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Segmentation fault during 3_4_place_resized when sdc file contains a create_generated_clock command
Describe the bug
When a generated clock is specified in the SDC file, a segmentation fault occurs during the 3_4_place_resized stage. It appears to happen during the execution of the report_metrics command in the resize.tcl script.
It happens for both -combinational and -divide_by generated clocks: For example: create_generated_clock -name clk_gated -source clk -combinational clkgate/Q create_generated_clock -name clk_div2 -source clk -divide_by 2 \clk_div2$DFF_PN0/Q
When a generated clock is not specified for this example, the layout builds as expected.
Expected Behavior
The expected behaviour is for it to take the generated clocks into account when performing clock tree synthesis.
Environment
Unknown git commit, this is not a git repository.
Please make sure that you have the latest code changes and add the commit
hash in the description.
kernel: Linux 6.11.0-24-generic
os: Ubuntu 24.04.2 LTS (Noble Numbat)
cmake version 3.24.2
CMake Warning at CMakeLists.txt:75 (message):
OpenROAD git describe failed, using sha1 instead
-- The CXX compiler identification is GNU 13.3.0
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- OpenROAD version: d51df1dea57f1bc70b25f46fef5ce7c396d26e99
-- System name: Linux
-- Compiler: GNU 13.3.0
-- Build type: RELEASE
-- Install prefix: /usr/local
-- C++ Standard: 17
-- C++ Standard Required: ON
-- C++ Extensions: OFF
-- The C compiler identification is GNU 13.3.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Performing Test C_COMPILER_SUPPORTS__-Wall
-- Performing Test C_COMPILER_SUPPORTS__-Wall - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wall
-- Performing Test CXX_COMPILER_SUPPORTS__-Wall - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-array-bounds
-- Performing Test C_COMPILER_SUPPORTS__-Wno-array-bounds - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-array-bounds
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-array-bounds - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-nonnull
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-- Performing Test C_COMPILER_SUPPORTS__-Wno-maybe-uninitialized
-- Performing Test C_COMPILER_SUPPORTS__-Wno-maybe-uninitialized - Success
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-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-maybe-uninitialized - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-format-overflow
-- Performing Test C_COMPILER_SUPPORTS__-Wno-format-overflow - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-format-overflow
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-format-overflow - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-unused-variable
-- Performing Test C_COMPILER_SUPPORTS__-Wno-unused-variable - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-unused-variable
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-unused-variable - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-unused-function
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-- Performing Test C_COMPILER_SUPPORTS__-Wno-write-strings
-- Performing Test C_COMPILER_SUPPORTS__-Wno-write-strings - Success
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-- Performing Test C_COMPILER_SUPPORTS__-Wno-sign-compare
-- Performing Test C_COMPILER_SUPPORTS__-Wno-sign-compare - Success
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-sign-compare
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-sign-compare - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-deprecated
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-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-deprecated - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-c++11-narrowing
-- Performing Test C_COMPILER_SUPPORTS__-Wno-c++11-narrowing - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-c++11-narrowing
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-c++11-narrowing - Failed
-- Performing Test C_COMPILER_SUPPORTS__-Wno-register
-- Performing Test C_COMPILER_SUPPORTS__-Wno-register - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-register
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-register - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-format
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-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-format
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-format - Success
-- Performing Test C_COMPILER_SUPPORTS__-Wno-reserved-user-defined-literal
-- Performing Test C_COMPILER_SUPPORTS__-Wno-reserved-user-defined-literal - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-reserved-user-defined-literal
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-reserved-user-defined-literal - Failed
-- Performing Test C_COMPILER_SUPPORTS__-fpermissive
-- Performing Test C_COMPILER_SUPPORTS__-fpermissive - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__-fpermissive
-- Performing Test CXX_COMPILER_SUPPORTS__-fpermissive - Success
