| //===-- ExecutionContext.h --------------------------------------*- C++ -*-===// |
| // |
| // 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 |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef liblldb_ExecutionContext_h_ |
| #define liblldb_ExecutionContext_h_ |
| |
| #include <mutex> |
| |
| #include "lldb/Target/StackID.h" |
| #include "lldb/lldb-private.h" |
| |
| namespace lldb_private { |
| |
| //===----------------------------------------------------------------------===// |
| /// Execution context objects refer to objects in the execution of the program |
| /// that is being debugged. The consist of one or more of the following |
| /// objects: target, process, thread, and frame. Many objects in the debugger |
| /// need to track different executions contexts. For example, a local function |
| /// variable might have an execution context that refers to a stack frame. A |
| /// global or static variable might refer to a target since a stack frame |
| /// isn't required in order to evaluate a global or static variable (a process |
| /// isn't necessarily needed for a global variable since we might be able to |
| /// read the variable value from a data section in one of the object files in |
| /// a target). There are two types of objects that hold onto execution |
| /// contexts: ExecutionContextRef and ExecutionContext. Both of these objects |
| /// are described below. |
| /// |
| /// Not all objects in an ExecutionContext objects will be valid. If you want |
| /// to refer strongly (ExecutionContext) or weakly (ExecutionContextRef) to a |
| /// process, then only the process and target references will be valid. For |
| /// threads, only the thread, process and target references will be filled in. |
| /// For frames, all of the objects will be filled in. |
| /// |
| /// These classes are designed to be used as baton objects that get passed to |
| /// a wide variety of functions that require execution contexts. |
| //===----------------------------------------------------------------------===// |
| |
| /// \class ExecutionContextRef ExecutionContext.h |
| /// "lldb/Target/ExecutionContext.h" |
| /// A class that holds a weak reference to an execution context. |
| /// |
| /// ExecutionContextRef objects are designed to hold onto an execution context |
| /// that might change over time. For example, if an object wants to refer to a |
| /// stack frame, it should hold onto an ExecutionContextRef to a frame object. |
| /// The backing object that represents the stack frame might change over time |
| /// and instances of this object can track the logical object that refers to a |
| /// frame even if it does change. |
| /// |
| /// These objects also don't keep execution objects around longer than they |
| /// should since they use weak pointers. For example if an object refers to a |
| /// stack frame and a stack frame is no longer in a thread, then a |
| /// ExecutionContextRef object that refers to that frame will not be able to |
| /// get a shared pointer to those objects since they are no longer around. |
| /// |
| /// ExecutionContextRef objects can also be used as objects in classes that |
| /// want to track a "previous execution context". Since the weak references to |
| /// the execution objects (target, process, thread and frame) don't keep these |
| /// objects around, they are safe to keep around. |
| /// |
| /// The general rule of thumb is all long lived objects that want to refer to |
| /// execution contexts should use ExecutionContextRef objects. The |
| /// ExecutionContext class is used to temporarily get shared pointers to any |
| /// execution context objects that are still around so they are guaranteed to |
| /// exist during a function that requires the objects. ExecutionContext |
| /// objects should NOT be used for long term storage since they will keep |
| /// objects alive with extra shared pointer references to these objects. |
| class ExecutionContextRef { |
| public: |
| /// Default Constructor. |
| ExecutionContextRef(); |
| |
| /// Copy Constructor. |
| ExecutionContextRef(const ExecutionContextRef &rhs); |
| |
| /// Construct using an ExecutionContext object that might be nullptr. |
| /// |
