[llvm-branch-commits] [lldb] [lldb][LoongArch] Function calls support in lldb expressions (PR #114742)

via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Tue Nov 5 02:37:37 PST 2024


================
@@ -0,0 +1,664 @@
+//===-- ABISysV_loongarch.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 "ABISysV_loongarch.h"
+
+#include <array>
+#include <limits>
+#include <sstream>
+
+#include "llvm/IR/DerivedTypes.h"
+
+#include "Utility/LoongArch_DWARF_Registers.h"
+#include "lldb/Core/PluginManager.h"
+#include "lldb/Core/Value.h"
+#include "lldb/Target/RegisterContext.h"
+#include "lldb/Target/StackFrame.h"
+#include "lldb/Target/Thread.h"
+#include "lldb/Utility/LLDBLog.h"
+#include "lldb/Utility/RegisterValue.h"
+#include "lldb/ValueObject/ValueObjectConstResult.h"
+
+#define DEFINE_REG_NAME(reg_num) ConstString(#reg_num).GetCString()
+#define DEFINE_REG_NAME_STR(reg_name) ConstString(reg_name).GetCString()
+
+// The ABI is not a source of such information as size, offset, encoding, etc.
+// of a register. Just provides correct dwarf and eh_frame numbers.
+
+#define DEFINE_GENERIC_REGISTER_STUB(dwarf_num, str_name, generic_num)         \
+  {                                                                            \
+      DEFINE_REG_NAME(dwarf_num),                                              \
+      DEFINE_REG_NAME_STR(str_name),                                           \
+      0,                                                                       \
+      0,                                                                       \
+      eEncodingInvalid,                                                        \
+      eFormatDefault,                                                          \
+      {dwarf_num, dwarf_num, generic_num, LLDB_INVALID_REGNUM, dwarf_num},     \
+      nullptr,                                                                 \
+      nullptr,                                                                 \
+      nullptr,                                                                 \
+  }
+
+#define DEFINE_REGISTER_STUB(dwarf_num, str_name)                              \
+  DEFINE_GENERIC_REGISTER_STUB(dwarf_num, str_name, LLDB_INVALID_REGNUM)
+
+using namespace lldb;
+using namespace lldb_private;
+
+LLDB_PLUGIN_DEFINE_ADV(ABISysV_loongarch, ABILoongArch)
+
+namespace {
+namespace dwarf {
+enum regnums {
+  r0,
+  ra,
+  r1 = ra,
+  r2,
+  sp,
+  r3 = sp,
+  r4,
+  r5,
+  r6,
+  r7,
+  r8,
+  r9,
+  r10,
+  r11,
+  r12,
+  r13,
+  r14,
+  r15,
+  r16,
+  r17,
+  r18,
+  r19,
+  r20,
+  r21,
+  fp,
+  r22 = fp,
+  r23,
+  r24,
+  r25,
+  r26,
+  r27,
+  r28,
+  r29,
+  r30,
+  r31,
+  pc
+};
+
+static const std::array<RegisterInfo, 33> g_register_infos = {
+    {DEFINE_REGISTER_STUB(r0, nullptr),
+     DEFINE_GENERIC_REGISTER_STUB(r1, nullptr, LLDB_REGNUM_GENERIC_RA),
+     DEFINE_REGISTER_STUB(r2, nullptr),
+     DEFINE_GENERIC_REGISTER_STUB(r3, nullptr, LLDB_REGNUM_GENERIC_SP),
+     DEFINE_GENERIC_REGISTER_STUB(r4, nullptr, LLDB_REGNUM_GENERIC_ARG1),
+     DEFINE_GENERIC_REGISTER_STUB(r5, nullptr, LLDB_REGNUM_GENERIC_ARG2),
+     DEFINE_GENERIC_REGISTER_STUB(r6, nullptr, LLDB_REGNUM_GENERIC_ARG3),
+     DEFINE_GENERIC_REGISTER_STUB(r7, nullptr, LLDB_REGNUM_GENERIC_ARG4),
+     DEFINE_GENERIC_REGISTER_STUB(r8, nullptr, LLDB_REGNUM_GENERIC_ARG5),
+     DEFINE_GENERIC_REGISTER_STUB(r9, nullptr, LLDB_REGNUM_GENERIC_ARG6),
