Land the Fan (disabled)

src/compiler/frame.h

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_COMPILER_FRAME_H_
+#define V8_COMPILER_FRAME_H_
+
+#include "src/v8.h"
+
+#include "src/data-flow.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+// Collects the spill slot requirements and the allocated general and double
+// registers for a compiled function. Frames are usually populated by the
+// register allocator and are used by Linkage to generate code for the prologue
+// and epilogue to compiled code.
+class Frame {
+ public:
+  Frame()
+    : register_save_area_size_(0),
+      spill_slot_count_(0),
+      double_spill_slot_count_(0),
+      allocated_registers_(NULL),
+      allocated_double_registers_(NULL) { }
+
+  inline int GetSpillSlotCount() { return spill_slot_count_; }
+  inline int GetDoubleSpillSlotCount() { return double_spill_slot_count_; }
+
+  void SetAllocatedRegisters(BitVector* regs) {
+    ASSERT(allocated_registers_ == NULL);
+    allocated_registers_ = regs;
+  }
+
+  void SetAllocatedDoubleRegisters(BitVector* regs) {
+    ASSERT(allocated_double_registers_ == NULL);
+    allocated_double_registers_ = regs;
+  }
+
+  bool DidAllocateDoubleRegisters() {
+    return !allocated_double_registers_->IsEmpty();
+  }
+
+  void SetRegisterSaveAreaSize(int size) {
+    ASSERT(IsAligned(size, kPointerSize));
+    register_save_area_size_ = size;
+  }
+
+  int GetRegisterSaveAreaSize() {
+    return register_save_area_size_;
+  }
+
+  int AllocateSpillSlot(bool is_double) {
+    // If 32-bit, skip one if the new slot is a double.
+    if (is_double) {
+      if (kDoubleSize > kPointerSize) {
+        ASSERT(kDoubleSize == kPointerSize * 2);
+        spill_slot_count_++;
+        spill_slot_count_ |= 1;
+      }
+      double_spill_slot_count_++;
+    }
+    return spill_slot_count_++;
+  }
+
+ private:
+  int register_save_area_size_;
+  int spill_slot_count_;
+  int double_spill_slot_count_;
+  BitVector* allocated_registers_;
+  BitVector* allocated_double_registers_;
+};
+
+
+// Represents an offset from either the stack pointer or frame pointer.
+class FrameOffset {
+ public:
+  inline bool from_stack_pointer() { return (offset_ & 1) == kFromSp; }
+  inline bool from_frame_pointer() { return (offset_ & 1) == kFromFp; }
+  inline int offset() { return offset_ & ~1; }
+
+  inline static FrameOffset FromStackPointer(int offset) {
+    ASSERT((offset & 1) == 0);
+    return FrameOffset(offset | kFromSp);
+  }
+
+  inline static FrameOffset FromFramePointer(int offset) {
+    ASSERT((offset & 1) == 0);
+    return FrameOffset(offset | kFromFp);
+  }
+
+ private:
+  explicit FrameOffset(int offset) : offset_(offset) { }
+
+  int offset_;  // Encodes SP or FP in the low order bit.
+
+  static const int kFromSp = 1;
+  static const int kFromFp = 0;
+};
+
+} } }  // namespace v8::internal::compiler
+
+#endif  // V8_COMPILER_FRAME_H_