| /// If \a exe_ctx_ptr is valid, then make weak references to any valid |
| /// objects in the ExecutionContext, otherwise no weak references to any |
| /// execution context objects will be made. |
| ExecutionContextRef(const ExecutionContext *exe_ctx_ptr); |
| |
| /// Construct using an ExecutionContext object. |
| /// |
| /// Make weak references to any valid objects in the ExecutionContext. |
| ExecutionContextRef(const ExecutionContext &exe_ctx); |
| |
| /// Construct using the target and all the selected items inside of it (the |
| /// process and its selected thread, and the thread's selected frame). If |
| /// there is no selected thread, default to the first thread If there is no |
| /// selected frame, default to the first frame. |
| ExecutionContextRef(Target *target, bool adopt_selected); |
| |
| /// Construct using an execution context scope. |
| /// |
| /// If the ExecutionContextScope object is valid and refers to a frame, make |
| /// weak references too the frame, thread, process and target. If the |
| /// ExecutionContextScope object is valid and refers to a thread, make weak |
| /// references too the thread, process and target. If the |
| /// ExecutionContextScope object is valid and refers to a process, make weak |
| /// references too the process and target. If the ExecutionContextScope |
| /// object is valid and refers to a target, make weak references too the |
| /// target. |
| ExecutionContextRef(ExecutionContextScope *exe_scope); |
| |
| /// Construct using an execution context scope. |
| /// |
| /// If the ExecutionContextScope object refers to a frame, make weak |
| /// references too the frame, thread, process and target. If the |
| /// ExecutionContextScope object refers to a thread, make weak references |
| /// too the thread, process and target. If the ExecutionContextScope object |
| /// refers to a process, make weak references too the process and target. If |
| /// the ExecutionContextScope object refers to a target, make weak |
| /// references too the target. |
| ExecutionContextRef(ExecutionContextScope &exe_scope); |
| |
| ~ExecutionContextRef(); |
| |
| /// Assignment operator |
| /// |
| /// Copy all weak references in \a rhs. |
| ExecutionContextRef &operator=(const ExecutionContextRef &rhs); |
| |
| /// Assignment operator from a ExecutionContext |
| /// |
| /// Make weak references to any strongly referenced objects in \a exe_ctx. |
| ExecutionContextRef &operator=(const ExecutionContext &exe_ctx); |
| |
| /// Clear the object's state. |
| /// |
| /// Sets the process and thread to nullptr, and the frame index to an |
| /// invalid value. |
| void Clear(); |
| |
| /// Set accessor that creates a weak reference to the target referenced in |
| /// \a target_sp. |
| /// |
| /// If \a target_sp is valid this object will create a weak reference to |
| /// that object, otherwise any previous target weak reference contained in |
| /// this object will be reset. |
| /// |
| /// Only the weak reference to the target will be updated, no other weak |
| /// references will be modified. If you want this execution context to make |
| /// a weak reference to the target's process, use the |
| /// ExecutionContextRef::SetContext() functions. |
| /// |
| /// \see ExecutionContextRef::SetContext(const lldb::TargetSP &, bool) |
| void SetTargetSP(const lldb::TargetSP &target_sp); |
| |
| /// Set accessor that creates a weak reference to the process referenced in |
| /// \a process_sp. |
| /// |
| /// If \a process_sp is valid this object will create a weak reference to |
| /// that object, otherwise any previous process weak reference contained in |
| /// this object will be reset. |
| /// |
| /// Only the weak reference to the process will be updated, no other weak |
| /// references will be modified. If you want this execution context to make |
| /// a weak reference to the target, use the |
| /// ExecutionContextRef::SetContext() functions. |
| /// |
| /// \see ExecutionContextRef::SetContext(const lldb::ProcessSP &) |
| void SetProcessSP(const lldb::ProcessSP &process_sp); |
| |
| /// Set accessor that creates a weak reference to the thread referenced in |
| /// \a thread_sp. |
| /// |
| /// If \a thread_sp is valid this object will create a weak reference to |
