Added an always_wrap_module_instantiations flag

verilog/formatting/format_style.h

@@ -116,6 +116,9 @@ struct FormatStyle : public verible::BasicFormatStyle {
   // Split with a \n end and else clauses
   bool wrap_end_else_clauses = false;
 
+  // Always split module instantiation's parameters and ports to new lines
+  bool always_wrap_module_instantiations = false;
+
   // -- Note: when adding new fields, add them in format_style_init.cc
 
   // TODO(fangism): introduce the following knobs:

verilog/formatting/format_style_init.cc

@@ -88,6 +88,10 @@ ABSL_FLAG(bool, compact_indexing_and_selections, true,
 ABSL_FLAG(bool, wrap_end_else_clauses, false,
           "Split end and else keywords into separate lines");
 
+ABSL_FLAG(
+    bool, always_wrap_module_instantiations, false,
+    "Always split module instantiation's parameters and ports to new lines");
+
 ABSL_FLAG(bool, port_declarations_right_align_packed_dimensions, false,
           "If true, packed dimensions in contexts with enabled alignment are "
           "aligned to the right.");
@@ -136,6 +140,7 @@ void InitializeFromFlags(FormatStyle *style) {
   STYLE_FROM_FLAG(expand_coverpoints);
   STYLE_FROM_FLAG(compact_indexing_and_selections);
   STYLE_FROM_FLAG(wrap_end_else_clauses);
+  STYLE_FROM_FLAG(always_wrap_module_instantiations);
 
 #undef STYLE_FROM_FLAG
 }

verilog/formatting/formatter_test.cc

@@ -15438,6 +15438,49 @@ TEST(FormatterEndToEndTest, VerilogFormatTest) {
   }
 }
 
+TEST(FormatterEndToEndTest, AlwaysWrapModuleInstantiation) {
+  static constexpr FormatterTestCase kTestCases[] = {
+      {"  module foo   ; bar bq();endmodule\n",
+       "module foo;\n"
+       "  bar bq ();\n"  // single instance
+       "endmodule\n"},
+      {"  module foo   ; bar bq(), bq2(  );endmodule\n",
+       "module foo;\n"
+       "  bar bq (), bq2 ();\n"  // multiple  empty instances, still fitting on
+                                 // one line
+       "endmodule\n"},
+      {"module foo; bar #(.N(N)) bq (.bus(bus));endmodule\n",
+       // instance parameter and port fits on line
+       "module foo;\n"
+       "  bar #(\n"
+       "      .N(N)\n"
+       "  ) bq (\n"
+       "      .bus(bus)\n"
+       "  );\n"
+       "endmodule\n"},
+      {"module foo; bar bq (.bus(bus));endmodule\n",
+       "module foo;\n"
+       "  bar bq (\n"
+       "      .bus(bus)\n"
+       "  );\n"
+       "endmodule\n"},
+  };
+  FormatStyle style;
+  style.column_limit = 40;
+  style.indentation_spaces = 2;
+  style.wrap_spaces = 4;
+  style.always_wrap_module_instantiations = true;
+  for (const auto& test_case : kTestCases) {
+    VLOG(1) << "code-to-format:\n" << test_case.input << "<EOF>";
+    std::ostringstream stream;
+    const auto status =
+        FormatVerilog(test_case.input, "<filename>", style, stream);
+    // Require these test cases to be valid.
+    EXPECT_OK(status) << status.message();
+    EXPECT_EQ(stream.str(), test_case.expected) << "code:\n" << test_case.input;
+  }
+}
+
 TEST(FormatterEndToEndTest, AutoInferAlignment) {
   static constexpr FormatterTestCase kTestCases[] = {
       {"", ""},

verilog/formatting/tree_unwrapper.cc

@@ -50,6 +50,7 @@
 #include "verilog/CST/functions.h"
 #include "verilog/CST/macro.h"
 #include "verilog/CST/statement.h"
+#include "verilog/CST/verilog_matchers.h"
 #include "verilog/CST/verilog_nonterminals.h"
 #include "verilog/formatting/verilog_token.h"
 #include "verilog/parser/verilog_parser.h"
@@ -834,7 +835,6 @@ void TreeUnwrapper::SetIndentationsAndCreatePartitions(
     case NodeEnum::kMacroGenericItem:
     case NodeEnum::kModuleHeader:
     case NodeEnum::kBindDirective:
-    case NodeEnum::kDataDeclaration:
     case NodeEnum::kGateInstantiation:
     case NodeEnum::kLoopHeader:
     case NodeEnum::kCovergroupHeader:
@@ -862,6 +862,16 @@ void TreeUnwrapper::SetIndentationsAndCreatePartitions(
       VisitIndentedSection(node, 0, PartitionPolicyEnum::kFitOnLineElseExpand);
       break;
     }
+    case NodeEnum::kDataDeclaration: {
+      const auto policy =
+          (style_.always_wrap_module_instantiations &&
+           (GetParamListFromDataDeclaration(node) ||
+            !SearchSyntaxTree(node, NodekPortActualList()).empty()))
+              ? PartitionPolicyEnum::kAlwaysExpand
+              : PartitionPolicyEnum::kFitOnLineElseExpand;
+      VisitIndentedSection(node, 0, policy);
+      break;
+    }
 
       // The following cases will always expand into their constituent
       // partitions:

verilog/tools/formatter/README.md

@@ -32,6 +32,8 @@ To pipe from stdin, use '-' as <file>.
       operator.); default: 4;
 
   Flags from verilog/formatting/format_style_init.cc:
+    --always_wrap_module_instantiations (Always split module instantiation's
+      parameters and ports to new lines); default: false;
     --assignment_statement_alignment (Format various assignments:
       {align,flush-left,preserve,infer}); default: infer;
     --case_items_alignment (Format case items: