digitalmars.D.bugs - [Issue 9957] New: [2.061 -> 2.062] Taking pointer of enum float array gives some garbage
- d-bugmail puremagic.com (39/42) Apr 18 2013 http://d.puremagic.com/issues/show_bug.cgi?id=9957
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http://d.puremagic.com/issues/show_bug.cgi?id=9957
Summary: [2.061 -> 2.062] Taking pointer of enum float array
gives some garbage
Product: D
Version: D2
Platform: All
OS/Version: Mac OS X
Status: NEW
Severity: regression
Priority: P2
Component: DMD
AssignedTo: nobody puremagic.com
ReportedBy: stdin kraybit.com
import std.stdio;
void main()
{
enum float[3][1] A = [[1.0, 2.0, 3.0]];
auto a = A[0].ptr;
writeln(a[0], " should be ", A[0][0]);
writeln(a[1], " should be ", A[0][1]);
writeln(a[2], " should be ", A[0][2]);
}
————
rdmd -m32 test.d
1 should be 1
1.76941e-40 should be 2
-1.98565 should be 3
rdmd -m64 test.d
1 should be 1
1.4013e-45 should be 2
4.33594e+15 should be 3
_
————
Example output above. Changes every run.
Worked in 2.061. Don't know if it's supposed to work, but if not, should at
least throw an error?
MacOS 10.8.3
DMD 2.062
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Apr 18 2013
d-bugmail puremagic.com http://d.puremagic.com/issues/show_bug.cgi?id=9957 I don't think this should compile. It's like writing auto p = &5; -- taking the address of a manifest constant doesn't make sense. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Apr 22 2013
http://d.puremagic.com/issues/show_bug.cgi?id=9957 This is a regression caused by fixing bug 8913.I don't think this should compile. It's like writing auto p = &5; -- taking the address of a manifest constant doesn't make sense.I think it should work. Manifest constant with array value will create array literal, so: auto a = A[0].ptr; will be optimized to: auto a = [1.0, 2.0, 3.0].ptr; By fixing bug 8913, accessing sarr.ptr is now lowered to &sarr[0]. With this, above code is also lowered to: auto a = &[1.0, 2.0, 3.0][0]; Then currently it is optimized to: auto a = &1.0; I think that the root cause of this bug is here. Essentially optimizer should keep lvalue-ness of expressions, but it is accidentally disappeared in the last optimization. It is incorrect. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Apr 23 2013
http://d.puremagic.com/issues/show_bug.cgi?id=9957
Kenji Hara <k.hara.pg gmail.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |pull, wrong-code
OS/Version|Mac OS X |All
https://github.com/D-Programming-Language/dmd/pull/1922
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Apr 23 2013
http://d.puremagic.com/issues/show_bug.cgi?id=9957This is a regression caused by fixing bug 8913.I think that's not valid. That isn't A[0].ptr It's A[0].dup.ptr. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------I don't think this should compile. It's like writing auto p = &5; -- taking the address of a manifest constant doesn't make sense.I think it should work. Manifest constant with array value will create array literal, so: auto a = A[0].ptr; will be optimized to: auto a = [1.0, 2.0, 3.0].ptr;
Apr 23 2013
http://d.puremagic.com/issues/show_bug.cgi?id=9957Hmm... Sure, in this case the array literal `[1.0, 2.0, 3.0]` has a _static array type_ float[3]. So getting its memory address is not well defined in current D language spec. I'd like to hear Walter's opinion. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------I think it should work. Manifest constant with array value will create array literal, so: auto a = A[0].ptr; will be optimized to: auto a = [1.0, 2.0, 3.0].ptr;I think that's not valid. That isn't A[0].ptr It's A[0].dup.ptr.
Apr 23 2013
http://d.puremagic.com/issues/show_bug.cgi?id=9957
Walter Bright <bugzilla digitalmars.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |bugzilla digitalmars.com
10:41:29 PDT ---
I agree with Don. Enums do not have an address (even if under the hood they
do). Users should use 'const' or 'immutable' if they need it to have an
address.
