[lldb/Target] Fix frame recognizer list crash when registered with nullptr

lldb/packages/Python/lldbsuite/test/commands/frame/recognizer/TestFrameRecognizer.py

@@ -22,6 +22,9 @@ def test_frame_recognizer_1(self):
         target = self.dbg.CreateTarget(self.getBuildArtifact("a.out"))
         self.assertTrue(target, VALID_TARGET)
 
+        # Clear internal & plugins recognizers that get initialized at launch
+        self.runCmd("frame recognizer clear")
+
         self.runCmd("command script import " + os.path.join(self.getSourceDir(), "recognizer.py"))
 
         self.expect("frame recognizer list",

lldb/source/Target/StackFrameRecognizer.cpp

@@ -70,8 +70,17 @@ class StackFrameRecognizerManagerImpl {
                          std::string symbol, bool regexp)> const &callback) {
     for (auto entry : m_recognizers) {
       if (entry.is_regexp) {
-        callback(entry.recognizer_id, entry.recognizer->GetName(), entry.module_regexp->GetText(),
-                 entry.symbol_regexp->GetText(), true);
+        std::string module_name;
+        std::string symbol_name;
+
+        if (entry.module_regexp)
+          module_name = entry.module_regexp->GetText().str();
+        if (entry.symbol_regexp)
+          symbol_name = entry.symbol_regexp->GetText().str();
+
+        callback(entry.recognizer_id, entry.recognizer->GetName(), module_name,
+                 symbol_name, true);
+
       } else {
         callback(entry.recognizer_id, entry.recognizer->GetName(), entry.module.GetCString(),
                  entry.symbol.GetCString(), false);

lldb/test/Shell/Recognizer/assert.test

@@ -1,4 +1,4 @@
-# UNSUPPORTED: system-windows
+# UNSUPPORTED: system-windows, system-linux
 # RUN: %clang_host -g -O0 %S/Inputs/assert.c -o %t.out
 # RUN: %lldb -b -s %s %t.out | FileCheck %s
 run

lldb/unittests/Target/CMakeLists.txt

@@ -3,13 +3,15 @@ add_lldb_unittest(TargetTests
   MemoryRegionInfoTest.cpp
   ModuleCacheTest.cpp
   PathMappingListTest.cpp
+  StackFrameRecognizerTest.cpp
 
   LINK_LIBS
       lldbCore
       lldbHost
       lldbPluginObjectFileELF
       lldbPluginPlatformLinux
       lldbPluginSymbolFileSymtab
+      lldbTarget
       lldbSymbol
       lldbUtility
       lldbUtilityHelpers

lldb/unittests/Target/StackFrameRecognizerTest.cpp

@@ -0,0 +1,83 @@
+//===-- StackFrameRecognizerTest.cpp --------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Target/StackFrameRecognizer.h"
+#include "Plugins/Platform/Linux/PlatformLinux.h"
+#include "lldb/Core/Debugger.h"
+#include "lldb/Host/FileSystem.h"
+#include "lldb/Host/HostInfo.h"
+#include "lldb/Utility/Reproducer.h"
+#include "lldb/lldb-enumerations.h"
+#include "lldb/lldb-forward.h"
+#include "lldb/lldb-private-enumerations.h"
+#include "lldb/lldb-private.h"
+#include "llvm/Support/FormatVariadic.h"
+#include "gtest/gtest.h"
+
+using namespace lldb_private;
+using namespace lldb_private::repro;
+using namespace lldb;
+
+namespace {
+class StackFrameRecognizerTest : public ::testing::Test {
+public:
+  void SetUp() override {
+    llvm::cantFail(Reproducer::Initialize(ReproducerMode::Off, llvm::None));
+    FileSystem::Initialize();
+    HostInfo::Initialize();
+
+    // Pretend Linux is the host platform.
+    platform_linux::PlatformLinux::Initialize();
+    ArchSpec arch("powerpc64-pc-linux");
+    Platform::SetHostPlatform(
+        platform_linux::PlatformLinux::CreateInstance(true, &arch));
+  }
+
+  void TearDown() override {
+    platform_linux::PlatformLinux::Terminate();
+    HostInfo::Terminate();
+    FileSystem::Terminate();
+    Reproducer::Terminate();
+  }
+};
+
+class DummyStackFrameRecognizer : public StackFrameRecognizer {
+public:
+  std::string GetName() override { return "Dummy StackFrame Recognizer"; }
+};
+
+void RegisterDummyStackFrameRecognizer() {
+  static llvm::once_flag g_once_flag;
+
+  llvm::call_once(g_once_flag, []() {
+    RegularExpressionSP module_regex_sp = nullptr;
+    RegularExpressionSP symbol_regex_sp(new RegularExpression("boom"));
+
+    StackFrameRecognizerSP dummy_recognizer_sp(new DummyStackFrameRecognizer());
+
+    StackFrameRecognizerManager::AddRecognizer(
+        dummy_recognizer_sp, module_regex_sp, symbol_regex_sp, false);
+  });
+}
+
+} // namespace
+
+TEST_F(StackFrameRecognizerTest, NullModuleRegex) {
+  DebuggerSP debugger_sp = Debugger::CreateInstance();
+  ASSERT_TRUE(debugger_sp);
+
+  RegisterDummyStackFrameRecognizer();
+
+  bool any_printed = false;
+  StackFrameRecognizerManager::ForEach(
+      [&any_printed](uint32_t recognizer_id, std::string name,
+                     std::string function, std::string symbol,
+                     bool regexp) { any_printed = true; });
+
+  EXPECT_TRUE(any_printed);
+}