diff --git a/clang/test/CodeGen/asan-destructor-kind.cpp b/clang/test/CodeGen/asan-destructor-kind.cpp
--- a/clang/test/CodeGen/asan-destructor-kind.cpp
+++ b/clang/test/CodeGen/asan-destructor-kind.cpp
@@ -31,4 +31,4 @@
 }
 
 // CHECK-NONE-DTOR-NOT: llvm.global_dtor{{.+}}asan.module_dtor
-// CHECK-NONE-DTOR-NOT: define internal void @asan.module_dtor
+// CHECK-NONE-DTOR-NOT: define{{.*}}void @asan.module_dtor
diff --git a/clang/test/CodeGen/asan-no-globals-no-comdat.cpp b/clang/test/CodeGen/asan-no-globals-no-comdat.cpp
--- a/clang/test/CodeGen/asan-no-globals-no-comdat.cpp
+++ b/clang/test/CodeGen/asan-no-globals-no-comdat.cpp
@@ -5,5 +5,5 @@
 // RUN: %clang_cc1 -fsanitize=address -fsanitize-address-globals-dead-stripping -fno-integrated-as -emit-llvm -o - -triple x86_64-linux %s | FileCheck %s --check-prefix=WITHOUT-GC
 // RUN: %clang_cc1 -fsanitize=address -fdata-sections -emit-llvm -o - -triple x86_64-linux %s | FileCheck %s --check-prefix=WITHOUT-GC
 
-// WITH-GC: define internal void @asan.module_ctor() #[[#]] comdat {
+// WITH-GC: define hidden void @asan.module_ctor() #[[#]] comdat {
 // WITHOUT-GC: define internal void @asan.module_ctor() #[[#]] {
diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -2495,10 +2495,14 @@
   if (UseCtorComdat && TargetTriple.isOSBinFormatELF() && CtorComdat) {
     if (AsanCtorFunction) {
       AsanCtorFunction->setComdat(M.getOrInsertComdat(kAsanModuleCtorName));
+      AsanCtorFunction->setLinkage(GlobalValue::ExternalLinkage);
+      AsanCtorFunction->setVisibility(GlobalValue::HiddenVisibility);
       appendToGlobalCtors(M, AsanCtorFunction, Priority, AsanCtorFunction);
     }
     if (AsanDtorFunction) {
       AsanDtorFunction->setComdat(M.getOrInsertComdat(kAsanModuleDtorName));
+      AsanDtorFunction->setLinkage(GlobalValue::ExternalLinkage);
+      AsanDtorFunction->setVisibility(GlobalValue::HiddenVisibility);
       appendToGlobalDtors(M, AsanDtorFunction, Priority, AsanDtorFunction);
     }
   } else {
diff --git a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
--- a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
@@ -457,6 +457,8 @@
           [&](Function *Ctor, FunctionCallee) {
             Comdat *CtorComdat = M.getOrInsertComdat(kHwasanModuleCtorName);
             Ctor->setComdat(CtorComdat);
+            Ctor->setLinkage(GlobalValue::ExternalLinkage);
+            Ctor->setVisibility(GlobalValue::HiddenVisibility);
             appendToGlobalCtors(M, Ctor, 0, Ctor);
           });
 
diff --git a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
--- a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
+++ b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
@@ -359,6 +359,8 @@
   if (TargetTriple.supportsCOMDAT()) {
     // Use comdat to dedup CtorFunc.
     CtorFunc->setComdat(M.getOrInsertComdat(CtorName));
+    CtorFunc->setLinkage(GlobalValue::ExternalLinkage);
+    CtorFunc->setVisibility(GlobalValue::HiddenVisibility);
     appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority, CtorFunc);
   } else {
     appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority);
diff --git a/llvm/lib/Transforms/Utils/ModuleUtils.cpp b/llvm/lib/Transforms/Utils/ModuleUtils.cpp
--- a/llvm/lib/Transforms/Utils/ModuleUtils.cpp
+++ b/llvm/lib/Transforms/Utils/ModuleUtils.cpp
@@ -19,16 +19,17 @@
 #include "llvm/IR/Module.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/xxhash.h"
+#include "llvm/TargetParser/Triple.h"
 using namespace llvm;
 
 #define DEBUG_TYPE "moduleutils"
 
