Make it more pleasant to work with expression locations in the...

src/ia32/fast-codegen-ia32.cc

 // Copyright 2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 90 matching lines @@
     __ RecordJSReturn();
     // Do not use the leave instruction here because it is too short to
     // patch with the code required by the debugger.
     __ mov(esp, ebp);
     __ pop(ebp);
     __ ret((fun->scope()->num_parameters() + 1) * kPointerSize);
   }
 }
 
 
+void FastCodeGenerator::Move(Location destination, Slot* source) {
+  switch (destination.type()) {
+    case Location::NOWHERE:
+      break;
+    case Location::TEMP:
+      __ push(Operand(ebp, SlotOffset(source)));
+      break;
+  }
+}
+
+
+void FastCodeGenerator::Move(Location destination, Literal* expr) {
+  switch (destination.type()) {
+    case Location::NOWHERE:
+      break;
+    case Location::TEMP:
+      __ push(Immediate(expr->handle()));
+      break;
+  }
+}
+
+
+void FastCodeGenerator::Move(Slot* destination, Location source) {
+  switch (source.type()) {
+    case Location::NOWHERE:
+      UNREACHABLE();
+    case Location::TEMP:
+      __ pop(Operand(ebp, SlotOffset(destination)));
+      break;
+  }
+}
+
+
 void FastCodeGenerator::DeclareGlobals(Handle<FixedArray> pairs) {
   // Call the runtime to declare the globals.
   __ push(esi);  // The context is the first argument.
   __ push(Immediate(pairs));
   __ push(Immediate(Smi::FromInt(is_eval_ ? 1 : 0)));
   __ CallRuntime(Runtime::kDeclareGlobals, 3);
   // Return value is ignored.
 }
 
 
-void FastCodeGenerator::VisitBlock(Block* stmt) {
-  Comment cmnt(masm_, "[ Block");
-  SetStatementPosition(stmt);
-  VisitStatements(stmt->statements());
-}
-
-
-void FastCodeGenerator::VisitExpressionStatement(ExpressionStatement* stmt) {
-  Comment cmnt(masm_, "[ ExpressionStatement");
-  SetStatementPosition(stmt);
-  Visit(stmt->expression());
-}
-
-
 void FastCodeGenerator::VisitReturnStatement(ReturnStatement* stmt) {
   Comment cmnt(masm_, "[ ReturnStatement");
   SetStatementPosition(stmt);
   Expression* expr = stmt->expression();
   // Complete the statement based on the type of the subexpression.
   if (expr->AsLiteral() != NULL) {
     __ mov(eax, expr->AsLiteral()->handle());
   } else {
     Visit(expr);
-    ASSERT(expr->location().is_temporary());
-    __ pop(eax);
+    Move(eax, expr->location());
   }
 
   if (FLAG_trace) {
     __ push(eax);
     __ CallRuntime(Runtime::kTraceExit, 1);
   }
   __ RecordJSReturn();
 
   // Do not use the leave instruction here because it is too short to
   // patch with the code required by the debugger.
   __ mov(esp, ebp);
   __ pop(ebp);
   __ ret((function_->scope()->num_parameters() + 1) * kPointerSize);
 }
 
 
 void FastCodeGenerator::VisitFunctionLiteral(FunctionLiteral* expr) {
   Comment cmnt(masm_, "[ FunctionLiteral");
 
   // Build the function boilerplate and instantiate it.
   Handle<JSFunction> boilerplate = BuildBoilerplate(expr);
   if (HasStackOverflow()) return;
 
   ASSERT(boilerplate->IsBoilerplate());
 
