Import Clang, at r72732.

1 files changed, 362 insertions, 0 deletions

diff --git a/include/clang/Basic/OnDiskHashTable.h b/include/clang/Basic/OnDiskHashTable.h
new file mode 100644
index 0000000..f54d670
--- /dev/null
+++ b/include/clang/Basic/OnDiskHashTable.h
@@ -0,0 +1,362 @@
+//===--- OnDiskHashTable.h - On-Disk Hash Table Implementation --*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file defines facilities for reading and writing on-disk hash
+//  tables.
+//
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_CLANG_BASIC_ON_DISK_HASH_TABLE_H
+#define LLVM_CLANG_BASIC_ON_DISK_HASH_TABLE_H
+
+#include "llvm/Support/Allocator.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/DataTypes.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/System/Host.h"
+#include <cassert>
+#include <cstdlib>
+
+namespace clang {
+
+// Bernstein hash function:
+// This is basically copy-and-paste from StringMap.  This likely won't
+// stay here, which is why I didn't both to expose this function from
+// String Map.
+inline unsigned BernsteinHash(const char* x) {  
+  unsigned int R = 0;
+  for ( ; *x != '\0' ; ++x) R = R * 33 + *x;
+  return R + (R >> 5);
+}
+
+inline unsigned BernsteinHash(const char* x, unsigned n) {
+  unsigned int R = 0;
+  for (unsigned i = 0 ; i < n ; ++i, ++x) R = R * 33 + *x;
+  return R + (R >> 5);
+}
+
+inline unsigned BernsteinHashPartial(const char* x, unsigned n, unsigned R) {
+  for (unsigned i = 0 ; i < n ; ++i, ++x) R = R * 33 + *x;
+  return R + (R >> 5);
+}
+
+namespace io {
+
+typedef uint32_t Offset;
+
+inline void Emit8(llvm::raw_ostream& Out, uint32_t V) {
+  Out << (unsigned char)(V);
+}
+
+inline void Emit16(llvm::raw_ostream& Out, uint32_t V) {
+  Out << (unsigned char)(V);
+  Out << (unsigned char)(V >>  8);
+  assert((V >> 16) == 0);
+}
+
+inline void Emit32(llvm::raw_ostream& Out, uint32_t V) {
+  Out << (unsigned char)(V);
+  Out << (unsigned char)(V >>  8);
+  Out << (unsigned char)(V >> 16);
+  Out << (unsigned char)(V >> 24);
+}
+
+inline void Emit64(llvm::raw_ostream& Out, uint64_t V) {
+  Out << (unsigned char)(V);
+  Out << (unsigned char)(V >>  8);
+  Out << (unsigned char)(V >> 16);
+  Out << (unsigned char)(V >> 24);
+  Out << (unsigned char)(V >> 32);
+  Out << (unsigned char)(V >> 40);
+  Out << (unsigned char)(V >> 48);
+  Out << (unsigned char)(V >> 56);
+}
+
+inline void Pad(llvm::raw_ostream& Out, unsigned A) {
+  Offset off = (Offset) Out.tell();
+  uint32_t n = ((uintptr_t)(off+A-1) & ~(uintptr_t)(A-1)) - off;
+  for (; n ; --n)
+    Emit8(Out, 0);
+}
+
+inline uint16_t ReadUnalignedLE16(const unsigned char *&Data) {
+  uint16_t V = ((uint16_t)Data[0]) |
+               ((uint16_t)Data[1] <<  8);
+  Data += 2;
+  return V;
+}
+
+inline uint32_t ReadUnalignedLE32(const unsigned char *&Data) {
+  uint32_t V = ((uint32_t)Data[0])  |
+               ((uint32_t)Data[1] << 8)  |
+               ((uint32_t)Data[2] << 16) |
+               ((uint32_t)Data[3] << 24);
+  Data += 4;
+  return V;
+}
+
+inline uint64_t ReadUnalignedLE64(const unsigned char *&Data) {
+  uint64_t V = ((uint64_t)Data[0])  |
+    ((uint64_t)Data[1] << 8)  |
+    ((uint64_t)Data[2] << 16) |
+    ((uint64_t)Data[3] << 24) |
+    ((uint64_t)Data[4] << 32) |
+    ((uint64_t)Data[5] << 40) |
+    ((uint64_t)Data[6] << 48) |
+    ((uint64_t)Data[7] << 56);
+  Data += 8;
+  return V;
+}
+
+inline uint32_t ReadLE32(const unsigned char *&Data) {
+  // Hosts that directly support little-endian 32-bit loads can just
+  // use them.  Big-endian hosts need a bswap.