-static void appendToGlobalArray(StringRef ArrayName, Module &M, Function *F,
-                                int Priority, Constant *Data) {
+static void appendToGlobalStructors(StringRef ArrayName, Module &M, Function *F,
+                                    int Priority, Constant *Data) {
   IRBuilder<> IRB(M.getContext());
   FunctionType *FnTy = FunctionType::get(IRB.getVoidTy(), false);
 
-  // Get the current set of static global constructors and add the new ctor
+  // Get the current set of static global structors and add the new ctor
   // to the list.
   SmallVector<Constant *, 16> CurrentCtors;
   StructType *EltTy = StructType::get(
@@ -36,25 +37,57 @@
       IRB.getInt8PtrTy());
 
   if (GlobalVariable *GVCtor = M.getNamedGlobal(ArrayName)) {
-    if (Constant *Init = GVCtor->getInitializer()) {
-      unsigned n = Init->getNumOperands();
-      CurrentCtors.reserve(n + 1);
-      for (unsigned i = 0; i != n; ++i)
-        CurrentCtors.push_back(cast<Constant>(Init->getOperand(i)));
+    if (const Constant *Init = GVCtor->getInitializer()) {
+      CurrentCtors.reserve(Init->getNumOperands() + 1);
+      for (Value *Val : Init->operands())
+        CurrentCtors.push_back(cast<Constant>(Val));
     }
     GVCtor->eraseFromParent();
   }
 
-  // Build a 3 field global_ctor entry.  We don't take a comdat key.
-  Constant *CSVals[3];
-  CSVals[0] = IRB.getInt32(Priority);
-  CSVals[1] = F;
-  CSVals[2] = Data ? ConstantExpr::getPointerCast(Data, IRB.getInt8PtrTy())
-                   : Constant::getNullValue(IRB.getInt8PtrTy());
-  Constant *RuntimeCtorInit =
-      ConstantStruct::get(EltTy, ArrayRef(CSVals, EltTy->getNumElements()));
+  Constant *LinkedTo;
+  if (Data) {
+    // Structor will only run if Data is not discarded.
+    LinkedTo = ConstantExpr::getPointerCast(Data, IRB.getInt8PtrTy());
+
+    // Verify that on targets that support COMDAT and where Data has a COMDAT,
+    // Data has non-internal linkage, otherwise we're in for surprises with LTO:
+    // when multiple TUs are merged, LTO would use linkage to deduplicate. If
+    // linkage is set to internal linkage, we would end up with multiple
+    // identical symbols in the final binary (which without LTO, the linker
+    // would take care of due to the COMDAT, irrespective of linkage). Also
+    // verify that if linkage is external, visibility is hidden, so that DSOs
+    // don't call any other structor.
+    //
+    // We verify this here, rather than in the Verifier, since none of this is
+    // invalid, but for all users of appendToGlobalStructors() this should hold.
+    assert([&] {
+      Triple T(M.getTargetTriple());
+      if (!T.supportsCOMDAT())
+        return true;
+      if (const auto *Key = dyn_cast<GlobalValue>(Data)) {
+        if (!Key->hasComdat())
+          return true; // Nothing to check.
+        if (Key->getLinkage() == GlobalValue::ExternalLinkage) {
+          // Even with external linkage, a DSO should _not_ call any other
+          // structor but its own (which it has either way).
+          return Key->getVisibility() != GlobalValue::DefaultVisibility;
+        }
+        // Assert not internal linkage.
+        return Key->getLinkage() != GlobalValue::InternalLinkage &&
+               Key->getLinkage() != GlobalValue::PrivateLinkage;
+      }
+      return true;
+    }() && "GlobalValue used as COMDAT key for structor has incorrect linkage");
+  } else {
+    LinkedTo = Constant::getNullValue(IRB.getInt8PtrTy());
+  }
 
-  CurrentCtors.push_back(RuntimeCtorInit);
+  // Build a 3 field global_{c,d}tor entry.
+  const std::array<Constant *, 3> CSVals = {IRB.getInt32(Priority), F,
+                                            LinkedTo};
+  assert(CSVals.size() == EltTy->getNumElements());
+  CurrentCtors.push_back(ConstantStruct::get(EltTy, CSVals));
 
