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Resize size-constrained array after solver for global-constraint owners and consolidate subobj tests

This commit is contained in:
Yilou Wang 2026-06-25 14:07:12 +02:00
parent 79fcd07194
commit 8bf2f62e80
8 changed files with 193 additions and 258 deletions
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24
src/V3Randomize.cpp
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@ -4893,13 +4893,9 @@ class RandomizeVisitor final : public VNVisitor {
// basic-randomizes FIRST and lets the solver override the constrained
// leaves afterwards. This way a leaf that is only globally constrained
// (not user3) is still basic-randomized when its type is randomized
// standalone, while the owner's solver result wins.
// KNOWN LIMITATION: if such an owner also declares its own
// size-constrained array, the size-phase solver call is emitted above
// (during the genp block) before these assignments, so basicFirst cannot
// reorder it and the array size constraint is left unsolved. This
// combination cannot be built on master (the #7833 regression blocks it),
// so it is a capability gap, not a regression of working behavior.
// standalone, while the owner's solver result wins. The size-only resize
// fallback below is emitted after the solver call for such owners so an
// owner that also size-constrains its own array still resizes correctly.
AstVarRef* const fvarRefp = new AstVarRef{fl, fvarp, VAccess::WRITE};
randomizep->addStmtsp(new AstAssign{
fl, fvarRefp, basicFirst ? new AstFuncRef{fl, basicRandomizep} : beginValp});
@ -4907,13 +4903,21 @@ class RandomizeVisitor final : public VNVisitor {
const auto sizeArraysIt = m_sizeConstrainedArrays.find(nodep);
const bool needsSizePhase
= sizeArraysIt != m_sizeConstrainedArrays.end() && !sizeArraysIt->second.empty();
if (!needsSizePhase) {
// Resize fallback for an array whose size is only solver-determined (size
// constraint but no element constraint, so no two-pass size phase). It must
// run AFTER the solver .next() that computes the size variable, otherwise it
// resizes with a stale value. A basicFirst owner runs the solver LAST (after
// basic randomization), so emit the resize after the second assignment;
// otherwise the solver runs first and the resize belongs right after it.
const auto emitResizeFallback = [&]() {
if (needsSizePhase) return;
if (AstTask* const resizeAllTaskp
= VN_AS(m_memberMap.findMember(nodep, "__Vresize_constrained_arrays"), Task)) {
AstTaskRef* const resizeTaskRefp = new AstTaskRef{fl, resizeAllTaskp};
randomizep->addStmtsp(resizeTaskRefp->makeStmt());
}
}
};
if (!basicFirst) emitResizeFallback();
AstVarRef* const fvarRefReadp = fvarRefp->cloneTree(false);
fvarRefReadp->access(VAccess::READ);
@ -4923,6 +4927,8 @@ class RandomizeVisitor final : public VNVisitor {
randomizep->addStmtsp(new AstAssign{fl, fvarRefp->cloneTree(false),
new AstAnd{fl, fvarRefReadp, secondHalfp}});
if (basicFirst) emitResizeFallback();
// Call nested post_randomize on rand class-type members (IEEE 18.4.1)
if (classHasRandClassMembers(nodep)) {
AstTask* const postTaskp = getCreateNestedCallbackTask(nodep, "post");

