Change the code to avoid three unit test failures on release build

core/fxcrt/fx_basic_memmgr_unittest.cpp

 // Copyright 2015 PDFium 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 <limits>
 
 #include "core/fxcrt/include/fx_memory.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
@@ skipping 11 matching lines @@
 TEST(fxcrt, DISABLED_FX_AllocOOM) {
   EXPECT_DEATH_IF_SUPPORTED((void)FX_Alloc(int, kMaxIntAlloc), "");
 
   int* ptr = FX_Alloc(int, 1);
   EXPECT_TRUE(ptr);
   EXPECT_DEATH_IF_SUPPORTED((void)FX_Realloc(int, ptr, kMaxIntAlloc), "");
   FX_Free(ptr);
 }
 
 TEST(fxcrt, FX_AllocOverflow) {
-  EXPECT_DEATH_IF_SUPPORTED((void)FX_Alloc(int, kOverflowIntAlloc), "");
+  // |ptr| needs to be defined and used to avoid Clang optimizes away the
+  // FX_Alloc() statement overzealously for optimized builds.
+  int* ptr = nullptr;
+  EXPECT_DEATH_IF_SUPPORTED(ptr = FX_Alloc(int, kOverflowIntAlloc), "") << ptr;
 
-  int* ptr = FX_Alloc(int, 1);
+  ptr = FX_Alloc(int, 1);
   EXPECT_TRUE(ptr);
   EXPECT_DEATH_IF_SUPPORTED((void)FX_Realloc(int, ptr, kOverflowIntAlloc), "");
   FX_Free(ptr);
 }
 
 TEST(fxcrt, FX_AllocOverflow2D) {
-  EXPECT_DEATH_IF_SUPPORTED((void)FX_Alloc2D(int, kWidth, kOverflowIntAlloc2D),
-                            "");
+  // |ptr| needs to be defined and used to avoid Clang optimizes away the
+  // FX_Alloc() statement overzealously for optimized builds.
+  int* ptr = nullptr;
+  EXPECT_DEATH_IF_SUPPORTED(ptr = FX_Alloc2D(int, kWidth, kOverflowIntAlloc2D),
+                            "")
+      << ptr;
 }
 
 TEST(fxcrt, DISABLED_FX_TryAllocOOM) {
   EXPECT_FALSE(FX_TryAlloc(int, kMaxIntAlloc));
 
   int* ptr = FX_Alloc(int, 1);
   EXPECT_TRUE(ptr);
   EXPECT_FALSE(FX_TryRealloc(int, ptr, kMaxIntAlloc));
   FX_Free(ptr);
 }
 
 TEST(fxcrt, FX_TryAllocOverflow) {
-  EXPECT_FALSE(FX_TryAlloc(int, kOverflowIntAlloc));
+  // |ptr| needs to be defined and used to avoid Clang optimizes away the
+  // calloc() statement overzealously for optimized builds.
+  int* ptr = (int*)calloc(sizeof(int), kOverflowIntAlloc);
+  EXPECT_FALSE(ptr) << ptr;
 
-  int* ptr = FX_Alloc(int, 1);
+  ptr = FX_Alloc(int, 1);
   EXPECT_TRUE(ptr);
   EXPECT_FALSE(FX_TryRealloc(int, ptr, kOverflowIntAlloc));
   FX_Free(ptr);
 }
 
 TEST(fxcrt, DISABLED_FXMEM_DefaultOOM) {
   EXPECT_FALSE(FXMEM_DefaultAlloc(kMaxByteAlloc, 0));
 
   void* ptr = FXMEM_DefaultAlloc(1, 0);
   EXPECT_TRUE(ptr);
   EXPECT_FALSE(FXMEM_DefaultRealloc(ptr, kMaxByteAlloc, 0));
   FXMEM_DefaultFree(ptr, 0);
 }