[LangRef] Add description of toc-data global variables

[bzEq]

Add description of toc-data global variable in LLVM Language Reference.

Addressed comment in #94593 (review).

[llvmbot]

@llvm/pr-subscribers-llvm-ir

Author: Kai Luo (bzEq)

Changes

Add description of toc-data global variable in LLVM Language Reference.

Addressed comment in #94593 (review).

---

Full diff: https://github.com/llvm/llvm-project/pull/94828.diff

1 Files Affected:

• (modified) llvm/docs/LangRef.rst (+3)

diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index 9fb2c048a5c86..093f9e4c62086 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -812,6 +812,9 @@ doesn't). These kinds of structs (we may call them homogeneous scalable vector
 structs) are considered sized and can be used in loads, stores, allocas, but
 not GEPs.
 
+Globals with ``toc-data`` attribute set are stored in TOC of XCOFF. Their
+alignments are the same as that of a TOC entry.
+
 Syntax::
 
       @<GlobalVarName> = [Linkage] [PreemptionSpecifier] [Visibility]