From 2bc210d99f5a7322a1ae84775eba351d9ab6ea85 Mon Sep 17 00:00:00 2001
From: Jim Laskey <jlaskey@mac.com>
Date: Thu, 22 Feb 2007 15:37:19 +0000
Subject: [PATCH] Simplify lowering and selection of exception ops.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34491 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Target/TargetLowering.h     | 38 ++++++++++++++++++++++++
 lib/CodeGen/SelectionDAG/LegalizeDAG.cpp | 28 +++++++++++++++--
 2 files changed, 64 insertions(+), 2 deletions(-)

diff --git a/include/llvm/Target/TargetLowering.h b/include/llvm/Target/TargetLowering.h
index b52b68c9dc6..5aae2583cef 100644
--- a/include/llvm/Target/TargetLowering.h
+++ b/include/llvm/Target/TargetLowering.h
@@ -403,6 +403,20 @@ public:
     return StackPointerRegisterToSaveRestore;
   }
 
+  /// getExceptionAddressRegister - If a physical register, this returns
+  /// the register that receives the exception address on entry to a landing
+  /// pad.
+  unsigned getExceptionAddressRegister() const {
+    return ExceptionPointerRegister;
+  }
+
+  /// getExceptionSelectorRegister - If a physical register, this returns
+  /// the register that receives the exception typeid on entry to a landing
+  /// pad.
+  unsigned getExceptionSelectorRegister() const {
+    return ExceptionSelectorRegister;
+  }
+
   /// getJumpBufSize - returns the target's jmp_buf size in bytes (if never
   /// set, the default is 200)
   unsigned getJumpBufSize() const {
@@ -604,6 +618,20 @@ protected:
     StackPointerRegisterToSaveRestore = R;
   }
   
+  /// setExceptionPointerRegister - If set to a physical register, this sets
+  /// the register that receives the exception address on entry to a landing
+  /// pad.
+  void setExceptionPointerRegister(unsigned R) {
+    ExceptionPointerRegister = R;
+  }
+
+  /// setExceptionSelectorRegister - If set to a physical register, this sets
+  /// the register that receives the exception typeid on entry to a landing
+  /// pad.
+  void setExceptionSelectorRegister(unsigned R) {
+    ExceptionSelectorRegister = R;
+  }
+
   /// SelectIsExpensive - Tells the code generator not to expand operations
   /// into sequences that use the select operations if possible.
   void setSelectIsExpensive() { SelectIsExpensive = true; }
@@ -956,6 +984,16 @@ private:
   /// and restore.
   unsigned StackPointerRegisterToSaveRestore;
 
+  /// ExceptionPointerRegister - If set to a physical register, this specifies
+  /// the register that receives the exception address on entry to a landing
+  /// pad.
+  unsigned ExceptionPointerRegister;
+
+  /// ExceptionSelectorRegister - If set to a physical register, this specifies
+  /// the register that receives the exception typeid on entry to a landing
+  /// pad.
+  unsigned ExceptionSelectorRegister;
+
   /// RegClassForVT - This indicates the default register class to use for
   /// each ValueType the target supports natively.
   TargetRegisterClass *RegClassForVT[MVT::LAST_VALUETYPE];
diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 0992e421b1b..d9bb99ec27d 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -668,8 +668,6 @@ SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) {
     break;
   case ISD::FRAMEADDR:
   case ISD::RETURNADDR:
-  case ISD::EXCEPTIONADDR:
-  case ISD::EHSELECTION:
     // The only option for these nodes is to custom lower them.  If the target
     // does not custom lower them, then return zero.
     Tmp1 = TLI.LowerOperation(Op, DAG);
@@ -678,6 +676,32 @@ SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) {
     else
       Result = DAG.getConstant(0, TLI.getPointerTy());
     break;
+  case ISD::EHSELECTION:
+    LegalizeOp(Node->getOperand(1));
+    // Fall Thru
+  case ISD::EXCEPTIONADDR: {
+    Tmp1 = LegalizeOp(Node->getOperand(0));
+    MVT::ValueType VT = Node->getValueType(0);
+    switch (TLI.getOperationAction(Node->getOpcode(), VT)) {
+    default: assert(0 && "This action is not supported yet!");
+    case TargetLowering::Expand: {
+        unsigned Reg = Node->getOpcode() == ISD::EXCEPTIONADDR ?
+                          TLI.getExceptionAddressRegister() :
+                          TLI.getExceptionSelectorRegister();
+        Result = DAG.getCopyFromReg(Tmp1, Reg, VT).getValue(Op.ResNo);
+      }
+      break;
+    case TargetLowering::Custom:
+      Result = TLI.LowerOperation(Op, DAG);
+      if (Result.Val) break;
+      // Fall Thru
+    case TargetLowering::Legal:
+      Result = DAG.getNode(ISD::MERGE_VALUES, VT, DAG.getConstant(0, VT), Tmp1).
+                  getValue(Op.ResNo);
+      break;
+    }
+    }
+    break;
   case ISD::AssertSext:
   case ISD::AssertZext:
     Tmp1 = LegalizeOp(Node->getOperand(0));