C++: Parse emit/Q_EMIT properly

The parser now understands emit/Q_EMIT as an expression statement.

Also, the recent fixes in the preprocessor introduced a side-effect
in the hanlding of code such as: emit signal(); Member signal started
being treated as a local use (parsed as a declaration) and possibily
being highlighted as unused variable.

Previously that worked by accident since there was an inconsistency
in the preprocessor on which only object-like macros were being
expanded even when the "no expand" flag was set. Then, the code
mentioned above was being parsed as an expression, what kind of worked.

Change-Id: I47a68ed4c1c1702872620b8ed7c7264fb0997034
Reviewed-by: Roberto Raggi <roberto.raggi@nokia.com>

src/libs/3rdparty/cplusplus/Keywords.cpp

@@ -136,6 +136,13 @@ static inline int classify4(const char *s, bool q, bool) {
         }
       }
     }
+    else if (q && s[1] == 'm') {
+      if (s[2] == 'i') {
+        if (s[3] == 't') {
+          return T_EMIT;
+        }
+      }
+    }
   }
   else if (s[0] == 'g') {
     if (s[1] == 'o') {
@@ -417,6 +424,19 @@ static inline int classify6(const char *s, bool q, bool) {
       }
     }
   }
+  else if (q && s[0] == 'Q') {
+    if (s[1] == '_') {
+      if (s[2] == 'E') {
+        if (s[3] == 'M') {
+          if (s[4] == 'I') {
+            if (s[5] == 'T') {
+              return T_Q_EMIT;
+            }
+          }
+        }
+      }
+    }
+  }
   else if (s[0] == 'r') {
     if (s[1] == 'e') {
       if (s[2] == 't') {

src/libs/3rdparty/cplusplus/Parser.cpp

@@ -2947,6 +2947,23 @@ bool Parser::parseStatement(StatementAST *&node)
         node = ast;
     } return true;
 
+    case T_EMIT:
+    case T_Q_EMIT: {
+        // Simply skip the emit token and parse as an expression statement - no strong
+        // reason to have an specific ast type.
+        consumeToken();
+        ExpressionAST *expression = 0;
+        if (parsePostfixExpression(expression)) {
+            ExpressionStatementAST *ast = new (_pool) ExpressionStatementAST;
+            ast->expression = expression;
+            match(T_SEMICOLON, &ast->semicolon_token);
+            node = ast;
+            return true;
+        }
+        error(cursor(), "expected statement");
+        return false;
+    }
+
     default:
         if (LA() == T_IDENTIFIER && LA(2) == T_COLON)
             return parseLabeledStatement(node);

src/libs/3rdparty/cplusplus/Token.cpp

@@ -71,10 +71,10 @@ static const char *token_names[] = {
     ("@synchronized"), ("@synthesize"), ("@throw"), ("@try"),
 
     // Qt keywords
-    ("SIGNAL"), ("SLOT"), ("Q_SIGNAL"), ("Q_SLOT"), ("signals"), ("slots"),
+    ("emit"), ("SIGNAL"), ("SLOT"), ("Q_SIGNAL"), ("Q_SLOT"), ("signals"), ("slots"),
     ("Q_FOREACH"), ("Q_D"), ("Q_Q"),
     ("Q_INVOKABLE"), ("Q_PROPERTY"), ("T_Q_PRIVATE_PROPERTY"),
-    ("Q_INTERFACES"), ("Q_ENUMS"), ("Q_FLAGS"),
+    ("Q_INTERFACES"), ("Q_EMIT"), ("Q_ENUMS"), ("Q_FLAGS"),
     ("Q_PRIVATE_SLOT"), ("Q_DECLARE_INTERFACE"), ("Q_OBJECT"), ("Q_GADGET"),
 
 };

src/libs/3rdparty/cplusplus/Token.h

@@ -217,7 +217,8 @@ enum Kind {
     T_FIRST_QT_KEYWORD,
 
     // Qt keywords
-    T_SIGNAL = T_FIRST_QT_KEYWORD,
+    T_EMIT = T_FIRST_QT_KEYWORD,
+    T_SIGNAL,
     T_SLOT,
     T_Q_SIGNAL,
     T_Q_SLOT,
@@ -230,6 +231,7 @@ enum Kind {
     T_Q_PROPERTY,
     T_Q_PRIVATE_PROPERTY,
     T_Q_INTERFACES,
+    T_Q_EMIT,
     T_Q_ENUMS,
     T_Q_FLAGS,
     T_Q_PRIVATE_SLOT,

src/libs/cplusplus/pp-engine.cpp

@@ -1813,6 +1813,10 @@ bool Preprocessor::isQtReservedWord(const ByteArrayRef &macroId)
         return true;
     else if (size == 5 && macroId.at(0) == 's' && macroId == "slots")
         return true;
+    else if (size == 4 && macroId.at(0) == 'e' && macroId == "emit")
+        return true;
+    else if (size == 6 && macroId.at(0) == 'Q' && macroId == "Q_EMIT")
+        return true;
     return false;
 }