[Lldb-commits] [lldb] Add a test for evicting unreachable modules from the global module cache (PR #74894)

via lldb-commits lldb-commits at lists.llvm.org
Tue Dec 12 11:26:42 PST 2023


https://github.com/jimingham updated https://github.com/llvm/llvm-project/pull/74894

>From 438d35a7a7fca454718062583f91776ca018b2b1 Mon Sep 17 00:00:00 2001
From: Jim Ingham <jingham at apple.com>
Date: Fri, 8 Dec 2023 14:43:14 -0800
Subject: [PATCH 1/4] Add a test for evicting unreachable modules from the
 global module cache.

---
 .../python_api/global_module_cache/Makefile   |   1 +
 .../TestGlobalModuleCache.py                  | 110 ++++++++++++++++++
 .../global_module_cache/one-print.c           |   8 ++
 .../global_module_cache/two-print.c           |   9 ++
 4 files changed, 128 insertions(+)
 create mode 100644 lldb/test/API/python_api/global_module_cache/Makefile
 create mode 100644 lldb/test/API/python_api/global_module_cache/TestGlobalModuleCache.py
 create mode 100644 lldb/test/API/python_api/global_module_cache/one-print.c
 create mode 100644 lldb/test/API/python_api/global_module_cache/two-print.c

