[PATCH] `nonnull` argument attribute.

[Luqman Aden]

ping


On Fri, Apr 18, 2014 at 9:12 PM, Philip Reames <listmail at philipreames.com>wrote:

> Good catch.  This is a real corner case in the attribute specification.
>  Possibly we should document the distinction somewhere?
>
> Which reminds me, we'll need doc changes (LangRef) to describe the new
> attribute.
>
> Philip
>
>
> On 04/17/2014 10:43 PM, Hal Finkel wrote:
>
>> ----- Original Message -----
>>
>>> From: "Nick Lewycky" <nicholas at mxc.ca>
>>> To: reviews+D3389+public+a85d4f162cd7a6e0 at reviews.llvm.org
>>> Cc: llvm-commits at cs.uiuc.edu
>>> Sent: Thursday, April 17, 2014 10:52:35 PM
>>> Subject: Re: [PATCH] `nonnull` argument attribute.
>>>
>>> Your change to lib/IR/Value.cpp is wrong, a nonnull pointer is not
>>> necessarily dereferenceable.
>>>
>>> %a = inttoptr i32 123456 to i32*
>>> call void @foo(i32* %a nonnull)
>>>
>>> It's nonnull, but not dereferenceable.
>>>
>> I'll add that we really should have a dereferenceable attribute, IMHO,
>> but as Nick said, it needs to be a separate from notnull. I think that for
>> dereferenceable we'll want to have a more involved discussion because we'll
>> need to decide if it affects derived pointers, should it have a size
>> parameter, etc.
>>
>>   -Hal
>>
>>  Nick
>>>
>>> Luqman Aden wrote:
>>>
>>>>     Added test.
>>>>
>>>> http://reviews.llvm.org/D3389
>>>>
>>>> CHANGE SINCE LAST DIFF
>>>>     http://reviews.llvm.org/D3389?vs=8552&id=8553#toc
>>>>
>>>> Files:
>>>>     lib/AsmParser/LLToken.h
>>>>     lib/AsmParser/LLParser.cpp
>>>>     lib/AsmParser/LLLexer.cpp
>>>>     lib/Bitcode/Writer/BitcodeWriter.cpp
>>>>     lib/Bitcode/Reader/BitcodeReader.cpp
>>>>     lib/IR/Function.cpp
>>>>     lib/IR/Attributes.cpp
>>>>     lib/Analysis/ValueTracking.cpp
>>>>     test/Bitcode/attributes.ll
>>>>     test/Analysis/BasicAA/nonnull.ll
>>>>     include/llvm/Bitcode/LLVMBitCodes.h
>>>>     include/llvm/IR/Attributes.h
>>>>     include/llvm/IR/Argument.h
>>>>
>>>>
>>>>
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