Commit Graph

2 Commits

Author SHA1 Message Date
David Majnemer
39a09d2b7c IR: Change inalloca's grammar a bit
The grammar for LLVM IR is not well specified in any document but seems
to obey the following rules:

 - Attributes which have parenthesized arguments are never preceded by
   commas.  This form of attribute is the only one which ever has
   optional arguments.  However, not all of these attributes support
   optional arguments: 'thread_local' supports an optional argument but
   'addrspace' does not.  Interestingly, 'addrspace' is documented as
   being a "qualifier".  What constitutes a qualifier?  I cannot find a
   definition.

 - Some attributes use a space between the keyword and the value.
   Examples of this form are 'align' and 'section'.  These are always
   preceded by a comma.

 - Otherwise, the attribute has no argument.  These attributes do not
   have a preceding comma.

Sometimes an attribute goes before the instruction, between the
instruction and it's type, or after it's type.  'atomicrmw' has
'volatile' between the instruction and the type while 'call' has 'tail'
preceding the instruction.

With all this in mind, it seems most consistent for 'inalloca' on an
'inalloca' instruction to occur before between the instruction and the
type.  Unlike the current formulation, there would be no preceding
comma.  The combination 'alloca inalloca' doesn't look particularly
appetizing, perhaps a better spelling of 'inalloca' is down the road.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203376 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-09 06:41:58 +00:00
Reid Kleckner
3cbfa1617f Add an inalloca flag to allocas
Summary:
The only current use of this flag is to mark the alloca as dynamic, even
if its in the entry block.  The stack adjustment for the alloca can
never be folded into the prologue because the call may clear it and it
has to be allocated at the top of the stack.

Reviewers: majnemer

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D2571

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199525 91177308-0d34-0410-b5e6-96231b3b80d8
2014-01-17 23:58:17 +00:00