diff --git a/lldb/test/API/python_api/global_module_cache/Makefile b/lldb/test/API/python_api/global_module_cache/Makefile
new file mode 100644
index 00000000000000..22f1051530f871
--- /dev/null
+++ b/lldb/test/API/python_api/global_module_cache/Makefile
@@ -0,0 +1 @@
+include Makefile.rules
diff --git a/lldb/test/API/python_api/global_module_cache/TestGlobalModuleCache.py b/lldb/test/API/python_api/global_module_cache/TestGlobalModuleCache.py
new file mode 100644
index 00000000000000..ff74d09a128183
--- /dev/null
+++ b/lldb/test/API/python_api/global_module_cache/TestGlobalModuleCache.py
@@ -0,0 +1,110 @@
+"""
+Test the use of the global module cache in lldb
+"""
+
+import lldb
+
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+import os
+import shutil
+from pathlib import Path
+import time
+
+
+class GlobalModuleCacheTestCase(TestBase):
+    # NO_DEBUG_INFO_TESTCASE = True
+
+    def check_counter_var(self, thread, value):
+        frame = thread.frames[0]
+        var = frame.FindVariable("counter")
+        self.assertTrue(var.GetError().Success(), "Got counter variable")
+        self.assertEqual(var.GetValueAsUnsigned(), value, "This was one-print")
+
+    def copy_to_main(self, src, dst):
+        # We are relying on the source file being newer than the .o file from
+        # a previous build, so sleep a bit here to ensure that the touch is later.
+        time.sleep(2)
+        try:
+            shutil.copy(src, dst)
+        except:
+            self.fail(f"Could not copy {src} to {dst}")
+        Path(dst).touch()
+
+    # The rerun tests indicate rerunning on Windows doesn't really work, so
+    # this one won't either.
+    @skipIfWindows
+    def test_OneTargetOneDebugger(self):
+        # Make sure that if we have one target, and we run, then
+        # change the binary and rerun, the binary (and any .o files
+        # if using dwarf in .o file debugging) get removed from the
+        # shared module cache.  They are no longer reachable.
+        debug_style = self.getDebugInfo()
+
+        # Before we do anything, clear the global module cache so we don't
+        # see objects from other runs:
+        lldb.SBDebugger.MemoryPressureDetected()
+
+        # Set up the paths for our two versions of main.c:
+        main_c_path = os.path.join(self.getBuildDir(), "main.c")
+        one_print_path = os.path.join(self.getSourceDir(), "one-print.c")
+        two_print_path = os.path.join(self.getSourceDir(), "two-print.c")
+        main_filespec = lldb.SBFileSpec(main_c_path)
+
+        # First copy the one-print.c to main.c in the build folder and
+        # build our a.out from there:
+        self.copy_to_main(one_print_path, main_c_path)
+        self.build(dictionary={"C_SOURCES": main_c_path, "EXE": "a.out"})
+
+        (target, process, thread, bkpt) = lldbutil.run_to_source_breakpoint(
+            self, "return counter;", main_filespec
+        )
+
+        # Make sure we ran the version we intended here:
+        self.check_counter_var(thread, 1)
+        process.Kill()
+
+        # Now copy two-print.c over main.c, rebuild, and rerun:
+        # os.unlink(target.GetExecutable().fullpath)
+        self.copy_to_main(two_print_path, main_c_path)
+
+        self.build(dictionary={"C_SOURCES": main_c_path, "EXE": "a.out"})
+        error = lldb.SBError()
+        (_, process, thread, _) = lldbutil.run_to_breakpoint_do_run(self, target, bkpt)
+        # In two-print.c counter will be 2:
+        self.check_counter_var(thread, 2)
+
+        num_a_dot_out_entries = 1
+        # For dSYM's there will be two lines of output, one for the a.out and one
+        # for the dSYM.
+        if debug_style == "dsym":
+            num_a_dot_out_entries += 1
+
+        self.check_image_list_result(num_a_dot_out_entries, 1)
+
+    def check_image_list_result(self, num_a_dot_out, num_main_dot_o):
+        # Now look at the global module list, there should only be one a.out, and if we are
+        # doing dwarf in .o file, there should only be one .o file:
+        image_cmd_result = lldb.SBCommandReturnObject()
+        interp = self.dbg.GetCommandInterpreter()
+        interp.HandleCommand("image list -g", image_cmd_result)
+        image_list_str = image_cmd_result.GetOutput()
+        image_list = image_list_str.splitlines()
+        found_a_dot_out = 0
+        found_main_dot_o = 0
+
+        for line in image_list:
+            # FIXME: force this to be at the end of the string:
+            if "a.out" in line:
+                found_a_dot_out += 1
+            if "main.o" in line:
+                found_main_dot_o += 1
+
+        self.assertEqual(
+            num_a_dot_out, found_a_dot_out, "Got the right number of a.out's"
+        )
+        if found_main_dot_o > 0:
+            self.assertEqual(
+                num_main_dot_o, found_main_dot_o, "Got the right number of main.o's"
+            )
diff --git a/lldb/test/API/python_api/global_module_cache/one-print.c b/lldb/test/API/python_api/global_module_cache/one-print.c
new file mode 100644
index 00000000000000..5a572ca7c65fec
--- /dev/null
+++ b/lldb/test/API/python_api/global_module_cache/one-print.c
@@ -0,0 +1,8 @@
+#include <stdio.h>
+
+int
+main() {
+  int counter = 0;
+  printf("I only print one time: %d.\n", counter++);
+  return counter;
+}
diff --git a/lldb/test/API/python_api/global_module_cache/two-print.c b/lldb/test/API/python_api/global_module_cache/two-print.c
new file mode 100644
index 00000000000000..ce6cb84c5c46eb
--- /dev/null
+++ b/lldb/test/API/python_api/global_module_cache/two-print.c
@@ -0,0 +1,9 @@
+#include <stdio.h>
+
+int
+main() {
+  int counter = 0;
+  printf("I print one time: %d.\n", counter++);
+  printf("I print two times: %d.\n", counter++);
+  return counter;
+}

>From 684cee4a363c87c6b2cfa0776adb7c5923a0f6b6 Mon Sep 17 00:00:00 2001
From: Jim Ingham <jingham at apple.com>
Date: Mon, 11 Dec 2023 15:54:38 -0800
Subject: [PATCH 2/4] Add a test for one target with the old file and one with
 the new.

