Revert "r225811 - Revert "r225808 - [PowerPC] Add StackMap/PatchPoint support""

This re-applies r225808, fixed to avoid problems with SDAG dependencies along
with the preceding fix to ScheduleDAGSDNodes::RegDefIter::InitNodeNumDefs.
These problems caused the original regression tests to assert/segfault on many
(but not all) systems.

Original commit message:

This commit does two things:

 1. Refactors PPCFastISel to use more of the common infrastructure for call
    lowering (this lets us take advantage of this common code for lowering some
    common intrinsics, stackmap/patchpoint among them).

 2. Adds support for stackmap/patchpoint lowering. For the most part, this is
    very similar to the support in the AArch64 target, with the obvious differences
    (different registers, NOP instructions, etc.). The test cases are adapted
    from the AArch64 test cases.

One difference of note is that the patchpoint call sequence takes 24 bytes, so
you can't use less than that (on AArch64 you can go down to 16). Also, as noted
in the docs, we take the patchpoint address to be the actual code address
(assuming the call is local in the TOC-sharing sense), which should yield
higher performance than generating the full cross-DSO indirect-call sequence
and is likely just as useful for JITed code (if not, we'll change it).

StackMaps and Patchpoints are still marked as experimental, and so this support
is doubly experimental. So go ahead and experiment!

llvm-svn: 225909

1 files changed, 54 insertions, 69 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCFastISel.cpp b/llvm/lib/Target/PowerPC/PPCFastISel.cpp
index ddf13ff3cd6..13bd0c7be2c 100644
--- a/llvm/lib/Target/PowerPC/PPCFastISel.cpp
+++ b/llvm/lib/Target/PowerPC/PPCFastISel.cpp
@@ -15,6 +15,7 @@
 
 #include "PPC.h"
 #include "MCTargetDesc/PPCPredicates.h"
+#include "PPCCallingConv.h"
 #include "PPCISelLowering.h"
 #include "PPCSubtarget.h"
 #include "PPCTargetMachine.h"
@@ -119,6 +120,8 @@ class PPCFastISel final : public FastISel {
                              unsigned Op0, bool Op0IsKill,
                              unsigned Op1, bool Op1IsKill);
 
+    bool fastLowerCall(CallLoweringInfo &CLI) override;
+
   // Instruction selection routines.
   private:
     bool SelectLoad(const Instruction *I);
@@ -130,7 +133,6 @@ class PPCFastISel final : public FastISel {
     bool SelectIToFP(const Instruction *I, bool IsSigned);
     bool SelectFPToI(const Instruction *I, bool IsSigned);
     bool SelectBinaryIntOp(const Instruction *I, unsigned ISDOpcode);
-    bool SelectCall(const Instruction *I);
     bool SelectRet(const Instruction *I);
     bool SelectTrunc(const Instruction *I);
     bool SelectIntExt(const Instruction *I);
@@ -174,9 +176,7 @@ class PPCFastISel final : public FastISel {
                          CallingConv::ID CC,
                          unsigned &NumBytes,
                          bool IsVarArg);
-    void finishCall(MVT RetVT, SmallVectorImpl<unsigned> &UsedRegs,
-                    const Instruction *I, CallingConv::ID CC,
-                    unsigned &NumBytes, bool IsVarArg);
+    bool finishCall(MVT RetVT, CallLoweringInfo &CLI, unsigned &NumBytes);
     CCAssignFn *usePPC32CCs(unsigned Flag);
 
   private:
@@ -1339,9 +1339,9 @@ bool PPCFastISel::processCallArgs(SmallVectorImpl<Value*> &Args,
 
