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

[Marco Elver via Phabricator via cfe-commits]

melver 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);
----------------
ztong0001 wrote:
> ztong0001 wrote:
> > 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.
> BTW: Just to double check we are on the same page
> 
> when no_sanitize(bounds) is provided, fsanitize=array-bounds is also disabled -- right ? I can confirm this attribute is also affecting array-bounds as this is handled in clang side and we are setting llvm::Attribute::NoSanitizeBounds so that clang's array-bounds can also see this.
> 
> I will also add another test for -fsanitize=array-bounds
Well, no_sanitize("bounds") already worked for array-bounds before this patch. But adding more tests never hurt.


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

https://reviews.llvm.org/D119816