Fix bug in lowering of DYNAMIC_STACKALLOC nodes. The correct offset of the

dynamically allocated stack area was not set.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132758 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 139 insertions, 37 deletions

diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index 2e9e2a150a..77ef829450 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -59,6 +59,7 @@ const char *MipsTargetLowering::getTargetNodeName(unsigned Opcode) const {
   case MipsISD::BuildPairF64:      return "MipsISD::BuildPairF64";
   case MipsISD::ExtractElementF64: return "MipsISD::ExtractElementF64";
   case MipsISD::WrapperPIC:        return "MipsISD::WrapperPIC";
+  case MipsISD::DynAlloc:          return "MipsISD::DynAlloc";
   default:                         return NULL;
   }
 }
@@ -1189,6 +1190,9 @@ MipsTargetLowering::EmitAtomicCmpSwapPartword(MachineInstr *MI,
 SDValue MipsTargetLowering::
 LowerDYNAMIC_STACKALLOC(SDValue Op, SelectionDAG &DAG) const
 {
+  MachineFunction &MF = DAG.getMachineFunction();
+  MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
+
   unsigned StackAlignment =
     getTargetMachine().getFrameLowering()->getStackAlignment();
   assert(StackAlignment >=
@@ -1211,24 +1215,14 @@ LowerDYNAMIC_STACKALLOC(SDValue Op, SelectionDAG &DAG) const
   // must be placed in the stack pointer register.
   Chain = DAG.getCopyToReg(StackPointer.getValue(1), dl, Mips::SP, Sub,
                            SDValue());
-  // Retrieve updated $sp. There is a glue input to prevent instructions that
-  // clobber $sp from being inserted between copytoreg and copyfromreg.
-  SDValue NewSP = DAG.getCopyFromReg(Chain, dl, Mips::SP, MVT::i32,
-                                     Chain.getValue(1));
-  
-  // The stack space reserved by alloca is located right above the argument
-  // area. It is aligned on a boundary that is a multiple of StackAlignment.
-  MachineFunction &MF = DAG.getMachineFunction();
-  MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
-  unsigned SPOffset = (MipsFI->getMaxCallFrameSize() + StackAlignment - 1) /
-                      StackAlignment * StackAlignment;
-  SDValue AllocPtr = DAG.getNode(ISD::ADD, dl, MVT::i32, NewSP,
-                                 DAG.getConstant(SPOffset, MVT::i32));
 
   // This node always has two return values: a new stack pointer
   // value and a chain
-  SDValue Ops[2] = { AllocPtr, NewSP.getValue(1) };
-  return DAG.getMergeValues(Ops, 2, dl);
+  SDVTList VTLs = DAG.getVTList(MVT::i32, MVT::Other);
+  SDValue Ptr = DAG.getFrameIndex(MipsFI->getDynAllocFI(), getPointerTy());
+  SDValue Ops[] = { Chain, Ptr, Chain.getValue(1) };
+
+  return DAG.getNode(MipsISD::DynAlloc, dl, VTLs, Ops, 3);
 }
 
 SDValue MipsTargetLowering::
@@ -1770,6 +1764,10 @@ MipsTargetLowering::LowerCall(SDValue Chain, SDValue Callee,
   if (IsPIC && !MipsFI->getGPFI())
     MipsFI->setGPFI(MFI->CreateFixedObject(4, 0, true));
 
+  // Get the frame index of the stack frame object that points to the location
+  // of dynamically allocated area on the stack.
+  int DynAllocFI = MipsFI->getDynAllocFI();
+    
   // Update size of the maximum argument space.
   // For O32, a minimum of four words (16 bytes) of argument space is
   // allocated.
@@ -1781,14 +1779,17 @@ MipsTargetLowering::LowerCall(SDValue Chain, SDValue Callee,
   if (MaxCallFrameSize < NextStackOffset) {
     MipsFI->setMaxCallFrameSize(NextStackOffset);
 
-    if (IsPIC) {    
-      // $gp restore slot must be aligned.
-      unsigned StackAlignment = TFL->getStackAlignment();
-      NextStackOffset = (NextStackOffset + StackAlignment - 1) / 
-                        StackAlignment * StackAlignment;
-      int GPFI = MipsFI->getGPFI();
-      MFI->setObjectOffset(GPFI, NextStackOffset);
-    }
+    // Set the offsets relative to $sp of the $gp restore slot and dynamically
+    // allocated stack space. These offsets must be aligned to a boundary
+    // determined by the stack alignment of the ABI. 
+    unsigned StackAlignment = TFL->getStackAlignment();
+    NextStackOffset = (NextStackOffset + StackAlignment - 1) / 
+                      StackAlignment * StackAlignment;
+
+    if (IsPIC)
+      MFI->setObjectOffset(MipsFI->getGPFI(), NextStackOffset);
+    
+    MFI->setObjectOffset(DynAllocFI, NextStackOffset);
   }
 
