Make LoadAndStorePromoter preserve debug info and create llvm.dbg.values when

promoting allocas to SSA variables. Fixes <rdar://problem/9479036>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131953 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 53 insertions, 26 deletions

diff --git a/lib/Transforms/Scalar/LICM.cpp b/lib/Transforms/Scalar/LICM.cpp
index 93de9cf002..f706cc2a55 100644
--- a/lib/Transforms/Scalar/LICM.cpp
+++ b/lib/Transforms/Scalar/LICM.cpp
@@ -602,13 +602,14 @@ namespace {
     SmallPtrSet<Value*, 4> &PointerMustAliases;
     SmallVectorImpl<BasicBlock*> &LoopExitBlocks;
     AliasSetTracker &AST;
+    DIBuilder *DIB; // Only passed to LoadAndStorePromoter.
   public:
     LoopPromoter(Value *SP,
                  const SmallVectorImpl<Instruction*> &Insts, SSAUpdater &S,
                  SmallPtrSet<Value*, 4> &PMA,
                  SmallVectorImpl<BasicBlock*> &LEB, AliasSetTracker &ast)
-      : LoadAndStorePromoter(Insts, S), SomePtr(SP), PointerMustAliases(PMA),
-        LoopExitBlocks(LEB), AST(ast) {}
+      : LoadAndStorePromoter(Insts, S, 0, DIB), SomePtr(SP),
+        PointerMustAliases(PMA), LoopExitBlocks(LEB), AST(ast) {}
     
     virtual bool isInstInList(Instruction *I,
                               const SmallVectorImpl<Instruction*> &) const {
diff --git a/lib/Transforms/Scalar/ScalarReplAggregates.cpp b/lib/Transforms/Scalar/ScalarReplAggregates.cpp
index 5f8ab517df..ebcb88c015 100644
--- a/lib/Transforms/Scalar/ScalarReplAggregates.cpp
+++ b/lib/Transforms/Scalar/ScalarReplAggregates.cpp
@@ -30,6 +30,7 @@
 #include "llvm/LLVMContext.h"
 #include "llvm/Module.h"
 #include "llvm/Pass.h"
+#include "llvm/Analysis/DIBuilder.h"
 #include "llvm/Analysis/Dominators.h"
 #include "llvm/Analysis/Loads.h"
 #include "llvm/Analysis/ValueTracking.h"
@@ -1051,8 +1052,9 @@ namespace {
 class AllocaPromoter : public LoadAndStorePromoter {
   AllocaInst *AI;
 public:
-  AllocaPromoter(const SmallVectorImpl<Instruction*> &Insts, SSAUpdater &S)
-    : LoadAndStorePromoter(Insts, S), AI(0) {}
+  AllocaPromoter(const SmallVectorImpl<Instruction*> &Insts, SSAUpdater &S,
+                 DbgDeclareInst *DD, DIBuilder *&DB)
+    : LoadAndStorePromoter(Insts, S, DD, DB), AI(0) {}
   
   void run(AllocaInst *AI, const SmallVectorImpl<Instruction*> &Insts) {
     // Remember which alloca we're promoting (for isInstInList).
@@ -1329,7 +1331,6 @@ static bool tryToMakeAllocaBePromotable(AllocaInst *AI, const TargetData *TD) {
   return true;
 }
 
-
 bool SROA::performPromotion(Function &F) {
   std::vector<AllocaInst*> Allocas;
   DominatorTree *DT = 0;
@@ -1340,6 +1341,7 @@ bool SROA::performPromotion(Function &F) {
 
   bool Changed = false;
   SmallVector<Instruction*, 64> Insts;
+  DIBuilder *DIB = 0;
   while (1) {
     Allocas.clear();
 
@@ -1363,8 +1365,9 @@ bool SROA::performPromotion(Function &F) {
         for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end();
              UI != E; ++UI)
           Insts.push_back(cast<Instruction>(*UI));
-        
-        AllocaPromoter(Insts, SSA).run(AI, Insts);
+
+        DbgDeclareInst *DDI = FindAllocaDbgDeclare(AI);
+        AllocaPromoter(Insts, SSA, DDI, DIB).run(AI, Insts);
         Insts.clear();
       }
     }
@@ -1372,6 +1375,10 @@ bool SROA::performPromotion(Function &F) {
     Changed = true;
   }
 
