Treat the x*1 generated by parsing a unary + as containing a dot.

Since we convert +x to x*1, we loose information about whether
the 1 was intended to be a floating point value for asm.js or not.

Mark the generated 1 as containing a dot (i.e. 1.0).

BUG= https://code.google.com/p/v8/issues/detail?id=4203
TEST=test-parser
R=rossberg@chromium.org,titzer@chromium.org
LOG=N

Review URL: https://codereview.chromium.org/1306683003

Cr-Commit-Position: refs/heads/master@{#30481}

src/parser.cc

@@ -626,7 +626,7 @@ Expression* ParserTraits::BuildUnaryExpression(Expression* expression,
   // Desugar '+foo' => 'foo*1'
   if (op == Token::ADD) {
     return factory->NewBinaryOperation(
-        Token::MUL, expression, factory->NewNumberLiteral(1, pos), pos);
+        Token::MUL, expression, factory->NewNumberLiteral(1, pos, true), pos);
   }
   // The same idea for '-foo' => 'foo*(-1)'.
   if (op == Token::SUB) {

test/cctest/test-parsing.cc

@@ -1134,10 +1134,19 @@ static void CheckParsesToNumber(const char* source, bool with_dot) {
   CHECK(fun->body()->length() == 1);
   CHECK(fun->body()->at(0)->IsReturnStatement());
   i::ReturnStatement* ret = fun->body()->at(0)->AsReturnStatement();
-  CHECK(ret->expression()->IsLiteral());
   i::Literal* lit = ret->expression()->AsLiteral();
+  if (lit != NULL) {
     const i::AstValue* val = lit->raw_value();
     CHECK(with_dot == val->ContainsDot());
+  } else if (with_dot) {
+    i::BinaryOperation* bin = ret->expression()->AsBinaryOperation();
+    CHECK(bin != NULL);
+    CHECK_EQ(i::Token::MUL, bin->op());
+    i::Literal* rlit = bin->right()->AsLiteral();
+    const i::AstValue* val = rlit->raw_value();
+    CHECK(with_dot == val->ContainsDot());
+    CHECK_EQ(1.0, val->AsNumber());
+  }
 }
 
 
@@ -1148,6 +1157,7 @@ TEST(ParseNumbers) {
   CheckParsesToNumber("134.e44", true);
   CheckParsesToNumber("134.44e44", true);
   CheckParsesToNumber(".44", true);
+  CheckParsesToNumber("+x", true);
 }