lldb/source/Target/ABI.cpp

   1 //===-- ABI.cpp -----------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "lldb/Target/ABI.h"
  10 #include "lldb/Core/PluginManager.h"
  11 #include "lldb/Core/Value.h"
  12 #include "lldb/Core/ValueObjectConstResult.h"
  13 #include "lldb/Expression/ExpressionVariable.h"
  14 #include "lldb/Symbol/CompilerType.h"
  15 #include "lldb/Symbol/TypeSystem.h"
  16 #include "lldb/Target/Target.h"
  17 #include "lldb/Target/Thread.h"
  18 #include "lldb/Utility/LLDBLog.h"
  19 #include "lldb/Utility/Log.h"
  20 #include "llvm/MC/TargetRegistry.h"
  21 #include <cctype>
  22
  23 using namespace lldb;
  24 using namespace lldb_private;
  25
  26 ABISP
  27 ABI::FindPlugin(lldb::ProcessSP process_sp, const ArchSpec &arch) {
  28   ABISP abi_sp;
  29   ABICreateInstance create_callback;
  30
  31   for (uint32_t idx = 0;
  32        (create_callback = PluginManager::GetABICreateCallbackAtIndex(idx)) !=
  33        nullptr;
  34        ++idx) {
  35     abi_sp = create_callback(process_sp, arch);
  36
  37     if (abi_sp)
  38       return abi_sp;
  39   }
  40   abi_sp.reset();
  41   return abi_sp;
  42 }
  43
  44 ABI::~ABI() = default;
  45
  46 bool RegInfoBasedABI::GetRegisterInfoByName(llvm::StringRef name,
  47                                             RegisterInfo &info) {
  48   uint32_t count = 0;
  49   const RegisterInfo *register_info_array = GetRegisterInfoArray(count);
  50   if (register_info_array) {
  51     uint32_t i;
  52     for (i = 0; i < count; ++i) {
  53       const char *reg_name = register_info_array[i].name;
  54       if (reg_name == name) {
  55         info = register_info_array[i];
  56         return true;
  57       }
  58     }
  59     for (i = 0; i < count; ++i) {
  60       const char *reg_alt_name = register_info_array[i].alt_name;
  61       if (reg_alt_name == name) {
  62         info = register_info_array[i];
  63         return true;
  64       }
  65     }
  66   }
  67   return false;
  68 }
  69
  70 ValueObjectSP ABI::GetReturnValueObject(Thread &thread, CompilerType &ast_type,
  71                                         bool persistent) const {
  72   if (!ast_type.IsValid())
  73     return ValueObjectSP();
  74
  75   ValueObjectSP return_valobj_sp;
  76
  77   return_valobj_sp = GetReturnValueObjectImpl(thread, ast_type);
  78   if (!return_valobj_sp)
  79     return return_valobj_sp;
  80
  81   // Now turn this into a persistent variable.
  82   // FIXME: This code is duplicated from Target::EvaluateExpression, and it is
  83   // used in similar form in a couple
  84   // of other places.  Figure out the correct Create function to do all this
  85   // work.
