Second installment of "BasicBlock operands to the back"

changes.

For InvokeInst now all arguments begin at op_begin().
The Callee, Cont and Fail are now faster to get by
access relative to op_end().

This patch introduces some temporary uglyness in CallSite.
Next I'll bring CallInst up to a similar scheme and then
the uglyness will magically vanish.

This patch also exposes all the reliance of the libraries
on InvokeInst's operand ordering. I am thinking of taking
care of that too.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66920 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/CallSite.h

@@ -119,7 +119,7 @@ public:
   ///
   Value *getCalledValue() const {
     assert(getInstruction() && "Not a call or invoke instruction!");
-    return getInstruction()->getOperand(0);
+    return *getCallee();
   }
 
   /// getCalledFunction - Return the function being called if this is a direct
@@ -133,7 +133,7 @@ public:
   ///
   void setCalledFunction(Value *V) {
     assert(getInstruction() && "Not a call or invoke instruction!");
-    getInstruction()->setOperand(0, V);
+    *getCallee() = V;
   }
 
   Value *getArgument(unsigned ArgNo) const {
@@ -147,6 +147,16 @@ public:
     getInstruction()->setOperand(getArgumentOffset() + ArgNo, newVal);
   }
 
+  /// Given a value use iterator, returns the argument that corresponds to it.
+  /// Iterator must actually correspond to an argument.
+  unsigned getArgumentNo(Value::use_iterator I) const {
+    assert(getInstruction() && "Not a call or invoke instruction!");
+    assert(arg_begin() <= &I.getUse() && &I.getUse() < arg_end()
+           && "Argument # out of range!");
+
+    return &I.getUse() - arg_begin();
+  }
+
   /// Given an operand number, returns the argument that corresponds to it.
   /// OperandNo must be a valid operand number that actually corresponds to an
   /// argument.
@@ -172,7 +182,7 @@ public:
     return getInstruction()->op_begin() + getArgumentOffset();
   }
 
-  arg_iterator arg_end() const { return getInstruction()->op_end(); }
+  arg_iterator arg_end() const { return getInstruction()->op_end() - getArgumentEndOffset(); }
   bool arg_empty() const { return arg_end() == arg_begin(); }
   unsigned arg_size() const { return unsigned(arg_end() - arg_begin()); }
 
@@ -181,17 +191,25 @@ public:
   }
 
   bool isCallee(Value::use_iterator UI) const {
-    return getInstruction()->op_begin() == &UI.getUse();
+    return getCallee() == &UI.getUse();
   }
-
 private:
   /// Returns the operand number of the first argument
   unsigned getArgumentOffset() const {
     if (isCall())
       return 1; // Skip Function
     else
-      return 3; // Skip Function, BB, BB
+      return 0; // Args are at the front
   }
+
+  unsigned getArgumentEndOffset() const {
+    if (isCall())
+      return 0; // Unchanged
+    else
+      return 3; // Skip BB, BB, Function
+  }
+
+  User::op_iterator getCallee() const;
 };
 
 } // End llvm namespace