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Fix array size references in constraints (#8040) 

Signed-off-by: Kornel Uriasz <kuriasz@antmicro.com>
This commit is contained in:
Kornel Uriasz 2026-08-05 18:07:28 +02:00 committed by GitHub
parent 351d67c81e
commit 3fa88ae7f3
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GPG Key ID: B5690EEEBB952194
7 changed files with 325 additions and 27 deletions
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107
src/V3Randomize.cpp
View File

@ -2880,6 +2880,21 @@ class ConstraintExprVisitor final : public VNVisitor {
return;
}
// We've handled DYN_SIZE already if they should be randomized
if (nodep->method() == VCMethod::DYN_SIZE || nodep->method() == VCMethod::ASSOC_SIZE) {
AstNodeExpr* nodeExprp = nodep->fromp();
// Check if it is a pure chain of MemberSel ended with VarRef
// if not throw warning
while (VN_IS(nodeExprp, MemberSel)) {
nodeExprp = VN_AS(nodeExprp, MemberSel)->fromp();
}
if (VN_IS(nodeExprp, VarRef)) {
nodep->replaceWith(getConstFormat(nodep->cloneTreePure(false)));
VL_DO_DANGLING(nodep->deleteTree(), nodep);
return;
}
}
nodep->v3warn(CONSTRAINTIGN,
"Unsupported: randomizing this expression, treating as state");
nodep->user1(false);
@ -3310,6 +3325,7 @@ public:
// PUBLIC METHODS
AstArg* getArgs() const { return m_argsp; }
AstVar* getThisp() const { return m_thisp; }
void addFunctionArguments(AstNodeFTask* funcp) const {
for (AstArg* argp = getArgs(); argp; argp = VN_AS(argp->nextp(), Arg)) {
@ -4324,10 +4340,16 @@ class RandomizeVisitor final : public VNVisitor {
}
// Build a size >= 0 constraint expression (signed int size must be non-negative).
// Returns a new AstConstraintExpr with user1 bits set for solver visibility.
AstConstraintExpr* createSizeGteZeroConstraint(FileLine* const fl, AstVar* const sizeVarp) {
AstVarRef* const sizeVarRefp = new AstVarRef{fl, sizeVarp, VAccess::READ};
sizeVarRefp->user1(true);
AstGteS* const sizeGtep = new AstGteS{fl, sizeVarRefp, new AstConst{fl, 0}};
AstConstraintExpr* createSizeGteZeroConstraint(FileLine* const fl, AstVar* const sizeVarp,
AstNodeExpr* derefFromp = nullptr) {
AstNodeExpr* sizeNodeExprp = nullptr;
if (derefFromp) {
sizeNodeExprp = buildMemberSelExprp(derefFromp, sizeVarp);
} else {
sizeNodeExprp = new AstVarRef{fl, sizeVarp, VAccess::READ};
}
sizeNodeExprp->user1(true);
AstGteS* const sizeGtep = new AstGteS{fl, sizeNodeExprp, new AstConst{fl, 0}};
sizeGtep->user1(true);
return new AstConstraintExpr{fl, sizeGtep};
}
@ -4402,6 +4424,27 @@ class RandomizeVisitor final : public VNVisitor {
}
return commonp;
}
// Returns MemberSel chain, with deepest VarRef being reference to deepestVarp
AstNodeExpr* buildMemberSelExprp(AstNodeExpr* exprp, AstVar* deepestVarp) {
UASSERT_OBJ(VN_IS(exprp, MemberSel) || VN_IS(exprp, VarRef), exprp,
"Should be MemberSel or VarRef");
AstNodeExpr* resExprp = nullptr;
if (const AstMemberSel* memberSelp = VN_CAST(exprp, MemberSel)) {
resExprp = buildMemberSelExprp(memberSelp->fromp(), nullptr);
AstVar* varp = memberSelp->varp();
if (deepestVarp) varp = deepestVarp;
resExprp = new AstMemberSel{exprp->fileline(), resExprp, varp};
} else if (const AstVarRef* varRefp = VN_CAST(exprp, VarRef)) {
AstVar* varp = varRefp->varp();
if (deepestVarp) varp = deepestVarp;
resExprp = new AstVarRef{exprp->fileline(), VN_AS(varp->user2p(), NodeModule), varp,
VAccess::READWRITE};
}
resExprp->user1(true);
return resExprp;
}
void addBasicRandomizeBody(AstFunc* const basicRandomizep, AstClass* const nodep,
AstVar* randModeVarp) {
