ram: add PDN strap pitch vs die size error check in ramPdngen() to prevent segfault

[tnguy19]

Summary

When the die area is smaller than the PDN strap pitch, calling RamGen::ramPdngen() can result in a segfault. This adds a check at the top of ramPdngen() to compare die dimensions against the strap pitch and give an error instead

Type of Change

• Bug fix

Impact

Instead of a segfault when PDN strap pitch is larger than the die size, user will get a clear error message indicating which dimension is too small and suggesting they use a smaller pitch

Before Fix Sample Error Message:

[INFO PDN-0001] Inserting grid: ram_grid
Signal 11 received
 2# odb::dbTrackGrid::getGridY() in openroad
 3# pdn::TechLayer::populateGrid(odb::dbBlock*, odb::dbTechLayerDir) in openroad
 4# pdn::Straps::makeShapes(...) in openroad
 8# pdn::PdnGen::buildGrids(bool) in openroad
 9# ram::RamGen::ramPdngen(...) in openroad
Segmentation fault (core dumped)

After Fix Sample Error Message:

[ERROR RAM-0031] Die height (13600 DBU) is less than horizontal strap pitch (20000 DBU). Use a smaller -hor_layer pitch.

Verification

• I have verified that the local build succeeds (./etc/Build.sh).
• I have run the relevant tests and they pass.
• My code follows the repository's formatting guidelines.
• I have signed my commits (DCO).

Related Issues

#9961

@rovinski
@gadfort

[gemini-code-assist]

Code Review

This pull request introduces validation checks in the RamGen::ramPdngen function to ensure that the die dimensions are sufficient for the specified horizontal and vertical strap pitches. Specifically, it adds error logging if the die height is less than the horizontal pitch or if the die width is less than the vertical pitch. I have no feedback to provide as there are no review comments.

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"

[gadfort]

@rovinski I think this check makes sense even if the tool is no longer segfaulting

[rovinski]

Yep, I had the same feedback via email

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"

[rovinski]

Pedantic changes

[rovinski]

Afterwards mark as ready for review

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"

[rovinski]

CI failure unrelated

[tnguy19]

Ready for review @gadfort @maliberty

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"