Lower the MBlaze target specific calling conventions for "interrupt_handler"

and "save_volatiles" correctly. This completes the custom calling convention
functionality changes for the MBlaze backend that were started in 121888.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121891 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 119 insertions, 12 deletions

diff --git a/lib/Target/MBlaze/MBlazeFrameInfo.cpp b/lib/Target/MBlaze/MBlazeFrameInfo.cpp
index 77897232f7..3b5023d3a7 100644
--- a/lib/Target/MBlaze/MBlazeFrameInfo.cpp
+++ b/lib/Target/MBlaze/MBlazeFrameInfo.cpp
@@ -132,6 +132,92 @@ static void analyzeFrameIndexes(MachineFunction &MF) {
   MBlazeFI->setStackAdjust(StackAdjust);
 }
 
+static void interruptFrameLayout(MachineFunction &MF) {
+  const Function *F = MF.getFunction();
+  llvm::CallingConv::ID CallConv = F->getCallingConv();
+
+  // If this function is not using either the interrupt_handler
+  // calling convention or the save_volatiles calling convention
+  // then we don't need to do any additional frame layout.
+  if (CallConv != llvm::CallingConv::MBLAZE_INTR &&
+      CallConv != llvm::CallingConv::MBLAZE_SVOL)
+      return;
+
+  MachineFrameInfo *MFI = MF.getFrameInfo();
+  const MachineRegisterInfo &MRI = MF.getRegInfo();
+  const MBlazeInstrInfo &TII =
+    *static_cast<const MBlazeInstrInfo*>(MF.getTarget().getInstrInfo());
+
+  // Determine if the calling convention is the interrupt_handler
+  // calling convention. Some pieces of the prologue and epilogue
+  // only need to be emitted if we are lowering and interrupt handler.
+  bool isIntr = CallConv == llvm::CallingConv::MBLAZE_INTR;
+
+  // Determine where to put prologue and epilogue additions
+  MachineBasicBlock &MENT   = MF.front();
+  MachineBasicBlock &MEXT   = MF.back();
+
+  MachineBasicBlock::iterator MENTI = MENT.begin();
+  MachineBasicBlock::iterator MEXTI = prior(MEXT.end());
+
+  DebugLoc ENTDL = MENTI != MENT.end() ? MENTI->getDebugLoc() : DebugLoc();
+  DebugLoc EXTDL = MEXTI != MEXT.end() ? MEXTI->getDebugLoc() : DebugLoc();
+
+  // Store the frame indexes generated during prologue additions for use
+  // when we are generating the epilogue additions.
+  SmallVector<int, 10> VFI;
+
+  // Build the prologue SWI for R3 - R12 if needed. Note that R11 must
+  // always have a SWI because it is used when processing RMSR.
+  for (unsigned r = MBlaze::R3; r <= MBlaze::R12; ++r) {
+    if (!MRI.isPhysRegUsed(r) && !(isIntr && r == MBlaze::R11)) continue;
+    
+    int FI = MFI->CreateStackObject(4,4,false,false);
+    VFI.push_back(FI);
+
+    BuildMI(MENT, MENTI, ENTDL, TII.get(MBlaze::SWI), r)
+      .addFrameIndex(FI).addImm(0);
+  }
+    
+  // Build the prologue SWI for R17, R18
+  int R17FI = MFI->CreateStackObject(4,4,false,false);
+  int R18FI = MFI->CreateStackObject(4,4,false,false);
+
+  BuildMI(MENT, MENTI, ENTDL, TII.get(MBlaze::SWI), MBlaze::R17)
+    .addFrameIndex(R17FI).addImm(0);
+    
+  BuildMI(MENT, MENTI, ENTDL, TII.get(MBlaze::SWI), MBlaze::R18)
+    .addFrameIndex(R18FI).addImm(0);
+
+  // Buid the prologue SWI and the epilogue LWI for RMSR if needed
+  if (isIntr) {
+    int MSRFI = MFI->CreateStackObject(4,4,false,false);
+    BuildMI(MENT, MENTI, ENTDL, TII.get(MBlaze::MFS), MBlaze::R11)
+      .addReg(MBlaze::RMSR);
+    BuildMI(MENT, MENTI, ENTDL, TII.get(MBlaze::SWI), MBlaze::R11)
+      .addFrameIndex(MSRFI).addImm(0);
+
+    BuildMI(MEXT, MEXTI, EXTDL, TII.get(MBlaze::LWI), MBlaze::R11)
+      .addFrameIndex(MSRFI).addImm(0);
+    BuildMI(MEXT, MEXTI, EXTDL, TII.get(MBlaze::MTS), MBlaze::RMSR)
+      .addReg(MBlaze::R11);
+  }
+
+  // Build the epilogue LWI for R17, R18
+  BuildMI(MEXT, MEXTI, EXTDL, TII.get(MBlaze::LWI), MBlaze::R18)
+    .addFrameIndex(R18FI).addImm(0);
+
+  BuildMI(MEXT, MEXTI, EXTDL, TII.get(MBlaze::LWI), MBlaze::R17)
+    .addFrameIndex(R17FI).addImm(0);
+
+  // Build the epilogue LWI for R3 - R12 if needed
+  for (unsigned r = MBlaze::R12, i = VFI.size(); r >= MBlaze::R3; --r) {
+    if (!MRI.isPhysRegUsed(r)) continue;
+    BuildMI(MEXT, MEXTI, EXTDL, TII.get(MBlaze::LWI), r)
+      .addFrameIndex(VFI[--i]).addImm(0);
+  }
+}
+
 static void determineFrameLayout(MachineFunction &MF) {
   MachineFrameInfo *MFI = MF.getFrameInfo();
   MBlazeFunctionInfo *MBlazeFI = MF.getInfo<MBlazeFunctionInfo>();
@@ -174,6 +260,9 @@ void MBlazeFrameInfo::emitPrologue(MachineFunction &MF) const {
   MachineBasicBlock::iterator MBBI = MBB.begin();
   DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
 
