[LLDB][Minidump] Support minidumps where there are multiple exception streams

lldb/source/Plugins/Process/minidump/MinidumpParser.cpp

@@ -417,14 +417,9 @@ std::vector<const minidump::Module *> MinidumpParser::GetFilteredModuleList() {
   return filtered_modules;
 }
 
-const minidump::ExceptionStream *MinidumpParser::GetExceptionStream() {
-  auto ExpectedStream = GetMinidumpFile().getExceptionStream();
-  if (ExpectedStream)
-    return &*ExpectedStream;
-
-  LLDB_LOG_ERROR(GetLog(LLDBLog::Process), ExpectedStream.takeError(),
-                 "Failed to read minidump exception stream: {0}");
-  return nullptr;
+llvm::iterator_range<ExceptionStreamsIterator>
+MinidumpParser::GetExceptionStreams() {
+  return GetMinidumpFile().getExceptionStreams();
 }
 
 std::optional<minidump::Range>

lldb/source/Plugins/Process/minidump/MinidumpParser.h

@@ -48,6 +48,8 @@ struct Range {
 };
 
 using FallibleMemory64Iterator = llvm::object::MinidumpFile::FallibleMemory64Iterator;
+using ExceptionStreamsIterator =
+    llvm::object::MinidumpFile::ExceptionStreamsIterator;
 
 class MinidumpParser {
 public:
@@ -84,7 +86,7 @@ class MinidumpParser {
   // have the same name, it keeps the copy with the lowest load address.
   std::vector<const minidump::Module *> GetFilteredModuleList();
 
-  const llvm::minidump::ExceptionStream *GetExceptionStream();
+  llvm::iterator_range<ExceptionStreamsIterator> GetExceptionStreams();
 
   std::optional<Range> FindMemoryRange(lldb::addr_t addr);
 

lldb/source/Plugins/Process/minidump/ProcessMinidump.cpp

@@ -157,8 +157,7 @@ ProcessMinidump::ProcessMinidump(lldb::TargetSP target_sp,
                                  const FileSpec &core_file,
                                  DataBufferSP core_data)
     : PostMortemProcess(target_sp, listener_sp, core_file),
-      m_core_data(std::move(core_data)), m_active_exception(nullptr),
-      m_is_wow64(false) {}
+      m_core_data(std::move(core_data)), m_is_wow64(false) {}
 
 ProcessMinidump::~ProcessMinidump() {
   Clear();
@@ -209,7 +208,20 @@ Status ProcessMinidump::DoLoadCore() {
   GetTarget().SetArchitecture(arch, true /*set_platform*/);
 
   m_thread_list = m_minidump_parser->GetThreads();
-  m_active_exception = m_minidump_parser->GetExceptionStream();
+  auto exception_stream_it = m_minidump_parser->GetExceptionStreams();
+  for (auto exception_stream : exception_stream_it) {
+    // If we can't read an exception stream skip it
+    // We should probably serve a warning
+    if (!exception_stream)
+      continue;
+
+    if (!m_exceptions_by_tid
+             .try_emplace(exception_stream->ThreadId, exception_stream.get())
+             .second) {
+      return Status::FromErrorStringWithFormatv(
+          "Duplicate exception stream for tid {0}", exception_stream->ThreadId);
+    }
+  }
 
   SetUnixSignals(UnixSignals::Create(GetArchitecture()));
 
@@ -232,60 +244,57 @@ Status ProcessMinidump::DoDestroy() { return Status(); }
 
 void ProcessMinidump::RefreshStateAfterStop() {
 
-  if (!m_active_exception)
-    return;
-
-  constexpr uint32_t BreakpadDumpRequested = 0xFFFFFFFF;
-  if (m_active_exception->ExceptionRecord.ExceptionCode ==
-      BreakpadDumpRequested) {
-    // This "ExceptionCode" value is a sentinel that is sometimes used
-    // when generating a dump for a process that hasn't crashed.
-
-    // TODO: The definition and use of this "dump requested" constant
-    // in Breakpad are actually Linux-specific, and for similar use
-    // cases on Mac/Windows it defines different constants, referring
-    // to them as "simulated" exceptions; consider moving this check
-    // down to the OS-specific paths and checking each OS for its own
-    // constant.
-    return;
-  }
+  for (const auto &[_, exception_stream] : m_exceptions_by_tid) {
+    constexpr uint32_t BreakpadDumpRequested = 0xFFFFFFFF;
+    if (exception_stream.ExceptionRecord.ExceptionCode ==
+        BreakpadDumpRequested) {
+      // This "ExceptionCode" value is a sentinel that is sometimes used
+      // when generating a dump for a process that hasn't crashed.
+
+      // TODO: The definition and use of this "dump requested" constant
+      // in Breakpad are actually Linux-specific, and for similar use
+      // cases on Mac/Windows it defines different constants, referring
+      // to them as "simulated" exceptions; consider moving this check
+      // down to the OS-specific paths and checking each OS for its own
+      // constant.
+      return;
+    }
 
-  lldb::StopInfoSP stop_info;
-  lldb::ThreadSP stop_thread;
+    lldb::StopInfoSP stop_info;
+    lldb::ThreadSP stop_thread;
 