 // For a call that we've determined we can fast-select, finish the
 // call sequence and generate a copy to obtain the return value (if any).
-void PPCFastISel::finishCall(MVT RetVT, SmallVectorImpl<unsigned> &UsedRegs,
-                             const Instruction *I, CallingConv::ID CC,
-                             unsigned &NumBytes, bool IsVarArg) {
+bool PPCFastISel::finishCall(MVT RetVT, CallLoweringInfo &CLI, unsigned &NumBytes) {
+  CallingConv::ID CC = CLI.CallConv;
+
   // Issue CallSEQ_END.
   BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
           TII.get(TII.getCallFrameDestroyOpcode()))
@@ -1352,7 +1352,7 @@ void PPCFastISel::finishCall(MVT RetVT, SmallVectorImpl<unsigned> &UsedRegs,
   // any real difficulties there.
   if (RetVT != MVT::isVoid) {
     SmallVector<CCValAssign, 16> RVLocs;
-    CCState CCInfo(CC, IsVarArg, *FuncInfo.MF, RVLocs, *Context);
+    CCState CCInfo(CC, false, *FuncInfo.MF, RVLocs, *Context);
     CCInfo.AnalyzeCallResult(RetVT, RetCC_PPC64_ELF_FIS);
     CCValAssign &VA = RVLocs[0];
     assert(RVLocs.size() == 1 && "No support for multi-reg return values!");
@@ -1397,39 +1397,35 @@ void PPCFastISel::finishCall(MVT RetVT, SmallVectorImpl<unsigned> &UsedRegs,
     }
 
     assert(ResultReg && "ResultReg unset!");
-    UsedRegs.push_back(SourcePhysReg);
-    updateValueMap(I, ResultReg);
+    CLI.InRegs.push_back(SourcePhysReg);
+    CLI.ResultReg = ResultReg;
+    CLI.NumResultRegs = 1;
   }
+
+  return true;
 }
 
-// Attempt to fast-select a call instruction.
-bool PPCFastISel::SelectCall(const Instruction *I) {
-  const CallInst *CI = cast<CallInst>(I);
-  const Value *Callee = CI->getCalledValue();
+bool PPCFastISel::fastLowerCall(CallLoweringInfo &CLI) {
+  CallingConv::ID CC  = CLI.CallConv;
+  bool IsTailCall     = CLI.IsTailCall;
+  bool IsVarArg       = CLI.IsVarArg;
+  const Value *Callee = CLI.Callee;
+  const char *SymName = CLI.SymName;
 
-  // Can't handle inline asm.
-  if (isa<InlineAsm>(Callee))
+  if (!Callee && !SymName)
     return false;
 
   // Allow SelectionDAG isel to handle tail calls.
-  if (CI->isTailCall())
+  if (IsTailCall)
     return false;
 
-  // Obtain calling convention.
-  ImmutableCallSite CS(CI);
-  CallingConv::ID CC = CS.getCallingConv();
-
-  PointerType *PT = cast<PointerType>(CS.getCalledValue()->getType());
-  FunctionType *FTy = cast<FunctionType>(PT->getElementType());
-  bool IsVarArg = FTy->isVarArg();
-
-  // Not ready for varargs yet.
+  // Let SDISel handle vararg functions.
   if (IsVarArg)
     return false;
 
   // Handle simple calls for now, with legal return types and
   // those that can be extended.
-  Type *RetTy = I->getType();
+  Type *RetTy = CLI.RetTy;
   MVT RetVT;
   if (RetTy->isVoidTy())
     RetVT = MVT::isVoid;
@@ -1450,7 +1446,7 @@ bool PPCFastISel::SelectCall(const Instruction *I) {
 
   // Bail early if more than 8 arguments, as we only currently
   // handle arguments passed in registers.
-  unsigned NumArgs = CS.arg_size();
+  unsigned NumArgs = CLI.OutVals.size();
   if (NumArgs > 8)
     return false;
 
@@ -1465,28 +1461,16 @@ bool PPCFastISel::SelectCall(const Instruction *I) {
   ArgVTs.reserve(NumArgs);
   ArgFlags.reserve(NumArgs);
 
-  for (ImmutableCallSite::arg_iterator II = CS.arg_begin(), IE = CS.arg_end();
-       II != IE; ++II) {
-    // FIXME: ARM does something for intrinsic calls here, check into that.
-
-    unsigned AttrIdx = II - CS.arg_begin() + 1;
-    
+  for (unsigned i = 0, ie = NumArgs; i != ie; ++i) {
     // Only handle easy calls for now.  It would be reasonably easy
     // to handle <= 8-byte structures passed ByVal in registers, but we
     // have to ensure they are right-justified in the register.
-    if (CS.paramHasAttr(AttrIdx, Attribute::InReg) ||
-        CS.paramHasAttr(AttrIdx, Attribute::StructRet) ||
-        CS.paramHasAttr(AttrIdx, Attribute::Nest) ||
-        CS.paramHasAttr(AttrIdx, Attribute::ByVal))
+    ISD::ArgFlagsTy Flags = CLI.OutFlags[i];
+    if (Flags.isInReg() || Flags.isSRet() || Flags.isNest() || Flags.isByVal())
       return false;
 