---
 .../TestGlobalModuleCache.py                  | 22 +++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/lldb/test/API/python_api/global_module_cache/TestGlobalModuleCache.py b/lldb/test/API/python_api/global_module_cache/TestGlobalModuleCache.py
index ff74d09a128183..db84c5a2d24d3d 100644
--- a/lldb/test/API/python_api/global_module_cache/TestGlobalModuleCache.py
+++ b/lldb/test/API/python_api/global_module_cache/TestGlobalModuleCache.py
@@ -36,6 +36,13 @@ def copy_to_main(self, src, dst):
     # this one won't either.
     @skipIfWindows
     def test_OneTargetOneDebugger(self):
+        self.do_test_one_debugger(True)
+
+    @expectedFailureAll
+    def test_TwoTargetsOneDebugger(self):
+        self.do_test_one_debugger(False)
+        
+    def do_test_one_debugger(self, one_target):
         # Make sure that if we have one target, and we run, then
         # change the binary and rerun, the binary (and any .o files
         # if using dwarf in .o file debugging) get removed from the
@@ -71,10 +78,21 @@ def test_OneTargetOneDebugger(self):
 
         self.build(dictionary={"C_SOURCES": main_c_path, "EXE": "a.out"})
         error = lldb.SBError()
-        (_, process, thread, _) = lldbutil.run_to_breakpoint_do_run(self, target, bkpt)
+        if one_target:
+            (_, process, thread, _) = lldbutil.run_to_breakpoint_do_run(self, target, bkpt)
+        else:
+            (target2, process2, thread, bkpt) = lldbutil.run_to_source_breakpoint(
+                self, "return counter;", main_filespec
+            )
+
         # In two-print.c counter will be 2:
         self.check_counter_var(thread, 2)
 
+        # If we made two targets, destroy the first one, that should free up the
+        # unreachable Modules:
+        if not one_target:
+            target.Clear()
+
         num_a_dot_out_entries = 1
         # For dSYM's there will be two lines of output, one for the a.out and one
         # for the dSYM.
@@ -82,7 +100,7 @@ def test_OneTargetOneDebugger(self):
             num_a_dot_out_entries += 1
 
         self.check_image_list_result(num_a_dot_out_entries, 1)
-
+        
     def check_image_list_result(self, num_a_dot_out, num_main_dot_o):
         # Now look at the global module list, there should only be one a.out, and if we are
         # doing dwarf in .o file, there should only be one .o file:

>From 09269171e2ab3b1502ff8c25ba67dfcf72b9e509 Mon Sep 17 00:00:00 2001
From: Jim Ingham <jingham at apple.com>
Date: Mon, 11 Dec 2023 16:50:33 -0800
Subject: [PATCH 3/4] Added a test for two debuggers, one target each.  It also
 fails.

---
 .../TestGlobalModuleCache.py                  | 82 ++++++++++++++-----
 1 file changed, 63 insertions(+), 19 deletions(-)

diff --git a/lldb/test/API/python_api/global_module_cache/TestGlobalModuleCache.py b/lldb/test/API/python_api/global_module_cache/TestGlobalModuleCache.py
index db84c5a2d24d3d..d2c388b534cd6f 100644
--- a/lldb/test/API/python_api/global_module_cache/TestGlobalModuleCache.py
+++ b/lldb/test/API/python_api/global_module_cache/TestGlobalModuleCache.py
@@ -36,13 +36,22 @@ def copy_to_main(self, src, dst):
     # this one won't either.
     @skipIfWindows
     def test_OneTargetOneDebugger(self):
-        self.do_test_one_debugger(True)
+        self.do_test(True, True)
 
+    # This behaves as implemented but that behavior is not desirable.
+    # This test tests for the desired behavior as an expected fail.
+    @skipIfWindows
     @expectedFailureAll
     def test_TwoTargetsOneDebugger(self):
-        self.do_test_one_debugger(False)
-        
-    def do_test_one_debugger(self, one_target):
+        self.do_test(False, True)
+
+    @skipIfWindows
+    @expectedFailureAll
+    def test_OneTargetTwoDebuggers(self):
+        self.do_test(True, False)
+
+
+    def do_test(self, one_target, one_debugger):
         # Make sure that if we have one target, and we run, then
         # change the binary and rerun, the binary (and any .o files
         # if using dwarf in .o file debugging) get removed from the
@@ -78,12 +87,29 @@ def do_test_one_debugger(self, one_target):
 
         self.build(dictionary={"C_SOURCES": main_c_path, "EXE": "a.out"})
         error = lldb.SBError()
-        if one_target:
-            (_, process, thread, _) = lldbutil.run_to_breakpoint_do_run(self, target, bkpt)
+        if one_debugger:
+            if one_target:
+                (_, process, thread, _) = lldbutil.run_to_breakpoint_do_run(
+                    self, target, bkpt
+                )
+            else:
+                (target2, process2, thread, bkpt) = lldbutil.run_to_source_breakpoint(
+                    self, "return counter;", main_filespec
+                )
         else:
-            (target2, process2, thread, bkpt) = lldbutil.run_to_source_breakpoint(
-                self, "return counter;", main_filespec
-            )
+            if one_target:
+                new_debugger = lldb.SBDebugger().Create()
+                self.old_debugger = self.dbg
+                self.dbg = new_debugger
+                def cleanupDebugger(self):
+                    lldb.SBDebugger.Destroy(self.dbg)
+                    self.dbg = self.old_debugger
+                    self.old_debugger = None
+
+                self.addTearDownHook(cleanupDebugger)
+                (target2, process2, thread, bkpt) = lldbutil.run_to_source_breakpoint(
+                    self, "return counter;", main_filespec
+                )
 
         # In two-print.c counter will be 2:
         self.check_counter_var(thread, 2)
@@ -99,14 +125,31 @@ def do_test_one_debugger(self, one_target):
         if debug_style == "dsym":
             num_a_dot_out_entries += 1
 
-        self.check_image_list_result(num_a_dot_out_entries, 1)
+        error = self.check_image_list_result(num_a_dot_out_entries, 1)
+        # Even if this fails, MemoryPressureDetected should fix this.
+        lldb.SBDebugger.MemoryPressureDetected()
+        error_after_mpd = self.check_image_list_result(num_a_dot_out_entries, 1)
+        fail_msg = ""
+        if error != "":
+            fail_msg = "Error before MPD: " + error
+            
+        if error_after_mpd != "":
+            fail_msg = fail_msg + "\nError after MPD: " + error_after_mpd
+        if fail_msg != "":
+            self.fail(fail_msg)
         
     def check_image_list_result(self, num_a_dot_out, num_main_dot_o):
-        # Now look at the global module list, there should only be one a.out, and if we are
-        # doing dwarf in .o file, there should only be one .o file:
+        # Check the global module list, there should only be one a.out, and if we are
+        # doing dwarf in .o file, there should only be one .o file.  This returns
+        # an error string on error - rather than asserting, so you can stage this
+        # failing.
         image_cmd_result = lldb.SBCommandReturnObject()
         interp = self.dbg.GetCommandInterpreter()
         interp.HandleCommand("image list -g", image_cmd_result)
+        if self.TraceOn():
+            print(f"Expected: a.out: {num_a_dot_out} main.o: {num_main_dot_o}")
+            print(image_cmd_result)
+
         image_list_str = image_cmd_result.GetOutput()
         image_list = image_list_str.splitlines()
         found_a_dot_out = 0
@@ -119,10 +162,11 @@ def check_image_list_result(self, num_a_dot_out, num_main_dot_o):
             if "main.o" in line:
                 found_main_dot_o += 1
 
-        self.assertEqual(
-            num_a_dot_out, found_a_dot_out, "Got the right number of a.out's"
-        )
-        if found_main_dot_o > 0:
-            self.assertEqual(
-                num_main_dot_o, found_main_dot_o, "Got the right number of main.o's"
-            )
+        
+        if num_a_dot_out != found_a_dot_out:
+            return f"Got {found_a_dot_out} number of a.out's, expected {num_a_dot_out}"
+            
+        if found_main_dot_o > 0 and num_main_dot_o != found_main_dot_o:
+            return f"Got {found_main_dot_o} number of main.o's, expected {num_main_dot_o}"
+        
+        return ""

