Refine allocation policy for input operands at calls.

For instructions that are marked as calls we can use:

1. Fixed input registers

2. Use-at-start policy (register, memory or constant).

(Memory or constant would not need the use-at-start policy, but
not specifying use-at-start prevents the allocator from using
a register even if there is one available. That's why use-at-start
is required and guarded by assertion)
Review URL: http://codereview.chromium.org/6853010

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7616 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/lithium-arm.cc

@@ -61,22 +61,21 @@ void LOsrEntry::MarkSpilledRegister(int allocation_index,
 
 #ifdef DEBUG
 void LInstruction::VerifyCall() {
-  // Call instructions can use only fixed registers as
-  // temporaries and outputs because all registers
-  // are blocked by the calling convention.
-  // Inputs must use a fixed register.
+  // Call instructions can use only fixed registers as temporaries and
+  // outputs because all registers are blocked by the calling convention.
+  // Inputs operands must use a fixed register or use-at-start policy or
+  // a non-register policy.
   ASSERT(Output() == NULL ||
          LUnallocated::cast(Output())->HasFixedPolicy() ||
          !LUnallocated::cast(Output())->HasRegisterPolicy());
   for (UseIterator it(this); it.HasNext(); it.Advance()) {
-    LOperand* operand = it.Next();
-    ASSERT(LUnallocated::cast(operand)->HasFixedPolicy() ||
-           !LUnallocated::cast(operand)->HasRegisterPolicy());
+    LUnallocated* operand = LUnallocated::cast(it.Next());
+    ASSERT(operand->HasFixedPolicy() ||
+           operand->IsUsedAtStart());
   }
   for (TempIterator it(this); it.HasNext(); it.Advance()) {
-    LOperand* operand = it.Next();
-    ASSERT(LUnallocated::cast(operand)->HasFixedPolicy() ||
-           !LUnallocated::cast(operand)->HasRegisterPolicy());
+    LUnallocated* operand = LUnallocated::cast(it.Next());
+    ASSERT(operand->HasFixedPolicy() ||!operand->HasRegisterPolicy());
   }
 }
 #endif

src/ia32/lithium-ia32.cc

@@ -71,22 +71,21 @@ void LOsrEntry::MarkSpilledDoubleRegister(int allocation_index,
 
 #ifdef DEBUG
 void LInstruction::VerifyCall() {
-  // Call instructions can use only fixed registers as
-  // temporaries and outputs because all registers
-  // are blocked by the calling convention.
-  // Inputs must use a fixed register.
+  // Call instructions can use only fixed registers as temporaries and
+  // outputs because all registers are blocked by the calling convention.
+  // Inputs operands must use a fixed register or use-at-start policy or
+  // a non-register policy.
   ASSERT(Output() == NULL ||
          LUnallocated::cast(Output())->HasFixedPolicy() ||
          !LUnallocated::cast(Output())->HasRegisterPolicy());
   for (UseIterator it(this); it.HasNext(); it.Advance()) {
-    LOperand* operand = it.Next();
-    ASSERT(LUnallocated::cast(operand)->HasFixedPolicy() ||
-           !LUnallocated::cast(operand)->HasRegisterPolicy());
+    LUnallocated* operand = LUnallocated::cast(it.Next());
+    ASSERT(operand->HasFixedPolicy() ||
+           operand->IsUsedAtStart());
   }
   for (TempIterator it(this); it.HasNext(); it.Advance()) {
-    LOperand* operand = it.Next();
-    ASSERT(LUnallocated::cast(operand)->HasFixedPolicy() ||
-           !LUnallocated::cast(operand)->HasRegisterPolicy());
+    LUnallocated* operand = LUnallocated::cast(it.Next());
+    ASSERT(operand->HasFixedPolicy() ||!operand->HasRegisterPolicy());
   }
 }
 #endif
@@ -2046,7 +2045,8 @@ LInstruction* LChunkBuilder::DoFunctionLiteral(HFunctionLiteral* instr) {
 
 LInstruction* LChunkBuilder::DoDeleteProperty(HDeleteProperty* instr) {
   LDeleteProperty* result =
-      new LDeleteProperty(Use(instr->object()), UseOrConstant(instr->key()));
+      new LDeleteProperty(UseAtStart(instr->object()),
+                          UseOrConstantAtStart(instr->key()));
   return MarkAsCall(DefineFixed(result, eax), instr);
 }
 

src/x64/lithium-x64.cc

@@ -71,22 +71,21 @@ void LOsrEntry::MarkSpilledDoubleRegister(int allocation_index,
 
 #ifdef DEBUG
 void LInstruction::VerifyCall() {
-  // Call instructions can use only fixed registers as
-  // temporaries and outputs because all registers
-  // are blocked by the calling convention.
-  // Inputs must use a fixed register.
+  // Call instructions can use only fixed registers as temporaries and
+  // outputs because all registers are blocked by the calling convention.
+  // Inputs operands must use a fixed register or use-at-start policy or
+  // a non-register policy.
   ASSERT(Output() == NULL ||
          LUnallocated::cast(Output())->HasFixedPolicy() ||
          !LUnallocated::cast(Output())->HasRegisterPolicy());
   for (UseIterator it(this); it.HasNext(); it.Advance()) {
-    LOperand* operand = it.Next();
-    ASSERT(LUnallocated::cast(operand)->HasFixedPolicy() ||
-           !LUnallocated::cast(operand)->HasRegisterPolicy());
+    LUnallocated* operand = LUnallocated::cast(it.Next());
+    ASSERT(operand->HasFixedPolicy() ||
+           operand->IsUsedAtStart());
   }
   for (TempIterator it(this); it.HasNext(); it.Advance()) {
-    LOperand* operand = it.Next();
-    ASSERT(LUnallocated::cast(operand)->HasFixedPolicy() ||
-           !LUnallocated::cast(operand)->HasRegisterPolicy());
+    LUnallocated* operand = LUnallocated::cast(it.Next());
+    ASSERT(operand->HasFixedPolicy() ||!operand->HasRegisterPolicy());
   }
 }
 #endif
@@ -1984,7 +1983,8 @@ LInstruction* LChunkBuilder::DoFunctionLiteral(HFunctionLiteral* instr) {
 
 LInstruction* LChunkBuilder::DoDeleteProperty(HDeleteProperty* instr) {
   LDeleteProperty* result =
-      new LDeleteProperty(Use(instr->object()), UseOrConstant(instr->key()));
+      new LDeleteProperty(UseAtStart(instr->object()),
+                          UseOrConstantAtStart(instr->key()));
   return MarkAsCall(DefineFixed(result, rax), instr);
 }