On Tue, Apr 12, 2011 at 07:13:51PM -0400, Jason Merrill wrote:
> On 04/12/2011 01:06 PM, Jakub Jelinek wrote:
> >+ : (unsigned)TREE_STRING_LENGTH (ary)
> >+ * (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (ary)))
> >+ / TYPE_PRECISION (char_type_node)));
>
> Don't you mean / instead of * here?
You're right, thanks for catching it. I've added a testcase
for the out of bounds case too.
> Let's also calculate the size
> of the element once rather than here and again later.
Like this? Bootstrapped/regtested on x86_64-linux and i686-linux:
2011-04-13 Jakub Jelinek <ja...@redhat.com>
PR c++/48570
* semantics.c (cxx_eval_array_reference): Handle reading from
wchar_t, char16_t and char32_t STRING_CST.
* g++.dg/cpp0x/constexpr-wstring1.C: New test.
* g++.dg/cpp0x/constexpr-wstring2.C: New test.
--- gcc/cp/semantics.c.jj 2011-04-12 19:43:49.433483082 +0200
+++ gcc/cp/semantics.c 2011-04-13 08:25:07.904796653 +0200
@@ -6279,7 +6279,7 @@ cxx_eval_array_reference (const constexp
non_constant_p);
tree index, oldidx;
HOST_WIDE_INT i;
- unsigned len;
+ unsigned len, elem_nchars = 1;
if (*non_constant_p)
return t;
oldidx = TREE_OPERAND (t, 1);
@@ -6291,9 +6291,14 @@ cxx_eval_array_reference (const constexp
return t;
else if (addr)
return build4 (ARRAY_REF, TREE_TYPE (t), ary, index, NULL, NULL);
- len = (TREE_CODE (ary) == CONSTRUCTOR
- ? CONSTRUCTOR_NELTS (ary)
- : (unsigned)TREE_STRING_LENGTH (ary));
+ if (TREE_CODE (ary) == CONSTRUCTOR)
+ len = CONSTRUCTOR_NELTS (ary);
+ else
+ {
+ elem_nchars = (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (ary)))
+ / TYPE_PRECISION (char_type_node));
+ len = (unsigned) TREE_STRING_LENGTH (ary) / elem_nchars;
+ }
if (compare_tree_int (index, len) >= 0)
{
if (!allow_non_constant)
@@ -6304,9 +6309,16 @@ cxx_eval_array_reference (const constexp
i = tree_low_cst (index, 0);
if (TREE_CODE (ary) == CONSTRUCTOR)
return VEC_index (constructor_elt, CONSTRUCTOR_ELTS (ary), i)->value;
- else
+ else if (elem_nchars == 1)
return build_int_cst (cv_unqualified (TREE_TYPE (TREE_TYPE (ary))),
TREE_STRING_POINTER (ary)[i]);
+ else
+ {
+ tree type = cv_unqualified (TREE_TYPE (TREE_TYPE (ary)));
+ return native_interpret_expr (type, (const unsigned char *)
+ TREE_STRING_POINTER (ary)
+ + i * elem_nchars, elem_nchars);
+ }
/* Don't VERIFY_CONSTANT here. */
}
--- gcc/testsuite/g++.dg/cpp0x/constexpr-wstring1.C.jj 2011-04-13
08:21:23.079513403 +0200
+++ gcc/testsuite/g++.dg/cpp0x/constexpr-wstring1.C 2011-04-13
08:21:23.079513403 +0200
@@ -0,0 +1,34 @@
+// PR c++/48570
+// { dg-do run }
+// { dg-options "-std=c++0x" }
+
+extern "C" void abort ();
+constexpr wchar_t foo (int i) { return L"0123"[i]; }
+constexpr char16_t bar (int i) { return u"0123"[i]; }
+constexpr char32_t baz (int i) { return U"0123"[i]; }
+const wchar_t foo0 = foo (0);
+const wchar_t foo1 = foo (1);
+const wchar_t foo2 = foo (2);
+const wchar_t foo3 = foo (3);
+const wchar_t foo4 = foo (4);
+const char16_t bar0 = bar (0);
+const char16_t bar1 = bar (1);
+const char16_t bar2 = bar (2);
+const char16_t bar3 = bar (3);
+const char16_t bar4 = bar (4);
+const char32_t baz0 = baz (0);
+const char32_t baz1 = baz (1);
+const char32_t baz2 = baz (2);
+const char32_t baz3 = baz (3);
+const char32_t baz4 = baz (4);
+
+int
+main ()
+{
+ if (foo0 != L'0' || foo1 != L'1' || foo2 != L'2' || foo3 != L'3' || foo4 !=
L'\0')
+ abort ();
+ if (bar0 != u'0' || bar1 != u'1' || bar2 != u'2' || bar3 != u'3' || bar4 !=
u'\0')
+ abort ();
+ if (baz0 != U'0' || baz1 != U'1' || baz2 != U'2' || baz3 != U'3' || baz4 !=
U'\0')
+ abort ();
+}
--- gcc/testsuite/g++.dg/cpp0x/constexpr-wstring2.C.jj 2011-04-13
08:26:01.158764728 +0200
+++ gcc/testsuite/g++.dg/cpp0x/constexpr-wstring2.C 2011-04-13
08:29:31.321808236 +0200
@@ -0,0 +1,7 @@
+// PR c++/48570
+// { dg-do compile }
+// { dg-options -std=c++0x }
+
+constexpr wchar_t c1 = L"hi"[3]; // { dg-error "out of bound" }
+constexpr char16_t c2 = u"hi"[3]; // { dg-error "out of bound" }
+constexpr char32_t c3 = U"hi"[3]; // { dg-error "out of bound" }
Jakub
