Merge pull request #40626 from apple/revert-40623-revert_regex_literal_lexing_and_emission

Author: rxwei

cmake/modules/AddSwift.cmake

@@ -634,8 +634,13 @@ function(add_libswift_module module)
                         ""
                         "DEPENDS"
                         ${ARGN})
-  set(sources ${ALSM_UNPARSED_ARGUMENTS})
-  list(TRANSFORM sources PREPEND "${CMAKE_CURRENT_SOURCE_DIR}/")
+  set(raw_sources ${ALSM_UNPARSED_ARGUMENTS})
+  set(sources)
+  foreach(raw_source ${raw_sources})
+    get_filename_component(
+      raw_source "${raw_source}" REALPATH BASE_DIR "${CMAKE_CURRENT_SOURCE_DIR}")
+    list(APPEND sources "${raw_source}")
+  endforeach()
 
   set(target_name "LibSwift${module}")
 

include/swift/AST/ASTContext.h

@@ -621,7 +621,7 @@ class ASTContext final {
                                      KnownProtocolKind builtinProtocol,
                 llvm::function_ref<DeclName (ASTContext &ctx)> initName) const;
 
-  /// Retrieve _StringProcessing.Regex.init(_regexString: String).
+  /// Retrieve _StringProcessing.Regex.init(_regexString: String, version: Int).
   ConcreteDeclRef getRegexInitDecl(Type regexType) const;
 
   /// Retrieve the declaration of Swift.<(Int, Int) -> Bool.

include/swift/AST/Expr.h

@@ -966,18 +966,23 @@ class InterpolatedStringLiteralExpr : public LiteralExpr {
 class RegexLiteralExpr : public LiteralExpr {
   SourceLoc Loc;
   StringRef RegexText;
+  unsigned Version;
 
-  RegexLiteralExpr(SourceLoc loc, StringRef regexText, bool isImplicit)
+  RegexLiteralExpr(SourceLoc loc, StringRef regexText, unsigned version,
+                   bool isImplicit)
       : LiteralExpr(ExprKind::RegexLiteral, isImplicit), Loc(loc),
-        RegexText(regexText) {}
+        RegexText(regexText), Version(version) {}
 
 public:
   static RegexLiteralExpr *createParsed(ASTContext &ctx, SourceLoc loc,
-                                        StringRef regexText);
+                                        StringRef regexText, unsigned version);
 
   /// Retrieve the raw regex text.
   StringRef getRegexText() const { return RegexText; }
 
+  /// Retrieve the version of the regex string.
+  unsigned getVersion() const { return Version; }
+
   SourceRange getSourceRange() const { return Loc; }
 
   static bool classof(const Expr *E) {

include/swift/AST/KnownIdentifiers.def

@@ -252,6 +252,7 @@ IDENTIFIER(zero)
 // String processing
 IDENTIFIER(Regex)
 IDENTIFIER_(regexString)
+IDENTIFIER(version)
 IDENTIFIER_(StringProcessing)
 
 // Distributed actors

include/swift/Parse/ExperimentalRegexBridging.h

@@ -5,17 +5,43 @@
 extern "C" {
 #endif
 
-typedef const char *(* ParseRegexStrawperson)(const char *);
-
-void Parser_registerParseRegexStrawperson(ParseRegexStrawperson fn);
-bool Parser_hasParseRegexStrawperson();
+/// Attempt to lex a regex literal string. Takes the following arguments:
+///
+/// - CurPtrPtr: A pointer to the current pointer of lexer, which should be the
+///              start of the literal. This will be advanced to the point at
+///              which the lexer should resume, or will remain the same if this
+///              is not a regex literal.
+/// - BufferEnd: A pointer to the end of the buffer, which should not be lexed
+///              past.
+/// - ErrorOut: If an error is encountered, this will be set to the error
+///             string.
+///
+/// Returns: A bool indicating whether lexing was completely erroneous, and
+///          cannot be recovered from, or false if there either was no error,
+///          or there was a recoverable error.
+typedef bool(* RegexLiteralLexingFn)(/*CurPtrPtr*/ const char **,
+                                     /*BufferEnd*/ const char *,
+                                     /*ErrorOut*/ const char **);
+void Parser_registerRegexLiteralLexingFn(RegexLiteralLexingFn fn);
+
+/// Parse a regex literal string. Takes the following arguments:
+///
+/// - InputPtr: A null-terminated C string of the regex literal.
+/// - ErrorOut: A buffer accepting an error string upon error.
+/// - VersionOut: A buffer accepting a regex literal format version.
+/// - CaptureStructureOut: A buffer accepting a byte sequence representing the
+///                        capture structure of the literal.
+/// - CaptureStructureSize: The size of the capture structure buffer. Must be
+///                         greater than or equal to `strlen(InputPtr)`.
+typedef void(* RegexLiteralParsingFn)(/*InputPtr*/ const char *,
+                                      /*ErrorOut*/ const char **,
+                                      /*VersionOut*/ unsigned *,
+                                      /*CaptureStructureOut*/ char *,
+                                      /*CaptureStructureSize*/ unsigned);
+void Parser_registerRegexLiteralParsingFn(RegexLiteralParsingFn fn);
 
