#include "include/v8.h"
#include "src/allocation.h"
+#include "src/base/bits.h"
#include "src/base/logging.h"
#include "src/base/macros.h"
#include "src/base/platform/platform.h"
// ----------------------------------------------------------------------------
// General helper functions
+
+// Same as strcmp, but can handle NULL arguments.
+inline bool CStringEquals(const char* s1, const char* s2) {
+ return (s1 == s2) || (s1 != NULL && s2 != NULL && strcmp(s1, s2) == 0);
+}
+
+
// X must be a power of 2. Returns the number of trailing zeros.
inline int WhichPowerOf2(uint32_t x) {
- DCHECK(IsPowerOf2(x));
+ DCHECK(base::bits::IsPowerOfTwo32(x));
int bits = 0;
#ifdef DEBUG
int original_x = x;
}
+template <typename T, typename U>
+inline bool IsAligned(T value, U alignment) {
+ return (value & (alignment - 1)) == 0;
+}
+
+
// Returns true if (addr + offset) is aligned.
inline bool IsAddressAligned(Address addr,
intptr_t alignment,
};
-// Compare ASCII/16bit chars to ASCII/16bit chars.
+// Compare 8bit/16bit chars to 8bit/16bit chars.
template <typename lchar, typename rchar>
inline int CompareCharsUnsigned(const lchar* lhs,
const rchar* rhs,
int chars) {
const lchar* limit = lhs + chars;
-#ifdef V8_HOST_CAN_READ_UNALIGNED
- if (sizeof(*lhs) == sizeof(*rhs)) {
- // Number of characters in a uintptr_t.
- static const int kStepSize = sizeof(uintptr_t) / sizeof(*lhs); // NOLINT
- while (lhs <= limit - kStepSize) {
- if (*reinterpret_cast<const uintptr_t*>(lhs) !=
- *reinterpret_cast<const uintptr_t*>(rhs)) {
- break;
- }
- lhs += kStepSize;
- rhs += kStepSize;
- }
+ if (sizeof(*lhs) == sizeof(char) && sizeof(*rhs) == sizeof(char)) {
+ // memcmp compares byte-by-byte, yielding wrong results for two-byte
+ // strings on little-endian systems.
+ return memcmp(lhs, rhs, chars);
}
-#endif
while (lhs < limit) {
int r = static_cast<int>(*lhs) - static_cast<int>(*rhs);
if (r != 0) return r;
}
-// The type-based aliasing rule allows the compiler to assume that pointers of
-// different types (for some definition of different) never alias each other.
-// Thus the following code does not work:
-//
-// float f = foo();
-// int fbits = *(int*)(&f);
-//
-// The compiler 'knows' that the int pointer can't refer to f since the types
-// don't match, so the compiler may cache f in a register, leaving random data
-// in fbits. Using C++ style casts makes no difference, however a pointer to
-// char data is assumed to alias any other pointer. This is the 'memcpy
-// exception'.
-//
-// Bit_cast uses the memcpy exception to move the bits from a variable of one
-// type of a variable of another type. Of course the end result is likely to
-// be implementation dependent. Most compilers (gcc-4.2 and MSVC 2005)
-// will completely optimize BitCast away.
-//
-// There is an additional use for BitCast.
-// Recent gccs will warn when they see casts that may result in breakage due to
-// the type-based aliasing rule. If you have checked that there is no breakage
-// 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>
-struct BitCastHelper {
- STATIC_ASSERT(sizeof(Dest) == sizeof(Source));
-
- INLINE(static Dest cast(const Source& source)) {
- Dest dest;
- memcpy(&dest, &source, sizeof(dest));
- return dest;
- }
-};
-
-template <class Dest, class 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));
-
-template <class Dest, class Source>
-inline Dest BitCast(const Source& source) {
- return BitCastHelper<Dest, Source>::cast(source);
-}
-
-
template<typename ElementType, int NumElements>
class EmbeddedContainer {
public:
}
-// Simple wrapper that allows an ExternalString to refer to a
-// Vector<const char>. Doesn't assume ownership of the data.
-class AsciiStringAdapter: public v8::String::ExternalAsciiStringResource {
- public:
- explicit AsciiStringAdapter(Vector<const char> data) : data_(data) {}
-
- virtual const char* data() const { return data_.start(); }
-
- virtual size_t length() const { return data_.length(); }
-
- private:
- Vector<const char> data_;
-};
-
-
// Simple support to read a file into a 0-terminated C-string.
// The returned buffer must be freed by the caller.
// On return, *exits tells whether the file existed.
INLINE(void CopyCharsUnsigned(uint16_t* dest, const uint16_t* src, int chars));
#endif
-// Copy from ASCII/16bit chars to ASCII/16bit chars.
+// Copy from 8bit/16bit chars to 8bit/16bit chars.
template <typename sourcechar, typename sinkchar>
INLINE(void CopyChars(sinkchar* dest, const sourcechar* src, int chars));
template <typename sourcechar, typename sinkchar>
void CopyCharsUnsigned(sinkchar* dest, const sourcechar* src, int chars) {
sinkchar* limit = dest + chars;
-#ifdef V8_HOST_CAN_READ_UNALIGNED
- if (sizeof(*dest) == sizeof(*src)) {
- if (chars >= static_cast<int>(kMinComplexMemCopy / sizeof(*dest))) {
- MemCopy(dest, src, chars * sizeof(*dest));
- return;
- }
- // Number of characters in a uintptr_t.
- static const int kStepSize = sizeof(uintptr_t) / sizeof(*dest); // NOLINT
- DCHECK(dest + kStepSize > dest); // Check for overflow.
- while (dest + kStepSize <= limit) {
- *reinterpret_cast<uintptr_t*>(dest) =
- *reinterpret_cast<const uintptr_t*>(src);
- dest += kStepSize;
- src += kStepSize;
- }
- }
-#endif
- while (dest < limit) {
- *dest++ = static_cast<sinkchar>(*src++);
+ if ((sizeof(*dest) == sizeof(*src)) &&
+ (chars >= static_cast<int>(kMinComplexMemCopy / sizeof(*dest)))) {
+ MemCopy(dest, src, chars * sizeof(*dest));
+ } else {
+ while (dest < limit) *dest++ = static_cast<sinkchar>(*src++);
}
}
}
-} } // namespace v8::internal
+// Returns current value of top of the stack. Works correctly with ASAN.
+DISABLE_ASAN
+inline uintptr_t GetCurrentStackPosition() {
+ // Takes the address of the limit variable in order to find out where
+ // the top of stack is right now.
+ uintptr_t limit = reinterpret_cast<uintptr_t>(&limit);
+ return limit;
+}
+
+} // namespace internal
+} // namespace v8
#endif // V8_UTILS_H_
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