[LLVMdev] Address space information dropped

[Eli Friedman]

On Tue, May 8, 2012 at 4:59 AM, Ivan Llopard <ivanllopard at gmail.com> wrote:
> Hi Eli,
>
>
> On 07/05/2012 18:15, Eli Friedman wrote:
>>
>> On Mon, May 7, 2012 at 5:15 AM, Ivan Llopard<ivanllopard at gmail.com>
>>  wrote:
>>>
>>> Hi all,
>>>
>>> Tuning my TargetAsmPrinter implementation in the back-end side, I
>>> discovered that the address space number is not passed down while
>>> emitting global variables with constant initializers. The information is
>>> dropped at AsmPrinter::EmitGlobalConstant() function call which defaults
>>> it to zero.
>>
>>
>> This sounds like a bug.
>
>
> The feature added to allow targets emit custom data directives based on the
> address space seems to be broken. However, it doesn't produce any odd
> behavior because it's not used.
> The attached patch is quite small and shows where the address space
> information is getting lost and it will correctly propagate it. It also
> avoids existent back-ends to break because of an unimplemented hook in
> MCAsmInfo.

@@ -1046,7 +1046,8 @@
       if (CPE.isMachineConstantPoolEntry())
         EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
       else
-        EmitGlobalConstant(CPE.Val.ConstVal);
+        EmitGlobalConstant(CPE.Val.ConstVal, (isa<PointerType>(Ty)) ?
+            cast<PointerType>(Ty)->getAddressSpace() : 0);
     }
   }
 }

This looks suspicious; how can an entry in the constant pool possibly
acquire an address space based on the type of the value?

-Eli