Revert r151623 "Some ARM implementaions, e.g. A-series, does return stack prediction. ...", it is breaking the Clang build during the Compiler-RT part.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151630 91177308-0d34-0410-b5e6-96231b3b80d8

8 files changed, 9 insertions, 135 deletions

diff --git a/lib/Target/ARM/ARM.td b/lib/Target/ARM/ARM.td
index 16af8cfbe2..076424e9e9 100644
--- a/lib/Target/ARM/ARM.td
+++ b/lib/Target/ARM/ARM.td
@@ -89,11 +89,6 @@ def FeatureAvoidPartialCPSR : SubtargetFeature<"avoid-partial-cpsr",
                                                "AvoidCPSRPartialUpdate", "true",
                                  "Avoid CPSR partial update for OOO execution">;
 
-// Some processors perform return stack prediction. CodeGen should avoid issue
-// "normal" call instructions to callees which do not return.
-def FeatureHasRAS : SubtargetFeature<"ras", "HasRAS", "true",
-                                     "Has return address stack">;
-
 /// Some M architectures don't have the DSP extension (v7E-M vs. v7M)
 def FeatureDSPThumb2 : SubtargetFeature<"t2dsp", "Thumb2DSP", "true",
                                  "Supports v7 DSP instructions in Thumb2">;
@@ -209,14 +204,13 @@ def : Processor<"arm1156t2f-s",     ARMV6Itineraries, [HasV6T2Ops, FeatureVFP2,
 // V7a Processors.
 def : Processor<"cortex-a8",        CortexA8Itineraries,
                                     [ProcA8, HasV7Ops, FeatureNEON, FeatureDB,
-                                     FeatureDSPThumb2, FeatureHasRAS]>;
+                                     FeatureDSPThumb2]>;
 def : Processor<"cortex-a9",        CortexA9Itineraries,
                                     [ProcA9, HasV7Ops, FeatureNEON, FeatureDB,
-                                     FeatureDSPThumb2, FeatureHasRAS]>;
+                                     FeatureDSPThumb2]>;
 def : Processor<"cortex-a9-mp",     CortexA9Itineraries,
                                     [ProcA9, HasV7Ops, FeatureNEON, FeatureDB,
-                                     FeatureDSPThumb2, FeatureMP,
-                                     FeatureHasRAS]>;
+                                     FeatureDSPThumb2, FeatureMP]>;
 
