[lldb][LoongArch64] Add support for LoongArch64 in elf-core for lldb (#112296)

When using the lldb command 'target create --core' on the LoongArch64
architecture, this part of the code is required.

Author: lawn123

lldb/source/Plugins/Process/Utility/RegisterContextPOSIX_loongarch64.cpp

@@ -58,7 +58,7 @@ RegisterContextPOSIX_loongarch64::GetRegisterInfoAtIndex(size_t reg) {
 }
 
 size_t RegisterContextPOSIX_loongarch64::GetRegisterSetCount() {
-  return m_register_info_up->GetRegisterCount();
+  return m_register_info_up->GetRegisterSetCount();
 }
 
 const lldb_private::RegisterSet *

lldb/source/Plugins/Process/elf-core/CMakeLists.txt

@@ -10,6 +10,7 @@ add_lldb_library(lldbPluginProcessElfCore PLUGIN
   RegisterContextPOSIXCore_s390x.cpp
   RegisterContextPOSIXCore_x86_64.cpp
   RegisterContextPOSIXCore_riscv64.cpp
+  RegisterContextPOSIXCore_loongarch64.cpp
   RegisterUtilities.cpp
 
   LINK_LIBS

lldb/source/Plugins/Process/elf-core/RegisterContextPOSIXCore_loongarch64.cpp

@@ -0,0 +1,84 @@
+//===-- RegisterContextPOSIXCore_loongarch64.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 "RegisterContextPOSIXCore_loongarch64.h"
+
+#include "lldb/Utility/DataBufferHeap.h"
+
+using namespace lldb_private;
+
+std::unique_ptr<RegisterContextCorePOSIX_loongarch64>
+RegisterContextCorePOSIX_loongarch64::Create(Thread &thread,
+                                             const ArchSpec &arch,
+                                             const DataExtractor &gpregset,
+                                             llvm::ArrayRef<CoreNote> notes) {
+  return std::unique_ptr<RegisterContextCorePOSIX_loongarch64>(
+      new RegisterContextCorePOSIX_loongarch64(
+          thread,
+          std::make_unique<RegisterInfoPOSIX_loongarch64>(arch, Flags()),
+          gpregset, notes));
+}
+
+RegisterContextCorePOSIX_loongarch64::RegisterContextCorePOSIX_loongarch64(
+    Thread &thread,
+    std::unique_ptr<RegisterInfoPOSIX_loongarch64> register_info,
+    const DataExtractor &gpregset, llvm::ArrayRef<CoreNote> notes)
+    : RegisterContextPOSIX_loongarch64(thread, std::move(register_info)) {
+
+  m_gpr.SetData(std::make_shared<DataBufferHeap>(gpregset.GetDataStart(),
+                                                 gpregset.GetByteSize()));
+  m_gpr.SetByteOrder(gpregset.GetByteOrder());
+
+  ArchSpec arch = m_register_info_up->GetTargetArchitecture();
+  DataExtractor fpregset = getRegset(notes, arch.GetTriple(), FPR_Desc);
+  m_fpr.SetData(std::make_shared<DataBufferHeap>(fpregset.GetDataStart(),
+                                                 fpregset.GetByteSize()));
+  m_fpr.SetByteOrder(fpregset.GetByteOrder());
+}
+
+RegisterContextCorePOSIX_loongarch64::~RegisterContextCorePOSIX_loongarch64() =
+    default;
+
+bool RegisterContextCorePOSIX_loongarch64::ReadGPR() { return true; }
+
+bool RegisterContextCorePOSIX_loongarch64::ReadFPR() { return true; }
+
+bool RegisterContextCorePOSIX_loongarch64::WriteGPR() {
+  assert(false && "Writing registers is not allowed for core dumps");
+  return false;
+}
+
+bool RegisterContextCorePOSIX_loongarch64::WriteFPR() {
+  assert(false && "Writing registers is not allowed for core dumps");
+  return false;
+}
+
+bool RegisterContextCorePOSIX_loongarch64::ReadRegister(
+    const RegisterInfo *reg_info, RegisterValue &value) {
+  const uint8_t *src = nullptr;
+  lldb::offset_t offset = reg_info->byte_offset;
+
+  if (IsGPR(reg_info->kinds[lldb::eRegisterKindLLDB])) {
+    src = m_gpr.GetDataStart();
+  } else if (IsFPR(reg_info->kinds[lldb::eRegisterKindLLDB])) {
+    src = m_fpr.GetDataStart();
+    offset -= GetGPRSize();
+  } else {
+    return false;
+  }
+
+  Status error;
+  value.SetFromMemoryData(*reg_info, src + offset, reg_info->byte_size,
+                          lldb::eByteOrderLittle, error);
+  return error.Success();
+}
+
+bool RegisterContextCorePOSIX_loongarch64::WriteRegister(
+    const RegisterInfo *reg_info, const RegisterValue &value) {
+  return false;
+}

