Lower stackmap intrinsics directly to their target opcode in the DAG builder.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193769 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 216 insertions, 11 deletions

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 88572b5..69c82d4 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -5309,6 +5309,15 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
   case Intrinsic::donothing:
     // ignore
     return 0;
+  case Intrinsic::experimental_stackmap: {
+    visitStackmap(I);
+    return 0;
+  }
+  case Intrinsic::experimental_patchpoint_void:
+  case Intrinsic::experimental_patchpoint_i64: {
+    visitPatchpoint(I);
+    return 0;
+  }
   }
 }
 
@@ -5373,15 +5382,8 @@ void SelectionDAGBuilder::LowerCallTo(ImmutableCallSite CS, SDValue Callee,
     SDValue ArgNode = getValue(V);
     Entry.Node = ArgNode; Entry.Ty = V->getType();
 
-    unsigned attrInd = i - CS.arg_begin() + 1;
-    Entry.isSExt     = CS.paramHasAttr(attrInd, Attribute::SExt);
-    Entry.isZExt     = CS.paramHasAttr(attrInd, Attribute::ZExt);
-    Entry.isInReg    = CS.paramHasAttr(attrInd, Attribute::InReg);
-    Entry.isSRet     = CS.paramHasAttr(attrInd, Attribute::StructRet);
-    Entry.isNest     = CS.paramHasAttr(attrInd, Attribute::Nest);
-    Entry.isByVal    = CS.paramHasAttr(attrInd, Attribute::ByVal);
-    Entry.isReturned = CS.paramHasAttr(attrInd, Attribute::Returned);
-    Entry.Alignment  = CS.getParamAlignment(attrInd);
+    // Skip the first return-type Attribute to get to params.
+    Entry.setAttributes(&CS, i - CS.arg_begin() + 1);
     Args.push_back(Entry);
   }
 
@@ -5463,8 +5465,8 @@ void SelectionDAGBuilder::LowerCallTo(ImmutableCallSite CS, SDValue Callee,
   }
 
   if (!Result.second.getNode()) {
-    // As a special case, a null chain means that a tail call has been emitted and
-    // the DAG root is already updated.
+    // As a special case, a null chain means that a tail call has been emitted
+    // and the DAG root is already updated.
     HasTailCall = true;
 
     // Since there's no actual continuation from this block, nothing can be
@@ -6721,6 +6723,189 @@ void SelectionDAGBuilder::visitVACopy(const CallInst &I) {
                           DAG.getSrcValue(I.getArgOperand(1))));
 }
 