   // With EABI is it possible to have 16 args on registers.
diff --git a/lib/Target/Mips/MipsISelLowering.h b/lib/Target/Mips/MipsISelLowering.h
index fbcedfddf9..b7b85fd8f9 100644
--- a/lib/Target/Mips/MipsISelLowering.h
+++ b/lib/Target/Mips/MipsISelLowering.h
@@ -79,7 +79,9 @@ namespace llvm {
       BuildPairF64,
       ExtractElementF64,
 
-      WrapperPIC
+      WrapperPIC,
+
+      DynAlloc
     };
   }
 
diff --git a/lib/Target/Mips/MipsInstrInfo.td b/lib/Target/Mips/MipsInstrInfo.td
index 329a002667..06513220b6 100644
--- a/lib/Target/Mips/MipsInstrInfo.td
+++ b/lib/Target/Mips/MipsInstrInfo.td
@@ -39,6 +39,9 @@ def SDT_MipsDivRem       : SDTypeProfile<0, 2,
 
 def SDT_MipsThreadPointer : SDTypeProfile<1, 0, [SDTCisPtrTy<0>]>;
 
+def SDT_MipsDynAlloc    : SDTypeProfile<1, 1, [SDTCisVT<0, i32>,
+                                               SDTCisVT<1, iPTR>]>;
+
 // Call
 def MipsJmpLink : SDNode<"MipsISD::JmpLink",SDT_MipsJmpLink,
                          [SDNPHasChain, SDNPOutGlue, SDNPOptInGlue,
@@ -99,6 +102,10 @@ def MipsDivRemU   : SDNode<"MipsISD::DivRemU", SDT_MipsDivRem,
 
 def MipsWrapperPIC    : SDNode<"MipsISD::WrapperPIC",  SDTIntUnaryOp>;
 
+// Pointer to dynamically allocated stack area.
+def MipsDynAlloc  : SDNode<"MipsISD::DynAlloc", SDT_MipsDynAlloc,
+                           [SDNPHasChain, SDNPInGlue]>;
+
 //===----------------------------------------------------------------------===//
 // Mips Instruction Predicate Definitions.
 //===----------------------------------------------------------------------===//
@@ -675,6 +682,12 @@ let addr=0 in
 // can be matched. It's similar to Sparc LEA_ADDRi
 def LEA_ADDiu : EffectiveAddress<"addiu\t$dst, ${addr:stackloc}">;
 
+// DynAlloc node points to dynamically allocated stack space.
+// $sp is added to the list of implicitly used registers to prevent dead code
+// elimination from removing instructions that modify $sp.
+let Uses = [SP] in
+def DynAlloc : EffectiveAddress<"addiu\t$dst, ${addr:stackloc}">;
+
 // MADD*/MSUB*
 def MADD  : MArithR<0, "madd", MipsMAdd, 1>;
 def MADDU : MArithR<1, "maddu", MipsMAddu, 1>;
@@ -852,6 +865,9 @@ def : Pat<(setge CPURegs:$lhs, immSExt16:$rhs),
 def : Pat<(setuge CPURegs:$lhs, immSExt16:$rhs),
           (XORi (SLTiu CPURegs:$lhs, immSExt16:$rhs), 1)>;
 
+// select MipsDynAlloc
+def : Pat<(MipsDynAlloc addr:$f), (DynAlloc addr:$f)>;
+
 //===----------------------------------------------------------------------===//
 // Floating Point Support
 //===----------------------------------------------------------------------===//
diff --git a/lib/Target/Mips/MipsMachineFunction.h b/lib/Target/Mips/MipsMachineFunction.h
index df40e6c748..dbb7a67442 100644
--- a/lib/Target/Mips/MipsMachineFunction.h
+++ b/lib/Target/Mips/MipsMachineFunction.h
@@ -27,6 +27,7 @@ namespace llvm {
 class MipsFunctionInfo : public MachineFunctionInfo {
 
 private:
+  MachineFunction& MF;
   /// SRetReturnReg - Some subtargets require that sret lowering includes
   /// returning the value of the returned struct in a register. This field
   /// holds the virtual register into which the sret argument is passed.
@@ -47,6 +48,7 @@ private:
   //                LowerCall except for the frame object for restoring $gp. 
   std::pair<int, int> InArgFIRange, OutArgFIRange;
   int GPFI; // Index of the frame object for restoring $gp 
+  mutable int DynAllocFI; // Frame index of dynamically allocated stack area.   
   unsigned MaxCallFrameSize;
 
