Collecting application state in a runtime environment for reversible debugging

Patent metadata

Field	Value
Publication number	US-2020310942-A1
Application number	US-201916372204-A
Country	US
Kind code	A1
Filing date	Apr 1, 2019
Priority date	Apr 1, 2019
Publication date	Oct 1, 2020
Grant date	—

Abstract

Collecting runtime virtual machine external state for an application running in an application runtime virtual machine, for use in emulation of the application. A method includes identifying application bytecode for which runtime virtual machine external state is to be collected. The method further includes executing machine code generated from the bytecode to generate the runtime virtual machine external state. The method further includes collecting the runtime virtual machine external state. The method further includes storing the runtime virtual machine external state for use in emulating the application.

First claim

1 . A method of collecting runtime virtual machine external state, the virtual machine external state comprising data that cannot be reproduced by emulating execution of an application running in a runtime virtual machine, the runtime virtual machine being a virtual machine being configured to execute an application by compiling bytecode into native machine code, the virtual machine external state being for use in emulation of the application, the method comprising:
identifying application bytecode for which runtime virtual machine external state is to be collected; executing native machine code generated from the bytecode causing state of the runtime virtual machine to change; capture one or more snapshots of states of the runtime virtual machine; wherein executing the native machine code generated from the bytecode further causes the runtime virtual machine external state; collecting the runtime virtual machine external state; and storing the snapshots and the runtime virtual machine external state for use in emulating the application, such that emulation can be started from a snapshot and runtime virtual machine external state can be provided as needed as emulation proceeds from the snapshot.

2 . The method of claim 1 , wherein identifying application bytecode for which runtime virtual machine external state is to be collected comprises identifying runtime virtual machine boundaries in execution of the application, and as a result collecting application state between those runtime virtual machine boundaries.

3 . The method of claim 1 , wherein identifying application bytecode for which runtime virtual machine external state is to be collected comprises identifying user generated code boundaries in execution of the application, and collecting application state between those user generated code boundaries.

4 . The method of claim 1 , wherein identifying application bytecode for which runtime virtual machine external state is to be collected comprises identifying user identified code.

5 . The method of claim 1 , wherein emulation of the application is performed on portions of the application to collect immediate state able to be generated by emulating the application without creating native machine code in conjunction with executing portions of the application to collect the runtime virtual machine external state.

6 . The method of claim 5 , wherein an emulator used for emulating the application sets breakpoints in the machine code when the emulator identifies locations in the bytecode where runtime virtual machine external state is required, causing a break in executing the native machine code for collecting the runtime virtual machine external state.

7 . The method of claim 1 , wherein an emulator identifies locations in the bytecode where runtime virtual machine external state is required by identifying code that performs at least one of: obtaining a random number, obtaining a time, obtaining data from another source external to runtime virtual machine code in the runtime virtual machine, identifying shared memory reads, or identifying points where multithreading occurs.

8 . A computer system comprising:
one or more processors; and one or more computer-readable media having stored thereon instructions that are executable by the one or more processors to configure the computer system to collect runtime virtual machine external state, the virtual machine external state comprising data that cannot be reproduced by emulating execution of an application running in a runtime virtual machine, the runtime virtual machine being a virtual machine being configured to execute an application by compiling bytecode into native machine code, the virtual machine external state being for use in emulation of the application, including instructions that are executable to configure the computer system to perform at least the following:
identify application bytecode for which runtime virtual machine external state is to be collected;
execute native machine code generated from the bytecode causing state of the runtime virtual machine to change;
capture one or more snapshots of states of the runtime virtual machine;
wherein executing the native machine code generated from the bytecode further causes the runtime virtual machine external state to be generated, the runtime virtual machine external state comprising data that cannot be reproduced by emulating execution of the application;
collect the runtime virtual machine external state; and
store the snapshots and the runtime virtual machine external state for use in emulating the application.

9 . The computer system of claim 8 , wherein identifying application bytecode for which runtime virtual machine external state is to be collected comprises identifying runtime virtual machine boundaries in execution of the application, and as a result collecting application state between those runtime virtual machine boundaries.

10 . The computer system of claim 8 , wherein identifying application bytecode for which runtime virtual machine external state is to be collected comprises identifying user generated code boundaries in execution of the application, and collecting application state between those user generated code boundaries.

11 . The computer system of claim 8 , wherein identifying application bytecode for which runtime virtual machine external state is to be collected comprises identifying user identified code.

12 . The computer system of claim 8 , wherein emulation of the application is performed on portions of the application to collect immediate state able to be generated by emulating the application without creating native machine code in conjunction with executing portions of the application to collect the runtime virtual machine external state.

13 . The computer system of claim 12 , wherein an emulator used for emulating the application sets breakpoints in the machine code when the emulator identifies locations in the bytecode where runtime virtual machine external state is required, causing a break in executing the native machine code for collecting the runtime virtual machine external state.

14 . The computer system of claim 8 , wherein an emulator identifies locations in the bytecode where runtime virtual machine external state is required by identifying code that performs at least one of: obtaining a random number, obtaining a time, obtaining data from another source external to runtime virtual machine code in the runtime virtual machine, identifying shared memory reads, or identifying points where multithreading occurs.

15 . A computer-readable storage hardware device having stored thereon instructions that are executable by one or more processors to configure a computer system to collect runtime virtual machine external state, the virtual machine external state comprising data that cannot be reproduced by emulating execution of an application running in a runtime virtual machine, the runtime virtual machine being a virtual machine being configured to execute an application by compiling bytecode into native machine code, the virtual machine external state being for use in emulation of the application, the computer-readable storage device including instructions that are executable to configure the computer system to perform at least the following:
identify application bytecode for which runtime virtual machine external state is to be collected; execute native machine code generated from the bytecode causing state of the runtime virtual machine to change; capture one or more snapshots of states of the runtime virtual machine; wherein executing the native machi

Assignees

• Microsoft Technology Licensing Llc

Inventors

• Nelson Patrick Lothian
• Davis Jackson Michael
• Myers Del
• Lai Thomas

Classifications

• G06F9/45504 Primary

  Abstract machines for programme code execution, e.g. Java virtual machine [JVM], interpreters, emulators · CPC title

• G06F11/3652

  in-circuit-emulation [ICE] arrangements · CPC title

• G06F11/3612 Primary

  by runtime analysis (performance monitoring G06F11/3466) · CPC title

• G06F11/3636

  by tracing the execution of the program · CPC title

• G06F9/45558

  Hypervisor-specific management and integration aspects · CPC title