GCC 4.5: "nonconstant array index in initializer" error
Joseph S. Myers
joseph@codesourcery.com
Sat Apr 25 23:37:00 GMT 2009
On Sat, 25 Apr 2009, Denis Onischenko wrote:
> Thanks for the patch.
>
> There are another error while building linux kernel with GCC 4.5.0
> revision 146771.
>
> The minimal code for reproducing the error looks like:
>
> extern unsigned int __invalid_size_argument;
> #define TYPECHECK(t) ( sizeof(t) == sizeof(t[1]) ? sizeof(t) :
> __invalid_size_argument )
>
> enum {
> ENUM_VALUE_NAME = TYPECHECK(int),
> };
I have applied this further patch to make this case also a
pedwarn-if-pedantic. Bootstrapped with no regressions on
x86_64-unknown-linux-gnu.
2009-04-25 Joseph Myers <joseph@codesourcery.com>
* c-decl.c (build_enumerator): Allow values folding to integer
constants but not integer constant expressions with a pedwarn if
pedantic.
testsuite:
2009-04-25 Joseph Myers <joseph@codesourcery.com>
* gcc.dg/enum-const-1.c, gcc.dg/enum-const-2.c,
gcc.dg/enum-const-3.c: New tests.
* gcc.dg/gnu89-const-expr-1.c, gcc.dg/gnu99-const-expr-1.c: Use
-pedantic-errors. Update expected diagnostics.
Index: gcc/testsuite/gcc.dg/enum-const-3.c
===================================================================
--- gcc/testsuite/gcc.dg/enum-const-3.c (revision 0)
+++ gcc/testsuite/gcc.dg/enum-const-3.c (revision 0)
@@ -0,0 +1,8 @@
+/* Test for enumeration constants not integer constant expressions but
+ folding to integer constants (used in Linux kernel,
+ <http://gcc.gnu.org/ml/gcc/2009-04/msg00677.html>). */
+/* { dg-do compile } */
+/* { dg-options "-pedantic-errors" } */
+
+extern int i;
+enum e { E = (1 ? 1 : i) }; /* { dg-error "not an integer constant expression" } */
Index: gcc/testsuite/gcc.dg/enum-const-1.c
===================================================================
--- gcc/testsuite/gcc.dg/enum-const-1.c (revision 0)
+++ gcc/testsuite/gcc.dg/enum-const-1.c (revision 0)
@@ -0,0 +1,8 @@
+/* Test for enumeration constants not integer constant expressions but
+ folding to integer constants (used in Linux kernel,
+ <http://gcc.gnu.org/ml/gcc/2009-04/msg00677.html>). */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+extern int i;
+enum e { E = (1 ? 1 : i) };
Index: gcc/testsuite/gcc.dg/gnu89-const-expr-1.c
===================================================================
--- gcc/testsuite/gcc.dg/gnu89-const-expr-1.c (revision 146747)
+++ gcc/testsuite/gcc.dg/gnu89-const-expr-1.c (working copy)
@@ -1,7 +1,7 @@
/* Test for constant expressions: GNU extensions. */
/* Origin: Joseph Myers <joseph@codesourcery.com> */
/* { dg-do compile } */
-/* { dg-options "-std=gnu89" } */
+/* { dg-options "-std=gnu89 -pedantic-errors" } */
int n;
@@ -9,39 +9,48 @@ void
f (void)
{
int i = 0;
- int a[n];
+ int a[n]; /* { dg-error "ISO C90 forbids variable length array" } */
enum e1 {
/* Integer constant expressions may not contain statement
expressions (not a permitted operand). */
- E1 = (1 ? 0 : ({ 0; })), /* { dg-error "constant" } */
+ E1 = (1 ? 0 : ({ 0; })), /* { dg-error "constant expression" } */
+ /* { dg-error "ISO C forbids braced-groups" "ISO" { target *-*-* } 16 } */
/* Real and imaginary parts act like other arithmetic
operators. */
- E2 = __real__ (1 ? 0 : i++), /* { dg-error "constant" } */
+ E2 = __real__ (1 ? 0 : i++), /* { dg-error "constant expression" } */
E3 = __real__ 0,
E4 = __imag__ (1 ? 0 : i++), /* { dg-error "constant" } */
