digitalmars.D.bugs - [Issue 3551] New: nested struct => dmd adds a hidden pointer
- d-bugmail puremagic.com (40/40) Nov 25 2009 http://d.puremagic.com/issues/show_bug.cgi?id=3551
- d-bugmail puremagic.com (14/43) Nov 25 2009 http://d.puremagic.com/issues/show_bug.cgi?id=3551
- d-bugmail puremagic.com (10/10) Nov 30 2009 http://d.puremagic.com/issues/show_bug.cgi?id=3551
- d-bugmail puremagic.com (11/11) Dec 06 2009 http://d.puremagic.com/issues/show_bug.cgi?id=3551
http://d.puremagic.com/issues/show_bug.cgi?id=3551 Summary: nested struct => dmd adds a hidden pointer Product: D Version: 2.036 Platform: Other OS/Version: All Status: NEW Keywords: wrong-code Severity: regression Priority: P2 Component: DMD AssignedTo: nobody puremagic.com ReportedBy: nfxjfg gmail.com Take this code: void main() { struct X { int x; int bar() { return x; } } X s; } dmd2 adds a hidden pointer to struct X. That means s.sizeof==8. For extra buggyness, the hidden pointer appears in s.tupleof. This silently breaks many uses of structs. Especially it breaks C compatibility, the bit-layout for asm code, and whatever you think of. At the very least, dmd should never add a hidden pointer if that hidden pointer gets is not needed. Actually, I consider this an anti-feature, because dmd should NEVER add (non-static) hidden fields to structs. The request to fix or remove this feature is part of this bug report. The language spec should also be fixed. Note that even if the hidden pointer is added only if needed, this is still bug-prone, because it requires complicated semantic analysis just to tell, whether the struct's size got messed up. I propose to add a "dynamic" attribute for nested structs. If a struct is tagged with "dynamic", it can reference variables from its enclosing scope, and may need a hidden pointer. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Nov 25 2009
http://d.puremagic.com/issues/show_bug.cgi?id=3551 Don <clugdbug yahoo.com.au> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |clugdbug yahoo.com.auTake this code: void main() { struct X { int x; int bar() { return x; } } X s; } dmd2 adds a hidden pointer to struct X. That means s.sizeof==8. For extra buggyness, the hidden pointer appears in s.tupleof. This silently breaks many uses of structs. Especially it breaks C compatibility, the bit-layout for asm code, and whatever you think of. At the very least, dmd should never add a hidden pointer if that hidden pointer gets is not needed. Actually, I consider this an anti-feature, because dmd should NEVER add (non-static) hidden fields to structs. The request to fix or remove this feature is part of this bug report. The language spec should also be fixed. Note that even if the hidden pointer is added only if needed, this is still bug-prone, because it requires complicated semantic analysis just to tell, whether the struct's size got messed up. I propose to add a "dynamic" attribute for nested structs. If a struct is tagged with "dynamic", it can reference variables from its enclosing scope, and may need a hidden pointer.In the spec, that's what static structs are for. Nested _anything_ has this behaviour. Declare it as a static struct if you don't want the hidden pointer. Please close this bug as invalid, and create a new one: "static nested structs are not implemented". -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Nov 25 2009
http://d.puremagic.com/issues/show_bug.cgi?id=3551 Walter Bright <bugzilla digitalmars.com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |bugzilla digitalmars.com 02:22:08 PST --- Declaring the struct as static should work, I'll make that fix. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Nov 30 2009
http://d.puremagic.com/issues/show_bug.cgi?id=3551 Walter Bright <bugzilla digitalmars.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution| |FIXED 00:55:04 PST --- Fixed dmd 2.037 -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Dec 06 2009