[Parser][SE-0034] deprecate line directive in favor of #setline

Author: dduan

include/swift/AST/DiagnosticsParse.def

@@ -148,6 +148,9 @@ NOTE(note_in_decl_extension,none,
 WARNING(inout_as_attr_deprecated,none,
         "'inout' before a parameter name is deprecated, place it before the parameter type instead",
         ())
+WARNING(line_directive_style_deprecated,none,
+        "#line directive is deprecated, please use #setline instead",
+        ())
 
 ERROR(declaration_same_line_without_semi,none,
       "consecutive declarations on a line must be separated by ';'", ())

include/swift/Parse/Parser.h

@@ -695,8 +695,9 @@ class Parser {
                                             DeclAttributes &Attributes);
 
   ParserResult<IfConfigDecl> parseDeclIfConfig(ParseDeclOptions Flags);
-  /// Parse a #line directive.
-  ParserStatus parseLineDirective();
+  /// Parse a #line/#setline directive.
+  /// 'isLine = true' indicates parsing #line instead of #setline
+  ParserStatus parseLineDirective(bool isLine = false);
 
   void setLocalDiscriminator(ValueDecl *D);
 

include/swift/Parse/Tokens.def

@@ -171,6 +171,7 @@ POUND_KEYWORD(else)
 POUND_KEYWORD(elseif)
 POUND_KEYWORD(endif)
 POUND_KEYWORD(line)
+POUND_KEYWORD(setline)
 POUND_KEYWORD(available)
 POUND_KEYWORD(selector)
 

lib/Parse/ParseDecl.cpp

@@ -1706,10 +1706,11 @@ static bool isKeywordPossibleDeclStart(const Token &Tok) {
   case tok::kw_var:
   case tok::pound_if:
   case tok::identifier:
+  case tok::pound_setline:
     return true;
   case tok::pound_line:
-    // #line at the start of the line is a directive, #line within a line is
-    // an expression.
+    // #line at the start of the line is a directive, but it's deprecated.
+    // #line within a line is an expression.
     return Tok.isAtStartOfLine();
 
   case tok::kw_try:
@@ -2093,8 +2094,11 @@ ParserStatus Parser::parseDecl(SmallVectorImpl<Decl*> &Entries,
       }
       break;
     }
+    case tok::pound_setline:
+      Status = parseLineDirective(false);
+      break;
     case tok::pound_line:
-      Status = parseLineDirective();
+      Status = parseLineDirective(true);
       break;
 
     case tok::kw_func:
@@ -2556,15 +2560,20 @@ Parser::parseDeclExtension(ParseDeclOptions Flags, DeclAttributes &Attributes) {
   return DCC.fixupParserResult(status, ext);
 }
 
-ParserStatus Parser::parseLineDirective() {
-  SourceLoc Loc = consumeToken(tok::pound_line);
+ParserStatus Parser::parseLineDirective(bool isLine) {
+  SourceLoc Loc = consumeToken(isLine ? tok::pound_line
+                                      : tok::pound_setline);
+  if (isLine) {
+    diagnose(Loc, diag::line_directive_style_deprecated)
+        .fixItReplace(Loc, "#setline");
+  }
   bool WasInPoundLineEnvironment = InPoundLineEnvironment;
   if (WasInPoundLineEnvironment) {
     SourceMgr.closeVirtualFile(Loc);
     InPoundLineEnvironment = false;
   }
 
-  // #line\n returns to the main buffer.
+  // #setline\n returns to the main buffer.
   if (Tok.isAtStartOfLine()) {
     if (!WasInPoundLineEnvironment) {
       diagnose(Tok, diag::unexpected_line_directive);
@@ -2573,7 +2582,7 @@ ParserStatus Parser::parseLineDirective() {
     return makeParserSuccess();
   }
 
-  // #line 42 "file.swift"\n
+  // #setline 42 "file.swift"\n
   if (Tok.isNot(tok::integer_literal)) {
     diagnose(Tok, diag::expected_line_directive_number);
     return makeParserError();
@@ -2594,7 +2603,9 @@ ParserStatus Parser::parseLineDirective() {
     return makeParserError();
   }
 
-  auto Filename = getStringLiteralIfNotInterpolated(*this, Loc, Tok, "#line");
+  auto Filename = getStringLiteralIfNotInterpolated(*this, Loc, Tok,
+                                                    isLine ? "#line"
+                                                           : "#setline");
   if (!Filename.hasValue())
     return makeParserError();
 

lib/Parse/ParseStmt.cpp

@@ -47,6 +47,7 @@ bool Parser::isStartOfStmt() {
   case tok::kw_case:
   case tok::kw_default:
   case tok::pound_if:
+  case tok::pound_setline:
     return true;
 
   case tok::pound_line:
@@ -291,7 +292,7 @@ ParserStatus Parser::parseBraceItems(SmallVectorImpl<ASTNode> &Entries,
     PreviousHadSemi = false;
     if (isStartOfDecl()
         && Tok.isNot(tok::pound_if)
-        && Tok.isNot(tok::pound_line)) {
+        && Tok.isNot(tok::pound_setline)) {
       ParserStatus Status =
           parseDecl(TmpDecls, IsTopLevel ? PD_AllowTopLevel : PD_Default);
       if (Status.isError()) {
@@ -345,7 +346,11 @@ ParserStatus Parser::parseBraceItems(SmallVectorImpl<ASTNode> &Entries,
       }
 
     } else if (Tok.is(tok::pound_line)) {
-      ParserStatus Status = parseLineDirective();
+      ParserStatus Status = parseLineDirective(true);
+      BraceItemsStatus |= Status;
+      NeedParseErrorRecovery = Status.isError();
+    } else if (Tok.is(tok::pound_setline)) {
+      ParserStatus Status = parseLineDirective(false);
       BraceItemsStatus |= Status;
       NeedParseErrorRecovery = Status.isError();
     } else if (IsTopLevel) {
@@ -558,7 +563,11 @@ ParserResult<Stmt> Parser::parseStmt() {
   case tok::pound_line:
     if (LabelInfo) diagnose(LabelInfo.Loc, diag::invalid_label_on_stmt);
     if (tryLoc.isValid()) diagnose(tryLoc, diag::try_on_stmt, Tok.getText());
-    return parseLineDirective();
+    return parseLineDirective(true);
+  case tok::pound_setline:
+    if (LabelInfo) diagnose(LabelInfo.Loc, diag::invalid_label_on_stmt);
+    if (tryLoc.isValid()) diagnose(tryLoc, diag::try_on_stmt, Tok.getText());
+    return parseLineDirective(false);
   case tok::kw_while:
     if (tryLoc.isValid()) diagnose(tryLoc, diag::try_on_stmt, Tok.getText());
     return parseStmtWhile(LabelInfo);

test/Parse/line-directive.swift

@@ -25,3 +25,5 @@ public struct S { // expected-note{{in declaration of 'S'}}
 // expected-error@+1{{expected declaration}}
 / ###line 25 "line-directive.swift"
 }
+// expected-warning@+1{{#line directive is deprecated, please use #setline instead}}
+#line 32000 "troops_on_the_water"