Initial submission for the attribute group feature.

Attribute groups are of the form:

  #0 = attributes { noinline "no-sse" "cpu"="cortex-a8" alignstack=4 }

Target-dependent attributes are represented as strings. Attributes can have
optional values associated with them. E.g., the "cpu" attribute has the value
"cortex-a8".

Target-independent attributes are listed as enums inside the attribute classes.

Multiple attribute groups can be referenced by the same object. In that case,
the attributes are merged together.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174493 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling
2013-02-06 06:52:58 +00:00
parent 97fe3d9511
commit 95ce4c2ffb
6 changed files with 197 additions and 41 deletions

View File

@@ -737,6 +737,36 @@ The compiler declares the supported values of *name*. Specifying a
collector which will cause the compiler to alter its output in order to
support the named garbage collection algorithm.
.. _attrgrp:
Attribute Groups
----------------
Attribute groups are groups of attributes that are referenced by objects within
the IR. They are important for keeping ``.ll`` files readable, because a lot of
functions will use the same set of attributes. In the degenerative case of a
``.ll`` file that corresponds to a single ``.c`` file, the single attribute
group will capture the important command line flags used to build that file.
An attribute group is a module-level object. To use an attribute group, an
object references the attribute group's ID (e.g. ``#37``). An object may refer
to more than one attribute group. In that situation, the attributes from the
different groups are merged.
Here is an example of attribute groups for a function that should always be
inlined, has a stack alignment of 4, and which shouldn't use SSE instructions:
.. code-block:: llvm
; Target-independent attributes:
#0 = attributes { alwaysinline alignstack=4 }
; Target-dependent attributes:
#1 = attributes { "no-sse" }
; Function @f has attributes: alwaysinline, alignstack=4, and "no-sse".
define void @f() #0 #1 { ... }
.. _fnattrs:
Function Attributes