Hi!
The new warn_placement_new_too_small function blindly assumes that
if {DECL,TYPE}_SIZE_UNIT is non-NULL, then it must be INTEGER_CST
that fits into uhwi. That is not the case, it could be a VLA, etc.
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux,
ok for trunk?
OT, as I said in bugzilla, I see very questionable code in that function
too, no idea what Martin meant with that:
while (TREE_CODE (oper) == COMPONENT_REF)
{
tree op0 = oper;
while (TREE_CODE (op0 = TREE_OPERAND (op0, 0)) == COMPONENT_REF);
if (TREE_CODE (op0) == VAR_DECL)
var_decl = op0;
oper = TREE_OPERAND (oper, 1);
}
TREE_OPERAND (oper, 1) of a COMPONENT_REF should be always a FIELD_DECL,
so this will never loop. Did you mean to use if instead of while, something
different?
2016-04-01 Jakub Jelinek <ja...@redhat.com>
Marek Polacek <pola...@redhat.com>
PR c++/70488
* init.c (warn_placement_new_too_small): Test whether
DECL_SIZE_UNIT or TYPE_SIZE_UNIT are integers that fit into uhwi.
* g++.dg/init/new47.C: New test.
--- gcc/cp/init.c.jj 2016-03-31 10:55:58.000000000 +0200
+++ gcc/cp/init.c 2016-04-01 14:23:25.977800499 +0200
@@ -2430,7 +2430,8 @@ warn_placement_new_too_small (tree type,
though the size of a member of a union may be viewed as extending
to the end of the union itself (it is by __builtin_object_size). */
if ((TREE_CODE (oper) == VAR_DECL || use_obj_size)
- && DECL_SIZE_UNIT (oper))
+ && DECL_SIZE_UNIT (oper)
+ && tree_fits_uhwi_p (DECL_SIZE_UNIT (oper)))
{
/* Use the size of the entire array object when the expression
refers to a variable or its size depends on an expression
@@ -2438,7 +2439,8 @@ warn_placement_new_too_small (tree type,
bytes_avail = tree_to_uhwi (DECL_SIZE_UNIT (oper));
exact_size = !use_obj_size;
}
- else if (TYPE_SIZE_UNIT (TREE_TYPE (oper)))
+ else if (TYPE_SIZE_UNIT (TREE_TYPE (oper))
+ && tree_fits_uhwi_p (TYPE_SIZE_UNIT (TREE_TYPE (oper))))
{
/* Use the size of the type of the destination buffer object
as the optimistic estimate of the available space in it. */
--- gcc/testsuite/g++.dg/init/new47.C.jj 2016-04-01 14:36:20.516355623
+0200
+++ gcc/testsuite/g++.dg/init/new47.C 2016-04-01 14:36:34.162171718 +0200
@@ -0,0 +1,19 @@
+// PR c++/70448
+// { dg-do compile }
+// { dg-options "-Wall" }
+
+typedef __typeof__ (sizeof 0) size_t;
+void *operator new (size_t, void *p) { return p; }
+void *operator new[] (size_t, void *p) { return p; }
+struct S { size_t s; };
+void bar (S *);
+
+void
+foo (unsigned int s)
+{
+ char t[sizeof (S) + s];
+ S *f = new (t) S;
+ bar (f);
+ f = new (t) S[1];
+ bar (f);
+}
Jakub
