[llvm-commits] [llvm] r156387 - /llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp

[Stephen Hines]

The LLVM-based projects I work with don't need pre-3.0 compatibility from
this version of BitcodeReader, so it isn't a big deal to me. I am not sure
about other projects. In any case, I am not going to argue for reinstating
this code if it was never actually generated by LLVM 3.0.

Steve

On Tue, May 29, 2012 at 5:02 PM, Evan Cheng <evan.cheng at apple.com> wrote:

>
> On May 29, 2012, at 4:59 PM, Stephen Hines wrote:
>
> I wasn't sure what LLVM 3.0/3.1 emitted in this case, but figured that we
> should err on the side of caution. LLVM 3.0 accepted bitcode with these
> attributes, so it makes sense that LLVM 3.2 should still accept similar
> bitcode.
>
>
> We don't intend to maintain compatibility for pre-3.0 bitcode files.
>
> Evan
>
>
> Steve
>
> On Tue, May 29, 2012 at 4:41 PM, Nuno Lopes <nunoplopes at sapo.pt> wrote:
>
>> Why?
>> Does LLVM 3.0 or 3.1 still emit the attributes in index 0?  The
>> conclusion of the previous thread was that we only need to maintain
>> compatibility from 3.0 onwards.
>>
>> Nuno
>>
>>
>> Citando Stephen Hines <srhines at google.com>:
>>
>>
>>  Hi Nuno,
>>>
>>> Would you please revert this change as well?
>>>
>>> Thanks,
>>> Steve
>>>
>>> On Tue, May 8, 2012 at 10:07 AM, Nuno Lopes <nunoplopes at sapo.pt> wrote:
>>>
>>>  Author: nlopes
>>>> Date: Tue May  8 12:07:35 2012
>>>> New Revision: 156387
>>>>
>>>> URL: http://llvm.org/viewvc/llvm-**project?rev=156387&view=rev<http://llvm.org/viewvc/llvm-project?rev=156387&view=rev>
>>>> Log:
>>>> remove autoupgrade code for old function attributes format.
>>>> I still left another fixme regarding alignment, because I'm unsure how
>>>> to
>>>> remove that code without breaking things
>>>>
>>>> Modified:
>>>>   llvm/trunk/lib/Bitcode/Reader/**BitcodeReader.cpp
>>>>
>>>> Modified: llvm/trunk/lib/Bitcode/Reader/**BitcodeReader.cpp
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-**project/llvm/trunk/lib/**
>>>> Bitcode/Reader/BitcodeReader.**cpp?rev=156387&r1=156386&r2=**
>>>> 156387&view=diff<http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp?rev=156387&r1=156386&r2=156387&view=diff>
>>>>
>>>> ==============================**==============================**
>>>> ==================
>>>> --- llvm/trunk/lib/Bitcode/Reader/**BitcodeReader.cpp (original)
>>>> +++ llvm/trunk/lib/Bitcode/Reader/**BitcodeReader.cpp Tue May  8
>>>> 12:07:35
>>>> 2012
>>>> @@ -458,12 +458,6 @@
>>>>      if (Record.size() & 1)
>>>>        return Error("Invalid ENTRY record");
>>>>
>>>> -      // FIXME : Remove this autoupgrade code in LLVM 3.0.
>>>> -      // If Function attributes are using index 0 then transfer them
>>>> -      // to index ~0. Index 0 is used for return value attributes but
>>>> used to be
>>>> -      // used for function attributes.
>>>> -      Attributes RetAttribute;
>>>> -      Attributes FnAttribute;
>>>>      for (unsigned i = 0, e = Record.size(); i != e; i += 2) {
>>>>        // FIXME: remove in LLVM 3.0
>>>>        // The alignment is stored as a 16-bit raw value from bits
>>>> 31--16.
>>>> @@ -480,34 +474,10 @@
>>>>            Attributes((Record[i+1] & (0xffffull << 32)) >> 11);
>>>>
>>>>        Record[i+1] = ReconstitutedAttr.Raw();
>>>> -        if (Record[i] == 0)
>>>> -          RetAttribute = ReconstitutedAttr;
>>>> -        else if (Record[i] == ~0U)
>>>> -          FnAttribute = ReconstitutedAttr;
>>>> -      }
>>>> -
>>>> -      Attributes OldRetAttrs = (Attribute::NoUnwind|**
>>>> Attribute::NoReturn|
>>>> -                              Attribute::ReadOnly|Attribute:**
>>>> :ReadNone);
>>>> -
>>>> -      if (FnAttribute == Attribute::None && RetAttribute !=
>>>> Attribute::None &&
>>>> -          (RetAttribute & OldRetAttrs)) {
>>>> -        if (FnAttribute == Attribute::None) { // add a slot so they get
>>>> added.
>>>> -          Record.push_back(~0U);
>>>> -          Record.push_back(0);
>>>> -        }
>>>> -
>>>> -        FnAttribute  |= RetAttribute & OldRetAttrs;
>>>> -        RetAttribute &= ~OldRetAttrs;
>>>>      }
>>>>
>>>>      for (unsigned i = 0, e = Record.size(); i != e; i += 2) {
>>>> -        if (Record[i] == 0) {
>>>> -          if (RetAttribute != Attribute::None)
>>>> -            Attrs.push_back(**AttributeWithIndex::get(0,
>>>> RetAttribute));
>>>> -        } else if (Record[i] == ~0U) {
>>>> -          if (FnAttribute != Attribute::None)
>>>> -            Attrs.push_back(**AttributeWithIndex::get(~0U,
>>>> FnAttribute));
>>>> -        } else if (Attributes(Record[i+1]) != Attribute::None)
>>>> +        if (Attributes(Record[i+1]) != Attribute::None)
>>>>          Attrs.push_back(**AttributeWithIndex::get(**Record[i],
>>>>
>>>> Attributes(Record[i+1])));
>>>>      }
>>>>
>>>>
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