 #ifdef __cplusplus
 } // extern "C"
 #endif
 
 #endif // EXPERIMENTAL_REGEX_BRIDGING
-
-
-//const char* experimental_regex_strawperson(const char *in);
-

include/swift/Parse/Lexer.h

@@ -595,7 +595,9 @@ class Lexer {
   void lexStringLiteral(unsigned CustomDelimiterLen = 0);
   void lexEscapedIdentifier();
 
-  void lexRegexLiteral(const char *TokStart);
+  /// Attempt to lex a regex literal, returning true if a regex literal was
+  /// lexed, false if this is not a regex literal.
+  bool tryLexRegexLiteral(const char *TokStart);
 
   void tryLexEditorPlaceholder();
   const char *findEndOfCurlyQuoteStringLiteral(const char *,
@@ -612,9 +614,6 @@ class Lexer {
 
   /// Emit diagnostics for single-quote string and suggest replacement
   /// with double-quoted equivalent.
-  ///
-  /// Or, if we're in strawperson mode, we will emit a custom
-  /// error message instead, determined by the Swift library.
   void diagnoseSingleQuoteStringLiteral(const char *TokStart,
                                         const char *TokEnd);
 

lib/AST/ASTContext.cpp

@@ -1221,7 +1221,7 @@ ConcreteDeclRef ASTContext::getRegexInitDecl(Type regexType) const {
   auto *spModule = getLoadedModule(Id_StringProcessing);
   DeclName name(*const_cast<ASTContext *>(this),
                 DeclBaseName::createConstructor(),
-                {Id_regexString});
+                {Id_regexString, Id_version});
   SmallVector<ValueDecl *, 1> results;
   spModule->lookupQualified(getRegexType(), DeclNameRef(name),
                             NL_IncludeUsableFromInline, results);

lib/AST/Expr.cpp

@@ -2246,8 +2246,9 @@ SourceLoc TapExpr::getEndLoc() const {
 
 RegexLiteralExpr *
 RegexLiteralExpr::createParsed(ASTContext &ctx, SourceLoc loc,
-                               StringRef regexText) {
-  return new (ctx) RegexLiteralExpr(loc, regexText, /*implicit*/ false);
+                               StringRef regexText, unsigned version) {
+  return new (ctx) RegexLiteralExpr(loc, regexText, version,
+                                    /*implicit*/ false);
 }
 
 void swift::simple_display(llvm::raw_ostream &out, const ClosureExpr *CE) {

lib/Parse/Lexer.cpp

@@ -33,6 +33,13 @@
 
 #include <limits>
 
+// Regex lexing delivered via libSwift.
+#include "swift/Parse/ExperimentalRegexBridging.h"
+static RegexLiteralLexingFn regexLiteralLexingFn = nullptr;
+void Parser_registerRegexLiteralLexingFn(RegexLiteralLexingFn fn) {
+  regexLiteralLexingFn = fn;
+}
+
 using namespace swift;
 using namespace swift::syntax;
 
@@ -1951,36 +1958,46 @@ const char *Lexer::findEndOfCurlyQuoteStringLiteral(const char *Body,
   }
 }
 
-void Lexer::lexRegexLiteral(const char *TokStart) {
+bool Lexer::tryLexRegexLiteral(const char *TokStart) {
   assert(*TokStart == '\'');
 
-  bool HadError = false;
-  while (true) {
-    // Check if we reached the end of the literal without terminating.
-    if (CurPtr >= BufferEnd || *CurPtr == '\n' || *CurPtr == '\r') {
-      diagnose(TokStart, diag::lex_unterminated_regex);
-      return formToken(tok::unknown, TokStart);
-    }
+  // We need to have experimental string processing enabled, and have the
+  // parsing logic for regex literals available.
+  if (!LangOpts.EnableExperimentalStringProcessing || !regexLiteralLexingFn)
+    return false;
 
