Soft blockage support for detailed placement.#9080
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sakundu wants to merge 2 commits intoThe-OpenROAD-Project:masterfrom
Open
Soft blockage support for detailed placement.#9080sakundu wants to merge 2 commits intoThe-OpenROAD-Project:masterfrom
sakundu wants to merge 2 commits intoThe-OpenROAD-Project:masterfrom
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Signed-off-by: Sayak Kundu <sakundu@ucsd.edu>
Signed-off-by: Sayak Kundu <sakundu@ucsd.edu>
osamahammad21
requested changes
Jan 4, 2026
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| // Fallback: detect buffers/inverters/tie cells by master name pattern when STA not available | ||
| // Common naming conventions: BUF_*, INV_*, CLKBUF_*, CLKINV_*, TIE*, etc. | ||
| std::string master_name = master->getName(); | ||
| // Convert to uppercase for case-insensitive matching | ||
| std::transform( | ||
| master_name.begin(), master_name.end(), master_name.begin(), ::toupper); | ||
| if (master_name.find("BUF") != std::string::npos | ||
| || master_name.find("INV") != std::string::npos | ||
| || master_name.find("TIE") != std::string::npos) { | ||
| return true; | ||
| } |
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This fallback feels quite hacky. Is there a reason for STA not being available?
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| if (cell == nullptr) { | ||
| return true; // No cell = no violation | ||
| } |
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should be an error, but to be consistent with the rest of PlacementDRC, just remove.
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| std::string master_name = master->getName(); | ||
| // Convert to uppercase for case-insensitive matching | ||
| std::transform( | ||
| master_name.begin(), master_name.end(), master_name.begin(), ::toupper); |
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warning: no header providing "toupper" is directly included [misc-include-cleaner]
src/dpl/src/PlacementDRC.cpp:3:
- #include <cstddef>
+ #include <cctype>
+ #include <cstddef>| std::string master_name = master->getName(); | ||
| // Convert to uppercase for case-insensitive matching | ||
| std::transform( | ||
| master_name.begin(), master_name.end(), master_name.begin(), ::toupper); |
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warning: use a ranges version of this algorithm [modernize-use-ranges]
Suggested change
| master_name.begin(), master_name.end(), master_name.begin(), ::toupper); | |
| std::ranges::transform( | |
| master_name,, master_name.begin(), ::toupper); |
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Hi OpenROAD team,
We have implemented soft blockage support in the detailed placement (DPL) module for our ISPD26 gate sizing and buffering contest. Soft blockages define regions where only specific cell types are permitted, such as buffers, inverters, tie cells, and physical cells, while regular logic cells are disallowed. We would appreciate it if you could review our code. Since soft blockage support is required for our contest, it would be great if this functionality could be made available in OpenROAD.
Thanks,
Sayak
Below is a brief description of the PR:
Motivation
For the ISPD'26 gate sizing and buffering contest, we use soft blockages to define regions where only buffers, inverters, tie cells, physical cells) should be placed, while preventing combinational and sequential logic cells from being placed in those regions.
Problem
Current DPL completely ignores soft blockages:
This implies that soft blockage constraints were not enforced during
detailed_placementorcheck_placement. To ensure that contest participants receive legal detailed placement solutions and that their results are evaluated correctly, DPL must properly honor soft blockages.Solution
This PR adds soft blockage support to DPL by:
is_soft_blockedcheckSoftBlockage()to validate cell placement against soft blockage rulesChanges
is_soft_blockedflag to Pixel structure and modifiedmarkBlocked()to handle soft blockages separately from hard blockagescheckSoftBlockage()andisAllowedInSoftBlockage()methods to validate cell placement against soft blockage rulesFiles Modified
src/dpl/CMakeLists.txt- Added dbSta_lib dependencysrc/dpl/include/dpl/Opendp.h- Added STA pointer for buffer/inverter detectionsrc/dpl/src/CheckPlacement.cpp- Added soft blockage violation trackingsrc/dpl/src/Opendp.cpp- Updated saveFailures call signaturesrc/dpl/src/PlacementDRC.cpp- Implemented soft blockage checking logicsrc/dpl/src/PlacementDRC.h- Added soft blockage method declarationssrc/dpl/src/dbToOpendp.cpp- Pass STA to PlacementDRCsrc/dpl/src/infrastructure/Grid.cpp- Mark soft blocked pixelssrc/dpl/src/infrastructure/Grid.h- Added is_soft_blocked to Pixelsrc/odb/src/swig/tcl/dbtypes.i- Added uint8_t typemapTest