[Cherry-pick into next] Register the symbol context's module's AST files first.

lldb/packages/Python/lldbsuite/test/make/Makefile.rules

@@ -837,18 +837,17 @@ DYLIB_SWIFT_FLAGS=  \
         -Xlinker -install_name -Xlinker "$(DYLIB_INSTALL_NAME)" \
         $(LD_EXTRAS)
 ifeq "$(DYLIB_HIDE_SWIFTMODULE)" ""
-DYLIB_SWIFT_FLAGS+= -Xlinker -add_ast_path -Xlinker $(DYLIB_NAME).swiftmodule
+DYLIB_SWIFT_FLAGS+= -Xlinker -add_ast_path -Xlinker $(MODULENAME).swiftmodule
 endif
 else
 DYLIB_SWIFT_FLAGS=$(LD_EXTRAS)
+ifeq "$(DYLIB_HIDE_SWIFTMODULE)" ""
+DYLIB_OBJECTS += $(BUILDDIR)/$(MODULENAME).o
+endif
 endif
+
 $(DYLIB_FILENAME) : $(DYLIB_OBJECTS) $(MODULE_INTERFACE)
 	@echo "### Linking dynamic library $(DYLIB_NAME)"
-ifneq "$(DYLIB_HIDE_SWIFTMODULE)" ""
-	$(SWIFTC) $(patsubst -g,,$(SWIFTFLAGS)) \
-            -emit-library $(DYLIB_SWIFT_FLAGS) -o $@ \
-            $(patsubst %.swiftmodule.o,,$(DYLIB_OBJECTS))
-else
 ifneq "$(FRAMEWORK)" ""
 	mkdir -p $(FRAMEWORK).framework/Versions/A/Headers
 	mkdir -p $(FRAMEWORK).framework/Versions/A/Modules
@@ -865,7 +864,6 @@ endif
 endif
 	$(SWIFTC) $(patsubst -g,,$(SWIFTFLAGS)) \
             -emit-library $(DYLIB_SWIFT_FLAGS) -o $@ $(DYLIB_OBJECTS)
-endif
 ifneq "$(CODESIGN)" ""
 	$(CODESIGN) -s - "$(DYLIB_FILENAME)"
 endif

lldb/source/Plugins/TypeSystem/Swift/SwiftASTContext.cpp

@@ -2979,10 +2979,56 @@ lldb::TypeSystemSP SwiftASTContext::CreateInstance(
                                plugin_search_options.begin(),
                                plugin_search_options.end());
 
+  // Register the symbol context's module first. This makes it more
+  // likely that compatible AST blobs are found first, since then the
+  // local AST blobs overwrite any ones with the same import path from
+  // another dylib.
+  llvm::DenseSet<Module *> visited_modules;
+  llvm::StringMap<ModuleSP> all_modules;
   for (size_t mi = 0; mi != num_images; ++mi) {
-    std::vector<std::string> module_names;
-    auto module_sp = target.GetImages().GetModuleAtIndex(mi);
-    swift_ast_sp->RegisterSectionModules(*module_sp, module_names);
+    auto image_sp = target.GetImages().GetModuleAtIndex(mi);
+    std::string path = image_sp->GetSpecificationDescription();
+    all_modules.insert({path, image_sp});
+    all_modules.insert({llvm::sys::path::filename(path), image_sp});
+  }
+  std::vector<std::string> module_names;
+  std::function<void(ModuleSP, unsigned)> scan_module =
+      [&](ModuleSP cur_module_sp, unsigned indent) {
+        if (!cur_module_sp ||
+            !visited_modules.insert(cur_module_sp.get()).second)
+          return;
+        swift_ast_sp->RegisterSectionModules(*cur_module_sp, module_names);
+        if (GetLog(LLDBLog::Types)) {
+          std::string spacer(indent, '-');
+          LOG_PRINTF(GetLog(LLDBLog::Types), "+%s Dependency scan: %s",
+                     spacer.c_str(),
+                     cur_module_sp->GetSpecificationDescription().c_str());
+        }
+        if (auto object = cur_module_sp->GetObjectFile()) {
+          FileSpecList file_list;
+          object->GetDependentModules(file_list);
+          for (auto &fs : file_list) {
+            if (ModuleSP dependency = all_modules.lookup(fs.GetPath())) {
+              scan_module(dependency, indent + 1);
+            } else if (ModuleSP dependency =
+                           all_modules.lookup(fs.GetFilename())) {
+              scan_module(dependency, indent + 1);
+            } else {
+              if (GetLog(LLDBLog::Types)) {
+                std::string spacer(indent, '-');
+                LOG_PRINTF(GetLog(LLDBLog::Types),
+                           "+%s Could not find %s in images", spacer.c_str(),
+                           fs.GetPath().c_str());
+              }
+            }
+          }
+        }
+      };
+  scan_module(module_sp, 0);
+  for (size_t mi = 0; mi != num_images; ++mi) {
+    auto image_sp = target.GetImages().GetModuleAtIndex(mi);
+    if (!visited_modules.count(image_sp.get()))
+      swift_ast_sp->RegisterSectionModules(*image_sp, module_names);
   }
 
