Original Redmine Comment
Author Name: Jie Xu (@jiexu)
Original Date: 2015-04-24T12:03:06Z

Hi, looked into both of your debug info files. The errors happen at in V3Gate.cpp where it tries to generate SYNCASYNCNET warning.

To me the reason it happens is that the node it try to find is already deleted in a earlier stage. It would nice to share your altera_avalon_mm_clock_crossing_bridge.v or at least the part with warnings.

Also when you have the callback from the debugger, go back to the frame of GateVisitor::warnSignals() and check which signal is the problem. You can find a GDB script file verilator source src/.gdbinit where some function are defined to check the node. But I don't know if you can do something similar in LLDB.

Original Redmine Comment
Author Name: Sebastian Dressler
Original Date: 2015-04-24T12:55:45Z

Hi,

We do not get a segfault, when using the verilator_bin_dbg, there we retrieve proper warnings and are able to detect the signal causing this. However, when using plain verilator_bin it segfaults. I was able to do a detailed traceback after compiling with ```-g -O0

Cheers,
Sebastian

Original Redmine Comment
Author Name: Jie Xu (@jiexu)
Original Date: 2015-04-24T13:32:24Z

Seems to me this is a clear error which should be reproducible on every run unless there are some different optimization options when calling Verilator.

If my assumptions are correct, you can try the patch:

diff --git a/src/V3Gate.cpp b/src/V3Gate.cpp
index e933ae4..039e30d 100644
--- a/src/V3Gate.cpp
+++ b/src/V3Gate.cpp
@@ -360,6 +360,8 @@ private:
      // VISITORS
      virtual void visit(AstNetlist* nodep, AstNUser*) {
         nodep->iterateChildren(*this);
+       // Warn
+       warnSignals();
         //if (debug()>6) m_graph.dump();
         if (debug()>6) m_graph.dumpDotFilePrefixed("gate_pre");
         m_graph.removeRedundantEdgesSum(&V3GraphEdge::followAlwaysTrue);
@@ -373,8 +375,6 @@ private:
         // Remove redundant logic
         if (v3Global.opt.oDedupe()) dedupe();
         if (v3Global.opt.oAssemble()) mergeAssigns();
-       // Warn
-       warnSignals();
         consumedMark();
         m_graph.dumpDotFilePrefixed("gate_opt");
         // Rewrite assignments

Basically I move the warning part before the optimizations in V3Gate where some nodes could be optimized out.

Original Redmine Comment
Author Name: Wilson Snyder (@wsnyder)
Original Date: 2015-04-27T10:47:38Z

Thanks for patching, makes sense. Fixed in git towards 3.873.

Original Redmine Comment
Author Name: Wilson Snyder (@wsnyder)
Original Date: 2015-06-06T18:03:48Z

In 3.874.