Invalid method called - reduced test case

Mar 03, 2006

Tom S

Mar 06, 2006

Thomas Kuehne

Mar 06, 2006

John Reimer

Mar 06, 2006

Tom S

Mar 07, 2006

Thomas Kuehne

DMD seems to be picky about the order of files passed to it. The attached program is a reduced version of what Ant encountered while working on Duit. I believe this is the same bug that Tyler reported regarding DWT. The .zip archive contains 3 D modules: a.d, b.d and main.d When compiled using: dmd b.d a.d main.d ...the resulting executable will be buggy. More specifically, an assertion (that I put in a function which should never be called) will fail :) The behavior is the same if one builds a .lib or .a file using dmd -c b.d a.d ...and then links to main.d Tested on Windows and Linux using the #D compiler farm ;) -- -----BEGIN GEEK CODE BLOCK----- Version: 3.1 GCS/M d-pu s+: a-->----- C+++$>++++ UL P+ L+ E--- W++ N++ o? K? w++ !O !M V? PS- PE- Y PGP t 5 X? R tv-- b DI- D+ G e>+++ h>++ !r !y ------END GEEK CODE BLOCK------ Tomasz Stachowiak /+ a.k.a. h3r3tic +/

Tom S schrieb am 2006-03-03: > > DMD seems to be picky about the order of files passed to it. The > attached program is a reduced version of what Ant encountered while > working on Duit. I believe this is the same bug that Tyler reported > regarding DWT. > The .zip archive contains 3 D modules: a.d, b.d and main.d > > When compiled using: > dmd b.d a.d main.d > > ...the resulting executable will be buggy. More specifically, an assertion (that I put in a function which should never be called) will fail :) > > The behavior is the same if one builds a .lib or .a file using dmd -c b.d a.d > > ...and then links to main.d > > Tested on Windows and Linux using the #D compiler farm ;) Your test case seems to be broken: === a.d === private import b; class Foo : Bar { void foo() { assert(false); // this should never be called ! } } === b.d === class Bar { private import a; void bar() { printf("Bar.bar()\n"); } } === main.d === private import a; void main() { (new Foo()).bar(); } You call Foo.bar in main - that's exactly the function you didn't expect to execute. The real bug is: the private of "private import a;" isn't enforced and thus interpreted as "import a;" - the protection attributes are known not to work properly in many situations. Thomas

March 06, 2006

Re: Invalid method called - reduced test case

Posted by John Reimer
in reply to Thomas Kuehne

Permalink

John Reimer

Posted in reply to Thomas Kuehne

Permalink

Thomas Kuehne wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> Tom S schrieb am 2006-03-03:
>> DMD seems to be picky about the order of files passed to it. The attached program is a reduced version of what Ant encountered while working on Duit. I believe this is the same bug that Tyler reported regarding DWT.
>> The .zip archive contains 3 D modules: a.d, b.d and main.d
>>
>> When compiled using:
>> dmd b.d a.d main.d
>>
>> ...the resulting executable will be buggy. More specifically, an assertion (that I put in a function which should never be called) will fail :)
>>
>> The behavior is the same if one builds a .lib or .a file using
>> dmd -c b.d a.d
>>
>> ...and then links to main.d
>>
>> Tested on Windows and Linux using the #D compiler farm ;)
> 
> Your test case seems to be broken:
> 
> === a.d ===
> private import b;
> 
> class Foo : Bar {
> 	void foo() {
> 		assert(false);	// this should never be called !
> 	}
> }
> 
> === b.d ===
> class Bar {
> 	private import a;
> 
> 	void bar() {
> 		printf("Bar.bar()\n");
> 	}
> }
> 
> === main.d ===
> private import a;
> 
> void main() {
> 	(new Foo()).bar();
> }
> 
> 
> You call Foo.bar in main - that's exactly the function you didn't expect
> to execute.
> 
> The real bug is: the private of "private import a;" isn't enforced and thus
> interpreted as "import a;" - the protection attributes are known not to
> work properly in many situations.
> 
> Thomas
> 
> 
> -----BEGIN PGP SIGNATURE-----
> 
> iD8DBQFEDASk3w+/yD4P9tIRAljXAKDCRA+aN1NNiC4cgMyX8WNyXjYjkQCgwViR
> rw5WgcU4IBE4e64MtO1zzUA=
> =NlAj
> -----END PGP SIGNATURE-----


How is it broken?

I fail to understand, then, why Foo.foo() is called when a call to Foo.bar() is made?  Their function signatures are quite different, no? Are the vtables getting reassigned from the compile/link order?

Change the compile order with this:

dmd main.d a.d b.d

and Foo.bar() is called as expected.  This seems to be a compile order-related issue.  Why does this work just because the objects are built in a different order?

In what situation would we see main.d /not/ put first in the build list?

This does appear to be a dangerous problem, nonetheless...

-JJR

Thomas Kuehne wrote: > Your test case seems to be broken: > > === a.d === > private import b; > > class Foo : Bar { > void foo() { > assert(false); // this should never be called ! > } > } > > === b.d === > class Bar { > private import a; > > void bar() { > printf("Bar.bar()\n"); > } > } > > === main.d === > private import a; > > void main() { > (new Foo()).bar(); > } > > > You call Foo.bar in main - that's exactly the function you didn't expect > to execute. Wrong. I tell it to call Foo.bar but Foo.foo gets called (the function that contains the assert) :) The order in which these modules are passed to the compiler is important. -- -----BEGIN GEEK CODE BLOCK----- Version: 3.1 GCS/M d-pu s+: a-->----- C+++$>++++ UL P+ L+ E--- W++ N++ o? K? w++ !O !M V? PS- PE- Y PGP t 5 X? R tv-- b DI- D+ G e>+++ h>++ !r !y ------END GEEK CODE BLOCK------ Tomasz Stachowiak /+ a.k.a. h3r3tic +/

Forums