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digitalmars.D - Issue 7965 - Invalid outer function scope pointer in some cases

reply Denis Shelomovskij <verylonglogin.reg gmail.com> writes:
Just want to mention again that Issue 7965 is a really nasty wrong-code 
bug that is difficult to find unless you know about it.

I face this Issue in almost every my D program with non-trivial 
std.algorithm usage and I suppose I'm not alone.

If there is no plans to fix it in near future this _must_ be mentioned 
in std.algorithm page and in other places in docs because it's really 
possible to avoid it every time you use std.algorithm.

It's not a joke! Such things must be mentioned in docs or D is unusable 
for non-experienced D developers.

http://d.puremagic.com/issues/show_bug.cgi?id=7965

-- 
Денис В. Шеломовский
Denis V. Shelomovskij
Jun 16 2012
next sibling parent reply "Era Scarecrow" <rtcvb32 yahoo.com> writes:
On Saturday, 16 June 2012 at 20:16:52 UTC, Denis Shelomovskij 
wrote:
 Just want to mention again that Issue 7965 is a really nasty 
 wrong-code bug that is difficult to find unless you know about 
 it.

 I face this Issue in almost every my D program with non-trivial 
 std.algorithm usage and I suppose I'm not alone.

 If there is no plans to fix it in near future this _must_ be 
 mentioned in std.algorithm page and in other places in docs 
 because it's really possible to avoid it every time you use 
 std.algorithm.

 It's not a joke! Such things must be mentioned in docs or D is 
 unusable for non-experienced D developers.

 http://d.puremagic.com/issues/show_bug.cgi?id=7965

Looks to me like a frame pointer bug for the delegate (Or lack of it?)... Based on the setup, it should also be illegal to pass the struct outside of the scope it's in due to the delegate in the struct (Unless the variable(s) in question are static).
Jun 16 2012
parent reply Timon Gehr <timon.gehr gmx.ch> writes:
On 06/16/2012 11:19 PM, Era Scarecrow wrote:
 On Saturday, 16 June 2012 at 20:16:52 UTC, Denis Shelomovskij wrote:
 Just want to mention again that Issue 7965 is a really nasty
 wrong-code bug that is difficult to find unless you know about it.

 I face this Issue in almost every my D program with non-trivial
 std.algorithm usage and I suppose I'm not alone.

 If there is no plans to fix it in near future this _must_ be mentioned
 in std.algorithm page and in other places in docs because it's really
 possible to avoid it every time you use std.algorithm.

 It's not a joke! Such things must be mentioned in docs or D is
 unusable for non-experienced D developers.

 http://d.puremagic.com/issues/show_bug.cgi?id=7965

Looks to me like a frame pointer bug for the delegate (Or lack of it?)... Based on the setup, it should also be illegal to pass the struct outside of the scope it's in due to the delegate in the struct (Unless the variable(s) in question are static).

Passing the struct outside of the scope it is in must be legal and create a heap frame if it references any of the stack variables. What delegates are you talking about?
Jun 16 2012
parent Timon Gehr <timon.gehr gmx.ch> writes:
On 06/17/2012 01:45 AM, Era Scarecrow wrote:
 On Saturday, 16 June 2012 at 22:13:44 UTC, Timon Gehr wrote:
 On 06/16/2012 11:19 PM, Era Scarecrow wrote:
 On Saturday, 16 June 2012 at 20:16:52 UTC, Denis Shelomovskij wrote:
 Just want to mention again that Issue 7965 is a really nasty
 wrong-code bug that is difficult to find unless you know about it.

 I face this Issue in almost every my D program with non-trivial
 std.algorithm usage and I suppose I'm not alone.

 If there is no plans to fix it in near future this _must_ be
 mentioned in std.algorithm Page and in other places in docs because
 it's really possible to avoid it every time you use std.algorithm.

 It's not a joke! Such things must be mentioned in docs or D is
 unusable for non-experienced D developers.

 http://d.puremagic.com/issues/show_bug.cgi?id=7965

Looks to me like a frame pointer bug for the delegate (Or lack of it?)... Based on the setup, it should also be illegal to pass the struct outside of the scope it's in due to the delegate in the struct (Unless the variable(s) in question are static).

Passing the struct outside of the scope it is in must be legal and create a heap frame if it references any of the stack variables. What delegates are you talking about?

I had the impression that a function referencing the outer frame automatically was a delegate; Maybe I just messed up on the terms.. void func(){ int x; void y(){x++;}; //equal to?? auto y = delegate void(){x++;}; }

I see. What actually happens looks more like this: struct StackContext{ int x; } StackContext x; static void y(StackContext* context){ context.x++; } No delegate is created until the address of the nested function is taken. If such a delegate is suspected to escape the frame, the StackContext is allocated on the heap instead.
Jun 16 2012
prev sibling parent "Era Scarecrow" <rtcvb32 yahoo.com> writes:
On Saturday, 16 June 2012 at 22:13:44 UTC, Timon Gehr wrote:
 On 06/16/2012 11:19 PM, Era Scarecrow wrote:
 On Saturday, 16 June 2012 at 20:16:52 UTC, Denis Shelomovskij 
 wrote:
 Just want to mention again that Issue 7965 is a really nasty 
 wrong-code bug that is difficult to find unless you know 
 about it.

 I face this Issue in almost every my D program with 
 non-trivial std.algorithm usage and I suppose I'm not alone.

 If there is no plans to fix it in near future this _must_ be 
 mentioned in std.algorithm Page and in other places in docs 
 because it's really possible to avoid it every time you use 
 std.algorithm.

 It's not a joke! Such things must be mentioned in docs or D 
 is unusable for non-experienced D developers.

 http://d.puremagic.com/issues/show_bug.cgi?id=7965

Looks to me like a frame pointer bug for the delegate (Or lack of it?)... Based on the setup, it should also be illegal to pass the struct outside of the scope it's in due to the delegate in the struct (Unless the variable(s) in question are static).

Passing the struct outside of the scope it is in must be legal and create a heap frame if it references any of the stack variables. What delegates are you talking about?

I had the impression that a function referencing the outer frame automatically was a delegate; Maybe I just messed up on the terms.. void func(){ int x; void y(){x++;}; //equal to?? auto y = delegate void(){x++;}; }
Jun 16 2012