   // Create a new closure.
   __ push(esi);
   __ push(Immediate(boilerplate));
   __ CallRuntime(Runtime::kNewClosure, 2);
-
-  if (expr->location().is_temporary()) {
-    __ push(eax);
-  } else {
-    ASSERT(expr->location().is_nowhere());
-  }
+  Move(expr->location(), eax);
 }
 
 
 void FastCodeGenerator::VisitVariableProxy(VariableProxy* expr) {
   Comment cmnt(masm_, "[ VariableProxy");
   Expression* rewrite = expr->var()->rewrite();
   if (rewrite == NULL) {
     Comment cmnt(masm_, "Global variable");
     // Use inline caching. Variable name is passed in ecx and the global
     // object on the stack.
     __ push(CodeGenerator::GlobalObject());
     __ mov(ecx, expr->name());
     Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Initialize));
     __ call(ic, RelocInfo::CODE_TARGET_CONTEXT);
 
     // A test eax instruction following the call is used by the IC to
     // indicate that the inobject property case was inlined.  Ensure there
     // is no test eax instruction here.  Remember that the assembler may
     // choose to do peephole optimization (eg, push/pop elimination).
-    if (expr->location().is_temporary()) {
-      // Replace the global object with the result.
-      __ mov(Operand(esp, 0), eax);
-    } else {
-      ASSERT(expr->location().is_nowhere());
-      __ add(Operand(esp), Immediate(kPointerSize));
+    switch (expr->location().type()) {
+      case Location::NOWHERE:
+        __ add(Operand(esp), Immediate(kPointerSize));
+        break;
+      case Location::TEMP:
+        // Replace the global object with the result.
+        __ mov(Operand(esp, 0), eax);
+        break;
     }
 
   } else {
     Comment cmnt(masm_, "Stack slot");
-    Slot* slot = rewrite->AsSlot();
-    ASSERT(slot != NULL);
-    if (expr->location().is_temporary()) {
-      __ push(Operand(ebp, SlotOffset(slot)));
-    } else {
-      ASSERT(expr->location().is_nowhere());
-    }
-  }
-}
-
-
-void FastCodeGenerator::VisitLiteral(Literal* expr) {
-  if (expr->location().is_temporary()) {
-    __ push(Immediate(expr->handle()));
-  } else {
-    ASSERT(expr->location().is_nowhere());
+    Move(expr->location(), rewrite->AsSlot());
   }
 }
 
 
 void FastCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
   Comment cmnt(masm_, "[ ObjectLiteral");
   Label exists;
   // Registers will be used as follows:
   // edi = JS function.
   // ebx = literals array.
@@ skipping 40 matching lines @@
     if (!result_saved) {
       __ push(eax);  // Save result on the stack
       result_saved = true;
     }
     switch (property->kind()) {
       case ObjectLiteral::Property::MATERIALIZED_LITERAL:  // fall through
         ASSERT(!CompileTimeValue::IsCompileTimeValue(value));
       case ObjectLiteral::Property::COMPUTED:
         if (key->handle()->IsSymbol()) {
           Visit(value);
-          ASSERT(value->location().is_temporary());
-          __ pop(eax);
+          Move(eax, value->location());
           __ mov(ecx, Immediate(key->handle()));
           Handle<Code> ic(Builtins::builtin(Builtins::StoreIC_Initialize));
           __ call(ic, RelocInfo::CODE_TARGET);
           // StoreIC leaves the receiver on the stack.
           break;
         }
         // fall through
       case ObjectLiteral::Property::PROTOTYPE:
         __ push(eax);
         Visit(key);
-        ASSERT(key->location().is_temporary());
+        ASSERT(value->location().is_temporary());
         Visit(value);
         ASSERT(value->location().is_temporary());
         __ CallRuntime(Runtime::kSetProperty, 3);
         __ mov(eax, Operand(esp, 0));  // Restore result into eax.
         break;
       case ObjectLiteral::Property::SETTER:  // fall through
       case ObjectLiteral::Property::GETTER:
         __ push(eax);
         Visit(key);
         ASSERT(key->location().is_temporary());
         __ push(Immediate(property->kind() == ObjectLiteral::Property::SETTER ?
                           Smi::FromInt(1) :
                           Smi::FromInt(0)));
         Visit(value);
         ASSERT(value->location().is_temporary());
         __ CallRuntime(Runtime::kDefineAccessor, 4);
         __ mov(eax, Operand(esp, 0));  // Restore result into eax.
         break;
       default: UNREACHABLE();
     }
   }
-  if (expr->location().is_nowhere() && result_saved) {
-    __ add(Operand(esp), Immediate(kPointerSize));
-  } else if (expr->location().is_temporary() && !result_saved) {
-    __ push(eax);
+  switch (expr->location().type()) {
+    case Location::NOWHERE:
+      if (result_saved) __ add(Operand(esp), Immediate(kPointerSize));
+      break;
+    case Location::TEMP:
+      if (!result_saved) __ push(eax);
+      break;
   }
 }
 
