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Re: [PATCH] handle invalid array index in warn_placement_new_too_small (PR 83058)

From: Jason Merrill <jason at redhat dot com>
To: Martin Sebor <msebor at gmail dot com>, Gcc Patch List <gcc-patches at gcc dot gnu dot org>
Date: Mon, 27 Nov 2017 17:11:22 -0500
Subject: Re: [PATCH] handle invalid array index in warn_placement_new_too_small (PR 83058)
Authentication-results: sourceware.org; auth=none
References: <42cfde95-0480-8781-0413-23f2de315735@gmail.com>

On 11/27/2017 02:24 PM, Martin Sebor wrote:

Bug 83058 - [6/7/8 Regression] ICE on C++ code with negative array
index: in warn_placement_new_too_small, at cp/init.c:2666, reports
an ICE for an invalid placement new expression with a negative
array index.

The ICE was caused by calling tree_to_uhwi (nelts) without first
checking to make sure nelts is fits in an unsigned HOST_WIDE_INT.

While testing the code for similar boundary conditions I also found
a few other cases that the code doesn't handle entirely correctly.

To avoid the ICE the attached patch uses offset_int instead of
HOST_WIDE_INT to track offsets and sizes.  It also improves
the handling of the other edge cases.


OK.

Jason

References:
- [PATCH] handle invalid array index in warn_placement_new_too_small (PR 83058)
  - From: Martin Sebor

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