Coverage Report

Created: 2022-01-15 10:30

/Users/buildslave/jenkins/workspace/coverage/llvm-project/lldb/include/lldb/Expression/DWARFExpression.h
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//===-- DWARFExpression.h ---------------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLDB_EXPRESSION_DWARFEXPRESSION_H
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#define LLDB_EXPRESSION_DWARFEXPRESSION_H
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#include "lldb/Core/Address.h"
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#include "lldb/Core/Disassembler.h"
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#include "lldb/Utility/DataExtractor.h"
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#include "lldb/Utility/Scalar.h"
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#include "lldb/Utility/Status.h"
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#include "lldb/lldb-private.h"
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#include <functional>
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class DWARFUnit;
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namespace lldb_private {
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/// \class DWARFExpression DWARFExpression.h
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/// "lldb/Expression/DWARFExpression.h" Encapsulates a DWARF location
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/// expression and interprets it.
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///
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/// DWARF location expressions are used in two ways by LLDB.  The first
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/// use is to find entities specified in the debug information, since their
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/// locations are specified in precisely this language.  The second is to
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/// interpret expressions without having to run the target in cases where the
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/// overhead from copying JIT-compiled code into the target is too high or
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/// where the target cannot be run.  This class encapsulates a single DWARF
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/// location expression or a location list and interprets it.
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class DWARFExpression {
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public:
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  DWARFExpression();
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  /// Constructor
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  ///
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  /// \param[in] data
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  ///     A data extractor configured to read the DWARF location expression's
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  ///     bytecode.
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  DWARFExpression(lldb::ModuleSP module, const DataExtractor &data,
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                  const DWARFUnit *dwarf_cu);
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  /// Destructor
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  virtual ~DWARFExpression();
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  /// Print the description of the expression to a stream
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  ///
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  /// \param[in] s
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  ///     The stream to print to.
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  ///
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  /// \param[in] level
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  ///     The level of verbosity to use.
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  ///
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  /// \param[in] location_list_base_addr
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  ///     If this is a location list based expression, this is the
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  ///     address of the object that owns it. NOTE: this value is
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  ///     different from the DWARF version of the location list base
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  ///     address which is compile unit relative. This base address
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  ///     is the address of the object that owns the location list.
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  ///
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  /// \param[in] abi
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  ///     An optional ABI plug-in that can be used to resolve register
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  ///     names.
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  void GetDescription(Stream *s, lldb::DescriptionLevel level,
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                      lldb::addr_t location_list_base_addr, ABI *abi) const;
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  /// Return true if the location expression contains data
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  bool IsValid() const;
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  /// Return true if a location list was provided
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  bool IsLocationList() const;
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  /// Search for a load address in the location list
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  ///
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  /// \param[in] func_load_addr
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  ///     The actual address of the function containing this location list.
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  ///
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  /// \param[in] addr
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  ///     The address to resolve
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  ///
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  /// \return
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  ///     True if IsLocationList() is true and the address was found;
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  ///     false otherwise.
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  //    bool
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  //    LocationListContainsLoadAddress (Process* process, const Address &addr)
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  //    const;
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  //
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  bool LocationListContainsAddress(lldb::addr_t func_load_addr,
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                                   lldb::addr_t addr) const;
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  /// If a location is not a location list, return true if the location
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  /// contains a DW_OP_addr () opcode in the stream that matches \a file_addr.
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  /// If file_addr is LLDB_INVALID_ADDRESS, the this function will return true
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  /// if the variable there is any DW_OP_addr in a location that (yet still is
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  /// NOT a location list). This helps us detect if a variable is a global or
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  /// static variable since there is no other indication from DWARF debug
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  /// info.
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  ///
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  /// \param[in] op_addr_idx
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  ///     The DW_OP_addr index to retrieve in case there is more than
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  ///     one DW_OP_addr opcode in the location byte stream.
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  ///
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  /// \param[out] error
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  ///     If the location stream contains unknown DW_OP opcodes or the
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  ///     data is missing, \a error will be set to \b true.
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  ///
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  /// \return
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  ///     LLDB_INVALID_ADDRESS if the location doesn't contain a
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  ///     DW_OP_addr for \a op_addr_idx, otherwise a valid file address
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  lldb::addr_t GetLocation_DW_OP_addr(uint32_t op_addr_idx, bool &error) const;
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  bool Update_DW_OP_addr(lldb::addr_t file_addr);
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  void UpdateValue(uint64_t const_value, lldb::offset_t const_value_byte_size,
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                   uint8_t addr_byte_size);
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  void SetModule(const lldb::ModuleSP &module) { m_module_wp = module; }
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  bool ContainsThreadLocalStorage() const;
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  bool LinkThreadLocalStorage(
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      lldb::ModuleSP new_module_sp,
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      std::function<lldb::addr_t(lldb::addr_t file_addr)> const
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          &link_address_callback);
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  /// Tells the expression that it refers to a location list.
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  ///
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  /// \param[in] cu_file_addr
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  ///     The base address to use for interpreting relative location list
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  ///     entries.
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  /// \param[in] func_file_addr
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  ///     The file address of the function containing this location list. This
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  ///     address will be used to relocate the location list on the fly (in
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  ///     conjuction with the func_load_addr arguments).
