search for: ptrdiff

... You can extract > information about a pointer by a inttoptr, a load of part or all of > the address from memory, pointer comparisons, and possibly some other > ways I'm not thinking of. > >> This would be helpful to understand >>  http://llvm.org/docs/GetElementPtr.html#ptrdiff >> http://llvm.org/docs/GetElementPtr.html#null >> which suggest that we can do some 'wild' pointer arithmetic by >> inttoptr and ptrtoint. >> >> For example, given a pointer p, can we safely do? >>   i = ptrtoint p; >>   j = i + null; >>   q...

...; information about a pointer by a inttoptr, a load of part or all of >> the address from memory, pointer comparisons, and possibly some other >> ways I'm not thinking of. >> >>> This would be helpful to understand >>>  http://llvm.org/docs/GetElementPtr.html#ptrdiff >>> http://llvm.org/docs/GetElementPtr.html#null >>> which suggest that we can do some 'wild' pointer arithmetic by >>> inttoptr and ptrtoint. >>> >>> For example, given a pointer p, can we safely do? >>>   i = ptrtoint p; >>>  ...

...a pointer by a inttoptr, a load of part or all of >>> the address from memory, pointer comparisons, and possibly some other >>> ways I'm not thinking of. >>> >>>> This would be helpful to understand >>>>  http://llvm.org/docs/GetElementPtr.html#ptrdiff >>>> http://llvm.org/docs/GetElementPtr.html#null >>>> which suggest that we can do some 'wild' pointer arithmetic by >>>> inttoptr and ptrtoint. >>>> >>>> For example, given a pointer p, can we safely do? >>>>   i = pt...

...s for that to be the case. You can extract information about a pointer by a inttoptr, a load of part or all of the address from memory, pointer comparisons, and possibly some other ways I'm not thinking of. > This would be helpful to understand >  http://llvm.org/docs/GetElementPtr.html#ptrdiff > http://llvm.org/docs/GetElementPtr.html#null > which suggest that we can do some 'wild' pointer arithmetic by > inttoptr and ptrtoint. > > For example, given a pointer p, can we safely do? >   i = ptrtoint p; >   j = i + null; >   q = inttoptr j; >   v = load q;...

...p is not out-of-bound no matter which p_j is taken as a base pointer? Could anyone explain this rule more precisely? For example, how can we find " all pointer values that contribute (directly or indirectly)" ? This would be helpful to understand http://llvm.org/docs/GetElementPtr.html#ptrdiff http://llvm.org/docs/GetElementPtr.html#null which suggest that we can do some 'wild' pointer arithmetic by inttoptr and ptrtoint. For example, given a pointer p, can we safely do? i = ptrtoint p; j = i + null; q = inttoptr j; v = load q; Thanks a lot. On Mon, Apr 4, 2011 at...

...r travels through memory (i.e., it is stored into memory by a store instruction and loaded later by a load instruction). An enhanced version of DSA which tracks pointers through integers could handle this. > This would be helpful to understand > http://llvm.org/docs/GetElementPtr.html#ptrdiff > http://llvm.org/docs/GetElementPtr.html#null > which suggest that we can do some 'wild' pointer arithmetic by > inttoptr and ptrtoint. > > For example, given a pointer p, can we safely do? > i = ptrtoint p; > j = i + null; > q = inttoptr j; > v =...

On Mon, Apr 4, 2011 at 7:10 AM, John Criswell <criswell at illinois.edu> wrote: > On 4/4/2011 6:45 PM, Eli Friedman wrote: >> >> On Mon, Apr 4, 2011 at 5:02 PM, Arushi Aggarwal<arushi987 at gmail.com> >>  wrote: >>> >>>> Hi, >>>> Is it correct to convert, >>>>   %196 = load i32* %195, align 8                

On 4/4/2011 6:45 PM, Eli Friedman wrote: > On Mon, Apr 4, 2011 at 5:02 PM, Arushi Aggarwal<arushi987 at gmail.com> wrote: >> >>> Hi, >>> Is it correct to convert, >>> %196 = load i32* %195, align 8 ;<i32> [#uses=1] >>> %197 = zext i32 %196 to i64 ;<i64> [#uses=1] >>> %198 =