llvm dev - Jun 2017 - About the concept of "materialization"

OK. About the error it’s a long story, so it’s probably better to pin some
source code here. Below is a piece of code related to my problem, clipped from
lib/Transforms/Utils/ValueMapper.cpp. I was wondering what “materialized” means
here.

Value *Mapper::mapBlockAddress(const BlockAddress &BA) {
   Function *F = cast<Function>(mapValue(BA.getFunction())); 

   // F may not have materialized its initializer.  In that case, create a
   // dummy basic block for now, and replace it once we've materialized all
   // the initializers.
   BasicBlock *BB;
   if (F->empty()) {
     DelayedBBs.push_back(DelayedBasicBlock(BA));
     BB = DelayedBBs.back().TempBB.get();
   } else {
     BB = cast_or_null<BasicBlock>(mapValue(BA.getBasicBlock()));
   }
 
   return getVM()[&BA] = BlockAddress::get(F, BB ? BB : BA.getBasicBlock());
 }

Thanks,
Pei

On 6/28/17, 10:59 AM, "陳韋任" <chenwj.cs97g at g2.nctu.edu.tw>
wrote:

    2017-06-29 1:55 GMT+08:00 Pei Wang via llvm-dev <llvm-dev at
lists.llvm.org>:
    > Bruce,
    >
    >
    >
    > Thanks for the explanation. But based on my inspection on the source
code,
    > it seems that materialization is related to lazily reading LLVM objects
    > (Module, Function, etc.) into the memory from bitcode files, which is
    > possibly useful during LTO. I’m not sure though.
    
    You probably need to give us the error message you got, or the source code
    you're reading about materialization, so that we can speak of the same
thing.
    
    Regards,
    chenwj
    
    -- 
    Wei-Ren Chen (陳韋任)
    Homepage: https://people.cs.nctu.edu.tw/~chenwj

2017-06-29 2:08 GMT+08:00 Pei Wang <pxw172 at
ist.psu.edu>:
> OK. About the error it’s a long story, so it’s probably better to pin some
source code here. Below is a piece of code related to my problem, clipped from
lib/Transforms/Utils/ValueMapper.cpp. I was wondering what “materialized” means
here.
>
> Value *Mapper::mapBlockAddress(const BlockAddress &BA) {
>    Function *F = cast<Function>(mapValue(BA.getFunction()));
>
>    // F may not have materialized its initializer.  In that case, create a
>    // dummy basic block for now, and replace it once we've materialized
all
>    // the initializers.
>    BasicBlock *BB;
>    if (F->empty()) {
>      DelayedBBs.push_back(DelayedBasicBlock(BA));
>      BB = DelayedBBs.back().TempBB.get();
>    } else {
>      BB = cast_or_null<BasicBlock>(mapValue(BA.getBasicBlock()));
>    }
>
>    return getVM()[&BA] = BlockAddress::get(F, BB ? BB :
BA.getBasicBlock());
>  }

Hi Duncan,

  Could you shed light on that? I guess the code you wrote here
relates to JIT, but I am not sure
what materialize actually means. Thanks.

Regards,
chenwj

-- 
Wei-Ren Chen (陳韋任)
Homepage: https://people.cs.nctu.edu.tw/~chenwj

> On Jun 30, 2017, at 06:14, 陳韋任 <chenwj.cs97g at g2.nctu.edu.tw>
wrote:
> 
> 2017-06-29 2:08 GMT+08:00 Pei Wang <pxw172 at ist.psu.edu>:
>> OK. About the error it’s a long story, so it’s probably better to pin
some source code here. Below is a piece of code related to my problem, clipped
from lib/Transforms/Utils/ValueMapper.cpp. I was wondering what “materialized”
means here.
>> 
>> Value *Mapper::mapBlockAddress(const BlockAddress &BA) {
>>   Function *F = cast<Function>(mapValue(BA.getFunction()));
>> 
>>   // F may not have materialized its initializer.  In that case, create
a
>>   // dummy basic block for now, and replace it once we've
materialized all
>>   // the initializers.
>>   BasicBlock *BB;
>>   if (F->empty()) {
>>     DelayedBBs.push_back(DelayedBasicBlock(BA));
>>     BB = DelayedBBs.back().TempBB.get();
>>   } else {
>>     BB = cast_or_null<BasicBlock>(mapValue(BA.getBasicBlock()));
>>   }
>> 
>>   return getVM()[&BA] = BlockAddress::get(F, BB ? BB :
BA.getBasicBlock());
>> }
> 
> 
> Hi Duncan,
> 
>  Could you shed light on that? I guess the code you wrote here
> relates to JIT, but I am not sure
> what materialize actually means. Thanks.
This is for when a bitcode file has been lazy-loaded, and you're
materializing global values (and related metadata) into the in-memory
representation.
> 
> Regards,
> chenwj
> 
> -- 
> Wei-Ren Chen (陳韋任)
> Homepage: https://people.cs.nctu.edu.tw/~chenwj