   // Create a new initializer.
   ArrayType *AT = ArrayType::get(EltTy, CurrentCtors.size());
@@ -67,11 +100,11 @@
 }
 
 void llvm::appendToGlobalCtors(Module &M, Function *F, int Priority, Constant *Data) {
-  appendToGlobalArray("llvm.global_ctors", M, F, Priority, Data);
+  appendToGlobalStructors("llvm.global_ctors", M, F, Priority, Data);
 }
 
 void llvm::appendToGlobalDtors(Module &M, Function *F, int Priority, Constant *Data) {
-  appendToGlobalArray("llvm.global_dtors", M, F, Priority, Data);
+  appendToGlobalStructors("llvm.global_dtors", M, F, Priority, Data);
 }
 
 static void collectUsedGlobals(GlobalVariable *GV,
diff --git a/llvm/test/CodeGen/AArch64/pacbti-llvm-generated-funcs-1.ll b/llvm/test/CodeGen/AArch64/pacbti-llvm-generated-funcs-1.ll
--- a/llvm/test/CodeGen/AArch64/pacbti-llvm-generated-funcs-1.ll
+++ b/llvm/test/CodeGen/AArch64/pacbti-llvm-generated-funcs-1.ll
@@ -14,7 +14,7 @@
 declare void @__asan_init()
 declare void @__asan_version_mismatch_check_v8()
 
-define internal void @asan.module_ctor() {
+define hidden void @asan.module_ctor() {
   call void @__asan_init()
   call void @__asan_version_mismatch_check_v8()
   ret void
diff --git a/llvm/test/DebugInfo/AArch64/asan-stack-vars.mir b/llvm/test/DebugInfo/AArch64/asan-stack-vars.mir
--- a/llvm/test/DebugInfo/AArch64/asan-stack-vars.mir
+++ b/llvm/test/DebugInfo/AArch64/asan-stack-vars.mir
@@ -252,7 +252,7 @@
 
   declare i8* @objc_autoreleaseReturnValue(i8* returned)
 
-  define internal void @asan.module_ctor() {
+  define hidden void @asan.module_ctor() {
     call void @__asan_init()
     call void @__asan_version_mismatch_check_v8()
     ret void
diff --git a/llvm/test/DebugInfo/COFF/asan-module-ctor.ll b/llvm/test/DebugInfo/COFF/asan-module-ctor.ll
--- a/llvm/test/DebugInfo/COFF/asan-module-ctor.ll
+++ b/llvm/test/DebugInfo/COFF/asan-module-ctor.ll
@@ -29,7 +29,7 @@
   ret i32 0, !dbg !10
 }
 
-define internal void @asan.module_ctor() {
+define hidden void @asan.module_ctor() {
   call void @__asan_init_v3()
   ret void
 }
diff --git a/llvm/test/DebugInfo/COFF/asan-module-without-functions.ll b/llvm/test/DebugInfo/COFF/asan-module-without-functions.ll
--- a/llvm/test/DebugInfo/COFF/asan-module-without-functions.ll
+++ b/llvm/test/DebugInfo/COFF/asan-module-without-functions.ll
@@ -20,7 +20,7 @@
 @0 = internal global [1 x { i32, i32, i32, i32, i32, i32 }] [{ i32, i32, i32, i32, i32, i32 } { i32 ptrtoint (ptr @c to i32), i32 1, i32 64, i32 ptrtoint (ptr @___asan_gen_1 to i32), i32 ptrtoint (ptr @___asan_gen_ to i32), i32 0 }]
 @llvm.global_dtors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 1, ptr @asan.module_dtor, ptr null }]
 
-define internal void @asan.module_ctor() {
+define hidden void @asan.module_ctor() {
   call void @__asan_init_v3()
   call void @__asan_register_globals(i32 ptrtoint (ptr @0 to i32), i32 1)
   ret void
@@ -36,7 +36,7 @@
 
 declare void @__asan_unregister_globals(i32, i32)
 
-define internal void @asan.module_dtor() {
+define hidden void @asan.module_dtor() {
   call void @__asan_unregister_globals(i32 ptrtoint (ptr @0 to i32), i32 1)
   ret void
 }
diff --git a/llvm/test/DebugInfo/Generic/incorrect-variable-debugloc.ll b/llvm/test/DebugInfo/Generic/incorrect-variable-debugloc.ll
--- a/llvm/test/DebugInfo/Generic/incorrect-variable-debugloc.ll
+++ b/llvm/test/DebugInfo/Generic/incorrect-variable-debugloc.ll
@@ -198,7 +198,7 @@
 ; Function Attrs: nounwind readnone
 declare void @llvm.dbg.value(metadata, metadata, metadata) #3
 
