verilator/test_regress/t/t_constraint_global_nested_...

110 lines
3.6 KiB
Systemverilog

// DESCRIPTION: Verilator: Verilog Test module
//
// This file ONLY is placed under the Creative Commons Public Domain.
// SPDX-FileCopyrightText: 2026 PlanV GmbH
// SPDX-License-Identifier: CC0-1.0
// Test: rand_mode on nested object's variable should not cause Z3 solver error.
// Previously, the generated SMT constraint used "#x0" instead of the variable
// name for nested rand variables when rand_mode was involved, causing a width
// mismatch in the constraint solver.
class InnerClass;
rand bit [7:0] inner_val1;
rand bit [7:0] inner_val2;
constraint inner_con {
inner_val1 inside {[8'd10 : 8'd50]};
inner_val2 inside {[8'd100 : 8'd200]};
}
function new();
inner_val1 = 0;
inner_val2 = 0;
endfunction
endclass
class OuterClass;
rand InnerClass nested_obj;
rand bit [7:0] outer_val;
constraint outer_con {outer_val inside {[8'd1 : 8'd20]};}
function new();
nested_obj = new();
outer_val = 0;
endfunction
endclass
module t_constraint_global_nested_randmode;
OuterClass obj;
int rand_ok;
int change_count;
bit [7:0] prev_val;
initial begin
obj = new();
// Test 1: Normal randomization of nested object with constraints
rand_ok = obj.randomize();
if (rand_ok == 0) $stop;
if (obj.nested_obj.inner_val1 < 8'd10 || obj.nested_obj.inner_val1 > 8'd50) $stop;
if (obj.nested_obj.inner_val2 < 8'd100 || obj.nested_obj.inner_val2 > 8'd200) $stop;
if (obj.outer_val < 8'd1 || obj.outer_val > 8'd20) $stop;
// Test 2: Multiple randomizations with constraint checking
change_count = 0;
prev_val = obj.nested_obj.inner_val1;
repeat (10) begin
rand_ok = obj.randomize();
if (rand_ok == 0) $stop;
if (obj.nested_obj.inner_val1 < 8'd10 || obj.nested_obj.inner_val1 > 8'd50) $stop;
if (obj.nested_obj.inner_val2 < 8'd100 || obj.nested_obj.inner_val2 > 8'd200) $stop;
if (obj.outer_val < 8'd1 || obj.outer_val > 8'd20) $stop;
if (obj.nested_obj.inner_val1 != prev_val) change_count++;
prev_val = obj.nested_obj.inner_val1;
end
if (change_count == 0) $stop;
// Test 3: rand_mode(0) on nested var - must not crash solver
void'(obj.nested_obj.inner_val1.rand_mode(0));
if (obj.nested_obj.inner_val1.rand_mode() != 0) $stop;
// Calling randomize must not cause a solver crash
rand_ok = obj.randomize();
// (randomize may return 0 due to constraint interaction - separate issue)
// Test 4: Re-enable rand_mode and verify randomization resumes
void'(obj.nested_obj.inner_val1.rand_mode(1));
if (obj.nested_obj.inner_val1.rand_mode() != 1) $stop;
change_count = 0;
prev_val = obj.nested_obj.inner_val1;
repeat (10) begin
rand_ok = obj.randomize();
if (rand_ok == 0) $stop;
if (obj.nested_obj.inner_val1 != prev_val) change_count++;
prev_val = obj.nested_obj.inner_val1;
end
if (change_count == 0) $stop;
// Test 5: rand_mode(0) on entire nested object - must not crash solver
void'(obj.nested_obj.rand_mode(0));
rand_ok = obj.randomize();
// (randomize may return 0 due to constraint interaction - separate issue)
// Test 6: Re-enable nested object and verify randomization resumes
void'(obj.nested_obj.rand_mode(1));
change_count = 0;
prev_val = obj.nested_obj.inner_val1;
repeat (10) begin
rand_ok = obj.randomize();
if (rand_ok == 0) $stop;
if (obj.nested_obj.inner_val1 != prev_val) change_count++;
prev_val = obj.nested_obj.inner_val1;
end
if (change_count == 0) $stop;
$write("*-* All Finished *-*\n");
$finish;
end
endmodule