Revert "[parser] Optimize directive parsing especially for preparser"

This reverts commit 9d34fa0c.

Reason for revert: Breaking test-parsing tests, see
https://ci.chromium.org/p/v8/builders/luci.v8.ci/V8%20Linux%20gcc%204.8/22942
https://ci.chromium.org/p/v8/builders/luci.v8.ci/V8%20Win64%20-%20msvc/5731

Original change's description:
> [parser] Optimize directive parsing especially for preparser
> 
> - Avoid allocating AstRawString in the preparser
> - Use fast LiteralEquals to compare the directive.
> 
> Bug: chromium:901250
> Change-Id: I178aca812f6c0ffa28d7f48b707316a5a99a2ac0
> Reviewed-on: https://chromium-review.googlesource.com/c/1314570
> Commit-Queue: Toon Verwaest <verwaest@chromium.org>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#57217}

TBR=ishell@chromium.org,verwaest@chromium.org

Change-Id: I47381358c5a8e9c39fe2af6e72481ebfe9d74a55
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:901250
Reviewed-on: https://chromium-review.googlesource.com/c/1314577Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57218}

src/ast/ast-value-factory.h

@@ -235,6 +235,8 @@ class AstBigInt {
   F(this_function, ".this_function")            \
   F(throw, "throw")                             \
   F(undefined, "undefined")                     \
+  F(use_asm, "use asm")                         \
+  F(use_strict, "use strict")                   \
   F(value, "value")
 
 class AstStringConstants final {

src/parsing/parser-base.h

@@ -4589,25 +4589,16 @@ ParserBase<Impl>::ParseStatementList(StatementListT body,
 
   DCHECK(!impl()->IsNull(body));
 
-  while (peek() == Token::STRING) {
-    bool use_strict = false;
-    bool use_asm = false;
-
+  while (peek() == Token::STRING && (scanner()->HasLineTerminatorAfterNext() ||
+                                     Token::IsAutoSemicolon(PeekAhead()))) {
+    const AstRawString* symbol = scanner()->NextSymbol(ast_value_factory_);
     Scanner::Location token_loc = scanner()->peek_location();
-
-    if (scanner()->NextLiteralEquals("use strict")) {
-      use_strict = true;
-    } else if (scanner()->NextLiteralEquals("use asm")) {
-      use_asm = true;
-    }
-
-    StatementT stat = ParseStatementListItem();
-    body->Add(stat, zone_);
-    may_abort = false;
-
-    if (!impl()->IsStringLiteral(stat)) break;
-
-    if (use_strict) {
+    // The length of the token is used to distinguish between strings literals
+    // that evaluate equal to directives but contain either escape sequences
+    // (e.g., "use \x73trict") or line continuations (e.g., "use \(newline)
+    // strict").
+    if (symbol == ast_value_factory()->use_strict_string() &&
+        token_loc.end_pos - token_loc.beg_pos == sizeof("use strict") + 1) {
       // Directive "use strict" (ES5 14.1).
       RaiseLanguageMode(LanguageMode::kStrict);
       if (!scope()->HasSimpleParameters()) {
@@ -4619,7 +4610,8 @@ ParserBase<Impl>::ParseStatementList(StatementListT body,
                                 "use strict");
         return kLazyParsingComplete;
       }
-    } else if (use_asm) {
+    } else if (symbol == ast_value_factory()->use_asm_string() &&
+               token_loc.end_pos - token_loc.beg_pos == sizeof("use asm") + 1) {
       // Directive "use asm".
       impl()->SetAsmModule();
     } else {
@@ -4628,6 +4620,9 @@ ParserBase<Impl>::ParseStatementList(StatementListT body,
       // as appropriate. Ditto usages below.
       RaiseLanguageMode(LanguageMode::kSloppy);
     }
+    StatementT stat = ParseStatementListItem();
+    body->Add(stat, zone());
+    may_abort = false;
   }
 
   // Allocate a target stack to use for this set of source elements. This way,

src/parsing/scanner.h

@@ -260,8 +260,9 @@ class Scanner {
     Location(int b, int e) : beg_pos(b), end_pos(e) { }
     Location() : beg_pos(0), end_pos(0) { }
 
-    int length() const { return end_pos - beg_pos; }
-    bool IsValid() const { return beg_pos >= 0 && end_pos >= beg_pos; }
+    bool IsValid() const {
+      return beg_pos >= 0 && end_pos >= beg_pos;
+    }
 
     static Location invalid() { return Location(-1, -1); }
 
@@ -365,20 +366,6 @@ class Scanner {
            CurrentMatchesContextualEscaped(Token::LET);
   }
 
-  template <size_t N>
-  bool NextLiteralEquals(const char (&s)[N]) {
-    DCHECK_EQ(Token::STRING, peek());
-    // The length of the token is used to make sure the literal equals without
-    // taking escape sequences (e.g., "use \x73trict") or line continuations
-    // (e.g., "use \(newline) strict") into account.
-    if (!is_next_literal_one_byte()) return false;
-    if (peek_location().length() != N + 1) return false;
-
-    Vector<const uint8_t> next = next_literal_one_byte_string();
-    const char* chars = reinterpret_cast<const char*>(next.start());
-    return next.length() == N - 1 && strncmp(s, chars, N - 1) == 0;
-  }
-
   UnicodeCache* unicode_cache() const { return unicode_cache_; }
 
   // Returns the location of the last seen octal literal.

test/message/fail/directive.js

-// Copyright 2018 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-function f([a]) {
-  "use strict";
-}

test/message/fail/directive.out

-*%(basename)s:6: SyntaxError: Illegal 'use strict' directive in function with non-simple parameter list
-  "use strict";
-  ^^^^^^^^^^^^
-SyntaxError: Illegal 'use strict' directive in function with non-simple parameter list

test/mjsunit/regress/regress-directive.js

-// Copyright 2018 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-function f() {
-  'use strict'
-  in Number
-}
-
-f.arguments