 // V7M Processors.
 def : ProcNoItin<"cortex-m3",       [HasV7Ops,
diff --git a/lib/Target/ARM/ARMAsmPrinter.cpp b/lib/Target/ARM/ARMAsmPrinter.cpp
index 9d8c97a832..8d93420727 100644
--- a/lib/Target/ARM/ARMAsmPrinter.cpp
+++ b/lib/Target/ARM/ARMAsmPrinter.cpp
@@ -1343,60 +1343,6 @@ void ARMAsmPrinter::EmitInstruction(const MachineInstr *MI) {
     }
     return;
   }
-  case ARM::BMOVPCBr9_CALL:
-  case ARM::BMOVPCB_CALL: {
-    {
-      MCInst TmpInst;
-      TmpInst.setOpcode(ARM::MOVr);
-      TmpInst.addOperand(MCOperand::CreateReg(ARM::LR));
-      TmpInst.addOperand(MCOperand::CreateReg(ARM::PC));
-      // Add predicate operands.
-      TmpInst.addOperand(MCOperand::CreateImm(ARMCC::AL));
-      TmpInst.addOperand(MCOperand::CreateReg(0));
-      // Add 's' bit operand (always reg0 for this)
-      TmpInst.addOperand(MCOperand::CreateReg(0));
-      OutStreamer.EmitInstruction(TmpInst);
-    }
-    {
-      MCInst TmpInst;
-      TmpInst.setOpcode(ARM::Bcc);
-      const GlobalValue *GV = MI->getOperand(0).getGlobal();
-      MCSymbol *GVSym = Mang->getSymbol(GV);
-      const MCExpr *GVSymExpr = MCSymbolRefExpr::Create(GVSym, OutContext);
-      TmpInst.addOperand(MCOperand::CreateExpr(GVSymExpr));
-      // Add predicate operands.
-      TmpInst.addOperand(MCOperand::CreateImm(ARMCC::AL));
-      TmpInst.addOperand(MCOperand::CreateReg(0));
-      OutStreamer.EmitInstruction(TmpInst);
-    }
-    return;
-  }
-  case ARM::t2BMOVPCBr9_CALL:
-  case ARM::t2BMOVPCB_CALL: {
-    {
-      MCInst TmpInst;
-      TmpInst.setOpcode(ARM::tMOVr);
-      TmpInst.addOperand(MCOperand::CreateReg(ARM::LR));
-      TmpInst.addOperand(MCOperand::CreateReg(ARM::PC));
-      // Add predicate operands.
-      TmpInst.addOperand(MCOperand::CreateImm(ARMCC::AL));
-      TmpInst.addOperand(MCOperand::CreateReg(0));
-      OutStreamer.EmitInstruction(TmpInst);
-    }
-    {
-      MCInst TmpInst;
-      TmpInst.setOpcode(ARM::t2B);
-      const GlobalValue *GV = MI->getOperand(0).getGlobal();
-      MCSymbol *GVSym = Mang->getSymbol(GV);
-      const MCExpr *GVSymExpr = MCSymbolRefExpr::Create(GVSym, OutContext);
-      TmpInst.addOperand(MCOperand::CreateExpr(GVSymExpr));
-      // Add predicate operands.
-      TmpInst.addOperand(MCOperand::CreateImm(ARMCC::AL));
-      TmpInst.addOperand(MCOperand::CreateReg(0));
-      OutStreamer.EmitInstruction(TmpInst);
-    }
-    return;
-  }
   case ARM::MOVi16_ga_pcrel:
   case ARM::t2MOVi16_ga_pcrel: {
     MCInst TmpInst;
diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index ab8470623a..aa51cedb63 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -1286,7 +1286,7 @@ void ARMTargetLowering::PassF64ArgInRegs(DebugLoc dl, SelectionDAG &DAG,
 SDValue
 ARMTargetLowering::LowerCall(SDValue Chain, SDValue Callee,
                              CallingConv::ID CallConv, bool isVarArg,
-                             bool doesNotRet, bool &isTailCall,
+                             bool &isTailCall,
                              const SmallVectorImpl<ISD::OutputArg> &Outs,
                              const SmallVectorImpl<SDValue> &OutVals,
                              const SmallVectorImpl<ISD::InputArg> &Ins,
@@ -1582,20 +1582,12 @@ ARMTargetLowering::LowerCall(SDValue Chain, SDValue Callee,
   if (Subtarget->isThumb()) {
     if ((!isDirect || isARMFunc) && !Subtarget->hasV5TOps())
       CallOpc = ARMISD::CALL_NOLINK;
-    else if (doesNotRet && !isARMFunc &&
-             Subtarget->hasRAS() && !Subtarget->isThumb1Only())
-      // "mov lr, pc; b _foo" to avoid confusing the RSP
-      CallOpc = ARMISD::CALL_NOLINK;
     else
       CallOpc = isARMFunc ? ARMISD::CALL : ARMISD::tCALL;
   } else {
-    if (!isDirect && !Subtarget->hasV5TOps()) {
-      CallOpc = ARMISD::CALL_NOLINK;
-    } else if (doesNotRet && Subtarget->hasRAS())
-      // "mov lr, pc; b _foo" to avoid confusing the RSP
-      CallOpc = ARMISD::CALL_NOLINK;
-    else
-      CallOpc = isLocalARMFunc ? ARMISD::CALL_PRED : ARMISD::CALL;
+    CallOpc = (isDirect || Subtarget->hasV5TOps())
+      ? (isLocalARMFunc ? ARMISD::CALL_PRED : ARMISD::CALL)
+      : ARMISD::CALL_NOLINK;
   }
 
