Merge google-perftools r109 (the current contents of third_party/tcmalloc/vendor)

third_party/tcmalloc/chromium/src/system-alloc.cc

Index: third_party/tcmalloc/chromium/src/system-alloc.cc
===================================================================
--- third_party/tcmalloc/chromium/src/system-alloc.cc	(revision 87277)
+++ third_party/tcmalloc/chromium/src/system-alloc.cc	(working copy)
@@ -31,26 +31,29 @@
 // Author: Sanjay Ghemawat
 
 #include <config.h>
+#include <errno.h>                      // for EAGAIN, errno
+#include <fcntl.h>                      // for open, O_RDWR
+#include <stddef.h>                     // for size_t, NULL, ptrdiff_t
 #if defined HAVE_STDINT_H
-#include <stdint.h>
+#include <stdint.h>                     // for uintptr_t, intptr_t
 #elif defined HAVE_INTTYPES_H
 #include <inttypes.h>
 #else
 #include <sys/types.h>
 #endif
+#ifdef HAVE_MMAP
+#include <sys/mman.h>                   // for munmap, mmap, MADV_DONTNEED, etc
+#endif
 #ifdef HAVE_UNISTD_H
-#include <unistd.h>
+#include <unistd.h>                     // for sbrk, getpagesize, off_t
 #endif
-#include <fcntl.h>    // for open()
-#ifdef HAVE_MMAP
-#include <sys/mman.h>
-#endif
-#include <errno.h>
-#include "system-alloc.h"
+#include <new>                          // for operator new
+#include <google/malloc_extension.h>
+#include "base/basictypes.h"
+#include "base/commandlineflags.h"
+#include "base/spinlock.h"              // for SpinLockHolder, SpinLock, etc
+#include "common.h"
 #include "internal_logging.h"
-#include "base/logging.h"
-#include "base/commandlineflags.h"
-#include "base/spinlock.h"
 
 // On systems (like freebsd) that don't define MAP_ANONYMOUS, use the old
 // form of the name instead.
@@ -73,6 +76,24 @@
 static const bool kDebugMode = true;
 #endif
 
+// Anonymous namespace to avoid name conflicts on "CheckAddressBits".
+namespace {
+
+// Check that no bit is set at position ADDRESS_BITS or higher.
+template <int ADDRESS_BITS> bool CheckAddressBits(uintptr_t ptr) {
+  return (ptr >> ADDRESS_BITS) == 0;
+}
+
+// Specialize for the bit width of a pointer to avoid undefined shift.
+template <> bool CheckAddressBits<8 * sizeof(void*)>(uintptr_t ptr) {
+  return true;
+}
+
+}  // Anonymous namespace to avoid name conflicts on "CheckAddressBits".
+
+COMPILE_ASSERT(kAddressBits <= 8 * sizeof(void*),
+               address_bits_larger_than_pointer_size);
+
 // Structure for discovering alignment
 union MemoryAligner {
   void*  p;
@@ -87,8 +108,10 @@
 static size_t pagesize = 0;
 #endif
 
+// The current system allocator
+SysAllocator* sys_alloc = NULL;
+
 // Configuration parameters.
-
 DEFINE_int32(malloc_devmem_start,
              EnvToInt("TCMALLOC_DEVMEM_START", 0),
              "Physical memory starting location in MB for /dev/mem allocation."
@@ -110,7 +133,7 @@
   SbrkSysAllocator() : SysAllocator() {
   }
   void* Alloc(size_t size, size_t *actual_size, size_t alignment);
-  void DumpStats(TCMalloc_Printer* printer);
+  void FlagsInitialized() {}
 };
 static char sbrk_space[sizeof(SbrkSysAllocator)];
 
@@ -119,7 +142,7 @@
   MmapSysAllocator() : SysAllocator() {
   }
   void* Alloc(size_t size, size_t *actual_size, size_t alignment);
-  void DumpStats(TCMalloc_Printer* printer);
+  void FlagsInitialized() {}
 };
 static char mmap_space[sizeof(MmapSysAllocator)];
 
@@ -128,30 +151,41 @@
   DevMemSysAllocator() : SysAllocator() {
   }
   void* Alloc(size_t size, size_t *actual_size, size_t alignment);
-  void DumpStats(TCMalloc_Printer* printer);
+  void FlagsInitialized() {}
 };
-static char devmem_space[sizeof(DevMemSysAllocator)];
 
