[PATCH] D36712: Emit section information for extern variables

[Elizabeth Andrews via Phabricator via cfe-commits]

eandrews updated this revision to Diff 112172.
eandrews added a comment.

Updated the documentation to explicitly state that section information for a variable can be explicit or inferred.


https://reviews.llvm.org/D36712

Files:
  docs/LangRef.rst


Index: docs/LangRef.rst
===================================================================
--- docs/LangRef.rst
+++ docs/LangRef.rst
@@ -579,7 +579,9 @@
 case they don't have an initializer.
 
 Either global variable definitions or declarations may have an explicit section
-to be placed in and may have an optional explicit alignment specified.
+to be placed in and may have an optional explicit alignment specified. If there 
+is a mismatch between the explicit or inferred section information for the 
+variable declaration and its definition the resulting behavior is undefined. 
 
 A variable may be defined as a global ``constant``, which indicates that
 the contents of the variable will **never** be modified (enabling better
@@ -622,6 +624,12 @@
 Additionally, the global can placed in a comdat if the target has the necessary
 support.
 
+External declarations may have an explicit section specified. Section 
+information is retained in LLVM IR for targets that make use of this 
+information. Attaching section information to an external declaration is an 
+assertion that its definition is located in the specified section. If the 
+definition is located in a different section, the behavior is undefined.   
+
 By default, global initializers are optimized by assuming that global
 variables defined within the module are not modified from their
 initial values before the start of the global initializer. This is


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