Handle zero-size allocations properly in heap profiler

base/trace_event/heap_profiler_allocation_register_unittest.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/trace_event/heap_profiler_allocation_register.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/process/process_metrics.h"
@@ skipping 37 matching lines @@
 // the sizes of the entries.
 size_t SumAllSizes(const AllocationRegister& reg) {
   size_t sum = 0;
 
   for (auto i : reg)
     sum += i.size;
 
   return sum;
 }
 
+TEST_F(AllocationRegisterTest, NoZeroSizeInsert) {
+  AllocationRegister reg;
+  AllocationContext ctx = AllocationContext::Empty();
+
+  reg.Insert(reinterpret_cast<void*>(1), 0, ctx);

[Primiano Tucci (use gerrit), 2016/04/06 08:20:44]

I think this (and line 64) can be moved to the InsertRemove test below. IMHO not
worth making that a dedicated TEST_F.
Just add a comment before saying
// Zero-sized allocations should be discarded.

+
+  EXPECT_EQ(0u, OrAllAddresses(reg));
+}
+
 TEST_F(AllocationRegisterTest, InsertRemove) {
   AllocationRegister reg;
   AllocationContext ctx = AllocationContext::Empty();
 
   EXPECT_EQ(0u, OrAllAddresses(reg));
 
-  reg.Insert(reinterpret_cast<void*>(1), 0, ctx);
+  reg.Insert(reinterpret_cast<void*>(1), 1, ctx);
 
   EXPECT_EQ(1u, OrAllAddresses(reg));
 
-  reg.Insert(reinterpret_cast<void*>(2), 0, ctx);
+  reg.Insert(reinterpret_cast<void*>(2), 1, ctx);
 
   EXPECT_EQ(3u, OrAllAddresses(reg));
 
-  reg.Insert(reinterpret_cast<void*>(4), 0, ctx);
+  reg.Insert(reinterpret_cast<void*>(4), 1, ctx);
 
   EXPECT_EQ(7u, OrAllAddresses(reg));
 
   reg.Remove(reinterpret_cast<void*>(2));
 
   EXPECT_EQ(5u, OrAllAddresses(reg));
 
   reg.Remove(reinterpret_cast<void*>(4));
 
   EXPECT_EQ(1u, OrAllAddresses(reg));
 
   reg.Remove(reinterpret_cast<void*>(1));
 
   EXPECT_EQ(0u, OrAllAddresses(reg));
 }
 
 TEST_F(AllocationRegisterTest, DoubleFreeIsAllowed) {
   AllocationRegister reg;
   AllocationContext ctx = AllocationContext::Empty();
 
-  reg.Insert(reinterpret_cast<void*>(1), 0, ctx);
-  reg.Insert(reinterpret_cast<void*>(2), 0, ctx);
+  reg.Insert(reinterpret_cast<void*>(1), 1, ctx);
+  reg.Insert(reinterpret_cast<void*>(2), 1, ctx);
   reg.Remove(reinterpret_cast<void*>(1));
   reg.Remove(reinterpret_cast<void*>(1));  // Remove for the second time.
   reg.Remove(reinterpret_cast<void*>(4));  // Remove never inserted address.
 
   EXPECT_EQ(2u, OrAllAddresses(reg));
 }
 
 TEST_F(AllocationRegisterTest, DoubleInsertOverwrites) {
   // TODO(ruuda): Although double insert happens in practice, it should not.
   // Find out the cause and ban double insert if possible.
@@ skipping 67 matching lines @@
 TEST_F(AllocationRegisterTest, InsertRemoveRandomOrder) {
   size_t expected_sum = 0;
   AllocationRegister reg;
   AllocationContext ctx = AllocationContext::Empty();
 
   uintptr_t generator = 3;
   uintptr_t prime = 1013;
   uint32_t initial_water_mark = GetHighWaterMark(reg);
 
   for (uintptr_t i = 2; i < prime; i++) {
-    size_t size = i % 31;
+    size_t size = i % 31 + 1;
     expected_sum += size;
     reg.Insert(reinterpret_cast<void*>(i), size, ctx);
   }
 
   // This should have used a fresh slot for each of the |prime - 2| inserts.
   ASSERT_EQ(prime - 2, GetHighWaterMark(reg) - initial_water_mark);
 
   // Iterate the numbers 2, 3, ..., prime - 1 in pseudorandom order.
   for (uintptr_t i = generator; i != 1; i = (i * generator) % prime) {
-    size_t size = i % 31;
+    size_t size = i % 31 + 1;
     expected_sum -= size;
     reg.Remove(reinterpret_cast<void*>(i));
     EXPECT_EQ(expected_sum, SumAllSizes(reg));
   }
 
   ASSERT_EQ(0u, expected_sum);
 
   // Insert |prime - 2| entries again. This should use cells from the free list,
   // so the |next_unused_cell_| index should not change.
   for (uintptr_t i = 2; i < prime; i++)
-    reg.Insert(reinterpret_cast<void*>(i), 0, ctx);
+    reg.Insert(reinterpret_cast<void*>(i), 1, ctx);
 
   ASSERT_EQ(prime - 2, GetHighWaterMark(reg) - initial_water_mark);
 
   // Inserting one more entry should use a fresh cell again.
-  reg.Insert(reinterpret_cast<void*>(prime), 0, ctx);
+  reg.Insert(reinterpret_cast<void*>(prime), 1, ctx);
   ASSERT_EQ(prime - 1, GetHighWaterMark(reg) - initial_water_mark);
 }
 
 TEST_F(AllocationRegisterTest, ChangeContextAfterInsertion) {
   using Allocation = AllocationRegister::Allocation;
   const char kStdString[] = "std::string";
   AllocationRegister reg;
   AllocationContext ctx = AllocationContext::Empty();
 
   reg.Insert(reinterpret_cast<void*>(17), 1, ctx);
@@ skipping 42 matching lines @@
 TEST_F(AllocationRegisterTest, OverflowDeathTest) {
   // Use a smaller register to prevent OOM errors on low-end devices.
   AllocationRegister reg(static_cast<uint32_t>(GetNumCellsPerPage()));
   AllocationContext ctx = AllocationContext::Empty();
   uintptr_t i;
 
   // Fill up all of the memory allocated for the register. |GetNumCells(reg)|
   // minus 1 elements are inserted, because cell 0 is unused, so this should
   // fill up the available cells exactly.
   for (i = 1; i < GetNumCells(reg); i++) {
-    reg.Insert(reinterpret_cast<void*>(i), 0, ctx);
+    reg.Insert(reinterpret_cast<void*>(i), 1, ctx);
   }
 
   // Adding just one extra element might still work because the allocated memory
   // is rounded up to the page size. Adding a page full of elements should cause
   // overflow.
   const size_t cells_per_page = GetNumCellsPerPage();
 
   ASSERT_DEATH(for (size_t j = 0; j < cells_per_page; j++) {
-    reg.Insert(reinterpret_cast<void*>(i + j), 0, ctx);
+    reg.Insert(reinterpret_cast<void*>(i + j), 1, ctx);
   }, "");
 }
 #endif
 
 }  // namespace trace_event
 }  // namespace base