-define internal void @asan.module_ctor() {
+define hidden void @asan.module_ctor() {
   tail call void @__asan_init_v3()
   ret void
 }
diff --git a/llvm/test/DebugInfo/X86/dbg_value_direct.ll b/llvm/test/DebugInfo/X86/dbg_value_direct.ll
--- a/llvm/test/DebugInfo/X86/dbg_value_direct.ll
+++ b/llvm/test/DebugInfo/X86/dbg_value_direct.ll
@@ -89,7 +89,7 @@
 
 declare void @_ZN1AC1Ev(ptr) #2
 
-define internal void @asan.module_ctor()  "stack-protector-buffer-size"="1" {
+define hidden void @asan.module_ctor()  "stack-protector-buffer-size"="1" {
   call void @__asan_init_v3()
   %1 = load volatile i64, ptr @__asan_mapping_offset
   %2 = load volatile i64, ptr @__asan_mapping_scale
diff --git a/llvm/test/Instrumentation/AddressSanitizer/AMDGPU/asan_do_not_instrument_lds.ll b/llvm/test/Instrumentation/AddressSanitizer/AMDGPU/asan_do_not_instrument_lds.ll
--- a/llvm/test/Instrumentation/AddressSanitizer/AMDGPU/asan_do_not_instrument_lds.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/AMDGPU/asan_do_not_instrument_lds.ll
@@ -24,4 +24,4 @@
   ret void
 }
 
-; CHECK-LABEL: define internal void @asan.module_ctor()
+; CHECK-LABEL: define hidden void @asan.module_ctor()
diff --git a/llvm/test/Instrumentation/AddressSanitizer/basic.ll b/llvm/test/Instrumentation/AddressSanitizer/basic.ll
--- a/llvm/test/Instrumentation/AddressSanitizer/basic.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/basic.ll
@@ -189,7 +189,7 @@
 
 ;; ctor/dtor have the nounwind attribute. See uwtable.ll, they additionally have
 ;; the uwtable attribute with the module flag "uwtable".
-; CHECK: define internal void @asan.module_ctor() #[[#ATTR:]] {{(comdat )?}}{
+; CHECK: define hidden void @asan.module_ctor() #[[#ATTR:]] {{(comdat )?}}{
 ; CHECK: call void @__asan_init()
 
 ; CHECK: attributes #[[#ATTR]] = { nounwind }
diff --git a/llvm/test/Instrumentation/AddressSanitizer/instrument_global.ll b/llvm/test/Instrumentation/AddressSanitizer/instrument_global.ll
--- a/llvm/test/Instrumentation/AddressSanitizer/instrument_global.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/instrument_global.ll
@@ -69,12 +69,12 @@
 ; CHECK: ret i32
 }
 
-; CHECK-LABEL: define internal void @asan.module_ctor
+; CHECK-LABEL: define hidden void @asan.module_ctor
 ; CHECK-NOT: ret
 ; CHECK: call void @__asan_register_elf_globals
 ; CHECK: ret
 
-; CHECK-LABEL: define internal void @asan.module_dtor
+; CHECK-LABEL: define hidden void @asan.module_dtor
 ; CHECK-NOT: ret
 ; CHECK: call void @__asan_unregister_elf_globals
 ; CHECK: ret
diff --git a/llvm/test/Instrumentation/AddressSanitizer/kcfi-offset.ll b/llvm/test/Instrumentation/AddressSanitizer/kcfi-offset.ll
--- a/llvm/test/Instrumentation/AddressSanitizer/kcfi-offset.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/kcfi-offset.ll
@@ -4,7 +4,7 @@
 
 ; CHECK: @llvm.global_ctors = {{.*}}{ i32 1, ptr @asan.module_ctor, ptr @asan.module_ctor }
 
-; CHECK: define internal void @asan.module_ctor()
+; CHECK: define hidden void @asan.module_ctor()
 ; CHECK-SAME: #[[#ATTR:]]
 ; CHECK-SAME: !kcfi_type
 
diff --git a/llvm/test/Instrumentation/AddressSanitizer/kcfi.ll b/llvm/test/Instrumentation/AddressSanitizer/kcfi.ll
--- a/llvm/test/Instrumentation/AddressSanitizer/kcfi.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/kcfi.ll
@@ -4,7 +4,7 @@
 
