Skip to content

V
V8
Commit 11aaf0fb authored by Igor Sheludko's avatar Igor Sheludko Committed by Commit Bot
Browse files
Options

[api] Move tagging scheme definition up in include/v8.h 

... in order to be able to use it in other constants definitions in the header.

Bug: v8:7570
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: Id5d6ae34ab401ecf063bf5897b87b6bb87c24960
Reviewed-on: https://chromium-review.googlesource.com/1032782Reviewed-by: 's avatarYang Guo <yangguo@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53097}
parent 9d5aea8d
Hide whitespace changes
Inline Side-by-side
Showing with 100 additions and 97 deletions
include/v8.h
View file @ 11aaf0fb
......@@ -156,6 +156,95 @@ class GlobalHandles;
namespace wasm {
class StreamingDecoder;
} // namespace wasm
/**
* Configuration of tagging scheme.
*/
const int kApiPointerSize = sizeof(void*); // NOLINT
const int kApiDoubleSize = sizeof(double); // NOLINT
const int kApiIntSize = sizeof(int); // NOLINT
const int kApiInt64Size = sizeof(int64_t); // NOLINT
// Tag information for HeapObject.
const int kHeapObjectTag = 1;
const int kWeakHeapObjectTag = 3;
const int kHeapObjectTagSize = 2;
const intptr_t kHeapObjectTagMask = (1 << kHeapObjectTagSize) - 1;
// Tag information for Smi.
const int kSmiTag = 0;
const int kSmiTagSize = 1;
const intptr_t kSmiTagMask = (1 << kSmiTagSize) - 1;
template <size_t ptr_size>
struct SmiTagging;
template <int kSmiShiftSize>
V8_INLINE internal::Object* IntToSmi(int value) {
int smi_shift_bits = kSmiTagSize + kSmiShiftSize;
uintptr_t tagged_value =
(static_cast<uintptr_t>(value) << smi_shift_bits) | kSmiTag;
return reinterpret_cast<internal::Object*>(tagged_value);
}
// Smi constants for 32-bit systems.
template <>
struct SmiTagging<4> {
enum { kSmiShiftSize = 0, kSmiValueSize = 31 };
static int SmiShiftSize() { return kSmiShiftSize; }
static int SmiValueSize() { return kSmiValueSize; }
V8_INLINE static int SmiToInt(const internal::Object* value) {
int shift_bits = kSmiTagSize + kSmiShiftSize;
// Throw away top 32 bits and shift down (requires >> to be sign extending).
return static_cast<int>(reinterpret_cast<intptr_t>(value)) >> shift_bits;
}
V8_INLINE static internal::Object* IntToSmi(int value) {
return internal::IntToSmi<kSmiShiftSize>(value);
}
V8_INLINE static bool IsValidSmi(intptr_t value) {
// To be representable as an tagged small integer, the two
// most-significant bits of 'value' must be either 00 or 11 due to
// sign-extension. To check this we add 01 to the two
// most-significant bits, and check if the most-significant bit is 0
//
// CAUTION: The original code below:
// bool result = ((value + 0x40000000) & 0x80000000) == 0;
// may lead to incorrect results according to the C language spec, and
// in fact doesn't work correctly with gcc4.1.1 in some cases: The
// compiler may produce undefined results in case of signed integer
// overflow. The computation must be done w/ unsigned ints.
return static_cast<uintptr_t>(value) + 0x40000000U < 0x80000000U;
}
};
// Smi constants for 64-bit systems.
template <>
struct SmiTagging<8> {
enum { kSmiShiftSize = 31, kSmiValueSize = 32 };
static int SmiShiftSize() { return kSmiShiftSize; }
static int SmiValueSize() { return kSmiValueSize; }
V8_INLINE static int SmiToInt(const internal::Object* value) {
int shift_bits = kSmiTagSize + kSmiShiftSize;
// Shift down and throw away top 32 bits.
return static_cast<int>(reinterpret_cast<intptr_t>(value) >> shift_bits);
}
V8_INLINE static internal::Object* IntToSmi(int value) {
return internal::IntToSmi<kSmiShiftSize>(value);
}
V8_INLINE static bool IsValidSmi(intptr_t value) {
// To be representable as a long smi, the value must be a 32-bit integer.
