Change ARMGlobalMerge to keep BSS globals in separate pools.

This completes the fixes for Radar 8673120.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119566 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 17 insertions, 5 deletions

diff --git a/lib/Target/ARM/ARMGlobalMerge.cpp b/lib/Target/ARM/ARMGlobalMerge.cpp
index 72cab6462c..3f0238387a 100644
--- a/lib/Target/ARM/ARMGlobalMerge.cpp
+++ b/lib/Target/ARM/ARMGlobalMerge.cpp
@@ -65,6 +65,7 @@
 #include "llvm/Pass.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetLowering.h"
+#include "llvm/Target/TargetLoweringObjectFile.h"
 using namespace llvm;
 
 namespace {
@@ -74,7 +75,7 @@ namespace {
     const TargetLowering *TLI;
 
     bool doMerge(SmallVectorImpl<GlobalVariable*> &Globals,
-                 Module &M, bool) const;
+                 Module &M, bool isConst) const;
 
   public:
     static char ID;             // Pass identification, replacement for typeid.
@@ -161,7 +162,7 @@ bool ARMGlobalMerge::doMerge(SmallVectorImpl<GlobalVariable*> &Globals,
 
 
 bool ARMGlobalMerge::doInitialization(Module &M) {
-  SmallVector<GlobalVariable*, 16> Globals, ConstGlobals;
+  SmallVector<GlobalVariable*, 16> Globals, ConstGlobals, BSSGlobals;
   const TargetData *TD = TLI->getTargetData();
   unsigned MaxOffset = TLI->getMaximalGlobalOffset();
   bool Changed = false;
@@ -183,7 +184,10 @@ bool ARMGlobalMerge::doInitialization(Module &M) {
       continue;
 
     if (TD->getTypeAllocSize(I->getType()->getElementType()) < MaxOffset) {
-      if (I->isConstant())
+      const TargetLoweringObjectFile &TLOF = TLI->getObjFileLowering();
+      if (TLOF.getKindForGlobal(I, TLI->getTargetMachine()).isBSSLocal())
+        BSSGlobals.push_back(I);
+      else if (I->isConstant())
         ConstGlobals.push_back(I);
       else
         Globals.push_back(I);
@@ -192,10 +196,12 @@ bool ARMGlobalMerge::doInitialization(Module &M) {
 
   if (Globals.size() > 1)
     Changed |= doMerge(Globals, M, false);
+  if (BSSGlobals.size() > 1)
+    Changed |= doMerge(BSSGlobals, M, false);
+
   // FIXME: This currently breaks the EH processing due to way how the 
   // typeinfo detection works. We might want to detect the TIs and ignore 
   // them in the future.
-  
   // if (ConstGlobals.size() > 1)
   //  Changed |= doMerge(ConstGlobals, M, true);
 
diff --git a/test/CodeGen/ARM/global-merge.ll b/test/CodeGen/ARM/global-merge.ll
index e519dde33a..28bf221474 100644
--- a/test/CodeGen/ARM/global-merge.ll
+++ b/test/CodeGen/ARM/global-merge.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -march=thumb | FileCheck %s
+; RUN: llc < %s -mtriple=thumb-apple-darwin | FileCheck %s
 ; Test the ARMGlobalMerge pass.  Use -march=thumb because it has a small
 ; value for the maximum offset (127).
 
@@ -15,3 +15,9 @@
 ; When this works properly, @g3 is placed in a separate chunk of merged globals.
 ; CHECK: _MergedGlobals1:
 @g3 = internal global [30 x i32] [ i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10 ]
+
+; Global variables that can be placed in BSS should be kept together in a
+; separate pool of merged globals.
+; CHECK: _MergedGlobals2
+@g4 = internal global i32 0
+@g5 = internal global i32 0