-  Process::m_thread_list.SetSelectedThreadByID(m_active_exception->ThreadId);
-  stop_thread = Process::m_thread_list.GetSelectedThread();
-  ArchSpec arch = GetArchitecture();
+    Process::m_thread_list.SetSelectedThreadByID(exception_stream.ThreadId);
+    stop_thread = Process::m_thread_list.GetSelectedThread();
+    ArchSpec arch = GetArchitecture();
 
-  if (arch.GetTriple().getOS() == llvm::Triple::Linux) {
-    uint32_t signo = m_active_exception->ExceptionRecord.ExceptionCode;
+    if (arch.GetTriple().getOS() == llvm::Triple::Linux) {
+      uint32_t signo = exception_stream.ExceptionRecord.ExceptionCode;
+      if (signo == 0) {
+        // No stop.
+        return;
+      }
 
-    if (signo == 0) {
-      // No stop.
-      return;
+      stop_info = StopInfo::CreateStopReasonWithSignal(*stop_thread, signo);
+    } else if (arch.GetTriple().getVendor() == llvm::Triple::Apple) {
+      stop_info = StopInfoMachException::CreateStopReasonWithMachException(
+          *stop_thread, exception_stream.ExceptionRecord.ExceptionCode, 2,
+          exception_stream.ExceptionRecord.ExceptionFlags,
+          exception_stream.ExceptionRecord.ExceptionAddress, 0);
+    } else {
+      std::string desc;
+      llvm::raw_string_ostream desc_stream(desc);
+      desc_stream << "Exception "
+                  << llvm::format_hex(
+                         exception_stream.ExceptionRecord.ExceptionCode, 8)
+                  << " encountered at address "
+                  << llvm::format_hex(
+                         exception_stream.ExceptionRecord.ExceptionAddress, 8);
+      stop_info = StopInfo::CreateStopReasonWithException(
+          *stop_thread, desc_stream.str().c_str());
     }
 
-    stop_info = StopInfo::CreateStopReasonWithSignal(
-        *stop_thread, signo);
-  } else if (arch.GetTriple().getVendor() == llvm::Triple::Apple) {
-    stop_info = StopInfoMachException::CreateStopReasonWithMachException(
-        *stop_thread, m_active_exception->ExceptionRecord.ExceptionCode, 2,
-        m_active_exception->ExceptionRecord.ExceptionFlags,
-        m_active_exception->ExceptionRecord.ExceptionAddress, 0);
-  } else {
-    std::string desc;
-    llvm::raw_string_ostream desc_stream(desc);
-    desc_stream << "Exception "
-                << llvm::format_hex(
-                       m_active_exception->ExceptionRecord.ExceptionCode, 8)
-                << " encountered at address "
-                << llvm::format_hex(
-                       m_active_exception->ExceptionRecord.ExceptionAddress, 8);
-    stop_info = StopInfo::CreateStopReasonWithException(
-        *stop_thread, desc_stream.str().c_str());
-  }
-
-  stop_thread->SetStopInfo(stop_info);
+    stop_thread->SetStopInfo(stop_info);
+  }
 }
 
 bool ProcessMinidump::IsAlive() { return true; }
@@ -387,10 +396,9 @@ bool ProcessMinidump::DoUpdateThreadList(ThreadList &old_thread_list,
     LocationDescriptor context_location = thread.Context;
 
     // If the minidump contains an exception context, use it
-    if (m_active_exception != nullptr &&
-        m_active_exception->ThreadId == thread.ThreadId) {
-      context_location = m_active_exception->ThreadContext;
-    }
+    if (auto it = m_exceptions_by_tid.find(thread.ThreadId);
+        it != m_exceptions_by_tid.end())
+      context_location = it->second.ThreadContext;
 
     llvm::ArrayRef<uint8_t> context;
     if (!m_is_wow64)

lldb/source/Plugins/Process/minidump/ProcessMinidump.h

@@ -107,7 +107,8 @@ class ProcessMinidump : public PostMortemProcess {
 private:
   lldb::DataBufferSP m_core_data;
   llvm::ArrayRef<minidump::Thread> m_thread_list;
-  const minidump::ExceptionStream *m_active_exception;
+  std::unordered_map<uint32_t, const minidump::ExceptionStream>
+      m_exceptions_by_tid;
   lldb::CommandObjectSP m_command_sp;
   bool m_is_wow64;
   std::optional<MemoryRegionInfos> m_memory_regions;