@ -6011,42 +6054,52 @@ class RandomizeVisitor final : public VNVisitor {
for (AstCMethodHard* const methodp : sizeMethodps) {
// Extract array variable from fromp (VarRef or MemberSel after capture)
AstVar* arrVarp = nullptr;
if (AstVarRef* const varRefp = VN_CAST(methodp->fromp(), VarRef)) {
arrVarp = varRefp->varp();
} else if (AstMemberSel* const memberSelp = VN_CAST(methodp->fromp(), MemberSel)) {
AstNodeExpr* const rootExprp = methodp->fromp();
if (AstMemberSel* memberSelp = VN_CAST(rootExprp, MemberSel)) {
arrVarp = memberSelp->varp();
while (VN_IS(memberSelp->fromp(), MemberSel)) {
memberSelp = VN_CAST(memberSelp->fromp(), MemberSel);
}
// Only variables that are part of object that randomize is called on shall be
// randomized (18.6.1), skip randomization if deepest variable is reference to
// __Vthis
const AstNodeExpr* fromp = memberSelp->fromp();
if (const AstVarRef* varRefp = VN_CAST(fromp, VarRef)) {
if (varRefp->varp() == captured.getThisp()) continue;
} else {
fromp->v3warn(E_UNSUPPORTED, "Unsupported: Unsupported size constraint "
"inside 'with' statement of type "
<< fromp->dtypep()->prettyTypeName());
}
} else if (AstVarRef* const varRefp = VN_CAST(rootExprp, VarRef)) {
arrVarp = varRefp->varp();
}
if (!arrVarp) continue;
// Only handle rand-declared dynamic/assoc array variables
if (!arrVarp->rand().isRandomizable()) continue;
// Do not randomize associative array size (IEEE 18.4)
if (VN_IS(arrVarp->dtypep()->skipRefp(), AssocArrayDType)) continue;
FileLine* const fl = methodp->fileline();
bool wasCreated = false;
AstVar* const sizeVarp
= createOrGetSizeVar(classp, arrVarp, fl, methodp->findIntDType(), wasCreated);
AstClass* const varClassp = VN_AS(arrVarp->user2p(), Class);
AstVar* const sizeVarp = createOrGetSizeVar(varClassp, arrVarp, fl,
methodp->findIntDType(), wasCreated);
// arrVarp and sizeVarp may live in a base class when the
// array is inherited; route VarRefs through their declaring
// class so V3Scope can resolve them.
AstNodeModule* const arrClassp = VN_AS(arrVarp->user2p(), NodeModule);
AstNodeModule* const sizeClassp = VN_AS(sizeVarp->user2p(), NodeModule);
if (wasCreated) {
// Generate resize for dynamic arrays/queues (not assoc arrays)
if (!VN_IS(arrVarp->dtypep()->skipRefp(), AssocArrayDType)) {
AstCMethodHard* const resizep = new AstCMethodHard{
fl, new AstVarRef{fl, arrClassp, arrVarp, VAccess::READWRITE},
VCMethod::DYN_RESIZE,
new AstVarRef{fl, sizeClassp, sizeVarp, VAccess::READ}};
resizep->dtypep(methodp->findVoidDType());
inlineResizeStmtsp
= AstNode::addNext(inlineResizeStmtsp, new AstStmtExpr{fl, resizep});
}
AstNodeExpr* const resizeVarRefp = buildMemberSelExprp(rootExprp, arrVarp);
AstNodeExpr* const sizeExprp = buildMemberSelExprp(rootExprp, sizeVarp);
// Append size >= 0 constraint so ConstraintExprVisitor processes it
capturedTreep->addNext(createSizeGteZeroConstraint(fl, sizeVarp));
capturedTreep->addNext(createSizeGteZeroConstraint(fl, sizeVarp, rootExprp));
AstCMethodHard* const resizep
= new AstCMethodHard{fl, resizeVarRefp, VCMethod::DYN_RESIZE, sizeExprp};
resizep->dtypep(methodp->findVoidDType());
inlineResizeStmtsp
= AstNode::addNext(inlineResizeStmtsp, new AstStmtExpr{fl, resizep});
}
AstVarRef* const sizeVarRefp
= new AstVarRef{fl, sizeClassp, sizeVarp, VAccess::READ};
sizeVarRefp->user1(true);
methodp->replaceWith(sizeVarRefp);
AstNodeExpr* const sizeNodeExprp = buildMemberSelExprp(rootExprp, sizeVarp);
methodp->replaceWith(sizeNodeExprp);
VL_DO_DANGLING(methodp->deleteTree(), methodp);
}
}

