Commit 425198bf authored by Michael Spang's avatar Michael Spang Committed by Hans Wennborg
Browse files

[GlobalMerge] Preserve symbol visibility when merging globals 

Symbols created for merged external global variables have default
visibility. This can break programs when compiling with -Oz
-fvisibility=hidden as symbols that should be hidden will be exported at
link time.

Differential Revision: https://reviews.llvm.org/D73235

(cherry picked from commit a2fb2c0d)
parent 81d73c6d

llvm/lib/CodeGen/GlobalMerge.cpp

+2 −0
Original line number Diff line number Diff line
@@ -524,6 +524,7 @@ bool GlobalMerge::doMerge(const SmallVectorImpl<GlobalVariable *> &Globals, 
    for (ssize_t k = i, idx = 0; k != j; k = GlobalSet.find_next(k), ++idx) {

      GlobalValue::LinkageTypes Linkage = Globals[k]->getLinkage();

      std::string Name = Globals[k]->getName();

      GlobalValue::VisibilityTypes Visibility = Globals[k]->getVisibility();

      GlobalValue::DLLStorageClassTypes DLLStorage =

          Globals[k]->getDLLStorageClass();
@@ -549,6 +550,7 @@ bool GlobalMerge::doMerge(const SmallVectorImpl<GlobalVariable *> &Globals, 
      if (Linkage != GlobalValue::InternalLinkage || !IsMachO) {

        GlobalAlias *GA = GlobalAlias::create(Tys[StructIdxs[idx]], AddrSpace,

                                              Linkage, Name, GEP, &M);

        GA->setVisibility(Visibility);

        GA->setDLLStorageClass(DLLStorage);

      }

llvm/test/CodeGen/AArch64/global-merge-hidden-minsize.ll

0 → 100644
+26 −0
Original line number Diff line number Diff line 
; RUN: llc %s -mtriple=arm-none-linux-gnu -o - | FileCheck %s

; RUN: llc %s -mtriple=aarch64-none-linux-gnu -o - | FileCheck %s



@x = hidden global i32 0, align 4

@y = hidden global i32 0, align 4



define hidden void @f() #0 {

  store i32 0, i32* @x, align 4

  store i32 0, i32* @y, align 4

  ret void

}



attributes #0 = { minsize optsize }



; CHECK: .local .L_MergedGlobals

; CHECK: .comm .L_MergedGlobals,8,4



; CHECK: .globl x

; CHECK: .hidden x

; CHECK: .set x, .L_MergedGlobals

; CHECK: .size x, 4



; CHECK: .globl y

; CHECK: .hidden y

; CHECK: .set y, .L_MergedGlobals+4

; CHECK: .size y, 4