Merged third_party/tcmalloc/vendor/src(google-perftools r87) into...

third_party/tcmalloc/chromium/src/tcmalloc.cc

Index: third_party/tcmalloc/chromium/src/tcmalloc.cc
===================================================================
--- third_party/tcmalloc/chromium/src/tcmalloc.cc	(revision 41942)
+++ third_party/tcmalloc/chromium/src/tcmalloc.cc	(working copy)
@@ -124,7 +124,6 @@
 #include "linked_list.h"
 #include "maybe_threads.h"
 #include "page_heap.h"
-#include "page_heap_allocator.h"
 #include "pagemap.h"
 #include "span.h"
 #include "static_vars.h"
@@ -136,8 +135,8 @@
 # define WIN32_DO_PATCHING 1
 #endif
 
+using std::max;
 using tcmalloc::PageHeap;
-using tcmalloc::PageHeapAllocator;
 using tcmalloc::SizeMap;
 using tcmalloc::Span;
 using tcmalloc::StackTrace;
@@ -229,23 +228,30 @@
       ATTRIBUTE_SECTION(google_malloc);
   void* tc_newarray_nothrow(size_t size, const std::nothrow_t&) __THROW
       ATTRIBUTE_SECTION(google_malloc);
-}
+  // Surprisingly, compilers use a nothrow-delete internally.  See, eg:
+  //   http://www.dinkumware.com/manuals/?manual=compleat&page=new.html
+  void tc_delete_nothrow(void* ptr, const std::nothrow_t&) __THROW
+      ATTRIBUTE_SECTION(google_malloc);
+  void tc_deletearray_nothrow(void* ptr, const std::nothrow_t&) __THROW
+      ATTRIBUTE_SECTION(google_malloc);
+}  // extern "C"
 
 // Override the libc functions to prefer our own instead.  This comes
 // first so code in tcmalloc.cc can use the overridden versions.  One
 // exception: in windows, by default, we patch our code into these
 // functions (via src/windows/patch_function.cc) rather than override
 // them.  In that case, we don't want to do this overriding here.
-#ifndef WIN32_DO_PATCHING
+#if !defined(WIN32_DO_PATCHING) && !defined(TCMALLOC_FOR_DEBUGALLOCATION)
 
 // TODO(mbelshe):  Turn off TCMalloc's symbols for libc.  We do that
 //                 elsewhere.
-#if 0
+#ifndef _WIN32
 
 #if defined(__GNUC__) && !defined(__MACH__)
   // Potentially faster variants that use the gcc alias extension.
-  // Mach-O (Darwin) does not support weak aliases, hence the __MACH__ check.
   // FreeBSD does support aliases, but apparently not correctly. :-(
+  // NOTE: we make many of these symbols weak, but do so in the makefile
+  //       (via objcopy -W) and not here.  That ends up being more portable.
 # define ALIAS(x) __attribute__ ((alias (x)))
 void* operator new(size_t size)                  ALIAS("tc_new");
 void operator delete(void* p) __THROW            ALIAS("tc_delete");
@@ -255,6 +261,10 @@
                                                  ALIAS("tc_new_nothrow");
 void* operator new[](size_t size, const std::nothrow_t&) __THROW
                                                  ALIAS("tc_newarray_nothrow");
+void operator delete(void* size, const std::nothrow_t&) __THROW
+                                                 ALIAS("tc_delete_nothrow");
+void operator delete[](void* size, const std::nothrow_t&) __THROW
+                                                 ALIAS("tc_deletearray_nothrow");
 extern "C" {
   void* malloc(size_t size) __THROW              ALIAS("tc_malloc");
   void  free(void* ptr) __THROW                  ALIAS("tc_free");
@@ -271,26 +281,8 @@
 #ifdef HAVE_STRUCT_MALLINFO
   struct mallinfo mallinfo(void) __THROW         ALIAS("tc_mallinfo");
 #endif
-  // Some library routines on RedHat 9 allocate memory using malloc()
-  // and free it using __libc_free() (or vice-versa).  Since we provide
-  // our own implementations of malloc/free, we need to make sure that
-  // the __libc_XXX variants (defined as part of glibc) also point to
-  // the same implementations.
-# if defined(__GLIBC__)
-  void* __libc_malloc(size_t size)               ALIAS("tc_malloc");
-  void  __libc_free(void* ptr)                   ALIAS("tc_free");
-  void* __libc_realloc(void* ptr, size_t size)   ALIAS("tc_realloc");
-  void* __libc_calloc(size_t n, size_t size)     ALIAS("tc_calloc");
-  void  __libc_cfree(void* ptr)                  ALIAS("tc_cfree");
-  void* __libc_memalign(size_t align, size_t s)  ALIAS("tc_memalign");
-  void* __libc_valloc(size_t size)               ALIAS("tc_valloc");
-  void* __libc_pvalloc(size_t size)              ALIAS("tc_pvalloc");
-  int __posix_memalign(void** r, size_t a, size_t s) ALIAS("tc_posix_memalign");
-# define HAVE_ALIASED___LIBC 1
-# endif  // #if defined(__GLIBC__)
 }   // extern "C"
-# undef ALIAS
-#else
+#else  // #if defined(__GNUC__) && !defined(__MACH__)
 // Portable wrappers
 void* operator new(size_t size)                  { return tc_new(size);       }
 void operator delete(void* p) __THROW            { tc_delete(p);              }
@@ -302,6 +294,12 @@
 void* operator new[](size_t size, const std::nothrow_t& nt) __THROW {
   return tc_newarray_nothrow(size, nt);
 }
+void operator delete(void* ptr, const std::nothrow_t& nt) __THROW {
+  return tc_delete_nothrow(ptr, nt);
+}
+void operator delete[](void* ptr, const std::nothrow_t& nt) __THROW {
+  return tc_deletearray_nothrow(ptr, nt);
+}
 extern "C" {
   void* malloc(size_t s) __THROW                 { return tc_malloc(s);       }
   void  free(void* p) __THROW                    { tc_free(p);                }
@@ -319,11 +317,27 @@
 #ifdef HAVE_STRUCT_MALLINFO
   struct mallinfo mallinfo(void) __THROW         { return tc_mallinfo();      }
 #endif
-}  // extern C
+}  // extern "C"
 #endif  // #if defined(__GNUC__)
 
