[PATCH] D119816: [SanitizerBounds] Add support for NoSanitizeBounds function

[Tong Zhang via Phabricator via llvm-commits]

ztong0001 added inline comments.


================
Comment at: clang/lib/CodeGen/CodeGenFunction.cpp:757
         SanOpts.set(SanitizerKind::HWAddress, false);
+      if (mask & SanitizerKind::LocalBounds)
+        Fn->addFnAttr(llvm::Attribute::NoSanitizeBounds);
----------------
melver wrote:
> These 2 checks can be reduced to 1 due to SanitizerKind::Bounds including both. However, as noted, this only affects local-bounds, so I'm not sure if we want to include both -- perhaps for completeness it makes sense, but in the array-bounds only case this attribute will be a nop (AFAIK).
> 
> Also, I think we don't want to attach the attribute if bounds checking isn't enabled -- at least it seems unnecessary to do so.
> 
> See the following suggested change:
> 
> ```
> diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
> index 842ce0245d45..c1f3a3014a19 100644
> --- a/clang/lib/CodeGen/CodeGenFunction.cpp
> +++ b/clang/lib/CodeGen/CodeGenFunction.cpp
> @@ -740,6 +740,7 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
>    } while (false);
>  
>    if (D) {
> +    const bool SanitizeBounds = SanOpts.hasOneOf(SanitizerKind::Bounds);
>      bool NoSanitizeCoverage = false;
>  
>      for (auto Attr : D->specific_attrs<NoSanitizeAttr>()) {
> @@ -754,16 +755,15 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
>          SanOpts.set(SanitizerKind::KernelHWAddress, false);
>        if (mask & SanitizerKind::KernelHWAddress)
>          SanOpts.set(SanitizerKind::HWAddress, false);
> -      if (mask & SanitizerKind::LocalBounds)
> -        Fn->addFnAttr(llvm::Attribute::NoSanitizeBounds);
> -      if (mask & SanitizerKind::ArrayBounds)
> -        Fn->addFnAttr(llvm::Attribute::NoSanitizeBounds);
>  
>        // SanitizeCoverage is not handled by SanOpts.
>        if (Attr->hasCoverage())
>          NoSanitizeCoverage = true;
>      }
>  
> +    if (SanitizeBounds && !SanOpts.hasOneOf(SanitizerKind::Bounds))
> +      Fn->addFnAttr(llvm::Attribute::NoSanitizeBounds);
> +
>      if (NoSanitizeCoverage && CGM.getCodeGenOpts().hasSanitizeCoverage())
>        Fn->addFnAttr(llvm::Attribute::NoSanitizeCoverage);
>    }
> 
> ```
Agreed. I will revise patch and commit description.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D119816/new/

https://reviews.llvm.org/D119816