[PATCH] D42127: [GlobalMerge] Don't merge dllexport globals

[Martin Storsjö via Phabricator via llvm-commits]

mstorsjo updated this revision to Diff 130562.
mstorsjo added a comment.

Added a testcase to show that normal globals still are merged.


https://reviews.llvm.org/D42127

Files:
  lib/CodeGen/GlobalMerge.cpp
  test/CodeGen/ARM/global-merge-dllexport.ll
  test/CodeGen/ARM/global-merge-external.ll


Index: test/CodeGen/ARM/global-merge-external.ll
===================================================================
--- test/CodeGen/ARM/global-merge-external.ll
+++ test/CodeGen/ARM/global-merge-external.ll
@@ -3,6 +3,7 @@
 ; RUN: llc < %s -mtriple=arm-eabi  -arm-global-merge -global-merge-on-external=false | FileCheck %s --check-prefixes=CHECK,CHECK-NO-MERGE
 ; RUN: llc < %s -mtriple=arm-macho -arm-global-merge                                 | FileCheck %s --check-prefixes=CHECK,CHECK-NO-MERGE
 ; RUN: llc < %s -mtriple=arm-eabi  -arm-global-merge -relocation-model=pic           | FileCheck %s --check-prefixes=CHECK,CHECK-NO-MERGE
+; RUN: llc < %s -mtriple=thumbv7-win32 -arm-global-merge                             | FileCheck %s --check-prefixes=CHECK-WIN32
 
 @x = global i32 0, align 4
 @y = global i32 0, align 4
@@ -14,6 +15,9 @@
 ;CHECK:          [[LABEL1]]:
 ;CHECK-MERGE:    .long .L_MergedGlobals
 ;CHECK-NO-MERGE: .long {{_?x}}
+;CHECK-WIN32:    f1:
+;CHECK-WIN32:    movw [[REG1:r[0-9]+]], :lower16:.L_MergedGlobals
+;CHECK-WIN32:    movt [[REG1]], :upper16:.L_MergedGlobals
   store i32 %a1, i32* @x, align 4
   store i32 %a2, i32* @y, align 4
   ret void
@@ -25,6 +29,9 @@
 ;CHECK:          [[LABEL2]]:
 ;CHECK-MERGE:    .long .L_MergedGlobals
 ;CHECK-NO-MERGE: .long {{_?y}}
+;CHECK-WIN32:    g1:
+;CHECK-WIN32:    movw [[REG2:r[0-9]+]], :lower16:.L_MergedGlobals
+;CHECK-WIN32:    movt [[REG2]], :upper16:.L_MergedGlobals
   store i32 %a1, i32* @y, align 4
   store i32 %a2, i32* @z, align 4
   ret void
@@ -35,6 +42,7 @@
 ;CHECK-MERGE:	.type	.L_MergedGlobals,%object
 ;CHECK-MERGE:	.local	.L_MergedGlobals
 ;CHECK-MERGE:	.comm	.L_MergedGlobals,12,4
+;CHECK-WIN32:	.lcomm	.L_MergedGlobals,12,4
 
 ;CHECK-MERGE:	.globl	x
 ;CHECK-MERGE: x = .L_MergedGlobals
@@ -45,3 +53,10 @@
 ;CHECK-MERGE:	.globl	z
 ;CHECK-MERGE: z = .L_MergedGlobals+8
 ;CHECK-MERGE: .size z, 4
+
+;CHECK-WIN32:	.globl	x
+;CHECK-WIN32: x = .L_MergedGlobals
+;CHECK-WIN32:	.globl	y
+;CHECK-WIN32: y = .L_MergedGlobals+4
+;CHECK-WIN32:	.globl	z
+;CHECK-WIN32: z = .L_MergedGlobals+8
Index: test/CodeGen/ARM/global-merge-dllexport.ll
===================================================================
--- /dev/null
+++ test/CodeGen/ARM/global-merge-dllexport.ll
@@ -0,0 +1,15 @@
+; RUN: llc < %s -mtriple=thumbv7-win32 -arm-global-merge | FileCheck %s
+
+ at x = global i32 0, align 4
+ at y = dllexport global i32 0, align 4
+
+define void @f1(i32 %a1, i32 %a2) {
+; CHECK: f1:
+; CHECK: movw [[REG1:r[0-9]+]], :lower16:x
+; CHECK: movt [[REG1]], :upper16:x
+  store i32 %a1, i32* @x, align 4
+  store i32 %a2, i32* @y, align 4
+  ret void
+}
+
+; CHECK-NOT: .L_MergedGlobals
Index: lib/CodeGen/GlobalMerge.cpp
===================================================================
--- lib/CodeGen/GlobalMerge.cpp
+++ lib/CodeGen/GlobalMerge.cpp
@@ -577,7 +577,8 @@
   for (auto &GV : M.globals()) {
     // Merge is safe for "normal" internal or external globals only
     if (GV.isDeclaration() || GV.isThreadLocal() ||
-        GV.hasSection() || GV.hasImplicitSection())
+        GV.hasSection() || GV.hasImplicitSection() ||
+        GV.hasDLLExportStorageClass())
       continue;
 
     // It's not safe to merge globals that may be preempted


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