-#ifndef HAVE_ALIASED___LIBC
+// Some library routines on RedHat 9 allocate memory using malloc()
+// and free it using __libc_free() (or vice-versa).  Since we provide
+// our own implementations of malloc/free, we need to make sure that
+// the __libc_XXX variants (defined as part of glibc) also point to
+// the same implementations.
+#ifdef __GLIBC__       // only glibc defines __libc_*
 extern "C" {
+#ifdef ALIAS
+  void* __libc_malloc(size_t size)               ALIAS("tc_malloc");
+  void  __libc_free(void* ptr)                   ALIAS("tc_free");
+  void* __libc_realloc(void* ptr, size_t size)   ALIAS("tc_realloc");
+  void* __libc_calloc(size_t n, size_t size)     ALIAS("tc_calloc");
+  void  __libc_cfree(void* ptr)                  ALIAS("tc_cfree");
+  void* __libc_memalign(size_t align, size_t s)  ALIAS("tc_memalign");
+  void* __libc_valloc(size_t size)               ALIAS("tc_valloc");
+  void* __libc_pvalloc(size_t size)              ALIAS("tc_pvalloc");
+  int __posix_memalign(void** r, size_t a, size_t s) ALIAS("tc_posix_memalign");
+#else  // #ifdef ALIAS
   void* __libc_malloc(size_t size)               { return malloc(size);       }
   void  __libc_free(void* ptr)                   { free(ptr);                 }
   void* __libc_realloc(void* ptr, size_t size)   { return realloc(ptr, size); }
@@ -335,19 +349,25 @@
   int __posix_memalign(void** r, size_t a, size_t s) {
     return posix_memalign(r, a, s);
   }
+#endif  // #ifdef ALIAS
 }   // extern "C"
-#endif  // #ifndef HAVE_ALIASED___LIBC
+#endif  // ifdef __GLIBC__
 
-#endif  // #ifdef 0
+#endif  // #ifndef _WIN32
+#undef ALIAS
 
-#endif  // #ifndef WIN32_DO_PATCHING
+#endif  // #ifndef(WIN32_DO_PATCHING) && ndef(TCMALLOC_FOR_DEBUGALLOCATION)
 
