From 5d07e0448e38d4be0cc7b1079d72b5e3644e941c Mon Sep 17 00:00:00 2001
From: Wolfgang Pieb <wolfgang_pieb@playstation.sony.com>
Date: Mon, 6 Feb 2023 13:50:37 -0800
Subject: [TLS]: Clamp the alignment of TLS global variables if required by the
 target

Adding a module flag 'MaxTLSAlign' describing the maximum alignment a global TLS
variable can have. Optimizers are prevented from increasing the alignment of such
variables beyond this threshold.

Reviewed By: probinson

Differential Revision: https://reviews.llvm.org/D140123
---
 llvm/lib/IR/Module.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

(limited to 'llvm/lib/IR/Module.cpp')

diff --git a/llvm/lib/IR/Module.cpp b/llvm/lib/IR/Module.cpp
index 49fadc9..3df1e7b 100644
--- a/llvm/lib/IR/Module.cpp
+++ b/llvm/lib/IR/Module.cpp
@@ -746,6 +746,13 @@ unsigned Module::getOverrideStackAlignment() const {
   return 0;
 }
 
+unsigned Module::getMaxTLSAlignment() const {
+  Metadata *MD = getModuleFlag("MaxTLSAlign");
+  if (auto *CI = mdconst::dyn_extract_or_null<ConstantInt>(MD))
+    return CI->getZExtValue();
+  return 0;
+}
+
 void Module::setOverrideStackAlignment(unsigned Align) {
   addModuleFlag(ModFlagBehavior::Error, "override-stack-alignment", Align);
 }
-- 
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