luke
/
iverilog
mirror of https://github.com/steveicarus/iverilog.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Validate the generate "loop" expressions

This commit is contained in:
Cary R 2025-06-21 16:57:04 -07:00
parent adcb9f4e0d
commit a2ffbc307a
9 changed files with 137 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

81
elab_scope.cc
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2000-2024 Stephen Williams (steve@icarus.com)
* Copyright (c) 2000-2025 Stephen Williams (steve@icarus.com)
* Copyright CERN 2013 / Stephen Williams (steve@icarus.com)
*
* This source code is free software; you can redistribute it
@ -942,7 +942,7 @@ bool PGenerate::generate_scope_loop_(Design*des, NetScope*container)
while (cscope && !cscope->find_genvar(loop_index)) {
if (cscope->symbol_exists(loop_index)) {
cerr << get_fileline() << ": error: "
<< "generate loop variable '" << loop_index
<< "generate \"loop\" variable '" << loop_index
<< "' is not a genvar in this scope." << endl;
des->errors += 1;
return false;
@ -967,8 +967,16 @@ bool PGenerate::generate_scope_loop_(Design*des, NetScope*container)
NetExpr*init_ex = elab_and_eval(des, container, loop_init, -1, true);
NetEConst*init = dynamic_cast<NetEConst*> (init_ex);
if (init == 0) {
cerr << get_fileline() << ": error: Cannot evaluate genvar"
<< " init expression: " << *loop_init << endl;
cerr << get_fileline() << ": error: "
"Cannot evaluate generate \"loop\" initialization "
"expression: " << *loop_init << endl;
des->errors += 1;
return false;
}
if (! init->value().is_defined()) {
cerr << get_fileline() << ": error: "
<< "Generate \"loop\" initialization expression cannot have "
"undefined bits. given (" << *loop_init << ")." << endl;
des->errors += 1;
return false;
}
@ -979,16 +987,25 @@ bool PGenerate::generate_scope_loop_(Design*des, NetScope*container)
if (debug_scopes)
cerr << get_fileline() << ": debug: genvar init = " << genvar << endl;
container->genvar_tmp = loop_index;
container->genvar_tmp_val = genvar;
NetExpr*test_ex = elab_and_eval(des, container, loop_test, -1, true);
NetEConst*test = dynamic_cast<NetEConst*>(test_ex);
if (test == 0) {
cerr << get_fileline() << ": error: Cannot evaluate genvar"
<< " conditional expression: " << *loop_test << endl;
cerr << get_fileline() << ": error: Cannot evaluate generate \"loop\" "
"conditional expression: " << *loop_test << endl;
des->errors += 1;
return false;
}
if (! test->value().is_defined()) {
cerr << get_fileline() << ": error: "
"Generate \"loop\" conditional expression cannot have "
"undefined bits. given (" << *loop_test << ")." << endl;
des->errors += 1;
return false;
}
unsigned long loop_count = 1;
while (test->value().as_long()) {
// The actual name of the scope includes the genvar so
@ -996,10 +1013,17 @@ bool PGenerate::generate_scope_loop_(Design*des, NetScope*container)
// container. The format of using [] is part of the
// Verilog standard.
hname_t use_name (scope_name, genvar);
if (container->child(use_name)) {
cerr << get_fileline() << ": error: "
"Trying to create a duplicate generate scope named \""
<< use_name << "\"." << endl;
des->errors += 1;
return false;
}
if (debug_scopes)
cerr << get_fileline() << ": debug: "
<< "Create generated scope " << use_name << endl;
"Create generated scope " << use_name << endl;
NetScope*scope = new NetScope(container, use_name,
NetScope::GENBLOCK);
@ -1025,7 +1049,7 @@ bool PGenerate::generate_scope_loop_(Design*des, NetScope*container)
scope->set_parameter(loop_index, gp, *this);
if (debug_scopes)
cerr << get_fileline() << ": debug: "
<< "Create implicit localparam "
"Create implicit localparam "
<< loop_index << " = " << genvar_verinum << endl;
}
@ -1035,8 +1059,8 @@ bool PGenerate::generate_scope_loop_(Design*des, NetScope*container)
NetExpr*step_ex = elab_and_eval(des, container, loop_step, -1, true);
NetEConst*step = dynamic_cast<NetEConst*>(step_ex);
if (step == 0) {
cerr << get_fileline() << ": error: Cannot evaluate genvar"
<< " step expression: " << *loop_step << endl;
cerr << get_fileline() << ": error: Cannot evaluate generate "
"\"loop\" increment expression: " << *loop_step << endl;
des->errors += 1;
return false;
}
@ -1044,7 +1068,24 @@ bool PGenerate::generate_scope_loop_(Design*des, NetScope*container)
cerr << get_fileline() << ": debug: genvar step from "
<< genvar << " to " << step->value().as_long() << endl;
genvar = step->value().as_long();
if (! step->value().is_defined()) {
cerr << get_fileline() << ": error: "
"Generate \"loop\" increment expression cannot have "
"undefined bits, given (" << *loop_step << ")." << endl;
des->errors += 1;
return false;
}
long next_genvar;
next_genvar = step->value().as_long();
if (next_genvar == genvar) {
cerr << get_fileline() << ": error: "
<< "The generate \"loop\" is not incrementing. The "
"previous and next genvar values are ("
<< genvar << ")." << endl;
des->errors += 1;
return false;
}
genvar = next_genvar;
check_for_valid_genvar_value_(genvar);
container->genvar_tmp_val = genvar;
delete step;
@ -1052,6 +1093,24 @@ bool PGenerate::generate_scope_loop_(Design*des, NetScope*container)
test_ex = elab_and_eval(des, container, loop_test, -1, true);
test = dynamic_cast<NetEConst*>(test_ex);
ivl_assert(*this, test);
if (! test->value().is_defined()) {
cerr << get_fileline() << ": error: "
"The generate \"loop\" conditional expression cannot have "
"undefined bits. given (" << *loop_test << ")." << endl;
des->errors += 1;
return false;
}
// If there are half a million iterations this is likely an infinite loop!
if (loop_count > 500000) {
cerr << get_fileline() << ": error: "
<< "Probable infinite loop detected in generate \"loop\". "
"It has run for " << loop_count
<< " iterations." << endl;
des->errors += 1;
return false;
}
++loop_count;
}
// Clear the genvar_tmp field in the scope to reflect that the

