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

src/arm/fast-codegen-arm.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 102 matching lines @@
     __ RecordJSReturn();
     __ mov(sp, fp);
     __ ldm(ia_w, sp, fp.bit() | lr.bit());
     int num_parameters = function_->scope()->num_parameters();
     __ add(sp, sp, Operand((num_parameters + 1) * kPointerSize));
     __ Jump(lr);
   }
 }
 
 
+void FastCodeGenerator::Move(Location destination, Slot* source) {
+  switch (destination.type()) {
+    case Location::NOWHERE:
+      break;
+    case Location::TEMP:
+      __ ldr(ip, MemOperand(fp, SlotOffset(source)));
+      __ push(ip);
+      break;
+  }
+}
+
+
+void FastCodeGenerator::Move(Location destination, Literal* expr) {
+  switch (destination.type()) {
+    case Location::NOWHERE:
+      break;
+    case Location::TEMP:
+      __ mov(ip, Operand(expr->handle()));
+      __ push(ip);
+      break;
+  }
+}
+
+
+void FastCodeGenerator::Move(Slot* destination, Location source) {
+  switch (source.type()) {
+    case Location::NOWHERE:
+      UNREACHABLE();
+    case Location::TEMP:
+      __ pop(ip);
+      __ str(ip, MemOperand(fp, SlotOffset(destination)));
+      break;
+  }
+}
+
+
 void FastCodeGenerator::DeclareGlobals(Handle<FixedArray> pairs) {
   // Call the runtime to declare the globals.
   // The context is the first argument.
   __ mov(r1, Operand(pairs));
   __ mov(r0, Operand(Smi::FromInt(is_eval_ ? 1 : 0)));
   __ stm(db_w, sp, cp.bit() | r1.bit() | r0.bit());
   __ 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(r0, Operand(expr->AsLiteral()->handle()));
   } else {
     Visit(expr);
     ASSERT(expr->location().is_temporary());
@@ skipping 20 matching lines @@
   // Build the function boilerplate and instantiate it.
   Handle<JSFunction> boilerplate = BuildBoilerplate(expr);
   if (HasStackOverflow()) return;
 
   ASSERT(boilerplate->IsBoilerplate());
 
   // Create a new closure.
   __ mov(r0, Operand(boilerplate));
   __ stm(db_w, sp, cp.bit() | r0.bit());
   __ CallRuntime(Runtime::kNewClosure, 2);
-
-  if (expr->location().is_temporary()) {
-    __ push(r0);
-  } else {
-    ASSERT(expr->location().is_nowhere());
-  }
+  Move(expr->location(), r0);
 }
 
 
 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 r2 and the global
     // object on the stack.
     __ ldr(ip, CodeGenerator::GlobalObject());
     __ push(ip);
     __ mov(r2, Operand(expr->name()));
     Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Initialize));
     __ Call(ic, RelocInfo::CODE_TARGET_CONTEXT);
-    if (expr->location().is_temporary()) {
-      // Replace the global object with the result.
-      __ str(r0, MemOperand(sp));
-    } else {
-      ASSERT(expr->location().is_nowhere());
-      __ pop();
+    switch (expr->location().type()) {
+      case Location::NOWHERE:
+        __ pop();
+        break;
+      case Location::TEMP:
+        // Replace the global object with the result.
+        __ str(r0, MemOperand(sp));
+        break;
     }
 
   } else {
     Comment cmnt(masm_, "Stack slot");
-    Slot* slot = rewrite->AsSlot();
-    ASSERT(slot != NULL);
-    if (expr->location().is_temporary()) {
-      __ ldr(ip, MemOperand(fp, SlotOffset(slot)));
-      __ push(ip);
-    } else {
-      ASSERT(expr->location().is_nowhere());
-    }
-  }
-}
-
-
-void FastCodeGenerator::VisitLiteral(Literal* expr) {
-  if (expr->location().is_temporary()) {
-    __ mov(ip, Operand(expr->AsLiteral()->handle()));
-    __ push(ip);
-  } else {
-    ASSERT(expr->location().is_nowhere());
+    Move(expr->location(), rewrite->AsSlot());
   }
 }
 
