Switch the Linux minidump writer to use MDCVInfoELF for CV data.

src/common/memory.h

Index: src/common/memory.h
diff --git a/src/common/memory.h b/src/common/memory.h
index d6aa137d35c0fdb16e4af7bff2a0c5a1aea82be8..16a612b8cf36761f7179f897a1d01c3a716139af 100644
--- a/src/common/memory.h
+++ b/src/common/memory.h
@@ -64,7 +64,8 @@ class PageAllocator {
       : page_size_(getpagesize()),
         last_(NULL),
         current_page_(NULL),
-        page_offset_(0) {
+        page_offset_(0),
+        pages_allocated_(0) {
   }
 
   ~PageAllocator() {
@@ -112,6 +113,8 @@ class PageAllocator {
     return false;
   }
 
+  unsigned long pages_allocated() { return pages_allocated_; }
+
  private:
   uint8_t *GetNPages(size_t num_pages) {
 #if defined(__x86_64__) || defined(__aarch64__) || defined(__aarch64__) || \
@@ -136,6 +139,8 @@ class PageAllocator {
     header->num_pages = num_pages;
     last_ = header;
 
+    pages_allocated_ += num_pages;
+
     return reinterpret_cast<uint8_t*>(a);
   }
 
@@ -157,6 +162,7 @@ class PageAllocator {
   PageHeader *last_;
   uint8_t *current_page_;
   size_t page_offset_;
+  unsigned long pages_allocated_;
 };
 
 // Wrapper to use with STL containers
@@ -165,12 +171,30 @@ struct PageStdAllocator : public std::allocator<T> {
   typedef typename std::allocator<T>::pointer pointer;
   typedef typename std::allocator<T>::size_type size_type;
 
-  explicit PageStdAllocator(PageAllocator& allocator): allocator_(allocator) {}
+  explicit PageStdAllocator(PageAllocator& allocator) : allocator_(allocator),
+                                                        stackdata_(NULL),
+                                                        stackdata_size_(0)
+  {}
+
   template <class Other> PageStdAllocator(const PageStdAllocator<Other>& other)
-      : allocator_(other.allocator_) {}
+      : allocator_(other.allocator_),
+        stackdata_(nullptr),
+        stackdata_size_(0)
+  {}
+
+  explicit PageStdAllocator(PageAllocator& allocator,
+                            pointer stackdata,
+                            size_type stackdata_size) : allocator_(allocator),
+      stackdata_(stackdata),
+      stackdata_size_(stackdata_size)
+  {}
 
   inline pointer allocate(size_type n, const void* = 0) {
-    return static_cast<pointer>(allocator_.Alloc(sizeof(T) * n));
+    const size_type size = sizeof(T) * n;
+    if (size <= stackdata_size_) {
+      return stackdata_;
+    }
+    return static_cast<pointer>(allocator_.Alloc(size));
   }
 
   inline void deallocate(pointer, size_type) {
@@ -188,6 +212,8 @@ struct PageStdAllocator : public std::allocator<T> {
   template<typename Other> friend struct PageStdAllocator;
 
   PageAllocator& allocator_;
+  pointer stackdata_;
+  size_type stackdata_size_;
 };
 
 // A wasteful vector is a std::vector, except that it allocates memory from a
@@ -200,6 +226,24 @@ class wasteful_vector : public std::vector<T, PageStdAllocator<T> > {
       : std::vector<T, PageStdAllocator<T> >(PageStdAllocator<T>(*allocator)) {
     std::vector<T, PageStdAllocator<T> >::reserve(size_hint);
   }
+ protected:
+  wasteful_vector(PageStdAllocator<T> allocator)
+      : std::vector<T, PageStdAllocator<T> >(allocator) {}
+};
+
+// auto_wasteful_vector allocates space on the stack for N entries to avoid
+// using the PageAllocator for small data, while still allowing for larger data.
+template<class T, unsigned int N>
+class auto_wasteful_vector : public wasteful_vector<T> {
+ T stackdata_[N];
+ public:
+  auto_wasteful_vector(PageAllocator* allocator)
+      : wasteful_vector<T>(
+            PageStdAllocator<T>(*allocator,
+                                &stackdata_[0],
+                                sizeof(stackdata_))) {
+    std::vector<T, PageStdAllocator<T> >::reserve(N);
+  }
 };
 
 }  // namespace google_breakpad