Improve Mips back-end's handling of DBG_VALUE.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134224 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/Mips/MipsAsmPrinter.cpp

@@ -38,6 +38,8 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Analysis/DebugInfo.h"
+
 using namespace llvm;
 
 namespace {
@@ -75,6 +77,10 @@ namespace {
     void EmitInstruction(const MachineInstr *MI) {
       SmallString<128> Str;
       raw_svector_ostream OS(Str);
+
+      if (MI->isDebugValue())
+        PrintDebugValueComment(MI, OS);
+
       printInstruction(MI, OS);
       OutStreamer.EmitRawText(OS.str());
     }
@@ -86,6 +92,9 @@ namespace {
 
     virtual void EmitFunctionEntryLabel();
     void EmitStartOfAsmFile(Module &M);
+    virtual MachineLocation getDebugValueLocation(const MachineInstr *MI) const;
+
+    void PrintDebugValueComment(const MachineInstr *MI, raw_ostream &OS);
   };
 } // end of anonymous namespace
 
@@ -441,6 +450,21 @@ void MipsAsmPrinter::EmitStartOfAsmFile(Module &M) {
   OutStreamer.EmitRawText(StringRef("\t.previous"));
 }
 
+MachineLocation
+MipsAsmPrinter::getDebugValueLocation(const MachineInstr *MI) const {
+  // Handles frame addresses emitted in MipsInstrInfo::emitFrameIndexDebugValue.
+  assert(MI->getNumOperands() == 4 && "Invalid no. of machine operands!");
+  assert(MI->getOperand(0).isReg() && MI->getOperand(1).isImm() &&
+         "Unexpected MachineOperand types");
+  return MachineLocation(MI->getOperand(0).getReg(),
+                         MI->getOperand(1).getImm());
+}
+
+void MipsAsmPrinter::PrintDebugValueComment(const MachineInstr *MI,
+                                           raw_ostream &OS) {
+  // TODO: implement
+}
+
 // Force static initialization.
 extern "C" void LLVMInitializeMipsAsmPrinter() {
   RegisterAsmPrinter<MipsAsmPrinter> X(TheMipsTarget);

lib/Target/Mips/MipsInstrInfo.cpp

@@ -217,6 +217,15 @@ loadRegFromStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
     llvm_unreachable("Register class not handled!");
 }
 
+MachineInstr*
+MipsInstrInfo::emitFrameIndexDebugValue(MachineFunction &MF, int FrameIx,
+                                        uint64_t Offset, const MDNode *MDPtr,
+                                        DebugLoc DL) const {
+  MachineInstrBuilder MIB = BuildMI(MF, DL, get(Mips::DBG_VALUE))
+    .addFrameIndex(FrameIx).addImm(0).addImm(Offset).addMetadata(MDPtr);
+  return &*MIB;
+}
+
 //===----------------------------------------------------------------------===//
 // Branch Analysis
 //===----------------------------------------------------------------------===//

lib/Target/Mips/MipsInstrInfo.h

@@ -224,6 +224,11 @@ public:
                                     const TargetRegisterClass *RC,
                                     const TargetRegisterInfo *TRI) const;
 
+  virtual MachineInstr* emitFrameIndexDebugValue(MachineFunction &MF,
+                                                 int FrameIx, uint64_t Offset,
+                                                 const MDNode *MDPtr,
+                                                 DebugLoc DL) const;
+
   virtual
   bool ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const;
 

lib/Target/Mips/MipsMCAsmInfo.cpp

@@ -16,7 +16,7 @@ using namespace llvm;
 
 MipsMCAsmInfo::MipsMCAsmInfo(const Target &T, StringRef TT) {
   AlignmentIsInBytes          = false;
-  Data16bitsDirective         = "\t.half\t";
+  Data16bitsDirective         = "\t.2byte\t";
   Data32bitsDirective         = "\t.4byte\t";
   Data64bitsDirective         = 0;
   PrivateGlobalPrefix         = "$";

lib/Target/Mips/MipsRegisterInfo.cpp

@@ -35,6 +35,7 @@
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/ADT/BitVector.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/Analysis/DebugInfo.h"
 
 #define GET_REGINFO_MC_DESC
 #define GET_REGINFO_TARGET_DESC
@@ -179,30 +180,6 @@ eliminateFrameIndex(MachineBasicBlock::iterator II, int SPAdj,
                << "spOffset   : " << spOffset << "\n"
                << "stackSize  : " << stackSize << "\n");
 
-  int Offset;
-
-  // Calculate final offset.
-  // - 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) ||
-      MipsFI->isDynAllocFI(FrameIndex))
-    Offset = spOffset;
-  else
-    Offset = spOffset + stackSize;
-
-  Offset    += MI.getOperand(i-1).getImm();
-
-  DEBUG(errs() << "Offset     : " << Offset << "\n" << "<--------->\n");
-
-  unsigned NewReg = 0;
-  int NewImm = 0;
-  MachineBasicBlock &MBB = *MI.getParent();
-  bool ATUsed;
-  unsigned FrameReg;
   const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
   int MinCSFI = 0;
   int MaxCSFI = -1;
@@ -218,12 +195,44 @@ eliminateFrameIndex(MachineBasicBlock::iterator II, int SPAdj,
   //  3. Locations for callee-saved registers.
   // Everything else is referenced relative to whatever register 
   // getFrameRegister() returns.
+  unsigned FrameReg;
+
   if (MipsFI->isOutArgFI(FrameIndex) || MipsFI->isDynAllocFI(FrameIndex) ||
       (FrameIndex >= MinCSFI && FrameIndex <= MaxCSFI))
     FrameReg = Mips::SP;
   else
     FrameReg = getFrameRegister(MF); 
   
+  // Calculate final offset.
+  // - 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.  
+  int Offset;
+
+  if (MipsFI->isOutArgFI(FrameIndex) || MipsFI->isGPFI(FrameIndex) ||
+      MipsFI->isDynAllocFI(FrameIndex))
+    Offset = spOffset;
+  else
+    Offset = spOffset + stackSize;
+
+  if (MI.isDebugValue()) {
+    MI.getOperand(i).ChangeToRegister(FrameReg, false /*isDef*/);
+    MI.getOperand(i+1).ChangeToImmediate(Offset);
+    return;
+  }
+
+  Offset    += MI.getOperand(i-1).getImm();
+
+  DEBUG(errs() << "Offset     : " << Offset << "\n" << "<--------->\n");
+
+  unsigned NewReg = 0;
+  int NewImm = 0;
+  MachineBasicBlock &MBB = *MI.getParent();
+  bool ATUsed;
+
   // Offset fits in the 16-bit field
   if (Offset < 0x8000 && Offset >= -0x8000) {
     NewReg = FrameReg;