+  uint32_t V = *((uint32_t*)Data);
+  if (llvm::sys::isBigEndianHost())
+    V = llvm::ByteSwap_32(V);
+  Data += 4;
+  return V;
+}
+
+} // end namespace io
+
+template<typename Info>
+class OnDiskChainedHashTableGenerator {
+  unsigned NumBuckets;
+  unsigned NumEntries;
+  llvm::BumpPtrAllocator BA;
+  
+  class Item {
+  public:
+    typename Info::key_type key;
+    typename Info::data_type data;
+    Item *next;
+    const uint32_t hash;
+    
+    Item(typename Info::key_type_ref k, typename Info::data_type_ref d)
+    : key(k), data(d), next(0), hash(Info::ComputeHash(k)) {}
+  };
+  
+  class Bucket { 
+  public:
+    io::Offset off;
+    Item*  head;
+    unsigned length;
+    
+    Bucket() {}
+  };
+  
+  Bucket* Buckets;
+  
+private:
+  void insert(Bucket* b, size_t size, Item* E) {
+    unsigned idx = E->hash & (size - 1);
+    Bucket& B = b[idx];
+    E->next = B.head;
+    ++B.length;
+    B.head = E;
+  }
+  
+  void resize(size_t newsize) {
+    Bucket* newBuckets = (Bucket*) std::calloc(newsize, sizeof(Bucket));
+    // Populate newBuckets with the old entries.
+    for (unsigned i = 0; i < NumBuckets; ++i)
+      for (Item* E = Buckets[i].head; E ; ) {
+        Item* N = E->next;
+        E->next = 0;
+        insert(newBuckets, newsize, E);
+        E = N;
+      }
+    
+    free(Buckets);
+    NumBuckets = newsize;
+    Buckets = newBuckets;
+  }  
+  
+public:
+  
+  void insert(typename Info::key_type_ref key,
+              typename Info::data_type_ref data) {
+
+    ++NumEntries;
+    if (4*NumEntries >= 3*NumBuckets) resize(NumBuckets*2);
+    insert(Buckets, NumBuckets, new (BA.Allocate<Item>()) Item(key, data));
+  }
+  
+  io::Offset Emit(llvm::raw_ostream &out) {
+    Info InfoObj;
+    return Emit(out, InfoObj);
+  }
+
+  io::Offset Emit(llvm::raw_ostream &out, Info &InfoObj) {
+    using namespace clang::io;
+
+    // Emit the payload of the table.
+    for (unsigned i = 0; i < NumBuckets; ++i) {
+      Bucket& B = Buckets[i];
+      if (!B.head) continue;
+      
+      // Store the offset for the data of this bucket.
+      B.off = out.tell();
+      assert(B.off && "Cannot write a bucket at offset 0. Please add padding.");
+
+      // Write out the number of items in the bucket.
+      Emit16(out, B.length);
+      
+      // Write out the entries in the bucket.
+      for (Item *I = B.head; I ; I = I->next) {
+        Emit32(out, I->hash);
+        const std::pair<unsigned, unsigned>& Len = 
+          InfoObj.EmitKeyDataLength(out, I->key, I->data);
+        InfoObj.EmitKey(out, I->key, Len.first);
+        InfoObj.EmitData(out, I->key, I->data, Len.second);
+      }
+    }
+    
+    // Emit the hashtable itself.
+    Pad(out, 4);
+    io::Offset TableOff = out.tell();
+    Emit32(out, NumBuckets);
+    Emit32(out, NumEntries);
+    for (unsigned i = 0; i < NumBuckets; ++i) Emit32(out, Buckets[i].off);
+    
+    return TableOff;
+  }
+  
+  OnDiskChainedHashTableGenerator() {
+    NumEntries = 0;
+    NumBuckets = 64;    
+    // Note that we do not need to run the constructors of the individual
+    // Bucket objects since 'calloc' returns bytes that are all 0.