   /// AtomicFrameIndex - To implement atomic.swap and atomic.cmp.swap
@@ -55,10 +57,10 @@ private:
   int AtomicFrameIndex;
 public:
   MipsFunctionInfo(MachineFunction& MF)
-  : SRetReturnReg(0), GlobalBaseReg(0),
+  : MF(MF), SRetReturnReg(0), GlobalBaseReg(0),
     VarArgsFrameIndex(0), InArgFIRange(std::make_pair(-1, 0)),
-    OutArgFIRange(std::make_pair(-1, 0)), GPFI(0), MaxCallFrameSize(0),
-    AtomicFrameIndex(-1)
+    OutArgFIRange(std::make_pair(-1, 0)), GPFI(0), DynAllocFI(0),
+    MaxCallFrameSize(0), AtomicFrameIndex(-1)
   {}
 
   bool isInArgFI(int FI) const {
@@ -81,6 +83,16 @@ public:
   bool needGPSaveRestore() const { return getGPFI(); }
   bool isGPFI(int FI) const { return GPFI && GPFI == FI; }
 
+  // The first call to this function creates a frame object for dynamically
+  // allocated stack area.
+  int getDynAllocFI() const {
+    if (!DynAllocFI)
+      DynAllocFI = MF.getFrameInfo()->CreateFixedObject(4, 0, true);
+
+    return DynAllocFI;
+  }
+  bool isDynAllocFI(int FI) const { return DynAllocFI && DynAllocFI == FI; }
+
   unsigned getSRetReturnReg() const { return SRetReturnReg; }
   void setSRetReturnReg(unsigned Reg) { SRetReturnReg = Reg; }
 
diff --git a/lib/Target/Mips/MipsRegisterInfo.cpp b/lib/Target/Mips/MipsRegisterInfo.cpp
index f3f7272730..84b7026aa0 100644
--- a/lib/Target/Mips/MipsRegisterInfo.cpp
+++ b/lib/Target/Mips/MipsRegisterInfo.cpp
@@ -177,12 +177,14 @@ eliminateFrameIndex(MachineBasicBlock::iterator II, int SPAdj,
   int Offset;
 
   // Calculate final offset.
-  // - There is no need to change the offset if the frame object is an outgoing
-  //   argument or a $gp restore location,
+  // - There is no need to change the offset if the frame object is one of the
+  //   following: an outgoing argument, pointer to a dynamically allocated
+  //   stack space or a $gp restore location,
   // - If the frame object is any of the following, its offset must be adjusted
   //   by adding the size of the stack:
   //   incoming argument, callee-saved register location or local variable.  
-  if (MipsFI->isOutArgFI(FrameIndex) || MipsFI->isGPFI(FrameIndex))
+  if (MipsFI->isOutArgFI(FrameIndex) || MipsFI->isGPFI(FrameIndex) ||
+      MipsFI->isDynAllocFI(FrameIndex))
     Offset = spOffset;
   else
     Offset = spOffset + stackSize;
@@ -211,7 +213,7 @@ eliminateFrameIndex(MachineBasicBlock::iterator II, int SPAdj,
   //  3. Locations for callee-saved registers.
   // Everything else is referenced relative to whatever register 
   // getFrameRegister() returns.
-  if (MipsFI->isOutArgFI(FrameIndex) ||
+  if (MipsFI->isOutArgFI(FrameIndex) || MipsFI->isDynAllocFI(FrameIndex) ||
       (FrameIndex >= MinCSFI && FrameIndex <= MaxCSFI))
     FrameReg = Mips::SP;
   else
diff --git a/test/CodeGen/Mips/alloca.ll b/test/CodeGen/Mips/alloca.ll
index 50eeecf991..ff503ecce0 100644
--- a/test/CodeGen/Mips/alloca.ll
+++ b/test/CodeGen/Mips/alloca.ll
@@ -4,15 +4,15 @@ define i32 @twoalloca(i32 %size) nounwind {
 entry:
 ; CHECK: subu  $[[T0:[0-9]+]], $sp, $[[SZ:[0-9]+]]
 ; CHECK: addu  $sp, $zero, $[[T0]]
-; CHECK: addu  $[[SP1:[0-9]+]], $zero, $sp
-; CHECK: subu  $[[T1:[0-9]+]], $sp, $[[SZ]]
-; CHECK: addu  $sp, $zero, $[[T1]]
-; CHECK: addu  $[[SP2:[0-9]+]], $zero, $sp
+; CHECK: addiu $[[T1:[0-9]+]], $sp, [[OFF:[0-9]+]]
+; CHECK: subu  $[[T2:[0-9]+]], $sp, $[[SZ]]
+; CHECK: addu  $sp, $zero, $[[T2]]
+; CHECK: addiu $[[T3:[0-9]+]], $sp, [[OFF]]
 ; CHECK: lw  $25, %call16(foo)($gp)
-; CHECK: addiu $4, $[[SP1]], 24
+; CHECK: addu $4, $zero, $[[T1]]
 ; CHECK: jalr  $25
 ; CHECK: lw  $25, %call16(foo)($gp)
-; CHECK: addiu $4, $[[SP2]], 24
+; CHECK: addu $4, $zero, $[[T3]]
 ; CHECK: jalr  $25
   %tmp1 = alloca i8, i32 %size, align 4
   %add.ptr = getelementptr inbounds i8* %tmp1, i32 5
@@ -29,3 +29,72 @@ declare void @foo2(double, double, i32)
 
