llvm dev - Mar 2011 - [LLVMdev] How to load a data from the address of unsiged long type

Now I have an address that present in a unsigned long address like the
following format:
Value* addr = CONST(0xc0008000)

But I do not know how to read the data from the above addr varaible. I
tried the following three kind of code:
1. Code:
         Value* addr = CONST(0xc0008000);
         Value* data = new LoadInst(addr, "", false, bb);
   Error:
         Segmentation fault
2. Code( use BotVastInst to vern):
       Value* addr = CONST(0xc0008000);
        a = new BitCastInst(a, PointerType::get(XgetType(Int32Ty), 0),
"", bb);
        Value* data = new LoadInst(addr, "", false, bb);
    Error:
         Bitcast requires types of same width
3. Code:
       Type const *intptr_type
cpu->dyncom_engine->exec_engine->getTargetData()->getIntPtrType(_CTX());
        Value* ptr = new IntToPtrInst(a, intptr_type, "", bb);
        Value* data = new LoadInst(ptr, "", false, bb);
   Error:
        Segmentation fault


Any person can give me some hints for my case?

Thanks
MK

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Hi Michael,
> Now I have an address that present in a unsigned long address like the
> following format:
> Value* addr = CONST(0xc0008000)
what is the type of addr?  For that matter, what is CONST - what does it do?

Ciao, Duncan.
>
> But I do not know how to read the data from the above addr varaible. I
> tried the following three kind of code:
> 1. Code:
>           Value* addr = CONST(0xc0008000);
>           Value* data = new LoadInst(addr, "", false, bb);
>     Error:
>           Segmentation fault
> 2. Code( use BotVastInst to vern):
>         Value* addr = CONST(0xc0008000);
>          a = new BitCastInst(a, PointerType::get(XgetType(Int32Ty), 0),
"", bb);
>          Value* data = new LoadInst(addr, "", false, bb);
>      Error:
>           Bitcast requires types of same width
> 3. Code:
>         Type const *intptr_type >
cpu->dyncom_engine->exec_engine->getTargetData()->getIntPtrType(_CTX());
>          Value* ptr = new IntToPtrInst(a, intptr_type, "", bb);
>          Value* data = new LoadInst(ptr, "", false, bb);
>     Error:
>          Segmentation fault
>
>
> Any person can give me some hints for my case?
>
> Thanks
> MK
>

On Mon, Mar 14, 2011 at 6:57 PM, Duncan Sands <baldrick at free.fr>
wrote:
> Hi Michael,
>
>> Now I have an address that present in a unsigned long address like the
>> following format:
>> Value* addr = CONST(0xc0008000)
>
> what is the type of addr?  For that matter, what is CONST - what does it
do?
>
> Ciao, Duncan.
I forget to interpret the CONST macro .It is defined as the following:

ConstantInt::get(getIntegerType(s), v)

It is used to transform a C language int type to llvm Integer type.

Thanks
MK
>
>>
>> But I do not know how to read the data from the above addr varaible. I
>> tried the following three kind of code:
>> 1. Code:
>>           Value* addr = CONST(0xc0008000);
>>           Value* data = new LoadInst(addr, "", false, bb);
>>     Error:
>>           Segmentation fault
>> 2. Code( use BotVastInst to vern):
>>         Value* addr = CONST(0xc0008000);
>>          a = new BitCastInst(a, PointerType::get(XgetType(Int32Ty), 0),
"", bb);
>>          Value* data = new LoadInst(addr, "", false, bb);
>>      Error:
>>           Bitcast requires types of same width
>> 3. Code:
>>         Type const *intptr_type >>
cpu->dyncom_engine->exec_engine->getTargetData()->getIntPtrType(_CTX());
>>          Value* ptr = new IntToPtrInst(a, intptr_type, "",
bb);
>>          Value* data = new LoadInst(ptr, "", false, bb);
>>     Error:
>>          Segmentation fault
>>
>>
>> Any person can give me some hints for my case?
>>
>> Thanks
>> MK
>>
>
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