Add a testcase for Clang modules being updated within one LLDB session.

This actually works as expected, but wasn't explicitly tested before.

Author: adrian-prantl

lldb/packages/Python/lldbsuite/test/lang/objc/modules-update/Makefile

@@ -0,0 +1,3 @@
+CFLAGS_EXTRAS = -I$(BUILDDIR)
+USE_PRIVATE_MODULE_CACHE = YES
+include Makefile.rules

lldb/packages/Python/lldbsuite/test/lang/objc/modules-update/TestClangModulesUpdate.py

@@ -0,0 +1,69 @@
+from __future__ import print_function
+
+import unittest2
+import os
+import shutil
+
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class TestClangModuleUpdate(TestBase):
+    mydir = TestBase.compute_mydir(__file__)
+
+    def setUp(self):
+        TestBase.setUp(self)
+
+    @skipUnlessDarwin
+    @skipIf(debug_info=no_match(["gmodules"]))
+    def test_expr(self):
+        with open(self.getBuildArtifact("module.modulemap"), "w") as f:
+            f.write("""
+                    module Foo { header "f.h" }
+                    """)
+        with open(self.getBuildArtifact("f.h"), "w") as f:
+            f.write("""
+                    struct Q { int i; };
+                    void f() {}
+                    """)
+
+        mod_cache = self.getBuildArtifact("private-module-cache")
+        if os.path.isdir(mod_cache):
+          shutil.rmtree(mod_cache)
+        d = {'OBJC_SOURCES': 'first.m'}
+        self.build(dictionary=d)
+        self.assertTrue(os.path.isdir(mod_cache), "module cache exists")
+
+        logfile = self.getBuildArtifact("modules.log")
+        self.runCmd("log enable -f %s lldb module" % logfile)
+        target, process, _, bkpt = lldbutil.run_to_name_breakpoint(self, "main")
+        self.assertIn("int i", str(target.FindTypes('Q').GetTypeAtIndex(0)))
+        self.expect("image list -g", patterns=[r'first\.o', r'Foo.*\.pcm'])
+
+        # Update the module.
+        with open(self.getBuildArtifact("f.h"), "w") as f:
+            f.write("""
+                    struct S { int i; };
+                    struct S getS() { struct S r = {1}; return r; }
+                    void f() {}
+                    """)
+
+        # Rebuild.
+        d = {'OBJC_SOURCES': 'second.m'}
+        self.build(dictionary=d)
+
+        # Reattach.
+        process.Kill()
+        target, process, _, _ = lldbutil.run_to_breakpoint_do_run(self, target, bkpt)
+        self.assertIn("int i", str(target.FindTypes('S').GetTypeAtIndex(0)))
+        self.expect("image list -g", patterns=[r'second\.o', r'Foo.*\.pcm'])
+
+        # Check log file.
+        found = False
+        with open(logfile, 'r') as f:
+            for line in f:
+                if "module changed" in line and "Foo" in line:
+                    found = True
+        self.assertTrue(found)

lldb/packages/Python/lldbsuite/test/lang/objc/modules-update/first.m

@@ -0,0 +1,5 @@
+@import Umbrella;
+int main(int argc, char **argv) {
+  f(); // break here
+  return 0;
+}

lldb/packages/Python/lldbsuite/test/lang/objc/modules-update/module.modulemap

@@ -0,0 +1,4 @@
+module Umbrella {
+  header "umbrella.h"
+  export *
+}

lldb/packages/Python/lldbsuite/test/lang/objc/modules-update/second.m

@@ -0,0 +1,5 @@
+@import Umbrella;
+int main() {
+  struct S s = getS(); // break here
+  return s.i;
+}

lldb/packages/Python/lldbsuite/test/lang/objc/modules-update/umbrella.h

@@ -0,0 +1 @@
+@import Foo;

lldb/source/Core/ModuleList.cpp

@@ -752,9 +752,10 @@ Status ModuleList::GetSharedModule(const ModuleSpec &module_spec,
 
           Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_MODULES));
           if (log != nullptr)
-            LLDB_LOGF(log,
-                      "module changed: %p, removing from global module list",
-                      static_cast<void *>(module_sp.get()));
+            LLDB_LOGF(
+                log, "%p '%s' module changed: removing from global module list",
+                static_cast<void *>(module_sp.get()),
+                module_sp->GetFileSpec().GetFilename().GetCString());
 
           shared_module_list.Remove(module_sp);
           module_sp.reset();