Merging r304537:
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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
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_40@305187 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/GlobalMerge.cpp b/lib/CodeGen/GlobalMerge.cpp
index 1ea5349..be8e9aa 100644
--- a/lib/CodeGen/GlobalMerge.cpp
+++ b/lib/CodeGen/GlobalMerge.cpp
@@ -559,6 +559,10 @@
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/test/CodeGen/ARM/global-merge-external.ll b/test/CodeGen/ARM/global-merge-external.ll
index a9e0d19..03c9776 100644
--- a/test/CodeGen/ARM/global-merge-external.ll
+++ b/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