-    ISD::ArgFlagsTy Flags;
-    if (CS.paramHasAttr(AttrIdx, Attribute::SExt))
-      Flags.setSExt();
-    if (CS.paramHasAttr(AttrIdx, Attribute::ZExt))
-      Flags.setZExt();
-
-    Type *ArgTy = (*II)->getType();
+    Value *ArgValue = CLI.OutVals[i];
+    Type *ArgTy = ArgValue->getType();
     MVT ArgVT;
     if (!isTypeLegal(ArgTy, ArgVT) && ArgVT != MVT::i16 && ArgVT != MVT::i8)
       return false;
@@ -1494,14 +1478,11 @@ bool PPCFastISel::SelectCall(const Instruction *I) {
     if (ArgVT.isVector())
       return false;
 
-    unsigned Arg = getRegForValue(*II);
+    unsigned Arg = getRegForValue(ArgValue);
     if (Arg == 0)
       return false;
 
-    unsigned OriginalAlignment = DL.getABITypeAlignment(ArgTy);
-    Flags.setOrigAlign(OriginalAlignment);
-
-    Args.push_back(*II);
+    Args.push_back(ArgValue);
     ArgRegs.push_back(Arg);
     ArgVTs.push_back(ArgVT);
     ArgFlags.push_back(Flags);
@@ -1515,18 +1496,28 @@ bool PPCFastISel::SelectCall(const Instruction *I) {
                        RegArgs, CC, NumBytes, IsVarArg))
     return false;
 
+  MachineInstrBuilder MIB;
   // FIXME: No handling for function pointers yet.  This requires
   // implementing the function descriptor (OPD) setup.
   const GlobalValue *GV = dyn_cast<GlobalValue>(Callee);
-  if (!GV)
-    return false;
-
-  // Build direct call with NOP for TOC restore.
-  // FIXME: We can and should optimize away the NOP for local calls.
-  MachineInstrBuilder MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
-                                    TII.get(PPC::BL8_NOP));
-  // Add callee.
-  MIB.addGlobalAddress(GV);
+  if (!GV) {
+    // patchpoints are a special case; they always dispatch to a pointer value.
+    // However, we don't actually want to generate the indirect call sequence
+    // here (that will be generated, as necessary, during asm printing), and
+    // the call we generate here will be erased by FastISel::selectPatchpoint,
+    // so don't try very hard...
+    if (CLI.IsPatchPoint)
+      MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(PPC::NOP));
+    else
+      return false;
+  } else {
+    // Build direct call with NOP for TOC restore.
+    // FIXME: We can and should optimize away the NOP for local calls.
+    MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
+                  TII.get(PPC::BL8_NOP));
+    // Add callee.
+    MIB.addGlobalAddress(GV);
+  }
 
   // Add implicit physical register uses to the call.
   for (unsigned II = 0, IE = RegArgs.size(); II != IE; ++II)
@@ -1540,14 +1531,10 @@ bool PPCFastISel::SelectCall(const Instruction *I) {
   // defs for return values will be added by setPhysRegsDeadExcept().
   MIB.addRegMask(TRI.getCallPreservedMask(CC));
 
-  // Finish off the call including any return values.
-  SmallVector<unsigned, 4> UsedRegs;
-  finishCall(RetVT, UsedRegs, I, CC, NumBytes, IsVarArg);
-
-  // Set all unused physregs defs as dead.
-  static_cast<MachineInstr *>(MIB)->setPhysRegsDeadExcept(UsedRegs, TRI);
+  CLI.Call = MIB;
 
-  return true;
+  // Finish off the call including any return values.
+  return finishCall(RetVT, CLI, NumBytes);
 }
 
 // Attempt to fast-select a return instruction.
@@ -1837,9 +1824,7 @@ bool PPCFastISel::fastSelectInstruction(const Instruction *I) {
     case Instruction::Sub:
       return SelectBinaryIntOp(I, ISD::SUB);
     case Instruction::Call:
-      if (dyn_cast<IntrinsicInst>(I))
-        return false;
-      return SelectCall(I);
+      return selectCall(I);
     case Instruction::Ret:
       return SelectRet(I);
     case Instruction::Trunc: