Segmentation fault caused by null pointer ranges_ inside PGModule::dump

[YikeZhou]

Hi,

I tried to run ivl with the -P <path> flag. However, I got a segmentation fault when working with examples/sqrt.vl.

Here is the backtrace:

#0  PGate::dump_ranges (this=this@entry=0x555555898490, out=...) at pform_dump.cc:721
#1  0x000055555573910d in PGModule::dump (this=0x555555898490, out=..., ind=<optimized out>) at pform_dump.cc:826
#2  0x000055555573ff63 in Module::dump (this=<optimized out>, out=...) at pform_dump.cc:1783
#3  0x00005555557401de in pform_dump (out=..., mod=<optimized out>) at pform_dump.cc:1815
#4  0x0000555555605cdc in main (argc=<optimized out>, argv=<optimized out>) at main.cc:1168

After investigation, I found that this segmentation fault happened when dumping a PGModule object in module main. Therefore, I guess this PGModule object corresponds to the following line in the module definition:

iverilog/examples/sqrt.vl

Line 123 in 06077ed

sqrt32 root(.clk(clk), .rdy(rdy), .reset(reset), .x(value), .y(result));

Additionally, PGModule::dump doesn't check whether ranges_ is null before calling the dump_ranges() function, resulting in this segmentation fault.
After wrapping dump_ranges(out); with if (is_array()) {...}, the segmentation fault was eliminated.

iverilog/pform_dump.cc

Line 721 in 06077ed

for (list<pform_range_t>::iterator cur = ranges_->begin()

iverilog/pform_dump.cc

Line 826 in 06077ed

dump_ranges(out);