Permit assignment patterns as lvalues of assignments.

PiperOrigin-RevId: 325274727
chipsalliance · Aug 6, 2020 · 650c6cc · 650c6cc
1 parent c1db566
commit 650c6cc
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diff --git a/verilog/parser/verilog.y b/verilog/parser/verilog.y
@@ -5292,7 +5292,9 @@ signed_unsigned_opt
   | /* empty */
     { $$ = nullptr; }
   ;
+
 lpvalue
+  /* intended to cover 'net_lvalue' and 'variable_lvalue' in LRM */
   : reference_or_call
     { $$ = MakeTaggedNode(N::kLPValue, $1); }
     /* Unless functions can return by reference, calls should not be permitted
@@ -5304,9 +5306,16 @@ lpvalue
   /* TODO(fangism): For lpvalue, verify that $1 is of the form
    * '{' expression_list_proper '}' and that each item in the list is an lvalue.
    */
+  | assignment_pattern
+    /* for 'assignment_pattern_net_lvalue'
+     * and 'assignment_pattern_variable_lvalue'.
+     * TODO(fangism): verify that elements are lpvalue (not just any expr).
+     */
+    { $$ = MakeTaggedNode(N::kLPValue, $1); }
   | streaming_concatenation
     { $$ = MakeTaggedNode(N::kLPValue, $1); }
   ;
+
 cont_assign
   : lpvalue '=' expression
     { $$ = MakeTaggedNode(N::kNetVariableAssignment, $1, $2, $3); }

diff --git a/verilog/parser/verilog_parser_unittest.cc b/verilog/parser/verilog_parser_unittest.cc
@@ -619,6 +619,43 @@ static const char* kFunctionTests[] = {
     "function void unpack_id(utils_pkg::bytestream_t bytes);\n"
     "{<< byte {this.reserved, this.id}} = bytes;\n"
     "endfunction",
+    // concatenation lvalue
+    "module foo;\n"
+    "  initial begin\n"
+    "    {A, B, C} = bar;\n"
+    "  end\n"
+    "endmodule\n",
+    // nested concatenation lvalue
+    "module foo;\n"
+    "  initial begin\n"
+    "    {{A, B}, {C, D}} = bar;\n"
+    "  end\n"
+    "endmodule\n",
+    // assignment pattern lvalue
+    "module foo;\n"
+    "  initial begin\n"
+    "    '{A, B, C} = bar;\n"
+    "  end\n"
+    "endmodule\n",
+    // assignment pattern lvalue and rvalue
+    "module foo;\n"
+    "  initial begin\n"
+    "    '{A, B, C} = '{D, E, F};\n"
+    "  end\n"
+    "endmodule\n",
+    // nested assignment pattern lvalue
+    "module foo;\n"
+    "  initial begin\n"
+    "    '{'{A, B}, '{C, D}} = bar;\n"
+    "  end\n"
+    "endmodule\n",
+    // mixed nested lvalue
+    "module foo;\n"
+    "  initial begin\n"
+    "    '{{A, B}, {C, D}} = bar1;\n"
+    "    {'{E, F}, '{G, H}} = bar2;\n"
+    "  end\n"
+    "endmodule\n",
     // qualified expressions
     "function void scoper;\n"
     "  a = b::c;\n"