Fix loading core(5) files from NetBSD 7.99.67

[krytarowski]

Summary

This change has been authored by Zachary Turner.

It fixes loading into the debugger core(5) files generated
by NetBSD x86_64 v. 7.99.67.

It does not make exporting the core properties from notes
work, it's limited to elimination of crashes of the debugger.
To trigger the crash LLDB needs to be just executed this
way:

lldb -c ./core

[krytarowski]

Example core(5) file:
http://netbsd.org/~kamil/lldb/top.core

Generated with gcore(1), which snapshoted a running top(1) program.

[krytarowski]

Hmm still wrong.

Later in this code:

// NetBSD per-thread information is stored in notes named
// "NetBSD-CORE@nnn" so match on the initial part of the string.
m_os = llvm::Triple::NetBSD;
if (note.n_type == NETBSD::NT_PROCINFO) {
  ParseNetBSDProcInfo(*thread_data, note_data);
} else if (note.n_type == NETBSD::NT_AUXV) {
  m_auxv = DataExtractor(note_data);
} else if (arch.GetMachine() == llvm::Triple::x86_64 &&
           note.n_type == NETBSD::NT_AMD64_REGS) {
  thread_data->gpregset = note_data;
} else if (arch.GetMachine() == llvm::Triple::x86_64 &&
           note.n_type == NETBSD::NT_AMD64_FPREGS) {
  thread_data->fpregset = note_data;
}

arch.GetMachine() evaluates to llvm::Triple::UnknownArch and gpregset and fpregset is never set.

[krytarowski]

For the reference, I uploaded FreeBSD/amd64 and OpenBSD/i386 core(5) files:

http://netbsd.org/~kamil/lldb/freebsd.10.3.release.p11-top.core.93102
http://netbsd.org/~kamil/lldb/openbsd.6.0-top.core

[krytarowski]

Other BSDs work.

[labath]

This makes all sorts of tests fail. Regardless of your platform you should at least be able to reproduce the following failures:

FAIL: test_FPR_SSE (functionalities/postmortem/elf-core/TestLinuxCore.py)
FAIL: test_image_list_shows_multiple_architectures (functionalities/object-file/TestImageListMultiArchitecture.py)
FAIL: test_local_variables_in_minidump (functionalities/postmortem/minidump-new/TestMiniDumpNew.py)
ERROR: test_deeper_stack_in_minidump (functionalities/postmortem/minidump-new/TestMiniDumpNew.py)
ERROR: test_deeper_stack_in_minidump_with_same_pid_running (functionalities/postmortem/minidump-new/TestMiniDumpNew.py)
ERROR: test_two_cores_same_pid (functionalities/postmortem/minidump-new/TestMiniDumpNew.py)

Let me know if you have problems reproducing these, and I can then take a look.

[krytarowski]

I might need some guidance to address the asserts appropriately in finite time.

In general we set osabi to generic unix (value 0), and NetBSD core(5) files are distinguished only (or mostly) with "NetBSD-CORE*" notes.

[krytarowski]

I will fix the original problem differently. Thanks for help!

source/Core/ArchSpec.cpp

if (!env_specified && compatible_triple.hasEnvironment())
       normalized_triple.setEnvironment(compatible_triple.getEnvironment());
   }
 
