[lldb] Only set the executable module for a target once

Summary:

When we try to find the executable module for our target we don't check
if we already have an executable module set. This causes that when debugging
a program that dlopens another executable, LLDB will take that other executable
as the new executable of the target (which causes that future launches of the
target will launch the dlopen'd executable instead of the original executable).

This just adds a check that we only set the executable when we haven't already
found one.

Fixes rdar://63443099

Reviewers: jasonmolenda, jingham, teemperor

Reviewed By: jasonmolenda, teemperor

Subscribers: jingham, JDevlieghere

Differential Revision: https://reviews.llvm.org/D80724

5 files changed, 63 insertions, 1 deletions

diff --git a/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderDarwin.cpp b/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderDarwin.cpp
index 7310043..569d84d 100644
--- a/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderDarwin.cpp
+++ b/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderDarwin.cpp
@@ -577,7 +577,8 @@ void DynamicLoaderDarwin::UpdateSpecialBinariesFromNewImageInfos(
     }
   }
 
-  if (exe_idx != UINT32_MAX) {
+  // Set the target executable if we haven't found one so far.
+  if (exe_idx != UINT32_MAX && !target.GetExecutableModule()) {
     const bool can_create = true;
     ModuleSP exe_module_sp(FindTargetModuleForImageInfo(image_infos[exe_idx],
                                                         can_create, nullptr));
diff --git a/lldb/test/API/functionalities/dlopen_other_executable/Makefile b/lldb/test/API/functionalities/dlopen_other_executable/Makefile
new file mode 100644
index 0000000..113b9fd
--- /dev/null
+++ b/lldb/test/API/functionalities/dlopen_other_executable/Makefile
@@ -0,0 +1,8 @@
+C_SOURCES := main.c
+USE_LIBDL := 1
+
+other:
+	$(MAKE) -f $(MAKEFILE_RULES) C_SOURCES=other.c EXE=other
+all: other
+
+include Makefile.rules
diff --git a/lldb/test/API/functionalities/dlopen_other_executable/TestDlopenOtherExecutable.py b/lldb/test/API/functionalities/dlopen_other_executable/TestDlopenOtherExecutable.py
new file mode 100644
index 0000000..2ccfaea
--- /dev/null
+++ b/lldb/test/API/functionalities/dlopen_other_executable/TestDlopenOtherExecutable.py
@@ -0,0 +1,42 @@
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+class TestCase(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    @skipIfRemote
+    @skipIfWindows
+    # glibc's dlopen doesn't support opening executables.
+    # https://sourceware.org/bugzilla/show_bug.cgi?id=11754
+    @skipIfLinux
+    @no_debug_info_test
+    def test(self):
+        self.build()
+        # Launch and stop before the dlopen call.
+        lldbutil.run_to_source_breakpoint(self, "// break here", lldb.SBFileSpec("main.c"))
+
+        # Delete the breakpoint we no longer need.
+        self.target().DeleteAllBreakpoints()
+
+        # Check that the executable is the test binary.
+        self.assertEqual(self.target().GetExecutable().GetFilename(), "a.out")
+
+        # Continue so that dlopen is called.
+        breakpoint = self.target().BreakpointCreateBySourceRegex(
+            "// break after dlopen", lldb.SBFileSpec("main.c"))
+        self.assertNotEqual(breakpoint.GetNumResolvedLocations(), 0)
+        stopped_threads = lldbutil.continue_to_breakpoint(self.process(), breakpoint)
+        self.assertEqual(len(stopped_threads), 1)
+
+        # Check that the executable is still the test binary and not "other".
+        self.assertEqual(self.target().GetExecutable().GetFilename(), "a.out")
+
+        # Kill the process and run the program again.
+        err = self.process().Kill()
+        self.assertTrue(err.Success(), str(err))
+
+        # Test that we hit the breakpoint after dlopen.
+        lldbutil.run_to_breakpoint_do_run(self, self.target(), breakpoint)
diff --git a/lldb/test/API/functionalities/dlopen_other_executable/main.c b/lldb/test/API/functionalities/dlopen_other_executable/main.c
new file mode 100644
index 0000000..8f21e86
--- /dev/null
+++ b/lldb/test/API/functionalities/dlopen_other_executable/main.c
@@ -0,0 +1,10 @@
+#include <dlfcn.h>
+#include <assert.h>
+
+int main() {
+  int i = 0; // break here
+  // dlopen the 'other' test executable.
+  int h = dlopen("other", RTLD_LAZY);
+  assert(h && "dlopen failed?");
+  return i; // break after dlopen
+}
diff --git a/lldb/test/API/functionalities/dlopen_other_executable/other.c b/lldb/test/API/functionalities/dlopen_other_executable/other.c
new file mode 100644
index 0000000..237c8ce
--- /dev/null
+++ b/lldb/test/API/functionalities/dlopen_other_executable/other.c
@@ -0,0 +1 @@
+int main() {}