Change ExplodedNode to have its NodeGroups all BumpPtrAllocated, avoiding malloc() traffic when adding successors/predecessors to a node. This was done by introducing BumpVector, which is essentially SmallVector with all memory being BumpPtrAllocated (this can certainly be cleaned up or moved into llvm/ADT).

This change yields a 1.8% speed increase when running the analyzer (with -analyzer-store=region) on a small benchmark file.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@83439 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 200 insertions, 0 deletions

diff --git a/include/clang/Analysis/Support/BumpVector.h b/include/clang/Analysis/Support/BumpVector.h
new file mode 100644
index 0000000000..d1c6d4ba4a
--- /dev/null
+++ b/include/clang/Analysis/Support/BumpVector.h
@@ -0,0 +1,200 @@
+//===-- BumpVector.h - Vector-like ADT that uses bump allocation --*- C++ -*-=//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file provides BumpVector, a vector-like ADT whose contents are
+//  allocated from a BumpPtrAllocator.
+//
+//===----------------------------------------------------------------------===//
+
+// FIXME: Most of this is copy-and-paste from SmallVector.h.  We can
+// refactor this core logic into something common that is shared between
+// the two.  The main thing that is different is the allocation strategy.
+
+#ifndef LLVM_CLANG_BUMP_VECTOR
+#define LLVM_CLANG_BUMP_VECTOR
+
+#include "llvm/Support/type_traits.h"
+#include "llvm/Support/Allocator.h"
+#include <algorithm>
+
+namespace clang {
+  
+class BumpVectorContext {
+  llvm::BumpPtrAllocator Alloc;
+public:
+  llvm::BumpPtrAllocator &getAllocator() { return Alloc; }
+};
+  
+template<typename T>
+class BumpVector {
+  T *Begin, *End, *Capacity;
+public:
+  // Default ctor - Initialize to empty.
+  explicit BumpVector(BumpVectorContext &C, unsigned N)
+  : Begin(NULL), End(NULL), Capacity(NULL) {
+    reserve(C, N);
+  }
+  
+  ~BumpVector() {
+    if (llvm::is_class<T>::value) {
+      // Destroy the constructed elements in the vector.
+      destroy_range(Begin, End);
+    }
+  }
+  
+  typedef size_t size_type;
+  typedef ptrdiff_t difference_type;
+  typedef T value_type;
+  typedef T* iterator;
+  typedef const T* const_iterator;
+  
+  typedef std::reverse_iterator<const_iterator>  const_reverse_iterator;
+  typedef std::reverse_iterator<iterator>  reverse_iterator;
+  
+  typedef T& reference;
+  typedef const T& const_reference;
+  typedef T* pointer;
+  typedef const T* const_pointer;
+  
+  // forward iterator creation methods.
+  iterator begin() { return Begin; }
+  const_iterator begin() const { return Begin; }
+  iterator end() { return End; }
+  const_iterator end() const { return End; }
+  
+  // reverse iterator creation methods.
+  reverse_iterator rbegin()            { return reverse_iterator(end()); }
+  const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); }
+  reverse_iterator rend()              { return reverse_iterator(begin()); }
+  const_reverse_iterator rend() const { return const_reverse_iterator(begin());}
+    
+  bool empty() const { return Begin == End; }
+  size_type size() const { return End-Begin; }
+
+  reference operator[](unsigned idx) {
+    assert(Begin + idx < End);
+    return Begin[idx];
+  }
+  const_reference operator[](unsigned idx) const {
+    assert(Begin + idx < End);
+    return Begin[idx];
+  }
+  
+  reference front() {
+    return begin()[0];
+  }
+  const_reference front() const {
+    return begin()[0];
+  }
+  
+  reference back() {
+    return end()[-1];
+  }
+  const_reference back() const {
+    return end()[-1];
+  }
+  
+  void pop_back() {
+    --End;
+    End->~T();
+  }
+  
+  T pop_back_val() {
+    T Result = back();
+    pop_back();
+    return Result;
+  }
+  
+  void clear() {
+    if (llvm::is_class<T>::value) {
+      destroy_range(Begin, End);
+    }
+    End = Begin;
+  }
+  
+  /// data - Return a pointer to the vector's buffer, even if empty().
+  pointer data() {
+    return pointer(Begin);
+  }
+  
+  /// data - Return a pointer to the vector's buffer, even if empty().
+  const_pointer data() const {
+    return const_pointer(Begin);
+  }
+  
+  void push_back(const_reference Elt, BumpVectorContext &C) {
+    if (End < Capacity) {
+    Retry:
+      new (End) T(Elt);
+      ++End;
+      return;
+    }
+    grow(C);
+    goto Retry;    
+  }
+  
+  void reserve(BumpVectorContext &C, unsigned N) {
+    if (unsigned(Capacity-Begin) < N)
+      grow(C, N);
+  }
+
+  /// capacity - Return the total number of elements in the currently allocated
+  /// buffer.
+  size_t capacity() const { return Capacity - Begin; }  
+    
+private:
+  /// grow - double the size of the allocated memory, guaranteeing space for at
+  /// least one more element or MinSize if specified.
+  void grow(BumpVectorContext &C, size_type MinSize = 0);
+  
+  void construct_range(T *S, T *E, const T &Elt) {
+    for (; S != E; ++S)
+      new (S) T(Elt);
+  }
+  
+  void destroy_range(T *S, T *E) {
+    while (S != E) {
+      --E;
+      E->~T();
+    }
+  }
+};
+  
+// Define this out-of-line to dissuade the C++ compiler from inlining it.
+template <typename T>
+void BumpVector<T>::grow(BumpVectorContext &C, size_t MinSize) {
+  size_t CurCapacity = Capacity-Begin;
+  size_t CurSize = size();
+  size_t NewCapacity = 2*CurCapacity;
+  if (NewCapacity < MinSize)
+    NewCapacity = MinSize;
+
+  // Allocate the memory from the BumpPtrAllocator.
+  T *NewElts = C.getAllocator().Allocate<T>(NewCapacity);
+  
+  // Copy the elements over.
+  if (llvm::is_class<T>::value) {
+    std::uninitialized_copy(Begin, End, NewElts);
+    // Destroy the original elements.
+    destroy_range(Begin, End);
+  }
+  else {
+    // Use memcpy for PODs (std::uninitialized_copy optimizes to memmove).
+    memcpy(NewElts, Begin, CurSize * sizeof(T));
+  }
+
+  // For now, leak 'Begin'.  We can add it back to a freelist in
+  // BumpVectorContext.
+  Begin = NewElts;
+  End = NewElts+CurSize;
+  Capacity = Begin+NewCapacity;
+}
+
+} // end: clang namespace
+#endif // end: LLVM_CLANG_BUMP_VECTOR