[api] Properly escape RegExp source

Change API RegExp::GetSource to return a string identical to ToString()
and RegExp.prototype.source.

Bug: v8:11693
Change-Id: I3d148883fe6f8a3ff49e552ddd72b1e92f52baf3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2900737Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Patrick Thier <pthier@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74854}

src/api/api.cc

@@ -7003,7 +7003,7 @@ MaybeLocal<v8::RegExp> v8::RegExp::NewWithBacktrackLimit(
 Local<v8::String> v8::RegExp::GetSource() const {
   i::Handle<i::JSRegExp> obj = Utils::OpenHandle(this);
   return Utils::ToLocal(
-      i::Handle<i::String>(obj->Pattern(), obj->GetIsolate()));
+      i::Handle<i::String>(obj->EscapedPattern(), obj->GetIsolate()));
 }
 
 // Assert that the static flags cast in GetFlags is valid.

src/objects/js-regexp-inl.h

@@ -73,6 +73,12 @@ String JSRegExp::Pattern() {
   return pattern;
 }
 
+String JSRegExp::EscapedPattern() {
+  DCHECK(this->source().IsString());
+  String pattern = String::cast(source());
+  return pattern;
+}
+
 Object JSRegExp::CaptureNameMap() {
   DCHECK(this->data().IsFixedArray());
   DCHECK(TypeSupportsCaptures(TypeTag()));

src/objects/js-regexp.h

@@ -115,6 +115,7 @@ class JSRegExp : public TorqueGeneratedJSRegExp<JSRegExp, JSObject> {
   inline int MaxRegisterCount() const;
   inline Flags GetFlags();
   inline String Pattern();
+  inline String EscapedPattern();
   inline Object CaptureNameMap();
   inline Object DataAt(int index) const;
   // Set implementation data after the object has been prepared.

test/cctest/test-api.cc

@@ -18941,6 +18941,13 @@ TEST(RegExp) {
   CHECK(re->GetSource()->Equals(context.local(), v8_str("foo")).FromJust());
   CHECK_EQ(v8::RegExp::kNone, re->GetFlags());
 
+  re = v8::RegExp::New(context.local(), v8_str("foo/bar"), v8::RegExp::kNone)
+           .ToLocalChecked();
+  CHECK(re->IsRegExp());
+  CHECK(
+      re->GetSource()->Equals(context.local(), v8_str("foo\\/bar")).FromJust());
+  CHECK_EQ(v8::RegExp::kNone, re->GetFlags());
+
   re = v8::RegExp::New(context.local(), v8_str("bar"),
                        static_cast<v8::RegExp::Flags>(v8::RegExp::kIgnoreCase |
                                                       v8::RegExp::kGlobal))
@@ -18973,6 +18980,11 @@ TEST(RegExp) {
   CHECK(re->GetSource()->Equals(context.local(), v8_str("quux")).FromJust());
   CHECK_EQ(v8::RegExp::kNone, re->GetFlags());
 
+  re = CompileRun("RegExp('qu/ux')").As<v8::RegExp>();
+  CHECK(re->IsRegExp());
+  CHECK(re->GetSource()->Equals(context.local(), v8_str("qu\\/ux")).FromJust());
+  CHECK_EQ(v8::RegExp::kNone, re->GetFlags());
+
   re = CompileRun("/quux/gm").As<v8::RegExp>();
   CHECK(re->IsRegExp());
   CHECK(re->GetSource()->Equals(context.local(), v8_str("quux")).FromJust());