From 1bf0f8ede6f8f2b01ae1bccb1cd7519b19465119 Mon Sep 17 00:00:00 2001
From: David Majnemer <david.majnemer@gmail.com>
Date: Mon, 20 Jul 2015 22:51:52 +0000
Subject: [MS Compat] Add support for __declspec(noalias)

The attribute '__declspec(noalias)' communicates that the function only
accesses memory pointed to by its pointer-typed arguments.

llvm-svn: 242728
---
 clang/lib/CodeGen/CGCall.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

(limited to 'clang/lib/CodeGen/CGCall.cpp')

diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 2dc94d06f32..a61f13fb9ab 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -1421,13 +1421,16 @@ void CodeGenModule::ConstructAttributeList(const CGFunctionInfo &FI,
         FuncAttrs.addAttribute(llvm::Attribute::NoReturn);
     }
 
-    // 'const' and 'pure' attribute functions are also nounwind.
+    // 'const', 'pure' and 'noalias' attributed functions are also nounwind.
     if (TargetDecl->hasAttr<ConstAttr>()) {
       FuncAttrs.addAttribute(llvm::Attribute::ReadNone);
       FuncAttrs.addAttribute(llvm::Attribute::NoUnwind);
     } else if (TargetDecl->hasAttr<PureAttr>()) {
       FuncAttrs.addAttribute(llvm::Attribute::ReadOnly);
       FuncAttrs.addAttribute(llvm::Attribute::NoUnwind);
+    } else if (TargetDecl->hasAttr<NoAliasAttr>()) {
+      FuncAttrs.addAttribute(llvm::Attribute::ArgMemOnly);
+      FuncAttrs.addAttribute(llvm::Attribute::NoUnwind);
     }
     if (TargetDecl->hasAttr<RestrictAttr>())
       RetAttrs.addAttribute(llvm::Attribute::NoAlias);
-- 
cgit v1.2.3