+  // FIXME: Is there a better way to handle the lazy initialization of DIB
+  // so that there doesn't need to be an explicit delete?
+  delete DIB;
+
   return Changed;
 }
 
diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp
index f5a8adacd5..3bdbaa5c09 100644
--- a/lib/Transforms/Utils/Local.cpp
+++ b/lib/Transforms/Utils/Local.cpp
@@ -20,6 +20,7 @@
 #include "llvm/Instructions.h"
 #include "llvm/Intrinsics.h"
 #include "llvm/IntrinsicInst.h"
+#include "llvm/Metadata.h"
 #include "llvm/Operator.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallPtrSet.h"
@@ -877,3 +878,15 @@ bool llvm::LowerDbgDeclare(Function &F) {
   }
   return true;
 }
+
+/// FindAllocaDbgDeclare - Finds the llvm.dbg.declare intrinsic describing the
+/// alloca 'V', if any.
+DbgDeclareInst *llvm::FindAllocaDbgDeclare(Value *V) {
+  if (MDNode *DebugNode = MDNode::getIfExists(V->getContext(), V))
+    for (Value::use_iterator UI = DebugNode->use_begin(),
+         E = DebugNode->use_end(); UI != E; ++UI)
+      if (DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(*UI))
+        return DDI;
+
+  return 0;
+}
diff --git a/lib/Transforms/Utils/PromoteMemoryToRegister.cpp b/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
index 50c9ae204a..a1736b931f 100644
--- a/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
+++ b/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
@@ -100,18 +100,6 @@ bool llvm::isAllocaPromotable(const AllocaInst *AI) {
   return true;
 }
 
-/// FindAllocaDbgDeclare - Finds the llvm.dbg.declare intrinsic describing the
-/// alloca 'V', if any.
-static DbgDeclareInst *FindAllocaDbgDeclare(Value *V) {
-  if (MDNode *DebugNode = MDNode::getIfExists(V->getContext(), V))
-    for (Value::use_iterator UI = DebugNode->use_begin(),
-         E = DebugNode->use_end(); UI != E; ++UI)
-      if (DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(*UI))
-        return DDI;
-
-  return 0;
-}
-
 namespace {
   struct AllocaInfo;
 
diff --git a/lib/Transforms/Utils/SSAUpdater.cpp b/lib/Transforms/Utils/SSAUpdater.cpp
index 2860c3e511..09f0a50cb0 100644
--- a/lib/Transforms/Utils/SSAUpdater.cpp
+++ b/lib/Transforms/Utils/SSAUpdater.cpp
@@ -14,7 +14,9 @@
 #define DEBUG_TYPE "ssaupdater"
 #include "llvm/Constants.h"
 #include "llvm/Instructions.h"
+#include "llvm/IntrinsicInst.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/Analysis/DIBuilder.h"
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Support/AlignOf.h"
 #include "llvm/Support/Allocator.h"
@@ -22,6 +24,7 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Transforms/Utils/Local.h"
 #include "llvm/Transforms/Utils/SSAUpdater.h"
 #include "llvm/Transforms/Utils/SSAUpdaterImpl.h"
 
@@ -355,7 +358,8 @@ Value *SSAUpdater::GetValueAtEndOfBlockInternal(BasicBlock *BB) {
 
 LoadAndStorePromoter::
 LoadAndStorePromoter(const SmallVectorImpl<Instruction*> &Insts,
-                     SSAUpdater &S, StringRef BaseName) : SSA(S) {
+                     SSAUpdater &S, DbgDeclareInst *DD, DIBuilder *&DB,
+                     StringRef BaseName) : SSA(S), DDI(DD), DIB(DB) {
   if (Insts.empty()) return;
   
   Value *SomeVal;
@@ -402,9 +406,14 @@ run(const SmallVectorImpl<Instruction*> &Insts) const {
     // single user in it, we can rewrite it trivially.
     if (BlockUses.size() == 1) {
       // If it is a store, it is a trivial def of the value in the block.
-      if (StoreInst *SI = dyn_cast<StoreInst>(User))
+      if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
+        if (DDI) {
+          if (!DIB)
+            DIB = new DIBuilder(*SI->getParent()->getParent()->getParent());
+          ConvertDebugDeclareToDebugValue(DDI, SI, *DIB);
+        }
         SSA.AddAvailableValue(BB, SI->getOperand(0));
-      else 
+      } else 
         // Otherwise it is a load, queue it to rewrite as a live-in load.
         LiveInLoads.push_back(cast<LoadInst>(User));
       BlockUses.clear();
@@ -453,12 +462,18 @@ run(const SmallVectorImpl<Instruction*> &Insts) const {
         continue;
       }
       
-      if (StoreInst *S = dyn_cast<StoreInst>(II)) {
+      if (StoreInst *SI = dyn_cast<StoreInst>(II)) {
         // If this is a store to an unrelated pointer, ignore it.
-        if (!isInstInList(S, Insts)) continue;
-        
+        if (!isInstInList(SI, Insts)) continue;
+
+        if (DDI) {
+          if (!DIB)
+            DIB = new DIBuilder(*SI->getParent()->getParent()->getParent());
+          ConvertDebugDeclareToDebugValue(DDI, SI, *DIB);
+        }
+
         // Remember that this is the active value in the block.
-        StoredValue = S->getOperand(0);
+        StoredValue = SI->getOperand(0);
       }
     }
     
@@ -513,4 +528,7 @@ run(const SmallVectorImpl<Instruction*> &Insts) const {
     instructionDeleted(User);
     User->eraseFromParent();
   }
+
+  if (DDI)
+    DDI->eraseFromParent();
 }