 
 // ----------------------- IMPLEMENTATION -------------------------------
 
-// These routines are called by free(), realloc(), etc. if the pointer is
-// invalid.  This is a cheap (source-editing required) kind of exception
-// handling for these routines.
+static int tc_new_mode = 0;  // See tc_set_new_mode().
+
+// Routines such as free() and realloc() catch some erroneous pointers
+// passed to them, and invoke the below when they do.  (An erroneous pointer
+// won't be caught if it's within a valid span or a stale span for which
+// the pagemap cache has a non-zero sizeclass.) This is a cheap (source-editing
+// required) kind of exception handling for these routines.
 namespace {
 void InvalidFree(void* ptr) {
   CRASH("Attempt to free invalid pointer: %p\n", ptr);
@@ -366,13 +386,11 @@
 
 // Extract interesting stats
 struct TCMallocStats {
-  uint64_t system_bytes;        // Bytes alloced from system
-  uint64_t committed_bytes;     // Bytes alloced and committed from system
-  uint64_t thread_bytes;        // Bytes in thread caches
-  uint64_t central_bytes;       // Bytes in central cache
-  uint64_t transfer_bytes;      // Bytes in central transfer cache
-  uint64_t pageheap_bytes;      // Bytes in page heap
-  uint64_t metadata_bytes;      // Bytes alloced for metadata
+  uint64_t thread_bytes;      // Bytes in thread caches
+  uint64_t central_bytes;     // Bytes in central cache
+  uint64_t transfer_bytes;    // Bytes in central transfer cache
+  uint64_t metadata_bytes;    // Bytes alloced for metadata
+  PageHeap::Stats pageheap;   // Stats from page heap
 };
 
 // Get stats into "r".  Also get per-size-class counts if class_count != NULL
@@ -394,14 +412,8 @@
   { // scope
     SpinLockHolder h(Static::pageheap_lock());
     ThreadCache::GetThreadStats(&r->thread_bytes, class_count);
-  }
-
-  { //scope
-    SpinLockHolder h(Static::pageheap_lock());
-    r->system_bytes = Static::pageheap()->SystemBytes();
-    r->committed_bytes = Static::pageheap()->CommittedBytes();
     r->metadata_bytes = tcmalloc::metadata_system_bytes();
-    r->pageheap_bytes = Static::pageheap()->FreeBytes();
+    r->pageheap = Static::pageheap()->stats();
   }
 }
 
@@ -413,8 +425,9 @@
 
   static const double MB = 1048576.0;
 
-  const uint64_t bytes_in_use = stats.system_bytes
-                                - stats.pageheap_bytes
+  const uint64_t bytes_in_use = stats.pageheap.system_bytes
+                                - stats.pageheap.free_bytes
+                                - stats.pageheap.unmapped_bytes
                                 - stats.central_bytes
                                 - stats.transfer_bytes
                                 - stats.thread_bytes;
@@ -422,13 +435,15 @@
   out->printf("WASTE: %7.1f MB committed but not used\n"
               "WASTE: %7.1f MB bytes committed, %7.1f MB bytes in use\n"
               "WASTE: committed/used ratio of %f\n",
-              (stats.committed_bytes - bytes_in_use) / MB,
-              stats.committed_bytes / MB,
+              (stats.pageheap.committed_bytes - bytes_in_use) / MB,
+              stats.pageheap.committed_bytes / MB,
               bytes_in_use / MB,
-              stats.committed_bytes / static_cast<double>(bytes_in_use));
+              stats.pageheap.committed_bytes / static_cast<double>(bytes_in_use));
 
   if (level >= 2) {
     out->printf("------------------------------------------------\n");
+    out->printf("Size class breakdown\n");
+    out->printf("------------------------------------------------\n");
     uint64_t cumulative = 0;
     for (int cl = 0; cl < kNumClasses; ++cl) {
       if (class_count[cl] > 0) {
@@ -456,6 +471,7 @@
               "MALLOC: %12" PRIu64 " (%7.1f MB) Bytes committed\n"
               "MALLOC: %12" PRIu64 " (%7.1f MB) Bytes in use by application\n"
               "MALLOC: %12" PRIu64 " (%7.1f MB) Bytes free in page heap\n"
+              "MALLOC: %12" PRIu64 " (%7.1f MB) Bytes unmapped in page heap\n"
               "MALLOC: %12" PRIu64 " (%7.1f MB) Bytes free in central cache\n"
               "MALLOC: %12" PRIu64 " (%7.1f MB) Bytes free in transfer cache\n"
               "MALLOC: %12" PRIu64 " (%7.1f MB) Bytes free in thread caches\n"
@@ -463,10 +479,11 @@
               "MALLOC: %12" PRIu64 "              Thread heaps in use\n"
               "MALLOC: %12" PRIu64 " (%7.1f MB) Metadata allocated\n"
               "------------------------------------------------\n",
-              stats.system_bytes, stats.system_bytes / MB,
-              stats.committed_bytes, stats.committed_bytes / MB,
+              stats.pageheap.system_bytes, stats.pageheap.system_bytes / MB,
+              stats.pageheap.committed_bytes, stats.pageheap.committed_bytes / MB,
               bytes_in_use, bytes_in_use / MB,
-              stats.pageheap_bytes, stats.pageheap_bytes / MB,
+              stats.pageheap.free_bytes, stats.pageheap.free_bytes / MB,
+              stats.pageheap.unmapped_bytes, stats.pageheap.unmapped_bytes / MB,
               stats.central_bytes, stats.central_bytes / MB,
               stats.transfer_bytes, stats.transfer_bytes / MB,
               stats.thread_bytes, stats.thread_bytes / MB,
@@ -530,9 +547,50 @@
   return result;
 }
 