+     DEFINE_GENERIC_REGISTER_STUB(r10, nullptr, LLDB_REGNUM_GENERIC_ARG7),
+     DEFINE_GENERIC_REGISTER_STUB(r11, nullptr, LLDB_REGNUM_GENERIC_ARG8),
+     DEFINE_REGISTER_STUB(r12, nullptr),
+     DEFINE_REGISTER_STUB(r13, nullptr),
+     DEFINE_REGISTER_STUB(r14, nullptr),
+     DEFINE_REGISTER_STUB(r15, nullptr),
+     DEFINE_REGISTER_STUB(r16, nullptr),
+     DEFINE_REGISTER_STUB(r17, nullptr),
+     DEFINE_REGISTER_STUB(r18, nullptr),
+     DEFINE_REGISTER_STUB(r19, nullptr),
+     DEFINE_REGISTER_STUB(r20, nullptr),
+     DEFINE_REGISTER_STUB(r21, nullptr),
+     DEFINE_GENERIC_REGISTER_STUB(r22, nullptr, LLDB_REGNUM_GENERIC_FP),
+     DEFINE_REGISTER_STUB(r23, nullptr),
+     DEFINE_REGISTER_STUB(r24, nullptr),
+     DEFINE_REGISTER_STUB(r25, nullptr),
+     DEFINE_REGISTER_STUB(r26, nullptr),
+     DEFINE_REGISTER_STUB(r27, nullptr),
+     DEFINE_REGISTER_STUB(r28, nullptr),
+     DEFINE_REGISTER_STUB(r29, nullptr),
+     DEFINE_REGISTER_STUB(r30, nullptr),
+     DEFINE_REGISTER_STUB(r31, nullptr),
+     DEFINE_GENERIC_REGISTER_STUB(pc, nullptr, LLDB_REGNUM_GENERIC_PC)}};
+} // namespace dwarf
+} // namespace
+
+// Number of argument registers (the base integer calling convention
+// provides 8 argument registers, a0-a7)
+static constexpr size_t g_regs_for_args_count = 8U;
+
+const RegisterInfo *ABISysV_loongarch::GetRegisterInfoArray(uint32_t &count) {
+  count = dwarf::g_register_infos.size();
+  return dwarf::g_register_infos.data();
+}
+
+//------------------------------------------------------------------
+// Static Functions
+//------------------------------------------------------------------
+
+ABISP
+ABISysV_loongarch::CreateInstance(ProcessSP process_sp, const ArchSpec &arch) {
+  llvm::Triple::ArchType machine = arch.GetTriple().getArch();
+
+  if (llvm::Triple::loongarch32 != machine &&
+      llvm::Triple::loongarch64 != machine)
+    return ABISP();
+
+  ABISysV_loongarch *abi =
+      new ABISysV_loongarch(std::move(process_sp), MakeMCRegisterInfo(arch));
+  if (abi)
+    abi->SetIsLA64((llvm::Triple::loongarch64 == machine) ? true : false);
+  return ABISP(abi);
+}
+
+static bool UpdateRegister(RegisterContext *reg_ctx,
+                           const lldb::RegisterKind reg_kind,
+                           const uint32_t reg_num, const addr_t value) {
+  Log *log = GetLog(LLDBLog::Expressions);
+
+  const RegisterInfo *reg_info = reg_ctx->GetRegisterInfo(reg_kind, reg_num);
+
+  LLDB_LOG(log, "Writing {0}: 0x{1:x}", reg_info->name,
+           static_cast<uint64_t>(value));
+  if (!reg_ctx->WriteRegisterFromUnsigned(reg_info, value)) {
+    LLDB_LOG(log, "Writing {0}: failed", reg_info->name);
+    return false;
+  }
+  return true;
+}
+
+static void LogInitInfo(Log &log, const Thread &thread, addr_t sp,
+                        addr_t func_addr, addr_t return_addr,
+                        const llvm::ArrayRef<addr_t> args) {
+  std::stringstream ss;
+  ss << "ABISysV_loongarch::PrepareTrivialCall"
+     << " (tid = 0x" << std::hex << thread.GetID() << ", sp = 0x" << sp
+     << ", func_addr = 0x" << func_addr << ", return_addr = 0x" << return_addr;
+
+  for (auto [idx, arg] : enumerate(args))
+    ss << ", arg" << std::dec << idx << " = 0x" << std::hex << arg;
+  ss << ")";
+  log.PutString(ss.str());
+}
+
+bool ABISysV_loongarch::PrepareTrivialCall(Thread &thread, addr_t sp,
+                                           addr_t func_addr, addr_t return_addr,
