[lld] r234580 - [ARM] Improve veneer handling and introduce handlePlain method

[Rui Ueyama]

On Fri, Apr 10, 2015 at 2:54 AM, Denis Protivensky <
dprotivensky at accesssoftek.com> wrote:

> Author: denis-protivensky
> Date: Fri Apr 10 04:54:10 2015
> New Revision: 234580
>
> URL: http://llvm.org/viewvc/llvm-project?rev=234580&view=rev
> Log:
> [ARM] Improve veneer handling and introduce handlePlain method
>
> Handle veneers only for call-like relocations.
>
> Modified:
>     lld/trunk/lib/ReaderWriter/ELF/ARM/ARMRelocationPass.cpp
>
> Modified: lld/trunk/lib/ReaderWriter/ELF/ARM/ARMRelocationPass.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/ELF/ARM/ARMRelocationPass.cpp?rev=234580&r1=234579&r2=234580&view=diff
>
> ==============================================================================
> --- lld/trunk/lib/ReaderWriter/ELF/ARM/ARMRelocationPass.cpp (original)
> +++ lld/trunk/lib/ReaderWriter/ELF/ARM/ARMRelocationPass.cpp Fri Apr 10
> 04:54:10 2015
> @@ -297,12 +297,14 @@ template <class Derived> class ARMReloca
>      case R_ARM_MOVT_ABS:
>      case R_ARM_THM_MOVW_ABS_NC:
>      case R_ARM_THM_MOVT_ABS:
> +      static_cast<Derived *>(this)->handlePlain(atom, ref);
> +      break;
>      case R_ARM_THM_CALL:
>      case R_ARM_CALL:
>      case R_ARM_JUMP24:
>      case R_ARM_THM_JUMP24:
>      case R_ARM_THM_JUMP11:
> -      static_cast<Derived *>(this)->handleIFUNC(atom, ref);
> +      static_cast<Derived *>(this)->handlePlain(atom, ref);
>        static_cast<Derived *>(this)->handleVeneer(atom, ref);


I believe this static_cast is to eliminate vtable lookup, but do you think
we really need this? This is not written by you nor me, so maybe neither of
us can't answer to the question, but it feels like premature optimization
to me.

       break;
>      case R_ARM_TLS_IE32:
> @@ -666,6 +668,11 @@ public:
>    ARMStaticRelocationPass(const elf::ARMLinkingContext &ctx)
>        : ARMRelocationPass(ctx) {}
>
> +  /// \brief Handle ordinary relocation references.
> +  std::error_code handlePlain(const DefinedAtom &atom, const Reference
> &ref) {
> +    return handleIFUNC(atom, ref);
> +  }
> +
>    /// \brief Get the veneer for ARM B/BL instructions.
>    const VeneerAtom *getVeneer_ARM_B_BL(const DefinedAtom *da,
>                                         StringRef secName) {
> @@ -728,6 +735,11 @@ public:
>    ARMDynamicRelocationPass(const elf::ARMLinkingContext &ctx)
>        : ARMRelocationPass(ctx) {}
>
> +  /// \brief Handle ordinary relocation references.
> +  std::error_code handlePlain(const DefinedAtom &atom, const Reference
> &ref) {
> +    return handleIFUNC(atom, ref);
> +  }
> +
>    /// \brief Get the veneer for ARM B/BL instructions.
>    const VeneerAtom *getVeneer_ARM_B_BL(const DefinedAtom *da,
>                                         StringRef secName) {
>
>
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