<li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
<li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
<li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
- <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
<li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
<li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
<li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
<li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
<li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
<li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
+ <li><a href="#linkage_linkonce_odr_auto_hide">'<tt>linkonce_odr_auto_hide</tt>' Linkage</a></li>
<li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
<li><a href="#linkage_external">'<tt>external</tt>' Linkage</a></li>
<li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
<li><a href="#metadata">Metadata Nodes and Metadata Strings</a>
<ol>
<li><a href="#tbaa">'<tt>tbaa</tt>' Metadata</a></li>
+ <li><a href="#tbaa.struct">'<tt>tbaa.struct</tt>' Metadata</a></li>
<li><a href="#fpmath">'<tt>fpmath</tt>' Metadata</a></li>
<li><a href="#range">'<tt>range</tt>' Metadata</a></li>
</ol>
linker. The symbols are removed by the linker from the final linked image
(executable or dynamic library).</dd>
- <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
- <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
- of the object is not taken. For instance, functions that had an inline
- definition, but the compiler decided not to inline it. Note,
- unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
- <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
- visibility. The symbols are removed by the linker from the final linked
- image (executable or dynamic library).</dd>
-
<dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
<dd>Similar to private, but the value shows as a local symbol
(<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
be merged with equivalent globals. These linkage types are otherwise the
same as their non-<tt>odr</tt> versions.</dd>
+ <dt><tt><b><a name="linkage_linkonce_odr_auto_hide">linkonce_odr_auto_hide</a></b></tt></dt>
+ <dd>Similar to "<tt>linkonce_odr</tt>", but nothing in the translation unit
+ takes the address of this definition. For instance, functions that had an
+ inline definition, but the compiler decided not to inline it.
+ <tt>linkonce_odr_auto_hide</tt> may have only <tt>default</tt> visibility.
+ The symbols are removed by the linker from the final linked image
+ (executable or dynamic library).</dd>
+
<dt><tt><b><a name="linkage_external">external</a></b></tt></dt>
<dd>If none of the above identifiers are used, the global is externally
visible, meaning that it participates in linkage and can be used to
<dd>This indicates that the pointer parameter specifies the address of a
structure that is the return value of the function in the source program.
This pointer must be guaranteed by the caller to be valid: loads and
- stores to the structure may be assumed by the callee to not to trap. This
- may only be applied to the first parameter. This is not a valid attribute
- for return values. </dd>
+ stores to the structure may be assumed by the callee to not to trap and
+ to be properly aligned. This may only be applied to the first parameter.
+ This is not a valid attribute for return values. </dd>
<dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
<dd>This indicates that pointer values
call void asm alignstack "eieio", ""()
</pre>
-<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
- first.</p>
+<p>Inline asms also support using non-standard assembly dialects. The assumed
+ dialect is ATT. When the '<tt>inteldialect</tt>' keyword is present, the
+ inline asm is using the Intel dialect. Currently, ATT and Intel are the
+ only supported dialects. An example is:</p>
+
+<pre class="doc_code">
+call void asm inteldialect "eieio", ""()
+</pre>
+
+<p>If multiple keywords appear the '<tt>sideeffect</tt>' keyword must come
+ first, the '<tt>alignstack</tt>' keyword second and the
+ '<tt>inteldialect</tt>' keyword last.</p>
<!--
<p>TODO: The format of the asm and constraints string still need to be
</div>
+<!-- _______________________________________________________________________ -->
+<h4>
+ <a name="tbaa.struct">'<tt>tbaa.struct</tt>' Metadata</a>
+</h4>
+
+<div>
+
+<p>The <a href="#int_memcpy"><tt>llvm.memcpy</tt></a> is often used to implement
+aggregate assignment operations in C and similar languages, however it is
+defined to copy a contiguous region of memory, which is more than strictly
+necessary for aggregate types which contain holes due to padding. Also, it
+doesn't contain any TBAA information about the fields of the aggregate.</p>
+
+<p><tt>!tbaa.struct</tt> metadata can describe which memory subregions in a memcpy
+are padding and what the TBAA tags of the struct are.</p>
+
+<p>The current metadata format is very simple. <tt>!tbaa.struct</tt> metadata nodes
+ are a list of operands which are in conceptual groups of three. For each
+ group of three, the first operand gives the byte offset of a field in bytes,
+ the second gives its size in bytes, and the third gives its
+ tbaa tag. e.g.:</p>
+
+<div class="doc_code">
+<pre>
+!4 = metadata !{ i64 0, i64 4, metadata !1, i64 8, i64 4, metadata !2 }
+</pre>
+</div>
+
+<p>This describes a struct with two fields. The first is at offset 0 bytes
+ with size 4 bytes, and has tbaa tag !1. The second is at offset 8 bytes
+ and has size 4 bytes and has tbaa tag !2.</p>
+
+<p>Note that the fields need not be contiguous. In this example, there is a
+ 4 byte gap between the two fields. This gap represents padding which
+ does not carry useful data and need not be preserved.</p>
+
+</div>
+
<!-- _______________________________________________________________________ -->
<h4>
<a name="fpmath">'<tt>fpmath</tt>' Metadata</a>
projects / oota-llvm.git / blobdiff