lldb/test/API/functionalities/postmortem/minidump-new/TestMiniDumpNew.py

@@ -505,8 +505,22 @@ def test_minidump_memory64list(self):
         self.assertEqual(region.GetRegionBase(), 0x7FFF12A84030)
         self.assertTrue(region.GetRegionEnd(), 0x7FFF12A84030 + 0x2FD0)
         self.assertTrue(region_info_list.GetMemoryRegionAtIndex(1, region))
-        self.assertEqual(region.GetRegionBase(), 0x00007fff12a87000)
-        self.assertTrue(region.GetRegionEnd(), 0x00007fff12a87000 + 0x00000018)
+        self.assertEqual(region.GetRegionBase(), 0x00007FFF12A87000)
+        self.assertTrue(region.GetRegionEnd(), 0x00007FFF12A87000 + 0x00000018)
         self.assertTrue(region_info_list.GetMemoryRegionAtIndex(2, region))
-        self.assertEqual(region.GetRegionBase(), 0x00007fff12a87018)
-        self.assertTrue(region.GetRegionEnd(), 0x00007fff12a87018 + 0x00000400)
+        self.assertEqual(region.GetRegionBase(), 0x00007FFF12A87018)
+        self.assertTrue(region.GetRegionEnd(), 0x00007FFF12A87018 + 0x00000400)
+
+    def test_multiple_exceptions_or_signals(self):
+        """Test that lldb can read the exception information from the Minidump."""
+        print("Starting to read multiple-sigsev.yaml")
+        self.process_from_yaml("multiple-sigsev.yaml")
+        print("Done reading multiple-sigsev.yaml")
+        self.check_state()
+        # This process crashed due to a segmentation fault in both it's threads.
+        self.assertEqual(self.process.GetNumThreads(), 2)
+        for i in range(2):
+            thread = self.process.GetThreadAtIndex(i)
+            self.assertStopReason(thread.GetStopReason(), lldb.eStopReasonSignal)
+            stop_description = thread.GetStopDescription(256)
+            self.assertIn("SIGSEGV", stop_description)

lldb/test/API/functionalities/postmortem/minidump-new/multiple-sigsev.yaml

@@ -0,0 +1,39 @@
+--- !minidump
+Streams:
+  - Type:            ThreadList
+    Threads:
+      - Thread Id:       0x1B4F23
+        Context:         0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000B0010000000000033000000000000000000000006020100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000010A234EBFC7F000010A234EBFC7F00000000000000000000F09C34EBFC7F0000C0A91ABCE97F00000000000000000000A0163FBCE97F00004602000000000000921C40000000000030A434EBFC7F000000000000000000000000000000000000C61D4000000000007F0300000000000000000000000000000000000000000000801F0000FFFF0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000FFFF00FFFFFFFFFFFFFF00FFFFFFFF25252525252525252525252525252525000000000000000000000000000000000000000000000000000000000000000000FFFF00FFFFFFFFFFFFFF00FFFFFFFF0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000FF00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
+        Stack:
+          Start of Memory Range: 0x7FFFFFFFD348
+          Content:         ''
+      - Thread Id:       0x1B6D22
+        Context:         0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000B0010000000000033000000000000000000000006020100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000010A234EBFC7F000010A234EBFC7F00000000000000000000F09C34EBFC7F0000C0A91ABCE97F00000000000000000000A0163FBCE97F00004602000000000000921C40000000000030A434EBFC7F000000000000000000000000000000000000C61D4000000000007F0300000000000000000000000000000000000000000000801F0000FFFF0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000FFFF00FFFFFFFFFFFFFF00FFFFFFFF25252525252525252525252525252525000000000000000000000000000000000000000000000000000000000000000000FFFF00FFFFFFFFFFFFFF00FFFFFFFF0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000FF00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
+        Stack:
+          Start of Memory Range: 0x7FFFF75FDE28
+          Content:         ''
+  - Type:            ModuleList
+    Modules:
+      - Base of Image:   0x0000000000400000
+        Size of Image:   0x00017000
+        Module Name:     'a.out'
+        CodeView Record: ''
+  - Type:            SystemInfo
+    Processor Arch:  AMD64
+    Platform ID:     Linux
+    CSD Version:     'Linux 3.13'
+    CPU:
+      Vendor ID:       GenuineIntel
+      Version Info:    0x00000000
+      Feature Info:    0x00000000
+  - Type:            Exception
+    Thread ID:       0x1B4F23
+    Exception Record:
+      Exception Code:  0xB
+    Thread Context:  00000000
+  - Type:            Exception
+    Thread ID:       0x1B6D22
+    Exception Record:
+      Exception Code:  0xB
+    Thread Context:  00000000
+...

lldb/unittests/Process/minidump/MinidumpParserTest.cpp

@@ -251,10 +251,15 @@ TEST_F(MinidumpParserTest, GetFilteredModuleList) {
 
 TEST_F(MinidumpParserTest, GetExceptionStream) {
   SetUpData("linux-x86_64.dmp");
-  const llvm::minidump::ExceptionStream *exception_stream =
-      parser->GetExceptionStream();
-  ASSERT_NE(nullptr, exception_stream);
-  ASSERT_EQ(11UL, exception_stream->ExceptionRecord.ExceptionCode);
+  auto exception_streams = parser->GetExceptionStreams();
+  size_t count = 0;
+  for (auto exception_stream : exception_streams) {
+    ASSERT_THAT_EXPECTED(exception_stream, llvm::Succeeded());
+    ASSERT_EQ(16001UL, exception_stream->ThreadId);
+    count++;
+  }
+
+  ASSERT_THAT(1UL, count);
 }
 
 void check_mem_range_exists(MinidumpParser &parser, const uint64_t range_start,