Hierarchy-aware integrated circuit layout design

1. A computer-implemented method comprising:

identifying, by one or more processors, a current cell depicted in a view of an integrated circuit layout tool, wherein:

the current cell is of a hierarchical layout; and

the hierarchical layout comprises a plurality of cells;

generating, by one or more processors, an overlay, the overlay comprising an abstraction of at least one object present in a higher level of the hierarchical layout that overlaps with, and is within a boundary of, the current cell; and

projecting, by one or more processors, the overlay onto the current cell in the view.

2. The computer-implemented method of claim 1 , wherein generating the overlay comprises:

building, by one or more processors, a hierarchy tree from a parent cell to the current cell;

identifying, by one or more processors, an instance of the current cell that overlaps the parent cell;

creating, by one or more processors, the overlay, the overlay comprising a cover cell, wherein the cover cell is empty; and

for at least one element in the hierarchy tree from the parent cell to the current cell:

identifying, by one or more processors, presence of a metal shape in the element crossing the instance; and

appending, by one or more processors, the metal shape into the cover cell as a blockage shape.

3. The computer-implemented method of claim 2 , wherein the parent cell is selected from the group consisting of: a top cell of the hierarchical layout and a received selection of a cell at an intermediate level of the hierarchical layout.

4. The computer-implemented method of claim 2 , wherein the cover cell is of a size equal to the current cell.

5. The computer-implemented method of claim 2 , wherein identifying the instance of the current cell that overlaps the parent cell comprises identifying, by one or more processors, a plurality of instances of the current cell that overlap the parent cell, further comprising:

for each of the plurality of instances:

for at least one element in the hierarchy tree from the parent cell to the current cell:

identifying, by one or more processors, presence of a metal shape in the element crossing the respective instance; and

appending, by one or more processors, the metal shape into the cover cell as a blockage shape.

6. The computer-implemented method of claim 2 , further comprising:

attaching, by one or more processors, a net name of the metal shape to the blockage shape; and

storing, by one or more processors, information about the element corresponding to the metal shape to the blockage shape, the information selected from the group consisting of: cell name and source library.

7. The computer-implemented method of claim 1 , wherein the overlay includes a blockage shape, further comprising:

receiving, by one or more processors, a selection of the blockage shape; and

responsive to receiving the selection of the blockage shape, performing, by one or more processors, an action selected from the group consisting of: displaying information about an object corresponding to the blockage shape and displaying a window comprising a respective level of the hierarchical layout of the object corresponding to the blockage shape.

8. The computer-implemented method of claim 1 , wherein the object only present in one or more higher level views of the hierarchical layout than the view.

9. A computer program product comprising:

one or more computer readable storage media; and

program instructions stored on the one or more computer readable storage media to perform operations comprising:

identifying a current cell depicted in a view of an integrated circuit layout tool, wherein:

the current cell is of a hierarchical layout; and

the hierarchical layout comprises a plurality of cells;

generating an overlay, the overlay comprising an abstraction of at least one object present in a higher level of the hierarchical layout that overlaps with, and is within a boundary of, the current cell; and

projecting the overlay onto the current cell in the view.

10. The computer program product of claim 9 , wherein the generating the overlay comprises:

building a hierarchy tree from a parent cell to the current cell;

identifying an instance of the current cell that overlaps the parent cell;

creating the overlay, the overlay comprising a cover cell, wherein the cover cell is empty; and

for at least one element in the hierarchy tree from the parent cell to the current cell:

identifying presence of a metal shape in the element crossing the instance; and

appending the metal shape into the cover cell as a blockage shape.

11. The computer program product of claim 10 , wherein the parent cell is selected from the group consisting of: a top cell of the hierarchical layout and a received selection of a cell at an intermediate level of the hierarchical layout.

12. The computer program product of claim 10 , wherein the cover cell is of a size equal to the current cell.

13. The computer program product of claim 10 , wherein:

the identifying the instance of the current cell that overlaps the parent cell comprises identifying a plurality of instances of the current cell that overlap the parent cell; and

the operations further comprise:

for each of the plurality of instances:

for at least one element in the hierarchy tree from the parent cell to the current cell:

identifying presence of a metal shape in the element crossing the respective instance; and

appending the metal shape into the cover cell as a blockage shape.

14. The computer program product of claim 10 , wherein the operations further comprise:

attaching a net name of the metal shape to the blockage shape; and

storing information about the element corresponding to the metal shape to the blockage shape, the information selected from the group consisting of: cell name and source library.

15. The computer program product of claim 9 , wherein;

the overlay includes a blockage shape; and

the operations further comprise:

receiving a selection of the blockage shape; and

responsive to receiving the selection of the blockage shape, performing an action selected from the group consisting of: displaying information about an object corresponding to the blockage shape and displaying a window comprising a respective level of the hierarchical layout of the object corresponding to the blockage shape.

16. A computer system comprising:

a processor set;

one or more computer readable storage media; and

program instructions stored on the one or more computer readable storage media to cause the processor set to perform operations comprising:

identifying a current cell depicted in a view of an integrated circuit layout tool, wherein:

the current cell is of a hierarchical layout; and

the hierarchical layout comprises a plurality of cells;

generating an overlay, the overlay comprising an abstraction of at least one object present in a higher level of the hierarchical layout that overlaps with, and is within a boundary of, the current cell; and

projecting the overlay onto the current cell in the view.

17. The computer system of claim 16 , wherein the generating the overlay comprises:

building a hierarchy tree from a parent cell to the current cell;

identifying an instance of the current cell that overlaps the parent cell;

creating the overlay, the overlay comprising a cover cell, wherein the cover cell is empty; and

for at least one element in the hierarchy tree from the parent cell to the current cell:

identifying presence of a metal shape in the element crossing the instance; and

appending the metal shape into the cover cell as a blockage shape.

18. The computer system of claim 17 , wherein the parent cell is selected from the group consisting of: a top cell of the hierarchical layout and a received selection of a cell at an intermediate level of the hierarchical layout.

19. The computer system of claim 17 , wherein:

the identifying the instance of the current cell that overlaps the parent cell comprises identifying a plurality of instances of the current cell that overlap the parent cell; and

the operations further comprise:

for each of the plurality of instances:

for at least one element in the hierarchy tree from the parent cell to the current cell:

identifying presence of a metal shape in the element crossing the respective instance; and

appending the metal shape into the cover cell as a blockage shape.

20. The computer system of claim 16 , wherein:

the overlay includes a blockage shape; and

the operations further comprise:

receiving a selection of the blockage shape; and

responsive to receiving the selection of the blockage shape, performing an action selected from the group consisting of: displaying information about an object corresponding to the blockage shape and displaying a window comprising a respective level of the hierarchical layout of the object corresponding to the blockage shape.