Bug 223614 - wtf/text/IntegerToStringConversion.h:54:104: runtime error: negation of -2147483648 cannot be represented in type 'int'; cast to an unsigned type to negate this value to itself
Summary: wtf/text/IntegerToStringConversion.h:54:104: runtime error: negation of -2147...
Status: RESOLVED FIXED
Alias: None
Product: WebKit
Classification: Unclassified
Component: Web Template Framework (show other bugs)
Version: WebKit Nightly Build
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Chris Dumez
URL:
Keywords: InRadar
Depends on:
Blocks:
 
Reported: 2021-03-22 17:16 PDT by Chris Dumez
Modified: 2021-03-23 09:55 PDT (History)
8 users (show)

See Also:

Attachments
Patch (3.99 KB, patch)
2021-03-22 17:21 PDT, Chris Dumez 		no flags Details | Formatted Diff | Diff
Patch (4.99 KB, patch)
2021-03-22 17:39 PDT, Chris Dumez 		no flags Details | Formatted Diff | Diff
Patch (4.95 KB, patch)
2021-03-23 08:32 PDT, Chris Dumez 		no flags Details | Formatted Diff | Diff
Show Obsolete (2) View All Add an attachment (proposed patch, testcase, etc.)

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Description Chris Dumez 2021-03-22 17:16:10 PDT 
numberToStringSigned() relies on undefined behavior and may return inaccurate results with inputs such as INT_MIN.
Comment 1 Chris Dumez 2021-03-22 17:21:06 PDT 
Created attachment 423967 [details]
Patch
Comment 2 Chris Dumez 2021-03-22 17:39:38 PDT 
Created attachment 423972 [details]
Patch
Comment 3 Chris Dumez 2021-03-23 08:32:06 PDT 
Created attachment 424020 [details]
Patch
Comment 4 Darin Adler 2021-03-23 09:01:34 PDT 
Comment on attachment 424020 [details]
Patch

I understand how this quiets the undefined behavior sanitizer, but I am sort of surprised that this actually avoids undefined behavior. I am surprised that the unary minus operation is defined so usefully on unsigned types.
Comment 5 Chris Dumez 2021-03-23 09:04:53 PDT 
(In reply to Darin Adler from comment #4)
> Comment on attachment 424020 [details]
> Patch
> 
> I understand how this quiets the undefined behavior sanitizer, but I am sort
> of surprised that this actually avoids undefined behavior. I am surprised
> that the unary minus operation is defined so usefully on unsigned types.

I followed the advice from UBSan: "cast to an unsigned type to negate this value to itself".
Comment 6 EWS 2021-03-23 09:54:11 PDT 
Committed r274878: <https://commits.webkit.org/r274878>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 424020 [details].
Comment 7 Radar WebKit Bug Importer 2021-03-23 09:55:20 PDT 
<rdar://problem/75742118>