 
 void FastCodeGenerator::VisitRegExpLiteral(RegExpLiteral* expr) {
   Comment cmnt(masm_, "[ RegExp Literal");
   Label done;
   // Registers will be used as follows:
   // edi = JS function.
   // ebx = literals array.
   // eax = regexp literal.
   __ mov(edi, Operand(ebp, JavaScriptFrameConstants::kFunctionOffset));
   __ mov(ebx, FieldOperand(edi, JSFunction::kLiteralsOffset));
   int literal_offset =
     FixedArray::kHeaderSize + expr->literal_index() * kPointerSize;
   __ mov(eax, FieldOperand(ebx, literal_offset));
   __ cmp(eax, Factory::undefined_value());
   __ j(not_equal, &done);
   // Create regexp literal using runtime function
   // Result will be in eax.
   __ push(ebx);
   __ push(Immediate(Smi::FromInt(expr->literal_index())));
   __ push(Immediate(expr->pattern()));
   __ push(Immediate(expr->flags()));
   __ CallRuntime(Runtime::kMaterializeRegExpLiteral, 4);
   // Label done:
   __ bind(&done);
-  if (expr->location().is_temporary()) {
-    __ push(eax);
-  } else {
-    ASSERT(expr->location().is_nowhere());
-  }
+  Move(expr->location(), eax);
 }
 
 
 void FastCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
   Comment cmnt(masm_, "[ ArrayLiteral");
   Label make_clone;
 
   // Fetch the function's literals array.
   __ mov(ebx, Operand(ebp, JavaScriptFrameConstants::kFunctionOffset));
   __ mov(ebx, FieldOperand(ebx, JSFunction::kLiteralsOffset));
@@ skipping 44 matching lines @@
     __ pop(eax);  // Subexpression value.
     __ mov(ebx, Operand(esp, 0));  // Copy of array literal.
     __ mov(ebx, FieldOperand(ebx, JSObject::kElementsOffset));
     int offset = FixedArray::kHeaderSize + (i * kPointerSize);
     __ mov(FieldOperand(ebx, offset), eax);
 
     // Update the write barrier for the array store.
     __ RecordWrite(ebx, offset, eax, ecx);
   }
 
-  Location destination = expr->location();
-  if (destination.is_nowhere() && result_saved) {
-    __ add(Operand(esp), Immediate(kPointerSize));
-  } else if (destination.is_temporary() && !result_saved) {
-    __ push(eax);
+  switch (expr->location().type()) {
+    case Location::NOWHERE:
+      if (result_saved) __ add(Operand(esp), Immediate(kPointerSize));
+      break;
+    case Location::TEMP:
+      if (!result_saved) __ push(eax);
+      break;
   }
 }
 
 
 void FastCodeGenerator::VisitAssignment(Assignment* expr) {
   Comment cmnt(masm_, "[ Assignment");
   ASSERT(expr->op() == Token::ASSIGN || expr->op() == Token::INIT_VAR);
 
   // Left-hand side can only be a global or a (parameter or local) slot.
   Variable* var = expr->target()->AsVariableProxy()->AsVariable();
   ASSERT(var != NULL);
   ASSERT(var->is_global() || var->slot() != NULL);
 
   Expression* rhs = expr->value();
-  Location destination = expr->location();
   if (var->is_global()) {
     // Assignment to a global variable, use inline caching.  Right-hand-side
     // value is passed in eax, variable name in ecx, and the global object
     // on the stack.
 