0
test_regress/t/t_constraint_global_subobj_combined.py → test_regress/t/t_constraint_global_subobj.py
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178
test_regress/t/t_constraint_global_subobj.v Normal file
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@ -0,0 +1,178 @@
// 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
// Scenario 1 (issue #7833 literal): owner SA1 declares a global constraint on a
// sub-object's type but is NEVER randomized; a standalone randomize() of the
// holder must still randomize the nested fields.
class C1;
rand int x;
rand int y;
endclass
class B1;
rand C1 c;
function new();
c = new();
endfunction
endclass
class SA1;
rand B1 b;
constraint c_foo {b.c.x == 123;}
endclass
// Scenario 2 (combined): the SAME design randomizes both the constraint owner
// and a standalone holder of the constrained type.
class C2;
rand int x;
rand int y;
endclass
class B2;
rand C2 c;
function new();
c = new();
endfunction
endclass
class SA2;
rand B2 b;
constraint c_foo {b.c.x == 123;}
function new();
b = new();
endfunction
endclass
// Scenario 3 (multiple same-type sub-objects): two sub-objects of one type are
// each pinned by a global constraint while that type is also randomized
// standalone; the two share one underlying rand variable.
class C3;
rand int x;
endclass
class M3;
rand C3 c1;
rand C3 c2;
constraint c {
c1.x == 11;
c2.x == 22;
}
function new();
c1 = new();
c2 = new();
endfunction
endclass
// Scenario 4 (global constraint owner with its own size-constrained array): the
// owner basic-randomizes first, the solver overrides last, and the size-only
// resize fallback still resizes from the solver-determined size.
class C4;
rand int x;
endclass
class A4;
rand C4 c;
rand int arr[];
constraint c_sub {c.x == 5;}
constraint c_size {arr.size() == 4;}
function new();
c = new();
endfunction
endclass
module t_constraint_global_subobj;
B1 b1;
SA2 a2;
B2 b2;
M3 m3;
C3 s3;
A4 a4;
int prevx, prevy, p3;
bit varyx, varyy, vary3;
initial begin
// Scenario 1: SA1 never randomized; standalone B1 must vary both fields.
b1 = new();
varyx = 0;
varyy = 0;
if (b1.randomize() != 1) $stop;
prevx = b1.c.x;
prevy = b1.c.y;
for (int i = 0; i < 20; i++) begin
if (b1.randomize() != 1) $stop;
if (b1.c.x != prevx) varyx = 1;
if (b1.c.y != prevy) varyy = 1;
prevx = b1.c.x;
prevy = b1.c.y;
end
if (!varyx || !varyy) begin
$display("ERROR: standalone holder fields stuck (varyx=%0d varyy=%0d)", varyx, varyy);
$stop;
end
// Scenario 2: randomize the owner (constraint applies) and a standalone
// holder (fields random) in the same design.
a2 = new();
if (a2.randomize() != 1) $stop;
if (a2.b.c.x != 123) begin
$display("ERROR: owner constraint not applied, a2.b.c.x=%0d", a2.b.c.x);
$stop;
end
b2 = new();
varyx = 0;
if (b2.randomize() != 1) $stop;
prevx = b2.c.x;
for (int i = 0; i < 20; i++) begin
if (b2.randomize() != 1) $stop;
if (b2.c.x != prevx) varyx = 1;
prevx = b2.c.x;
end
if (!varyx) begin
$display("ERROR: standalone holder x stuck while owner also randomized");
$stop;
end
// Scenario 3: two same-type sub-objects each pinned, plus standalone vary.
m3 = new();
if (m3.randomize() != 1) $stop;
if (m3.c1.x != 11) begin
$display("ERROR: m3.c1.x should be 11, got %0d", m3.c1.x);
$stop;
end
if (m3.c2.x != 22) begin
$display("ERROR: m3.c2.x should be 22, got %0d", m3.c2.x);
$stop;
end
s3 = new();
vary3 = 0;
if (s3.randomize() != 1) $stop;
p3 = s3.x;
for (int i = 0; i < 20; i++) begin
if (s3.randomize() != 1) $stop;
if (s3.x != p3) vary3 = 1;
p3 = s3.x;
end
if (!vary3) begin
$display("ERROR: standalone same-type x stuck");
$stop;
end
// Scenario 4: owner with a global constraint AND its own size constraint.
a4 = new();
if (a4.randomize() != 1) $stop;
if (a4.c.x != 5) begin
$display("ERROR: a4.c.x should be 5, got %0d", a4.c.x);
$stop;
end
if (a4.arr.size() != 4) begin
$display("ERROR: a4.arr.size() should be 4, got %0d", a4.arr.size());
$stop;
end
$write("*-* All Finished *-*\n");
$finish;
end
endmodule

81
test_regress/t/t_constraint_global_subobj_combined.v
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@ -1,81 +0,0 @@
// 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
class C;
rand int x;
rand int y;
endclass
class B;
rand C c;
function new();
c = new();
endfunction
endclass
class A;
rand B b;
constraint c_foo {b.c.x == 123;}
function new();
b = new();
endfunction
endclass
module t_constraint_global_subobj_combined;
B b;
A a;
int px, py;
bit xvar, yvar;
initial begin
// Same compilation randomizes BOTH the sub-object holder B standalone AND the
// global-constraint owner A. A leaf (C::x) is therefore solver-owned for A
// but must be freely randomized for B; both have to work at once (issue
// #7833).
b = new();
if (b.randomize() != 1) $stop;
px = b.c.x;
py = b.c.y;
xvar = 0;
yvar = 0;
for (int i = 0; i < 20; i++) begin
if (b.randomize() != 1) $stop;
if (b.c.x != px) xvar = 1;
if (b.c.y != py) yvar = 1;
px = b.c.x;
py = b.c.y;
end
if (!xvar) begin
$display("ERROR: standalone b.c.x not randomized (stuck)");
$stop;
end
if (!yvar) begin
$display("ERROR: standalone b.c.y not randomized (stuck)");
$stop;
end
a = new();
if (a.randomize() != 1) $stop;
py = a.b.c.y;
yvar = 0;
for (int i = 0; i < 20; i++) begin
if (a.randomize() != 1) $stop;
if (a.b.c.x != 123) begin
$display("ERROR: global constraint b.c.x == 123 not applied, got %0d", a.b.c.x);
$stop;
end
if (a.b.c.y != py) yvar = 1;
py = a.b.c.y;
end
if (!yvar) begin
$display("ERROR: a.b.c.y not randomized (stuck)");
$stop;
end
$write("*-* All Finished *-*\n");
$finish;
end
endmodule

