2385 – spec says all structs are returned via hidden pointer on linux, but it uses registers

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Issue 2385 - spec says all structs are returned via hidden pointer on linux, but it uses registers

Summary: spec says all structs are returned via hidden pointer on linux, but it uses r...

Status:	RESOLVED FIXED
Alias:	None
Product:	D
Classification:	Unclassified
Component:	dmd (show other issues)
Version:	D1 (retired)
Hardware:	x86 Linux
Importance :	P2 normal
Assignee:	Walter Bright
URL:
Keywords:	spec
Duplicates (1):	2648 (view as issue list)
Depends on:	2648
Blocks:	3105
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See Also:
Reported:	2008年10月02日 05:22 UTC by Tomas Lindquist Olsen
Modified:	2014年03月01日 00:36 UTC (History)
CC List:	1 user (show)

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Description Tomas Lindquist Olsen 2008年10月02日 05:22:00 UTC

the following test compiled with dmd 1.034 on linux should return via a hidden pointer parameter, but is actually returned in registers:
struct S
{
 int x;
 int z;
 static S foo()
 {
 S s = {1,2};
 return s;
 }
}
becomes
_D4test1S3fooFZS4test1S:
 push EBP
 mov EBP,ESP
 sub ESP,8
 mov dword ptr -8[EBP],1
 mov dword ptr -4[EBP],2
 mov EDX,-4[EBP]
 mov EAX,-8[EBP]
 leave
 ret

Comment 1 Walter Bright 2008年10月20日 22:20:25 UTC

Fixed dmd 1.036 and 2.020

Comment 2 Tomas Lindquist Olsen 2009年05月12日 12:30:04 UTC

the spec now says:
# For Windows, 1, 2 and 4 byte structs are returned in EAX.
# For Windows, 8 byte structs are returned in EDX,EAX, where EDX gets the most significant half.
# For other struct sizes, the return value is stored through a hidden pointer passed as an argument to the function.
I don't think just removing the info on linux is a satisfactory fix, the asm is still the same!

Comment 3 Tomas Lindquist Olsen 2009年05月12日 12:33:23 UTC

Very much related to:
http://d.puremagic.com/issues/show_bug.cgi?id=2648

Comment 4 Walter Bright 2010年11月08日 01:02:24 UTC

http://www.dsource.org/projects/phobos/changeset/2132

Comment 5 Walter Bright 2010年11月08日 01:03:29 UTC

*** Issue 2648 has been marked as a duplicate of this issue. ***