| /// that object, otherwise any previous thread weak reference contained in |
| /// this object will be reset. |
| /// |
| /// Only the weak reference to the thread will be updated, no other weak |
| /// references will be modified. If you want this execution context to make |
| /// a weak reference to the thread's process and target, use the |
| /// ExecutionContextRef::SetContext() functions. |
| /// |
| /// \see ExecutionContextRef::SetContext(const lldb::ThreadSP &) |
| void SetThreadSP(const lldb::ThreadSP &thread_sp); |
| |
| /// Set accessor that creates a weak reference to the frame referenced in \a |
| /// frame_sp. |
| /// |
| /// If \a frame_sp is valid this object will create a weak reference to that |
| /// object, otherwise any previous frame weak reference contained in this |
| /// object will be reset. |
| /// |
| /// Only the weak reference to the frame will be updated, no other weak |
| /// references will be modified. If you want this execution context to make |
| /// a weak reference to the frame's thread, process and target, use the |
| /// ExecutionContextRef::SetContext() functions. |
| /// |
| /// \see ExecutionContextRef::SetContext(const lldb::StackFrameSP &) |
| void SetFrameSP(const lldb::StackFrameSP &frame_sp); |
| |
| void SetTargetPtr(Target *target, bool adopt_selected); |
| |
| void SetProcessPtr(Process *process); |
| |
| void SetThreadPtr(Thread *thread); |
| |
| void SetFramePtr(StackFrame *frame); |
| |
| /// Get accessor that creates a strong reference from the weak target |
| /// reference contained in this object. |
| /// |
| /// \returns |
| /// A shared pointer to a target that is not guaranteed to be valid. |
| lldb::TargetSP GetTargetSP() const; |
| |
| /// Get accessor that creates a strong reference from the weak process |
| /// reference contained in this object. |
| /// |
| /// \returns |
| /// A shared pointer to a process that is not guaranteed to be valid. |
| lldb::ProcessSP GetProcessSP() const; |
| |
| /// Get accessor that creates a strong reference from the weak thread |
| /// reference contained in this object. |
| /// |
| /// \returns |
| /// A shared pointer to a thread that is not guaranteed to be valid. |
| lldb::ThreadSP GetThreadSP() const; |
| |
| /// Get accessor that creates a strong reference from the weak frame |
| /// reference contained in this object. |
| /// |
| /// \returns |
| /// A shared pointer to a frame that is not guaranteed to be valid. |
| lldb::StackFrameSP GetFrameSP() const; |
| |
| /// Create an ExecutionContext object from this object. |
| /// |
| /// Create strong references to any execution context objects that are still |
| /// valid. Any of the returned shared pointers in the ExecutionContext |
| /// objects is not guaranteed to be valid. \returns |
| /// An execution context object that has strong references to |
| /// any valid weak references in this object. |
| ExecutionContext Lock(bool thread_and_frame_only_if_stopped) const; |
| |
| /// Returns true if this object has a weak reference to a thread. The return |
| /// value is only an indication of whether this object has a weak reference |
| /// and does not indicate whether the weak reference is valid or not. |
| bool HasThreadRef() const { return m_tid != LLDB_INVALID_THREAD_ID; } |
| |
| /// Returns true if this object has a weak reference to a frame. The return |
| /// value is only an indication of whether this object has a weak reference |
| /// and does not indicate whether the weak reference is valid or not. |
| bool HasFrameRef() const { return m_stack_id.IsValid(); } |
| |
| void ClearThread() { |
| m_thread_wp.reset(); |
| m_tid = LLDB_INVALID_THREAD_ID; |
| } |
| |
| void ClearFrame() { m_stack_id.Clear(); } |
| |
| protected: |
| // Member variables |
| lldb::TargetWP m_target_wp; ///< A weak reference to a target |
| lldb::ProcessWP m_process_wp; ///< A weak reference to a process |
| mutable lldb::ThreadWP m_thread_wp; ///< A weak reference to a thread |
| lldb::tid_t m_tid; ///< The thread ID that this object refers to in case the |
| ///backing object changes |
| StackID m_stack_id; ///< The stack ID that this object refers to in case the |
| ///backing object changes |
| }; |
| |
| /// \class ExecutionContext ExecutionContext.h |
