for (GlobalValue *GV : Used.used())
Used.compilerUsedErase(GV);
+ // Return whether GV is explicitly or implicitly dso_local and not replaceable
+ // by another definition in the current linkage unit.
+ auto IsModuleLocal = [](GlobalValue &GV) {
+ return !GlobalValue::isInterposableLinkage(GV.getLinkage()) &&
+ (GV.isDSOLocal() || GV.isImplicitDSOLocal());
+ };
+
for (GlobalAlias &J : llvm::make_early_inc_range(M.aliases())) {
// Aliases without names cannot be referenced outside this module.
if (!J.hasName() && !J.isDeclaration() && !J.hasLocalLinkage())
}
// If the alias can change at link time, nothing can be done - bail out.
- if (J.isInterposable())
+ if (!IsModuleLocal(J))
continue;
Constant *Aliasee = J.getAliasee();
GlobalValue *Target = dyn_cast<GlobalValue>(Aliasee->stripPointerCasts());
// We can't trivially replace the alias with the aliasee if the aliasee is
// non-trivial in some way. We also can't replace the alias with the aliasee
- // if the aliasee is interposable because aliases point to the local
- // definition.
+ // if the aliasee may be preemptible at runtime. On ELF, a non-preemptible
+ // alias can be used to access the definition as if preemption did not
+ // happen.
// TODO: Try to handle non-zero GEPs of local aliasees.
- if (!Target || Target->isInterposable())
+ if (!Target || !IsModuleLocal(*Target))
continue;
+
Target->removeDeadConstantUsers();
// Make all users of the alias use the aliasee instead.
; RUN: opt < %s -passes=globalopt -S | FileCheck %s
@foo1 = alias void (), void ()* @foo2
+;; foo2 is dso_local and non-weak. Resolved.
; CHECK: @foo1 = alias void (), void ()* @bar2
-@foo2 = alias void(), void()* @bar1
-; CHECK: @foo2 = alias void (), void ()* @bar2
+@foo2 = dso_local alias void(), void()* @bar1
+;; bar1 is dso_local and non-weak. Resolved.
+; CHECK: @foo2 = dso_local alias void (), void ()* @bar2
-@bar1 = alias void (), void ()* @bar2
-; CHECK: @bar1 = alias void (), void ()* @bar2
+@bar1 = dso_local alias void (), void ()* @bar2
+; CHECK: @bar1 = dso_local alias void (), void ()* @bar2
-@weak1 = weak alias void (), void ()* @bar2
-; CHECK: @weak1 = weak alias void (), void ()* @bar2
+@weak1 = weak dso_local alias void (), void ()* @bar2
+;; weak1 may be replaced with another definition in the linkage unit. Not resolved.
+; CHECK: @weak1 = weak dso_local alias void (), void ()* @bar2
@bar4 = private unnamed_addr constant [2 x i8*] zeroinitializer
@foo4 = weak_odr unnamed_addr alias i8*, getelementptr inbounds ([2 x i8*], [2 x i8*]* @bar4, i32 0, i32 1)
@priva = private alias void (), void ()* @bar5
; CHECK: @priva = private alias void (), void ()* @bar5
-define void @bar2() {
+define dso_local void @bar2() {
ret void
}
-; CHECK: define void @bar2()
+; CHECK: define dso_local void @bar2()
define weak void @bar5() {
ret void
define void @baz() {
entry:
call void @foo1()
-; CHECK: call void @bar2()
+;; foo1 is dso_preemptable. Not resolved.
+; CHECK: call void @foo1()
call void @foo2()
+;; foo2 is dso_local and non-weak. Resolved.
; CHECK: call void @bar2()
call void @bar1()
+;; bar1 is dso_local and non-weak. Resolved.
; CHECK: call void @bar2()
call void @weak1()
+;; weak1 is weak. Not resolved.
; CHECK: call void @weak1()
call void @priva()
+;; priva has a local linkage. Resolved.
; CHECK: call void @priva()
ret void
}
-@foo3 = alias void (), void ()* @bar3
+@foo3 = dso_local alias void (), void ()* @bar3
; CHECK-NOT: bar3
define internal void @bar3() {
ret void
}
-;CHECK: define void @foo3
+;CHECK: define dso_local void @foo3