 ; CHECK: @llvm.global_ctors = {{.*}}{ i32 1, ptr @asan.module_ctor, ptr @asan.module_ctor }
 
-; CHECK: define internal void @asan.module_ctor()
+; CHECK: define hidden void @asan.module_ctor()
 ; CHECK-SAME: !kcfi_type
 
 !llvm.module.flags = !{!0}
diff --git a/llvm/test/Instrumentation/AddressSanitizer/module-flags.ll b/llvm/test/Instrumentation/AddressSanitizer/module-flags.ll
--- a/llvm/test/Instrumentation/AddressSanitizer/module-flags.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/module-flags.ll
@@ -19,6 +19,6 @@
 !1 = !{i32 7, !"frame-pointer", i32 2}
 
 ;; Set the uwtable attribute on ctor/dtor.
-; CHECK: define internal void @asan.module_ctor() #[[#ATTR:]]
-; CHECK: define internal void @asan.module_dtor() #[[#ATTR]]
+; CHECK: define hidden void @asan.module_ctor() #[[#ATTR:]]
+; CHECK: define hidden void @asan.module_dtor() #[[#ATTR]]
 ; CHECK: attributes #[[#ATTR]] = { nounwind uwtable "frame-pointer"="all" }
diff --git a/llvm/test/Instrumentation/AddressSanitizer/no-global-ctors.ll b/llvm/test/Instrumentation/AddressSanitizer/no-global-ctors.ll
--- a/llvm/test/Instrumentation/AddressSanitizer/no-global-ctors.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/no-global-ctors.ll
@@ -9,7 +9,7 @@
 ; RUN:   -asan-constructor-kind=none -S | \
 ; RUN:   FileCheck %s
 ; CHECK-NOT: llvm.global_ctor{{.+}}asan.module_ctor
-; CHECK-NOT: define internal void @asan.module_ctor
+; CHECK-NOT: define{{.*}}void @asan.module_ctor
 
 target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-macosx11.0.0"
diff --git a/llvm/test/Instrumentation/AddressSanitizer/no-globals.ll b/llvm/test/Instrumentation/AddressSanitizer/no-globals.ll
--- a/llvm/test/Instrumentation/AddressSanitizer/no-globals.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/no-globals.ll
@@ -8,5 +8,5 @@
 ; CHECK-NOT: @llvm.global_dtors
 ; CHECK: @llvm.global_ctors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 1, ptr @asan.module_ctor, ptr @asan.module_ctor }]
 ; CHECK-NOT: @llvm.global_dtors
-; CHECK: define internal void @asan.module_ctor() #[[#]] comdat
+; CHECK: define hidden void @asan.module_ctor() #[[#]] comdat
 ; CHECK-NOT: @llvm.global_dtors
diff --git a/llvm/test/Instrumentation/AddressSanitizer/no_global_dtors.ll b/llvm/test/Instrumentation/AddressSanitizer/no_global_dtors.ll
--- a/llvm/test/Instrumentation/AddressSanitizer/no_global_dtors.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/no_global_dtors.ll
@@ -9,7 +9,7 @@
 ; RUN:   -asan-destructor-kind=none -S | \
 ; RUN:   FileCheck %s
 ; CHECK-NOT: llvm.global_dtor{{.+}}asan.module_dtor
-; CHECK-NOT: define internal void @asan.module_dtor
+; CHECK-NOT: define{{.*}}void @asan.module_dtor
 
 target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-macosx11.0.0"
diff --git a/llvm/test/Instrumentation/AddressSanitizer/program-addrspace.ll b/llvm/test/Instrumentation/AddressSanitizer/program-addrspace.ll
--- a/llvm/test/Instrumentation/AddressSanitizer/program-addrspace.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/program-addrspace.ll
@@ -8,7 +8,7 @@
 ; CHECK: @llvm.used = appending global [1 x ptr] [ptr addrspacecast (ptr addrspace(1) @asan.module_ctor to ptr)], section "llvm.metadata"
 ; CHECK: @llvm.global_ctors = appending global [1 x { i32, ptr addrspace(1), ptr }] [{ i32, ptr addrspace(1), ptr } { i32 1, ptr addrspace(1) @asan.module_ctor, ptr addrspacecast (ptr addrspace(1) @asan.module_ctor to ptr) }]
 