lldb/source/Plugins/Process/elf-core/RegisterContextPOSIXCore_loongarch64.h

@@ -0,0 +1,58 @@
+//===-- RegisterContextPOSIXCore_loongarch64.h -------------------*- C++-*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLDB_SOURCE_PLUGINS_PROCESS_ELF_CORE_REGISTERCONTEXTPOSIXCORE_LOONGARCH64_H
+#define LLDB_SOURCE_PLUGINS_PROCESS_ELF_CORE_REGISTERCONTEXTPOSIXCORE_LOONGARCH64_H
+
+#include "Plugins/Process/Utility/RegisterContextPOSIX_loongarch64.h"
+#include "Plugins/Process/Utility/RegisterInfoPOSIX_loongarch64.h"
+
+#include "Plugins/Process/elf-core/RegisterUtilities.h"
+#include "lldb/Target/Thread.h"
+#include "lldb/Utility/DataExtractor.h"
+#include "lldb/Utility/RegisterValue.h"
+
+#include <memory>
+
+class RegisterContextCorePOSIX_loongarch64
+    : public RegisterContextPOSIX_loongarch64 {
+public:
+  static std::unique_ptr<RegisterContextCorePOSIX_loongarch64>
+  Create(lldb_private::Thread &thread, const lldb_private::ArchSpec &arch,
+         const lldb_private::DataExtractor &gpregset,
+         llvm::ArrayRef<lldb_private::CoreNote> notes);
+
+  ~RegisterContextCorePOSIX_loongarch64() override;
+
+  bool ReadRegister(const lldb_private::RegisterInfo *reg_info,
+                    lldb_private::RegisterValue &value) override;
+
+  bool WriteRegister(const lldb_private::RegisterInfo *reg_info,
+                     const lldb_private::RegisterValue &value) override;
+
+protected:
+  RegisterContextCorePOSIX_loongarch64(
+      lldb_private::Thread &thread,
+      std::unique_ptr<RegisterInfoPOSIX_loongarch64> register_info,
+      const lldb_private::DataExtractor &gpregset,
+      llvm::ArrayRef<lldb_private::CoreNote> notes);
+
+  bool ReadGPR() override;
+
+  bool ReadFPR() override;
+
+  bool WriteGPR() override;
+
+  bool WriteFPR() override;
+
+private:
+  lldb_private::DataExtractor m_gpr;
+  lldb_private::DataExtractor m_fpr;
+};
+
+#endif // LLDB_SOURCE_PLUGINS_PROCESS_ELF_CORE_REGISTERCONTEXTPOSIXCORE_LOONGARCH64_H