-- Performing Test C_COMPILER_SUPPORTS__-x
-- Performing Test C_COMPILER_SUPPORTS__-x - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__-x
-- Performing Test CXX_COMPILER_SUPPORTS__-x - Failed
-- Performing Test C_COMPILER_SUPPORTS__c++
-- Performing Test C_COMPILER_SUPPORTS__c++ - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__c++
-- Performing Test CXX_COMPILER_SUPPORTS__c++ - Failed
-- Performing Test C_COMPILER_SUPPORTS__-std=c++17
-- Performing Test C_COMPILER_SUPPORTS__-std=c++17 - Failed
-- Performing Test CXX_COMPILER_SUPPORTS__-std=c++17
-- Performing Test CXX_COMPILER_SUPPORTS__-std=c++17 - Success
-- Performing Test C_COMPILER_SUPPORTS__-fno-exceptions
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-- Performing Test CXX_COMPILER_SUPPORTS__-fno-exceptions
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-- Performing Test C_COMPILER_SUPPORTS__-Wno-unused-but-set-variable
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-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-unused-but-set-variable
-- Performing Test CXX_COMPILER_SUPPORTS__-Wno-unused-but-set-variable - Success
-- Found Python3: /usr/bin/python3.12 (found version "3.12.3") found components: Interpreter
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Success
-- Found Threads: TRUE
-- TCL library: /usr/lib/x86_64-linux-gnu/libtcl.so
-- TCL header: /usr/include/tcl/tcl.h
-- TCL readline library: /usr/lib/x86_64-linux-gnu/libtclreadline.so
-- TCL readline header: /usr/include/x86_64-linux-gnu
-- Found SWIG: /usr/local/bin/swig (found suitable version "4.1.0", minimum required is "4.0")
-- Using SWIG >= 4.1.0 -flatstaticmethod flag for python
-- Found Boost: /usr/local/lib/cmake/Boost-1.86.0/BoostConfig.cmake (found version "1.86.0") found components: iostreams
-- boost: 1.86.0
-- Found GTest: /usr/local/lib/cmake/GTest/GTestConfig.cmake (found version "1.13.0")
-- GTest: 1.13.0
-- Found Python3: /usr/include/python3.12 (found version "3.12.3") found components: Development Development.Module Development.Embed
-- Found ZLIB: /usr/local/lib/libz.a (found version "1.3.1")
-- spdlog: 1.15.0
-- Found BISON: /usr/local/bin/bison (found version "3.8.2")
-- Could NOT find Doxygen (missing: DOXYGEN_EXECUTABLE)
-- STA version: 2.6.2
-- STA git sha: 65c2943191b8c59a065fcbb28519917a944eadef
-- System name: Linux
-- Compiler: GNU 13.3.0
-- Build type: RELEASE
-- Build CXX_FLAGS: -O3 -DNDEBUG
-- Install prefix: /usr/local
-- Found FLEX: /usr/bin/flex (found version "2.6.4")
-- TCL library: /usr/lib/x86_64-linux-gnu/libtcl.so
-- TCL header: /usr/include/tcl/tcl.h
-- TCL readline library: /usr/lib/x86_64-linux-gnu/libtclreadline.so
-- TCL readline header: /usr/include/x86_64-linux-gnu/tclreadline.h
-- CUDD library: /usr/local/lib/libcudd.a
-- CUDD header: /usr/local/include/cudd.h
-- SSTA: 0
-- Found SWIG: /usr/local/bin/swig (found suitable version "4.1.0", minimum required is "3.0")
-- STA executable: /radstd/tools/openroad/build-2025-06-03/OpenROAD-flow-scripts/tools/OpenROAD/src/sta/app/sta
-- Found re2: /usr/local/lib/cmake/re2/re2Config.cmake (found version "11.0.0")
-- Found Clp: /usr/local/lib/cmake/Clp/ClpConfig.cmake (found version "1.17.7")
-- Found Cbc: /usr/local/lib/cmake/Cbc/CbcConfig.cmake (found version "2.10.7")
-- Found SCIP: /usr/local/lib/cmake/scip/scip-config.cmake (found version "9.0.0")
-- Found OpenMP_CXX: -fopenmp (found version "4.5")
-- Found OpenMP: TRUE (found version "4.5")
-- Found OR-Tools: /usr/local/lib/cmake/ortools (version: 9.11.4210)
-- TCL library: /usr/lib/x86_64-linux-gnu/libtcl.so
-- TCL header: /usr/include/tcl/tcl.h
-- Found Boost: /usr/local/lib/cmake/Boost-1.86.0/BoostConfig.cmake (found version "1.86.0")
-- Found OpenMP_C: -fopenmp (found version "4.5")
-- Found OpenMP: TRUE (found version "4.5")
-- Found OpenMP: TRUE (found version "4.5")
-- GUI is enabled
-- Found Boost: /usr/local/lib/cmake/Boost-1.86.0/BoostConfig.cmake (found version "1.86.0") found components: serialization
-- Could NOT find VTune (missing: VTune_LIBRARIES VTune_INCLUDE_DIRS)
-- Found Boost: /usr/local/lib/cmake/Boost-1.86.0/BoostConfig.cmake (found suitable version "1.86.0", minimum required is "1.78")
-- TCL library: /usr/lib/x86_64-linux-gnu/libtcl.so
-- TCL header: /usr/include/tcl/tcl.h
-- Found Boost: /usr/local/lib/cmake/Boost-1.86.0/BoostConfig.cmake (found version "1.86.0") found components: serialization system thread
-- Found Boost: /usr/local/lib/cmake/Boost-1.86.0/BoostConfig.cmake (found version "1.86.0")
-- Found Eigen3: /usr/local/share/eigen3/cmake/Eigen3Config.cmake (found version "3.4.0")
-- TCL readline enabled
-- Tcl Extended disabled
-- Python3 enabled
-- Configuring done
-- Generating done
-- Build files have been written to: /tmp/tmp.S8d8TVk3m9
To Reproduce
- Untar the uploaded file resize_create_generated_clock.tar.gz tarball and go to the directory
- Run ./run-me-clk_tree_testcase-gf180-base.sh
Relevant log output
OpenROAD v2.0-21872-gd51df1dea5
Features included (+) or not (-): +GPU +GUI +Python
This program is licensed under the BSD-3 license. See the LICENSE file for details.
