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> ®s) { 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> ®s) { 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 } 281