NOT FOR COMMITTING: Add fast side-effect free floating point expressions.

src/ia32/safe-codegen-ia32.h

Index: src/ia32/safe-codegen-ia32.h
===================================================================
--- src/ia32/safe-codegen-ia32.h	(revision 0)
+++ src/ia32/safe-codegen-ia32.h	(revision 0)
@@ -0,0 +1,129 @@
+// Copyright 2010 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
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_SAFE_CODEGEN_IA32_H_
+#define V8_SAFE_CODEGEN_IA32_H_
+
+#include "v8.h"
+
+namespace v8 {
+namespace internal {
+
+class SafeSyntaxChecker: public AstVisitor {
+ public:
+  SafeSyntaxChecker()
+      : has_supported_syntax_(true),
+        xmm_stack_height_(0),
+        num_operations_(0),
+        has_constant_float_(false) {}
+  bool Check(Expression* expression) {
+    Visit(expression);
+    CHECK(!has_supported_syntax() || xmm_stack_height_ == 1);
+    return has_supported_syntax() &&
+        num_operations_ > 1;
+  }
+
+ private:
+  bool has_supported_syntax() { return has_supported_syntax_; }
+  static const int MAX_XMM_STACK_HEIGHT = 8;
+  // AST node visit functions.
+#define DECLARE_VISIT(type) virtual void Visit##type(type* node);
+  AST_NODE_LIST(DECLARE_VISIT)
+#undef DECLARE_VISIT
+
+  bool has_supported_syntax_;
+  int xmm_stack_height_;
+  int num_operations_;
+  bool has_constant_float_;
+  DISALLOW_COPY_AND_ASSIGN(SafeSyntaxChecker);
+};
+
+
+class SafeGenerator: public AstVisitor {
+ public:
+
+  SafeGenerator(MacroAssembler* masm,
+                JumpTarget* unsafe_target,
+                CodeGenerator* cgen,
+                Result* scratch,
+                Result* final_result)
+      : masm_(masm),
+        unsafe_target_(unsafe_target),
+        cgen_(cgen),
+        scratch_(scratch),
+        final_result_(final_result),
+        xmm_stack_height_(0) {}
+
+
+  Result Generate(Expression* expr);
+ private:
+  MacroAssembler* masm() { return masm_; }
+
+  // AST node visit functions.
+#define DECLARE_VISIT(type) virtual void Visit##type(type* node);
+  AST_NODE_LIST(DECLARE_VISIT)
+#undef DECLARE_VISIT
+
+  static const int kMinUnspilledXMMRegisters = 4;
+  static const int kNumXMMRegisters = 8;
+
+  MacroAssembler* masm_;
+  JumpTarget* unsafe_target_;
+  CodeGenerator* cgen_;
+  Result* scratch_;
+  Result* final_result_;
+
+  // Implement a stack from the XMM registers (keeping the top up-to-8 elements
+  // of the stack in registers).
+  // Next xmm register to use.
+  int xmm_stack_height_;
+  // Operations on the XMM "stack".
+  void PushXMM(Handle<HeapNumber> value);
+  void PushXMM(Handle<Smi> literal);
+  void PushXMM(Slot* variable);
+
+  void StoreXMM(Register heapNumber);
+  // Utility functions.
+  void FreeStackTop() {
+    ASSERT(xmm_stack_height_ > 0);
+    xmm_stack_height_--;
+  }
+
+  XMMRegister AllocateStackElement() {
+    xmm_stack_height_++;
+    return XMMStackElement(0);
+  }
+
+  XMMRegister XMMStackElement(int offset_from_top);
+
+  DISALLOW_COPY_AND_ASSIGN(SafeGenerator);
+};
+
+
+} }  // namespace v8::internal
+
+#endif  // V8_SAFE_CODEGEN_IA32_H_