return (value == static_cast<int32_t>(value));
}
};
typedef SmiTagging<kApiPointerSize> PlatformSmiTagging;
const int kSmiShiftSize = PlatformSmiTagging::kSmiShiftSize;
const int kSmiValueSize = PlatformSmiTagging::kSmiValueSize;
const int kSmiMinValue = (static_cast<unsigned int>(-1)) << (kSmiValueSize - 1);
const int kSmiMaxValue = -(kSmiMinValue + 1);
constexpr bool SmiValuesAre31Bits() { return kSmiValueSize == 31; }
constexpr bool SmiValuesAre32Bits() { return kSmiValueSize == 32; }
} // namespace internal
namespace debug {
......@@ -2546,8 +2635,9 @@ enum class NewStringType {
*/
class V8_EXPORT String : public Name {
public:
static constexpr int kMaxLength =
sizeof(void*) == 4 ? (1 << 28) - 16 : (1 << 30) - 1 - 24;
static constexpr int kMaxLength = internal::kApiPointerSize == 4
? (1 << 28) - 16
: internal::kSmiMaxValue / 2 - 24;
enum Encoding {
UNKNOWN_ENCODING = 0x1,
......@@ -4544,8 +4634,7 @@ class V8_EXPORT TypedArray : public ArrayBufferView {
/*
* The largest typed array size that can be constructed using New.
*/
static constexpr size_t kMaxLength =
sizeof(void*) == 4 ? (1u << 30) - 1 : (1u << 31) - 1;
static constexpr size_t kMaxLength = internal::kSmiMaxValue;
/**
* Number of elements in this typed array
......@@ -9010,85 +9099,6 @@ class V8_EXPORT Locker {
namespace internal {
const int kApiPointerSize = sizeof(void*); // NOLINT
const int kApiIntSize = sizeof(int); // NOLINT
const int kApiInt64Size = sizeof(int64_t); // NOLINT
// Tag information for HeapObject.
const int kHeapObjectTag = 1;
const int kWeakHeapObjectTag = 3;
const int kHeapObjectTagSize = 2;
const intptr_t kHeapObjectTagMask = (1 << kHeapObjectTagSize) - 1;
// Tag information for Smi.
const int kSmiTag = 0;
const int kSmiTagSize = 1;
const intptr_t kSmiTagMask = (1 << kSmiTagSize) - 1;
template <size_t ptr_size> struct SmiTagging;
template<int kSmiShiftSize>
V8_INLINE internal::Object* IntToSmi(int value) {
int smi_shift_bits = kSmiTagSize + kSmiShiftSize;
uintptr_t tagged_value =
(static_cast<uintptr_t>(value) << smi_shift_bits) | kSmiTag;
return reinterpret_cast<internal::Object*>(tagged_value);
}
// Smi constants for 32-bit systems.
template <> struct SmiTagging<4> {
enum { kSmiShiftSize = 0, kSmiValueSize = 31 };
static int SmiShiftSize() { return kSmiShiftSize; }
static int SmiValueSize() { return kSmiValueSize; }
V8_INLINE static int SmiToInt(const internal::Object* value) {
int shift_bits = kSmiTagSize + kSmiShiftSize;
// Throw away top 32 bits and shift down (requires >> to be sign extending).
return static_cast<int>(reinterpret_cast<intptr_t>(value)) >> shift_bits;
}
V8_INLINE static internal::Object* IntToSmi(int value) {
return internal::IntToSmi<kSmiShiftSize>(value);
}
V8_INLINE static bool IsValidSmi(intptr_t value) {
// To be representable as an tagged small integer, the two
// most-significant bits of 'value' must be either 00 or 11 due to
// sign-extension. To check this we add 01 to the two
// most-significant bits, and check if the most-significant bit is 0
//
// CAUTION: The original code below:
// bool result = ((value + 0x40000000) & 0x80000000) == 0;
// may lead to incorrect results according to the C language spec, and
// in fact doesn't work correctly with gcc4.1.1 in some cases: The
// compiler may produce undefined results in case of signed integer
// overflow. The computation must be done w/ unsigned ints.
