[clang-format] Parse Verilog if statements

This patch mainly handles treating `begin` as block openers.

While and for statements will be handled in another patch.

Reviewed By: HazardyKnusperkeks

Differential Revision: https://reviews.llvm.org/D123450

Author: eywdck2l

clang/docs/ClangFormat.rst

@@ -43,6 +43,17 @@ to format C/C++/Java/JavaScript/JSON/Objective-C/Protobuf/C# code.
     --assume-filename=<string>     - Override filename used to determine the language.
                                      When reading from stdin, clang-format assumes this
                                      filename to determine the language.
+                                     Unrecognized filenames are treated as C++.
+                                     supported:
+                                       CSharp: .cs
+                                       Java: .java
+                                       JavaScript: .mjs .js .ts
+                                       Json: .json
+                                       Objective-C: .m .mm
+                                       Proto: .proto .protodevel
+                                       TableGen: .td
+                                       TextProto: .textpb .pb.txt .textproto .asciipb
+                                       Verilog: .sv .svh .v .vh
     --cursor=<uint>                - The position of the cursor when invoking
                                      clang-format from an editor integration
     --dry-run                      - If set, do not actually make the formatting changes

clang/include/clang/Format/Format.h

@@ -2589,12 +2589,17 @@ struct FormatStyle {
     LK_TableGen,
     /// Should be used for Protocol Buffer messages in text format
     /// (https://developers.google.com/protocol-buffers/).
-    LK_TextProto
+    LK_TextProto,
+    /// Should be used for Verilog and SystemVerilog.
+    /// https://standards.ieee.org/ieee/1800/6700/
+    /// https://sci-hub.st/10.1109/IEEESTD.2018.8299595
+    LK_Verilog
   };
   bool isCpp() const { return Language == LK_Cpp || Language == LK_ObjC; }
   bool isCSharp() const { return Language == LK_CSharp; }
   bool isJson() const { return Language == LK_Json; }
   bool isJavaScript() const { return Language == LK_JavaScript; }
+  bool isVerilog() const { return Language == LK_Verilog; }
 
   /// Language, this format style is targeted at.
   /// \version 3.5
@@ -4285,6 +4290,8 @@ inline StringRef getLanguageName(FormatStyle::LanguageKind Language) {
     return "TableGen";
   case FormatStyle::LK_TextProto:
     return "TextProto";
+  case FormatStyle::LK_Verilog:
+    return "Verilog";
   default:
     return "Unknown";
   }

clang/lib/Format/Format.cpp

@@ -3471,6 +3471,12 @@ static FormatStyle::LanguageKind getLanguageByFileName(StringRef FileName) {
     return FormatStyle::LK_CSharp;
   if (FileName.endswith_insensitive(".json"))
     return FormatStyle::LK_Json;
+  if (FileName.endswith_insensitive(".sv") ||
+      FileName.endswith_insensitive(".svh") ||
+      FileName.endswith_insensitive(".v") ||
+      FileName.endswith_insensitive(".vh")) {
+    return FormatStyle::LK_Verilog;
+  }
   return FormatStyle::LK_Cpp;
 }