-; CHECK: define internal void @asan.module_ctor() addrspace(1) #0 comdat {
+; CHECK: define hidden void @asan.module_ctor() addrspace(1) #0 comdat {
 
 target datalayout = "P1"
 
diff --git a/llvm/test/Instrumentation/AddressSanitizer/version-mismatch-check.ll b/llvm/test/Instrumentation/AddressSanitizer/version-mismatch-check.ll
--- a/llvm/test/Instrumentation/AddressSanitizer/version-mismatch-check.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/version-mismatch-check.ll
@@ -7,6 +7,6 @@
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
 target triple = "x86_64-unknown-linux-gnu"
 
-; CHECK-LABEL: define internal void @asan.module_ctor()
+; CHECK-LABEL: define hidden void @asan.module_ctor()
 ; CHECK:         call void @__asan_version_mismatch_check_
 ; NOGUARD-NOT:   call void @__asan_version_mismatch_check_
diff --git a/llvm/test/Instrumentation/HWAddressSanitizer/RISCV/basic.ll b/llvm/test/Instrumentation/HWAddressSanitizer/RISCV/basic.ll
--- a/llvm/test/Instrumentation/HWAddressSanitizer/RISCV/basic.ll
+++ b/llvm/test/Instrumentation/HWAddressSanitizer/RISCV/basic.ll
@@ -393,7 +393,7 @@
 
 ; CHECK: declare void @__hwasan_init()
 
-; CHECK:      define internal void @hwasan.module_ctor() #[[#ATTR:]] comdat {
+; CHECK:      define hidden void @hwasan.module_ctor() #[[#ATTR:]] comdat {
 ; CHECK-NEXT:   call void @__hwasan_init()
 ; CHECK-NEXT:   ret void
 ; CHECK-NEXT: }
diff --git a/llvm/test/Instrumentation/HWAddressSanitizer/RISCV/with-calls.ll b/llvm/test/Instrumentation/HWAddressSanitizer/RISCV/with-calls.ll
--- a/llvm/test/Instrumentation/HWAddressSanitizer/RISCV/with-calls.ll
+++ b/llvm/test/Instrumentation/HWAddressSanitizer/RISCV/with-calls.ll
@@ -197,7 +197,7 @@
 
 ; CHECK: declare void @__hwasan_init()
 
-; CHECK:      define internal void @hwasan.module_ctor() #[[#]] comdat {
+; CHECK:      define hidden void @hwasan.module_ctor() #[[#]] comdat {
 ; CHECK-NEXT:   call void @__hwasan_init()
 ; CHECK-NEXT:   ret void
 ; CHECK-NEXT: }
diff --git a/llvm/test/Instrumentation/HWAddressSanitizer/basic.ll b/llvm/test/Instrumentation/HWAddressSanitizer/basic.ll
--- a/llvm/test/Instrumentation/HWAddressSanitizer/basic.ll
+++ b/llvm/test/Instrumentation/HWAddressSanitizer/basic.ll
@@ -393,7 +393,7 @@
 
 ; CHECK: declare void @__hwasan_init()
 
-; CHECK:      define internal void @hwasan.module_ctor() #[[#ATTR:]] comdat {
+; CHECK:      define hidden void @hwasan.module_ctor() #[[#ATTR:]] comdat {
 ; CHECK-NEXT:   call void @__hwasan_init()
 ; CHECK-NEXT:   ret void
 ; CHECK-NEXT: }
diff --git a/llvm/test/Instrumentation/HWAddressSanitizer/with-calls.ll b/llvm/test/Instrumentation/HWAddressSanitizer/with-calls.ll
--- a/llvm/test/Instrumentation/HWAddressSanitizer/with-calls.ll
+++ b/llvm/test/Instrumentation/HWAddressSanitizer/with-calls.ll
@@ -197,7 +197,7 @@
 
 ; CHECK: declare void @__hwasan_init()
 