| /// "lldb/Target/ExecutionContext.h" |
| /// A class that contains an execution context. |
| /// |
| /// This baton object can be passed into any function that requires a context |
| /// that specifies a target, process, thread and frame. These objects are |
| /// designed to be used for short term execution context object storage while |
| /// a function might be trying to evaluate something that requires a thread or |
| /// frame. ExecutionContextRef objects can be used to initialize one of these |
| /// objects to turn the weak execution context object references to the |
| /// target, process, thread and frame into strong references (shared pointers) |
| /// so that functions can guarantee that these objects won't go away in the |
| /// middle of a function. |
| /// |
| /// ExecutionContext objects should be used as short lived objects (typically |
| /// on the stack) in order to lock down an execution context for local use and |
| /// for passing down to other functions that also require specific contexts. |
| /// They should NOT be used for long term storage, for long term storage use |
| /// ExecutionContextRef objects. |
| class ExecutionContext { |
| public: |
| /// Default Constructor. |
| ExecutionContext(); |
| |
| // Copy constructor |
| ExecutionContext(const ExecutionContext &rhs); |
| |
| // Adopt the target and optionally its current context. |
| ExecutionContext(Target *t, bool fill_current_process_thread_frame = true); |
| |
| // Create execution contexts from shared pointers |
| ExecutionContext(const lldb::TargetSP &target_sp, bool get_process); |
| ExecutionContext(const lldb::ProcessSP &process_sp); |
| ExecutionContext(const lldb::ThreadSP &thread_sp); |
| ExecutionContext(const lldb::StackFrameSP &frame_sp); |
| |
| // Create execution contexts from weak pointers |
| ExecutionContext(const lldb::TargetWP &target_wp, bool get_process); |
| ExecutionContext(const lldb::ProcessWP &process_wp); |
| ExecutionContext(const lldb::ThreadWP &thread_wp); |
| ExecutionContext(const lldb::StackFrameWP &frame_wp); |
| ExecutionContext(const ExecutionContextRef &exe_ctx_ref); |
| ExecutionContext(const ExecutionContextRef *exe_ctx_ref, |
| bool thread_and_frame_only_if_stopped = false); |
| |
| // These two variants take in a locker, and grab the target, lock the API |
| // mutex into locker, then fill in the rest of the shared pointers. |
| ExecutionContext(const ExecutionContextRef &exe_ctx_ref, |
| std::unique_lock<std::recursive_mutex> &locker); |
| ExecutionContext(const ExecutionContextRef *exe_ctx_ref, |
| std::unique_lock<std::recursive_mutex> &locker); |
| // Create execution contexts from execution context scopes |
| ExecutionContext(ExecutionContextScope *exe_scope); |
| ExecutionContext(ExecutionContextScope &exe_scope); |
| |
| /// Construct with process, thread, and frame index. |
| /// |
| /// Initialize with process \a p, thread \a t, and frame index \a f. |
| /// |
| /// \param[in] process |
| /// The process for this execution context. |
| /// |
| /// \param[in] thread |
| /// The thread for this execution context. |
| /// |
| /// \param[in] frame |
| /// The frame index for this execution context. |
| ExecutionContext(Process *process, Thread *thread = nullptr, |
| StackFrame *frame = nullptr); |
| |
| ~ExecutionContext(); |
| |
| ExecutionContext &operator=(const ExecutionContext &rhs); |
| |
| bool operator==(const ExecutionContext &rhs) const; |
| |
| bool operator!=(const ExecutionContext &rhs) const; |
| |
| /// Clear the object's state. |
| /// |
| /// Sets the process and thread to nullptr, and the frame index to an |
| /// invalid value. |
| void Clear(); |
| |
| RegisterContext *GetRegisterContext() const; |
| |
| ExecutionContextScope *GetBestExecutionContextScope() const; |
| |
| uint32_t GetAddressByteSize() const; |
| |
| lldb::ByteOrder GetByteOrder() const; |
| |
| /// Returns a pointer to the target object. |
| /// |
| /// The returned pointer might be nullptr. Calling HasTargetScope(), |
| /// HasProcessScope(), HasThreadScope(), or HasFrameScope() can help to pre- |
| /// validate this pointer so that this accessor can freely be used without |
| /// having to check for nullptr each time. |
| /// |
