r243206 - [CodeGen] Don't UBSan-ize the argument to __builtin_frame_address

[Hans Wennborg]

Merged in r243653.

Cheers,
Hans

On Wed, Jul 29, 2015 at 8:59 PM, Richard Smith <richard at metafoo.co.uk> wrote:
> Aye.
>
>
> On Tue, Jul 28, 2015 at 5:57 PM, Hans Wennborg <hans at chromium.org> wrote:
>>
>> Sure. Richard, what say you?
>>
>> On Tue, Jul 28, 2015 at 3:54 PM, Pieb, Wolfgang
>> <Wolfgang_Pieb at playstation.sony.com> wrote:
>> > Hi, would it be possible to put this fix into the 3.7 branch?
>> >
>> > Thanks
>> >
>> >> -----Original Message-----
>> >> From: cfe-commits-bounces at cs.uiuc.edu [mailto:cfe-commits-
>> >> bounces at cs.uiuc.edu] On Behalf Of David Majnemer
>> >> Sent: Friday, July 24, 2015 10:57 PM
>> >> To: cfe-commits at cs.uiuc.edu
>> >> Subject: r243206 - [CodeGen] Don't UBSan-ize the argument to
>> >> __builtin_frame_address
>> >>
>> >> Author: majnemer
>> >> Date: Sat Jul 25 00:57:24 2015
>> >> New Revision: 243206
>> >>
>> >> URL: http://llvm.org/viewvc/llvm-project?rev=243206&view=rev
>> >> Log:
>> >> [CodeGen] Don't UBSan-ize the argument to __builtin_frame_address
>> >>
>> >> __builtin_frame_address requires its argument to be a constant
>> >> expression which already implies that it cannot have undefined
>> >> behavior.
>> >> However, we used EmitScalarExpr to emit the argument causing UBSan to
>> >> try to check for overflow.
>> >>
>> >> Instead, use the constant expression emission system.
>> >>
>> >> This fixes PR24256.
>> >>
>> >> Modified:
>> >>     cfe/trunk/lib/CodeGen/CGBuiltin.cpp
>> >>     cfe/trunk/test/CodeGen/integer-overflow.c
>> >>
>> >> Modified: cfe/trunk/lib/CodeGen/CGBuiltin.cpp
>> >> URL: http://llvm.org/viewvc/llvm-
>> >> project/cfe/trunk/lib/CodeGen/CGBuiltin.cpp?rev=243206&r1=243205&r2=243
>> >> 206&view=diff
>> >> =======================================================================
>> >> =======
>> >> --- cfe/trunk/lib/CodeGen/CGBuiltin.cpp (original)
>> >> +++ cfe/trunk/lib/CodeGen/CGBuiltin.cpp Sat Jul 25 00:57:24 2015
>> >> @@ -866,14 +866,14 @@ RValue CodeGenFunction::EmitBuiltinExpr(
>> >>                                        llvm::ConstantInt::get(Int32Ty,
>> >> Offset)));
>> >>    }
>> >>    case Builtin::BI__builtin_return_address: {
>> >> -    Value *Depth = EmitScalarExpr(E->getArg(0));
>> >> -    Depth = Builder.CreateIntCast(Depth, Int32Ty, false);
>> >> +    Value *Depth =
>> >> +        CGM.EmitConstantExpr(E->getArg(0), getContext().UnsignedIntTy,
>> >> + this);
>> >>      Value *F = CGM.getIntrinsic(Intrinsic::returnaddress);
>> >>      return RValue::get(Builder.CreateCall(F, Depth));
>> >>    }
>> >>    case Builtin::BI__builtin_frame_address: {
>> >> -    Value *Depth = EmitScalarExpr(E->getArg(0));
>> >> -    Depth = Builder.CreateIntCast(Depth, Int32Ty, false);
>> >> +    Value *Depth =
>> >> +        CGM.EmitConstantExpr(E->getArg(0), getContext().UnsignedIntTy,
>> >> + this);
>> >>      Value *F = CGM.getIntrinsic(Intrinsic::frameaddress);
>> >>      return RValue::get(Builder.CreateCall(F, Depth));
>> >>    }
>> >>
>> >> Modified: cfe/trunk/test/CodeGen/integer-overflow.c
>> >> URL: http://llvm.org/viewvc/llvm-
>> >> project/cfe/trunk/test/CodeGen/integer-
>> >> overflow.c?rev=243206&r1=243205&r2=243206&view=diff
>> >> =======================================================================
>> >> =======
>> >> --- cfe/trunk/test/CodeGen/integer-overflow.c (original)
>> >> +++ cfe/trunk/test/CodeGen/integer-overflow.c Sat Jul 25 00:57:24 2015
>> >> @@ -72,4 +72,11 @@ void test1() {
>> >>    // TRAPV: add i8 {{.*}}, 1
>> >>    // CATCH_UB: add i8 {{.*}}, 1
>> >>    ++PR9350;
>> >> +
>> >> +  // PR24256: don't instrument __builtin_frame_address.
>> >> +  __builtin_frame_address(0 + 0);
>> >> +  // DEFAULT:  call i8* @llvm.frameaddress(i32 0)
>> >> +  // WRAPV:    call i8* @llvm.frameaddress(i32 0)
>> >> +  // TRAPV:    call i8* @llvm.frameaddress(i32 0)
>> >> +  // CATCH_UB: call i8* @llvm.frameaddress(i32 0)
>> >>  }
>> >>
>> >>
>> >> _______________________________________________
>> >> cfe-commits mailing list
>> >> cfe-commits at cs.uiuc.edu
>> >> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
>
>