 
 void FastCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
   Comment cmnt(masm_, "[ ObjectLiteral");
   Label boilerplate_exists;
   __ ldr(r2, MemOperand(fp,  JavaScriptFrameConstants::kFunctionOffset));
   // r2 = literal array (0).
   __ ldr(r2, FieldMemOperand(r2, JSFunction::kLiteralsOffset));
@@ skipping 61 matching lines @@
                            Smi::FromInt(0)));
         __ push(r1);
         Visit(value);
         ASSERT(value->location().is_temporary());
         __ CallRuntime(Runtime::kDefineAccessor, 4);
         __ ldr(r0, MemOperand(sp));  // Restore result into r0
         break;
       default: UNREACHABLE();
     }
   }
-  if (expr->location().is_nowhere() && result_saved) {
-    __ pop();
-  } else if (expr->location().is_temporary() && !result_saved) {
-    ASSERT(expr->location().is_temporary());
-    __ push(r0);
+  switch (expr->location().type()) {
+    case Location::NOWHERE:
+      if (result_saved) __ pop();
+      break;
+    case Location::TEMP:
+      if (!result_saved) __ push(r0);
+      break;
   }
 }
 
 
 void FastCodeGenerator::VisitRegExpLiteral(RegExpLiteral* expr) {
   Comment cmnt(masm_, "[ RegExp Literal");
   Label done;
   // Registers will be used as follows:
   // r4 = JS function, literals array
   // r3 = literal index
   // r2 = RegExp pattern
   // r1 = RegExp flags
   // r0 = temp + return value (RegExp literal)
   __ ldr(r0, MemOperand(fp,  JavaScriptFrameConstants::kFunctionOffset));
   __ ldr(r4,  FieldMemOperand(r0, JSFunction::kLiteralsOffset));
   int literal_offset =
     FixedArray::kHeaderSize + expr->literal_index() * kPointerSize;
   __ ldr(r0, FieldMemOperand(r4, literal_offset));
   __ LoadRoot(ip, Heap::kUndefinedValueRootIndex);
   __ cmp(r0, ip);
   __ b(ne, &done);
   __ mov(r3, Operand(Smi::FromInt(expr->literal_index())));
   __ mov(r2, Operand(expr->pattern()));
   __ mov(r1, Operand(expr->flags()));
   __ stm(db_w, sp, r4.bit() | r3.bit() | r2.bit() | r1.bit());
   __ CallRuntime(Runtime::kMaterializeRegExpLiteral, 4);
   __ bind(&done);
-  if (expr->location().is_temporary()) {
-    __ push(r0);
-  } else {
-    ASSERT(expr->location().is_nowhere());
-  }
+  Move(expr->location(), r0);
 }
 
 
 void FastCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
   Comment cmnt(masm_, "[ ArrayLiteral");
   Label make_clone;
 
   // Fetch the function's literals array.
   __ ldr(r3, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
   __ ldr(r3, FieldMemOperand(r3, JSFunction::kLiteralsOffset));
@@ skipping 47 matching lines @@
     __ ldr(r1, FieldMemOperand(r1, JSObject::kElementsOffset));
     int offset = FixedArray::kHeaderSize + (i * kPointerSize);
     __ str(r0, FieldMemOperand(r1, offset));
 
     // Update the write barrier for the array store with r0 as the scratch
     // register.
     __ mov(r2, Operand(offset));
     __ RecordWrite(r1, r2, r0);
   }
 