1
ivtest/gold/br_gh1225a.gold Normal file
View File

@ -0,0 +1 @@
./ivltests/br_gh1225a.v:5: error: A generate "loop" requires the initialization genvar (gv2) to match the iteration genvar (gv1).

4
ivtest/gold/br_gh1225b.gold Normal file
View File

@ -0,0 +1,4 @@
./ivltests/br_gh1225b.v:5: error: 'named' has already been declared in this scope.
./ivltests/br_gh1225b.v:3: : It was declared here as a variable.
./ivltests/br_gh1225b.v:9: error: 'match' has already been declared in this scope.
./ivltests/br_gh1225b.v:8: : It was declared here as a generate block.

10
ivtest/gold/br_gh1225c.gold Normal file
View File

@ -0,0 +1,10 @@
./ivltests/br_gh1225c.v:3: error: The generate "loop" is not incrementing. The previous and next genvar values are (-1).
./ivltests/br_gh1225c.v:6: error: Trying to create a duplicate generate scope named "$gen2[0]".
./ivltests/br_gh1225c.v:9: error: Generate "loop" initialization expression cannot have undefined bits. given (1'bx).
./ivltests/br_gh1225c.v:12: error: Generate "loop" increment expression cannot have undefined bits, given ((gv4)+(1'bx)).
./ivltests/br_gh1225c.v:15: error: Generate "loop" conditional expression cannot have undefined bits. given (1'bx).
./ivltests/br_gh1225c.v:18: error: Unable to bind parameter `gv6' in `test'
./ivltests/br_gh1225c.v:18: error: Cannot evaluate generate "loop" initialization expression: (gv6)+('sd1)
./ivltests/br_gh1225c.v:21: error: Probable infinite loop detected in generate "loop". It has run for 500001 iterations.
./ivltests/br_gh1225c.v:24: error: Probable infinite loop detected in generate "loop". It has run for 500001 iterations.
9 error(s) during elaboration.

6
ivtest/ivltests/br_gh1225a.v Normal file
View File

@ -0,0 +1,6 @@
module test;
genvar gv1;
// initialization and increment genvars do not match
for (genvar gv2 = -1; -1; gv1 = -1);
endmodule

10
ivtest/ivltests/br_gh1225b.v Normal file
View File

@ -0,0 +1,10 @@
module test;
// This should conflict with the generate loops below.
reg named;
// scope name matches a register
for (genvar gv = 0; gv < 1; gv = gv + 1) begin:named; end;
// You cannot have generate blocks with the same name.
for (genvar gv = 0; gv < 1; gv = gv + 1) begin:match; end;
for (genvar gv = 0; gv < 1; gv = gv + 1) begin:match; end;
endmodule

25
ivtest/ivltests/br_gh1225c.v Normal file
View File

@ -0,0 +1,25 @@
module test;
// genvar does not increment.
for (genvar gv1 = -1; gv1 <= 2; gv1 = -1);
// genvar duplicates.
for (genvar gv2 = 0; gv2 >= 0; gv2 = gv2 + 64'h80000000);
// undefined value in initialization
for (genvar gv3 = 1'bx; gv3 <= 1; gv3 = gv3 + 1);
// undefined value in increment
for (genvar gv4 = 0; gv4 <= 1; gv4 = gv4 + 1'bx);
// undefined value in test condition
for (genvar gv5 = 0; 1'bx; gv5 = gv5 + 1);
// genvar used in RHS of initialization
for (genvar gv6 = gv6 + 1; gv <= 1; gv6 = gv6 + 1);
// loop forever
for (genvar gv7 = 0; 1'b1; gv7 = gv7 + 1);
// Almost forever
for (genvar gv8 = 0; gv8 >= 0; gv8 = gv8 + 1);
endmodule

3
ivtest/regress-vlg.list
View File

@ -367,6 +367,9 @@ br_gh1182 CE ivltests gold=br_gh1182.gold
br_gh1223a normal,-g2009 ivltests
br_gh1223b normal,-g2009 ivltests
br_gh1223c normal,-g2009 ivltests
br_gh1225a CE ivltests gold=br_gh1225a.gold
br_gh1225b CE ivltests gold=br_gh1225b.gold
br_gh1225c CE ivltests gold=br_gh1225c.gold
br_ml20150315 normal ivltests gold=br_ml_20150315.gold
br_ml20150321 CE ivltests
br_mw20171108 normal ivltests

8
pform.cc
View File

@ -1537,6 +1537,14 @@ void pform_start_generate_for(const struct vlltype&li,
pform_cur_generate->loop_test = test;
pform_cur_generate->loop_step = next;
if (strcmp(ident1, ident2)) {
cerr << li << ": error: "
<< "A generate \"loop\" requires the initialization genvar ("
<< ident1 << ") to match the iteration genvar ("
<< ident2 << ")." << endl;
error_count += 1;
}
delete[]ident1;
delete[]ident2;
}