r346548 - Use the correct address space when bitcasting func pointer to int pointer

[Roman Lebedev via cfe-commits]

The codegen change can't be tested?
On Fri, Nov 9, 2018 at 10:44 PM Dylan McKay via cfe-commits
<cfe-commits at lists.llvm.org> wrote:
>
> Author: dylanmckay
> Date: Fri Nov  9 11:42:05 2018
> New Revision: 346548
>
> URL: http://llvm.org/viewvc/llvm-project?rev=346548&view=rev
> Log:
> Use the correct address space when bitcasting func pointer to int pointer
>
> When we cast a function pointer to an int pointer, at some pointer later
> it gets bitcasted back to a function and called.
>
> In backends that have a nonzero program memory address space specified
> in the data layout, the old code would lose the address space data. When
> LLVM later attempted to generate the bitcast from i8* to i8(..)*
> addrspace(1), it would fail because the pointers are not in the same
> address space.
>
> With this patch, the address space of the function will carry on to the
> address space of the i8* pointer. This is because all function pointers
> in Harvard architectures need to be assigned to the correct address
> space.
>
> This has no effect to any in-tree backends except AVR.
>
> Modified:
>     cfe/trunk/lib/CodeGen/CGException.cpp
>
> Modified: cfe/trunk/lib/CodeGen/CGException.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGException.cpp?rev=346548&r1=346547&r2=346548&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CGException.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CGException.cpp Fri Nov  9 11:42:05 2018
> @@ -250,7 +250,11 @@ static llvm::Constant *getPersonalityFn(
>  static llvm::Constant *getOpaquePersonalityFn(CodeGenModule &CGM,
>                                          const EHPersonality &Personality) {
>    llvm::Constant *Fn = getPersonalityFn(CGM, Personality);
> -  return llvm::ConstantExpr::getBitCast(Fn, CGM.Int8PtrTy);
> +  llvm::PointerType* Int8PtrTy = llvm::PointerType::get(
> +      llvm::Type::getInt8Ty(CGM.getLLVMContext()),
> +      CGM.getDataLayout().getProgramAddressSpace());
> +
> +  return llvm::ConstantExpr::getBitCast(Fn, Int8PtrTy);
>  }
>
>  /// Check whether a landingpad instruction only uses C++ features.
>
>
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