+static void IterateOverRanges(void* arg, MallocExtension::RangeFunction func) {
+  PageID page = 1;  // Some code may assume that page==0 is never used
+  bool done = false;
+  while (!done) {
+    // Accumulate a small number of ranges in a local buffer
+    static const int kNumRanges = 16;
+    static base::MallocRange ranges[kNumRanges];
+    int n = 0;
+    {
+      SpinLockHolder h(Static::pageheap_lock());
+      while (n < kNumRanges) {
+        if (!Static::pageheap()->GetNextRange(page, &ranges[n])) {
+          done = true;
+          break;
+        } else {
+          uintptr_t limit = ranges[n].address + ranges[n].length;
+          page = (limit + kPageSize - 1) >> kPageShift;
+          n++;
+        }
+      }
+    }
+
+    for (int i = 0; i < n; i++) {
+      (*func)(arg, &ranges[i]);
+    }
+  }
+}
+
 // TCMalloc's support for extra malloc interfaces
 class TCMallocImplementation : public MallocExtension {
+ private:
+  // ReleaseToSystem() might release more than the requested bytes because
+  // the page heap releases at the span granularity, and spans are of wildly
+  // different sizes.  This member keeps track of the extra bytes bytes
+  // released so that the app can periodically call ReleaseToSystem() to
+  // release memory at a constant rate.
+  // NOTE: Protected by Static::pageheap_lock().
+  size_t extra_bytes_released_;
+
  public:
+  TCMallocImplementation()
+      : extra_bytes_released_(0) {
+  }
+
   virtual void GetStats(char* buffer, int buffer_length) {
     ASSERT(buffer_length > 0);
     TCMalloc_Printer printer(buffer, buffer_length);
@@ -562,42 +620,54 @@
     return DumpHeapGrowthStackTraces();
   }
 
+  virtual void Ranges(void* arg, RangeFunction func) {
+    IterateOverRanges(arg, func);
+  }
+
   virtual bool GetNumericProperty(const char* name, size_t* value) {
     ASSERT(name != NULL);
 
     if (strcmp(name, "generic.current_allocated_bytes") == 0) {
       TCMallocStats stats;
       ExtractStats(&stats, NULL);
-      *value = stats.system_bytes
+      *value = stats.pageheap.system_bytes
                - stats.thread_bytes
                - stats.central_bytes
                - stats.transfer_bytes
-               - stats.pageheap_bytes;
+               - stats.pageheap.free_bytes
+               - stats.pageheap.unmapped_bytes;
       return true;
     }
 
     if (strcmp(name, "generic.heap_size") == 0) {
       TCMallocStats stats;
       ExtractStats(&stats, NULL);
-      *value = stats.system_bytes;
+      *value = stats.pageheap.system_bytes;
       return true;
     }
 
-    if (strcmp(name, "generic.committed_bytes") == 0) {
-      TCMallocStats stats;
-      ExtractStats(&stats, NULL);
-      *value = stats.committed_bytes + stats.metadata_bytes;
+    if (strcmp(name, "tcmalloc.slack_bytes") == 0) {
+      // We assume that bytes in the page heap are not fragmented too
+      // badly, and are therefore available for allocation without
+      // growing the pageheap system byte count.
+      SpinLockHolder l(Static::pageheap_lock());
+      PageHeap::Stats stats = Static::pageheap()->stats();
+      *value = stats.free_bytes + stats.unmapped_bytes;
       return true;
     }
 