     // Code for the right-hand-side expression depends on its type.
     if (rhs->AsLiteral() != NULL) {
       __ mov(eax, rhs->AsLiteral()->handle());
     } else {
       ASSERT(rhs->location().is_temporary());
       Visit(rhs);
       __ pop(eax);
     }
     __ mov(ecx, var->name());
     __ push(CodeGenerator::GlobalObject());
     Handle<Code> ic(Builtins::builtin(Builtins::StoreIC_Initialize));
     __ call(ic, RelocInfo::CODE_TARGET);
     // Overwrite the global object on the stack with the result if needed.
-    if (destination.is_temporary()) {
-      __ mov(Operand(esp, 0), eax);
-    } else {
-      ASSERT(destination.is_nowhere());
-      __ add(Operand(esp), Immediate(kPointerSize));
+    switch (expr->location().type()) {
+      case Location::NOWHERE:
+        __ add(Operand(esp), Immediate(kPointerSize));
+        break;
+      case Location::TEMP:
+        __ mov(Operand(esp, 0), eax);
+        break;
     }
   } else {
     // Local or parameter assignment.
 
     // Code for the right-hand side expression depends on its type.
     if (rhs->AsLiteral() != NULL) {
       // Two cases: 'temp <- (var = constant)', or 'var = constant' with a
       // discarded result.  Always perform the assignment.
       __ mov(eax, rhs->AsLiteral()->handle());
       __ mov(Operand(ebp, SlotOffset(var->slot())), eax);
-      if (destination.is_temporary()) {
-        // Case 'temp <- (var = constant)'.  Save result.
-        __ push(eax);
-      }
+      Move(expr->location(), eax);
     } else {
       ASSERT(rhs->location().is_temporary());
       Visit(rhs);
-      if (destination.is_temporary()) {
-        // Case 'temp1 <- (var = temp0)'.  Preserve right-hand-side
-        // temporary on the stack.
-        __ mov(eax, Operand(esp, 0));
-        __ mov(Operand(ebp, SlotOffset(var->slot())), eax);
-      } else {
-        ASSERT(destination.is_nowhere());
-        // Case 'var = temp'.  Discard right-hand-side temporary.
-        __ pop(Operand(ebp, SlotOffset(var->slot())));
+      switch (expr->location().type()) {
+        case Location::NOWHERE:
+          // Case 'var = temp'.  Discard right-hand-side temporary.
+          Move(var->slot(), rhs->location());
+          break;
+        case Location::TEMP:
+          // Case 'temp1 <- (var = temp0)'.  Preserve right-hand-side
+          // temporary on the stack.
+          __ mov(eax, Operand(esp, 0));
+          __ mov(Operand(ebp, SlotOffset(var->slot())), eax);
+          break;
       }
     }
   }
 }
 
 
 void FastCodeGenerator::VisitCall(Call* expr) {
   Expression* fun = expr->expression();
   ZoneList<Expression*>* args = expr->arguments();
   Variable* var = fun->AsVariableProxy()->AsVariable();
@@ skipping 10 matching lines @@
   }
   // Record source position for debugger
   SetSourcePosition(expr->position());
   // Call the IC initialization code.
   Handle<Code> ic = CodeGenerator::ComputeCallInitialize(arg_count,
                                                          NOT_IN_LOOP);
   __ call(ic, RelocInfo::CODE_TARGET_CONTEXT);
   // Restore context register.
   __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
   // Discard the function left on TOS.
-  if (expr->location().is_temporary()) {
-    __ mov(Operand(esp, 0), eax);
-  } else {
-    ASSERT(expr->location().is_nowhere());
-    __ add(Operand(esp), Immediate(kPointerSize));
+  switch (expr->location().type()) {
+    case Location::NOWHERE:
+      __ add(Operand(esp), Immediate(kPointerSize));
+      break;
+    case Location::TEMP:
+      __ mov(Operand(esp, 0), eax);
+      break;
   }
 }
 
 
 void FastCodeGenerator::VisitCallRuntime(CallRuntime* expr) {
   Comment cmnt(masm_, "[ CallRuntime");
   ZoneList<Expression*>* args = expr->arguments();
   Runtime::Function* function = expr->function();
 
