First step in fixing PR8927:

Add a unnamed_addr bit to global variables and functions. This will be used
to indicate that the address is not significant and therefore the constant
or function can be merged with others.

If an optimization pass can show that an address is not used, it can set this.

Examples of things that can have this set by the FE are globals created to
hold string literals and C++ constructors.

Adding unnamed_addr to a non-const global should have no effect unless
an optimization can transform that global into a constant.

Aliases are not allowed to have unnamed_addr since I couldn't figure
out any use for it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123063 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 0 deletions

diff --git a/docs/BitCodeFormat.html b/docs/BitCodeFormat.html
index d8ddc2b6b2..0b8747c261 100644
--- a/docs/BitCodeFormat.html
+++ b/docs/BitCodeFormat.html
@@ -922,6 +922,9 @@ encoding of the visibility of this variable:
 <li><i>threadlocal</i>: If present and non-zero, indicates that the variable
 is <tt>thread_local</tt></li>
 
+<li><i>unnamed_addr</i>: If present and non-zero, indicates that the variable
+has <tt>unnamed_addr<tt></li>
+
 </ul>
 </div>
 
@@ -975,6 +978,10 @@ entries.</li>
 <li><i>gc</i>: If present and nonzero, the 1-based garbage collector
 index in the table of
 <a href="#MODULE_CODE_GCNAME">MODULE_CODE_GCNAME</a> entries.</li>
+
+<li><i>unnamed_addr</i>: If present and non-zero, indicates that the function
+has <tt>unnamed_addr<tt></li>
+
 </ul>
 </div>