-  Location destination = expr->location();
-  if (destination.is_nowhere() && result_saved) {
-    __ pop();
-  } else if (destination.is_temporary() && !result_saved) {
-    __ push(r0);
+  switch (expr->location().type()) {
+    case Location::NOWHERE:
+      if (result_saved) __ pop();
+      break;
+    case Location::TEMP:
+      if (!result_saved) __ push(r0);
+      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();
@@ skipping 14 matching lines @@
       ASSERT(rhs->location().is_temporary());
       Visit(rhs);
       __ pop(r0);
     }
     __ mov(r2, Operand(var->name()));
     __ ldr(ip, CodeGenerator::GlobalObject());
     __ push(ip);
     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()) {
-      __ str(r0, MemOperand(sp));
-    } else {
-      ASSERT(destination.is_nowhere());
-      __ pop();
+    switch (expr->location().type()) {
+      case Location::NOWHERE:
+        __ pop();
+        break;
+      case Location::TEMP:
+        __ str(r0, MemOperand(sp));
+        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(ip, Operand(rhs->AsLiteral()->handle()));
       __ str(ip, MemOperand(fp, SlotOffset(var->slot())));
-      if (destination.is_temporary()) {
-        // Case 'temp <- (var = constant)'.  Save result.
-        __ push(ip);
-      }
+      Move(expr->location(), ip);
     } else {
       ASSERT(rhs->location().is_temporary());
       Visit(rhs);
-      if (destination.is_temporary()) {
-        // Case 'temp1 <- (var = temp0)'.  Preserve right-hand-side
-        // temporary on the stack.
-        __ ldr(ip, MemOperand(sp));
-      } else {
-        ASSERT(destination.is_nowhere());
-        // Case 'var = temp'.  Discard right-hand-side temporary.
-        __ pop(ip);
+      // Load right-hand side into ip.
+      switch (expr->location().type()) {
+        case Location::NOWHERE:
+          // Case 'var = temp'.  Discard right-hand-side temporary.
+          __ pop(ip);
+          break;
+        case Location::TEMP:
+          // Case 'temp1 <- (var = temp0)'.  Preserve right-hand-side
+          // temporary on the stack.
+          __ ldr(ip, MemOperand(sp));
+          break;
       }
+      // Do the slot assignment.
       __ str(ip, MemOperand(fp, SlotOffset(var->slot())));
     }
   }
 }
 
 
 void FastCodeGenerator::VisitCall(Call* expr) {
   Comment cmnt(masm_, "[ Call");
   Expression* fun = expr->expression();
   ZoneList<Expression*>* args = expr->arguments();
@@ skipping 11 matching lines @@
     ASSERT(args->at(i)->location().is_temporary());
   }
   // 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.
   __ ldr(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
-  if (expr->location().is_temporary()) {
-    __ str(r0, MemOperand(sp));
-  } else {
-    ASSERT(expr->location().is_nowhere());
-    __ pop();
+  switch (expr->location().type()) {
+    case Location::NOWHERE:
+      __ pop();
+      break;
+    case Location::TEMP:
+      __ str(r0, MemOperand(sp));
+      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(r0);
-  } else {
-    ASSERT(expr->location().is_nowhere());
-  }
+  Move(expr->location(), r0);
 }
 
 
 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).
 
@@ skipping 21 matching lines @@
   // stack iff the destination location is temporary.
   __ CallRuntime(Runtime::kToBool, 1);
   __ LoadRoot(ip, Heap::kTrueValueRootIndex);
   __ cmp(r0, ip);
   __ b(eq, &done);
 
   // Discard the left-hand value if present on the stack.
   if (destination.is_temporary()) __ pop();
   // Save or discard the right-hand value as needed.
   if (right->AsLiteral() != NULL) {
-    if (destination.is_temporary()) {
-      __ mov(ip, Operand(right->AsLiteral()->handle()));
-      __ push(ip);
-    } else {
-      ASSERT(destination.is_nowhere());
-    }
+    Move(destination, right->AsLiteral());
   } else {
     Visit(right);
-    ASSERT(right->location().is_temporary());
-    if (destination.is_nowhere()) {
-      __ pop();
-    } else {
-      ASSERT(destination.is_temporary());
-    }
+    Move(destination, right->location());
   }
 
   __ bind(&done);
 }
 
 } }  // namespace v8::internal