-    if (strcmp(name, "tcmalloc.slack_bytes") == 0) {
-      // We assume that bytes in the page heap are not fragmented too
-      // badly, and are therefore available for allocation.
+    if (strcmp(name, "tcmalloc.pageheap_free_bytes") == 0) {
       SpinLockHolder l(Static::pageheap_lock());
-      *value = Static::pageheap()->FreeBytes();
+      *value = Static::pageheap()->stats().free_bytes;
       return true;
     }
 
+    if (strcmp(name, "tcmalloc.pageheap_unmapped_bytes") == 0) {
+      SpinLockHolder l(Static::pageheap_lock());
+      *value = Static::pageheap()->stats().unmapped_bytes;
+      return true;
+    }
+
     if (strcmp(name, "tcmalloc.max_total_thread_cache_bytes") == 0) {
       SpinLockHolder l(Static::pageheap_lock());
       *value = ThreadCache::overall_thread_cache_size();
@@ -630,9 +700,31 @@
     ThreadCache::BecomeIdle();
   }
 
-  virtual void ReleaseFreeMemory() {
+  virtual void MarkThreadBusy();  // Implemented below
+
+  virtual void ReleaseToSystem(size_t num_bytes) {
     SpinLockHolder h(Static::pageheap_lock());
-    Static::pageheap()->ReleaseFreePages();
+    if (num_bytes <= extra_bytes_released_) {
+      // We released too much on a prior call, so don't release any
+      // more this time.
+      extra_bytes_released_ = extra_bytes_released_ - num_bytes;
+      return;
+    }
+    num_bytes = num_bytes - extra_bytes_released_;
+    // num_bytes might be less than one page.  If we pass zero to
+    // ReleaseAtLeastNPages, it won't do anything, so we release a whole
+    // page now and let extra_bytes_released_ smooth it out over time.
+    Length num_pages = max<Length>(num_bytes >> kPageShift, 1);
+    size_t bytes_released = Static::pageheap()->ReleaseAtLeastNPages(
+        num_pages) << kPageShift;
+    if (bytes_released > num_bytes) {
+      extra_bytes_released_ = bytes_released - num_bytes;
+    } else {
+      // The PageHeap wasn't able to release num_bytes.  Don't try to
+      // compensate with a big release next time.  Specifically,
+      // ReleaseFreeMemory() calls ReleaseToSystem(LONG_MAX).
+      extra_bytes_released_ = 0;
+    }
   }
 
   virtual void SetMemoryReleaseRate(double rate) {
@@ -681,9 +773,9 @@
     // patch the windows VirtualAlloc, etc.
     PatchWindowsFunctions();    // defined in windows/patch_functions.cc
 #endif
-    free(malloc(1));
+    tc_free(tc_malloc(1));
     ThreadCache::InitTSD();
-    free(malloc(1));
+    tc_free(tc_malloc(1));
     MallocExtension::Register(new TCMallocImplementation);
   }
 }
@@ -778,6 +870,24 @@
 
 namespace {
 
+inline void* cpp_alloc(size_t size, bool nothrow);
+inline void* do_malloc(size_t size);
+
+// TODO(willchan): Investigate whether or not inlining this much is harmful to
+// performance.
+// This is equivalent to do_malloc() except when tc_new_mode is set to true.
+// Otherwise, it will run the std::new_handler if set.
+inline void* do_malloc_or_cpp_alloc(size_t size) {
+  return tc_new_mode ? cpp_alloc(size, true) : do_malloc(size);
+}
+
+void* cpp_memalign(size_t align, size_t size);
+void* do_memalign(size_t align, size_t size);
+
+inline void* do_memalign_or_cpp_memalign(size_t align, size_t size) {
+  return tc_new_mode ? cpp_memalign(align, size) : do_memalign(align, size);
+}
+
 // Helper for do_malloc().
 inline void* do_malloc_pages(Length num_pages) {
   Span *span;
@@ -828,7 +938,7 @@
   const size_t size = n * elem_size;
   if (elem_size != 0 && size / elem_size != n) return NULL;
 
-  void* result = do_malloc(size);
+  void* result = do_malloc_or_cpp_alloc(size);
   if (result != NULL) {
     memset(result, 0, size);
   }
@@ -937,11 +1047,11 @@
     void* new_ptr = NULL;
 
     if (new_size > old_size && new_size < lower_bound_to_grow) {
-      new_ptr = do_malloc(lower_bound_to_grow);
+      new_ptr = do_malloc_or_cpp_alloc(lower_bound_to_grow);
     }
     if (new_ptr == NULL) {
       // Either new_size is not a tiny increment, or last do_malloc failed.
-      new_ptr = do_malloc(new_size);
+      new_ptr = do_malloc_or_cpp_alloc(new_size);
     }
     if (new_ptr == NULL) {
       return NULL;
@@ -1062,16 +1172,18 @@
 
