Attachment 341428 Details for Bug 186023 – Patch

[patch] Patch

bug-186023-20180528035504.patch (text/plain), 4.79 KB, created by Yusuke Suzuki on 2018-05-27 11:55:05 PDT

(hide)

Description:

Filename:

MIME Type:

Creator: Yusuke Suzuki

Created: 2018-05-27 11:55:05 PDT

Size: 4.79 KB

patch

obsolete

>Subversion Revision: 232228
>diff --git a/Source/JavaScriptCore/ChangeLog b/Source/JavaScriptCore/ChangeLog
>index af3750dbd8078b60b991510cce07a747579a80f1..323bd1d5446b1fc66c46115574882751941cc299 100644
>--- a/Source/JavaScriptCore/ChangeLog
>+++ b/Source/JavaScriptCore/ChangeLog
>@@ -1,3 +1,16 @@
>+2018-05-27  Yusuke Suzuki  <utatane.tea@gmail.com>
>+
>+        [WTF] Add clz32 / clz64 for MSVC
>+        https://bugs.webkit.org/show_bug.cgi?id=186023
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        Move clz32 and clz64 to WTF.
>+
>+        * runtime/MathCommon.h:
>+        (JSC::clz32): Deleted.
>+        (JSC::clz64): Deleted.
>+
> 2018-05-26  Yusuke Suzuki  <utatane.tea@gmail.com>
> 
>         [JSC] Rename Array#flatten to flat
>diff --git a/Source/WTF/ChangeLog b/Source/WTF/ChangeLog
>index 229f30316c5817b1815a85799a77a8a64c0d99b8..b5e4a138d864af54ff2823875e55eff3425e4beb 100644
>--- a/Source/WTF/ChangeLog
>+++ b/Source/WTF/ChangeLog
>@@ -1,3 +1,18 @@
>+2018-05-27  Yusuke Suzuki  <utatane.tea@gmail.com>
>+
>+        [WTF] Add clz32 / clz64 for MSVC
>+        https://bugs.webkit.org/show_bug.cgi?id=186023
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        This patch adds efficient implementations of clz32 and clz64 for MSVC.
>+        While MSVC has _lzcnt intrinsic, it is only valid if the CPU has lzcnt instruction.
>+        Instead of checking cpuid here, we just use _BitScanReverse and _BitScanReverse64.
>+
>+        * wtf/MathExtras.h:
>+        (WTF::clz32):
>+        (WTF::clz64):
>+
> 2018-05-26  Filip Pizlo  <fpizlo@apple.com>
> 
>         testair sometimes crashes due to races in initialization of ARC4RandomNumberGenerator
>diff --git a/Source/JavaScriptCore/runtime/MathCommon.h b/Source/JavaScriptCore/runtime/MathCommon.h
>index 0fdc7c3565ce8ab1ddec51defd4cf3852c399855..e9194612142a537446e66d986c64e806439f2059 100644
>--- a/Source/JavaScriptCore/runtime/MathCommon.h
>+++ b/Source/JavaScriptCore/runtime/MathCommon.h
>@@ -47,44 +47,6 @@ inline constexpr double minSafeInteger()
>     return -9007199254740991.0;
> }
> 
>-inline int clz32(uint32_t number)
>-{
>-#if COMPILER(GCC_OR_CLANG)
>-    int zeroCount = 32;
>-    if (number)
>-        zeroCount = __builtin_clz(number);
>-    return zeroCount;
>-#else
>-    int zeroCount = 0;
>-    for (int i = 31; i >= 0; i--) {
>-        if (!(number >> i))
>-            zeroCount++;
>-        else
>-            break;
>-    }
>-    return zeroCount;
>-#endif
>-}
>-
>-inline int clz64(uint64_t number)
>-{
>-#if COMPILER(GCC_OR_CLANG)
>-    int zeroCount = 64;
>-    if (number)
>-        zeroCount = __builtin_clzll(number);
>-    return zeroCount;
>-#else
>-    int zeroCount = 0;
>-    for (int i = 63; i >= 0; i--) {
>-        if (!(number >> i))
>-            zeroCount++;
>-        else
>-            break;
>-    }
>-    return zeroCount;
>-#endif
>-}
>-
> // This in the ToInt32 operation is defined in section 9.5 of the ECMA-262 spec.
> // Note that this operation is identical to ToUInt32 other than to interpretation
> // of the resulting bit-pattern (as such this method is also called to implement
>diff --git a/Source/WTF/wtf/MathExtras.h b/Source/WTF/wtf/MathExtras.h
>index 80d3050cbf17bcb3fff72645cb25885de165790f..1aaf8d6c1936dd3e3423c0c151fa75253c5bdeaa 100644
>--- a/Source/WTF/wtf/MathExtras.h
>+++ b/Source/WTF/wtf/MathExtras.h
>@@ -524,6 +524,56 @@ void shuffleVector(VectorType& vector, const RandomFunc& randomFunc)
>     shuffleVector(vector, vector.size(), randomFunc);
> }
> 
>+inline unsigned clz32(uint32_t number)
>+{
>+#if COMPILER(GCC_OR_CLANG)
>+    if (number)
>+        return __builtin_clz(number);
>+    return 32;
>+#elif COMPILER(MSVC)
>+    // Visual Studio 2008 or upper have __lzcnt But we can't detect AVX at compile time.
>+    // So we use bsr to calculate clz
>+    unsigned long ret = 0;
>+    if (_BitScanReverse(&ret, number))
>+        return 31 - ret;
>+    return 32;
>+#else
>+    unsigned zeroCount = 0;
>+    for (int i = 31; i >= 0; i--) {
>+        if (!(number >> i))
>+            zeroCount++;
>+        else
>+            break;
>+    }
>+    return zeroCount;
>+#endif
>+}
>+
>+inline unsigned clz64(uint64_t number)
>+{
>+#if COMPILER(GCC_OR_CLANG)
>+    if (number)
>+        return __builtin_clzll(number);
>+    return 64;
>+#elif COMPILER(MSVC)
>+    // Visual Studio 2008 or upper have __lzcnt But we can't detect AVX at compile time.
>+    // So we use bsr to calculate clz
>+    unsigned long ret = 0;
>+    if (_BitScanReverse64(&ret, number))
>+        return 63 - ret;
>+    return 64;
>+#else
>+    unsigned zeroCount = 0;
>+    for (int i = 63; i >= 0; i--) {
>+        if (!(number >> i))
>+            zeroCount++;
>+        else
>+            break;
>+    }
>+    return zeroCount;
>+#endif
>+}
>+
> } // namespace WTF
> 
> using WTF::opaque;
>@@ -531,5 +581,7 @@ using WTF::preciseIndexMaskPtr;
> using WTF::preciseIndexMaskShift;
> using WTF::preciseIndexMaskShiftForSize;
> using WTF::shuffleVector;
>+using WTF::clz32;
>+using WTF::clz64;
> 
> #endif // #ifndef WTF_MathExtras_h

Flags:

dbates: review+

Actions: View | Formatted Diff | Diff

Attachments on bug 186023: 341428