Identifying hierarchical chip design intellectual property through digests

A computer-implemented method of analyzing cells in a hierarchical design of a circuit device for functional similarity, the method including:

• analyzing the hierarchical design using a processor to determine dependency chains from leaf cells that do not reference any other cells in the hierarchical design upward to higher levels in the hierarchical design, wherein n−level cells, by definition, are limited to referencing leaf cells through n−1 level cells and not referencing n−level or n+level cells;
• detecting matching leaf cells by comparing digests of at least portions of the leaf cells, assigning matching names to the matching leaf cells, and propagating the matching names to higher level cells in the hierarchical design in place of the original, non-matching names of the matching leaf cells;
• applying the detecting, assigning and propagating steps to at least some first-level, second-level, third-level, and subsequent-level cells along the dependency chains;
• and
• evaluating functional similarity of at least some of the n-level cells above the leaf cells in the hierarchical design after propagating the matching names into the n−level cells along the dependency chains.

A computer-readable storage medium storing computer program instructions that, when executed on a processor, carry out actions including:

• calculating digests for at least some leaf cells in the hierarchical design, using a processor, wherein the leaf cells do not contain references to other cells in the design;
• detecting matching leaf cells that have functionally identical designs using the calculated digests;
• assigning matching names to the matching leaf cells to replace original, non-matching names of the matching leaf cells;
• propagating the matching names to higher level cells in the hierarchical design in place of the original names of the matching leaf cells;
• and
• calculating digests for at least some of the higher level cells after the propagating of the matching names into the higher level cells.

A computer-readable storage medium storing computer program instructions that, when executed on a processor, carry out actions including:

• analyzing the hierarchical design using a processor to determine dependency chains from leaf cells that do not reference any other cells in the hierarchical design upward to higher levels in the hierarchical design, wherein n-level cells, by definition, are limited to referencing leaf cells through n−1 level cells and not referencing n−level or n+level cells;
• detecting matching leaf cells, assigning matching names to the matching leaf cells by comparing digests of at least portions of the leaf cells, and propagating the matching names to higher level cells in the hierarchical design in place of the original, non-matching names of the matching leaf cells;
• applying the detecting, assigning and propagating steps to at least some first-level, second-level, third-level, and subsequent-level cells along the dependency chains;
• and
• evaluating functional similarity of at least some of the n-level cells above the leaf cells in the hierarchical design after propagating the matching names into the n−level cells along the dependency chains.

A computer system including:

• a processor;
• and
• a computer-readable storage medium storing computer program instructions that, when executed on the processor, carry out actions including:
• calculating digests for at least some leaf cells in the hierarchical design, using a processor, wherein the leaf cells do not contain references to other cells in the design;
• detecting matching leaf cells that have functionally identical designs using the calculated digests;
• assigning matching names to the matching leaf cells to replace original, non-matching names of the matching leaf cells;
• propagating the matching names to higher level cells in the hierarchical design in place of the original names of the matching leaf cells;
• and
• calculating digests for at least some of the higher level cells after the propagating of the matching names into the higher level cells.

A computer system including:

• a processor;
• and
• a computer-readable storage medium storing computer program instructions that, when executed on the processor, carry out actions including:
• analyzing the hierarchical design using a processor to determine dependency chains from leaf cells that do not reference any other cells in the hierarchical design upward to higher levels in the hierarchical design, wherein n-level cells, by definition, are limited to referencing leaf cells through n−1 level cells and not referencing n−level or n+level cells;
• detecting matching leaf cells by comparing digests of at least portions of the leaf cells, assigning matching names to the matching leaf cells, and propagating the matching names to higher level cells in the hierarchical design in place of the original, non-matching names of the matching leaf cells;
• applying the detecting, assigning and propagating steps to at least some first-level, second-level, third-level, and subsequent-level cells along the dependency chains;
• and
• evaluating functional similarity of at least some of the n-level cells above the leaf cells in the hierarchical design after propagating the matching names into the n−level cells along the dependency chains.