| /// \see ExecutionContext::HasTargetScope() const @see |
| /// ExecutionContext::HasProcessScope() const @see |
| /// ExecutionContext::HasThreadScope() const @see |
| /// ExecutionContext::HasFrameScope() const |
| Target *GetTargetPtr() const; |
| |
| /// Returns a pointer to the process object. |
| /// |
| /// The returned pointer might be nullptr. Calling HasProcessScope(), |
| /// HasThreadScope(), or HasFrameScope() can help to pre-validate this |
| /// pointer so that this accessor can freely be used without having to check |
| /// for nullptr each time. |
| /// |
| /// \see ExecutionContext::HasProcessScope() const @see |
| /// ExecutionContext::HasThreadScope() const @see |
| /// ExecutionContext::HasFrameScope() const |
| Process *GetProcessPtr() const; |
| |
| /// Returns a pointer to the thread object. |
| /// |
| /// The returned pointer might be nullptr. Calling HasThreadScope() or |
| /// HasFrameScope() can help to pre-validate this pointer so that this |
| /// accessor can freely be used without having to check for nullptr each |
| /// time. |
| /// |
| /// \see ExecutionContext::HasThreadScope() const @see |
| /// ExecutionContext::HasFrameScope() const |
| Thread *GetThreadPtr() const { return m_thread_sp.get(); } |
| |
| /// Returns a pointer to the frame object. |
| /// |
| /// The returned pointer might be nullptr. Calling HasFrameScope(), can help |
| /// to pre-validate this pointer so that this accessor can freely be used |
| /// without having to check for nullptr each time. |
| /// |
| /// \see ExecutionContext::HasFrameScope() const |
| StackFrame *GetFramePtr() const { return m_frame_sp.get(); } |
| |
| /// Returns a reference to the target object. |
| /// |
| /// Clients should call HasTargetScope(), HasProcessScope(), |
| /// HasThreadScope(), or HasFrameScope() prior to calling this function to |
| /// ensure that this ExecutionContext object contains a valid target. |
| /// |
| /// \see ExecutionContext::HasTargetScope() const @see |
| /// ExecutionContext::HasProcessScope() const @see |
| /// ExecutionContext::HasThreadScope() const @see |
| /// ExecutionContext::HasFrameScope() const |
| Target &GetTargetRef() const; |
| |
| /// Returns a reference to the process object. |
| /// |
| /// Clients should call HasProcessScope(), HasThreadScope(), or |
| /// HasFrameScope() prior to calling this function to ensure that this |
| /// ExecutionContext object contains a valid target. |
| /// |
| /// \see ExecutionContext::HasProcessScope() const @see |
| /// ExecutionContext::HasThreadScope() const @see |
| /// ExecutionContext::HasFrameScope() const |
| Process &GetProcessRef() const; |
| |
| /// Returns a reference to the thread object. |
| /// |
| /// Clients should call HasThreadScope(), or HasFrameScope() prior to |
| /// calling this function to ensure that this ExecutionContext object |
| /// contains a valid target. |
| /// |
| /// \see ExecutionContext::HasThreadScope() const @see |
| /// ExecutionContext::HasFrameScope() const |
| Thread &GetThreadRef() const; |
| |
| /// Returns a reference to the thread object. |
| /// |
| /// Clients should call HasFrameScope() prior to calling this function to |
| /// ensure that this ExecutionContext object contains a valid target. |
| /// |
| /// \see ExecutionContext::HasFrameScope() const |
| StackFrame &GetFrameRef() const; |
| |
| /// Get accessor to get the target shared pointer. |
| /// |
| /// The returned shared pointer is not guaranteed to be valid. |
| const lldb::TargetSP &GetTargetSP() const { return m_target_sp; } |
| |
| /// Get accessor to get the process shared pointer. |
| /// |
| /// The returned shared pointer is not guaranteed to be valid. |
| const lldb::ProcessSP &GetProcessSP() const { return m_process_sp; } |
| |
| /// Get accessor to get the thread shared pointer. |
| /// |
| /// The returned shared pointer is not guaranteed to be valid. |
| const lldb::ThreadSP &GetThreadSP() const { return m_thread_sp; } |
| |
| /// Get accessor to get the frame shared pointer. |
| /// |
| /// The returned shared pointer is not guaranteed to be valid. |
| const lldb::StackFrameSP &GetFrameSP() const { return m_frame_sp; } |
| |
| /// Set accessor to set only the target shared pointer. |
