From fcf5f77b3ec107aec5a49690a01dc2098dac8d2e Mon Sep 17 00:00:00 2001
From: Tom Stellard <tstellar@redhat.com>
Date: Mon, 12 Jun 2017 14:17:05 +0000
Subject: [PATCH] Merging r304537:
------------------------------------------------------------------------
r304537 | john.brawn | 2017-06-02 06:24:14 -0400 (Fri, 02 Jun 2017) | 9 lines
[GlobalMerge] Don't merge globals that may be preempted
When a global may be preempted it needs to be accessed directly, instead of
indirectly through a MergedGlobals symbol, for the preemption to work.
This fixes PR33136.
Differential Revision: https://reviews.llvm.org/D33727
------------------------------------------------------------------------
llvm-svn: 305187
---
llvm/lib/CodeGen/GlobalMerge.cpp | 4 ++++
llvm/test/CodeGen/ARM/global-merge-external.ll | 1 +
2 files changed, 5 insertions(+)
diff --git a/llvm/lib/CodeGen/GlobalMerge.cpp b/llvm/lib/CodeGen/GlobalMerge.cpp
index 1ea534939948..be8e9aa88a41 100644
--- a/llvm/lib/CodeGen/GlobalMerge.cpp
+++ b/llvm/lib/CodeGen/GlobalMerge.cpp
@@ -559,6 +559,10 @@ bool GlobalMerge::doInitialization(Module &M) {
if (GV.isDeclaration() || GV.isThreadLocal() || GV.hasSection())
continue;
+ // It's not safe to merge globals that may be preempted
+ if (TM && !TM->shouldAssumeDSOLocal(M, &GV))
+ continue;
+
if (!(MergeExternalGlobals && GV.hasExternalLinkage()) &&
!GV.hasInternalLinkage())
continue;
diff --git a/llvm/test/CodeGen/ARM/global-merge-external.ll b/llvm/test/CodeGen/ARM/global-merge-external.ll
index a9e0d199705a..03c977614320 100644
--- a/llvm/test/CodeGen/ARM/global-merge-external.ll
+++ b/llvm/test/CodeGen/ARM/global-merge-external.ll
@@ -2,6 +2,7 @@
; RUN: llc < %s -mtriple=arm-eabi -arm-global-merge -global-merge-on-external=true | FileCheck %s --check-prefix=CHECK-MERGE
; RUN: llc < %s -mtriple=arm-eabi -arm-global-merge -global-merge-on-external=false | FileCheck %s --check-prefix=CHECK-NO-MERGE
; RUN: llc < %s -mtriple=arm-macho -arm-global-merge | FileCheck %s --check-prefix=CHECK-NO-MERGE
+; RUN: llc < %s -mtriple=arm-eabi -arm-global-merge -relocation-model=pic | FileCheck %s --check-prefix=CHECK-NO-MERGE
@x = global i32 0, align 4
@y = global i32 0, align 4
--
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