Merge pull request #714 from trav90/class-memaccess-errors

Fix more -Wclass-memaccess warnings:

- Avoid using memset on a not-trivial types
- Avoid doing memset on non-POD structures
- Be more restrictive with memset on Array containers

4 files changed, 56 insertions, 17 deletions

diff --git a/dom/bindings/BindingUtils.h b/dom/bindings/BindingUtils.h
index 3e58390c9..24b47a545 100644
--- a/dom/bindings/BindingUtils.h
+++ b/dom/bindings/BindingUtils.h
@@ -515,7 +515,7 @@ class ProtoAndIfaceCache
   {
   public:
     PageTableCache() {
-      memset(&mPages, 0, sizeof(mPages));
+      memset(mPages.begin(), 0, sizeof(mPages));
     }
 
     ~PageTableCache() {
diff --git a/js/public/HashTable.h b/js/public/HashTable.h
index 5d4c0665d..8a2493b55 100644
--- a/js/public/HashTable.h
+++ b/js/public/HashTable.h
@@ -12,6 +12,7 @@
 #include "mozilla/Attributes.h"
 #include "mozilla/Casting.h"
 #include "mozilla/HashFunctions.h"
+#include "mozilla/MemoryChecking.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/Move.h"
 #include "mozilla/Opaque.h"
@@ -805,17 +806,22 @@ class HashTableEntry
     void operator=(const HashTableEntry&) = delete;
     ~HashTableEntry() = delete;
 
+    void destroyStoredT() {
+        mem.addr()->~T();
+        MOZ_MAKE_MEM_UNDEFINED(mem.addr(), sizeof(*mem.addr()));
+    }
+
   public:
     // NB: HashTableEntry is treated as a POD: no constructor or destructor calls.
 
     void destroyIfLive() {
         if (isLive())
-            mem.addr()->~T();
+            destroyStoredT();
     }
 
     void destroy() {
         MOZ_ASSERT(isLive());
-        mem.addr()->~T();
+        destroyStoredT();
     }
 
     void swap(HashTableEntry* other) {
@@ -835,10 +841,28 @@ class HashTableEntry
     NonConstT& getMutable() { MOZ_ASSERT(isLive()); return *mem.addr(); }
 
     bool isFree() const    { return keyHash == sFreeKey; }
-    void clearLive()       { MOZ_ASSERT(isLive()); keyHash = sFreeKey; mem.addr()->~T(); }
-    void clear()           { if (isLive()) mem.addr()->~T(); keyHash = sFreeKey; }
+    void clearLive() {
+        MOZ_ASSERT(isLive());
+        keyHash = sFreeKey;
+        destroyStoredT();
+    }
+
+    void clear() {
+        if (isLive())
+            destroyStoredT();
+
+        MOZ_MAKE_MEM_UNDEFINED(this, sizeof(*this));
+        keyHash = sFreeKey;
+    }
+
     bool isRemoved() const { return keyHash == sRemovedKey; }
-    void removeLive()      { MOZ_ASSERT(isLive()); keyHash = sRemovedKey; mem.addr()->~T(); }
+
+    void removeLive() {
+        MOZ_ASSERT(isLive());
+        keyHash = sRemovedKey;
+        destroyStoredT();
+    }
+
     bool isLive() const    { return isLiveHash(keyHash); }
     void setCollision()               { MOZ_ASSERT(isLive()); keyHash |= sCollisionBit; }
     void unsetCollision()             { keyHash &= ~sCollisionBit; }
@@ -1654,14 +1678,10 @@ class HashTable : private AllocPolicy
   public:
     void clear()
     {
-        if (mozilla::IsPod<Entry>::value) {
-            memset(table, 0, sizeof(*table) * capacity());
-        } else {
-            uint32_t tableCapacity = capacity();
-            Entry* end = table + tableCapacity;
-            for (Entry* e = table; e < end; ++e)
-                e->clear();
-        }
+        Entry* end = table + capacity();
+        for (Entry* e = table; e < end; ++e)
+            e->clear();
+
         removedCount = 0;
         entryCount = 0;
 #ifdef JS_DEBUG
diff --git a/js/public/MemoryMetrics.h b/js/public/MemoryMetrics.h
index 9b5caa24b..b0b26631c 100644
--- a/js/public/MemoryMetrics.h
+++ b/js/public/MemoryMetrics.h
@@ -37,7 +37,13 @@ struct TabSizes
         Other
     };
 
-    TabSizes() { mozilla::PodZero(this); }
+    TabSizes()
+      : objects(0)
+      , strings(0)
+      , private_(0)
+      , other(0)
+    {
+    }
 
     void add(Kind kind, size_t n) {
         switch (kind) {
@@ -68,7 +74,15 @@ struct ServoSizes
         Ignore
     };
 
-    ServoSizes() { mozilla::PodZero(this); }
+    ServoSizes()
+      : gcHeapUsed(0)
+      , gcHeapUnused(0)
+      , gcHeapAdmin(0)
+      , gcHeapDecommitted(0)
+      , mallocHeap(0)
+      , nonHeap(0)
+    {
+    }
 
     void add(Kind kind, size_t n) {
         switch (kind) {
diff --git a/layout/base/nsArenaMemoryStats.h b/layout/base/nsArenaMemoryStats.h
index ba09baaa4..2a872cfe8 100644
--- a/layout/base/nsArenaMemoryStats.h
+++ b/layout/base/nsArenaMemoryStats.h
@@ -18,7 +18,12 @@ public:
       Other       // Everything else.
   };
 
-  nsTabSizes() { mozilla::PodZero(this); }
+  nsTabSizes()
+    : mDom(0)
+    , mStyle(0)
+    , mOther(0)
+  {
+  }
 
   void add(Kind kind, size_t n)
   {