[LLDB][MIPS] Fix Core file Architecture and OS information.

Reviewers: labath, clayborg

Subscribers: jaydeep, bhushan, lldb-commits, slthakur

Differential Revision: https://reviews.llvm.org/D31280

llvm-svn: 299199

lldb/packages/Python/lldbsuite/test/functionalities/postmortem/elf-core/TestLinuxCore.py

@@ -21,10 +21,14 @@ class LinuxCoreTestCase(TestBase):
     _i386_pid = 32306
     _x86_64_pid = 32259
     _s390x_pid = 1045
+    _mips64_n64_pid = 25619
+    _mips64_n32_pid = 3670
+    _mips_o32_pid = 3532
 
     _i386_regions = 4
     _x86_64_regions = 5
     _s390x_regions = 2
+    _mips_regions = 5
 
     def setUp(self):
         super(LinuxCoreTestCase, self).setUp()
@@ -40,6 +44,18 @@ class LinuxCoreTestCase(TestBase):
         """Test that lldb can read the process information from an i386 linux core file."""
         self.do_test("linux-i386", self._i386_pid, self._i386_regions)
 
+    def test_mips_o32(self):
+        """Test that lldb can read the process information from an MIPS O32 linux core file."""
+        self.do_test("linux-mipsel-gnuabio32", self._mips_o32_pid, self._mips_regions)
+
+    def test_mips_n32(self):
+        """Test that lldb can read the process information from an MIPS N32 linux core file """
+        self.do_test("linux-mips64el-gnuabin32", self._mips64_n32_pid, self._mips_regions)
+
+    def test_mips_n64(self):
+        """Test that lldb can read the process information from an MIPS N64 linux core file """
+        self.do_test("linux-mips64el-gnuabi64", self._mips64_n64_pid, self._mips_regions)
+
     @skipIf(oslist=['windows'])
     @skipIf(triple='^mips')
     def test_x86_64(self):

lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp

@@ -288,10 +288,26 @@ static uint32_t kalimbaVariantFromElfFlags(const elf::elf_word e_flags) {
   return kal_arch_variant;
 }
 
-static uint32_t mipsVariantFromElfFlags(const elf::elf_word e_flags,
-                                        uint32_t endian) {
-  const uint32_t mips_arch = e_flags & llvm::ELF::EF_MIPS_ARCH;
+static uint32_t mipsVariantFromElfFlags (const elf::ELFHeader &header) {
+  const uint32_t mips_arch = header.e_flags & llvm::ELF::EF_MIPS_ARCH;
+  uint32_t endian = header.e_ident[EI_DATA];
   uint32_t arch_variant = ArchSpec::eMIPSSubType_unknown;
+  uint32_t fileclass = header.e_ident[EI_CLASS];
+
+  // If there aren't any elf flags available (e.g core elf file) then return default 
+  // 32 or 64 bit arch (without any architecture revision) based on object file's class.
+  if (header.e_type == ET_CORE) {
+    switch (fileclass) {
+    case llvm::ELF::ELFCLASS32:
+      return (endian == ELFDATA2LSB) ? ArchSpec::eMIPSSubType_mips32el
+                                     : ArchSpec::eMIPSSubType_mips32;
+    case llvm::ELF::ELFCLASS64:
+      return (endian == ELFDATA2LSB) ? ArchSpec::eMIPSSubType_mips64el
+                                     : ArchSpec::eMIPSSubType_mips64;
+    default:
+      return arch_variant;
+    }
+  }
 
   switch (mips_arch) {
   case llvm::ELF::EF_MIPS_ARCH_1:
@@ -326,7 +342,7 @@ static uint32_t mipsVariantFromElfFlags(const elf::elf_word e_flags,
 
 static uint32_t subTypeFromElfHeader(const elf::ELFHeader &header) {
   if (header.e_machine == llvm::ELF::EM_MIPS)
-    return mipsVariantFromElfFlags(header.e_flags, header.e_ident[EI_DATA]);
+    return mipsVariantFromElfFlags(header);
 
   return llvm::ELF::EM_CSR_KALIMBA == header.e_machine
              ? kalimbaVariantFromElfFlags(header.e_flags)
@@ -1349,6 +1365,10 @@ ObjectFileELF::RefineModuleDetailsFromNote(lldb_private::DataExtractor &data,
         }
         break;
       }
+      if (arch_spec.IsMIPS() &&
+          arch_spec.GetTriple().getOS() == llvm::Triple::OSType::UnknownOS)
+        // The note.n_name == LLDB_NT_OWNER_GNU is valid for Linux platform
+        arch_spec.GetTriple().setOS(llvm::Triple::OSType::Linux);
     }
     // Process NetBSD ELF notes.
     else if ((note.n_name == LLDB_NT_OWNER_NETBSD) &&
@@ -1450,6 +1470,12 @@ ObjectFileELF::RefineModuleDetailsFromNote(lldb_private::DataExtractor &data,
             break;
           }
         }
+        if (arch_spec.IsMIPS() &&
+            arch_spec.GetTriple().getOS() == llvm::Triple::OSType::UnknownOS)
+          // In case of MIPSR6, the LLDB_NT_OWNER_GNU note is missing
+          // for some cases (e.g. compile with -nostdlib)
+          // Hence set OS to Linux
+          arch_spec.GetTriple().setOS(llvm::Triple::OSType::Linux); 
       }
     }
 

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

@@ -214,9 +214,12 @@ Error ProcessElfCore::DoLoadCore() {
   // Even if the architecture is set in the target, we need to override
   // it to match the core file which is always single arch.
   ArchSpec arch(m_core_module_sp->GetArchitecture());
-  if (arch.IsValid())
-    GetTarget().SetArchitecture(arch);
 
+  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()));
 
   // Ensure we found at least one thread that was stopped on a signal.
@@ -370,6 +373,10 @@ size_t ProcessElfCore::DoReadMemory(lldb::addr_t addr, void *buf, size_t size,
   lldb::addr_t bytes_left =
       0; // Number of bytes available in the core file from the given address
 
+  // Don't proceed if core file doesn't contain the actual data for this address range.
+  if (file_start == file_end)
+    return 0;
+
   // Figure out how many on-disk bytes remain in this segment
   // starting at the given offset
   if (file_end > file_start + offset)
@@ -652,6 +659,8 @@ Error ProcessElfCore::ParseThreadContextsFromNoteSegment(
         // The result from FXSAVE is in NT_PRXFPREG for i386 core files
         if (arch.GetCore() == ArchSpec::eCore_x86_64_x86_64)
           thread_data->fpregset = note_data;
+        else if(arch.IsMIPS())
+          thread_data->fpregset = note_data;
         break;
       case NT_PRPSINFO:
         have_prpsinfo = true;
@@ -719,6 +728,12 @@ ArchSpec ProcessElfCore::GetArchitecture() {
       (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;
 }