Date: Tue, 10 Sep 2002 09:12:38 -0400 (EDT) From: Andrew Gallatin <gallatin@cs.duke.edu> To: Joe Marcus Clarke <marcus@marcuscom.com> Cc: obrien@FreeBSD.ORG, alpha@FreeBSD.ORG Subject: Re: getting closer (was Re: mozilla failure on 4.6.2) Message-ID: <15741.61382.872535.426732@grasshopper.cs.duke.edu> In-Reply-To: <1031635953.342.133.camel@gyros.marcuscom.com> References: <20020906040641.GA61111@xor.obsecurity.org> <1031287598.361.2.camel@gyros.marcuscom.com> <15736.40749.986834.818558@grasshopper.cs.duke.edu> <1031329151.342.9.camel@gyros.marcuscom.com> <20020906194732.GA2244@dragon.nuxi.com> <15737.2550.488154.4401@grasshopper.cs.duke.edu> <20020907000825.GA4091@dragon.nuxi.com> <15739.43883.152090.936327@grasshopper.cs.duke.edu> <15741.2822.526047.253409@grasshopper.cs.duke.edu> <1031605410.351.90.camel@gyros.marcuscom.com> <15741.17468.701009.998323@grasshopper.cs.duke.edu> <1031635953.342.133.camel@gyros.marcuscom.com>
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Joe Marcus Clarke writes:
> Add 8 to the stack pointer ("this", right), and store it in $16.
I wish it were that simple :-(
The problem seems to be that the application code is passing the
"wrong" value in and somehow the c++ calling standard corrects it, and
we must correct it too:
impl == 0x12001c080
foo == 0x12001c080
bar == 0x12001c088
Notice how "bar" = (char *)impl + 8 ?
Somehow, when doing a "direct" call, the "this" pointer ends up as the
impl pointer, not as the "bar" pointer, even if "bar" is used in the
call.
However, in the "invoke" code, we get literally what we asked for --
the "this" pointer == the "bar" pointer.
We need to somehow be able to tell that its a case like this and make
the this pointer be the impl pointer.
Appended is sample output, with some of the methods modified to print out
the this pointer.
Drew
calling direct:
1 + 1 = 2
1L + 1L = 2
2 * 2 = 4
2L * 2L = 4
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 = 55
1 + 2 = 3.000000f
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 = 55.000000
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 = 55.000000f
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 +1 15 + 16 + 17 + 18 + 19 + 20 = 210.000000f
moo cow = milk
calling via invoke:
1 + 1 = 2
1L + 1L = 2
2 * 2 = 4
2L * 2L = 4
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 = 55
1 + 2 = 3.000000f
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 = 55.000000
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 = 55.000000f
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19 + 20 = 210.000000f
moo cow = milk
impl == 0x1200160c0
foo == 0x1200160c0
bar == 0x1200160d8
Calling Foo...
direct calls:
this = 0x1200160c0
FooImpl::FooMethod1 called with i == 1, FooImpl part of a FooBarImpl
this = 0x1200160c0
FooImpl::FooMethod2 called with i == 2, FooImpl part of a FooBarImpl
invoke calls:
this = 0x1200160c0
FooImpl::FooMethod1 called with i == 1, FooImpl part of a FooBarImpl
this = 0x1200160c0
FooImpl::FooMethod2 called with i == 2, FooImpl part of a FooBarImpl
Calling Bar...
direct calls:
this = 0x1200160d8
BarImpl::BarMethod1 called with i == 1, BarImpl part of a FooBarImpl
this = 0x1200160d8
BarImpl::BarMethod2 called with i == 2, BarImpl part of a FooBarImpl
invoke calls:
this = 0x1200160d8
BarImpl::BarMethod1 called with i == 1, BarImpl part of a FooBarImpl
this = 0x1200160d8
BarImpl::BarMethod2 called with i == 2, BarImpl part of a FooBarImpl
impl == 0x12001c080
foo == 0x12001c080
bar == 0x12001c088
Calling Foo...
direct calls:
this = 0x12001c080
FooBarImpl2::FooMethod1 called with i == 1, local value = 12345678
this = 0x12001c080
FooBarImpl2::FooMethod2 called with i == 2, local value = 12345678
invoke calls:
this = 0x12001c080
FooBarImpl2::FooMethod1 called with i == 1, local value = 12345678
this = 0x12001c080
FooBarImpl2::FooMethod2 called with i == 2, local value = 12345678
Calling Bar...
direct calls:
this = 0x12001c080
FooBarImpl2::BarMethod1 called with i == 1, local value = 12345678
this = 0x12001c080
FooBarImpl2::BarMethod2 called with i == 2, local value = 12345678
invoke calls:
this = 0x12001c088
FooBarImpl2::BarMethod1 called with i == 1, local value = 0
this = 0x12001c088
FooBarImpl2::BarMethod2 called with i == 2, local value = 0
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