   // Unfortunately, the struct contains "int" field, so some of the
   // size values will be truncated.
-  info.arena     = static_cast<int>(stats.system_bytes);
+  info.arena     = static_cast<int>(stats.pageheap.system_bytes);
   info.fsmblks   = static_cast<int>(stats.thread_bytes
                                     + stats.central_bytes
                                     + stats.transfer_bytes);
-  info.fordblks  = static_cast<int>(stats.pageheap_bytes);
-  info.uordblks  = static_cast<int>(stats.system_bytes
+  info.fordblks  = static_cast<int>(stats.pageheap.free_bytes +
+                                    stats.pageheap.unmapped_bytes);
+  info.uordblks  = static_cast<int>(stats.pageheap.system_bytes
                                     - stats.thread_bytes
                                     - stats.central_bytes
                                     - stats.transfer_bytes
-                                    - stats.pageheap_bytes);
+                                    - stats.pageheap.free_bytes
+                                    - stats.pageheap.unmapped_bytes);
 
   return info;
 }
@@ -1127,6 +1239,52 @@
   }
 }
 
+void* cpp_memalign(size_t align, size_t size) {
+  for (;;) {
+    void* p = do_memalign(align, size);
+#ifdef PREANSINEW
+    return p;
+#else
+    if (p == NULL) {  // allocation failed
+      // Get the current new handler.  NB: this function is not
+      // thread-safe.  We make a feeble stab at making it so here, but
+      // this lock only protects against tcmalloc interfering with
+      // itself, not with other libraries calling set_new_handler.
+      std::new_handler nh;
+      {
+        SpinLockHolder h(&set_new_handler_lock);
+        nh = std::set_new_handler(0);
+        (void) std::set_new_handler(nh);
+      }
+#if (defined(__GNUC__) && !defined(__EXCEPTIONS)) || (defined(_HAS_EXCEPTIONS) && !_HAS_EXCEPTIONS)
+      if (nh) {
+        // Since exceptions are disabled, we don't really know if new_handler
+        // failed.  Assume it will abort if it fails.
+        (*nh)();
+        continue;
+      }
+      return 0;
+#else
+      // If no new_handler is established, the allocation failed.
+      if (!nh)
+        return 0;
+
+      // Otherwise, try the new_handler.  If it returns, retry the
+      // allocation.  If it throws std::bad_alloc, fail the allocation.
+      // if it throws something else, don't interfere.
+      try {
+        (*nh)();
+      } catch (const std::bad_alloc&) {
+        return p;
+      }
+#endif  // (defined(__GNUC__) && !defined(__EXCEPTIONS)) || (defined(_HAS_EXCEPTIONS) && !_HAS_EXCEPTIONS)
+    } else {  // allocation success
+      return p;
+    }
+#endif  // PREANSINEW
+  }
+}
+
 }  // end unnamed namespace
 
 // As promised, the definition of this function, declared above.
@@ -1134,41 +1292,56 @@
   return GetSizeWithCallback(ptr, &InvalidGetAllocatedSize);
 }
 
+void TCMallocImplementation::MarkThreadBusy() {
+  // Allocate to force the creation of a thread cache, but avoid
+  // invoking any hooks.
+  do_free(do_malloc(0));
+}
+
 //-------------------------------------------------------------------
 // Exported routines
 //-------------------------------------------------------------------
 
+extern "C" PERFTOOLS_DLL_DECL const char* tc_version(
+    int* major, int* minor, const char** patch) __THROW {
+  if (major) *major = TC_VERSION_MAJOR;
+  if (minor) *minor = TC_VERSION_MINOR;
+  if (patch) *patch = TC_VERSION_PATCH;
+  return TC_VERSION_STRING;
+}
+
 // CAVEAT: The code structure below ensures that MallocHook methods are always
 //         called from the stack frame of the invoked allocation function.
 //         heap-checker.cc depends on this to start a stack trace from
 //         the call to the (de)allocation function.
 