10
test_regress/t/t_constraint_arr_with_arrsize_unsup.out Normal file
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@ -0,0 +1,10 @@
%Error-UNSUPPORTED: t/t_constraint_arr_with_arrsize_unsup.v:27:14: Unsupported: Unsupported size constraint inside 'with' statement of type CLASSREFDTYPE 'Sub'
: ... note: In instance 't'
27 | if (i.s[0].arr.size > 0) {
| ^
... For error description see https://verilator.org/warn/UNSUPPORTED?v=latest
%Error: Internal Error: t/t_constraint_arr_with_arrsize_unsup.v:27:14: ../V3Randomize.cpp:#: Should be MemberSel or VarRef
: ... note: In instance 't'
27 | if (i.s[0].arr.size > 0) {
| ^
... This fatal error may be caused by the earlier error(s); resolve those first.

16
test_regress/t/t_constraint_arr_with_arrsize_unsup.py Executable file
View File

@ -0,0 +1,16 @@
#!/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('linter')
test.lint(fails=test.vlt_all, expect_filename=test.golden_filename)
test.passes()

44
test_regress/t/t_constraint_arr_with_arrsize_unsup.v Normal file
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@ -0,0 +1,44 @@
// DESCRIPTION: Verilator: Verilog Test module
//
// This file ONLY is placed under the Creative Commons Public Domain
// SPDX-FileCopyrightText: 2026 Antmicro
// SPDX-License-Identifier: CC0-1.0
class Sub;
rand int arr[];
function new();
arr = new[10];
endfunction
endclass
class Indep;
rand int val;
Sub s[];
function new();
s = new [10];
endfunction
endclass
class Cls;
function int randomize_gpr(Indep i);
return (i.randomize() with {
if (i.s[0].arr.size > 0) {
i.val inside {i.s[0].arr};
}
});
endfunction
endclass
module t;
Cls c;
Indep i;
initial begin
c = new;
i = new;
c.randomize_gpr(i);
end
endmodule

21
test_regress/t/t_constraint_dyn_size_class.py Executable file
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@ -0,0 +1,21 @@
#!/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()

