Mapping a stack in a stack machine environment

A method for mapping a Java bytecode stack up to a destination program counter, said Java bytecode stack having a layout of instructions for a method including one or more branches, said method comprising:

• mapping a path of control flow on the stack from any start point in a selected method to the destination program counter by locating a linear path from the beginning of the method to the destination program counter and iteratively processing an existing bytecode sequence at each branch, and identifying said path as complete when said destination counter is reached, said mapping including processing a first linear bytecode sequence until the control flow is interrupted;
• simulating stack actions for executing said existing bytecodes along said path, and constructing a virtual stack for storage in a pre-allocated memory location;
• and
• recording unprocessed targets from any branches in the first linear bytecode sequence for future processing.

A computer-readable media having computer readable program code embodied therein for executing a method for mapping a valid stack up to a destination program counter, said stack having a layout of instructions for a method including one or more branches, the computer readable program code configured for executing method steps comprising:

• mapping a path of control flow on the stack from any start point in a selected method to the destination program counter by locating a linear path from the beginning of the method to the destination program counter and iteratively processing an existing bytecode sequence for each branch, and identifying said path as complete when said destination program counter is reached, said mapping including processing a first linear bytecode sequence until the control flow is interrupted;
• simulating stack actions for executing said existing bytecodes along said path, and constructing a virtual stack for storage in a pre-allocated memory location;
• and
• recording unprocessed targets from any branches in the first linear bytecode sequence for future processing.

A computer readable media having computer readable program code embodied therein for executing a method for mapping a Java bytecode stack up to a destination program counter, said Java bytecode stack having a layout of instructions for a method including one or more branches, the computer readable program code configured for executing method steps comprising:

• mapping a path of control flow on the stack from any start point in a selected method to the destination program counter by locating a linear path from the beginning of the method to the destination program counter and iteratively processing an existing bytecode sequence at each branch, and identifying said path as complete when said destination counter is reached, said mapping including processing a first linear bytecode sequence until the control flow is interrupted;
• simulating stack actions for executing said existing bytecodes along said path, and constructing a virtual stack for storage in a pre-allocated memory location;
• and
• recording unprocessed targets from any branches in the first linear bytecode sequence for future processing.

A program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform method steps for mapping a valid stack up to a destination program-counter, said stack having a layout of instructions for a method including one or more branches, said method steps comprising:

• mapping a path of control flow on the stack from any start point in a selected method to the destination program counter and identifying said path as complete when said destination counter is reached;
• and
• simulating stack actions for executing existing bytecodes along said path, wherein the step of mapping a path of control flow on the stack comprises:
• processing a first linear existing bytecode sequence until the control flow is interrupted;
• and
• recording unprocessed targets in a pre-allocated memory location from any branches in the first linear existing bytecode sequence for future processing;
• and
• where the destination program counter was not reached during an earlier processing of a linear existing bytecode sequence;
• processing an additional existing bytecode linear sequence until the control flow is interrupted;
• and
• recording unprocessed targets in said pre-allocated memory location from any branches in the additional linear existing bytecode sequence for future processing.