-static int tc_new_mode = 0;  // See tc_set_new_mode().
-extern "C" void* tc_malloc(size_t size) __THROW {
-  void* result = (tc_new_mode ? cpp_alloc(size, false) : do_malloc(size));
+extern "C" PERFTOOLS_DLL_DECL void* tc_malloc(size_t size) __THROW {
+  void* result = do_malloc_or_cpp_alloc(size);
   MallocHook::InvokeNewHook(result, size);
   return result;
 }
 
-extern "C" void tc_free(void* ptr) __THROW {
+extern "C" PERFTOOLS_DLL_DECL void tc_free(void* ptr) __THROW {
   MallocHook::InvokeDeleteHook(ptr);
   do_free(ptr);
 }
 
-extern "C" void* tc_calloc(size_t n, size_t elem_size) __THROW {
+extern "C" PERFTOOLS_DLL_DECL void* tc_calloc(size_t n,
+                                              size_t elem_size) __THROW {
   void* result = do_calloc(n, elem_size);
   MallocHook::InvokeNewHook(result, n * elem_size);
   return result;
 }
 
-extern "C" void tc_cfree(void* ptr) __THROW {
+extern "C" PERFTOOLS_DLL_DECL void tc_cfree(void* ptr) __THROW {
   MallocHook::InvokeDeleteHook(ptr);
   do_free(ptr);
 }
 
-extern "C" void* tc_realloc(void* old_ptr, size_t new_size) __THROW {
+extern "C" PERFTOOLS_DLL_DECL void* tc_realloc(void* old_ptr,
+                                               size_t new_size) __THROW {
   if (old_ptr == NULL) {
-    void* result = do_malloc(new_size);
+    void* result = do_malloc_or_cpp_alloc(new_size);
     MallocHook::InvokeNewHook(result, new_size);
     return result;
   }
@@ -1180,7 +1353,7 @@
   return do_realloc(old_ptr, new_size);
 }
 
-extern "C" void* tc_new(size_t size) {
+extern "C" PERFTOOLS_DLL_DECL void* tc_new(size_t size) {
   void* p = cpp_alloc(size, false);
   // We keep this next instruction out of cpp_alloc for a reason: when
   // it's in, and new just calls cpp_alloc, the optimizer may fold the
@@ -1191,18 +1364,27 @@
   return p;
 }
 
-extern "C" void* tc_new_nothrow(size_t size, const std::nothrow_t&) __THROW {
+extern "C" PERFTOOLS_DLL_DECL void* tc_new_nothrow(
+    size_t size, const std::nothrow_t&) __THROW {
   void* p = cpp_alloc(size, true);
   MallocHook::InvokeNewHook(p, size);
   return p;
 }
 
-extern "C" void tc_delete(void* p) __THROW {
+extern "C" PERFTOOLS_DLL_DECL void tc_delete(void* p) __THROW {
   MallocHook::InvokeDeleteHook(p);
   do_free(p);
 }
 
-extern "C" void* tc_newarray(size_t size) {
+// Compilers define and use this (via ::operator delete(ptr, nothrow)).
+// But it's really the same as normal delete, so we just do the same thing.
+extern "C" PERFTOOLS_DLL_DECL void tc_delete_nothrow(
+    void* p, const std::nothrow_t&) __THROW {
+  MallocHook::InvokeDeleteHook(p);
+  do_free(p);
+}
+
+extern "C" PERFTOOLS_DLL_DECL void* tc_newarray(size_t size) {
   void* p = cpp_alloc(size, false);
   // We keep this next instruction out of cpp_alloc for a reason: when
   // it's in, and new just calls cpp_alloc, the optimizer may fold the
@@ -1213,32 +1395,40 @@
   return p;
 }
 
-extern "C" void* tc_newarray_nothrow(size_t size, const std::nothrow_t&) __THROW {
+extern "C" PERFTOOLS_DLL_DECL void* tc_newarray_nothrow(
+    size_t size, const std::nothrow_t&) __THROW {
   void* p = cpp_alloc(size, true);
   MallocHook::InvokeNewHook(p, size);
   return p;
 }
 
-extern "C" void tc_deletearray(void* p) __THROW {
+extern "C" PERFTOOLS_DLL_DECL void tc_deletearray(void* p) __THROW {
   MallocHook::InvokeDeleteHook(p);
   do_free(p);
 }
 