-; CHECK:      define internal void @hwasan.module_ctor() #[[#]] comdat {
+; CHECK:      define hidden void @hwasan.module_ctor() #[[#]] comdat {
 ; CHECK-NEXT:   call void @__hwasan_init()
 ; CHECK-NEXT:   ret void
 ; CHECK-NEXT: }
diff --git a/llvm/test/Instrumentation/SanitizerCoverage/pc-table.ll b/llvm/test/Instrumentation/SanitizerCoverage/pc-table.ll
--- a/llvm/test/Instrumentation/SanitizerCoverage/pc-table.ll
+++ b/llvm/test/Instrumentation/SanitizerCoverage/pc-table.ll
@@ -21,6 +21,6 @@
 ; CHECK: private constant [6 x ptr] [ptr @foo, ptr inttoptr (i64 1 to ptr), ptr blockaddress(@foo, %entry.if.end_crit_edge), ptr null, ptr blockaddress(@foo, %if.then), ptr null], section "__sancov_pcs", comdat($foo), align 8
 ; CHECK:      @__start___sancov_pcs = extern_weak hidden global i64
 ; CHECK-NEXT: @__stop___sancov_pcs = extern_weak hidden global i64
-; CHECK: define internal void @sancov.module_ctor
+; CHECK: define hidden void @sancov.module_ctor
 ; CHECK: call void @__sanitizer_cov
 ; CHECK: call void @__sanitizer_cov_pcs_init
diff --git a/llvm/test/Instrumentation/SanitizerCoverage/trace-pc-guard-inline-8bit-counters.ll b/llvm/test/Instrumentation/SanitizerCoverage/trace-pc-guard-inline-8bit-counters.ll
--- a/llvm/test/Instrumentation/SanitizerCoverage/trace-pc-guard-inline-8bit-counters.ll
+++ b/llvm/test/Instrumentation/SanitizerCoverage/trace-pc-guard-inline-8bit-counters.ll
@@ -3,8 +3,8 @@
 ; Module ctors should have stable names across modules, not something like
 ; @sancov.module_ctor.3 that may cause duplicate ctors after linked together.
 
-; CHECK: define internal void @sancov.module_ctor_trace_pc_guard() #[[#]] comdat {
-; CHECK: define internal void @sancov.module_ctor_8bit_counters() #[[#]] comdat {
+; CHECK: define hidden void @sancov.module_ctor_trace_pc_guard() #[[#]] comdat {
+; CHECK: define hidden void @sancov.module_ctor_8bit_counters() #[[#]] comdat {
 
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
 target triple = "x86_64-unknown-linux-gnu"
diff --git a/llvm/test/Instrumentation/SanitizerCoverage/trace-pc-guard-inline-bool-flag.ll b/llvm/test/Instrumentation/SanitizerCoverage/trace-pc-guard-inline-bool-flag.ll
--- a/llvm/test/Instrumentation/SanitizerCoverage/trace-pc-guard-inline-bool-flag.ll
+++ b/llvm/test/Instrumentation/SanitizerCoverage/trace-pc-guard-inline-bool-flag.ll
@@ -2,9 +2,11 @@
 
 ; Module ctors should have stable names across modules, not something like
 ; @sancov.module_ctor.3 that may cause duplicate ctors after linked together.
+; They should also have external linkage, so that LTO doesn't end up producing
+; duplicate ctors either.
 
-; CHECK: define internal void @sancov.module_ctor_trace_pc_guard() #[[#]] comdat {
-; CHECK: define internal void @sancov.module_ctor_bool_flag() #[[#]] comdat {
+; CHECK: define hidden void @sancov.module_ctor_trace_pc_guard() #[[#]] comdat {
+; CHECK: define hidden void @sancov.module_ctor_bool_flag() #[[#]] comdat {
 
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
 target triple = "x86_64-unknown-linux-gnu"
diff --git a/llvm/test/Instrumentation/SanitizerCoverage/trace-pc-guard.ll b/llvm/test/Instrumentation/SanitizerCoverage/trace-pc-guard.ll
--- a/llvm/test/Instrumentation/SanitizerCoverage/trace-pc-guard.ll
+++ b/llvm/test/Instrumentation/SanitizerCoverage/trace-pc-guard.ll
@@ -73,7 +73,7 @@
   ret void
 }
 
-; ELF-LABEL: define internal void @sancov.module_ctor_trace_pc_guard() #2 comdat {
+; ELF-LABEL: define hidden void @sancov.module_ctor_trace_pc_guard() #2 comdat {
 ; MACHO-LABEL: define internal void @sancov.module_ctor_trace_pc_guard() #2 {
 
 ; CHECK: attributes #2 = { nounwind }