[PATCH] D43029: Fix PR36268

[Rafael Avila de Espindola via Phabricator via llvm-commits]

espindola created this revision.
espindola added reviewers: rnk, hans, thakis.

The issue is that clang was first creating a extern_weak hidden GV and then changing the linkage to external.

Once we know it is not extern_weak we know it must be dso_local.

This patch refactors the code that sets the implicit dso_local to a helper private function that is used every time we change the linkage or visibility.


https://reviews.llvm.org/D43029

Files:
  clang/test/CodeGenObjC/availability-dso-local.m
  llvm/include/llvm/IR/GlobalValue.h


Index: llvm/include/llvm/IR/GlobalValue.h
===================================================================
--- llvm/include/llvm/IR/GlobalValue.h
+++ llvm/include/llvm/IR/GlobalValue.h
@@ -112,6 +112,12 @@
 private:
   friend class Constant;
 
+  void maybeSetDsoLocal() {
+    if (hasLocalLinkage() ||
+        (!hasDefaultVisibility() && !hasExternalWeakLinkage()))
+      setDSOLocal(true);
+  }
+
   // Give subclasses access to what otherwise would be wasted padding.
   // (17 + 4 + 2 + 2 + 2 + 3 + 1 + 1) == 32.
   unsigned SubClassData : GlobalValueSubClassDataBits;
@@ -233,8 +239,7 @@
     assert((!hasLocalLinkage() || V == DefaultVisibility) &&
            "local linkage requires default visibility");
     Visibility = V;
-    if (!hasExternalWeakLinkage() && V != DefaultVisibility)
-      setDSOLocal(true);
+    maybeSetDsoLocal();
   }
 
   /// If the value is "Thread Local", its value isn't shared by the threads.
@@ -437,11 +442,10 @@
   }
 
   void setLinkage(LinkageTypes LT) {
-    if (isLocalLinkage(LT)) {
+    if (isLocalLinkage(LT))
       Visibility = DefaultVisibility;
-      setDSOLocal(true);
-    }
     Linkage = LT;
+    maybeSetDsoLocal();
   }
   LinkageTypes getLinkage() const { return LinkageTypes(Linkage); }
 
Index: clang/test/CodeGenObjC/availability-dso-local.m
===================================================================
--- /dev/null
+++ clang/test/CodeGenObjC/availability-dso-local.m
@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -triple thumbv7-apple-ios10.0.0 -emit-llvm -fvisibility hidden -w %s -o - | FileCheck %s
+
+// CHECK: @"OBJC_CLASS_$_a" = hidden global %struct._class_t
+
+__attribute__((availability(ios, introduced = 11.0))) @interface a @end
+    @implementation a @end


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