Re: [PATCH 0/3] yacc: compute the best type for the state number

[Akim Demaille]

> Le 5 oct. 2019 à 09:28, Akim Demaille <address@hidden> a écrit :
> 
> I can't wait: these errors are blocking from me from pushing other changes 
> that I was about to send.

With the appended commits, the CI is green again, and I was able to push my 
other changes.

commit 4246cd81df3101b1abef3f5914f6b3fa7d1b44de
Author: Akim Demaille <address@hidden>
Date:   Sat Oct 5 17:28:51 2019 +0200

    tests: avoid a GCC 4.8 warning
    
    GCC 4.8 reports:
    
        input.y:57:33: error: conversion to 'int' from 'long unsigned int'
                              may alter its value [-Werror=conversion]
           int input_elts = sizeof input / sizeof input[0];
                                         ^
    
    * tests/local.at (AT_YYLEX_DEFINE(c)): Add a cast (sorry, Paul!).

diff --git a/tests/local.at b/tests/local.at
index 17759b2f..579b85c3 100644
--- a/tests/local.at
+++ b/tests/local.at
@@ -558,7 +558,7 @@ static
   static int toknum = 0;
   int res;
   ]AT_USE_LEX_ARGS[
-  int input_elts = sizeof input / sizeof input[0];
+  int input_elts = (int) (sizeof input / sizeof input[0]);
   (void) input_elts;
   assert (0 <= toknum && toknum < input_elts);
   res = input[toknum++];







commit 5973d763c0867924830fa90f6560078f745d45a7
Author: Akim Demaille <address@hidden>
Date:   Sat Oct 5 17:35:40 2019 +0200

    yacc.c: work around warnings from Clang++ 3.3 and 3.4
    
    When we run the test suite with these C++ compilers to compile C code,
    we get:
    
        239. synclines.at:440: testing syncline escapes: yacc.c ...
        ../../tests/synclines.at:440: $CC $CFLAGS $CPPFLAGS \"\\\"\".c -o 
\"\\\"\" ||
                  exit 77
        stderr:
        stdout:
        ../../tests/synclines.at:440: COLUMNS=1000; export COLUMNS;  bison 
--color=no -fno-caret  -o \"\\\"\".c \"\\\"\".y
        ../../tests/synclines.at:440: $CC $CFLAGS $CPPFLAGS  $LDFLAGS -o 
\"\\\"\" \"\\\"\".c $LIBS
        stderr:
        "\"".c:1102:41: error: implicit conversion loses integer precision: 
'long' to 'int' [-Werror,-Wshorten-64-to-32]
              YYPTRDIFF_T yysize = yyssp - yyss + 1;
                          ~~~~~~   ~~~~~~~~~~~~~^~~
        1 error generated.
    