+    Buckets = (Bucket*) std::calloc(NumBuckets, sizeof(Bucket));
+  }
+  
+  ~OnDiskChainedHashTableGenerator() {
+    std::free(Buckets);
+  }
+};
+
+template<typename Info>
+class OnDiskChainedHashTable {
+  const unsigned NumBuckets;
+  const unsigned NumEntries;
+  const unsigned char* const Buckets;
+  const unsigned char* const Base;
+  Info InfoObj;
+
+public:
+  typedef typename Info::internal_key_type internal_key_type;
+  typedef typename Info::external_key_type external_key_type;
+  typedef typename Info::data_type         data_type;
+  
+  OnDiskChainedHashTable(unsigned numBuckets, unsigned numEntries,
+                         const unsigned char* buckets,
+                         const unsigned char* base,
+                         const Info &InfoObj = Info())
+    : NumBuckets(numBuckets), NumEntries(numEntries),
+      Buckets(buckets), Base(base), InfoObj(InfoObj) {
+        assert((reinterpret_cast<uintptr_t>(buckets) & 0x3) == 0 &&
+               "'buckets' must have a 4-byte alignment");
+      }
+
+  unsigned getNumBuckets() const { return NumBuckets; }
+  unsigned getNumEntries() const { return NumEntries; }
+  const unsigned char* getBase() const { return Base; }
+  const unsigned char* getBuckets() const { return Buckets; }
+
+  bool isEmpty() const { return NumEntries == 0; }
+  
+  class iterator {
+    internal_key_type key;
+    const unsigned char* const data;
+    const unsigned len;
+    Info *InfoObj;
+  public:
+    iterator() : data(0), len(0) {}
+    iterator(const internal_key_type k, const unsigned char* d, unsigned l,
+             Info *InfoObj)
+      : key(k), data(d), len(l), InfoObj(InfoObj) {}
+    
+    data_type operator*() const { return InfoObj->ReadData(key, data, len); }    
+    bool operator==(const iterator& X) const { return X.data == data; }    
+    bool operator!=(const iterator& X) const { return X.data != data; }
+  };    
+  
+  iterator find(const external_key_type& eKey, Info *InfoPtr = 0) {
+    if (!InfoPtr)
+      InfoPtr = &InfoObj;
+
+    using namespace io;
+    const internal_key_type& iKey = Info::GetInternalKey(eKey);
+    unsigned key_hash = Info::ComputeHash(iKey);
+    
+    // Each bucket is just a 32-bit offset into the hash table file.
+    unsigned idx = key_hash & (NumBuckets - 1);
+    const unsigned char* Bucket = Buckets + sizeof(uint32_t)*idx;
+    
+    unsigned offset = ReadLE32(Bucket);
+    if (offset == 0) return iterator(); // Empty bucket.
+    const unsigned char* Items = Base + offset;
+    
+    // 'Items' starts with a 16-bit unsigned integer representing the
+    // number of items in this bucket.
+    unsigned len = ReadUnalignedLE16(Items);
+    
+    for (unsigned i = 0; i < len; ++i) {
+      // Read the hash.
+      uint32_t item_hash = ReadUnalignedLE32(Items);
+      
+      // Determine the length of the key and the data.
+      const std::pair<unsigned, unsigned>& L = Info::ReadKeyDataLength(Items);      
+      unsigned item_len = L.first + L.second;
+
+      // Compare the hashes.  If they are not the same, skip the entry entirely.
+      if (item_hash != key_hash) {
+        Items += item_len;
+        continue;
+      }
+      
+      // Read the key.
+      const internal_key_type& X =
+        InfoPtr->ReadKey((const unsigned char* const) Items, L.first);
+
+      // If the key doesn't match just skip reading the value.
+      if (!Info::EqualKey(X, iKey)) {
+        Items += item_len;
+        continue;
+      }
+      
+      // The key matches!
+      return iterator(X, Items + L.first, L.second, InfoPtr);
+    }
+    
+    return iterator();
+  }
+  
+  iterator end() const { return iterator(); }
+  
+  
+  static OnDiskChainedHashTable* Create(const unsigned char* buckets,
+                                        const unsigned char* const base,
+                                        const Info &InfoObj = Info()) {
+    using namespace io;
+    assert(buckets > base);
+    assert((reinterpret_cast<uintptr_t>(buckets) & 0x3) == 0 &&
+           "buckets should be 4-byte aligned.");
+    
+    unsigned numBuckets = ReadLE32(buckets);
+    unsigned numEntries = ReadLE32(buckets);
+    return new OnDiskChainedHashTable<Info>(numBuckets, numEntries, buckets,
+                                            base, InfoObj);
+  }  
+};
+
+} // end namespace clang
+
+#endif