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

@@ -33,6 +33,7 @@
 #include "RegisterContextLinuxCore_x86_64.h"
 #include "RegisterContextPOSIXCore_arm.h"
 #include "RegisterContextPOSIXCore_arm64.h"
+#include "RegisterContextPOSIXCore_loongarch64.h"
 #include "RegisterContextPOSIXCore_mips64.h"
 #include "RegisterContextPOSIXCore_powerpc.h"
 #include "RegisterContextPOSIXCore_ppc64le.h"
@@ -171,6 +172,7 @@ ThreadElfCore::CreateRegisterContextForFrame(StackFrame *frame) {
 
     if (!reg_interface && arch.GetMachine() != llvm::Triple::aarch64 &&
         arch.GetMachine() != llvm::Triple::arm &&
+        arch.GetMachine() != llvm::Triple::loongarch64 &&
         arch.GetMachine() != llvm::Triple::riscv64) {
       LLDB_LOGF(log, "elf-core::%s:: Architecture(%d) or OS(%d) not supported",
                 __FUNCTION__, arch.GetMachine(), arch.GetTriple().getOS());
@@ -187,6 +189,10 @@ ThreadElfCore::CreateRegisterContextForFrame(StackFrame *frame) {
           *this, std::make_unique<RegisterInfoPOSIX_arm>(arch), m_gpregset_data,
           m_notes);
       break;
+    case llvm::Triple::loongarch64:
+      m_thread_reg_ctx_sp = RegisterContextCorePOSIX_loongarch64::Create(
+          *this, arch, m_gpregset_data, m_notes);
+      break;
     case llvm::Triple::riscv64:
       m_thread_reg_ctx_sp = RegisterContextCorePOSIX_riscv64::Create(
           *this, arch, m_gpregset_data, m_notes);

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

@@ -23,13 +23,15 @@ class LinuxCoreTestCase(TestBase):
     _ppc64le_pid = 28147
     _riscv64_gpr_fpr_pid = 1089
     _riscv64_gpr_only_pid = 97
+    _loongarch64_pid = 456735
 
     _aarch64_regions = 4
     _i386_regions = 4
     _x86_64_regions = 5
     _s390x_regions = 2
     _ppc64le_regions = 2
     _riscv64_regions = 4
+    _loongarch64_regions = 4
 
     @skipIfLLVMTargetMissing("AArch64")
     def test_aarch64(self):
@@ -82,6 +84,16 @@ def test_riscv64_gpr_only(self):
             "a.out",
         )
 
+    @skipIfLLVMTargetMissing("LoongArch")
+    def test_loongarch64(self):
+        """Test that lldb can read the process information from an loongarch64 linux core file."""
+        self.do_test(
+            "linux-loongarch64",
+            self._loongarch64_pid,
+            self._loongarch64_regions,
+            "a.out",
+        )
+
     @skipIfLLVMTargetMissing("X86")
     def test_same_pid_running(self):
         """Test that we read the information from the core correctly even if we have a running
@@ -833,6 +845,106 @@ def test_riscv64_regs_gpr_only(self):
             substrs=["registers were unavailable"],
         )
 