E5 = __imag__ 0,
/* __alignof__ always constant. */
- E6 = __alignof__ (int[n]),
+ E6 = __alignof__ (int[n]), /* { dg-error "ISO C90 forbids variable length array" } */
E7 = __alignof__ (a),
/* __extension__ ignored for constant expression purposes. */
- E8 = __extension__ (1 ? 0 : i++), /* { dg-error "constant" } */
+ E8 = __extension__ (1 ? 0 : i++), /* { dg-error "constant expression" } */
E9 = __extension__ 0,
/* Conditional expressions with omitted arguments act like the
standard type. */
- E10 = (1 ? : i++), /* { dg-error "constant" } */
- E11 = (1 ? : 0)
+ E10 = (1 ? : i++), /* { dg-error "constant expression" } */
+ /* { dg-error "ISO C forbids omitting" "ISO" { target *-*-* } 32 } */
+ E11 = (1 ? : 0) /* { dg-error "ISO C forbids omitting" } */
};
enum e2 {
/* Complex integer constants may be cast directly to integer
types, but not after further arithmetic on them. */
- F1 = (int) (_Complex int) 2i, /* { dg-error "constant" } */
- F2 = (int) +2i, /* { dg-error "constant" } */
- F3 = (int) (1 + 2i), /* { dg-error "constant" } */
- F4 = (int) 2i
+ F1 = (int) (_Complex int) 2i, /* { dg-error "constant expression" } */
+ /* { dg-error "complex" "complex" { target *-*-* } 39 } */
+ /* { dg-error "imaginary" "imaginary" { target *-*-* } 39 } */
+ F2 = (int) +2i, /* { dg-error "constant expression" } */
+ /* { dg-error "imaginary" "ISO" { target *-*-* } 42 } */
+ F3 = (int) (1 + 2i), /* { dg-error "constant expression" } */
+ /* { dg-error "imaginary" "ISO" { target *-*-* } 44 } */
+ F4 = (int) 2i /* { dg-error "imaginary" } */
};
static double dr = __real__ (1.0 + 2.0i);
+ /* { dg-error "imaginary" "ISO" { target *-*-* } 48 } */
static double di = __imag__ (1.0 + 2.0i);
+ /* { dg-error "imaginary" "ISO" { target *-*-* } 50 } */
/* Statement expressions allowed in unevaluated subexpressions in
initializers in gnu99 but not gnu89. */
- static int j = (1 ? 0 : ({ 0; })); /* { dg-warning "constant expression" } */
+ static int j = (1 ? 0 : ({ 0; })); /* { dg-error "constant expression" } */
+ /* { dg-error "braced" "ISO" { target *-*-* } 54 } */
}
Index: gcc/testsuite/gcc.dg/gnu99-const-expr-1.c
===================================================================
--- gcc/testsuite/gcc.dg/gnu99-const-expr-1.c (revision 146747)
+++ gcc/testsuite/gcc.dg/gnu99-const-expr-1.c (working copy)
@@ -1,7 +1,7 @@
/* Test for constant expressions: GNU extensions. */
/* Origin: Joseph Myers <joseph@codesourcery.com> */
/* { dg-do compile } */
-/* { dg-options "-std=gnu99" } */
+/* { dg-options "-std=gnu99 -pedantic-errors" } */
int n;
@@ -13,10 +13,11 @@ f (void)
enum e1 {
/* Integer constant expressions may not contain statement
expressions (not a permitted operand). */
- E1 = (1 ? 0 : ({ 0; })), /* { dg-error "constant" } */
+ E1 = (1 ? 0 : ({ 0; })), /* { dg-error "constant expression" } */
+ /* { dg-error "ISO C forbids braced-groups" "ISO" { target *-*-* } 16 } */
/* Real and imaginary parts act like other arithmetic
operators. */
- E2 = __real__ (1 ? 0 : i++), /* { dg-error "constant" } */
+ E2 = __real__ (1 ? 0 : i++), /* { dg-error "constant expression" } */
E3 = __real__ 0,
E4 = __imag__ (1 ? 0 : i++), /* { dg-error "constant" } */
E5 = __imag__ 0,
@@ -24,24 +25,32 @@ f (void)
E6 = __alignof__ (int[n]),
E7 = __alignof__ (a),
/* __extension__ ignored for constant expression purposes. */
- E8 = __extension__ (1 ? 0 : i++), /* { dg-error "constant" } */
