Deprecate `--structs-packed` (#7222).

Changes

@@ -40,6 +40,7 @@ Verilator 5.047 devel
 * Add VPI callback support to --main (#7145).
 * Add V3LiftExpr pass to lower impure expressions and calls (#7141) (#7164). [Geza Lore, Testorrent USA, Inc.]
 * Add --func-recursion-depth CLI option (#7175) (#7179).
+* Deprecate `--structs-packed` (#7222).
 * Improve assignment-compatibility type check (#2843) (#5666) (#7052). [Pawel Kojma, Antmicro Ltd.]
 * Change array tracing to dump left index to right index (#7205). [Geza Lore, Testorrent USA, Inc.]
 * Change `--converge-limit` default to 10000 (#7209).

bin/verilator

@@ -498,7 +498,6 @@ detailed descriptions of these arguments.
     --no-std-package            Prevent parsing standard package
     --no-std-waiver             Prevent parsing standard lint waivers
     --no-stop-fail              Do not call $stop when assertion fails
-    --structs-packed            Convert all unpacked structures to packed structures
      -sv                        Enable SystemVerilog parsing
      +systemverilogext+<ext>    Synonym for +1800-2023ext+<ext>
     --threads <threads>         Enable multithreading

docs/guide/deprecations.rst

@@ -17,7 +17,15 @@ C++14 compiler support
    the Ubuntu LTS versions of GCC and clang use C++20 by default, estimated
    May 2028.)
 
+`--structs-packed` option
+   The :vlopt:`--structs-packed` option was introduced when Verilator was
+   first implementing unpacked structs. That feature has been stable now
+   for multiple years, so :vlopt:`--structs-packed` should no longer be
+   used. Thus :vlopt:`--structs-packed` will change to a no-operation flag
+   and the related :option:`UNPACKED` warning will never be issued no
+   sooner than September 2026.
+
 tcmalloc support
    Verilator currently supports the default malloc, tcmalloc, or jemalloc.
    As jemalloc has better performance, support for tcmalloc may be removed
-   no sooner than January 2026.
+   no sooner than January 2027.

docs/guide/exe_verilator.rst

@@ -1682,6 +1682,8 @@ Summary:
 
 .. option:: --structs-packed
 
+   Deprecated; discontinue use of this option.
+
    Converts all unpacked structures to packed structures, and issues an
    :option:`UNPACKED` warning. Specifying this option allows for backward
    compatibility with versions before Verilator 5.006, when Verilator would

src/V3Options.cpp

@@ -1742,7 +1742,10 @@ void V3Options::parseOptsList(FileLine* fl, const string& optdir, int argc,
     DECL_OPTION("-std-package", OnOff, &m_stdPackage);
     DECL_OPTION("-std-waiver", OnOff, &m_stdWaiver);
     DECL_OPTION("-stop-fail", OnOff, &m_stopFail);
-    DECL_OPTION("-structs-packed", OnOff, &m_structsPacked);
+    DECL_OPTION("-structs-packed", CbOnOff, [this, fl](bool flag) {
+        m_structsPacked = flag;
+        fl->v3warn(DEPRECATED, "Option --structs-packed is deprecated, avoid use");
+    }).undocumented();
     DECL_OPTION("-sv", CbCall, [this]() { m_defaultLanguage = V3LangCode::L1800_2023; });
 
     DECL_OPTION("-no-threads", CbCall, [this, fl]() {

test_regress/t/t_dist_docs_options.py

@@ -20,6 +20,7 @@ Doc_Waivers = [
     '-order-clock-delay',  # Deprecated
     '-pp-comments',  # Deprecated
     '-prof-threads',  # Deprecated
+    '-structs-packed',  # Deprecated
     '-xml-only',  # Removed
     '-xml-output',  # Removed
 ]

test_regress/t/t_flag_structs_packed.out

@@ -0,0 +1,3 @@
+%Warning-DEPRECATED: Option --structs-packed is deprecated, avoid use
+                     ... For warning description see https://verilator.org/warn/DEPRECATED?v=latest
+                     ... Use "/* verilator lint_off DEPRECATED */" and lint_on around source to disable this message.

test_regress/t/t_flag_structs_packed.py

@@ -11,7 +11,7 @@ import vltest_bootstrap
 
 test.scenarios('linter')
 
-test.compile(verilator_flags2=['--structs-packed'])
+test.compile(verilator_flags2=['-Wno-fatal', '--structs-packed'], expect_filename=test.golden_filename)
 
 test.execute()
 

test_regress/t/t_structu_dataType_assignment.py

@@ -9,9 +9,9 @@
 
 import vltest_bootstrap
 
-test.scenarios('simulator')
+test.scenarios('simulator_st')
 
-test.compile(verilator_flags2=['--structs-packed'])
+test.compile(verilator_flags2=['-Wno-DEPRECATED', '--structs-packed'])
 
 test.execute()
 

test_regress/t/t_structu_dataType_assignment_bad.py

@@ -11,6 +11,6 @@ import vltest_bootstrap
 
 test.scenarios('linter')
 
-test.lint(verilator_flags2=['--structs-packed'], fails=True, expect_filename=test.golden_filename)
+test.lint(fails=True, expect_filename=test.golden_filename)
 
 test.passes()