+                                           llvm::ArrayRef<addr_t> args) const {
+  Log *log = GetLog(LLDBLog::Expressions);
+  if (log)
+    LogInitInfo(*log, thread, sp, func_addr, return_addr, args);
+
+  const auto reg_ctx_sp = thread.GetRegisterContext();
+  if (!reg_ctx_sp) {
+    LLDB_LOG(log, "Failed to get RegisterContext");
+    return false;
+  }
+
+  if (args.size() > g_regs_for_args_count) {
+    LLDB_LOG(log, "Function has {0} arguments, but only {1} are allowed!",
+             args.size(), g_regs_for_args_count);
+    return false;
+  }
+
+  // Write arguments to registers
+  for (auto [idx, arg] : enumerate(args)) {
+    const RegisterInfo *reg_info = reg_ctx_sp->GetRegisterInfo(
+        eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG1 + idx);
+    LLDB_LOG(log, "About to write arg{0} (0x{1:x}) into {2}", idx, arg,
+             reg_info->name);
+
+    if (!reg_ctx_sp->WriteRegisterFromUnsigned(reg_info, arg)) {
+      LLDB_LOG(log, "Failed to write arg{0} (0x{1:x}) into {2}", idx, arg,
+               reg_info->name);
+      return false;
+    }
+  }
+
+  if (!UpdateRegister(reg_ctx_sp.get(), eRegisterKindGeneric,
+                      LLDB_REGNUM_GENERIC_PC, func_addr))
+    return false;
+  if (!UpdateRegister(reg_ctx_sp.get(), eRegisterKindGeneric,
+                      LLDB_REGNUM_GENERIC_SP, sp))
+    return false;
+  if (!UpdateRegister(reg_ctx_sp.get(), eRegisterKindGeneric,
+                      LLDB_REGNUM_GENERIC_RA, return_addr))
+    return false;
+
+  LLDB_LOG(log, "ABISysV_riscv::{0}() success", __FUNCTION__);
+  return true;
+}
+
+bool ABISysV_loongarch::GetArgumentValues(Thread &thread,
+                                          ValueList &values) const {
+  // TODO: Implement
+  return false;
+}
+
+Status ABISysV_loongarch::SetReturnValueObject(StackFrameSP &frame_sp,
+                                               ValueObjectSP &new_value_sp) {
+  Status result;
+  if (!new_value_sp) {
+    result = Status::FromErrorString("Empty value object for return value.");
+    return result;
+  }
+
+  CompilerType compiler_type = new_value_sp->GetCompilerType();
+  if (!compiler_type) {
+    result = Status::FromErrorString("Null clang type for return value.");
+    return result;
+  }
+
+  auto &reg_ctx = *frame_sp->GetThread()->GetRegisterContext();
+
+  bool is_signed = false;
+  if (!compiler_type.IsIntegerOrEnumerationType(is_signed) &&
+      !compiler_type.IsPointerType()) {
+    result = Status::FromErrorString(
+        "We don't support returning other types at present");
+    return result;
+  }
+
+  DataExtractor data;
+  size_t num_bytes = new_value_sp->GetData(data, result);
+
+  if (result.Fail()) {
+    result = Status::FromErrorStringWithFormat(
+        "Couldn't convert return value to raw data: %s", result.AsCString());
+    return result;
+  }
+
+  size_t reg_size = m_is_la64 ? 8 : 4;
+  if (num_bytes <= 2 * reg_size) {
+    offset_t offset = 0;
+    uint64_t raw_value = data.GetMaxU64(&offset, num_bytes);
+
+    auto reg_info =
+        reg_ctx.GetRegisterInfo(eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG1);
+    if (!reg_ctx.WriteRegisterFromUnsigned(reg_info, raw_value)) {
+      result = Status::FromErrorStringWithFormat(
+          "Couldn't write value to register %s", reg_info->name);
+      return result;
+    }
+
+    if (num_bytes <= reg_size)
+      return result; // Successfully written.