   std::vector<SDValue> Ops;
@@ -2088,8 +2080,7 @@ ARMTargetLowering::LowerToTLSGeneralDynamicModel(GlobalAddressSDNode *GA,
   std::pair<SDValue, SDValue> CallResult =
     LowerCallTo(Chain, (Type *) Type::getInt32Ty(*DAG.getContext()),
                 false, false, false, false,
-                0, CallingConv::C, /*isTailCall=*/false,
-                /*doesNotRet=*/false, /*isReturnValueUsed=*/true,
+                0, CallingConv::C, false, /*isReturnValueUsed=*/true,
                 DAG.getExternalSymbol("__tls_get_addr", PtrVT), Args, DAG, dl);
   return CallResult.first;
 }
diff --git a/lib/Target/ARM/ARMISelLowering.h b/lib/Target/ARM/ARMISelLowering.h
index 7f12293526..a72a476e96 100644
--- a/lib/Target/ARM/ARMISelLowering.h
+++ b/lib/Target/ARM/ARMISelLowering.h
@@ -462,7 +462,7 @@ namespace llvm {
     virtual SDValue
       LowerCall(SDValue Chain, SDValue Callee,
                 CallingConv::ID CallConv, bool isVarArg,
-                bool doesNotRet, bool &isTailCall,
+                bool &isTailCall,
                 const SmallVectorImpl<ISD::OutputArg> &Outs,
                 const SmallVectorImpl<SDValue> &OutVals,
                 const SmallVectorImpl<ISD::InputArg> &Ins,
diff --git a/lib/Target/ARM/ARMInstrInfo.td b/lib/Target/ARM/ARMInstrInfo.td
index 6f510ba665..1c2976d354 100644
--- a/lib/Target/ARM/ARMInstrInfo.td
+++ b/lib/Target/ARM/ARMInstrInfo.td
@@ -1951,13 +1951,6 @@ let isCall = 1,
   def BMOVPCRX_CALL : ARMPseudoInst<(outs), (ins tGPR:$func, variable_ops),
                    8, IIC_Br, [(ARMcall_nolink tGPR:$func)]>,
                    Requires<[IsARM, NoV4T, IsNotIOS]>;
-
-  // mov lr, pc; b if callee is marked noreturn to avoid confusing the
-  // return stack predictor.
-  def BMOVPCB_CALL : ARMPseudoInst<(outs),
-                                   (ins bl_target:$func, variable_ops),
-                               8, IIC_Br, [(ARMcall_nolink tglobaladdr:$func)]>,
-                      Requires<[IsARM, IsNotIOS]>;
 }
 
 let isCall = 1,
@@ -2000,12 +1993,6 @@ let isCall = 1,
   def BMOVPCRXr9_CALL : ARMPseudoInst<(outs), (ins tGPR:$func, variable_ops),
                   8, IIC_Br, [(ARMcall_nolink tGPR:$func)]>,
                   Requires<[IsARM, NoV4T, IsIOS]>;
-
-  // mov lr, pc; b if callee is marked noreturn to avoid confusing the
-  // return stack predictor.
-  def BMOVPCBr9_CALL : ARMPseudoInst<(outs),(ins bl_target:$func, variable_ops),
-                               8, IIC_Br, [(ARMcall_nolink tglobaladdr:$func)]>,
-                        Requires<[IsARM, IsIOS]>;
 }
 
 let isBranch = 1, isTerminator = 1 in {
@@ -4910,12 +4897,6 @@ def : ARMPat<(ARMcall texternalsym:$func), (BL texternalsym:$func)>,
       Requires<[IsARM, IsNotIOS]>;
 def : ARMPat<(ARMcall texternalsym:$func), (BLr9 texternalsym:$func)>,
       Requires<[IsARM, IsIOS]>;
-def : ARMPat<(ARMcall_nolink texternalsym:$func),
-             (BMOVPCB_CALL texternalsym:$func)>,
-      Requires<[IsARM, IsNotIOS]>;
-def : ARMPat<(ARMcall_nolink texternalsym:$func),
-             (BMOVPCBr9_CALL texternalsym:$func)>,
-      Requires<[IsARM, IsIOS]>;
 
 // zextload i1 -> zextload i8
 def : ARMPat<(zextloadi1 addrmode_imm12:$addr), (LDRBi12 addrmode_imm12:$addr)>;
diff --git a/lib/Target/ARM/ARMInstrThumb2.td b/lib/Target/ARM/ARMInstrThumb2.td
index e8984e1838..88b6a2f45d 100644
--- a/lib/Target/ARM/ARMInstrThumb2.td
+++ b/lib/Target/ARM/ARMInstrThumb2.td
@@ -3277,38 +3277,6 @@ let isCall = 1, isTerminator = 1, isReturn = 1, isBarrier = 1 in {
                  Requires<[IsThumb2, IsIOS]>;
 }
 