  86
  87   if (persistent) {
  88     Target &target = *thread.CalculateTarget();
  89     PersistentExpressionState *persistent_expression_state =
  90         target.GetPersistentExpressionStateForLanguage(
  91             ast_type.GetMinimumLanguage());
  92
  93     if (!persistent_expression_state)
  94       return {};
  95
  96     ConstString persistent_variable_name =
  97         persistent_expression_state->GetNextPersistentVariableName();
  98
  99     lldb::ValueObjectSP const_valobj_sp;
 100
 101     // Check in case our value is already a constant value
 102     if (return_valobj_sp->GetIsConstant()) {
 103       const_valobj_sp = return_valobj_sp;
 104       const_valobj_sp->SetName(persistent_variable_name);
 105     } else
 106       const_valobj_sp =
 107           return_valobj_sp->CreateConstantValue(persistent_variable_name);
 108
 109     lldb::ValueObjectSP live_valobj_sp = return_valobj_sp;
 110
 111     return_valobj_sp = const_valobj_sp;
 112
 113     ExpressionVariableSP expr_variable_sp(
 114         persistent_expression_state->CreatePersistentVariable(
 115             return_valobj_sp));
 116
 117     assert(expr_variable_sp);
 118
 119     // Set flags and live data as appropriate
 120
 121     const Value &result_value = live_valobj_sp->GetValue();
 122
 123     switch (result_value.GetValueType()) {
 124     case Value::ValueType::Invalid:
 125       return {};
 126     case Value::ValueType::HostAddress:
 127     case Value::ValueType::FileAddress:
 128       // we odon't do anything with these for now
 129       break;
 130     case Value::ValueType::Scalar:
 131       expr_variable_sp->m_flags |=
 132           ExpressionVariable::EVIsFreezeDried;
 133       expr_variable_sp->m_flags |=
 134           ExpressionVariable::EVIsLLDBAllocated;
 135       expr_variable_sp->m_flags |=
 136           ExpressionVariable::EVNeedsAllocation;
 137       break;
 138     case Value::ValueType::LoadAddress:
 139       expr_variable_sp->m_live_sp = live_valobj_sp;
 140       expr_variable_sp->m_flags |=
 141           ExpressionVariable::EVIsProgramReference;
 142       break;
 143     }
 144
 145     return_valobj_sp = expr_variable_sp->GetValueObject();
 146   }
 147   return return_valobj_sp;
 148 }
 149
 150 ValueObjectSP ABI::GetReturnValueObject(Thread &thread, llvm::Type &ast_type,
 151                                         bool persistent) const {
 152   ValueObjectSP return_valobj_sp;
 153   return_valobj_sp = GetReturnValueObjectImpl(thread, ast_type);
 154   return return_valobj_sp;
 155 }
 156
 157 // specialized to work with llvm IR types
 158 //
 159 // for now we will specify a default implementation so that we don't need to
 160 // modify other ABIs
 161 lldb::ValueObjectSP ABI::GetReturnValueObjectImpl(Thread &thread,
 162                                                   llvm::Type &ir_type) const {
 163   ValueObjectSP return_valobj_sp;
 164
 165   /* this is a dummy and will only be called if an ABI does not override this */
 166
 167   return return_valobj_sp;
 168 }
 169
 170 bool ABI::PrepareTrivialCall(Thread &thread, lldb::addr_t sp,
 171                              lldb::addr_t functionAddress,
 172                              lldb::addr_t returnAddress, llvm::Type &returntype,
 173                              llvm::ArrayRef<ABI::CallArgument> args) const {
 174   // dummy prepare trivial call
 175   llvm_unreachable("Should never get here!");
 176 }
 177
 178 bool ABI::GetFallbackRegisterLocation(
 179     const RegisterInfo *reg_info,
 180     UnwindPlan::Row::RegisterLocation &unwind_regloc) {
 181   // Did the UnwindPlan fail to give us the caller's stack pointer? The stack
 182   // pointer is defined to be the same as THIS frame's CFA, so return the CFA
 183   // value as the caller's stack pointer.  This is true on x86-32/x86-64 at
 184   // least.
 185   if (reg_info->kinds[eRegisterKindGeneric] == LLDB_REGNUM_GENERIC_SP) {
 186     unwind_regloc.SetIsCFAPlusOffset(0);
 187     return true;
 188   }
 189
 190   // If a volatile register is being requested, we don't want to forward the
 191   // next frame's register contents up the stack -- the register is not
 192   // retrievable at this frame.