return static_cast<uintptr_t>(value) + 0x40000000U < 0x80000000U;
}
};
// Smi constants for 64-bit systems.
template <> struct SmiTagging<8> {
enum { kSmiShiftSize = 31, kSmiValueSize = 32 };
static int SmiShiftSize() { return kSmiShiftSize; }
static int SmiValueSize() { return kSmiValueSize; }
V8_INLINE static int SmiToInt(const internal::Object* value) {
int shift_bits = kSmiTagSize + kSmiShiftSize;
// Shift down and throw away top 32 bits.
return static_cast<int>(reinterpret_cast<intptr_t>(value) >> shift_bits);
}
V8_INLINE static internal::Object* IntToSmi(int value) {
return internal::IntToSmi<kSmiShiftSize>(value);
}
V8_INLINE static bool IsValidSmi(intptr_t value) {
// To be representable as a long smi, the value must be a 32-bit integer.
return (value == static_cast<int32_t>(value));
}
};
typedef SmiTagging<kApiPointerSize> PlatformSmiTagging;
const int kSmiShiftSize = PlatformSmiTagging::kSmiShiftSize;
const int kSmiValueSize = PlatformSmiTagging::kSmiValueSize;
V8_INLINE static bool SmiValuesAre31Bits() { return kSmiValueSize == 31; }
V8_INLINE static bool SmiValuesAre32Bits() { return kSmiValueSize == 32; }
/**
* This class exports constants and functionality from within v8 that
* is necessary to implement inline functions in the v8 api. Don't
......@@ -9102,7 +9112,7 @@ class Internals {
static const int kMapInstanceTypeOffset = 1 * kApiPointerSize + kApiIntSize;
static const int kStringResourceOffset = 3 * kApiPointerSize;
static const int kOddballKindOffset = 4 * kApiPointerSize + sizeof(double);
static const int kOddballKindOffset = 4 * kApiPointerSize + kApiDoubleSize;
static const int kForeignAddressOffset = kApiPointerSize;
static const int kJSObjectHeaderSize = 3 * kApiPointerSize;
static const int kFixedArrayHeaderSize = 2 * kApiPointerSize;
......
src/objects.h
View file @ 11aaf0fb
......@@ -1645,9 +1645,8 @@ class Smi: public Object {
DECL_VERIFIER(Smi)
static constexpr Smi* const kZero = nullptr;
static const int kMinValue =
(static_cast<unsigned int>(-1)) << (kSmiValueSize - 1);
static const int kMaxValue = -(kMinValue + 1);
static const int kMinValue = kSmiMinValue;
static const int kMaxValue = kSmiMaxValue;
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(Smi);
......
src/objects/string.h
View file @ 11aaf0fb
......@@ -355,6 +355,8 @@ class String : public Name {
// See include/v8.h for the definition.
static const int kMaxLength = v8::String::kMaxLength;
static_assert(kMaxLength <= (Smi::kMaxValue / 2 - kSize),
"Unexpected max String length");
// Max length for computing hash. For strings longer than this limit the
// string length is used as the hash value.
......
test/mjsunit/compiler/string-concat-deopt.js
View file @ 11aaf0fb
......@@ -44,11 +44,7 @@
assertEquals("abcde", f("de"));
assertEquals("abcde", f("de"));
%OptimizeFunctionOnNextCall(f);
var s = "x".repeat((1 << 28) - 16);
try {
s = "x".repeat((1 << 30) - 1 - 24);
} catch (e) {
}
var s = "x".repeat(%StringMaxLength());
assertThrows(() => f(s), RangeError);
})();
......@@ -93,10 +89,6 @@
assertEquals("abcde", f("de"));
assertEquals("abcde", f("de"));
%OptimizeFunctionOnNextCall(f);
var s = "x".repeat((1 << 28) - 16);
try {
s = "x".repeat((1 << 30) - 1 - 24);
} catch (e) {
}
var s = "x".repeat(%StringMaxLength());
assertThrows(() => f(s), RangeError);
})();
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment