[lldb/API] Add ability to check if module is backed by a file on disk

[mib]

Summary

This patch introduces a new SBAPI method: SBModule::IsFileBacked

As the name suggests, it tells the user if the module's object file is
on disk or in memory.

rdar://68538278

Signed-off-by: Med Ismail Bennani <[e-mail]>

[JDevlieghere]

LGTM

[mib]

As discussed with @jingham offline, it's less ambiguous to rename this to IsFileBacked since it's not the module that does the reading.

lldb/bindings/interface/SBModule.i

public:
     bool
     IsValid () const;
 
     explicit operator bool() const;
 
     void
     Clear();
 
+    %feature("docstring", "Check if the module is file backed.
+    @return
+        True, if the module is backed by an object file on disk.
+        False, if the module is backed by an object file in memory.") IsFileBacked;
+    bool
+    IsFileBacked() const;
+
     %feature("docstring", "
     Get const accessor for the module file specification.
 
     This function returns the file for the module on the host system
     that is running LLDB. This can differ from the path on the
     platform since we might be doing remote debugging.
 
     @return

lldb/include/lldb/API/SBModule.h

public:
   ~SBModule();
 
   explicit operator bool() const;
 
   bool IsValid() const;
 
   void Clear();
 
+  bool IsFileBacked() const;
+
   /// Get const accessor for the module file specification.
   ///
   /// This function returns the file for the module on the host system
   /// that is running LLDB. This can differ from the path on the
   /// platform since we might be doing remote debugging.
   ///
   /// \return
   ///     A const reference to the file specification object.

lldb/source/API/SBModule.cpp

 }
 
 void SBModule::Clear() {
   LLDB_INSTRUMENT_VA(this);
 
   m_opaque_sp.reset();
 }
 
+bool SBModule::IsFileBacked() const {
+  LLDB_INSTRUMENT_VA(this);
+
+  ModuleSP module_sp(GetSP());
+  if (!module_sp)
+    return false;
+
+  ObjectFile *obj_file = module_sp->GetObjectFile();
+  if (!obj_file)
+    return false;
+
+  return !obj_file->IsInMemory();
+}
+
 SBFileSpec SBModule::GetFileSpec() const {
   LLDB_INSTRUMENT_VA(this);
 
   SBFileSpec file_spec;
   ModuleSP module_sp(GetSP());
   if (module_sp)
     file_spec.SetFileSpec(module_sp->GetFileSpec());
 

lldb/test/API/python_api/sbmodule/Makefile

+C_SOURCES := main.c
+
+include Makefile.rules

lldb/test/API/python_api/sbmodule/TestSBModule.py

+"""Test the SBDModule APIs."""
+
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+import os, signal, subprocess
+
+class SBModuleAPICase(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    def setUp(self):
+        TestBase.setUp(self)
+        self.background_pid = None
+
+    def tearDown(self):
+        TestBase.tearDown(self)
+        if self.background_pid:
+            os.kill(self.background_pid, signal.SIGKILL)
+
+
+    def test_module_is_file_backed(self):
+        """Test the SBModule::IsFileBacked() method"""
+        self.build()
+        target, _, _, _  = lldbutil.run_to_source_breakpoint(self, "// break here",
+                                                    lldb.SBFileSpec("main.c"))
+
+        self.assertGreater(target.GetNumModules(), 0)
+        main_module = target.GetModuleAtIndex(0)
+        self.assertEqual(main_module.GetFileSpec().GetFilename(), "a.out")
+        self.assertTrue(main_module.IsFileBacked(),
+                         "The module should be backed by a file on disk")
+
+        self.dbg.DeleteTarget(target)
+        self.assertEqual(self.dbg.GetNumTargets(), 0)
+
+        exe = self.getBuildArtifact("a.out")
+        background_process = subprocess.Popen([exe])
+        self.assertTrue(background_process, "process is not valid")
+        self.background_pid = background_process.pid
+        os.unlink(exe)
+
+        target = self.dbg.CreateTarget('')
+        self.assertEqual(self.dbg.GetNumTargets(), 1)
+        error = lldb.SBError()
+        process = target.AttachToProcessWithID(self.dbg.GetListener(),
+                                               self.background_pid, error)
+        self.assertTrue(error.Success() and process,  PROCESS_IS_VALID)
+        main_module = target.GetModuleAtIndex(0)
+        self.assertEqual(main_module.GetFileSpec().GetFilename(), "a.out")
+        self.assertFalse(main_module.IsFileBacked(),
+                         "The module should not be backed by a file on disk.")
+
+        error = process.Destroy()
+        self.assertTrue(error.Success(), "couldn't destroy process %s" % background_process.pid)
+

lldb/test/API/python_api/sbmodule/main.c

+int main() {
+  while (1) // break here
+    ;
+  return 42;
+}