From f07c0194186ad2dfb47ad6adf42a2b86c1dee26d Mon Sep 17 00:00:00 2001 From: Peter Collingbourne Date: Wed, 5 Dec 2018 00:09:36 +0000 Subject: LTO: Don't internalize available_externally globals. This breaks C and C++ semantics because it can cause the address of the global inside the module to differ from the address outside of the module. Differential Revision: https://reviews.llvm.org/D55237 Change-Id: I84f5d3860beed2953078b3bd9ea0c6d2c334e3cb git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@348321 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/LTO/LTO.cpp | 5 ++++- test/LTO/Resolution/X86/available-externally.ll | 16 ++++++++++++++++ 2 files changed, 20 insertions(+), 1 deletion(-) create mode 100644 test/LTO/Resolution/X86/available-externally.ll diff --git a/lib/LTO/LTO.cpp b/lib/LTO/LTO.cpp index 6b11f690ef3..d8e5d6ed6be 100644 --- a/lib/LTO/LTO.cpp +++ b/lib/LTO/LTO.cpp @@ -356,7 +356,10 @@ static void thinLTOInternalizeAndPromoteGUID( // Ignore local and appending linkage values since the linker // doesn't resolve them. !GlobalValue::isLocalLinkage(S->linkage()) && - !GlobalValue::isAppendingLinkage(S->linkage())) + S->linkage() != GlobalValue::AppendingLinkage && + // We can't internalize available_externally globals because this + // can break function pointer equality. + S->linkage() != GlobalValue::AvailableExternallyLinkage) S->setLinkage(GlobalValue::InternalLinkage); } } diff --git a/test/LTO/Resolution/X86/available-externally.ll b/test/LTO/Resolution/X86/available-externally.ll new file mode 100644 index 00000000000..eb17693c0a9 --- /dev/null +++ b/test/LTO/Resolution/X86/available-externally.ll @@ -0,0 +1,16 @@ +; RUN: opt -module-summary -o %t.bc %s +; RUN: llvm-lto2 run %t.bc -r %t.bc,foo,px -r %t.bc,bar, -o %t2 +; RUN: llvm-nm %t2.1 | FileCheck %s + +; CHECK: U bar + +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +define void ()* @foo() { + ret void ()* @bar +} + +define available_externally void @bar() { + ret void +} -- cgit v1.2.3