+
+    // for loongarch32, get the upper 32 bits from raw_value and write them
+    // for loongarch64, get the next 64 bits from data and write them
+    if (4 == reg_size)
+      raw_value >>= 32;
+    else
+      raw_value = data.GetMaxU64(&offset, num_bytes - reg_size);
+    reg_info =
+        reg_ctx.GetRegisterInfo(eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG2);
+    if (!reg_ctx.WriteRegisterFromUnsigned(reg_info, raw_value)) {
+      result = Status::FromErrorStringWithFormat(
+          "Couldn't write value to register %s", reg_info->name);
+    }
+
+    return result;
+  }
+
+  result = Status::FromErrorString(
+      "We don't support returning large integer values at present.");
+  return result;
+}
+
+template <typename T>
+static void SetInteger(Scalar &scalar, uint64_t raw_value, bool is_signed) {
+  raw_value &= std::numeric_limits<T>::max();
+  if (is_signed)
+    scalar = static_cast<typename std::make_signed<T>::type>(raw_value);
+  else
+    scalar = static_cast<T>(raw_value);
+}
+
+static bool SetSizedInteger(Scalar &scalar, uint64_t raw_value,
+                            uint8_t size_in_bytes, bool is_signed) {
+  switch (size_in_bytes) {
+  default:
+    return false;
+
+  case sizeof(uint64_t):
+    SetInteger<uint64_t>(scalar, raw_value, is_signed);
+    break;
+
+  case sizeof(uint32_t):
+    SetInteger<uint32_t>(scalar, raw_value, is_signed);
+    break;
+
+  case sizeof(uint16_t):
+    SetInteger<uint16_t>(scalar, raw_value, is_signed);
+    break;
+
+  case sizeof(uint8_t):
+    SetInteger<uint8_t>(scalar, raw_value, is_signed);
+    break;
+  }
+
+  return true;
+}
+
+static bool SetSizedFloat(Scalar &scalar, uint64_t raw_value,
+                          uint8_t size_in_bytes) {
+  switch (size_in_bytes) {
+  default:
+    return false;
+
+  case sizeof(uint64_t):
+    scalar = *reinterpret_cast<double *>(&raw_value);
+    break;
+
+  case sizeof(uint32_t):
+    scalar = *reinterpret_cast<float *>(&raw_value);
+    break;
+  }
+
+  return true;
+}
+
+static ValueObjectSP GetValObjFromIntRegs(Thread &thread,
+                                          const RegisterContextSP &reg_ctx,
+                                          llvm::Triple::ArchType machine,
+                                          uint32_t type_flags,
+                                          uint32_t byte_size) {
+  Value value;
+  ValueObjectSP return_valobj_sp;
+  auto reg_info_a0 =
+      reg_ctx->GetRegisterInfo(eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG1);
+  auto reg_info_a1 =
+      reg_ctx->GetRegisterInfo(eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG2);
+  uint64_t raw_value;
+
+  switch (byte_size) {
+  case sizeof(uint32_t):
+    // Read a0 to get the arg
+    raw_value = reg_ctx->ReadRegisterAsUnsigned(reg_info_a0, 0) & UINT32_MAX;
+    break;
+  case sizeof(uint64_t):
+    raw_value = reg_ctx->ReadRegisterAsUnsigned(reg_info_a0, 0);
+    break;
+  case 16: {
+    // Create the ValueObjectSP here and return
+    std::unique_ptr<DataBufferHeap> heap_data_up(
+        new DataBufferHeap(byte_size, 0));
+    const ByteOrder byte_order = thread.GetProcess()->GetByteOrder();
+    RegisterValue reg_value_a0, reg_value_a1;
+    if (reg_ctx->ReadRegister(reg_info_a0, reg_value_a0) &&