-    const auto *CharStart = CurPtr;
-    uint32_t CharValue = validateUTF8CharacterAndAdvance(CurPtr, BufferEnd);
-    if (CharValue == ~0U) {
-      diagnose(CharStart, diag::lex_invalid_utf8);
-      HadError = true;
-      continue;
-    }
-    if (CharValue == '\\' && (*CurPtr == '\'' || *CurPtr == '\\')) {
-      // Skip escaped delimiter or \.
-      CurPtr++;
-    } else if (CharValue == '\'') {
-      // End of literal, stop.
-      break;
-    }
+  // Ask libswift to try and lex a regex literal.
+  // - Ptr will not be advanced if this is not for a regex literal.
+  // - ErrStr will be set if there is any error to emit.
+  // - CompletelyErroneous will be set if there was an error that cannot be
+  //   recovered from.
+  auto *Ptr = TokStart;
+  const char *ErrStr = nullptr;
+  bool CompletelyErroneous = regexLiteralLexingFn(&Ptr, BufferEnd, &ErrStr);
+  if (ErrStr)
+    diagnose(TokStart, diag::regex_literal_parsing_error, ErrStr);
+
+  // If we didn't make any lexing progress, this isn't a regex literal and we
+  // should fallback to lexing as something else.
+  if (Ptr == TokStart)
+    return false;
+
+  // Update to point to where we ended regex lexing.
+  assert(Ptr > TokStart && Ptr <= BufferEnd);
+  CurPtr = Ptr;
+
+  // If the lexing was completely erroneous, form an unknown token.
+  if (CompletelyErroneous) {
+    assert(ErrStr);
+    formToken(tok::unknown, TokStart);
+    return true;
   }
-  if (HadError)
-    return formToken(tok::unknown, TokStart);
 
+  // Otherwise, we either had a successful lex, or something that was
+  // recoverable.
+  assert(ErrStr || CurPtr[-1] == '\'');
   formToken(tok::regex_literal, TokStart);
+  return true;
 }
 
 /// lexEscapedIdentifier:
@@ -2528,11 +2545,11 @@ void Lexer::lexImpl() {
 
   case '\'':
     // If we have experimental string processing enabled, and have the parsing
-    // logic for regex literals, lex a single quoted string as a regex literal.
-    if (LangOpts.EnableExperimentalStringProcessing &&
-        Parser_hasParseRegexStrawperson()) {
-      return lexRegexLiteral(TokStart);
-    }
+    // logic for regex literals, try to lex a single quoted string as a regex
+    // literal.
+    if (tryLexRegexLiteral(TokStart))
+      return;
+
     // Otherwise lex as a string literal and emit a diagnostic.
     LLVM_FALLTHROUGH;
   case '"':

lib/Parse/ParseRegex.cpp

@@ -22,38 +22,36 @@
 
 // Regex parser delivered via libSwift
 #include "swift/Parse/ExperimentalRegexBridging.h"
-static ParseRegexStrawperson parseRegexStrawperson = nullptr;
-void Parser_registerParseRegexStrawperson(ParseRegexStrawperson fn) {
-  parseRegexStrawperson = fn;
-}
-// Exposes the presence of the regex parsing function to the lexer.
-bool Parser_hasParseRegexStrawperson() {
-  return parseRegexStrawperson != nullptr;
+static RegexLiteralParsingFn regexLiteralParsingFn = nullptr;
+void Parser_registerRegexLiteralParsingFn(RegexLiteralParsingFn fn) {
+  regexLiteralParsingFn = fn;
 }
 
 using namespace swift;
 using namespace swift::syntax;
 
 ParserResult<Expr> Parser::parseExprRegexLiteral() {
   assert(Tok.is(tok::regex_literal));
-  assert(parseRegexStrawperson);
+  assert(regexLiteralParsingFn);
 
   SyntaxParsingContext LocalContext(SyntaxContext,
                                     SyntaxKind::RegexLiteralExpr);
-  // Strip off delimiters.
-  auto rawText = Tok.getText();
-  assert(rawText.front() == '\'' && rawText.back() == '\'');
-  auto regexText = rawText.slice(1, rawText.size() - 1);
+
+  auto regexText = Tok.getText();
 
   // Let the Swift library parse the contents, returning an error, or null if
   // successful.
   // TODO: We need to be able to pass back a source location to emit the error
   // at.
-  auto *errorStr = parseRegexStrawperson(regexText.str().c_str());
+  const char *errorStr = nullptr;
+  unsigned version;
+  regexLiteralParsingFn(regexText.str().c_str(), &errorStr, &version,
+                        /*captureStructureOut*/ nullptr,
+                        /*captureStructureSize*/ 0);
   if (errorStr)
     diagnose(Tok, diag::regex_literal_parsing_error, errorStr);
 
   auto loc = consumeToken();
   return makeParserResult(
-      RegexLiteralExpr::createParsed(Context, loc, regexText));
+      RegexLiteralExpr::createParsed(Context, loc, regexText, version));
 }