diff --git a/components/codetools/ccodeparsertool.pas b/components/codetools/ccodeparsertool.pas
index e29dab5ae8..0ec42b9efb 100644
--- a/components/codetools/ccodeparsertool.pas
+++ b/components/codetools/ccodeparsertool.pas
@@ -382,6 +382,7 @@ function TCCodeParserTool.DirectiveToken: boolean;
   procedure ReadExpression;
   var
     BracketLevel: Integer;
+    NeedBracket: Boolean;
   begin
     BracketLevel:=0;
     repeat
@@ -407,16 +408,22 @@ function TCCodeParserTool.DirectiveToken: boolean;
         // valid operator
       end else if IsIdentChar[Src[AtomStart]] then begin
         if AtomIs('defined') then begin
-          // read  defined(macro)
-          ReadRawNextCAtom(Src,SrcPos,AtomStart);
-          if not AtomIsChar('(') then
-            RaiseExpectedButAtomFound('(');
+          //    read  defined(macro)
+          // or read  defined macro
           ReadRawNextCAtom(Src,SrcPos,AtomStart);
+          if AtomIsChar('(') then begin
+            NeedBracket:=true;
+            ReadRawNextCAtom(Src,SrcPos,AtomStart);
+          end else begin
+            NeedBracket:=false;
+          end;
           if not AtomIsIdentifier then
             RaiseExpectedButAtomFound('macro');
-          ReadRawNextCAtom(Src,SrcPos,AtomStart);
-          if not AtomIsChar(')') then
-            RaiseExpectedButAtomFound(')');
+          if NeedBracket then begin
+            ReadRawNextCAtom(Src,SrcPos,AtomStart);
+            if not AtomIsChar(')') then
+              RaiseExpectedButAtomFound(')');
+          end;
         end else begin
           // constant
         end;
diff --git a/components/codetools/expreval.pas b/components/codetools/expreval.pas
index 651ded0e46..6f1a74f86d 100644
--- a/components/codetools/expreval.pas
+++ b/components/codetools/expreval.pas
@@ -19,6 +19,7 @@
     invalid).
     The function Eval evaluates expressions and understands the operators
       AND, OR, XOR, NOT, (, ), =, <, >, <=, >=, <>
+      defined()
 }
 unit ExprEval;
 
@@ -85,6 +86,23 @@ type
     procedure WriteDebugReport;
   end;
 
+  { TExpressionSolver
+    Checks if expression is always true 1, always false 0, or something }
+
+  TExpressionSolver = class
+  public
+    //Defines: TStringToStringTree;
+    //Undefines: TStringToStringTree;
+    ErrorMsg: string; // last error message
+    ErrorPos: integer;// last error position
+    constructor Create;
+    destructor Destroy; override;
+    function Solve(const Expr: string; out ExprResult: string): boolean;
+    function Solve(const Src: string; StartPos, EndPos: integer;
+                  out ExprResult: string): boolean;
+  end;
+
+
 implementation
 
 var
@@ -734,6 +752,65 @@ begin
     dbgs(ConsistencyCheck));
 end;
 
+
+{ TExpressionSolver }
+
+constructor TExpressionSolver.Create;
+begin
+
+end;
+
+destructor TExpressionSolver.Destroy;
+begin
+  inherited Destroy;
+end;
+
+function TExpressionSolver.Solve(const Expr: string; out
+  ExprResult: string): boolean;
+begin
+  Result:=Solve(Expr,1,length(Expr),ExprResult);
+end;
+
+function TExpressionSolver.Solve(const Src: string;
+  StartPos, EndPos: integer; out ExprResult: string): boolean;
+{ '' -> ''
+  true = nonzero, false = zero
+  defined(name)
+  sizeof(type)
+  unary operators: not, !
+  binary operators: = <> >= <= > < and or xor shl shr
+  round brackets ()
+}
+var
+  AtomStart: LongInt;
+  SrcPos: LongInt;
+
+  function AtomIs(const s: shortstring): boolean;
+  var
+    len: Integer;
+    i: Integer;
+  begin
+    len:=length(s);
+    if (len<>SrcPos-AtomStart) then exit(false);
+    if SrcPos>EndPos then exit(false);
+    for i:=1 to len do
+      if Src[AtomStart+i-1]<>s[i] then exit(false);
+    Result:=true;
+  end;
+
+begin
+  if StartPos>=EndPos then begin
+    ExprResult:='';
+    exit(true);
+  end;
+  SrcPos:=StartPos;
+  AtomStart:=SrcPos;
+  //ReadNextCAtom(Source,SrcPos,AtomStart);
+  if AtomIs('!') then begin
+
+  end;
+end;
+
 initialization
   InternalInit;
 
diff --git a/components/codetools/h2pastool.pas b/components/codetools/h2pastool.pas
index edbd7e1edc..d107246284 100644
--- a/components/codetools/h2pastool.pas
+++ b/components/codetools/h2pastool.pas
@@ -1012,6 +1012,7 @@ var
   AtomStart: integer;
   BracketLvl: Integer;
   LastToken: TTokenType;
+  NeedBracket: Boolean;
 
   function AtomIs(const s: shortstring): boolean;
   var
@@ -1105,12 +1106,12 @@ begin
       end;
       if AtomIs('defined') then begin
         Add(ttValue);
-        // read   defined(name)
+        // read   defined(name)   or   defined name
         ReadRawNextCAtom(CCode,p,AtomStart);
-        if not AtomIs('(') then begin
-          ErrorExpectedButFound('(');
-          exit;
-        end;
+        if AtomIs('(') then
+          NeedBracket:=true
+        else
+          NeedBracket:=false;
         Add(ttBracketOpen);
         ReadRawNextCAtom(CCode,p,AtomStart);
         if (AtomStart>=EndPos) or (not IsIdentStartChar[CCode[AtomStart]])
@@ -1123,10 +1124,12 @@ begin
           Add(ttValue,'FPC')
         else
           Add(ttValue);
-        ReadRawNextCAtom(CCode,p,AtomStart);
-        if not AtomIs(')') then begin
-          ErrorExpectedButFound(')');
-          exit;
+        if NeedBracket then begin
+          ReadRawNextCAtom(CCode,p,AtomStart);
+          if not AtomIs(')') then begin
+            ErrorExpectedButFound(')');
+            exit;
+          end;
         end;
         Add(ttBracketClose);
       end else begin