Bug 105087

Summary: Some Math.pow test262 tests fail with MinGW-w64
Product: WebKit Reporter: Jonathan Liu <net147>
Component: JavaScriptCoreAssignee: Nobody <webkit-unassigned>
Status: RESOLVED FIXED    
Severity: Normal CC: barraclough, hausmann, kai.koehne, mhahnenberg, sam, webkit.review.bot
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
Bug Depends on:    
Bug Blocks: 103747    
Attachments:
Description Flags
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Jonathan Liu
Reported 2012-12-15 05:44:35 PST
The following test262 tests fail with the latest MinGW-w64 runtime: -S15.8.2.13_A14 Checking if Math.pow(x,y) equals to +Infinity, where x is -Infinity and y>0 -S15.8.2.13_A16 Checking if Math.pow(x,y) equals to +0, where x is -Infinity and y<0 -S15.8.2.13_A20 Checking if Math.pow(x,y) equals to +0, where x is -0 and y>0 and y is NOT an odd integer -S15.8.2.13_A22 Checking if Math.pow(x,y) equals to +Infinity, where x is -0 and y<0 and y is NOT an odd integer This is due to different behavior of pow() with the MinGW-w64 runtime compared with other C runtimes. I have already fixed this issue in Google V8 (http://code.google.com/p/v8/source/browse/trunk/src/assembler.cc?spec=svn13185&r=13185#1397).
Attachments
Patch (1.81 KB, patch)
2012-12-15 05:51 PST, Jonathan Liu 		no flags
DetailsFormatted DiffDiff
Patch (1.81 KB, patch)
2012-12-15 05:55 PST, Jonathan Liu 		no flags
DetailsFormatted DiffDiff
Patch (1.82 KB, patch)
2012-12-15 06:00 PST, Jonathan Liu 		no flags
DetailsFormatted DiffDiff
Patch (1.81 KB, patch)
2012-12-17 02:13 PST, Jonathan Liu 		no flags
DetailsFormatted DiffDiff
Show Obsolete (3) View All Add attachment proposed patch, testcase, etc.
Jonathan Liu
Comment 1 2012-12-15 05:51:21 PST
Created attachment 179590 [details] Patch
WebKit Review Bot
Comment 2 2012-12-15 05:53:40 PST
Attachment 179590 [details] did not pass style-queue: Failed to run "['Tools/Scripts/check-webkit-style', '--diff-files', u'Source/JavaScriptCore/ChangeLog', u'Source..." exit_code: 1 Source/JavaScriptCore/runtime/MathObject.cpp:236: Should have only a single space after a punctuation in a comment. [whitespace/comments] [5] Source/JavaScriptCore/runtime/MathObject.cpp:245: y_int is incorrectly named. Don't use underscores in your identifier names. [readability/naming/underscores] [4] Source/JavaScriptCore/runtime/MathObject.cpp:246: More than one command on the same line in if [whitespace/parens] [4] Total errors found: 3 in 2 files If any of these errors are false positives, please file a bug against check-webkit-style.
Jonathan Liu
Comment 3 2012-12-15 05:55:44 PST
Created attachment 179592 [details] Patch
WebKit Review Bot
Comment 4 2012-12-15 05:58:02 PST
Attachment 179592 [details] did not pass style-queue: Failed to run "['Tools/Scripts/check-webkit-style', '--diff-files', u'Source/JavaScriptCore/ChangeLog', u'Source..." exit_code: 1 Source/JavaScriptCore/runtime/MathObject.cpp:236: Should have only a single space after a punctuation in a comment. [whitespace/comments] [5] Source/JavaScriptCore/runtime/MathObject.cpp:246: More than one command on the same line in if [whitespace/parens] [4] Total errors found: 2 in 2 files If any of these errors are false positives, please file a bug against check-webkit-style.
Jonathan Liu
Comment 5 2012-12-15 06:00:05 PST
Created attachment 179593 [details] Patch
Simon Hausmann
Comment 6 2012-12-17 01:42:52 PST
Comment on attachment 179593 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=179593&action=review > Source/JavaScriptCore/runtime/MathObject.cpp:235 > +#ifdef __MINGW64_VERSION_MAJOR I think this should be #if COMPILER(MINGW64) > Source/JavaScriptCore/runtime/MathObject.cpp:244 > + if ((x == 0.0 || isinf(x)) && isfinite(y)) { > + double f; > + if (modf(y, &f) != 0.0) > + return ((x == 0.0) ^ (y > 0.0)) ? std::numeric_limits<double>::infinity() : 0.0; > + } > + > + if (x == 2.0) { Isn't it dangerous to compare doubles to constants like that? Shouldn't it be done as a range comparison using a epsilon?
Jonathan Liu
Comment 7 2012-12-17 02:13:05 PST
Created attachment 179707 [details] Patch
Jonathan Liu
Comment 8 2012-12-17 02:19:56 PST
The special cases apply only to exact values so it is fine in my opinion.
Simon Hausmann
Comment 9 2012-12-17 03:29:10 PST
Upstream "discussion" about the behavioral difference: http://comments.gmane.org/gmane.comp.gnu.mingw.w64.general/4658
WebKit Review Bot
Comment 10 2012-12-17 03:51:02 PST
Comment on attachment 179707 [details] Patch Clearing flags on attachment: 179707 Committed r137895: <http://trac.webkit.org/changeset/137895>
WebKit Review Bot
Comment 11 2012-12-17 03:51:07 PST
All reviewed patches have been landed. Closing bug.
Sam Weinig
Comment 12 2012-12-27 20:35:54 PST
I don't think this is the best way to do this. The preferred method is to add a function to MathExtras.h which implements pow correctly and call that, so that we don't litter the code with #ifdefs.
Jonathan Liu
Comment 13 2012-12-29 18:58:51 PST
(In reply to comment #12) > I don't think this is the best way to do this. The preferred method is to add a function to MathExtras.h which implements pow correctly and call that, so that we don't litter the code with #ifdefs. According to the bug life cycle, this bug is fixed. Feel free to commit such a change separately.
Simon Hausmann
Comment 14 2013-01-02 08:15:36 PST
I've filed bug #105925 to address Sam's (valid) comment.
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