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Change INITIALSTATIC to also report on processes, per IEEE (#7020)

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Wilson Snyder 2026-02-08 20:47:12 -05:00 committed by GitHub
parent ba194f3790
commit 5a236dd35d
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6 changed files with 70 additions and 56 deletions
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1
Changes
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@ -35,6 +35,7 @@ Verilator 5.045 devel
* Remove deprecated `--make cmake`.
* Change JSON dumps to not include booleans that are false (#6977).
* Change metacomment extra underscore error to BADVLTPRAGMA warning (#6968). [Geza Lore, Testorrent USA, Inc.]
* Change INITIALSTATIC to also report on processes, per IEEE.
* Optimize string temporaries to not be localized (#6969). [Geza Lore, Testorrent USA, Inc.]
* Optimize wide word shifts by multiple of word size (#6970). [Geza Lore, Testorrent USA, Inc.]
* Optimize concatenations that produce unused bits in DFG (#6971). [Geza Lore, Testorrent USA, Inc.]

15
docs/guide/warnings.rst
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@ -1022,13 +1022,20 @@ List Of Warnings
.. option:: IMPLICITSTATIC
Warns that the lifetime of a task or a function was not provided and so
was implicitly set to static. The warning is suppressed when no
variables inside the task or a function are assigned to.
an enclosed variable was implicitly set to static. The warning is
suppressed when no variables inside the task or a function are assigned
to.
Also warns that a process (e.g. "always" or "initial" statement) has
enclosed variables that were implicitly set to static.
IEEE 1800-2023 6.21 requires this error, though Verilator treats it by
default as a warning.
This is a warning because the static default differs from C++, differs
from class member function/tasks. Static is a more dangerous default
then automatic as static prevents the function from being reentrant,
which may be a source of bugs, and/or performance issues.
then automatic as static prevents the function or process from being
reentrant, which may be a source of bugs, and/or performance issues.
If the function is in a module, and does not require static behavior,
change it to "function automatic".

19
src/V3LinkParse.cpp
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@ -325,13 +325,12 @@ class LinkParseVisitor final : public VNVisitor {
&& !nodep->isIO()
&& !nodep->isParam()
// In task, or a procedure but not Initial/Final as executed only once
&& ((m_ftaskp && !m_ftaskp->lifetime().isStaticExplicit())
|| (m_procedurep && !VN_IS(m_procedurep, Initial)
&& !VN_IS(m_procedurep, Final)))) {
&& ((m_ftaskp && !m_ftaskp->lifetime().isStaticExplicit()) || m_procedurep)) {
if (VN_IS(m_modp, Module) && m_ftaskp) {
m_ftaskp->v3warn(
IMPLICITSTATIC,
"Function/task's lifetime implicitly set to static\n"
"Function/task's lifetime implicitly set to static;"
" variables made static (IEEE 1800-2023 6.21)\n"
<< m_ftaskp->warnMore() << "... Suggest use '" << m_ftaskp->verilogKwd()
<< " automatic' or '" << m_ftaskp->verilogKwd() << " static'\n"
<< m_ftaskp->warnContextPrimary() << '\n'
@ -339,12 +338,12 @@ class LinkParseVisitor final : public VNVisitor {
<< nodep->warnMore() << "... The initializer value will only be set once\n"
<< nodep->warnContextSecondary());
} else {
nodep->v3warn(IMPLICITSTATIC,
"Variable's lifetime implicitly set to static\n"
<< nodep->warnMore()
<< "... The initializer value will only be set once\n"
<< nodep->warnMore()
<< "... Suggest use 'static' before variable declaration'");
nodep->v3warn(
IMPLICITSTATIC,
"Variable's lifetime implicitly set to static (IEEE 1800-2023 6.21)\n"
<< nodep->warnMore() << "... The initializer value will only be set once\n"
<< nodep->warnMore()
<< "... Suggest use 'static' before variable declaration'");
}
}
if (!m_lifetimeAllowed && nodep->lifetime().isAutomatic()) {

8
test_regress/t/t_func_no_lifetime_bad.out
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@ -1,4 +1,4 @@
%Warning-IMPLICITSTATIC: t/t_func_no_lifetime_bad.v:26:17: Function/task's lifetime implicitly set to static
%Warning-IMPLICITSTATIC: t/t_func_no_lifetime_bad.v:26:17: Function/task's lifetime implicitly set to static; variables made static (IEEE 1800-2023 6.21)
: ... Suggest use 'function automatic' or 'function static'
26 | function int f_implicit_static();
| ^~~~~~~~~~~~~~~~~
@ -8,7 +8,7 @@
| ^~~
... For warning description see https://verilator.org/warn/IMPLICITSTATIC?v=latest
... Use "/* verilator lint_off IMPLICITSTATIC */" and lint_on around source to disable this message.
%Warning-IMPLICITSTATIC: t/t_func_no_lifetime_bad.v:31:9: Function/task's lifetime implicitly set to static
%Warning-IMPLICITSTATIC: t/t_func_no_lifetime_bad.v:31:9: Function/task's lifetime implicitly set to static; variables made static (IEEE 1800-2023 6.21)
: ... Suggest use 'task automatic' or 'task static'
31 | task t_implicit_static();
| ^~~~~~~~~~~~~~~~~
@ -16,12 +16,12 @@
: ... The initializer value will only be set once
32 | int cnt = 0;
| ^~~
%Warning-IMPLICITSTATIC: t/t_func_no_lifetime_bad.v:9:8: Variable's lifetime implicitly set to static
%Warning-IMPLICITSTATIC: t/t_func_no_lifetime_bad.v:9:8: Variable's lifetime implicitly set to static (IEEE 1800-2023 6.21)
: ... The initializer value will only be set once
: ... Suggest use 'static' before variable declaration'
9 | int cnt = 0;
| ^~~
%Warning-IMPLICITSTATIC: t/t_func_no_lifetime_bad.v:15:8: Variable's lifetime implicitly set to static
%Warning-IMPLICITSTATIC: t/t_func_no_lifetime_bad.v:15:8: Variable's lifetime implicitly set to static (IEEE 1800-2023 6.21)
: ... The initializer value will only be set once
: ... Suggest use 'static' before variable declaration'
15 | int cnt = 0;

40
test_regress/t/t_lint_implicitstatic_bad.out
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@ -1,31 +1,29 @@
%Warning-IMPLICITSTATIC: t/t_lint_implicitstatic_bad.v:16:9: Variable's lifetime implicitly set to static
%Warning-IMPLICITSTATIC: t/t_lint_implicitstatic_bad.v:20:9: Variable's lifetime implicitly set to static (IEEE 1800-2023 6.21)
: ... The initializer value will only be set once
: ... Suggest use 'static' before variable declaration'
16 | int implicit_warn = 1;
20 | int implicit_warn = 1;
| ^~~~~~~~~~~~~
... For warning description see https://verilator.org/warn/IMPLICITSTATIC?v=latest
... Use "/* verilator lint_off IMPLICITSTATIC */" and lint_on around source to disable this message.
%Warning-IMPLICITSTATIC: t/t_lint_implicitstatic_bad.v:20:16: Function/task's lifetime implicitly set to static
: ... Suggest use 'function automatic' or 'function static'
20 | function int f_implicit_static();
| ^~~~~~~~~~~~~~~~~
t/t_lint_implicitstatic_bad.v:21:9: ... Location of implicit static variable
: ... The initializer value will only be set once
21 | int cnt = 0;
| ^~~
%Warning-IMPLICITSTATIC: t/t_lint_implicitstatic_bad.v:25:8: Function/task's lifetime implicitly set to static
%Warning-IMPLICITSTATIC: t/t_lint_implicitstatic_bad.v:24:8: Function/task's lifetime implicitly set to static; variables made static (IEEE 1800-2023 6.21)
: ... Suggest use 'task automatic' or 'task static'
25 | task f_implicit_static();
24 | task t_implicit_static();
| ^~~~~~~~~~~~~~~~~
t/t_lint_implicitstatic_bad.v:26:9: ... Location of implicit static variable
t/t_lint_implicitstatic_bad.v:25:9: ... Location of implicit static variable
: ... The initializer value will only be set once
26 | int cnt = 0;
| ^~~
%Error: t/t_lint_implicitstatic_bad.v:25:8: Unsupported in C: Task has the same name as function: 'f_implicit_static'
25 | task f_implicit_static();
| ^~~~~~~~~~~~~~~~~
t/t_lint_implicitstatic_bad.v:20:16: ... Location of original declaration
20 | function int f_implicit_static();
25 | int t_no_has_init = 1;
| ^~~~~~~~~~~~~
%Warning-IMPLICITSTATIC: t/t_lint_implicitstatic_bad.v:32:16: Function/task's lifetime implicitly set to static; variables made static (IEEE 1800-2023 6.21)
: ... Suggest use 'function automatic' or 'function static'
32 | function int f_implicit_static();
| ^~~~~~~~~~~~~~~~~
... See the manual at https://verilator.org/verilator_doc.html?v=latest for more assistance.
t/t_lint_implicitstatic_bad.v:33:9: ... Location of implicit static variable
: ... The initializer value will only be set once
33 | int f_no_has_init = 1;
| ^~~~~~~~~~~~~
%Warning-IMPLICITSTATIC: t/t_lint_implicitstatic_bad.v:42:9: Variable's lifetime implicitly set to static (IEEE 1800-2023 6.21)
: ... The initializer value will only be set once
: ... Suggest use 'static' before variable declaration'
42 | int i_no_has_init = 1;
| ^~~~~~~~~~~~~
%Error: Exiting due to

43
test_regress/t/t_lint_implicitstatic_bad.v
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@ -8,32 +8,41 @@ module t (
input clk
);
initial begin
int static_ok = 1; // Obvious as is in initial
end
class C;
task t;
int c_no_has_init = 1; // Ok
automatic int c_automatic_has_init = 1; // Ok
static int c_static_has_init = 1; // Ok
endtask
endclass
always @(posedge clk) begin
int implicit_warn = 1; // <--- Warning: IMPLICITSTATIC
localparam int NO_WARN = 2; // No warning here
localparam int OK = 2; // Ok
end
function int f_implicit_static();
int cnt = 0; // <--- Warning: IMPLICIT STATIC
return ++cnt;
endfunction
task f_implicit_static();
int cnt = 0; // <--- Warning: IMPLICIT STATIC
++cnt;
task t_implicit_static();
int t_no_has_init = 1; // <--- Warning: IMPLICIT STATIC
automatic int t_automatic_has_init = 1; // Ok
static int t_static_has_init = 1; // Ok
localparam int ONE = 1; // Ok
++t_no_has_init;
endtask
function int f_no_implicit_static();
localparam int ONE = 1; // No warning here
function int f_implicit_static();
int f_no_has_init = 1; // <--- Warning: IMPLICIT STATIC
automatic int f_automatic_has_init = 1; // Ok
static int f_static_has_init = 1; // Ok
localparam int ONE = 1; // Ok
++f_no_has_init;
return ONE;
endfunction
task t_no_implicit_static();
localparam TWO = 2; // No warning here
endtask
initial begin
int i_no_has_init = 1; // <--- Warning: want explicit lifetime
automatic int i_automatic_has_init = 1; // Ok
static int i_static_has_init = 1; // Ok
$finish;
end
endmodule