>From 90119f1d3955029931939d529a9f4b3c113b8284 Mon Sep 17 00:00:00 2001
From: Jim Ingham <jingham at apple.com>
Date: Tue, 12 Dec 2023 11:26:09 -0800
Subject: [PATCH 4/4] busywork

---
 .../global_module_cache/TestGlobalModuleCache.py           | 7 ++-----
 lldb/test/API/python_api/global_module_cache/one-print.c   | 3 +--
 lldb/test/API/python_api/global_module_cache/two-print.c   | 3 +--
 3 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/lldb/test/API/python_api/global_module_cache/TestGlobalModuleCache.py b/lldb/test/API/python_api/global_module_cache/TestGlobalModuleCache.py
index d2c388b534cd6f..98ebdec0404eb4 100644
--- a/lldb/test/API/python_api/global_module_cache/TestGlobalModuleCache.py
+++ b/lldb/test/API/python_api/global_module_cache/TestGlobalModuleCache.py
@@ -12,7 +12,6 @@
 from pathlib import Path
 import time
 
-
 class GlobalModuleCacheTestCase(TestBase):
     # NO_DEBUG_INFO_TESTCASE = True
 
@@ -50,7 +49,6 @@ def test_TwoTargetsOneDebugger(self):
     def test_OneTargetTwoDebuggers(self):
         self.do_test(True, False)
 
-
     def do_test(self, one_target, one_debugger):
         # Make sure that if we have one target, and we run, then
         # change the binary and rerun, the binary (and any .o files
@@ -137,7 +135,7 @@ def cleanupDebugger(self):
             fail_msg = fail_msg + "\nError after MPD: " + error_after_mpd
         if fail_msg != "":
             self.fail(fail_msg)
-        
+
     def check_image_list_result(self, num_a_dot_out, num_main_dot_o):
         # Check the global module list, there should only be one a.out, and if we are
         # doing dwarf in .o file, there should only be one .o file.  This returns
@@ -161,12 +159,11 @@ def check_image_list_result(self, num_a_dot_out, num_main_dot_o):
                 found_a_dot_out += 1
             if "main.o" in line:
                 found_main_dot_o += 1
-
         
         if num_a_dot_out != found_a_dot_out:
             return f"Got {found_a_dot_out} number of a.out's, expected {num_a_dot_out}"
             
         if found_main_dot_o > 0 and num_main_dot_o != found_main_dot_o:
             return f"Got {found_main_dot_o} number of main.o's, expected {num_main_dot_o}"
-        
+
         return ""
diff --git a/lldb/test/API/python_api/global_module_cache/one-print.c b/lldb/test/API/python_api/global_module_cache/one-print.c
index 5a572ca7c65fec..f008f36c2554e4 100644
--- a/lldb/test/API/python_api/global_module_cache/one-print.c
+++ b/lldb/test/API/python_api/global_module_cache/one-print.c
@@ -1,7 +1,6 @@
 #include <stdio.h>
 
-int
-main() {
+int main() {
   int counter = 0;
   printf("I only print one time: %d.\n", counter++);
   return counter;
diff --git a/lldb/test/API/python_api/global_module_cache/two-print.c b/lldb/test/API/python_api/global_module_cache/two-print.c
index ce6cb84c5c46eb..96f68cbed83c60 100644
--- a/lldb/test/API/python_api/global_module_cache/two-print.c
+++ b/lldb/test/API/python_api/global_module_cache/two-print.c
@@ -1,7 +1,6 @@
 #include <stdio.h>
 
-int
-main() {
+int main() {
   int counter = 0;
   printf("I print one time: %d.\n", counter++);
   printf("I print two times: %d.\n", counter++);



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