128
test_regress/t/t_constraint_dyn_size_class.v Normal file
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@ -0,0 +1,128 @@
// DESCRIPTION: Verilator: Verilog Test module
//
// This file ONLY is placed under the Creative Commons Public Domain.
// SPDX-FileCopyrightText: 2026 Antmicro
// SPDX-License-Identifier: CC0-1.0
/*verilator lint_off*/
`define stop $stop
`define checkh(gotv,expv) do if ((gotv) !== (expv)) begin $write("%%Error: %s:%0d: got='h%x exp='h%x\n", `__FILE__,`__LINE__, (gotv), (expv)); `stop; end while(0);
`define check_range(gotv,minv,maxv) do if ((gotv) < (minv) || (gotv) > (maxv)) begin $write("%%Error: %s:%0d: got=%0d exp=%0d-%0d\n", `__FILE__,`__LINE__, (gotv), (minv), (maxv)); `stop; end while(0);
/*verilator lint_on*/
class SubSubClass;
rand int subVal;
rand int subArr[];
constraint c{
subArr.size < 10;
}
endclass
class SubClass;
rand int subVal;
rand int subArr[];
rand int assocArr[string] = '{ "test": 1, "test2" : 2 };
SubSubClass ssc;
function new();
ssc = new;
ssc.randomize();
endfunction
endclass
class IndepClass;
rand int val0;
rand int val1;
rand int val2;
rand SubClass sc;
function new();
sc = new;
endfunction
endclass
class BaseClass;
rand int arr[];
// Size-constrained array
constraint bc {
arr.size < 10;
arr.size > 5;
};
endclass
class ExtClass0 extends BaseClass;
function int randomize_gpr(IndepClass cls);
return (cls.randomize() with {
// If with arr.size on array, that's a field of class
// calling randomize() with
if (arr.size > 0) {
val0 inside {arr};
}
// If with arr.size on array thats a field inside subclass
// chain
if (cls.sc.ssc.subArr.size > 0 ) {
val1 == 'hDEADBEEF;
}
// Randomizable array size
sc.subArr.size > 25;
sc.subArr.size < 50;
// If with associative array size
if (sc.assocArr.size > 0) {
val2 == 'hCAFEBABE;
}
});
endfunction
endclass
class ExtClass1 extends BaseClass;
// Class that extends BaseClass and uses arr.size variable
constraint c {
unique{arr};
foreach(arr[i]) {
arr[i] != 0;
}
}
endclass
module t;
ExtClass0 ext0;
ExtClass1 ext1;
IndepClass indep;
initial begin
indep = new;
ext0 = new;
ext1 = new;
repeat(10) begin
`checkh(ext0.randomize(), 1);
`checkh(ext0.randomize(), 1);
`checkh(ext0.randomize_gpr(indep), 1);
`checkh(indep.val0 inside {ext0.arr}, 1);
`checkh(indep.val1, 'hDEADBEEF);
`checkh(indep.val2, 'hCAFEBABE);
`check_range(ext0.arr.size(), 5, 10);
`check_range(indep.sc.subArr.size(), 25, 50);
foreach (ext0.arr[i]) begin
if (ext0.arr[i] == 0) begin
`stop;
end
foreach (ext0.arr[j]) begin
if (i == j) continue;
if (ext0.arr[i] == ext0.arr[j]) begin
`stop;
end
end
end
end
$write("*-* All Finished *-*\n");
$finish();
end
endmodule

26
test_regress/t/t_randomize_with_constraint.v
View File

@ -10,11 +10,30 @@
`define check_range(gotv,minv,maxv) do if ((gotv) < (minv) || (gotv) > (maxv)) begin $write("%%Error: %s:%0d: got=%0d exp=%0d-%0d\n", `__FILE__,`__LINE__, (gotv), (minv), (maxv)); `stop; end while(0);
// verilog_format: on
class ArgCls;
rand int b;
endclass
class Cls;
rand int m_x;
rand int m_z;
int y = -1; // class member named 'y' intentionally shadows the caller arg
int lo = -100; // class member named 'lo' intentionally shadows the caller arg
rand int a[];
function new();
a = new [10];
endfunction
// Randomize array inside class that is argument
// with .size inside if
function automatic int randomize_subcls(ArgCls ac);
return ac.randomize() with {
if (a.size() > 0) {
ac.b == a.size();
}
};
endfunction
endclass
// 'y' is not in the list -> resolves to the caller arg (10), not class member (-1).
@ -76,8 +95,10 @@ endfunction
module t;
initial begin
Cls c;
ArgCls ac;
int i;
c = new;
ac = new;
repeat (20) begin
i = func_restricted(c, 10);
`checkd(i, 1);
@ -98,6 +119,11 @@ module t;
`check_range(c.m_x, 1, 7);
i = func_sequential(c, 6);
`checkd(i, 1);
i = c.randomize_subcls(ac);
`checkd(i, 1);
if (c.a.size() > 0) begin
`checkd(ac.b, c.a.size());
end
// Statement form: discards return value via void'.
void'(c.randomize() with (m_x) { m_x > 0; m_x < 5; });
`check_range(c.m_x, 1, 4);