+  llvm::CallingConv::ID CallConv = MF.getFunction()->getCallingConv();
+  bool requiresRA = CallConv == llvm::CallingConv::MBLAZE_INTR;
+
   // Determine the correct frame layout
   determineFrameLayout(MF);
 
@@ -181,7 +270,7 @@ void MBlazeFrameInfo::emitPrologue(MachineFunction &MF) const {
   unsigned StackSize = MFI->getStackSize();
 
   // No need to allocate space on the stack.
-  if (StackSize == 0 && !MFI->adjustsStack()) return;
+  if (StackSize == 0 && !MFI->adjustsStack() && !requiresRA) return;
 
   int FPOffset = MBlazeFI->getFPStackOffset();
   int RAOffset = MBlazeFI->getRAStackOffset();
@@ -191,7 +280,7 @@ void MBlazeFrameInfo::emitPrologue(MachineFunction &MF) const {
       .addReg(MBlaze::R1).addImm(-StackSize);
 
   // swi  R15, R1, stack_loc
-  if (MFI->adjustsStack()) {
+  if (MFI->adjustsStack() || requiresRA) {
     BuildMI(MBB, MBBI, DL, TII.get(MBlaze::SWI))
         .addReg(MBlaze::R15).addReg(MBlaze::R1).addImm(RAOffset);
   }
@@ -217,6 +306,9 @@ void MBlazeFrameInfo::emitEpilogue(MachineFunction &MF,
 
   DebugLoc dl = MBBI->getDebugLoc();
 
+  llvm::CallingConv::ID CallConv = MF.getFunction()->getCallingConv();
+  bool requiresRA = CallConv == llvm::CallingConv::MBLAZE_INTR;
+
   // Get the FI's where RA and FP are saved.
   int FPOffset = MBlazeFI->getFPStackOffset();
   int RAOffset = MBlazeFI->getRAStackOffset();
@@ -232,7 +324,7 @@ void MBlazeFrameInfo::emitEpilogue(MachineFunction &MF,
   }
 
   // lwi R15, R1, stack_loc
-  if (MFI->adjustsStack()) {
+  if (MFI->adjustsStack() || requiresRA) {
     BuildMI(MBB, MBBI, dl, TII.get(MBlaze::LWI), MBlaze::R15)
       .addReg(MBlaze::R1).addImm(RAOffset);
   }
@@ -251,8 +343,10 @@ void MBlazeFrameInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
                                                            const {
   MachineFrameInfo *MFI = MF.getFrameInfo();
   MBlazeFunctionInfo *MBlazeFI = MF.getInfo<MBlazeFunctionInfo>();
+  llvm::CallingConv::ID CallConv = MF.getFunction()->getCallingConv();
+  bool requiresRA = CallConv == llvm::CallingConv::MBLAZE_INTR;
 
-  if (MFI->adjustsStack()) {
+  if (MFI->adjustsStack() || requiresRA) {
     MBlazeFI->setRAStackOffset(0);
     MFI->CreateFixedObject(4,0,true);
   }
@@ -262,5 +356,6 @@ void MBlazeFrameInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
     MFI->CreateFixedObject(4,4,true);
   }
 
