[lldb] Fix ppc64 detection in lldb

[serge-sans-paille]

Summary

Currently, ppc64le and ppc64 (defaulting to big endian) have the same
descriptor, thus the linear scan always return ppc64le. Handle that through
subtype.

[labath]

There were probably easier ways to test this, but it's nice to have the core file nonetheless. LGTM, assuming the core is of a reasonable size.

[MaskRay]

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

315

326

Move before EM_RISCV for an alphabetical order.

[serge-sans-paille]

Fix nits

[DavidSpickett]

I reverted this due to an assert: https://lab.llvm.org/buildbot/#/builders/96/builds/22715/steps/6/logs/stdio (set cmake LLVM_ENABLE_ASSERTIONS to ON)

I think you could just add PowerPC to the if (!reg_interface there but first time looking at the code I'm not sure of the consequences of that.

[serge-sans-paille]

In D124760#3488289, @DavidSpickett wrote:

I reverted this due to an assert: https://lab.llvm.org/buildbot/#/builders/96/builds/22715/steps/6/logs/stdio (set cmake LLVM_ENABLE_ASSERTIONS to ON)

I think you could just add PowerPC to the if (!reg_interface there but first time looking at the code I'm not sure of the consequences of that.

Thanks @DavidSpickett for the revert. I think we need to implement RegisterInfoPOSIX_ppc64 for Linux... I'll investiagte that.

[serge-sans-paille]

Change the rest case to something that doesn't require me to implement ppc64be corefile support.

[serge-sans-paille]

@labath does that version look good? I only changed the test.

[labath]

Sure, that's great.

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

case llvm::ELF::ELFCLASS32:
     return ArchSpec::eRISCVSubType_riscv32;
   case llvm::ELF::ELFCLASS64:
     return ArchSpec::eRISCVSubType_riscv64;
   default:
     return ArchSpec::eRISCVSubType_unknown;
   }
 }
 
+static uint32_t ppc64VariantFromElfFlags(const elf::ELFHeader &header) {
+  uint32_t endian = header.e_ident[EI_DATA];
+  if(endian == ELFDATA2LSB)
+    return ArchSpec::eCore_ppc64le_generic;
+  else
+    return ArchSpec::eCore_ppc64_generic;
+}
+
 static uint32_t subTypeFromElfHeader(const elf::ELFHeader &header) {
   if (header.e_machine == llvm::ELF::EM_MIPS)
     return mipsVariantFromElfFlags(header);
   else if (header.e_machine == llvm::ELF::EM_RISCV)
     return riscvVariantFromElfFlags(header);
+  else if (header.e_machine == llvm::ELF::EM_PPC64)
+    return ppc64VariantFromElfFlags(header);
 
   return LLDB_INVALID_CPUTYPE;
 }
 
 char ObjectFileELF::ID;
 
 // Arbitrary constant used as UUID prefix for core files.
 const uint32_t ObjectFileELF::g_core_uuid_magic(0xE210C);

lldb/source/Utility/ArchSpec.cpp

static const ArchDefinitionEntry g_elf_arch_entries[] = {
     {ArchSpec::eCore_sparc_generic, llvm::ELF::EM_SPARC, LLDB_INVALID_CPUTYPE,
      0xFFFFFFFFu, 0xFFFFFFFFu}, // Sparc
     {ArchSpec::eCore_x86_32_i386, llvm::ELF::EM_386, LLDB_INVALID_CPUTYPE,
      0xFFFFFFFFu, 0xFFFFFFFFu}, // Intel 80386
     {ArchSpec::eCore_x86_32_i486, llvm::ELF::EM_IAMCU, LLDB_INVALID_CPUTYPE,
      0xFFFFFFFFu, 0xFFFFFFFFu}, // Intel MCU // FIXME: is this correct?
     {ArchSpec::eCore_ppc_generic, llvm::ELF::EM_PPC, LLDB_INVALID_CPUTYPE,
      0xFFFFFFFFu, 0xFFFFFFFFu}, // PowerPC
-    {ArchSpec::eCore_ppc64le_generic, llvm::ELF::EM_PPC64, LLDB_INVALID_CPUTYPE,
+    {ArchSpec::eCore_ppc64le_generic, llvm::ELF::EM_PPC64, ArchSpec::eCore_ppc64le_generic,
      0xFFFFFFFFu, 0xFFFFFFFFu}, // PowerPC64le
-    {ArchSpec::eCore_ppc64_generic, llvm::ELF::EM_PPC64, LLDB_INVALID_CPUTYPE,
+    {ArchSpec::eCore_ppc64_generic, llvm::ELF::EM_PPC64, ArchSpec::eCore_ppc64_generic,
      0xFFFFFFFFu, 0xFFFFFFFFu}, // PowerPC64
     {ArchSpec::eCore_arm_generic, llvm::ELF::EM_ARM, LLDB_INVALID_CPUTYPE,
      0xFFFFFFFFu, 0xFFFFFFFFu}, // ARM
     {ArchSpec::eCore_arm_aarch64, llvm::ELF::EM_AARCH64, LLDB_INVALID_CPUTYPE,
      0xFFFFFFFFu, 0xFFFFFFFFu}, // ARM64
     {ArchSpec::eCore_s390x_generic, llvm::ELF::EM_S390, LLDB_INVALID_CPUTYPE,
      0xFFFFFFFFu, 0xFFFFFFFFu}, // SystemZ
     {ArchSpec::eCore_sparc9_generic, llvm::ELF::EM_SPARCV9,

lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py

class LinuxCoreTestCase(TestBase):
 
     mydir = TestBase.compute_mydir(__file__)
 
     _aarch64_pid = 37688
     _aarch64_pac_pid = 387
     _i386_pid = 32306
     _x86_64_pid = 32259
     _s390x_pid = 1045
+    _ppc64_pid = 28146
     _ppc64le_pid = 28147
 
     _aarch64_regions = 4
     _i386_regions = 4
     _x86_64_regions = 5
     _s390x_regions = 2
+    _ppc64_regions = 2
     _ppc64le_regions = 2
 
     @skipIfLLVMTargetMissing("AArch64")
     def test_aarch64(self):
         """Test that lldb can read the process information from an aarch64 linux core file."""
         self.do_test("linux-aarch64", self._aarch64_pid,
                      self._aarch64_regions, "a.out")
 
     @skipIfLLVMTargetMissing("X86")
     def test_i386(self):
         """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, "a.out")
 
     @skipIfLLVMTargetMissing("PowerPC")
     def test_ppc64le(self):
         """Test that lldb can read the process information from an ppc64le linux core file."""
         self.do_test("linux-ppc64le", self._ppc64le_pid, self._ppc64le_regions,
                      "linux-ppc64le.ou")
 
+    @skipIfLLVMTargetMissing("PowerPC")
+    def test_ppc64(self):
+        """Test that lldb can read the process information from an ppc64 linux core file."""
+        self.do_test("linux-ppc64", self._ppc64_pid, self._ppc64_regions,
+                     "linux-ppc64.ou")
+
     @skipIfLLVMTargetMissing("X86")
     def test_x86_64(self):
         """Test that lldb can read the process information from an x86_64 linux core file."""
         self.do_test("linux-x86_64", self._x86_64_pid, self._x86_64_regions,
                      "a.out")
 
     @skipIfLLVMTargetMissing("SystemZ")
     def test_s390x(self):