-static const int kStaticAllocators = 3;
-// kMaxDynamicAllocators + kStaticAllocators;
-static const int kMaxAllocators = 5;
-static SysAllocator *allocators[kMaxAllocators];
+class DefaultSysAllocator : public SysAllocator {
+ public:
+  DefaultSysAllocator() : SysAllocator() {
+    for (int i = 0; i < kMaxAllocators; i++) {
+      failed_[i] = true;
+      allocs_[i] = NULL;
+    }
+  }
+  void SetChildAllocator(SysAllocator* alloc, unsigned int index,
+                         const char* name) {
+    if (index < kMaxAllocators && alloc != NULL) {
+      allocs_[index] = alloc;
+      failed_[index] = false;
+    }
+  }
+  void* Alloc(size_t size, size_t *actual_size, size_t alignment);
+  void FlagsInitialized() {}
 
-bool RegisterSystemAllocator(SysAllocator *a, int priority) {
-  SpinLockHolder lock_holder(&spinlock);
+ private:
+  static const int kMaxAllocators = 2;
+  bool failed_[kMaxAllocators];
+  SysAllocator* allocs_[kMaxAllocators];
+  const char* names_[kMaxAllocators];
+};
+static char default_space[sizeof(DefaultSysAllocator)];
+static const char sbrk_name[] = "SbrkSysAllocator";
+static const char mmap_name[] = "MmapSysAllocator";
 
-  // No two allocators should have a priority conflict, since the order
-  // is determined at compile time.
-  CHECK_CONDITION(allocators[priority] == NULL);
-  allocators[priority] = a;
-  return true;
-}
 
-
 void* SbrkSysAllocator::Alloc(size_t size, size_t *actual_size,
                               size_t alignment) {
 #ifndef HAVE_SBRK
-  failed_ = true;
   return NULL;
 #else
   // Check if we should use sbrk allocation.
@@ -186,13 +220,11 @@
   //    http://sourceware.org/cgi-bin/cvsweb.cgi/~checkout~/libc/misc/sbrk.c?rev=1.1.2.1&content-type=text/plain&cvsroot=glibc
   // Without this check, sbrk may succeed when it ought to fail.)
   if (reinterpret_cast<intptr_t>(sbrk(0)) + size < size) {
-    failed_ = true;
     return NULL;
   }
 
   void* result = sbrk(size);
   if (result == reinterpret_cast<void*>(-1)) {
-    failed_ = true;
     return NULL;
   }
 
@@ -212,7 +244,6 @@
   // that we can find an aligned region within it.
   result = sbrk(size + alignment - 1);
   if (result == reinterpret_cast<void*>(-1)) {
-    failed_ = true;
     return NULL;
   }
   ptr = reinterpret_cast<uintptr_t>(result);
@@ -223,14 +254,9 @@
 #endif  // HAVE_SBRK
 }
 
-void SbrkSysAllocator::DumpStats(TCMalloc_Printer* printer) {
-  printer->printf("SbrkSysAllocator: failed_=%d\n", failed_);
-}
-
 void* MmapSysAllocator::Alloc(size_t size, size_t *actual_size,
                               size_t alignment) {
 #ifndef HAVE_MMAP
-  failed_ = true;
   return NULL;
 #else
   // Check if we should use mmap allocation.
@@ -273,7 +299,6 @@
                       MAP_PRIVATE|MAP_ANONYMOUS,
                       -1, 0);
   if (result == reinterpret_cast<void*>(MAP_FAILED)) {
-    failed_ = true;
     return NULL;
   }
 
@@ -297,14 +322,9 @@
 #endif  // HAVE_MMAP
 }
 
-void MmapSysAllocator::DumpStats(TCMalloc_Printer* printer) {
-  printer->printf("MmapSysAllocator: failed_=%d\n", failed_);
-}
-
 void* DevMemSysAllocator::Alloc(size_t size, size_t *actual_size,
                                 size_t alignment) {
 #ifndef HAVE_MMAP
-  failed_ = true;
   return NULL;
 #else
   static bool initialized = false;
@@ -325,7 +345,6 @@
   if (!initialized) {
     physmem_fd = open("/dev/mem", O_RDWR);
     if (physmem_fd < 0) {
-      failed_ = true;
       return NULL;
     }
     physmem_base = FLAGS_malloc_devmem_start*1024LL*1024LL;
@@ -357,7 +376,6 @@
   // check to see if we have any memory left
   if (physmem_limit != 0 &&
       ((size + extra) > (physmem_limit - physmem_base))) {
-    failed_ = true;
     return NULL;
   }
 
@@ -368,7 +386,6 @@
   void *result = mmap(0, size + extra, PROT_WRITE|PROT_READ,
                       MAP_SHARED, physmem_fd, physmem_base);
   if (result == reinterpret_cast<void*>(MAP_FAILED)) {
-    failed_ = true;
     return NULL;
   }
   uintptr_t ptr = reinterpret_cast<uintptr_t>(result);
@@ -394,15 +411,30 @@
 #endif  // HAVE_MMAP
 }
 
