Move IC code into a subdir and move ic-compilation related code from stub-cache into ic-compiler

src/ic/stub-cache.h

+// Copyright 2012 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_STUB_CACHE_H_
+#define V8_STUB_CACHE_H_
+
+#include "src/macro-assembler.h"
+
+namespace v8 {
+namespace internal {
+
+
+// The stub cache is used for megamorphic property accesses.
+// It maps (map, name, type) to property access handlers. The cache does not
+// need explicit invalidation when a prototype chain is modified, since the
+// handlers verify the chain.
+
+
+class SCTableReference {
+ public:
+  Address address() const { return address_; }
+
+ private:
+  explicit SCTableReference(Address address) : address_(address) {}
+
+  Address address_;
+
+  friend class StubCache;
+};
+
+
+class StubCache {
+ public:
+  struct Entry {
+    Name* key;
+    Code* value;
+    Map* map;
+  };
+
+  void Initialize();
+  // Access cache for entry hash(name, map).
+  Code* Set(Name* name, Map* map, Code* code);
+  Code* Get(Name* name, Map* map, Code::Flags flags);
+  // Clear the lookup table (@ mark compact collection).
+  void Clear();
+  // Collect all maps that match the name and flags.
+  void CollectMatchingMaps(SmallMapList* types, Handle<Name> name,
+                           Code::Flags flags, Handle<Context> native_context,
+                           Zone* zone);
+  // Generate code for probing the stub cache table.
+  // Arguments extra, extra2 and extra3 may be used to pass additional scratch
+  // registers. Set to no_reg if not needed.
+  void GenerateProbe(MacroAssembler* masm, Code::Flags flags, Register receiver,
+                     Register name, Register scratch, Register extra,
+                     Register extra2 = no_reg, Register extra3 = no_reg);
+
+  enum Table { kPrimary, kSecondary };
+
+  SCTableReference key_reference(StubCache::Table table) {
+    return SCTableReference(
+        reinterpret_cast<Address>(&first_entry(table)->key));
+  }
+
+  SCTableReference map_reference(StubCache::Table table) {
+    return SCTableReference(
+        reinterpret_cast<Address>(&first_entry(table)->map));
+  }
+
+  SCTableReference value_reference(StubCache::Table table) {
+    return SCTableReference(
+        reinterpret_cast<Address>(&first_entry(table)->value));
+  }
+
+  StubCache::Entry* first_entry(StubCache::Table table) {
+    switch (table) {
+      case StubCache::kPrimary:
+        return StubCache::primary_;
+      case StubCache::kSecondary:
+        return StubCache::secondary_;
+    }
+    UNREACHABLE();
+    return NULL;
+  }
+
+  Isolate* isolate() { return isolate_; }
+
+  // Setting the entry size such that the index is shifted by Name::kHashShift
+  // is convenient; shifting down the length field (to extract the hash code)
+  // automatically discards the hash bit field.
+  static const int kCacheIndexShift = Name::kHashShift;
+
+ private:
+  explicit StubCache(Isolate* isolate);
+
+  // The stub cache has a primary and secondary level.  The two levels have
+  // different hashing algorithms in order to avoid simultaneous collisions
+  // in both caches.  Unlike a probing strategy (quadratic or otherwise) the
+  // update strategy on updates is fairly clear and simple:  Any existing entry
+  // in the primary cache is moved to the secondary cache, and secondary cache
+  // entries are overwritten.
+
+  // Hash algorithm for the primary table.  This algorithm is replicated in
+  // assembler for every architecture.  Returns an index into the table that
+  // is scaled by 1 << kCacheIndexShift.
+  static int PrimaryOffset(Name* name, Code::Flags flags, Map* map) {
+    STATIC_ASSERT(kCacheIndexShift == Name::kHashShift);
+    // Compute the hash of the name (use entire hash field).
+    DCHECK(name->HasHashCode());
+    uint32_t field = name->hash_field();
+    // Using only the low bits in 64-bit mode is unlikely to increase the
+    // risk of collision even if the heap is spread over an area larger than
+    // 4Gb (and not at all if it isn't).
+    uint32_t map_low32bits =
+        static_cast<uint32_t>(reinterpret_cast<uintptr_t>(map));
+    // We always set the in_loop bit to zero when generating the lookup code
+    // so do it here too so the hash codes match.
+    uint32_t iflags =
+        (static_cast<uint32_t>(flags) & ~Code::kFlagsNotUsedInLookup);
+    // Base the offset on a simple combination of name, flags, and map.
+    uint32_t key = (map_low32bits + field) ^ iflags;
+    return key & ((kPrimaryTableSize - 1) << kCacheIndexShift);
+  }
+
+  // Hash algorithm for the secondary table.  This algorithm is replicated in
+  // assembler for every architecture.  Returns an index into the table that
+  // is scaled by 1 << kCacheIndexShift.
+  static int SecondaryOffset(Name* name, Code::Flags flags, int seed) {
+    // Use the seed from the primary cache in the secondary cache.
+    uint32_t name_low32bits =
+        static_cast<uint32_t>(reinterpret_cast<uintptr_t>(name));
+    // We always set the in_loop bit to zero when generating the lookup code
+    // so do it here too so the hash codes match.
+    uint32_t iflags =
+        (static_cast<uint32_t>(flags) & ~Code::kFlagsNotUsedInLookup);
+    uint32_t key = (seed - name_low32bits) + iflags;
+    return key & ((kSecondaryTableSize - 1) << kCacheIndexShift);
+  }
+
+  // Compute the entry for a given offset in exactly the same way as
+  // we do in generated code.  We generate an hash code that already
+  // ends in Name::kHashShift 0s.  Then we multiply it so it is a multiple
+  // of sizeof(Entry).  This makes it easier to avoid making mistakes
+  // in the hashed offset computations.
+  static Entry* entry(Entry* table, int offset) {
+    const int multiplier = sizeof(*table) >> Name::kHashShift;
+    return reinterpret_cast<Entry*>(reinterpret_cast<Address>(table) +
+                                    offset * multiplier);
+  }
+
+  static const int kPrimaryTableBits = 11;
+  static const int kPrimaryTableSize = (1 << kPrimaryTableBits);
+  static const int kSecondaryTableBits = 9;
+  static const int kSecondaryTableSize = (1 << kSecondaryTableBits);
+
+  Entry primary_[kPrimaryTableSize];
+  Entry secondary_[kSecondaryTableSize];
+  Isolate* isolate_;
+
+  friend class Isolate;
+  friend class SCTableReference;
+
+  DISALLOW_COPY_AND_ASSIGN(StubCache);
+};
+}
+}  // namespace v8::internal
+
+#endif  // V8_STUB_CACHE_H_