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  void SetLocationListAddresses(lldb::addr_t cu_file_addr,
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                                lldb::addr_t func_file_addr);
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  /// Return the call-frame-info style register kind
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  int GetRegisterKind();
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  /// Set the call-frame-info style register kind
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  ///
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  /// \param[in] reg_kind
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  ///     The register kind.
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  void SetRegisterKind(lldb::RegisterKind reg_kind);
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  /// Wrapper for the static evaluate function that accepts an
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  /// ExecutionContextScope instead of an ExecutionContext and uses member
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  /// variables to populate many operands
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  bool Evaluate(ExecutionContextScope *exe_scope, lldb::addr_t func_load_addr,
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                const Value *initial_value_ptr, const Value *object_address_ptr,
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                Value &result, Status *error_ptr) const;
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  /// Wrapper for the static evaluate function that uses member variables to
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  /// populate many operands
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  bool Evaluate(ExecutionContext *exe_ctx, RegisterContext *reg_ctx,
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                lldb::addr_t loclist_base_load_addr,
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                const Value *initial_value_ptr, const Value *object_address_ptr,
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                Value &result, Status *error_ptr) const;
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  /// Evaluate a DWARF location expression in a particular context
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  ///
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  /// \param[in] exe_ctx
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  ///     The execution context in which to evaluate the location
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  ///     expression.  The location expression may access the target's
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  ///     memory, especially if it comes from the expression parser.
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  ///
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  /// \param[in] opcode_ctx
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  ///     The module which defined the expression.
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  ///
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  /// \param[in] opcodes
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  ///     This is a static method so the opcodes need to be provided
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  ///     explicitly.
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  ///
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  ///  \param[in] reg_ctx
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  ///     An optional parameter which provides a RegisterContext for use
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  ///     when evaluating the expression (i.e. for fetching register values).
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  ///     Normally this will come from the ExecutionContext's StackFrame but
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  ///     in the case where an expression needs to be evaluated while building
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  ///     the stack frame list, this short-cut is available.
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  ///
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  /// \param[in] reg_set
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  ///     The call-frame-info style register kind.
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  ///
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  /// \param[in] initial_value_ptr
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  ///     A value to put on top of the interpreter stack before evaluating
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  ///     the expression, if the expression is parametrized.  Can be NULL.
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  ///
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  /// \param[in] result
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  ///     A value into which the result of evaluating the expression is
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  ///     to be placed.
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  ///
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  /// \param[in] error_ptr
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  ///     If non-NULL, used to report errors in expression evaluation.
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  ///
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  /// \return
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  ///     True on success; false otherwise.  If error_ptr is non-NULL,
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  ///     details of the failure are provided through it.
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  static bool Evaluate(ExecutionContext *exe_ctx, RegisterContext *reg_ctx,
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                       lldb::ModuleSP opcode_ctx, const DataExtractor &opcodes,
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                       const DWARFUnit *dwarf_cu,
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                       const lldb::RegisterKind reg_set,
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                       const Value *initial_value_ptr,
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                       const Value *object_address_ptr, Value &result,
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                       Status *error_ptr);
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  bool GetExpressionData(DataExtractor &data) const {
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    data = m_data;
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    return data.GetByteSize() > 0;
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  }
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  bool DumpLocationForAddress(Stream *s, lldb::DescriptionLevel level,
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                              lldb::addr_t func_load_addr, lldb::addr_t address,
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                              ABI *abi);
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  bool MatchesOperand(StackFrame &frame, const Instruction::Operand &op);
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  llvm::Optional<DataExtractor>
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  GetLocationExpression(lldb::addr_t load_function_start,
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                        lldb::addr_t addr) const;
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private:
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  /// Pretty-prints the location expression to a stream
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  ///
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  /// \param[in] s
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  ///     The stream to use for pretty-printing.
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  ///
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  /// \param[in] data
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  ///     The data extractor.
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  ///
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  /// \param[in] level
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  ///     The level of detail to use in pretty-printing.
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  ///
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  /// \param[in] abi
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  ///     An optional ABI plug-in that can be used to resolve register
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  ///     names.
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  void DumpLocation(Stream *s, const DataExtractor &data,
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                    lldb::DescriptionLevel level, ABI *abi) const;
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  /// Module which defined this expression.
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  lldb::ModuleWP m_module_wp;
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  /// A data extractor capable of reading opcode bytes
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  DataExtractor m_data;
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  /// The DWARF compile unit this expression belongs to. It is used to evaluate
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  /// values indexing into the .debug_addr section (e.g. DW_OP_GNU_addr_index,
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  /// DW_OP_GNU_const_index)
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  const DWARFUnit *m_dwarf_cu = nullptr;
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  /// One of the defines that starts with LLDB_REGKIND_
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  lldb::RegisterKind m_reg_kind = lldb::eRegisterKindDWARF;
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  struct LoclistAddresses {
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    lldb::addr_t cu_file_addr;
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    lldb::addr_t func_file_addr;
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  };
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  llvm::Optional<LoclistAddresses> m_loclist_addresses;
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};
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} // namespace lldb_private
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#endif // LLDB_EXPRESSION_DWARFEXPRESSION_H