   ASSERT(function != NULL);
 
   // Push the arguments ("left-to-right").
   int arg_count = args->length();
   for (int i = 0; i < arg_count; i++) {
     Visit(args->at(i));
     ASSERT(args->at(i)->location().is_temporary());
   }
 
   __ CallRuntime(function, arg_count);
-  if (expr->location().is_temporary()) {
-    __ push(eax);
-  } else {
-    ASSERT(expr->location().is_nowhere());
-  }
+  Move(expr->location(), eax);
 }
 
 
 void FastCodeGenerator::VisitBinaryOperation(BinaryOperation* expr) {
   // Compile a short-circuited boolean or operation in a non-test
   // context.
   ASSERT(expr->op() == Token::OR);
   // Compile (e0 || e1) as if it were
   // (let (temp = e0) temp ? temp : e1).
 
   Label eval_right, done;
   Location destination = expr->location();
   Expression* left = expr->left();
   Expression* right = expr->right();
 
   // Use the shared ToBoolean stub to find the boolean value of the
   // left-hand subexpression.  Load the value into eax to perform some
   // inlined checks assumed by the stub.
 
   // Compile the left-hand value into eax.  Put it on the stack if we may
   // need it as the value of the whole expression.
   if (left->AsLiteral() != NULL) {
     __ mov(eax, left->AsLiteral()->handle());
     if (destination.is_temporary()) __ push(eax);
   } else {
     Visit(left);
     ASSERT(left->location().is_temporary());
-    if (destination.is_temporary()) {
-      // Copy the left-hand value into eax because we may need it as the
-      // final result.
-      __ mov(eax, Operand(esp, 0));
-    } else {
-      // Pop the left-hand value into eax because we will not need it as the
-      // final result.
-      __ pop(eax);
+    switch (destination.type()) {
+      case Location::NOWHERE:
+        // Pop the left-hand value into eax because we will not need it as the
+        // final result.
+        __ pop(eax);
+        break;
+      case Location::TEMP:
+        // Copy the left-hand value into eax because we may need it as the
+        // final result.
+        __ mov(eax, Operand(esp, 0));
+        break;
     }
   }
   // The left-hand value is in eax.  It is also on the stack iff the
   // destination location is temporary.
 
   // Perform fast checks assumed by the stub.
   __ cmp(eax, Factory::undefined_value());  // The undefined value is false.
   __ j(equal, &eval_right);
   __ cmp(eax, Factory::true_value());  // True is true.
   __ j(equal, &done);
@@ skipping 12 matching lines @@
   __ test(eax, Operand(eax));  // The stub returns nonzero for true.
   __ j(not_zero, &done);
 
   __ bind(&eval_right);
   // Discard the left-hand value if present on the stack.
   if (destination.is_temporary()) {
     __ add(Operand(esp), Immediate(kPointerSize));
   }
   // Save or discard the right-hand value as needed.
   if (right->AsLiteral() != NULL) {
-    if (destination.is_temporary()) {
-      __ push(Immediate(right->AsLiteral()->handle()));
-    } else {
-      ASSERT(destination.is_nowhere());
-    }
+    Move(destination, right->AsLiteral());
   } else {
     Visit(right);
-    ASSERT(right->location().is_temporary());
-    if (destination.is_nowhere()) {
-      __ add(Operand(esp), Immediate(kPointerSize));
-    } else {
-      ASSERT(destination.is_temporary());
-    }
+    Move(destination, right->location());
   }
 
   __ bind(&done);
 }
 
 
 } }  // namespace v8::internal