        193. conflicts.at:545: testing parse.error=verbose and consistent 
errors: lr.type=canonical-lr parse.lac=full ...
        input.c:737:75: error: implicit conversion loses integer precision: 
'long' to 'int'
                               [-Werror,-Wshorten-64-to-32]
          YYPTRDIFF_T yysize_old = *yytop == yytop_empty ? 0 : *yytop - 
*yybottom + 1;
                      ~~~~~~~~~~                               
~~~~~~~~~~~~~~~~~~~^~~
        input.c:901:48: error: implicit conversion loses integer precision: 
'long' to 'int'
                               [-Werror,-Wshorten-64-to-32]
                    YYPTRDIFF_T yysize = yyesp - *yyes + 1;
                                ~~~~~~   ~~~~~~~~~~~~~~^~~
    
    * data/skeletons/yacc.c: Add more casts.

diff --git a/data/skeletons/yacc.c b/data/skeletons/yacc.c
index fdf4ba6d..e4705735 100644
--- a/data/skeletons/yacc.c
+++ b/data/skeletons/yacc.c
@@ -856,7 +856,8 @@ yy_lac_stack_realloc (YYPTRDIFF_T *yycapacity, YYPTRDIFF_T 
yyadd,
                       yy_state_num *yybottom_no_free,
                       yy_state_num **yytop, yy_state_num *yytop_empty)
 {
-  YYPTRDIFF_T yysize_old = *yytop == yytop_empty ? 0 : *yytop - *yybottom + 1;
+  YYPTRDIFF_T yysize_old =
+    *yytop == yytop_empty ? 0 : (YYPTRDIFF_T) (*yytop - *yybottom + 1);
   YYPTRDIFF_T yysize_new = yysize_old + yyadd;
   if (*yycapacity < yysize_new)
     {
@@ -1023,7 +1024,7 @@ yy_lac (yy_state_num *yyesa, yy_state_num **yyes,
         YYDPRINTF ((stderr, " R%d", yyrule - 1));
         if (yyesp != yyes_prev)
           {
-            YYPTRDIFF_T yysize = yyesp - *yyes + 1;
+            YYPTRDIFF_T yysize = (YYPTRDIFF_T) (yyesp - *yyes + 1);
             if (yylen < yysize)
               {
                 yyesp -= yylen;
@@ -1534,7 +1535,7 @@ yysetstate:
 #else
     {
       /* Get the current used size of the three stacks, in elements.  */
-      YYPTRDIFF_T yysize = yyssp - yyss + 1;
+      YYPTRDIFF_T yysize = (YYPTRDIFF_T) (yyssp - yyss + 1);
 
 # if defined yyoverflow
       {












commit 32e5a91a91bc034a3f596c056569c0eaa09ca7e1
Author: Akim Demaille <address@hidden>
Date:   Sat Oct 5 22:51:16 2019 +0200

    yacc.c: work around warnings from G++ 4.8
    
    input.c: In function 'int yyparse()':
    input.c: error: conversion to 'long int' from 'long unsigned int'
                    may change the sign of the result [-Werror=sign-conversion]
       yyes_capacity = sizeof yyesa / sizeof *yyes;
                                    ^
    cc1plus: all warnings being treated as errors
    
    * data/skeletons/yacc.c: here.

diff --git a/TODO b/TODO
index f0ec27da..d99954e0 100644
--- a/TODO
+++ b/TODO
@@ -128,6 +128,25 @@ Rename these guys as "diagnostics.*" (or "diagnose.*"), 
since that's the
 name they have in gcc, clang, etc.  Likewise for the complain_* series of
 functions.
 
+* Modernization
+Remove some casts made for old compilers, such as Clang++ 3.3 and 3.4 when
+compiling yacc.c code:
+
+    YYPTRDIFF_T yysize = (YYPTRDIFF_T) (yyssp - yyss + 1);
+
+    YYPTRDIFF_T yysize_old =
+      *yytop == yytop_empty ? 0 : (YYPTRDIFF_T) (*yytop - *yybottom + 1);
+
+    YYPTRDIFF_T yysize = (YYPTRDIFF_T) (yyesp - *yyes + 1);
+
+Or G++ 4.8
+
+    yyes_capacity = (YYPTRDIFF_T) (sizeof yyesa / sizeof *yyes);
+
+Or GCC 4.8
+
+    int input_elts = (int) (sizeof input / sizeof input[0]);
+
 * Completion
 Several features are not available in all the backends.
 
diff --git a/data/skeletons/yacc.c b/data/skeletons/yacc.c
index e4705735..abe20a5f 100644
--- a/data/skeletons/yacc.c
+++ b/data/skeletons/yacc.c
@@ -1154,10 +1154,10 @@ yytnamerr (char *yyres, const char *yystr)
     do_not_strip_quotes: ;
     }
 
-  if (! yyres)
+  if (yyres)
+    return (YYPTRDIFF_T) (yystpcpy (yyres, yystr) - yyres);
+  else
     return yystrlen (yystr);
-
-  return yystpcpy (yyres, yystr) - yyres;
 }
 # endif
 
@@ -1490,7 +1490,7 @@ b4_function_define([[yyparse]], [[int]], b4_parse_param)[
   yystacksize = YYINITDEPTH;]b4_lac_if([[
 
   yyes = yyesa;
-  yyes_capacity = sizeof yyesa / sizeof *yyes;
+  yyes_capacity = (YYPTRDIFF_T) (sizeof yyesa / sizeof *yyes);
   if (YYMAXDEPTH < yyes_capacity)
     yyes_capacity = YYMAXDEPTH;]])[