPI.py

@@ -1,6 +1,7 @@
 # Test the SBAPI for GetStatistics()
 
 import json
+
 import lldb
 from lldbsuite.test.decorators import *
 from lldbsuite.test.lldbtest import *
@@ -54,6 +55,11 @@ def test_stats_api(self):
             stats_json,
             'Make sure the "frameVariable" key in in target.GetStatistics()["targets"][0]',
         )
+        self.assertNotIn(
+            "loadCoreTime",
+            stats_json,
+            "LoadCoreTime should not be present in a live, non-coredump target",
+        )
         expressionEvaluation = stats_json["expressionEvaluation"]
         self.assertIn(
             "successes",
@@ -157,3 +163,25 @@ def test_command_stats_force(self):
         stats_force.GetAsJSON(stream_force)
         debug_stats_force = json.loads(stream_force.GetData())
         self.assertEqual(debug_stats_force["totalDebugInfoByteSize"], 445)
+
+    def test_core_load_time(self):
+        """
+        Test to see if the coredump path is included in statistics dump.
+        """
+        yaml_file = "arm64-minidump-build-ids.yaml"
+        src_dir = self.getSourceDir()
+        minidump_path = self.getBuildArtifact(os.path.basename(yaml_file) + ".dmp")
+        self.yaml2obj(os.path.join(src_dir, yaml_file), minidump_path)
+        target = self.dbg.CreateTarget(None)
+        process = target.LoadCore(minidump_path)
+        self.assertTrue(process.IsValid())
+
+        stats_options = lldb.SBStatisticsOptions()
+        stats = target.GetStatistics(stats_options)
+        stream = lldb.SBStream()
+        stats.GetAsJSON(stream)
+        debug_stats = json.loads(stream.GetData())
+        self.assertTrue("targets" in debug_stats)
+        target_info = debug_stats["targets"][0]
+        self.assertTrue("loadCoreTime" in target_info)
+        self.assertTrue(float(target_info["loadCoreTime"]) > 0.0)

lldb/test/API/functionalities/stats_api/arm64-minidump-build-ids.yaml

@@ -0,0 +1,19 @@
+--- !minidump
+Streams:
+  - Type:            SystemInfo
+    Processor Arch:  ARM
+    Platform ID:     Linux
+    CSD Version:     '15E216'
+    CPU:
+      CPUID:           0x00000000
+  - Type:            ModuleList
+    Modules:
+      - Base of Image:   0x0000000000001000
+        Size of Image:   0x00001000
+        Module Name:     '/tmp/a'
+        CodeView Record: 4C4570420102030405060708090A0B0C0D0E0F1011121314
+      - Base of Image:   0x0000000000001000
+        Size of Image:   0x00001000
+        Module Name:     '/tmp/b'
+        CodeView Record: 4C4570420A141E28323C46505A646E78828C96A0AAB4BEC8
+...