Directly point debug info to the stack slot of the arugment, instead of trying to keep track of vreg in which it the arugment is copied. The LiveDebugVariable can keep track of variable's ranges.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139330 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 25 insertions, 28 deletions

diff --git a/lib/CodeGen/SelectionDAG/FastISel.cpp b/lib/CodeGen/SelectionDAG/FastISel.cpp
index 226edc64a1..fbd0c623eb 100644
--- a/lib/CodeGen/SelectionDAG/FastISel.cpp
+++ b/lib/CodeGen/SelectionDAG/FastISel.cpp
@@ -531,13 +531,10 @@ bool FastISel::SelectCall(const User *I) {
     unsigned Reg = 0;
     unsigned Offset = 0;
     if (const Argument *Arg = dyn_cast<Argument>(Address)) {
-      if (Arg->hasByValAttr()) {
-        // Byval arguments' frame index is recorded during argument lowering.
-        // Use this info directly.
-        Offset = FuncInfo.getByValArgumentFrameIndex(Arg);
-        if (Offset)
-          Reg = TRI.getFrameRegister(*FuncInfo.MF);
-      }
+      // Some arguments' frame index is recorded during argument lowering.
+      Offset = FuncInfo.getArgumentFrameIndex(Arg);
+      if (Offset)
+	Reg = TRI.getFrameRegister(*FuncInfo.MF);
     }
     if (!Reg)
       Reg = getRegForValue(Address);
diff --git a/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp b/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
index 10b251d1bf..b052740a1a 100644
--- a/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
+++ b/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
@@ -351,20 +351,18 @@ void FunctionLoweringInfo::ComputePHILiveOutRegInfo(const PHINode *PN) {
   }
 }
 
-/// setByValArgumentFrameIndex - Record frame index for the byval
+/// setArgumentFrameIndex - Record frame index for the byval
 /// argument. This overrides previous frame index entry for this argument,
 /// if any.
-void FunctionLoweringInfo::setByValArgumentFrameIndex(const Argument *A,
+void FunctionLoweringInfo::setArgumentFrameIndex(const Argument *A,
                                                       int FI) {
-  assert (A->hasByValAttr() && "Argument does not have byval attribute!");
   ByValArgFrameIndexMap[A] = FI;
 }
 
-/// getByValArgumentFrameIndex - Get frame index for the byval argument.
+/// getArgumentFrameIndex - Get frame index for the byval argument.
 /// If the argument does not have any assigned frame index then 0 is
 /// returned.
-int FunctionLoweringInfo::getByValArgumentFrameIndex(const Argument *A) {
-  assert (A->hasByValAttr() && "Argument does not have byval attribute!");
+int FunctionLoweringInfo::getArgumentFrameIndex(const Argument *A) {
   DenseMap<const Argument *, int>::iterator I =
     ByValArgFrameIndexMap.find(A);
   if (I != ByValArgFrameIndexMap.end())
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 1337754ee6..9ba1fbb7ab 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -4394,17 +4394,12 @@ SelectionDAGBuilder::EmitFuncArgumentDbgValue(const Value *V, MDNode *Variable,
     return false;
 
   unsigned Reg = 0;
-  if (Arg->hasByValAttr()) {
-    // Byval arguments' frame index is recorded during argument lowering.
-    // Use this info directly.
-    Reg = TRI->getFrameRegister(MF);
-    Offset = FuncInfo.getByValArgumentFrameIndex(Arg);
-    // If byval argument ofset is not recorded then ignore this.
-    if (!Offset)
-      Reg = 0;
-  }
+  // Some arguments' frame index is recorded during argument lowering.
+  Offset = FuncInfo.getArgumentFrameIndex(Arg);
+  if (Offset)
+      Reg = TRI->getFrameRegister(MF);
 
-  if (N.getNode()) {
+  if (!Reg && N.getNode()) {
     if (N.getOpcode() == ISD::CopyFromReg)
       Reg = cast<RegisterSDNode>(N.getOperand(1))->getReg();
     else
@@ -6733,15 +6728,22 @@ void SelectionDAGISel::LowerArguments(const BasicBlock *LLVMBB) {
     if (ArgValues.empty())
       continue;
 
-    // Note down frame index for byval arguments.
-    if (I->hasByValAttr())
-      if (FrameIndexSDNode *FI =
-          dyn_cast<FrameIndexSDNode>(ArgValues[0].getNode()))
-        FuncInfo->setByValArgumentFrameIndex(I, FI->getIndex());
+    // Note down frame index.
+    if (FrameIndexSDNode *FI =
+	dyn_cast<FrameIndexSDNode>(ArgValues[0].getNode()))
+      FuncInfo->setArgumentFrameIndex(I, FI->getIndex());
 
     SDValue Res = DAG.getMergeValues(&ArgValues[0], NumValues,
                                      SDB->getCurDebugLoc());
+
     SDB->setValue(I, Res);
+    if (!EnableFastISel && Res.getOpcode() == ISD::BUILD_PAIR) {
+      if (LoadSDNode *LNode = 
+          dyn_cast<LoadSDNode>(Res.getOperand(0).getNode()))
+        if (FrameIndexSDNode *FI =
+            dyn_cast<FrameIndexSDNode>(LNode->getBasePtr().getNode()))
+        FuncInfo->setArgumentFrameIndex(I, FI->getIndex());
+    }
 
     // If this argument is live outside of the entry block, insert a copy from
     // wherever we got it to the vreg that other BB's will reference it as.