zahed khurasani <sdzahed@xxxxxxxxx> writes: > Let me try again. If I have an expression of the from a[i][10], then I > need to insert the > following function call into the tree: > check_deref(a[i][10], sizeof(a[i][10]), &a[i][10]); > > I tried POINTER_PLUS_EXPR. It fails at the same place. However, it > works if I have > constant indices like a[1][10]. > > Hope this is clearer than before. Thanks! Exactly how does it fail if you have non-constant indices? Ian > On Fri, Mar 9, 2012 at 7:48 PM, Ian Lance Taylor <iant@xxxxxxxxxx> wrote: >> zahed khurasani <sdzahed@xxxxxxxxx> writes: >> >>> I need to build a node that is equivalent to the address of the memory >>> being derenferenced. >>> MEM_REF would help with the first parameter. But what about the third parameter? >>> I would need an ADDR_EXPR for this parameter. However, the code I am using >>> is failing. >>> Thanks for the help. >> >> I'm not sure I completely understand, but I will say that a >> POINTER_PLUS_EXPR would be the address equivalent of a MEM_REF. >> >> Ian >> >>> On Fri, Mar 9, 2012 at 6:04 PM, Ian Lance Taylor <iant@xxxxxxxxxx> wrote: >>>> zahed khurasani <sdzahed@xxxxxxxxx> writes: >>>> >>>>> My check function accepts three parameters: the value being >>>>> dereferenced, the size of the object and the address in memory. I am >>>>> using the following two lines to get the third address parameter. >>>>> >>>>> addr = build1 (ADDR_EXPR, build_pointer_type (type), t); // t is the >>>>> ARRAY_REF node >>>>> fold_convert_loc(location, ptr_type_node, addr); // type case to void * >>>>> >>>>> However, this is failing whenever the array_ref contains a >>>>> non-constant expression, say like a[i+1]. The specific failure is >>>>> inside the expand_expr_real_1 method in the file expr.c. Looks like >>>>> such non-constant indices are not allowed at this stage in the >>>>> compilation (I've inserted the pass just before lowering to RTL >>>>> happens). >>>>> >>>>> My question is, what would be the right way to get the address? I am >>>>> looking for something that will preferably work for all dereferences >>>>> like MEM_REF, INDIRECT_REF etc. >>>> >>>> ARRAY_REF certainly permits non-constant indices, so I don't think that >>>> is your problem. >>>> >>>> However, MEM_REF is the most general memory reference expression. >>>> >>>> Ian