+ E8 = __extension__ (1 ? 0 : i++), /* { dg-error "constant expression" } */
E9 = __extension__ 0,
/* Conditional expressions with omitted arguments act like the
standard type. */
- E10 = (1 ? : i++), /* { dg-error "constant" } */
- E11 = (1 ? : 0)
+ E10 = (1 ? : i++), /* { dg-error "constant expression" } */
+ /* { dg-error "ISO C forbids omitting" "ISO" { target *-*-* } 32 } */
+ E11 = (1 ? : 0) /* { dg-error "ISO C forbids omitting" } */
};
enum e2 {
/* Complex integer constants may be cast directly to integer
types, but not after further arithmetic on them. */
- F1 = (int) (_Complex int) 2i, /* { dg-error "constant" } */
- F2 = (int) +2i, /* { dg-error "constant" } */
- F3 = (int) (1 + 2i), /* { dg-error "constant" } */
- F4 = (int) 2i
+ F1 = (int) (_Complex int) 2i, /* { dg-error "constant expression" } */
+ /* { dg-error "complex" "complex" { target *-*-* } 39 } */
+ /* { dg-error "imaginary" "imaginary" { target *-*-* } 39 } */
+ F2 = (int) +2i, /* { dg-error "constant expression" } */
+ /* { dg-error "imaginary" "ISO" { target *-*-* } 42 } */
+ F3 = (int) (1 + 2i), /* { dg-error "constant expression" } */
+ /* { dg-error "imaginary" "ISO" { target *-*-* } 44 } */
+ F4 = (int) 2i /* { dg-error "imaginary" } */
};
static double dr = __real__ (1.0 + 2.0i);
+ /* { dg-error "imaginary" "ISO" { target *-*-* } 48 } */
static double di = __imag__ (1.0 + 2.0i);
+ /* { dg-error "imaginary" "ISO" { target *-*-* } 50 } */
/* Statement expressions allowed in unevaluated subexpressions in
initializers in gnu99 but not gnu89. */
static int j = (1 ? 0 : ({ 0; }));
+ /* { dg-error "braced" "ISO" { target *-*-* } 54 } */
}
Index: gcc/testsuite/gcc.dg/enum-const-2.c
===================================================================
--- gcc/testsuite/gcc.dg/enum-const-2.c (revision 0)
+++ gcc/testsuite/gcc.dg/enum-const-2.c (revision 0)
@@ -0,0 +1,8 @@
+/* Test for enumeration constants not integer constant expressions but
+ folding to integer constants (used in Linux kernel,
+ <http://gcc.gnu.org/ml/gcc/2009-04/msg00677.html>). */
+/* { dg-do compile } */
+/* { dg-options "-pedantic" } */
+
+extern int i;
+enum e { E = (1 ? 1 : i) }; /* { dg-warning "not an integer constant expression" } */
Index: gcc/c-decl.c
===================================================================
--- gcc/c-decl.c (revision 146778)
+++ gcc/c-decl.c (working copy)
@@ -6077,16 +6077,32 @@ build_enumerator (struct c_enum_contents
undeclared identifier) - just ignore the value expression. */
if (value == error_mark_node)
value = 0;
- else if (!INTEGRAL_TYPE_P (TREE_TYPE (value))
- || TREE_CODE (value) != INTEGER_CST)
+ else if (!INTEGRAL_TYPE_P (TREE_TYPE (value)))
{
error ("enumerator value for %qE is not an integer constant", name);
value = 0;
}
else
{
- value = default_conversion (value);
- constant_expression_warning (value);
+ if (TREE_CODE (value) != INTEGER_CST)
+ {
+ value = c_fully_fold (value, false, NULL);
+ if (TREE_CODE (value) == INTEGER_CST)
+ pedwarn (value_loc, OPT_pedantic,
+ "enumerator value for %qE is not an integer "
+ "constant expression", name);
+ }
+ if (TREE_CODE (value) != INTEGER_CST)
+ {
+ error ("enumerator value for %qE is not an integer constant",
+ name);
+ value = 0;
+ }
+ else
+ {
+ value = default_conversion (value);
+ constant_expression_warning (value);
+ }
}
}
--
Joseph S. Myers
joseph@codesourcery.com
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