+    @skipIfLLVMTargetMissing("LoongArch")
+    def test_loongarch64_regs(self):
+        # check registers using 64 bit LoongArch core file containing GP and FP registers
+        target = self.dbg.CreateTarget(None)
+        self.assertTrue(target, VALID_TARGET)
+        process = target.LoadCore("linux-loongarch64.core")
+
+        values = {}
+        values["r0"] = "0x0000000000000000"
+        values["r1"] = "0x000000012000016c"
+        values["r2"] = "0x0000000000000000"
+        values["r3"] = "0x00007ffffb8249e0"
+        values["r4"] = "0x0000000000000000"
+        values["r5"] = "0x000000012000010c"
+        values["r6"] = "0x0000000000000000"
+        values["r7"] = "0x0000000000000000"
+        values["r8"] = "0x0000000000000000"
+        values["r9"] = "0x0000000000000000"
+        values["r10"] = "0x0000000000000000"
+        values["r11"] = "0x00000000000000dd"
+        values["r12"] = "0x0000000000000000"
+        values["r13"] = "0x000000000000002f"
+        values["r14"] = "0x0000000000000000"
+        values["r15"] = "0x0000000000000000"
+        values["r16"] = "0x0000000000000000"
+        values["r17"] = "0x0000000000000000"
+        values["r18"] = "0x0000000000000000"
+        values["r19"] = "0x0000000000000000"
+        values["r20"] = "0x0000000000000000"
+        values["r21"] = "0x0000000000000000"
+        values["r22"] = "0x00007ffffb824a10"
+        values["r23"] = "0x0000000000000000"
+        values["r24"] = "0x0000000000000000"
+        values["r25"] = "0x0000000000000000"
+        values["r26"] = "0x0000000000000000"
+        values["r27"] = "0x0000000000000000"
+        values["r28"] = "0x0000000000000000"
+        values["r29"] = "0x0000000000000000"
+        values["r30"] = "0x0000000000000000"
+        values["r31"] = "0x0000000000000000"
+        values["orig_a0"] = "0x0000555556b62d50"
+        values["pc"] = "0x000000012000012c"
+
+        fpr_values = {}
+        fpr_values["f0"] = "0x00000000ffffff05"
+        fpr_values["f1"] = "0x2525252525252525"
+        fpr_values["f2"] = "0x2525252525560005"
+        fpr_values["f3"] = "0x000000000000ffff"
+        fpr_values["f4"] = "0x0000000000000000"
+        fpr_values["f5"] = "0x0000000000000008"
+        fpr_values["f6"] = "0x0f0e0d0c0b0a0908"
+        fpr_values["f7"] = "0xffffffffffffffff"
+        fpr_values["f8"] = "0x6261747563657845"
+        fpr_values["f9"] = "0x766173206562206c"
+        fpr_values["f10"] = "0xffffffffffffffff"
+        fpr_values["f11"] = "0xffffffffffffffff"
+        fpr_values["f12"] = "0xffffffffffffffff"
+        fpr_values["f13"] = "0xffffffffffffffff"
+        fpr_values["f14"] = "0xffffffffffffffff"
+        fpr_values["f15"] = "0xffffffffffffffff"
+        fpr_values["f16"] = "0xffffffffffffffff"
+        fpr_values["f17"] = "0xffffffffffffffff"
+        fpr_values["f18"] = "0xffffffffffffffff"
+        fpr_values["f19"] = "0xffffffffffffffff"
+        fpr_values["f20"] = "0xffffffffffffffff"
+        fpr_values["f21"] = "0xffffffffffffffff"
+        fpr_values["f22"] = "0xffffffffffffffff"
+        fpr_values["f23"] = "0xffffffffffffffff"
+        fpr_values["f24"] = "0xffffffffffffffff"
+        fpr_values["f25"] = "0xffffffffffffffff"
+        fpr_values["f26"] = "0xffffffffffffffff"
+        fpr_values["f27"] = "0xffffffffffffffff"
+        fpr_values["f28"] = "0xffffffffffffffff"
+        fpr_values["f29"] = "0xffffffffffffffff"
+        fpr_values["f30"] = "0xffffffffffffffff"
+        fpr_values["f31"] = "0xffffffffffffffff"
+        fpr_values["fcc0"] = "0x01"
+        fpr_values["fcc1"] = "0x00"
+        fpr_values["fcc2"] = "0x01"
+        fpr_values["fcc3"] = "0x01"
+        fpr_values["fcc4"] = "0x01"
+        fpr_values["fcc5"] = "0x01"
+        fpr_values["fcc6"] = "0x00"
+        fpr_values["fcc7"] = "0x01"
+        fpr_values["fcsr"] = "0x00000000"
+
+        for regname, value in values.items():
+            self.expect(
+                "register read {}".format(regname),
+                substrs=["{} = {}".format(regname, value)],
+            )
+
+        for regname, value in fpr_values.items():
+            self.expect(
+                "register read {}".format(regname),
+                substrs=["{} = {}".format(regname, value)],
+            )
+
+        self.expect("register read --all")
+
     def test_get_core_file_api(self):
         """
         Test SBProcess::GetCoreFile() API can successfully get the core file.