[JSC] Use UCPURegister argument to remove zero extension in JIT code

Constellation · Constellation · commit 6cdd1b3f9e88 · 2021-07-30T08:41:25.000Z
https://bugs.webkit.org/show_bug.cgi?id=228625 Reviewed by Robin Morisset. Yarr JIT code emits zeroExtend32ToWord for some arguments, but this is not necessary if argument is defined as UCPURegister. In that case, caller guarantees that top 32bits are cleared. * yarr/YarrJIT.cpp: * yarr/YarrJIT.h: Canonical link: https://commits.webkit.org/240105@main git-svn-id: https://svn.webkit.org/repository/webkit/trunk@280470 268f45cc-cd09-0410-ab3c-d52691b4dbfc
diff --git a/Source/JavaScriptCore/ChangeLog b/Source/JavaScriptCore/ChangeLog
@@ -1,3 +1,17 @@
+2021-07-30  Yusuke Suzuki  <ysuzuki@apple.com>
+
+        [JSC] Use UCPURegister argument to remove zero extension in JIT code
+        https://bugs.webkit.org/show_bug.cgi?id=228625
+
+        Reviewed by Robin Morisset.
+
+        Yarr JIT code emits zeroExtend32ToWord for some arguments, but this is not necessary if
+        argument is defined as UCPURegister. In that case, caller guarantees that top 32bits are
+        cleared.
+
+        * yarr/YarrJIT.cpp:
+        * yarr/YarrJIT.h:
+
 2021-07-29  Myles C. Maxfield  <mmaxfield@apple.com>
 
         Stop building WebGPU and the WHLSL compiler to decrease binary size
diff --git a/Source/JavaScriptCore/yarr/YarrJIT.cpp b/Source/JavaScriptCore/yarr/YarrJIT.cpp
@@ -3972,9 +3972,6 @@ class YarrGenerator final : public YarrJITInfo, private MacroAssembler {
             push(X86Registers::r14);
             push(X86Registers::r15);
         }
-        // The ABI doesn't guarantee the upper bits are zero on unsigned arguments, so clear them ourselves.
-        zeroExtend32ToWord(index, index);
-        zeroExtend32ToWord(length, length);
 #if OS(WINDOWS)
         if (m_compileMode == JITCompileMode::IncludeSubpatterns)
             loadPtr(Address(X86Registers::ebp, 6 * sizeof(void*)), output);
@@ -3991,10 +3988,6 @@ class YarrGenerator final : public YarrJITInfo, private MacroAssembler {
             move(TrustedImm32(0xd800), leadingSurrogateTag);
             move(TrustedImm32(0xdc00), trailingSurrogateTag);
         }
-
-        // The ABI doesn't guarantee the upper bits are zero on unsigned arguments, so clear them ourselves.
-        zeroExtend32ToWord(index, index);
-        zeroExtend32ToWord(length, length);
 #elif CPU(ARM_THUMB2)
         push(ARMRegisters::r4);
         push(ARMRegisters::r5);
diff --git a/Source/JavaScriptCore/yarr/YarrJIT.h b/Source/JavaScriptCore/yarr/YarrJIT.h
@@ -103,18 +103,18 @@ class BoyerMooreByteVector : public std::array<uint8_t, BoyerMooreBitmap::mapSiz
 };
 
 #if CPU(ARM64E)
-extern "C" EncodedMatchResult vmEntryToYarrJIT(const void* input, unsigned start, unsigned length, int* output, MatchingContextHolder* matchingContext, const void* codePtr);
+extern "C" EncodedMatchResult vmEntryToYarrJIT(const void* input, UCPURegister start, UCPURegister length, int* output, MatchingContextHolder* matchingContext, const void* codePtr);
 extern "C" void vmEntryToYarrJITAfter(void);
 #endif
 
 class YarrCodeBlock {
     WTF_MAKE_FAST_ALLOCATED;
     WTF_MAKE_NONCOPYABLE(YarrCodeBlock);
 
-    using YarrJITCode8 = EncodedMatchResult (*)(const LChar* input, unsigned start, unsigned length, int* output, MatchingContextHolder& matchingContext) YARR_CALL;
-    using YarrJITCode16 = EncodedMatchResult (*)(const UChar* input, unsigned start, unsigned length, int* output, MatchingContextHolder& matchingContext) YARR_CALL;
-    using YarrJITCodeMatchOnly8 = EncodedMatchResult (*)(const LChar* input, unsigned start, unsigned length, void*, MatchingContextHolder& matchingContext) YARR_CALL;
-    using YarrJITCodeMatchOnly16 = EncodedMatchResult (*)(const UChar* input, unsigned start, unsigned length, void*, MatchingContextHolder& matchingContext) YARR_CALL;
+    using YarrJITCode8 = EncodedMatchResult (*)(const LChar* input, UCPURegister start, UCPURegister length, int* output, MatchingContextHolder& matchingContext) YARR_CALL;
+    using YarrJITCode16 = EncodedMatchResult (*)(const UChar* input, UCPURegister start, UCPURegister length, int* output, MatchingContextHolder& matchingContext) YARR_CALL;
+    using YarrJITCodeMatchOnly8 = EncodedMatchResult (*)(const LChar* input, UCPURegister start, UCPURegister length, void*, MatchingContextHolder& matchingContext) YARR_CALL;
+    using YarrJITCodeMatchOnly16 = EncodedMatchResult (*)(const UChar* input, UCPURegister start, UCPURegister length, void*, MatchingContextHolder& matchingContext) YARR_CALL;
 
 public:
     YarrCodeBlock() = default;