+/// \brief Lower an argument list according to the target calling convention.
+///
+/// \return A tuple of <return-value, token-chain>
+///
+/// This is a helper for lowering intrinsics that follow a target calling
+/// convention or require stack pointer adjustment. Only a subset of the
+/// intrinsic's operands need to participate in the calling convention.
+std::pair<SDValue, SDValue>
+SelectionDAGBuilder::LowerCallOperands(const CallInst &CI, unsigned ArgIdx,
+                                       unsigned NumArgs, SDValue Callee) {
+  TargetLowering::ArgListTy Args;
+  Args.reserve(NumArgs);
+
+  // Populate the argument list.
+  // Attributes for args start at offset 1, after the return attribute.
+  ImmutableCallSite CS(&CI);
+  for (unsigned ArgI = ArgIdx, ArgE = ArgIdx + NumArgs, AttrI = ArgIdx + 1;
+       ArgI != ArgE; ++ArgI) {
+    const Value *V = CI.getOperand(ArgI);
+
+    assert(!V->getType()->isEmptyTy() && "Empty type passed to intrinsic.");
+
+    TargetLowering::ArgListEntry Entry;
+    Entry.Node = getValue(V);
+    Entry.Ty = V->getType();
+    Entry.setAttributes(&CS, AttrI);
+    Args.push_back(Entry);
+  }
+
+  TargetLowering::CallLoweringInfo CLI(getRoot(), CI.getType(),
+    /*retSExt*/ false, /*retZExt*/ false, /*isVarArg*/ false, /*isInReg*/ false,
+    NumArgs, CI.getCallingConv(), /*isTailCall*/ false, /*doesNotReturn*/ false,
+    /*isReturnValueUsed*/ CI.use_empty(), Callee, Args, DAG, getCurSDLoc());
+
+  const TargetLowering *TLI = TM.getTargetLowering();
+  return TLI->LowerCallTo(CLI);
+}
+
+/// \brief Lower llvm.experimental.stackmap directly to its target opcode.
+void SelectionDAGBuilder::visitStackmap(const CallInst &CI) {
+  // void @llvm.experimental.stackmap(i32 <id>, i32 <numShadowBytes>,
+  //                                  [live variables...])
+
+  assert(CI.getType()->isVoidTy() && "Stackmap cannot return a value.");
+
+  SDValue Callee = getValue(CI.getCalledValue());
+
+  // Lower into a call sequence with no args and no return value.
+  std::pair<SDValue, SDValue> Result = LowerCallOperands(CI, 0, 0, Callee);
+  // Set the root to the target-lowered call chain.
+  SDValue Chain = Result.second;
+  DAG.setRoot(Chain);
+
+  /// Get a call instruction from the call sequence chain.
+  /// Tail calls are not allowed.
+  SDNode *CallEnd = Chain.getNode();
+  assert(CallEnd->getOpcode() == ISD::CALLSEQ_END &&
+         "Expected a callseq node.");
+  SDNode *Call = CallEnd->getOperand(0).getNode();
+  bool hasGlue = Call->getGluedNode();
+
+  assert(Call->getNumOperands() == hasGlue ? 2 : 1 &&
+         "Unexpected extra stackmap call arguments.");
+
+  // Replace the target specific call node with the stackmap intrinsic.
+  SmallVector<SDValue, 8> Ops;
+
+  // Add the <id> and <numShadowBytes> constants.
+  for (unsigned i = 0; i < 2; ++i) {
+    SDValue tmp = getValue(CI.getOperand(i));
+    Ops.push_back(DAG.getTargetConstant(
+        cast<ConstantSDNode>(tmp)->getZExtValue(), MVT::i32));
+  }
+  // Push live variables for the stack map.
+  for (unsigned i = 2, e = CI.getNumArgOperands(); i != e; ++i)
+    Ops.push_back(getValue(CI.getArgOperand(i)));
+
+  // Push the chain (this is originally the first operand of the call, but
+  // becomes now the last or second to last operand).
+  Ops.push_back(*(Call->op_begin()));
+
+    // Push the glue flag (last operand).
+  if (hasGlue)
+    Ops.push_back(*(Call->op_end()-1));
+
+  // Replace the target specific call node with STACKMAP in-place. This way we
+  // don't have to call ReplaceAllUsesWith and STACKMAP will take the call's
+  // place in the chain.
+  SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
+  DAG.SelectNodeTo(Call, TargetOpcode::STACKMAP, NodeTys, &Ops[0], Ops.size());
+}
+
+/// \brief Lower llvm.experimental.patchpoint directly to its target opcode.
+void SelectionDAGBuilder::visitPatchpoint(const CallInst &CI) {
+  // void|i64 @llvm.experimental.patchpoint.void|i64(i32 <id>,
+  //                                           i32 <numNopBytes>,
+  //                                           i8* <target>, i32 <numArgs>,
+  //                                           [Args...], [live variables...])
+
+  SDValue Callee = getValue(CI.getOperand(2)); // <target>
+
+  // Get the real number of arguments participating in the call <numArgs>
+  unsigned NumArgs =
+      cast<ConstantSDNode>(getValue(CI.getArgOperand(3)))->getZExtValue();
+
+  // Skip the four meta args: <id>, <numNopBytes>, <target>, <numArgs>
+  assert(CI.getNumArgOperands() >= NumArgs + 4 &&
+         "Not enough arguments provided to the patchpoint intrinsic");
+
+  std::pair<SDValue, SDValue> Result =
+    LowerCallOperands(CI, 4, NumArgs, Callee);
+  // Set the root to the target-lowered call chain.
+  SDValue Chain = Result.second;
+  DAG.setRoot(Chain);
+
+  SDNode *CallEnd = Chain.getNode();
+  if (!CI.getType()->isVoidTy()) {
+    setValue(&CI, Result.first);
+    if (CallEnd->getOpcode() == ISD::CopyFromReg)
+      CallEnd = CallEnd->getOperand(0).getNode();
+  }
+  /// Get a call instruction from the call sequence chain.
+  /// Tail calls are not allowed.
+  assert(CallEnd->getOpcode() == ISD::CALLSEQ_END &&
+         "Expected a callseq node.");
+  SDNode *Call = CallEnd->getOperand(0).getNode();
+  bool hasGlue = Call->getGluedNode();
+
+  // Replace the target specific call node with the patchable intrinsic.
+  SmallVector<SDValue, 8> Ops;
+
+  // Add the <id> and <numNopBytes> constants.
+  for (unsigned i = 0; i < 2; ++i) {
+    SDValue tmp = getValue(CI.getOperand(i));
+    Ops.push_back(DAG.getTargetConstant(
+        cast<ConstantSDNode>(tmp)->getZExtValue(), MVT::i32));
+  }
+  // Assume that the Callee is a constant address.
+  Ops.push_back(
+    DAG.getIntPtrConstant(cast<ConstantSDNode>(Callee)->getZExtValue()));
+
+  // Adjust <numArgs> to account for any stack arguments.
+  // Call Node: Chain, Target, {Args}, RegMask, [Glue]
+  unsigned NumCallArgs = Call->getNumOperands() - (hasGlue ? 4 : 3);
+  Ops.push_back(DAG.getTargetConstant(NumCallArgs, MVT::i32));
+
+  // Push the arguments from the call instruction.
+  SDNode::op_iterator e = hasGlue ? Call->op_end()-2 : Call->op_end()-1;
+  for (SDNode::op_iterator i = Call->op_begin()+2; i != e; ++i)
+    Ops.push_back(*i);
+
+  // Push live variables for the stack map.
+  for (unsigned i = NumArgs + 4, e = CI.getNumArgOperands(); i != e; ++i) {
+    SDValue OpVal = getValue(CI.getArgOperand(i));
+    if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(OpVal)) {
+      Ops.push_back(
+        DAG.getTargetConstant(C->getSExtValue(), MVT::i64));
+    } else
+      Ops.push_back(OpVal);
+  }
+
+  // Push the register mask info.
+  if (hasGlue)
+    Ops.push_back(*(Call->op_end()-2));
+  else
+    Ops.push_back(*(Call->op_end()-1));
+
+  // Push the chain (this is originally the first operand of the call, but
+  // becomes now the last or second to last operand).
+  Ops.push_back(*(Call->op_begin()));
+
+  // Push the glue flag (last operand).
+  if (hasGlue)
+    Ops.push_back(*(Call->op_end()-1));
+
+  // Replace the target specific call node with PATCHPOINT in-place. This
+  // way we don't have to call ReplaceAllUsesWith and PATCHPOINT will
+  // take the call's place in the chain.
+  SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
+  DAG.SelectNodeTo(Call, TargetOpcode::PATCHPOINT, NodeTys, &Ops[0],
+                   Ops.size());
+}
+
 /// TargetLowering::LowerCallTo - This is the default LowerCallTo
 /// implementation, which just calls LowerCall.
 /// FIXME: When all targets are
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
index 17a735b..6ecf5a0 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
@@ -619,6 +619,11 @@ public:
   void LowerCallTo(ImmutableCallSite CS, SDValue Callee, bool IsTailCall,
                    MachineBasicBlock *LandingPad = NULL);
 
