From c9615fe19ca12b0f3ad867f6bf5bf4b9f4f40c7e Mon Sep 17 00:00:00 2001
From: IEncinas10 <ignacioencinasrubio@gmail.com>
Date: Thu, 4 May 2023 13:30:11 +0200
Subject: [PATCH] Add autofix for always_comb_blocking rule

Offer the user the posibility of changing the faulting non-blocking
assignment to a conforming blocking assignment.
---
 .../checkers/always_comb_blocking_rule.cc     | 24 ++++++++++++-------
 .../always_comb_blocking_rule_test.cc         | 22 ++++++++++++++++-
 2 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/verilog/analysis/checkers/always_comb_blocking_rule.cc b/verilog/analysis/checkers/always_comb_blocking_rule.cc
index 048da2b82..b1383188c 100644
--- a/verilog/analysis/checkers/always_comb_blocking_rule.cc
+++ b/verilog/analysis/checkers/always_comb_blocking_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.
@@ -33,6 +33,7 @@
 namespace verilog {
 namespace analysis {
 
+using verible::AutoFix;
 using verible::down_cast;
 using verible::LintRuleStatus;
 using verible::LintViolation;
@@ -46,7 +47,7 @@ VERILOG_REGISTER_LINT_RULE(AlwaysCombBlockingRule);
 static constexpr absl::string_view kMessage =
     "Use only blocking assignments in \'always_comb\' combinational blocks.";
 
-const LintRuleDescriptor& AlwaysCombBlockingRule::GetDescriptor() {
+const LintRuleDescriptor &AlwaysCombBlockingRule::GetDescriptor() {
   static const LintRuleDescriptor d{
       .name = "always-comb-blocking",
       .topic = "combinational-logic",
@@ -58,27 +59,32 @@ const LintRuleDescriptor& AlwaysCombBlockingRule::GetDescriptor() {
 }
 
 // Matches always_comb blocks.
-static const Matcher& AlwaysCombMatcher() {
+static const Matcher &AlwaysCombMatcher() {
   static const Matcher matcher(NodekAlwaysStatement(AlwaysCombKeyword()));
   return matcher;
 }
 
-void AlwaysCombBlockingRule::HandleSymbol(const verible::Symbol& symbol,
-                                          const SyntaxTreeContext& context) {
+void AlwaysCombBlockingRule::HandleSymbol(const verible::Symbol &symbol,
+                                          const SyntaxTreeContext &context) {
   verible::matcher::BoundSymbolManager manager;
 
   if (AlwaysCombMatcher().Matches(symbol, &manager)) {
-    for (const auto& match :
+    for (const auto &match :
          SearchSyntaxTree(symbol, NodekNonblockingAssignmentStatement())) {
       if (match.match->Kind() != verible::SymbolKind::kNode) continue;
 
-      const auto* node = down_cast<const verible::SyntaxTreeNode*>(match.match);
+      const auto *node =
+          down_cast<const verible::SyntaxTreeNode *>(match.match);
 
-      const verible::SyntaxTreeLeaf* leaf = verible::GetSubtreeAsLeaf(
+      const verible::SyntaxTreeLeaf *leaf = verible::GetSubtreeAsLeaf(
           *node, NodeEnum::kNonblockingAssignmentStatement, 1);
 
       if (leaf && leaf->get().token_enum() == TK_LE) {
-        violations_.insert(LintViolation(*leaf, kMessage, match.context));
+        violations_.insert(
+            LintViolation(*leaf, kMessage, match.context,
+                          {AutoFix("Use blocking assignment '=' instead of "
+                                   "nonblocking assignment '<='",
+                                   {leaf->get(), "="})}));
       }
     }
   }
diff --git a/verilog/analysis/checkers/always_comb_blocking_rule_test.cc b/verilog/analysis/checkers/always_comb_blocking_rule_test.cc
index 76a20d0fd..b1276476d 100644
--- a/verilog/analysis/checkers/always_comb_blocking_rule_test.cc
+++ b/verilog/analysis/checkers/always_comb_blocking_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.
@@ -30,6 +30,7 @@ namespace analysis {
 namespace {
 
 using verible::LintTestCase;
+using verible::RunApplyFixCases;
 using verible::RunLintTestCases;
 
 TEST(AlwaysCombBlockingRule, FunctionFailures) {
@@ -62,6 +63,25 @@ TEST(AlwaysCombBlockingRule, FunctionFailures) {
       kAlwaysCombBlockingTestCases);
 }
 
+TEST(AlwaysCombBlockingTest, AutoFixAlwaysCombBlocking) {
+  const std::initializer_list<verible::AutoFixInOut> kTestCases = {
+      {"module m;\nalways_comb a <= b;\nendmodule",
+       "module m;\nalways_comb a = b;\nendmodule"},
+      {"module m;\nalways_comb begin a <= b; end\nendmodule",
+       "module m;\nalways_comb begin a = b; end\nendmodule"},
+      {"module m;\nalways_comb begin if (sel == 0) a <= b; else a = 1'b0; "
+       "end\nendmodule",
+       "module m;\nalways_comb begin if (sel == 0) a = b; else a = 1'b0; "
+       "end\nendmodule"},
+      {"module m;\nalways_comb begin\n`ifdef RST\nf <= g;\n`else\nf = "
+       "1'b1;\n`endif\nend\nendmodule",
+       "module m;\nalways_comb begin\n`ifdef RST\nf = g;\n`else\nf = "
+       "1'b1;\n`endif\nend\nendmodule"},
+  };
+
+  RunApplyFixCases<VerilogAnalyzer, AlwaysCombBlockingRule>(kTestCases, "");
+}
+
 }  // namespace
 }  // namespace analysis
 }  // namespace verilog