A view is named FUNC_SS_RCMAX, but its actual configured objects point to an FF library and a different RC condition. What does the timing engine use?
From PDVerse MMMC Interview Masterclass, part of the pdVerse Mentor Series
Direct answer
The timing engine uses the actual bound physical objects (the linked library_set and rc_corner), completely ignoring the string name of the view. A view named FUNC_SS_RCMAX that points to an FF library will evaluate fast-process physics, silently producing invalid setup results.
Mentor explanation
Timing engines evaluate bound object pointers, not human-readable string identifiers.
Key terms
- Object pointer binding —
create_analysis_viewbinds object pointers (-constraint_mode,-delay_corner), not string names. - MMMC audit script — an automated script querying
get_delay_cornersandget_library_setsto confirm that view names match physical bindings. - Silent falsification — misconfigured bindings produce reports with misleading headers that look correct but evaluate the wrong corner.
Always audit underlying object bindings with automated scripts before accepting signoff reports.
Practical example
Diagnostic Audit Script:
# In Cadence Innovus / Tempus: Auditing View Object Bindings
foreach view [all_analysis_views] {
set cm [get_analysis_view view -constraint_mode]
set dc [get_analysis_view view -delay_corner]
set lib [get_delay_corner dc -library_set]
set rc [get_delay_corner dc -rc_corner]
puts [format "VIEW: %-25s | CM: %-15s | LIB: %-15s | RC: %-15s" view cm lib rc]
}Interview trap
Trusting view names in timing reports without programmatically verifying that the underlying library set and parasitic file bindings match the intended signoff corner.
Key takeaways
- EDA timing engines execute based on underlying pointer bindings, not object name strings.
- Mismatched view names and library bindings create catastrophic silent signoff escapes.
- Always audit view configurations using programmatic queries (
get_analysis_view).
Self-check: can you answer this aloud?
Try a 45-second answer using this structure:
- State the direct answer.
- Explain the timing or physical reason.
- Name one caveat.
- Say how you would verify it in a real flow.
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