Changeset 65311 in webkit for trunk/JavaScriptCore/wtf/StdLibExtras.h

Timestamp:

Aug 13, 2010, 3:14:36 AM (15 years ago)

Author:

[email protected]

Message:

Avoid increasing required alignment of target type warning on ARM
​https://bugs.webkit.org/show_bug.cgi?id=38045

Reviewed by Gavin Barraclough.

The reinterpret_cast<Type1*>([pointer to Type2]) expressions - where
sizeof(Type1) > sizeof(Type2) - cause the following warning on ARM:
increases required alignment of target type warnings.
Casting the type of [pointer to Type2] object to void* bypasses the
warning.

• JavaScriptCore/assembler/ARMAssembler.cpp:

(JSC::ARMAssembler::executableCopy):

• JavaScriptCore/assembler/AssemblerBuffer.h:

(JSC::AssemblerBuffer::putShortUnchecked):
(JSC::AssemblerBuffer::putIntUnchecked):
(JSC::AssemblerBuffer::putInt64Unchecked):

• JavaScriptCore/interpreter/RegisterFile.h:

(JSC::RegisterFile::RegisterFile):
(JSC::RegisterFile::grow):

• JavaScriptCore/jit/JITStubs.cpp:
• JavaScriptCore/pcre/pcre_compile.cpp:

(jsRegExpCompile):

• JavaScriptCore/runtime/JSArray.cpp:

(JSC::JSArray::putSlowCase):
(JSC::JSArray::increaseVectorLength):
(JSC::JSArray::increaseVectorPrefixLength):
(JSC::JSArray::shiftCount):
(JSC::JSArray::unshiftCount):

• JavaScriptCore/wtf/FastMalloc.cpp:

(WTF::PageHeapAllocator::New):
(WTF::TCMalloc_Central_FreeList::Populate):

• wtf/MD5.cpp:

(WTF::reverseBytes):
(WTF::MD5::addBytes):
(WTF::MD5::checksum):

• JavaScriptCore/wtf/StdLibExtras.h:

(isPointerTypeAlignmentOkay):
(reinterpret_cast_ptr):

• JavaScriptCore/wtf/Vector.h:

(WTF::VectorBuffer::inlineBuffer):

• JavaScriptCore/wtf/qt/StringQt.cpp:

(WTF::String::String):

File:

• trunk/JavaScriptCore/wtf/StdLibExtras.h (modified) (1 diff)

trunk/JavaScriptCore/wtf/StdLibExtras.h

@@ -52 +52 @@
 #define STRINGIZE_VALUE_OF(exp) STRINGIZE(exp)
 
+/*
+ * The reinterpret_cast<Type1*>([pointer to Type2]) expressions - where
+ * sizeof(Type1) > sizeof(Type2) - cause the following warning on ARM with GCC:
+ * increases required alignment of target type.
+ *
+ * An implicit or an extra static_cast<void*> bypasses the warning.
+ * For more info see the following bugzilla entries:
+ * - https://bugs.webkit.org/show_bug.cgi?id=38045
+ * - http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43976
+ */
+#if CPU(ARM) && COMPILER(GCC)
+template<typename Type>
+bool isPointerTypeAlignmentOkay(Type* ptr)
+{
+    return !(reinterpret_cast<intptr_t>(ptr) % __alignof__(Type));
+}
+
+template<typename TypePtr>
+TypePtr reinterpret_cast_ptr(void* ptr)
+{
+    ASSERT(isPointerTypeAlignmentOkay(reinterpret_cast<TypePtr>(ptr)));
+    return reinterpret_cast<TypePtr>(ptr);
+}
+
+template<typename TypePtr>
+TypePtr reinterpret_cast_ptr(const void* ptr)
+{
+    ASSERT(isPointerTypeAlignmentOkay(reinterpret_cast<TypePtr>(ptr)));
+    return reinterpret_cast<TypePtr>(ptr);
+}
+#else
+#define reinterpret_cast_ptr reinterpret_cast
+#endif
+
 namespace WTF {