-extern "C" void* tc_memalign(size_t align, size_t size) __THROW {
-  void* result = do_memalign(align, size);
+extern "C" PERFTOOLS_DLL_DECL void tc_deletearray_nothrow(
+    void* p, const std::nothrow_t&) __THROW {
+  MallocHook::InvokeDeleteHook(p);
+  do_free(p);
+}
+
+extern "C" PERFTOOLS_DLL_DECL void* tc_memalign(size_t align,
+                                                size_t size) __THROW {
+  void* result = do_memalign_or_cpp_memalign(align, size);
   MallocHook::InvokeNewHook(result, size);
   return result;
 }
 
-extern "C" int tc_posix_memalign(void** result_ptr, size_t align, size_t size)
-    __THROW {
+extern "C" PERFTOOLS_DLL_DECL int tc_posix_memalign(
+    void** result_ptr, size_t align, size_t size) __THROW {
   if (((align % sizeof(void*)) != 0) ||
       ((align & (align - 1)) != 0) ||
       (align == 0)) {
     return EINVAL;
   }
 
-  void* result = do_memalign(align, size);
+  void* result = do_memalign_or_cpp_memalign(align, size);
   MallocHook::InvokeNewHook(result, size);
   if (result == NULL) {
     return ENOMEM;
@@ -1250,33 +1440,36 @@
 
 static size_t pagesize = 0;
 
-extern "C" void* tc_valloc(size_t size) __THROW {
+extern "C" PERFTOOLS_DLL_DECL void* tc_valloc(size_t size) __THROW {
   // Allocate page-aligned object of length >= size bytes
   if (pagesize == 0) pagesize = getpagesize();
-  void* result = do_memalign(pagesize, size);
+  void* result = do_memalign_or_cpp_memalign(pagesize, size);
   MallocHook::InvokeNewHook(result, size);
   return result;
 }
 
-extern "C" void* tc_pvalloc(size_t size) __THROW {
+extern "C" PERFTOOLS_DLL_DECL void* tc_pvalloc(size_t size) __THROW {
   // Round up size to a multiple of pagesize
   if (pagesize == 0) pagesize = getpagesize();
+  if (size == 0) {     // pvalloc(0) should allocate one page, according to
+    size = pagesize;   // http://man.free4web.biz/man3/libmpatrol.3.html
+  }
   size = (size + pagesize - 1) & ~(pagesize - 1);
-  void* result = do_memalign(pagesize, size);
+  void* result = do_memalign_or_cpp_memalign(pagesize, size);
   MallocHook::InvokeNewHook(result, size);
   return result;
 }
 
-extern "C" void tc_malloc_stats(void) __THROW {
+extern "C" PERFTOOLS_DLL_DECL void tc_malloc_stats(void) __THROW {
   do_malloc_stats();
 }
 
-extern "C" int tc_mallopt(int cmd, int value) __THROW {
+extern "C" PERFTOOLS_DLL_DECL int tc_mallopt(int cmd, int value) __THROW {
   return do_mallopt(cmd, value);
 }
 
 #ifdef HAVE_STRUCT_MALLINFO
-extern "C" struct mallinfo tc_mallinfo(void) __THROW {
+extern "C" PERFTOOLS_DLL_DECL struct mallinfo tc_mallinfo(void) __THROW {
   return do_mallinfo();
 }
 #endif
@@ -1286,7 +1479,7 @@
 // If flag is 1, calls to malloc will behave like calls to new,
 // and the std_new_handler will be invoked on failure.
 // Returns the previous mode.
-extern "C" int tc_set_new_mode(int flag) __THROW {
+extern "C" PERFTOOLS_DLL_DECL int tc_set_new_mode(int flag) __THROW {
   int old_mode = tc_new_mode;
   tc_new_mode = flag;
   return old_mode;
@@ -1300,13 +1493,15 @@
 // This function is an exception to the rule of calling MallocHook method
 // from the stack frame of the allocation function;
 // heap-checker handles this special case explicitly.
+#ifndef TCMALLOC_FOR_DEBUGALLOCATION
 static void *MemalignOverride(size_t align, size_t size, const void *caller)
     __THROW ATTRIBUTE_SECTION(google_malloc);
 
 static void *MemalignOverride(size_t align, size_t size, const void *caller)
     __THROW {
-  void* result = do_memalign(align, size);
+  void* result = do_memalign_or_cpp_memalign(align, size);
   MallocHook::InvokeNewHook(result, size);
   return result;
 }
 void *(*__memalign_hook)(size_t, size_t, const void *) = MemalignOverride;
+#endif  // #ifndef TCMALLOC_FOR_DEBUGALLOCATION