-void DevMemSysAllocator::DumpStats(TCMalloc_Printer* printer) {
-  printer->printf("DevMemSysAllocator: failed_=%d\n", failed_);
+void* DefaultSysAllocator::Alloc(size_t size, size_t *actual_size,
+                                 size_t alignment) {
+  for (int i = 0; i < kMaxAllocators; i++) {
+    if (!failed_[i] && allocs_[i] != NULL) {
+      void* result = allocs_[i]->Alloc(size, actual_size, alignment);
+      if (result != NULL) {
+        return result;
+      }
+      TCMalloc_MESSAGE(__FILE__, __LINE__, "%s failed.\n", names_[i]);
+      failed_[i] = true;
+    }
+  }
+  // After both failed, reset "failed_" to false so that a single failed
+  // allocation won't make the allocator never work again.
+  for (int i = 0; i < kMaxAllocators; i++) {
+    failed_[i] = false;
+  }
+  return NULL;
 }
 
 static bool system_alloc_inited = false;
 void InitSystemAllocators(void) {
-  // This determines the order in which system allocators are called
-  int i = kMaxDynamicAllocators;
-  allocators[i++] = new (devmem_space) DevMemSysAllocator();
+  MmapSysAllocator *mmap = new (mmap_space) MmapSysAllocator();
+  SbrkSysAllocator *sbrk = new (sbrk_space) SbrkSysAllocator();
 
   // In 64-bit debug mode, place the mmap allocator first since it
   // allocates pointers that do not fit in 32 bits and therefore gives
@@ -411,13 +443,15 @@
   // likely to look like pointers and therefore the conservative gc in
   // the heap-checker is less likely to misinterpret a number as a
   // pointer).
+  DefaultSysAllocator *sdef = new (default_space) DefaultSysAllocator();
   if (kDebugMode && sizeof(void*) > 4) {
-    allocators[i++] = new (mmap_space) MmapSysAllocator();
-    allocators[i++] = new (sbrk_space) SbrkSysAllocator();
+    sdef->SetChildAllocator(mmap, 0, mmap_name);
+    sdef->SetChildAllocator(sbrk, 1, sbrk_name);
   } else {
-    allocators[i++] = new (sbrk_space) SbrkSysAllocator();
-    allocators[i++] = new (mmap_space) MmapSysAllocator();
+    sdef->SetChildAllocator(sbrk, 0, sbrk_name);
+    sdef->SetChildAllocator(mmap, 1, mmap_name);
   }
+  sys_alloc = sdef;
 }
 
 void* TCMalloc_SystemAlloc(size_t size, size_t *actual_size,
@@ -435,26 +469,17 @@
   // Enforce minimum alignment
   if (alignment < sizeof(MemoryAligner)) alignment = sizeof(MemoryAligner);
 
-  // Try twice, once avoiding allocators that failed before, and once
-  // more trying all allocators even if they failed before.
-  for (int i = 0; i < 2; i++) {
-    for (int j = 0; j < kMaxAllocators; j++) {
-      SysAllocator *a = allocators[j];
-      if (a == NULL) continue;
-      if (a->usable_ && !a->failed_) {
-        void* result = a->Alloc(size, actual_size, alignment);
-        if (result != NULL) return result;
-      }
+  void* result = sys_alloc->Alloc(size, actual_size, alignment);
+  if (result != NULL) {
+    if (actual_size) {
+      CheckAddressBits<kAddressBits>(
+          reinterpret_cast<uintptr_t>(result) + *actual_size - 1);
+    } else {
+      CheckAddressBits<kAddressBits>(
+          reinterpret_cast<uintptr_t>(result) + size - 1);
     }
-
-    // nothing worked - reset failed_ flags and try again
-    for (int j = 0; j < kMaxAllocators; j++) {
-      SysAllocator *a = allocators[j];
-      if (a == NULL) continue;
-      a->failed_ = false;
-    }
   }
-  return NULL;
+  return result;
 }
 
 void TCMalloc_SystemRelease(void* start, size_t length) {
@@ -498,13 +523,3 @@
   // such that they need to be re-committed before they can be used by the
   // application.
 }
-
-void DumpSystemAllocatorStats(TCMalloc_Printer* printer) {
-  for (int j = 0; j < kMaxAllocators; j++) {
-    SysAllocator *a = allocators[j];
-    if (a == NULL) continue;
-    if (a->usable_) {
-      a->DumpStats(printer);
-    }
-  }
-}