| void SetTargetSP(const lldb::TargetSP &target_sp); |
| |
| /// Set accessor to set only the process shared pointer. |
| void SetProcessSP(const lldb::ProcessSP &process_sp); |
| |
| /// Set accessor to set only the thread shared pointer. |
| void SetThreadSP(const lldb::ThreadSP &thread_sp); |
| |
| /// Set accessor to set only the frame shared pointer. |
| void SetFrameSP(const lldb::StackFrameSP &frame_sp); |
| |
| /// Set accessor to set only the target shared pointer from a target |
| /// pointer. |
| void SetTargetPtr(Target *target); |
| |
| /// Set accessor to set only the process shared pointer from a process |
| /// pointer. |
| void SetProcessPtr(Process *process); |
| |
| /// Set accessor to set only the thread shared pointer from a thread |
| /// pointer. |
| void SetThreadPtr(Thread *thread); |
| |
| /// Set accessor to set only the frame shared pointer from a frame pointer. |
| void SetFramePtr(StackFrame *frame); |
| |
| // Set the execution context using a target shared pointer. |
| // |
| // If "target_sp" is valid, sets the target context to match and if |
| // "get_process" is true, sets the process shared pointer if the target |
| // currently has a process. |
| void SetContext(const lldb::TargetSP &target_sp, bool get_process); |
| |
| // Set the execution context using a process shared pointer. |
| // |
| // If "process_sp" is valid, then set the process and target in this context. |
| // Thread and frame contexts will be cleared. If "process_sp" is not valid, |
| // all shared pointers are reset. |
| void SetContext(const lldb::ProcessSP &process_sp); |
| |
| // Set the execution context using a thread shared pointer. |
| // |
| // If "thread_sp" is valid, then set the thread, process and target in this |
| // context. The frame context will be cleared. If "thread_sp" is not valid, |
| // all shared pointers are reset. |
| void SetContext(const lldb::ThreadSP &thread_sp); |
| |
| // Set the execution context using a frame shared pointer. |
| // |
| // If "frame_sp" is valid, then set the frame, thread, process and target in |
| // this context If "frame_sp" is not valid, all shared pointers are reset. |
| void SetContext(const lldb::StackFrameSP &frame_sp); |
| |
| /// Returns true the ExecutionContext object contains a valid target. |
| /// |
| /// This function can be called after initializing an ExecutionContext |
| /// object, and if it returns true, calls to GetTargetPtr() and |
| /// GetTargetRef() do not need to be checked for validity. |
| bool HasTargetScope() const; |
| |
| /// Returns true the ExecutionContext object contains a valid target and |
| /// process. |
| /// |
| /// This function can be called after initializing an ExecutionContext |
| /// object, and if it returns true, calls to GetTargetPtr() and |
| /// GetTargetRef(), GetProcessPtr(), and GetProcessRef(), do not need to be |
| /// checked for validity. |
| bool HasProcessScope() const; |
| |
| /// Returns true the ExecutionContext object contains a valid target, |
| /// process, and thread. |
| /// |
| /// This function can be called after initializing an ExecutionContext |
| /// object, and if it returns true, calls to GetTargetPtr(), GetTargetRef(), |
| /// GetProcessPtr(), GetProcessRef(), GetThreadPtr(), and GetThreadRef() do |
| /// not need to be checked for validity. |
| bool HasThreadScope() const; |
| |
| /// Returns true the ExecutionContext object contains a valid target, |
| /// process, thread and frame. |
| /// |
| /// This function can be called after initializing an ExecutionContext |
| /// object, and if it returns true, calls to GetTargetPtr(), GetTargetRef(), |
| /// GetProcessPtr(), GetProcessRef(), GetThreadPtr(), GetThreadRef(), |
| /// GetFramePtr(), and GetFrameRef() do not need to be checked for validity. |
| bool HasFrameScope() const; |
| |
| protected: |
| // Member variables |
| lldb::TargetSP m_target_sp; ///< The target that owns the process/thread/frame |
| lldb::ProcessSP m_process_sp; ///< The process that owns the thread/frame |
| lldb::ThreadSP m_thread_sp; ///< The thread that owns the frame |
| lldb::StackFrameSP m_frame_sp; ///< The stack frame in thread. |
| }; |
| |
| } // namespace lldb_private |
| |
| #endif // liblldb_ExecutionContext_h_ |