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| 1 | +//===- ExecutionContext.h - Execution Context Support *- 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 MLIR_TRACING_EXECUTIONCONTEXT_H |
| 10 | +#define MLIR_TRACING_EXECUTIONCONTEXT_H |
| 11 | + |
| 12 | +#include "mlir/Debug/BreakpointManager.h" |
| 13 | +#include "mlir/IR/Action.h" |
| 14 | +#include "llvm/ADT/SmallVector.h" |
| 15 | + |
| 16 | +namespace mlir { |
| 17 | +namespace tracing { |
| 18 | + |
| 19 | +/// This class is used to keep track of the active actions in the stack. |
| 20 | +/// It provides the current action but also access to the parent entry in the |
| 21 | +/// stack. This allows to keep track of the nested nature in which actions may |
| 22 | +/// be executed. |
| 23 | +struct ActionActiveStack { |
| 24 | +public: |
| 25 | + ActionActiveStack(const ActionActiveStack *parent, const Action &action, |
| 26 | + int depth) |
| 27 | + : parent(parent), action(action), depth(depth) {} |
| 28 | + const ActionActiveStack *getParent() const { return parent; } |
| 29 | + const Action &getAction() const { return action; } |
| 30 | + int getDepth() const { return depth; } |
| 31 | + |
| 32 | +private: |
| 33 | + const ActionActiveStack *parent; |
| 34 | + const Action &action; |
| 35 | + int depth; |
| 36 | +}; |
| 37 | + |
| 38 | +/// The ExecutionContext is the main orchestration of the infrastructure, it |
| 39 | +/// acts as a handler in the MLIRContext for executing an Action. When an action |
| 40 | +/// is dispatched, it'll query its set of Breakpoints managers for a breakpoint |
| 41 | +/// matching this action. If a breakpoint is hit, it passes the action and the |
| 42 | +/// breakpoint information to a callback. The callback is responsible for |
| 43 | +/// controlling the execution of the action through an enum value it returns. |
| 44 | +/// Optionally, observers can be registered to be notified before and after the |
| 45 | +/// callback is executed. |
| 46 | +class ExecutionContext { |
| 47 | +public: |
| 48 | + /// Enum that allows the client of the context to control the execution of the |
| 49 | + /// action. |
| 50 | + /// - Apply: The action is executed. |
| 51 | + /// - Skip: The action is skipped. |
| 52 | + /// - Step: The action is executed and the execution is paused before the next |
| 53 | + /// action, including for nested actions encountered before the |
| 54 | + /// current action finishes. |
| 55 | + /// - Next: The action is executed and the execution is paused after the |
| 56 | + /// current action finishes before the next action. |
| 57 | + /// - Finish: The action is executed and the execution is paused only when we |
| 58 | + /// reach the parent/enclosing operation. If there are no enclosing |
| 59 | + /// operation, the execution continues without stopping. |
| 60 | + enum Control { Apply = 1, Skip = 2, Step = 3, Next = 4, Finish = 5 }; |
| 61 | + |
| 62 | + /// The type of the callback that is used to control the execution. |
| 63 | + /// The callback is passed the current action. |
| 64 | + using CallbackTy = function_ref<Control(const ActionActiveStack *)>; |
| 65 | + |
| 66 | + /// Create an ExecutionContext with a callback that is used to control the |
| 67 | + /// execution. |
| 68 | + ExecutionContext(CallbackTy callback) { setCallback(callback); } |
| 69 | + ExecutionContext() = default; |
| 70 | + |
| 71 | + /// Set the callback that is used to control the execution. |
| 72 | + void setCallback(CallbackTy callback); |
| 73 | + |
| 74 | + /// This abstract class defines the interface used to observe an Action |
| 75 | + /// execution. It allows to be notified before and after the callback is |
| 76 | + /// processed, but can't affect the execution. |
| 77 | + struct Observer { |
| 78 | + virtual ~Observer() = default; |
| 79 | + /// This method is called before the Action is executed |
| 80 | + /// If a breakpoint was hit, it is passed as an argument to the callback. |
| 81 | + /// The `willExecute` argument indicates whether the action will be executed |
| 82 | + /// or not. |
| 83 | + /// Note that this method will be called from multiple threads concurrently |
| 84 | + /// when MLIR multi-threading is enabled. |
| 85 | + virtual void beforeExecute(const ActionActiveStack *action, |
| 86 | + Breakpoint *breakpoint, bool willExecute) {} |
| 87 | + |
| 88 | + /// This method is called after the Action is executed, if it was executed. |
| 89 | + /// It is not called if the action is skipped. |
| 90 | + /// Note that this method will be called from multiple threads concurrently |
| 91 | + /// when MLIR multi-threading is enabled. |
| 92 | + virtual void afterExecute(const ActionActiveStack *action) {} |
| 93 | + }; |
| 94 | + |
| 95 | + /// Register a new `Observer` on this context. It'll be notified before and |
| 96 | + /// after executing an action. Note that this method is not thread-safe: it |
| 97 | + /// isn't supported to add a new observer while actions may be executed. |
| 98 | + void registerObserver(Observer *observer); |
| 99 | + |
| 100 | + /// Register a new `BreakpointManager` on this context. It'll have a chance to |
| 101 | + /// match an action before it gets executed. Note that this method is not |
| 102 | + /// thread-safe: it isn't supported to add a new manager while actions may be |
| 103 | + /// executed. |
| 104 | + void addBreakpointManager(BreakpointManager *manager) { |
| 105 | + breakpoints.push_back(manager); |
| 106 | + } |
| 107 | + |
| 108 | + /// Process the given action. This is the operator called by MLIRContext on |
| 109 | + /// `executeAction()`. |
| 110 | + void operator()(function_ref<void()> transform, const Action &action); |
| 111 | + |
| 112 | +private: |
| 113 | + /// Callback that is executed when a breakpoint is hit and allows the client |
| 114 | + /// to control the execution. |
| 115 | + CallbackTy onBreakpointControlExecutionCallback; |
| 116 | + |
| 117 | + /// Next point to stop execution as describe by `Control` enum. |
| 118 | + /// This is handle by indicating at which levels of depth the next |
| 119 | + /// break should happen. |
| 120 | + Optional<int> depthToBreak; |
| 121 | + |
| 122 | + /// Observers that are notified before and after the callback is executed. |
| 123 | + SmallVector<Observer *> observers; |
| 124 | + |
| 125 | + /// The list of managers that are queried for breakpoints. |
| 126 | + SmallVector<BreakpointManager *> breakpoints; |
| 127 | +}; |
| 128 | + |
| 129 | +} // namespace tracing |
| 130 | +} // namespace mlir |
| 131 | + |
| 132 | +#endif // MLIR_TRACING_EXECUTIONCONTEXT_H |
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