linter: make constraint-name-style configurable

Up until now, constraint-name-style rule required constraint names to
end in '_c'. This makes it configurable, so that users can provide a
regular expression to specify what name style they want.

The default behaviour is still the same.

verilog/analysis/checkers/BUILD

@@ -1467,16 +1467,16 @@ cc_library(
         "//common/analysis:syntax-tree-lint-rule",
         "//common/analysis/matcher",
         "//common/analysis/matcher:bound-symbol-manager",
-        "//common/strings:naming-utils",
+        "//common/text:config-utils",
         "//common/text:symbol",
         "//common/text:syntax-tree-context",
         "//common/text:token-info",
         "//verilog/CST:constraints",
         "//verilog/CST:verilog-matchers",
         "//verilog/analysis:descriptions",
         "//verilog/analysis:lint-rule-registry",
-        "//verilog/parser:verilog-token-enum",
         "@com_google_absl//absl/strings",
+        "@com_googlesource_code_re2//:re2",
     ],
     alwayslink = 1,
 )

verilog/analysis/checkers/constraint_name_style_rule.cc

@@ -1,4 +1,4 @@
-// Copyright 2017-2020 The Verible Authors.
+// Copyright 2017-2023 The Verible Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -17,21 +17,19 @@
 #include <set>
 #include <string>
 
-#include "absl/strings/match.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/string_view.h"
 #include "common/analysis/lint_rule_status.h"
 #include "common/analysis/matcher/bound_symbol_manager.h"
 #include "common/analysis/matcher/matcher.h"
-#include "common/strings/naming_utils.h"
+#include "common/text/config_utils.h"
 #include "common/text/symbol.h"
 #include "common/text/syntax_tree_context.h"
 #include "common/text/token_info.h"
 #include "verilog/CST/constraints.h"
 #include "verilog/CST/verilog_matchers.h"
 #include "verilog/analysis/descriptions.h"
 #include "verilog/analysis/lint_rule_registry.h"
-#include "verilog/parser/verilog_token_enum.h"
 
 namespace verilog {
 namespace analysis {
@@ -44,50 +42,71 @@ using verible::matcher::Matcher;
 // Register ConstraintNameStyleRule.
 VERILOG_REGISTER_LINT_RULE(ConstraintNameStyleRule);
 
-static constexpr absl::string_view kMessage =
-    "Constraint names must by styled with lower_snake_case and end with _c.";
-
-const LintRuleDescriptor& ConstraintNameStyleRule::GetDescriptor() {
+const LintRuleDescriptor &ConstraintNameStyleRule::GetDescriptor() {
   static const LintRuleDescriptor d{
       .name = "constraint-name-style",
       .topic = "constraints",
       .desc =
-          "Check that constraint names follow the lower_snake_case "
-          "convention and end with _c.",
+          "Check that constraint names follow the required name style "
+          "specified by a regular expression.",
+      .param = {{"pattern", kSuffix}},
   };
   return d;
 }
 
-static const Matcher& ConstraintMatcher() {
+absl::Status ConstraintNameStyleRule::Configure(
+    absl::string_view configuration) {
+  std::string pattern = kSuffix;
+  absl::Status status = verible::ParseNameValues(
+      configuration, {{"pattern", verible::config::SetString(&pattern)}});
+
+  regex = std::make_unique<re2::RE2>(pattern, re2::RE2::Quiet);
+  if (!regex->ok()) {
+    std::cerr << "[ERR] Error parsing pattern " << std::quoted(pattern) << ": "
+              << regex->error()
+              << ". Falling back to the default configuration: "
+              << std::quoted(kSuffix);
+    regex = std::make_unique<re2::RE2>(kSuffix);
+  }
+
+  return status;
+}
+
+static const Matcher &ConstraintMatcher() {
   static const Matcher matcher(NodekConstraintDeclaration());
   return matcher;
 }
 
-void ConstraintNameStyleRule::HandleSymbol(const verible::Symbol& symbol,
-                                           const SyntaxTreeContext& context) {
+void ConstraintNameStyleRule::HandleSymbol(const verible::Symbol &symbol,
+                                           const SyntaxTreeContext &context) {
   verible::matcher::BoundSymbolManager manager;
   if (ConstraintMatcher().Matches(symbol, &manager)) {
     // Since an out-of-line definition is always followed by a forward
     // declaration somewhere else (in this case inside a class), we can just
-    // ignore all out-of-line definitions to  avoid duplicate lint errors on
+    // ignore all out-of-line definitions to avoid duplicate lint errors on
     // the same name.
     if (IsOutOfLineConstraintDefinition(symbol)) {
       return;
     }
 
-    const auto* identifier_token =
+    const auto *identifier_token =
         GetSymbolIdentifierFromConstraintDeclaration(symbol);
     if (!identifier_token) return;
 
     const absl::string_view constraint_name = identifier_token->text();
 
-    if (!verible::IsLowerSnakeCaseWithDigits(constraint_name) ||
-        !absl::EndsWith(constraint_name, "_c")) {
-      violations_.insert(LintViolation(*identifier_token, kMessage, context));
+    if (!RE2::FullMatch(constraint_name, *regex)) {
+      violations_.insert(
+          LintViolation(*identifier_token, FormatReason(), context));
     }
   }
 }
 