+  interruptFrameLayout(MF);
   analyzeFrameIndexes(MF);
 }
diff --git a/lib/Target/MBlaze/MBlazeISelLowering.cpp b/lib/Target/MBlaze/MBlazeISelLowering.cpp
index ad7222a4c5..dc7cff8637 100644
--- a/lib/Target/MBlaze/MBlazeISelLowering.cpp
+++ b/lib/Target/MBlaze/MBlazeISelLowering.cpp
@@ -864,13 +864,18 @@ LowerReturn(SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
     Flag = Chain.getValue(1);
   }
 
-  // Return on MBlaze is always a "rtsd R15, 8"
+  // If this function is using the interrupt_handler calling convention
+  // then use "rtid r14, 0" otherwise use "rtsd r15, 8"
+  unsigned Ret = (CallConv == llvm::CallingConv::MBLAZE_INTR) ? MBlazeISD::IRet 
+                                                              : MBlazeISD::Ret;
+  unsigned Reg = (CallConv == llvm::CallingConv::MBLAZE_INTR) ? MBlaze::R14 
+                                                              : MBlaze::R15;
+  SDValue DReg = DAG.getRegister(Reg, MVT::i32);
+
   if (Flag.getNode())
-    return DAG.getNode(MBlazeISD::Ret, dl, MVT::Other,
-                       Chain, DAG.getRegister(MBlaze::R15, MVT::i32), Flag);
-  else // Return Void
-    return DAG.getNode(MBlazeISD::Ret, dl, MVT::Other,
-                       Chain, DAG.getRegister(MBlaze::R15, MVT::i32));
+    return DAG.getNode(Ret, dl, MVT::Other, Chain, DReg, Flag);
+
+  return DAG.getNode(Ret, dl, MVT::Other, Chain, DReg);
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/lib/Target/MBlaze/MBlazeISelLowering.h b/lib/Target/MBlaze/MBlazeISelLowering.h
index 4f09851e7f..aa1c9aa3aa 100644
--- a/lib/Target/MBlaze/MBlazeISelLowering.h
+++ b/lib/Target/MBlaze/MBlazeISelLowering.h
@@ -78,8 +78,11 @@ namespace llvm {
       // Integer Compare
       ICmp,
 
-      // Return
-      Ret
+      // Return from subroutine
+      Ret,
+
+      // Return from interrupt
+      IRet
     };
   }
 
diff --git a/lib/Target/MBlaze/MBlazeInstrInfo.td b/lib/Target/MBlaze/MBlazeInstrInfo.td
index cf69efa877..39ddd6ad35 100644
--- a/lib/Target/MBlaze/MBlazeInstrInfo.td
+++ b/lib/Target/MBlaze/MBlazeInstrInfo.td
@@ -18,6 +18,7 @@ include "MBlazeInstrFormats.td"
 
 // def SDTMBlazeSelectCC : SDTypeProfile<1, 3, [SDTCisSameAs<0, 1>]>;
 def SDT_MBlazeRet     : SDTypeProfile<0, 1, [SDTCisInt<0>]>;
+def SDT_MBlazeIRet    : SDTypeProfile<0, 1, [SDTCisInt<0>]>;
 def SDT_MBlazeJmpLink : SDTypeProfile<0, 1, [SDTCisVT<0, i32>]>;
 def SDT_MBCallSeqStart : SDCallSeqStart<[SDTCisVT<0, i32>]>;
 def SDT_MBCallSeqEnd   : SDCallSeqEnd<[SDTCisVT<0, i32>, SDTCisVT<1, i32>]>;
@@ -28,6 +29,8 @@ def SDT_MBCallSeqEnd   : SDCallSeqEnd<[SDTCisVT<0, i32>, SDTCisVT<1, i32>]>;
 
 def MBlazeRet     : SDNode<"MBlazeISD::Ret", SDT_MBlazeRet,
                            [SDNPHasChain, SDNPOptInFlag]>;
+def MBlazeIRet    : SDNode<"MBlazeISD::IRet", SDT_MBlazeIRet,
+                           [SDNPHasChain, SDNPOptInFlag]>;
 
 def MBlazeJmpLink : SDNode<"MBlazeISD::JmpLink",SDT_MBlazeJmpLink,
                            [SDNPHasChain,SDNPOptInFlag,SDNPOutFlag]>;
@@ -727,6 +730,7 @@ def : Pat<(selectcc (i32 GPR:$L), (i32 GPR:$R),
 
 // Ret instructions
 def : Pat<(MBlazeRet GPR:$target), (RTSD GPR:$target, 0x8)>;
+def : Pat<(MBlazeIRet GPR:$target), (RTID GPR:$target, 0x0)>;
 
 // BR instructions
 def : Pat<(br bb:$T), (BRID bb:$T)>;