 declare i32 @foo(i8*)
 
+@.str = private unnamed_addr constant [22 x i8] c"%d %d %d %d %d %d %d\0A\00", align 1
+
+define i32 @alloca2(i32 %size) nounwind {
+entry:
+; dynamic allocated stack area and $gp restore slot have the same offsets
+; relative to $sp.
+;
+; CHECK: alloca2
+; CHECK: .cprestore [[OFF:[0-9]+]]
+; CHECK: subu  $[[T0:[0-9]+]], $sp, $[[SZ:[0-9]+]]
+; CHECK: addu  $sp, $zero, $[[T0]]
+; CHECK: addiu $[[T1:[0-9]+]], $sp, [[OFF]]
+
+  %tmp1 = alloca i8, i32 %size, align 4
+  %0 = bitcast i8* %tmp1 to i32*
+  %cmp = icmp sgt i32 %size, 10
+  br i1 %cmp, label %if.then, label %if.else
+
+if.then:                                          ; preds = %entry
+; CHECK: addiu $4, $[[T1]], 40
+
+  %add.ptr = getelementptr inbounds i8* %tmp1, i32 40
+  %1 = bitcast i8* %add.ptr to i32*
+  call void @foo3(i32* %1) nounwind
+  %arrayidx15.pre = getelementptr inbounds i8* %tmp1, i32 12
+  %.pre = bitcast i8* %arrayidx15.pre to i32*
+  br label %if.end
+
+if.else:                                          ; preds = %entry
+; CHECK: addiu $4, $[[T1]], 12
+
+  %add.ptr5 = getelementptr inbounds i8* %tmp1, i32 12
+  %2 = bitcast i8* %add.ptr5 to i32*
+  call void @foo3(i32* %2) nounwind
+  br label %if.end
+
+if.end:                                           ; preds = %if.else, %if.then
+; CHECK: lw  $5, 0($[[T1]])
+; CHECK: lw  $25, %call16(printf)
+
+  %.pre-phi = phi i32* [ %2, %if.else ], [ %.pre, %if.then ]
+  %tmp7 = load i32* %0, align 4, !tbaa !0
+  %arrayidx9 = getelementptr inbounds i8* %tmp1, i32 4
+  %3 = bitcast i8* %arrayidx9 to i32*
+  %tmp10 = load i32* %3, align 4, !tbaa !0
+  %arrayidx12 = getelementptr inbounds i8* %tmp1, i32 8
+  %4 = bitcast i8* %arrayidx12 to i32*
+  %tmp13 = load i32* %4, align 4, !tbaa !0
+  %tmp16 = load i32* %.pre-phi, align 4, !tbaa !0
+  %arrayidx18 = getelementptr inbounds i8* %tmp1, i32 16
+  %5 = bitcast i8* %arrayidx18 to i32*
+  %tmp19 = load i32* %5, align 4, !tbaa !0
+  %arrayidx21 = getelementptr inbounds i8* %tmp1, i32 20
+  %6 = bitcast i8* %arrayidx21 to i32*
+  %tmp22 = load i32* %6, align 4, !tbaa !0
+  %arrayidx24 = getelementptr inbounds i8* %tmp1, i32 24
+  %7 = bitcast i8* %arrayidx24 to i32*
+  %tmp25 = load i32* %7, align 4, !tbaa !0
+  %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([22 x i8]* @.str, i32 0, i32 0), i32 %tmp7, i32 %tmp10, i32 %tmp13, i32 %tmp16, i32 %tmp19, i32 %tmp22, i32 %tmp25) nounwind
+  ret i32 0
+}
+
+declare void @foo3(i32*)
+
+declare i32 @printf(i8* nocapture, ...) nounwind
+
+!0 = metadata !{metadata !"int", metadata !1}
+!1 = metadata !{metadata !"omnipotent char", metadata !2}
+!2 = metadata !{metadata !"Simple C/C++ TBAA", null}