1 //===------------------- ABISysV_i386.h -------------------------*- C++ -*-===// 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 #ifndef liblldb_ABISysV_i386_h_ 10 #define liblldb_ABISysV_i386_h_ 11 12 #include "lldb/Target/ABI.h" 13 #include "lldb/lldb-private.h" 14 15 class ABISysV_i386 : public lldb_private::ABI { 16 public: 17 ~ABISysV_i386() override = default; 18 GetRedZoneSize()19 size_t GetRedZoneSize() const override { 20 return 0; // There is no red zone for i386 Architecture 21 } 22 23 bool PrepareTrivialCall(lldb_private::Thread &thread, lldb::addr_t sp, 24 lldb::addr_t functionAddress, 25 lldb::addr_t returnAddress, 26 llvm::ArrayRef<lldb::addr_t> args) const override; 27 28 bool GetArgumentValues(lldb_private::Thread &thread, 29 lldb_private::ValueList &values) const override; 30 31 lldb_private::Status 32 SetReturnValueObject(lldb::StackFrameSP &frame_sp, 33 lldb::ValueObjectSP &new_value) override; 34 35 lldb::ValueObjectSP 36 GetReturnValueObjectImpl(lldb_private::Thread &thread, 37 lldb_private::CompilerType &type) const override; 38 39 bool 40 CreateFunctionEntryUnwindPlan(lldb_private::UnwindPlan &unwind_plan) override; 41 42 bool CreateDefaultUnwindPlan(lldb_private::UnwindPlan &unwind_plan) override; 43 RegisterIsVolatile(const lldb_private::RegisterInfo * reg_info)44 bool RegisterIsVolatile(const lldb_private::RegisterInfo *reg_info) override { 45 return !RegisterIsCalleeSaved(reg_info); 46 } 47 48 // The SysV i386 ABI requires that stack frames be 16 byte aligned. 49 // When there is a trap handler on the stack, e.g. _sigtramp in userland 50 // code, we've seen that the stack pointer is often not aligned properly 51 // before the handler is invoked. This means that lldb will stop the unwind 52 // early -- before the function which caused the trap. 53 // 54 // To work around this, we relax that alignment to be just word-size 55 // (4-bytes). 56 // Whitelisting the trap handlers for user space would be easy (_sigtramp) but 57 // in other environments there can be a large number of different functions 58 // involved in async traps. 59 60 // ToDo: When __m256 arguments are passed then stack frames should be 61 // 32 byte aligned. Decide what to do for 32 byte alignment checking CallFrameAddressIsValid(lldb::addr_t cfa)62 bool CallFrameAddressIsValid(lldb::addr_t cfa) override { 63 // Make sure the stack call frame addresses are 4 byte aligned 64 if (cfa & (4ull - 1ull)) 65 return false; // Not 4 byte aligned 66 if (cfa == 0) 67 return false; // Zero is not a valid stack address 68 return true; 69 } 70 CodeAddressIsValid(lldb::addr_t pc)71 bool CodeAddressIsValid(lldb::addr_t pc) override { 72 // Check whether the address is a valid 32 bit address 73 return (pc <= UINT32_MAX); 74 } 75 76 const lldb_private::RegisterInfo * 77 GetRegisterInfoArray(uint32_t &count) override; 78 79 // Static Functions 80 81 static void Initialize(); 82 83 static void Terminate(); 84 85 static lldb::ABISP CreateInstance(lldb::ProcessSP process_sp, const lldb_private::ArchSpec &arch); 86 87 // PluginInterface protocol 88 89 static lldb_private::ConstString GetPluginNameStatic(); 90 91 lldb_private::ConstString GetPluginName() override; 92 GetPluginVersion()93 uint32_t GetPluginVersion() override { return 1; } 94 95 protected: 96 lldb::ValueObjectSP 97 GetReturnValueObjectSimple(lldb_private::Thread &thread, 98 lldb_private::CompilerType &ast_type) const; 99 100 bool RegisterIsCalleeSaved(const lldb_private::RegisterInfo *reg_info); 101 102 private: ABISysV_i386(lldb::ProcessSP process_sp,std::unique_ptr<llvm::MCRegisterInfo> info_up)103 ABISysV_i386(lldb::ProcessSP process_sp, 104 std::unique_ptr<llvm::MCRegisterInfo> info_up) 105 : lldb_private::ABI(std::move(process_sp), std::move(info_up)) { 106 // Call CreateInstance instead. 107 } 108 }; 109 110 #endif // liblldb_ABISysV_i386_h_ 111