 193   if (RegisterIsVolatile(reg_info)) {
 194     unwind_regloc.SetUndefined();
 195     return true;
 196   }
 197
 198   return false;
 199 }
 200
 201 std::unique_ptr<llvm::MCRegisterInfo> ABI::MakeMCRegisterInfo(const ArchSpec &arch) {
 202   std::string triple = arch.GetTriple().getTriple();
 203   std::string lookup_error;
 204   const llvm::Target *target =
 205       llvm::TargetRegistry::lookupTarget(triple, lookup_error);
 206   if (!target) {
 207     LLDB_LOG(GetLog(LLDBLog::Process),
 208              "Failed to create an llvm target for {0}: {1}", triple,
 209              lookup_error);
 210     return nullptr;
 211   }
 212   std::unique_ptr<llvm::MCRegisterInfo> info_up(
 213       target->createMCRegInfo(triple));
 214   assert(info_up);
 215   return info_up;
 216 }
 217
 218 void RegInfoBasedABI::AugmentRegisterInfo(
 219     std::vector<DynamicRegisterInfo::Register> &regs) {
 220   for (DynamicRegisterInfo::Register &info : regs) {
 221     if (info.regnum_ehframe != LLDB_INVALID_REGNUM &&
 222         info.regnum_dwarf != LLDB_INVALID_REGNUM)
 223       continue;
 224
 225     RegisterInfo abi_info;
 226     if (!GetRegisterInfoByName(info.name.GetStringRef(), abi_info))
 227       continue;
 228
 229     if (info.regnum_ehframe == LLDB_INVALID_REGNUM)
 230       info.regnum_ehframe = abi_info.kinds[eRegisterKindEHFrame];
 231     if (info.regnum_dwarf == LLDB_INVALID_REGNUM)
 232       info.regnum_dwarf = abi_info.kinds[eRegisterKindDWARF];
 233     if (info.regnum_generic == LLDB_INVALID_REGNUM)
 234       info.regnum_generic = abi_info.kinds[eRegisterKindGeneric];
 235   }
 236 }
 237
 238 void MCBasedABI::AugmentRegisterInfo(
 239     std::vector<DynamicRegisterInfo::Register> &regs) {
 240   for (DynamicRegisterInfo::Register &info : regs) {
 241     uint32_t eh, dwarf;
 242     std::tie(eh, dwarf) = GetEHAndDWARFNums(info.name.GetStringRef());
 243
 244     if (info.regnum_ehframe == LLDB_INVALID_REGNUM)
 245       info.regnum_ehframe = eh;
 246     if (info.regnum_dwarf == LLDB_INVALID_REGNUM)
 247       info.regnum_dwarf = dwarf;
 248     if (info.regnum_generic == LLDB_INVALID_REGNUM)
 249       info.regnum_generic = GetGenericNum(info.name.GetStringRef());
 250   }
 251 }
 252
 253 std::pair<uint32_t, uint32_t>
 254 MCBasedABI::GetEHAndDWARFNums(llvm::StringRef name) {
 255   std::string mc_name = GetMCName(name.str());
 256   for (char &c : mc_name)
 257     c = std::toupper(c);
 258   int eh = -1;
 259   int dwarf = -1;
 260   for (unsigned reg = 0; reg < m_mc_register_info_up->getNumRegs(); ++reg) {
 261     if (m_mc_register_info_up->getName(reg) == mc_name) {
 262       eh = m_mc_register_info_up->getDwarfRegNum(reg, /*isEH=*/true);
 263       dwarf = m_mc_register_info_up->getDwarfRegNum(reg, /*isEH=*/false);
 264       break;
 265     }
 266   }
 267   return std::pair<uint32_t, uint32_t>(eh == -1 ? LLDB_INVALID_REGNUM : eh,
 268                                        dwarf == -1 ? LLDB_INVALID_REGNUM
 269                                                    : dwarf);
 270 }
 271
 272 void MCBasedABI::MapRegisterName(std::string &name, llvm::StringRef from_prefix,
 273                                  llvm::StringRef to_prefix) {
 274   llvm::StringRef name_ref = name;
 275   if (!name_ref.consume_front(from_prefix))
 276     return;
 277   uint64_t _;
 278   if (name_ref.empty() || to_integer(name_ref, _, 10))
 279     name = (to_prefix + name_ref).str();
 280 }