Components of this program may be licensed under more restrictive licenses which must be honored.
[INFO ORD-0030] Using 8 thread(s).
Perform port buffering...
[INFO RSZ-0027] Inserted 2 input buffers.
[INFO RSZ-0028] Inserted 9 output buffers.
Perform buffer insertion and gate resizing...
repair_design -verbose
[INFO RSZ-0058] Using max wire length 119881um.
Iteration | Area | Resized | Buffers | Nets repaired | Remaining
---------------------------------------------------------------------
0 | +0.0% | 0 | 0 | 0 | 41
10 | +0.0% | 0 | 0 | 0 | 31
20 | -3.9% | 4 | 0 | 0 | 21
30 | -7.8% | 13 | 0 | 0 | 11
40 | -9.9% | 18 | 0 | 0 | 1
final | -9.9% | 18 | 0 | 0 | 0
---------------------------------------------------------------------
[INFO RSZ-0039] Resized 18 instances.
Repair tie lo fanout...
[INFO RSZ-0042] Inserted 1 tie gf180mcu_fd_sc_mcu9t5v0__tiel instances.
Repair tie hi fanout...
Floating nets:
Report metrics stage 3, resizer...
Signal 11 received
Stack trace:
0# 0x000055A6BAD02863 in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
1# 0x000074A916E45330 in /lib/x86_64-linux-gnu/libc.so.6
2# sta::Path::setPrevPath(sta::Path*) in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
3# sta::Genclks::updateSrcPathPrevs() in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
4# sta::Search::findFilteredArrivals(bool) in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
5# sta::Search::findPathEnds(sta::ExceptionFrom*, sta::Vector<sta::ExceptionThru*>*, sta::ExceptionTo*, bool, sta::Corner const*, sta::MinMaxAll const*, unsigned long, unsigned long, bool, float, float, bool, sta::Set<char const*, sta::CharPtrLess>*, bool, bool, bool, bool, bool, bool) in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
6# sta::Sta::findPathEnds(sta::ExceptionFrom*, sta::Vector<sta::ExceptionThru*>*, sta::ExceptionTo*, bool, sta::Corner const*, sta::MinMaxAll const*, int, int, bool, float, float, bool, sta::Set<char const*, sta::CharPtrLess>*, bool, bool, bool, bool, bool, bool) in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
7# 0x000055A6BAF5800C in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
8# TclNRRunCallbacks in /lib/x86_64-linux-gnu/libtcl8.6.so
9# 0x000074A91BEB86BC in /lib/x86_64-linux-gnu/libtcl8.6.so
10# Tcl_EvalEx in /lib/x86_64-linux-gnu/libtcl8.6.so
11# Tcl_Eval in /lib/x86_64-linux-gnu/libtcl8.6.so
12# sta::sourceTclFile(char const*, bool, bool, Tcl_Interp*) in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
13# 0x000055A6BAD01FCF in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
14# Tcl_MainEx in /lib/x86_64-linux-gnu/libtcl8.6.so
15# main in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
16# 0x000074A916E2A1CA in /lib/x86_64-linux-gnu/libc.so.6
17# __libc_start_main in /lib/x86_64-linux-gnu/libc.so.6
18# _start in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
Segmentation fault (core dumped)
Command exited with non-zero status 139
Elapsed time: 0:02.33[h:]min:sec. CPU time: user 0.96 sys 0.14 (47%). Peak memory: 135644KB.
Screenshots
No response
Additional Context
resize_create_generated_clock.tar.gz
@precisionmoon its not clear if this is a CTS issue or an sta one. Please triage (or work with @arthurjolo )
This is an STA issue. We haven't even got to CTS step (4_1) yet.
But the SDC seems a little strange:
create_generated_clock -name clk_gated -source clk -combinational clkgate/Q
Usually, clock gater outputs don't become generated clocks. Whatever clock feeds the clock gater input simply passes through gater output. Perhaps removing this gen clock alone may resolve the fatal.
My bad on the step. Can this be turned into an sta test case to file upstream?
precisionmoon wrote:
This is an STA issue. We haven't even got to CTS step (4_1) yet.
