llvm dev - Jun 2018 - Proper method to initialize all LLVM Internal Data Structures?

Hi:
I'm building a small tool on top of LLVM Core Library.


```
LLVMContext context;
SMDiagnostic diag;
Module *M = parseIRFile(InputIR, diag, context).get();
  if (M == nullptr) {
    diag.print("LLVM", errs());
    exit(-1);
  }
  assert(M->isMaterialized() && "Module not
materialized!");
  PointerType *ArrayPtrTy      
M->getTypeByName("struct._Array")->getPointerTo();
```


However this piece of code crashes at Module::getTypeByName because
getContext().pImpl is NULL pointer. Other similar issues include
Module::getTypeByName results in a NULL pointer dereference because TheTable in
StringMap is not allocated/initialized.


It would be great if someone could show me what's the correct way to
initialize all this kind of internal data structures so I could focus on my
tool's logic
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I’m using LLVM6.0 Release version on macOS

Zhang
> 在 2018年6月12日，12:59，Zhang via llvm-dev <llvm-dev at lists.llvm.org>
写道：
> 
> Hi:
> I'm building a small tool on top of LLVM Core Library.
> 
> ```
> LLVMContext context;
> SMDiagnostic diag;
> Module *M = parseIRFile(InputIR, diag, context).get();
>   if (M == nullptr) {
>     diag.print("LLVM", errs());
>     exit(-1);
>   }
>   assert(M->isMaterialized() && "Module not
materialized!");
>   PointerType *ArrayPtrTy >      
M->getTypeByName("struct._Array")->getPointerTo();
> ```
> 
> However this piece of code crashes at Module::getTypeByName because
getContext().pImpl is NULL pointer. Other similar issues include
Module::getTypeByName results in a NULL pointer dereference because TheTable in
StringMap is not allocated/initialized.
> 
> It would be great if someone could show me what's the correct way to
initialize all this kind of internal data structures so I could focus on my
tool's logic
> 
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev

This line looks incorrect

Module *M = parseIRFile(InputIR, diag, context).get();

parseIRFile returns a unique_ptr, you called "get()" on it and
captured the
value of the ptr, but the temporary unique_ptr was not invalidated. So its
destructor still ran and deleted the module out from under you. You should
use std::unique_ptr<Module> M to maintain ownership.

~Craig


On Mon, Jun 11, 2018 at 10:04 PM mayuyu.io via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> I’m using LLVM6.0 Release version on macOS
>
> Zhang
>
> > 在 2018年6月12日，12:59，Zhang via llvm-dev <llvm-dev at
lists.llvm.org> 写道：
> >
> > Hi:
> > I'm building a small tool on top of LLVM Core Library.
> >
> > ```
> > LLVMContext context;
> > SMDiagnostic diag;
> > Module *M = parseIRFile(InputIR, diag, context).get();
> >   if (M == nullptr) {
> >     diag.print("LLVM", errs());
> >     exit(-1);
> >   }
> >   assert(M->isMaterialized() && "Module not
materialized!");
> >   PointerType *ArrayPtrTy > >      
M->getTypeByName("struct._Array")->getPointerTo();
> > ```
> >
> > However this piece of code crashes at Module::getTypeByName because
> getContext().pImpl is NULL pointer. Other similar issues include
> Module::getTypeByName results in a NULL pointer dereference because
> TheTable in StringMap is not allocated/initialized.
> >
> > It would be great if someone could show me what's the correct way
to
> initialize all this kind of internal data structures so I could focus on my
> tool's logic
> >
> > _______________________________________________
> > LLVM Developers mailing list
> > llvm-dev at lists.llvm.org
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
>
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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