(skip_evaluation): New variable.

(&&, ||, ?:): Increment it in unevaluated subexpressions.
(/, %, integer_overflow): Suppress diagnostics if skip_evaluation != 0.
(yyerror): Clear skip_evaluation.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@9914 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/cexp.y b/gcc/cexp.y
index 3c924ae..6082fec 100644 (file)
--- a/gcc/cexp.y
+++ b/gcc/cexp.y
@@ -86,6 +86,10 @@ static jmp_buf parse_return_error;
 /* Nonzero means count most punctuation as part of a name.  */
 static int keyword_parsing = 0;
 
+/* Nonzero means do not evaluate this expression.
+   This is a count, since unevaluated expressions can nest.  */
+static int skip_evaluation;
+
 /* some external tables of character types */
 extern unsigned char is_idstart[], is_idchar[], is_hor_space[];
 
@@ -225,7 +229,8 @@ exp :       exp '*' exp
        |       exp '/' exp
                        { if ($3.value == 0)
                            {
-                             error ("division by zero in #if");
+                             if (!skip_evaluation)
+                               error ("division by zero in #if");
                              $3.value = 1;
                            }
                          $$.unsignedp = $1.unsignedp || $3.unsignedp;
@@ -240,7 +245,8 @@ exp :       exp '*' exp
        |       exp '%' exp
                        { if ($3.value == 0)
                            {
-                             error ("division by zero in #if");
+                             if (!skip_evaluation)
+                               error ("division by zero in #if");
                              $3.value = 1;
                            }
                          $$.unsignedp = $1.unsignedp || $3.unsignedp;
@@ -313,15 +319,26 @@ exp       :       exp '*' exp
        |       exp '|' exp
                        { $$.value = $1.value | $3.value;
                          $$.unsignedp = $1.unsignedp || $3.unsignedp; }
-       |       exp AND exp
-                       { $$.value = ($1.value && $3.value);
+       |       exp AND
+                       { skip_evaluation += !$1.value; }
+               exp
+                       { skip_evaluation -= !$1.value;
+                         $$.value = ($1.value && $4.value);
                          $$.unsignedp = 0; }
-       |       exp OR exp
-                       { $$.value = ($1.value || $3.value);
+       |       exp OR
+                       { skip_evaluation += !!$1.value; }
+               exp
+                       { skip_evaluation -= !!$1.value;
+                         $$.value = ($1.value || $4.value);
                          $$.unsignedp = 0; }
-       |       exp '?' exp ':' exp
-                       { $$.value = $1.value ? $3.value : $5.value;
-                         $$.unsignedp = $3.unsignedp || $5.unsignedp; }
+       |       exp '?'
+                       { skip_evaluation += !$1.value; }
+               exp ':'
+                       { skip_evaluation += !!$1.value - !$1.value; }
+               exp
+                       { skip_evaluation -= !!$1.value;
+                         $$.value = $1.value ? $4.value : $7.value;
+                         $$.unsignedp = $4.unsignedp || $7.unsignedp; }
        |       INT
                        { $$ = yylval.integer; }
        |       CHAR
@@ -865,13 +882,14 @@ yyerror (s)
      char *s;
 {
   error (s);
+  skip_evaluation = 0;
   longjmp (parse_return_error, 1);
 }
 
 static void
 integer_overflow ()
 {
-  if (pedantic)
+  if (!skip_evaluation && pedantic)
     pedwarn ("integer overflow in preprocessor expression");
 }