-let isCall = 1,
-  // On non-IOS platforms R9 is callee-saved.
-  Defs = [LR], Uses = [SP] in {
-  // mov lr, pc; b if callee is marked noreturn to avoid confusing the
-  // return stack predictor.
-  def t2BMOVPCB_CALL : tPseudoInst<(outs),
-                                   (ins t_bltarget:$func, variable_ops),
-                               6, IIC_Br, [(ARMcall_nolink tglobaladdr:$func)]>,
-                        Requires<[IsThumb, IsNotIOS]>;
-}
-
-let isCall = 1,
-  // On IOS R9 is call-clobbered.
-  // R7 is marked as a use to prevent frame-pointer assignments from being
-  // moved above / below calls.
-  Defs = [LR], Uses = [R7, SP] in {
-  // mov lr, pc; b if callee is marked noreturn to avoid confusing the
-  // return stack predictor.
-  def t2BMOVPCBr9_CALL : tPseudoInst<(outs),
-                                     (ins t_bltarget:$func, variable_ops),
-                               6, IIC_Br, [(ARMcall_nolink tglobaladdr:$func)]>,
-                        Requires<[IsThumb, IsIOS]>;
-}
-
-// Direct calls
-def : T2Pat<(ARMcall_nolink texternalsym:$func),
-            (t2BMOVPCB_CALL texternalsym:$func)>,
-      Requires<[IsThumb, IsNotIOS]>;
-def : T2Pat<(ARMcall_nolink texternalsym:$func),
-            (t2BMOVPCBr9_CALL texternalsym:$func)>,
-      Requires<[IsThumb, IsIOS]>;
-
 // IT block
 let Defs = [ITSTATE] in
 def t2IT : Thumb2XI<(outs), (ins it_pred:$cc, it_mask:$mask),
diff --git a/lib/Target/ARM/ARMSelectionDAGInfo.cpp b/lib/Target/ARM/ARMSelectionDAGInfo.cpp
index e2530d07e2..3113b62c1f 100644
--- a/lib/Target/ARM/ARMSelectionDAGInfo.cpp
+++ b/lib/Target/ARM/ARMSelectionDAGInfo.cpp
@@ -189,7 +189,6 @@ EmitTargetCodeForMemset(SelectionDAG &DAG, DebugLoc dl,
                     0,     // number of fixed arguments
                     TLI.getLibcallCallingConv(RTLIB::MEMSET), // call conv
                     false, // is tail call
-                    false, // does not return
                     false, // is return val used
                     DAG.getExternalSymbol(TLI.getLibcallName(RTLIB::MEMSET),
                                           TLI.getPointerTy()), // callee
diff --git a/lib/Target/ARM/ARMSubtarget.h b/lib/Target/ARM/ARMSubtarget.h
index c94795f753..58ff8fb5fd 100644
--- a/lib/Target/ARM/ARMSubtarget.h
+++ b/lib/Target/ARM/ARMSubtarget.h
@@ -125,10 +125,6 @@ protected:
   /// CPSR setting instruction.
   bool AvoidCPSRPartialUpdate;
 
-  /// HasRAS - Some processors perform return stack prediction. CodeGen should
-  /// avoid issue "normal" call instructions to callees which do not return.
-  bool HasRAS;
-
   /// HasMPExtension - True if the subtarget supports Multiprocessing
   /// extension (ARMv7 only).
   bool HasMPExtension;
@@ -218,7 +214,6 @@ protected:
   bool isFPOnlySP() const { return FPOnlySP; }
   bool prefers32BitThumb() const { return Pref32BitThumb; }
   bool avoidCPSRPartialUpdate() const { return AvoidCPSRPartialUpdate; }
-  bool hasRAS() const { return HasRAS; }
   bool hasMPExtension() const { return HasMPExtension; }
   bool hasThumb2DSP() const { return Thumb2DSP; }