Reviewers: Erik Corry,
Description:
Switch from template functions overloading to partial template
specialization.
This should fix compilation on old GCC.
Please review this at http://codereview.chromium.org/6350012/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files:
M src/utils.h
Index: src/utils.h
diff --git a/src/utils.h b/src/utils.h
index
21e70d758e9df8e980fc439dbcafc3910e984f82..219343b7fab0fe096c35aae938c781c3f034ff51
100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -760,20 +760,32 @@ static inline int TenToThe(int exponent) {
// you can use BitCast to cast one pointer type to another. This confuses
gcc
// enough that it can no longer see that you have cast one pointer type to
// another thus avoiding the warning.
+
+// We need different implementations of BitCast for pointer and non-pointer
+// values. We use partial specialization of auxiliary struct to work around
+// issues with template functions overloading.
template <class Dest, class Source>
-inline Dest BitCast(const Source& source) {
- // Compile time assertion: sizeof(Dest) == sizeof(Source)
- // A compile error here means your Dest and Source have different sizes.
- typedef char VerifySizesAreEqual[sizeof(Dest) == sizeof(Source) ? 1 :
-1];
+struct BitCastHelper {
+ STATIC_ASSERT(sizeof(Dest) == sizeof(Source));
- Dest dest;
- memcpy(&dest, &source, sizeof(dest));
- return dest;
-}
+ INLINE(static Dest cast(const Source& source)) {
+ Dest dest;
+ memcpy(&dest, &source, sizeof(dest));
+ return dest;
+ }
+};
template <class Dest, class Source>
-inline Dest BitCast(Source* source) {
- return BitCast<Dest>(reinterpret_cast<uintptr_t>(source));
+struct BitCastHelper<Dest, Source*> {
+ INLINE(static Dest cast(Source* source)) {
+ return BitCastHelper<Dest, uintptr_t>::
+ cast(reinterpret_cast<uintptr_t>(source));
+ }
+};
+
+template <class Dest, class Source>
+inline Dest BitCast(const Source& source) {
+ return BitCastHelper<Dest, Source>::cast(source);
}
} } // namespace v8::internal
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