+std::string ConstraintNameStyleRule::FormatReason() const {
+  return absl::StrCat("Constraint names must obey the following regex: ",
+                      regex->pattern());
+}
+
 LintRuleStatus ConstraintNameStyleRule::Report() const {
   return LintRuleStatus(violations_, GetDescriptor());
 }

verilog/analysis/checkers/constraint_name_style_rule.h

@@ -1,4 +1,4 @@
-// Copyright 2017-2020 The Verible Authors.
+// Copyright 2017-2023 The Verible Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -15,34 +15,52 @@
 #ifndef VERIBLE_VERILOG_ANALYSIS_CHECKERS_CONSTRAINT_NAME_STYLE_RULE_H_
 #define VERIBLE_VERILOG_ANALYSIS_CHECKERS_CONSTRAINT_NAME_STYLE_RULE_H_
 
+#include <memory>
 #include <set>
 #include <string>
 
 #include "common/analysis/lint_rule_status.h"
 #include "common/analysis/syntax_tree_lint_rule.h"
 #include "common/text/symbol.h"
 #include "common/text/syntax_tree_context.h"
+#include "re2/re2.h"
 #include "verilog/analysis/descriptions.h"
 
 namespace verilog {
 namespace analysis {
 
-// ConstraintNameStyleRule check each constraint name follows the correct naming
-// convention.
-// The constraints should be named with lower_snake_case and end with _c.
+// Lower snake case, ends with `_c`
+#define kSuffix "([a-z0-9]+_)+c"
+
+// Lower snake case, starts with `c_`
+#define kPrefix "c+(_[a-z0-9]+)+"
+
+// ConstraintNameStyleRule checks that each constraint name follows the
+// specified naming convention.
+//
+// This convention is set by providing a regular expression to be matched
+// against.
+//
+// The default, `kSuffix` checks that the name is written in lower_snake_case
+// and ends with `_c`
 class ConstraintNameStyleRule : public verible::SyntaxTreeLintRule {
  public:
   using rule_type = verible::SyntaxTreeLintRule;
 
-  static const LintRuleDescriptor& GetDescriptor();
+  static const LintRuleDescriptor &GetDescriptor();
 
-  void HandleSymbol(const verible::Symbol& symbol,
-                    const verible::SyntaxTreeContext& context) final;
+  absl::Status Configure(absl::string_view configuration) final;
+  void HandleSymbol(const verible::Symbol &symbol,
+                    const verible::SyntaxTreeContext &context) final;
 
   verible::LintRuleStatus Report() const final;
 
  private:
   std::set<verible::LintViolation> violations_;
+  inline static std::unique_ptr<re2::RE2> regex =
+      std::make_unique<re2::RE2>(kSuffix);
+
+  std::string FormatReason() const;
 };
 
 }  // namespace analysis

verilog/analysis/checkers/constraint_name_style_rule_test.cc

@@ -1,4 +1,4 @@
-// Copyright 2017-2020 The Verible Authors.
+// Copyright 2017-2023 The Verible Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -29,6 +29,7 @@ namespace analysis {
 namespace {
 
 using verible::LintTestCase;
+using verible::RunConfiguredLintTestCases;
 using verible::RunLintTestCases;
 
 // Tests that ConstraintNameStyleRule correctly accepts valid names.
@@ -42,6 +43,7 @@ TEST(ConstraintNameStyleRuleTest, AcceptTests) {
       {"class foo; rand logic a; constraint foo_bar_c { a == 16; } endclass"},
       {"class foo; rand logic a; constraint foo2_c { a == 16; } endclass"},
       {"class foo; rand logic a; constraint foo_2_bar_c { a == 16; } endclass"},
+      {"class foo; rand logic a; constraint a_c { a == 16; } endclass"},
 
       /* Ignore out of line definitions */
       {"constraint classname::constraint_c { a <= b; }"},
@@ -51,6 +53,26 @@ TEST(ConstraintNameStyleRuleTest, AcceptTests) {
   RunLintTestCases<VerilogAnalyzer, ConstraintNameStyleRule>(kTestCases);
 }
 
+TEST(ConstraintNameStyleRuleTest, VariousPrefixTests) {
+  constexpr int kToken = SymbolIdentifier;
+  const std::initializer_list<LintTestCase> kTestCases = {
+      {"class foo; rand logic a; constraint c_foo { a == 16; } endclass"},
+      {"class foo; rand logic a; constraint c_a { a == 16; } endclass"},
+      {"class foo; rand logic a; constraint c_foo_bar { a == 16; } endclass"},
+      {"class foo; rand logic a; constraint ",
+       {kToken, "c_"},
+       " { a == 16; } endclass"},
+      {"class foo; rand logic a; constraint ",
+       {kToken, "no_suffix"},
+       " { a == 16; } endclass"},
+      {"class foo; rand logic a; constraint ",
+       {kToken, "suffix_ok_but_we_want_prefix_c"},
+       " { a == 16; } endclass"},
+  };
+  RunConfiguredLintTestCases<VerilogAnalyzer, ConstraintNameStyleRule>(
+      kTestCases, "pattern:" kPrefix);
+}
+
 // Tests that ConstraintNameStyleRule rejects invalid names.
 TEST(ConstraintNameStyleRuleTest, RejectTests) {
   constexpr int kToken = SymbolIdentifier;