Add UNPACKED warning to convert unpacked structs.

Changes

@@ -5,6 +5,8 @@ indicates the contributor was also the author of the fix; Thanks!
 
 * Verilator 3.854 devel
 
+***   Add UNPACKED warning to convert unpacked structs. [Jeremy Bennett]
+
 ****  Support vpi_get of vpiSuppressVal, bug687. [Varun Koyyalagunta]
 
 ****  Support vpi_get_time, bug688. [Varun Koyyalagunta]

bin/verilator

@@ -3225,6 +3225,13 @@ section for more details.
 Ignoring this warning will only slow simulations, it will simulate
 correctly.
 
+=item UNPACKED
+
+Warns that unpacked structs and unions are not supported.
+
+Ignoring this warning will make Verilator treat the structure as packed,
+which may make Verilator simulations differ from other simulators.
+
 =item UNSIGNED
 
 Warns that you are comparing a unsigned value in a way that implies it is

src/V3Ast.h

@@ -1597,6 +1597,7 @@ public:
     AstMemberDType* membersp() const { return op1p()->castMemberDType(); } // op1 = AstMember list
     void addMembersp(AstNode* nodep) { addNOp1p(nodep); }
     bool packed() const { return m_packed; }
+    bool packedUnsup() const { return true; }  // packed() but as don't support unpacked, presently all structs
     void clearCache() { m_members.clear(); }
     void repairMemberCache();
     AstMemberDType* findMember(const string& name) const {

src/V3Changed.cpp

@@ -89,7 +89,7 @@ private:
 	AstUnpackArrayDType* arrayp = varp->dtypeSkipRefp()->castUnpackArrayDType();
 	AstStructDType *structp = varp->dtypeSkipRefp()->castStructDType();
 	bool isArray = arrayp;
-	bool isStruct = structp && structp->packed();
+	bool isStruct = structp && structp->packedUnsup();
 	int elements = isArray ? arrayp->elementsConst() : 1;
 	if (isArray && (elements > DETECTARRAY_MAX_INDEXES)) {
 	    vscp->v3warn(E_DETECTARRAY, "Unsupported: Can't detect more than "<<cvtToStr(DETECTARRAY_MAX_INDEXES)

src/V3Error.h

@@ -93,6 +93,7 @@ public:
 	UNDRIVEN,	// No drivers
 	UNOPT,		// Unoptimizable block
 	UNOPTFLAT,	// Unoptimizable block after flattening
+	UNPACKED,	// Unsupported unpacked
 	UNSIGNED,	// Comparison is constant due to unsigned arithmetic
 	UNUSED,		// No receivers
 	VARHIDDEN,	// Hiding variable
@@ -129,7 +130,7 @@ public:
 	    "PINMISSING", "PINNOCONNECT",
 	    "REALCVT", "REDEFMACRO",
 	    "SELRANGE", "STMTDLY", "SYMRSVDWORD", "SYNCASYNCNET",
-	    "UNDRIVEN", "UNOPT", "UNOPTFLAT", "UNSIGNED", "UNUSED",
+	    "UNDRIVEN", "UNOPT", "UNOPTFLAT", "UNPACKED", "UNSIGNED", "UNUSED",
 	    "VARHIDDEN", "WIDTH", "WIDTHCONCAT",
 	    " MAX"
 	};

src/V3Width.cpp

@@ -1088,7 +1088,9 @@ private:
 	if (nodep->didWidthAndSet()) return;  // This node is a dtype & not both PRELIMed+FINALed
 	UINFO(5,"   NODECLASS "<<nodep<<endl);
 	//if (debug()>=9) nodep->dumpTree("-class-in--");
-	if (!nodep->packed()) nodep->v3error("Unsupported: Unpacked struct/union");
+	if (!nodep->packed()) {
+	    nodep->v3warn(UNPACKED, "Unsupported: Unpacked struct/union");
+	}
 	nodep->iterateChildren(*this);  // First size all members
 	nodep->repairMemberCache();
 	// Determine bit assignments and width

src/V3WidthSel.cpp

@@ -389,7 +389,7 @@ private:
 	VNumRange fromRange = fromdata.m_fromRange;
 	if (ddtypep->castBasicDType()
 	    || (ddtypep->castNodeClassDType()
-		&& ddtypep->castNodeClassDType()->packed())) {
+		&& ddtypep->castNodeClassDType()->packedUnsup())) {
 	    AstSel* newp = NULL;
 	    if (nodep->castSelPlus()) {
 		if (fromRange.littleEndian()) {

test_regress/t/t_struct_unpacked.pl

@@ -0,0 +1,18 @@
+#!/usr/bin/perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. 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.
+
+compile (
+    );
+
+execute (
+    check_finished=>1,
+    );
+
+ok(1);
+1;

test_regress/t/t_struct_unpacked.v

@@ -0,0 +1,26 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty, 2009 by Wilson Snyder.
+
+module x;
+
+   // verilator lint_off UNPACKED
+   typedef struct {
+      int 	  a;
+   } notpacked_t;
+   // verilator lint_on UNPACKED
+
+   typedef struct packed {
+      notpacked_t b;
+   } ispacked_t;
+
+   ispacked_t p;
+
+   initial begin
+      p.b = 1;
+      if (p.b != 1) $stop;
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+endmodule

test_regress/t/t_struct_unpacked_bad.pl

@@ -10,7 +10,8 @@ if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); di
 compile (
 	 fails=>$Self->{v3},
 	 expect=>
-q{%Error: t/t_struct_unpacked_bad.v:8: Unsupported: Unpacked struct/union
+q{%Warning-UNPACKED: t/t_struct_unpacked_bad.v:\d+: Unsupported: Unpacked struct/union
+%Warning-UNPACKED: Use .*
 .*%Error: Exiting due to.*},
 	 );
 

test_regress/t/t_struct_unpacked_bad.v

@@ -10,7 +10,15 @@ module x;
    } notpacked_t;
 
    typedef struct packed {
-      notpacked_t	a;
+      notpacked_t b;
    } ispacked_t;
 
+   ispacked_t p;
+
+   initial begin
+      p.b = 1;
+      if (p.b != 1) $stop;
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
 endmodule