[LLVMdev] Reference Manual Clarifications 2

Jon Sargeant delta17 at cox.net
Fri Apr 4 20:15:28 PDT 2008

Jon Sargeant wrote:
> Chris Lattner wrote:
>> On Mon, 31 Mar 2008, Jon Sargeant wrote:
>>> I'm attaching another round of changes.  Please verify that they are correct.
>> Applied with edits:
>> http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20080331/060556.html
>> I figured out what your patches don't apply.  Something (your web browser, 
>> editor, etc) is stripping trailing whitespace.
>> -Chris
> Hmm, I realized that the alignment doesn't have a type in front of it 
> (unlike NumElements) so it's reasonably clear that it's a constant. 
> Saying "constant alignment" isn't necessary.
> Regarding malloc, I think your wording isn't clear enough: "Allocating 
> zero bytes is undefined."  My understanding is that an undefined 
> operation is illegal; however, the implementation is not required to 
> diagnose it.  Allocating zero bytes is legal; it's just that the result 
> is meaningless.  Consider rewording as "Allocating zero bytes is legal, 
> but the result is undefined.  The result of a zero-sized allocation is a 
> valid argument for free."
> Regarding free, I also think your wording isn't clear enough: "If the 
> pointer is null, the result is undefined."  The free result is void.
> Consider rewording as "If the pointer is null, the operation is valid 
> but does not free the pointer."
> Regarding alloca, please add "The operation is undefined if there is 
> insufficient memory available."
> Regarding malloc and alloca, I realized that the size is unsigned, so a 
> negative value for NumElements is impossible.  I suggest replacing "it 
> is the number of elements allocated" with "it is the UNSIGNED number of 
> elements allocated".
> Regarding shl, ashr, and lshr, please add "The second argument is 
> interpreted as an unsigned value."
> Regarding unwind, replace "The 'unwind' intrinsic" with "The 'unwind' 
> instruction"
> I'm working on another set of changes now.  If it's not too much 
> trouble, it would be more convenient for me to post the changes (as I've 
> done in this e-mail) and let you integrate them into LangRef.html.
> Best Regards,
> Jon

Chris, I'm awaiting your reply.

Best Regards,

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