   SetTriple(normalized_triple);
   return IsValid();
 }
 
 void ArchSpec::MergeFrom(const ArchSpec &other) {
-  if (TripleVendorIsUnspecifiedUnknown() &&
-      !other.TripleVendorIsUnspecifiedUnknown())
-    GetTriple().setVendor(other.GetTriple().getVendor());
-  if (TripleOSIsUnspecifiedUnknown() && !other.TripleOSIsUnspecifiedUnknown())
-    GetTriple().setOS(other.GetTriple().getOS());
-  if (GetTriple().getArch() == llvm::Triple::UnknownArch)
-    GetTriple().setArch(other.GetTriple().getArch());
-  if (GetTriple().getEnvironment() == llvm::Triple::UnknownEnvironment &&
-      !TripleVendorWasSpecified()) {
-    if (other.TripleVendorWasSpecified())
-      GetTriple().setEnvironment(other.GetTriple().getEnvironment());
-  }
   // If this and other are both arm ArchSpecs and this ArchSpec is a generic
-  // "some kind of arm"
-  // spec but the other ArchSpec is a specific arm core, adopt the specific arm
-  // core.
+  // "some kind of arm" spec but the other ArchSpec is a specific arm core, adopt
+  // the specific arm core.
+  bool ShouldOverrideCore = false;
+
+  if (GetCore() == ArchSpec::kCore_invalid && other.GetCore() != ArchSpec::kCore_invalid)
+    ShouldOverrideCore = true;
   if (GetTriple().getArch() == llvm::Triple::arm &&
-      other.GetTriple().getArch() == llvm::Triple::arm &&
-      IsCompatibleMatch(other) && GetCore() == ArchSpec::eCore_arm_generic &&
-      other.GetCore() != ArchSpec::eCore_arm_generic) {
+    other.GetCore() != ArchSpec::eCore_arm_generic)
+    ShouldOverrideCore = true;
+  if (ShouldOverrideCore) {
     m_core = other.GetCore();
     CoreUpdated(true);
   }
+
+  if (GetTriple().getVendor() == llvm::Triple::UnknownVendor)
+    GetTriple().setVendor(other.GetTriple().getVendor());
+
+  if (GetTriple().getOS() == llvm::Triple::UnknownOS)
+    GetTriple().setOS(other.GetTriple().getOS());
+
+  if (GetTriple().getArch() == llvm::Triple::UnknownArch)
+    GetTriple().setArch(other.GetTriple().getArch());
+
+  if (GetTriple().getEnvironment() == llvm::Triple::UnknownEnvironment)
+    GetTriple().setEnvironment(other.GetTriple().getEnvironment());
 }
 
 bool ArchSpec::SetArchitecture(ArchitectureType arch_type, uint32_t cpu,
                                uint32_t sub, uint32_t os) {
   m_core = kCore_invalid;
   bool update_triple = true;
   const ArchDefinition *arch_def = FindArchDefinition(arch_type);
   if (arch_def) {

source/Plugins/Process/elf-core/ProcessElfCore.cpp

Error ProcessElfCore::DoLoadCore() {
   // it to match the core file which is always single arch.
   ArchSpec arch(m_core_module_sp->GetArchitecture());
 
   ArchSpec target_arch = GetTarget().GetArchitecture();
   ArchSpec core_arch(m_core_module_sp->GetArchitecture());
   target_arch.MergeFrom(core_arch);
   GetTarget().SetArchitecture(target_arch);
  
-  SetUnixSignals(UnixSignals::Create(GetArchitecture()));
+  SetUnixSignals(UnixSignals::Create(target_arch));
 
   // Ensure we found at least one thread that was stopped on a signal.
   bool siginfo_signal_found = false;
   bool prstatus_signal_found = false;
   // Check we found a signal in a SIGINFO note.
   for (const auto &thread_data : m_thread_data) {
     if (thread_data.signo != 0)
       siginfo_signal_found = true;

 
 uint32_t ProcessElfCore::GetNumThreadContexts() {
   if (!m_thread_data_valid)
     DoLoadCore();
   return m_thread_data.size();
 }
 
 ArchSpec ProcessElfCore::GetArchitecture() {
-  ObjectFileELF *core_file =
-      (ObjectFileELF *)(m_core_module_sp->GetObjectFile());
-  ArchSpec arch;
-  core_file->GetArchitecture(arch);
-
-  ArchSpec target_arch = GetTarget().GetArchitecture();
-  
-  if (target_arch.IsMIPS())
-    return target_arch;
-
-  return arch;
+  return GetTarget().GetArchitecture();
 }
 
 const lldb::DataBufferSP ProcessElfCore::GetAuxvData() {
   const uint8_t *start = m_auxv.GetDataStart();
   size_t len = m_auxv.GetByteSize();
   lldb::DataBufferSP buffer(new lldb_private::DataBufferHeap(start, len));
   return buffer;
 }