21
test_regress/t/t_constraint_global_subobj_multi.py
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@ -1,21 +0,0 @@
#!/usr/bin/env python3
# DESCRIPTION: Verilator: Verilog Test driver/expect definition
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of either the GNU Lesser General Public License Version 3
# or the Perl Artistic License Version 2.0.
# SPDX-FileCopyrightText: 2026 Wilson Snyder
# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
import vltest_bootstrap
test.scenarios('simulator')
if not test.have_solver:
test.skip("No constraint solver installed")
test.compile()
test.execute()
test.passes()

63
test_regress/t/t_constraint_global_subobj_multi.v
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@ -1,63 +0,0 @@
// 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
class C;
rand int x;
endclass
class M;
rand C c1;
rand C c2;
constraint c {
c1.x == 11;
c2.x == 22;
}
function new();
c1 = new();
c2 = new();
endfunction
endclass
module t_constraint_global_subobj_multi;
C s;
M m;
int p;
bit vary;
initial begin
// Type C is randomized standalone AND used as two distinct sub-objects of M,
// each pinned by a global constraint. The two sub-objects share the same
// underlying rand variable, so each must keep its own write_var (issue #7833
// family).
s = new();
if (s.randomize() != 1) $stop;
p = s.x;
vary = 0;
for (int i = 0; i < 20; i++) begin
if (s.randomize() != 1) $stop;
if (s.x != p) vary = 1;
p = s.x;
end
if (!vary) begin
$display("ERROR: standalone C.x not randomized (stuck)");
$stop;
end
m = new();
if (m.randomize() != 1) $stop;
if (m.c1.x != 11) begin
$display("ERROR: m.c1.x should be 11, got %0d", m.c1.x);
$stop;
end
if (m.c2.x != 22) begin
$display("ERROR: m.c2.x should be 22, got %0d", m.c2.x);
$stop;
end
$write("*-* All Finished *-*\n");
$finish;
end
endmodule

21
test_regress/t/t_constraint_global_subobj_standalone.py
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@ -1,21 +0,0 @@
#!/usr/bin/env python3
# DESCRIPTION: Verilator: Verilog Test driver/expect definition
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of either the GNU Lesser General Public License Version 3
# or the Perl Artistic License Version 2.0.
# SPDX-FileCopyrightText: 2026 Wilson Snyder
# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
import vltest_bootstrap
test.scenarios('simulator')
if not test.have_solver:
test.skip("No constraint solver installed")
test.compile()
test.execute()
test.passes()

63
test_regress/t/t_constraint_global_subobj_standalone.v
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@ -1,63 +0,0 @@
// 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
class C;
rand int x;
rand int y;
endclass
class B;
rand C c;
function new();
c = new();
endfunction
endclass
class A;
rand B b;
constraint c_foo {b.c.x == 123;}
function new();
b = new();
endfunction
endclass
module t_constraint_global_subobj_standalone;
B b;
int px, py;
bit xvar, yvar;
initial begin
// Issue #7833: a standalone randomize() of B must randomize the nested
// sub-object fields c.x and c.y. Class A holds a global constraint that
// references type C through b.c.x, which used to flag C's fields as solved
// and skip them in B's basic randomization even though A is never
// randomized here.
b = new();
if (b.randomize() != 1) $stop;
px = b.c.x;
py = b.c.y;
xvar = 0;
yvar = 0;
for (int i = 0; i < 20; i++) begin
if (b.randomize() != 1) $stop;
if (b.c.x != px) xvar = 1;
if (b.c.y != py) yvar = 1;
px = b.c.x;
py = b.c.y;
end
if (!xvar) begin
$display("ERROR: b.c.x not randomized (stuck)");
$stop;
end
if (!yvar) begin
$display("ERROR: b.c.y not randomized (stuck)");
$stop;
end
$write("*-* All Finished *-*\n");
$finish;
end
endmodule