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-rw-r--r--llvm/docs/LangRef.html21
1 files changed, 18 insertions, 3 deletions
diff --git a/llvm/docs/LangRef.html b/llvm/docs/LangRef.html
index 83ea026c6b7..0985cbd61e6 100644
--- a/llvm/docs/LangRef.html
+++ b/llvm/docs/LangRef.html
@@ -545,11 +545,26 @@ All Global Variables and Functions have one of the following types of linkage:
</dd>
<dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
+
<dd>The semantics of this linkage follow the ELF object file model: the
symbol is weak until linked, if not linked, the symbol becomes null instead
of being an undefined reference.
</dd>
+ <dt><tt><b><a name="linkage_linkonce">linkonce_odr</a></b></tt>: </dt>
+ <dt><tt><b><a name="linkage_common">common_odr</a></b></tt>: </dt>
+ <dt><tt><b><a name="linkage_weak">weak_odr</a></b></tt>: </dt>
+ <dt><tt><b><a name="linkage_externweak">extern_weak_odr</a></b></tt>: </dt>
+ <dd>Some languages allow inequivalent globals to be merged, such as two
+ functions with different semantics. Other languages, such as <tt>C++</tt>,
+ ensure that only equivalent globals are ever merged (the "one definition
+ rule" - <tt>odr</tt>). Such languages can use the <tt>linkonce_odr</tt>,
+ <tt>common_odr</tt>, <tt>weak_odr</tt> and <tt>extern_weak_odr</tt> linkage
+ types to indicate that the global will only 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_external">externally visible</a></b></tt>:</dt>
<dd>If none of the above identifiers are used, the global is externally
@@ -592,9 +607,9 @@ external (i.e., lacking any linkage declarations), they are accessible
outside of the current module.</p>
<p>It is illegal for a function <i>declaration</i>
to have any linkage type other than "externally visible", <tt>dllimport</tt>,
-or <tt>extern_weak</tt>.</p>
-<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
-linkages.</p>
+<tt>extern_weak</tt> or <tt>extern_weak_odr</tt>.</p>
+<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
+or <tt>weak_odr</tt> linkages.</p>
</div>
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