+  std::pair<SDValue, SDValue> LowerCallOperands(const CallInst &CI,
+                                                unsigned ArgIdx,
+                                                unsigned NumArgs,
+                                                SDValue Callee);
+
   /// UpdateSplitBlock - When an MBB was split during scheduling, update the
   /// references that ned to refer to the last resulting block.
   void UpdateSplitBlock(MachineBasicBlock *First, MachineBasicBlock *Last);
@@ -752,6 +757,8 @@ private:
   void visitVAArg(const VAArgInst &I);
   void visitVAEnd(const CallInst &I);
   void visitVACopy(const CallInst &I);
+  void visitStackmap(const CallInst &I);
+  void visitPatchpoint(const CallInst &I);
 
   void visitUserOp1(const Instruction &I) {
     llvm_unreachable("UserOp1 should not exist at instruction selection time!");
diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 4d30e7b..82b068d 100644
--- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -64,6 +64,19 @@ bool TargetLowering::isInTailCallPosition(SelectionDAG &DAG, SDNode *Node,
   return isUsedByReturnOnly(Node, Chain);
 }
 
+/// \brief Set CallLoweringInfo attribute flags based on a call instruction
+/// and called function attributes.
+void TargetLowering::ArgListEntry::setAttributes(ImmutableCallSite *CS,
+                                                 unsigned AttrIdx) {
+  isSExt     = CS->paramHasAttr(AttrIdx, Attribute::SExt);
+  isZExt     = CS->paramHasAttr(AttrIdx, Attribute::ZExt);
+  isInReg    = CS->paramHasAttr(AttrIdx, Attribute::InReg);
+  isSRet     = CS->paramHasAttr(AttrIdx, Attribute::StructRet);
+  isNest     = CS->paramHasAttr(AttrIdx, Attribute::Nest);
+  isByVal    = CS->paramHasAttr(AttrIdx, Attribute::ByVal);
+  isReturned = CS->paramHasAttr(AttrIdx, Attribute::Returned);
+  Alignment  = CS->getParamAlignment(AttrIdx);
+}
 
 /// Generate a libcall taking the given operands as arguments and returning a
 /// result of type RetVT.