[Lldb-commits] [lldb] [LLDB][SBSaveCore] Add Extension to Save a thread and N pointers dead (PR #111601)

Jacob Lalonde via lldb-commits lldb-commits at lists.llvm.org
Tue Oct 8 15:56:15 PDT 2024


https://github.com/Jlalond created https://github.com/llvm/llvm-project/pull/111601

This adds an extension to allow the saving of a Thread and it's pointers N layers deep via BFS. This lets SBSaveCore 'automagically' figure out everything important for a given thread to save on your behalf.

>From b128131f457a013102b2a0b2fcb968956d980076 Mon Sep 17 00:00:00 2001
From: Jacob Lalonde <jalalonde at fb.com>
Date: Tue, 8 Oct 2024 15:52:45 -0700
Subject: [PATCH 1/2] Create new extension for save core to save a thread and N
 pointers deep

---
 .../interface/SBSaveCoreOptionsExtensions.i   | 31 +++++++++++++++++++
 lldb/bindings/interfaces.swig                 |  1 +
 .../TestProcessSaveCoreMinidump.py            | 22 +++++++++++++
 3 files changed, 54 insertions(+)
 create mode 100644 lldb/bindings/interface/SBSaveCoreOptionsExtensions.i

diff --git a/lldb/bindings/interface/SBSaveCoreOptionsExtensions.i b/lldb/bindings/interface/SBSaveCoreOptionsExtensions.i
new file mode 100644
index 00000000000000..668efbf0f932f1
--- /dev/null
+++ b/lldb/bindings/interface/SBSaveCoreOptionsExtensions.i
@@ -0,0 +1,31 @@
+#extend lldb::SBSaveCoreOptions {
+#ifdef SWIGPYTHON
+    %pythoncode% {
+        '''Add a thread to the SaveCoreOptions thread list, and follow it's children N pointers deep, adding each memory region to the SaveCoreOptions Memory region list.'''
+        def save_thread_with_heaps(self, thread, num_heaps_deep = 3):
+            self.AddThread(thread)
+            frame = thread.GetFrameAtIndex(0)
+            process = thread.GetProcess()
+            queue = []
+            for var in frame.locals:
+                if var.TypeIsPointerType():
+                    queue.append(var.Dereference())
+            
+            while (num_heaps_deep > 0 and len(queue) > 0):
+                queue_size = len(queue)
+                for i in range(0, queue_size):
+                    var = queue.pop(0)
+                    memory_region = lldb.SBMemoryRegionInfo()
+                    process.GetMemoryRegionInfo(var.GetAddress().GetOffset(), memory_region)
+                    self.AddMemoryRegionToSave(memory_region)
+                    /* 
+                    We only check for direct pointer children T*, should probably scan 
+                    internal to the children themselves. 
+                    */
+                    for x in var.children:
+                        if x.TypeIsPointerType():
+                            queue.append(x.Dereference())
+
+                num_heaps_deep -= 1
+}
+#endif SWIGPYTHON
diff --git a/lldb/bindings/interfaces.swig b/lldb/bindings/interfaces.swig
index 8a6fed95f0b729..8a82ba28d3f2ae 100644
--- a/lldb/bindings/interfaces.swig
+++ b/lldb/bindings/interfaces.swig
@@ -26,6 +26,7 @@
 %include "./interface/SBCommunicationDocstrings.i"
 %include "./interface/SBCompileUnitDocstrings.i"
 %include "./interface/SBSaveCoreOptionsDocstrings.i"
+#include "./interface/SBSaveCoreOptionsExtensions.i"
 %include "./interface/SBDataDocstrings.i"
 %include "./interface/SBDebuggerDocstrings.i"
 %include "./interface/SBDeclarationDocstrings.i"
diff --git a/lldb/test/API/functionalities/process_save_core_minidump/TestProcessSaveCoreMinidump.py b/lldb/test/API/functionalities/process_save_core_minidump/TestProcessSaveCoreMinidump.py
index 03cc415924e0bb..cb5d625f4bffa4 100644
--- a/lldb/test/API/functionalities/process_save_core_minidump/TestProcessSaveCoreMinidump.py
+++ b/lldb/test/API/functionalities/process_save_core_minidump/TestProcessSaveCoreMinidump.py
@@ -3,6 +3,7 @@
 """
 
 import os
+
 import lldb
 from lldbsuite.test.decorators import *
 from lldbsuite.test.lldbtest import *
@@ -470,6 +471,27 @@ def save_core_with_region(self, process, region_index):
             if os.path.isfile(custom_file):
                 os.unlink(custom_file)
 
+    def save_core_one_thread_one_heap(self, process, region_index):
+        try:
+            custom_file = self.getBuildArtifact("core.one_thread_one_heap.dmp")
+            options = lldb.SBSaveCoreOptions()
+            options.SetOutputFile(lldb.SBFileSpec(custom_file))
+            options.SetPluginName("minidump")
+            options.SetStyle(lldb.eSaveCoreCustomOnly)
+            thread = process.GetThreadAtIndex(0)
+            options.save_thread_with_heaps(thread)
+
+            error = process.SaveCore(options)
+            self.assertTrue(error.Success())
+            core_target = self.dbg.CreateTarget(None)
+            core_proc = core_target.LoadCore(custom_file)
+            # proc/pid maps prevent us from checking the number of regions, but
+            # this is mostly a smoke test for the extension.
+            self.assertEqual(core_proc.GetNumThreads(), 1)
+        finally:
+            if os.path.isfile(custom_file):
+                os.unlink(custom_file)
+
     @skipUnlessArch("x86_64")
     @skipUnlessPlatform(["linux"])
     def test_save_minidump_custom_save_style_duplicated_regions(self):

>From fb88cd1ec39daf00f40b45c324bb1b1bbc56c2d6 Mon Sep 17 00:00:00 2001
From: Jacob Lalonde <jalalonde at fb.com>
Date: Tue, 8 Oct 2024 15:53:19 -0700
Subject: [PATCH 2/2] Reword the variable

---
 lldb/bindings/interface/SBSaveCoreOptionsExtensions.i | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lldb/bindings/interface/SBSaveCoreOptionsExtensions.i b/lldb/bindings/interface/SBSaveCoreOptionsExtensions.i
index 668efbf0f932f1..5d20aacacadad4 100644
--- a/lldb/bindings/interface/SBSaveCoreOptionsExtensions.i
+++ b/lldb/bindings/interface/SBSaveCoreOptionsExtensions.i
@@ -2,7 +2,7 @@
 #ifdef SWIGPYTHON
     %pythoncode% {
         '''Add a thread to the SaveCoreOptions thread list, and follow it's children N pointers deep, adding each memory region to the SaveCoreOptions Memory region list.'''
-        def save_thread_with_heaps(self, thread, num_heaps_deep = 3):
+        def save_thread_with_heaps(self, thread, num_pointers_deep = 3):
             self.AddThread(thread)
             frame = thread.GetFrameAtIndex(0)
             process = thread.GetProcess()
@@ -11,7 +11,7 @@
                 if var.TypeIsPointerType():
                     queue.append(var.Dereference())
             
-            while (num_heaps_deep > 0 and len(queue) > 0):
+            while (num_pointers_deep > 0 and len(queue) > 0):
                 queue_size = len(queue)
                 for i in range(0, queue_size):
                     var = queue.pop(0)
@@ -26,6 +26,6 @@
                         if x.TypeIsPointerType():
                             queue.append(x.Dereference())
 
-                num_heaps_deep -= 1
+                num_pointers_deep -= 1
 }
 #endif SWIGPYTHON



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