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Apr 23 2013
http://d.puremagic.com/issues/show_bug.cgi?id=9957I agree with Don. Enums do not have an address (even if under the hood they do). Users should use 'const' or 'immutable' if they need it to have an address.OK. It's not bad design. But implementing it is not so easy. Because 1. Current dmd does not have such information internally. CTFE engine now uses ownedByCtfe flag, but using it in semantic analysis is not intended. 2. It is not well designed enough. For example: enum float[] A = [1.0, 2.0, 3.0]; auto a = A.ptr; //? In this case, the elements of A would be allocated on the runtime heap, or "not addressable compile time memory"? Currently it operates as the former, but it should be prohibited? Anyway, doing all in 2.063 beta phase is difficult. Therefore I'd like to propose that: 1. We once fix this "regression" and make the OP code workable in 2.063, by merging my patch. 2. Later define the concept well and implement it. How about? -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Apr 23 2013
http://d.puremagic.com/issues/show_bug.cgi?id=9957I think it should be prohibited. In fact, the problem starts here:I agree with Don. Enums do not have an address (even if under the hood they do). Users should use 'const' or 'immutable' if they need it to have an address.OK. It's not bad design. But implementing it is not so easy. Because 1. Current dmd does not have such information internally. CTFE engine now uses ownedByCtfe flag, but using it in semantic analysis is not intended. 2. It is not well designed enough. For example: enum float[] A = [1.0, 2.0, 3.0]; auto a = A.ptr; //? In this case, the elements of A would be allocated on the runtime heap, or "not addressable compile time memory"? Currently it operates as the former, but it should be prohibited?enum float[] A = [1.0, 2.0, 3.0];I think, a bit controversially, that this line shouldn't compile. See bug 9953. An enum of a reference type doesn't make sense, since it implicitly requires an address.Anyway, doing all in 2.063 beta phase is difficult.I agree.Therefore I'd like to propose that: 1. We once fix this "regression" and make the OP code workable in 2.063, by merging my patch.That's probably the easiest thing to do. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Apr 24 2013
http://d.puremagic.com/issues/show_bug.cgi?id=9957
bearophile_hugs eml.cc changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |bearophile_hugs eml.cc
enum float[] A = [1.0, 2.0, 3.0];
I think, a bit controversially, that this line shouldn't compile.
See bug 9953.
An enum of a reference type doesn't make sense, since it implicitly requires an
address.
I kind of agree with this change, but it's a large change, so I think it should
be presented and discussed in the main D newsgroup.
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Apr 24 2013
http://d.puremagic.com/issues/show_bug.cgi?id=9957 Commits pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/dbc85a5d1f56cb74bc5bc16ac4fac3b133c1c07b fix Issue 9957 - Taking pointer of enum float array gives some garbage https://github.com/D-Programming-Language/dmd/commit/6c95d9b80eb1e597dda2d406baecafb90734f8c5 [REG2.062] Issue 9957 - Taking pointer of enum float array gives some garbage -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
May 25 2013
http://d.puremagic.com/issues/show_bug.cgi?id=9957 --- Commit pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/7518f83d0082e5cd339ef5d7c215f13a0287ad4b Do not include test case for issue 9957 It's not behavior that we guarantee. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
May 25 2013
http://d.puremagic.com/issues/show_bug.cgi?id=9957
Kenji Hara <k.hara.pg gmail.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |FIXED
---
In git head (and maybe in 2.063 release) the codegen bug has been fixed. So
I'll mark this as "resolved fixed".
But, taking address of the part of enum value is not guaranteed behavior in the
language spec. It would be disallowed in the future release. Do not rely on the
current behavior.
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May 25 2013
http://d.puremagic.com/issues/show_bug.cgi?id=9957 Commit pushed to 2.063 at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/95032fff948cbdbb63c31c7d9f19b39fe5117763 [REG2.062] Issue 9957 - Taking pointer of enum float array gives some garbage -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
May 27 2013