   LOG_PRINTF(GetLog(LLDBLog::Types), "((Target*)%p) = %p",
@@ -4370,6 +4416,7 @@ void SwiftASTContext::RegisterSectionModules(
 
   // Grab all the AST blobs from the symbol vendor.
   auto ast_file_datas = module.GetASTData(eLanguageTypeSwift);
+    if (ast_file_datas.size())
   LOG_PRINTF(GetLog(LLDBLog::Types),
              "(\"%s\") retrieved %zu AST Data blobs from the symbol vendor "
              "(filter=\"%s\").",

lldb/test/API/lang/swift/deployment_target/TestSwiftDeploymentTarget.py

@@ -65,4 +65,4 @@ def test_swift_deployment_target_from_macho(self):
         self.expect("expression f", substrs=["i = 23"])
         self.filecheck('platform shell cat ""%s"' % log, __file__)
 #       CHECK: SwiftASTContextForExpressions::SetTriple({{.*}}apple-macosx11.0.0
-#       CHECK:  SwiftASTContextForExpressions::RegisterSectionModules("a.out") retrieved 0 AST Data blobs
+#       CHECK-NOT: SwiftASTContextForExpressions::RegisterSectionModules("a.out"){{.*}} AST Data blobs

lldb/test/API/lang/swift/expression/import_search_paths/TestSwiftImportSearchPaths.py

@@ -30,22 +30,19 @@ def do_test(self, flag):
             self, 'break here', lldb.SBFileSpec('main.swift'),
             extra_images=['Direct', self.getBuildArtifact('hidden/libIndirect')])
 
-        log = self.getBuildArtifact("types.log")
-        self.expect('settings show '
-                    + 'target.experimental')
-        self.expect("log enable lldb types -f " + log)
+        types_log = self.getBuildArtifact("types.log")
+        self.expect("log enable lldb types -f " + types_log)
         self.expect("expr -- x.inner.hidden", substrs=['=', '42'])
-
-        import io, re
-        logfile = io.open(log, "r", encoding='utf-8')
-        sanity = 0
-        found = 0
-        for line in logfile:
-            if re.match(r'.*SwiftASTContextForModule\("a\.out"\)::LogConfiguration\(\).*hidden$',
-                        line.strip('\n')):
-                sanity += 1
-            elif re.match(r'.*SwiftASTContextForExpressions::LogConfiguration\(\).*hidden$',
-                          line.strip('\n')):
-                found += 1
-        self.assertEqual(sanity, 1)
-        self.assertEqual(found, 1 if flag == 'true' else 0)
+        if flag == 'true':
+            prefix = 'POSITIVE'
+        else:
+            prefix = 'NEGATIVE'
+        self.filecheck('platform shell cat "%s"' % types_log, __file__,
+                       '--check-prefix=CHECK_MOD_'+prefix)
+        self.filecheck('platform shell cat "%s"' % types_log, __file__,
+                       '--check-prefix=CHECK_EXP_'+prefix)
+# CHECK_MOD_POSITIVE: SwiftASTContextForModule("a.out")::LogConfiguration(){{.*hidden$}}
+# CHECK_MOD_NEGATIVE: SwiftASTContextForModule("a.out")::LogConfiguration(){{.*hidden$}}
+# CHECK_EXP_POSITIVE: SwiftASTContextForExpressions::LogConfiguration(){{.*hidden$}}
+# CHECK_EXP_NEGATIVE-NOT: SwiftASTContextForExpressions::LogConfiguration(){{.*hidden$}}
+# CHECK_EXP_NEGATIVE: SwiftASTContextForExpressions::LogConfiguration(){{.*}}Extra clang arguments