But the SDC seems a little strange:
create_generated_clock -name clk_gated -source clk -combinational clkgate/Q
Usually, clock gater outputs don't become generated clocks. Whatever clock feeds the clock gater input simply passes through gater output. Perhaps removing this gen clock alone may resolve the fatal.
I also tried the following non-combinational constraint in the SDC file and still got a seg fault:
create_generated_clock -name clk_div2 -source clk -divide_by 2 \clk_div2\$_DFF_PN0_/Q
This is definitely necessary to include the divided clock in the static timing analysis.
It is in the SDC file in the uploaded testcase, but commented out.
maliberty wrote:
Can this be turned into an sta test case to file upstream?
I'm not sure what you mean by this. Was it directed at me or the code maintainers?
I did a bit more digging and agree that it is an STA issue.
The exact STA line in report_metrics.tcl that triggers the seg fault appears to be:
set inp_to_reg_critical_path [lindex [find_timing_paths -path_delay min -from [all_inputs] -to [all_registers]] 0]
What is strange is that is has already successfully run the same line for max path_delay.
I have created the following OpenSTA issue with a test case: https://github.com/parallaxsw/OpenSTA/issues/257
Great. Once that is fixed we can update the sta version in OR and close this.
Hi guys,
jjcherry56 has closed OpenSTA issue #257. However, when I tried patching his two commits (72e1c10 and 6a28a3d) to the latest OpenRoad git repo, I got another segmentation fault, this time during clock tree synthesis.
Log output:
[INFO CTS-0124] Clock net "clk"
[INFO CTS-0125] Sinks 1
[INFO CTS-0124] Clock net "clk_regs"
[INFO CTS-0125] Sinks 1
[INFO CTS-0098] Clock net "clk_gated"
[INFO CTS-0099] Sinks 8
[INFO CTS-0100] Leaf buffers 0
[INFO CTS-0101] Average sink wire length 60.54 um
[INFO CTS-0102] Path depth 2 - 2
[INFO CTS-0207] Leaf load cells 0
[WARNING CTS-0002] No paths found for pin counter\[3\]$_DFF_PN0_/CLK.
[WARNING CTS-0002] No paths found for pin counter\[4\]$_DFF_PN0_/CLK.
[WARNING CTS-0002] No paths found for pin counter\[6\]$_DFF_PN0_/CLK.
[WARNING CTS-0002] No paths found for pin counter\[7\]$_DFF_PN0_/CLK.
[WARNING CTS-0002] No paths found for pin counter\[0\]$_DFF_PN0_/CLK.
[WARNING CTS-0002] No paths found for pin counter\[1\]$_DFF_PN0_/CLK.
[WARNING CTS-0002] No paths found for pin counter\[2\]$_DFF_PN0_/CLK.
[WARNING CTS-0002] No paths found for pin counter\[5\]$_DFF_PN0_/CLK.
Signal 11 received
Stack trace:
0# 0x00005A103D43D0E3 in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
1# 0x000071BF03C45330 in /lib/x86_64-linux-gnu/libc.so.6
2# sta::Path::setPrevPath(sta::Path*) in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
3# sta::Genclks::updateSrcPathPrevs() in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
4# sta::Search::findArrivals1(int) in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
5# 0x00005A103D80AD16 in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
6# cts::TritonCTS::balanceMacroRegisterLatencies() in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
7# cts::TritonCTS::runTritonCts() in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
8# 0x00005A103DC155E3 in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
9# TclNRRunCallbacks in /lib/x86_64-linux-gnu/libtcl8.6.so
10# 0x000071BF08DB66BC in /lib/x86_64-linux-gnu/libtcl8.6.so
11# Tcl_EvalEx in /lib/x86_64-linux-gnu/libtcl8.6.so
12# Tcl_Eval in /lib/x86_64-linux-gnu/libtcl8.6.so
13# sta::sourceTclFile(char const*, bool, bool, Tcl_Interp*) in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
14# 0x00005A103D43C84F in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
15# Tcl_MainEx in /lib/x86_64-linux-gnu/libtcl8.6.so
16# main in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
17# 0x000071BF03C2A1CA in /lib/x86_64-linux-gnu/libc.so.6
18# __libc_start_main in /lib/x86_64-linux-gnu/libc.so.6
19# _start in /radstd/tools/openroad/build/ubuntu24.04/OpenROAD/bin/openroad
Segmentation fault (core dumped)
Command exited with non-zero status 139
Elapsed time: 0:04.85[h:]min:sec. CPU time: user 3.63 sys 0.08 (76%). Peak memory: 155196KB.
Is it possible that the fix that was done to OpenSTA has uncovered another bug in the OpenRoad CTS stage?
cts_clk_tree_testcase_gf180_base_2025-06-24_23-31.tar.gz
The stack is still inside sta. I'm just going to update the sta submodule rather than mess with patch files. If that doesn't resolve it the problem will have to go back to sta for further fixes.