# HG changeset patch
# User Andreas Woess <andreas.woess@jku.at>
# Date 1327832838 -3600
# Node ID b197bbb58d2fa05725cdb055e954c9ab90353c6d
# Parent  5caca26cb1b9837823f484f38ed70c24145683e2
Fix and improve tail call.

Fix flagsFor: Allow more than one input.
Inputs and temporaries may only be registers.
Remove redundant moves from emitCode, these are emitted by visitInvokeArguments in TailcallNode.
Skip over empty slot for two-slot values in frame state.

diff -r 5caca26cb1b9 -r b197bbb58d2f graal/com.oracle.max.graal.hotspot/src/com/oracle/max/graal/hotspot/nodes/TailcallNode.java
--- a/graal/com.oracle.max.graal.hotspot/src/com/oracle/max/graal/hotspot/nodes/TailcallNode.java	Fri Jan 27 17:36:06 2012 +0100
+++ b/graal/com.oracle.max.graal.hotspot/src/com/oracle/max/graal/hotspot/nodes/TailcallNode.java	Sun Jan 29 11:27:18 2012 +0100
@@ -30,6 +30,7 @@
 import com.oracle.max.graal.compiler.gen.*;
 import com.oracle.max.graal.hotspot.*;
 import com.oracle.max.graal.hotspot.target.amd64.*;
+import com.oracle.max.graal.java.*;
 import com.oracle.max.graal.nodes.*;
 import com.oracle.max.graal.nodes.spi.*;
 import com.oracle.max.graal.nodes.type.*;
@@ -62,10 +63,10 @@
 
         CiKind[] signature = CiUtil.signatureToKinds(method.signature(), isStatic ? null : method.holder().kind(true));
         CiCallingConvention cc = gen.frameMap().registerConfig.getCallingConvention(CiCallingConvention.Type.JavaCall, signature, gen.target(), false);
-        gen.frameMap().callsMethod(cc, CiCallingConvention.Type.JavaCall);
+        gen.frameMap().callsMethod(cc, CiCallingConvention.Type.JavaCall); // TODO (aw): I think this is unnecessary for a tail call.
         List<ValueNode> parameters = new ArrayList<>();
-        for (int i = 0; i < cc.locations.length; i++) {
-            parameters.add(frameState.localAt(i));
+        for (int i = 0, slot = 0; i < cc.locations.length; i++, slot += FrameStateBuilder.stackSlots(frameState.localAt(slot).kind())) {
+            parameters.add(frameState.localAt(slot));
         }
         List<CiValue> argList = gen.visitInvokeArguments(cc, parameters, null);
 
diff -r 5caca26cb1b9 -r b197bbb58d2f graal/com.oracle.max.graal.hotspot/src/com/oracle/max/graal/hotspot/target/amd64/AMD64TailcallOp.java
--- a/graal/com.oracle.max.graal.hotspot/src/com/oracle/max/graal/hotspot/target/amd64/AMD64TailcallOp.java	Fri Jan 27 17:36:06 2012 +0100
+++ b/graal/com.oracle.max.graal.hotspot/src/com/oracle/max/graal/hotspot/target/amd64/AMD64TailcallOp.java	Sun Jan 29 11:27:18 2012 +0100
@@ -37,9 +37,15 @@
  * Performs a hard-coded tail call to the specified target, which normally should be an RiCompiledCode instance.
  */
 public class AMD64TailcallOp extends AMD64LIRInstruction {
+
     public AMD64TailcallOp(List<CiValue> parameters, CiValue target, CiValue[] callingConvention) {
         super("TAILCALL", LIRInstruction.NO_OPERANDS, null, toArray(parameters, target), LIRInstruction.NO_OPERANDS, callingConvention.clone());
         assert inputs.length == temps.length + 1;
+
+        for (int i = 0; i < temps.length; i++) {
+            assert isRegister(temps[i]) : "too many parameters for tail call";
+            assert sameRegister(temps[i], inputs[i]) : "inputs do not match calling convention";
+        }
     }
 
     private static CiValue[] toArray(List<CiValue> parameters, CiValue target) {
@@ -51,19 +57,6 @@
 
     @Override
     public void emitCode(TargetMethodAssembler tasm, AMD64MacroAssembler masm) {
-        // move all parameters to the correct positions, according to the calling convention
-        // TODO: These moves should not be part of the TAILCALL opcode, but emitted as separate MOVE instructions before.
-        for (int i = 0; i < inputs.length - 1; i++) {
-            assert inputs[i].kind == CiKind.Object || inputs[i].kind == CiKind.Int || inputs[i].kind == CiKind.Long : "only Object, int and long supported for now";
-            assert isRegister(temps[i]) : "too many parameters";
-            if (isRegister(inputs[i])) {
-                if (inputs[i] != temps[i]) {
-                    masm.movq(asRegister(temps[i]), asRegister(inputs[i]));
-                }
-            } else {
-                masm.movq(asRegister(temps[i]), tasm.asAddress(inputs[i]));
-            }
-        }
         // destroy the current frame (now the return address is the top of stack)
         masm.leave();
 
@@ -74,10 +67,10 @@
 
     @Override
     protected EnumSet<OperandFlag> flagsFor(OperandMode mode, int index) {
-        if (mode == OperandMode.Input && index == 0) {
-            return EnumSet.of(OperandFlag.Register, OperandFlag.Constant, OperandFlag.Stack);
-        } else if (mode == OperandMode.Temp && index == 0) {
-            return EnumSet.of(OperandFlag.Register, OperandFlag.Stack);
+        if (mode == OperandMode.Input) {
+            return EnumSet.of(OperandFlag.Register);
+        } else if (mode == OperandMode.Temp) {
+            return EnumSet.of(OperandFlag.Register);
         }
         throw Util.shouldNotReachHere();
     }