Hi Luc,
Thanks for taking the time to look into this and the fix!
Regards
Dibyendu
On 28 February 2017 at 17:35, Luc Van Oostenryck
<luc.vanoostenryck@xxxxxxxxx> wrote:
> On Tue, Feb 28, 2017 at 06:03:05PM +0100, Luc Van Oostenryck wrote:
>> On Tue, Feb 28, 2017 at 4:09 PM, Luc Van Oostenryck
>> <luc.vanoostenryck@xxxxxxxxx> wrote:
>> > There is indeed some problems regarding this, we looked a bit at this
>> > some weeks ago. However I firmly believe that the information about
>> > the type belong to the operations and not the values.
>>
>> I've taken a very quick look at this "mt->foo = (void *)0"
>> The type info is perfectly present.
>> If in sparse-llvm.c:output_op_store() you add somewhere something like:
>> fprintf(stderr, "-> %s\n", show_typename(insn->type));
>> You will see that it display the expected type: "int *".
>> This is all the type info needed: it's the type of insn->target (the
>> value to be stored)
>> and the type of the dereferencing of insn->src (the (base) address).
>>
>> The problem is that output_op_store() doesn't use this info, it tries to deduce
>> this type via pseudo_to_value() but pseudo_to_value() wrongly assumes that all
>> PSEUDO_VALUE-pseudo are integer.
>
>
> Not very pretty and incomplete but the following patch allow sparse-llvm
> to compile this:
> struct mytype {
> int *foo;
> };
>
> extern void init_mytype(struct mytype *mt);
> void init_mytype(struct mytype *mt)
> {
> mt->foo = (int *)mt;
> mt->foo = (void *)mt;
> mt->foo = (int *)0;
> mt->foo = (void *)0;
> mt->foo = (void *)(long)0;
> }
>
> It fail at " ... = (... *)1;" though.
>
>
> diff --git a/sparse-llvm.c b/sparse-llvm.c
> index 9f362b3ed..9e0450ae7 100644
> --- a/sparse-llvm.c
> +++ b/sparse-llvm.c
> @@ -306,6 +306,7 @@ static void pseudo_name(pseudo_t pseudo, char *buf)
> static LLVMValueRef pseudo_to_value(struct function *fn, struct instruction *insn, pseudo_t pseudo)
> {
> LLVMValueRef result = NULL;
> + LLVMTypeRef type;
>
> switch (pseudo->type) {
> case PSEUDO_REG:
> @@ -360,7 +361,21 @@ static LLVMValueRef pseudo_to_value(struct function *fn, struct instruction *ins
> break;
> }
> case PSEUDO_VAL:
> - result = LLVMConstInt(insn_symbol_type(fn->module, insn), pseudo->value, 1);
> + type = insn_symbol_type(fn->module, insn);
> + switch (LLVMGetTypeKind(type)) {
> + case LLVMPointerTypeKind:
> + assert(!pseudo->value);
> + result = LLVMConstPointerNull(type);
> + break;
> + case LLVMIntegerTypeKind:
> + result = LLVMConstInt(type, pseudo->value, 1);
> + break;
> + default:
> + assert(0);
> + }
> break;
> case PSEUDO_ARG: {
> result = LLVMGetParam(fn->fn, pseudo->nr - 1);
> @@ -626,6 +641,7 @@ static void output_op_store(struct function *fn, struct instruction *insn)
>
> addr = calc_memop_addr(fn, insn);
>
> target_in = pseudo_to_value(fn, insn, insn->target);
>
> /* perform store */
--
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