+        reg_ctx->ReadRegister(reg_info_a1, reg_value_a1)) {
+      Status error;
+      if (reg_value_a0.GetAsMemoryData(*reg_info_a0,
+                                       heap_data_up->GetBytes() + 0, 8,
+                                       byte_order, error) &&
+          reg_value_a1.GetAsMemoryData(*reg_info_a1,
+                                       heap_data_up->GetBytes() + 8, 8,
+                                       byte_order, error)) {
+        value.SetBytes(heap_data_up.release(), byte_size);
+        return ValueObjectConstResult::Create(
+            thread.GetStackFrameAtIndex(0).get(), value, ConstString(""));
+      }
+    }
+    break;
+  }
+  default:
+    return return_valobj_sp;
+  }
+
+  if (type_flags & eTypeIsInteger) {
+    const bool is_signed = (type_flags & eTypeIsSigned) != 0;
+    if (!SetSizedInteger(value.GetScalar(), raw_value, byte_size, is_signed))
+      return return_valobj_sp;
+  } else if (type_flags & eTypeIsFloat) {
+    if (!SetSizedFloat(value.GetScalar(), raw_value, byte_size))
+      return return_valobj_sp;
+  } else
+    return return_valobj_sp;
+
+  value.SetValueType(Value::ValueType::Scalar);
+  return_valobj_sp = ValueObjectConstResult::Create(
+      thread.GetStackFrameAtIndex(0).get(), value, ConstString(""));
+  return return_valobj_sp;
+}
+
+static ValueObjectSP GetValObjFromFPRegs(Thread &thread,
+                                         const RegisterContextSP &reg_ctx,
+                                         llvm::Triple::ArchType machine,
+                                         uint32_t type_flags,
+                                         uint32_t byte_size) {
+  auto reg_info_fa0 = reg_ctx->GetRegisterInfoByName("f0");
+  bool use_fp_regs = false;
+  ValueObjectSP return_valobj_sp;
+
+  if (byte_size <= 8)
+    use_fp_regs = true;
+
+  if (use_fp_regs) {
+    uint64_t raw_value;
+    Value value;
+    raw_value = reg_ctx->ReadRegisterAsUnsigned(reg_info_fa0, 0);
+    if (!SetSizedFloat(value.GetScalar(), raw_value, byte_size))
+      return return_valobj_sp;
+    value.SetValueType(Value::ValueType::Scalar);
+    return ValueObjectConstResult::Create(thread.GetStackFrameAtIndex(0).get(),
+                                          value, ConstString(""));
+  }
+  // we should never reach this, but if we do, use the integer registers
+  return GetValObjFromIntRegs(thread, reg_ctx, machine, type_flags, byte_size);
+}
+
+ValueObjectSP ABISysV_loongarch::GetReturnValueObjectSimple(
+    Thread &thread, CompilerType &compiler_type) const {
+  ValueObjectSP return_valobj_sp;
+
+  if (!compiler_type)
+    return return_valobj_sp;
+
+  auto reg_ctx = thread.GetRegisterContext();
+  if (!reg_ctx)
+    return return_valobj_sp;
+
+  Value value;
+  value.SetCompilerType(compiler_type);
+
+  const uint32_t type_flags = compiler_type.GetTypeInfo();
+  const size_t byte_size = compiler_type.GetByteSize(&thread).value_or(0);
+  const ArchSpec arch = thread.GetProcess()->GetTarget().GetArchitecture();
+  const llvm::Triple::ArchType machine = arch.GetMachine();
+
+  // Integer return type.
----------------
wangleiat wrote:

it's done.

https://github.com/llvm/llvm-project/pull/114742


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