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      1 /*
      2  * Copyright (C) 2010 Apple Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
     14  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
     15  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
     17  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     18  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     19  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     20  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     21  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     22  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
     23  * THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #include "config.h"
     27 #include "ThunkGenerators.h"
     28 
     29 #include "CodeBlock.h"
     30 #include <wtf/text/StringImpl.h>
     31 #include "SpecializedThunkJIT.h"
     32 
     33 #if ENABLE(JIT)
     34 
     35 namespace JSC {
     36 
     37 static void stringCharLoad(SpecializedThunkJIT& jit)
     38 {
     39     // load string
     40     jit.loadJSStringArgument(SpecializedThunkJIT::ThisArgument, SpecializedThunkJIT::regT0);
     41     // regT0 now contains this, and is a non-rope JSString*
     42 
     43     // Load string length to regT2, and start the process of loading the data pointer into regT0
     44     jit.load32(MacroAssembler::Address(SpecializedThunkJIT::regT0, ThunkHelpers::jsStringLengthOffset()), SpecializedThunkJIT::regT2);
     45     jit.loadPtr(MacroAssembler::Address(SpecializedThunkJIT::regT0, ThunkHelpers::jsStringValueOffset()), SpecializedThunkJIT::regT0);
     46     jit.loadPtr(MacroAssembler::Address(SpecializedThunkJIT::regT0, ThunkHelpers::stringImplDataOffset()), SpecializedThunkJIT::regT0);
     47 
     48     // load index
     49     jit.loadInt32Argument(0, SpecializedThunkJIT::regT1); // regT1 contains the index
     50 
     51     // Do an unsigned compare to simultaneously filter negative indices as well as indices that are too large
     52     jit.appendFailure(jit.branch32(MacroAssembler::AboveOrEqual, SpecializedThunkJIT::regT1, SpecializedThunkJIT::regT2));
     53 
     54     // Load the character
     55     jit.load16(MacroAssembler::BaseIndex(SpecializedThunkJIT::regT0, SpecializedThunkJIT::regT1, MacroAssembler::TimesTwo, 0), SpecializedThunkJIT::regT0);
     56 }
     57 
     58 static void charToString(SpecializedThunkJIT& jit, JSGlobalData* globalData, MacroAssembler::RegisterID src, MacroAssembler::RegisterID dst, MacroAssembler::RegisterID scratch)
     59 {
     60     jit.appendFailure(jit.branch32(MacroAssembler::AboveOrEqual, src, MacroAssembler::TrustedImm32(0x100)));
     61     jit.move(MacroAssembler::TrustedImmPtr(globalData->smallStrings.singleCharacterStrings()), scratch);
     62     jit.loadPtr(MacroAssembler::BaseIndex(scratch, src, MacroAssembler::ScalePtr, 0), dst);
     63     jit.appendFailure(jit.branchTestPtr(MacroAssembler::Zero, dst));
     64 }
     65 
     66 MacroAssemblerCodePtr charCodeAtThunkGenerator(JSGlobalData* globalData, ExecutablePool* pool)
     67 {
     68     SpecializedThunkJIT jit(1, globalData, pool);
     69     stringCharLoad(jit);
     70     jit.returnInt32(SpecializedThunkJIT::regT0);
     71     return jit.finalize(globalData->jitStubs->ctiNativeCall());
     72 }
     73 
     74 MacroAssemblerCodePtr charAtThunkGenerator(JSGlobalData* globalData, ExecutablePool* pool)
     75 {
     76     SpecializedThunkJIT jit(1, globalData, pool);
     77     stringCharLoad(jit);
     78     charToString(jit, globalData, SpecializedThunkJIT::regT0, SpecializedThunkJIT::regT0, SpecializedThunkJIT::regT1);
     79     jit.returnJSCell(SpecializedThunkJIT::regT0);
     80     return jit.finalize(globalData->jitStubs->ctiNativeCall());
     81 }
     82 
     83 MacroAssemblerCodePtr fromCharCodeThunkGenerator(JSGlobalData* globalData, ExecutablePool* pool)
     84 {
     85     SpecializedThunkJIT jit(1, globalData, pool);
     86     // load char code
     87     jit.loadInt32Argument(0, SpecializedThunkJIT::regT0);
     88     charToString(jit, globalData, SpecializedThunkJIT::regT0, SpecializedThunkJIT::regT0, SpecializedThunkJIT::regT1);
     89     jit.returnJSCell(SpecializedThunkJIT::regT0);
     90     return jit.finalize(globalData->jitStubs->ctiNativeCall());
     91 }
     92 
     93 MacroAssemblerCodePtr sqrtThunkGenerator(JSGlobalData* globalData, ExecutablePool* pool)
     94 {
     95     SpecializedThunkJIT jit(1, globalData, pool);
     96     if (!jit.supportsFloatingPointSqrt())
     97         return globalData->jitStubs->ctiNativeCall();
     98 
     99     jit.loadDoubleArgument(0, SpecializedThunkJIT::fpRegT0, SpecializedThunkJIT::regT0);
    100     jit.sqrtDouble(SpecializedThunkJIT::fpRegT0, SpecializedThunkJIT::fpRegT0);
    101     jit.returnDouble(SpecializedThunkJIT::fpRegT0);
    102     return jit.finalize(globalData->jitStubs->ctiNativeCall());
    103 }
    104 
    105 static const double oneConstant = 1.0;
    106 static const double negativeHalfConstant = -0.5;
    107 
    108 MacroAssemblerCodePtr powThunkGenerator(JSGlobalData* globalData, ExecutablePool* pool)
    109 {
    110     SpecializedThunkJIT jit(2, globalData, pool);
    111     if (!jit.supportsFloatingPoint())
    112         return globalData->jitStubs->ctiNativeCall();
    113 
    114     jit.loadDouble(&oneConstant, SpecializedThunkJIT::fpRegT1);
    115     jit.loadDoubleArgument(0, SpecializedThunkJIT::fpRegT0, SpecializedThunkJIT::regT0);
    116     MacroAssembler::Jump nonIntExponent;
    117     jit.loadInt32Argument(1, SpecializedThunkJIT::regT0, nonIntExponent);
    118     jit.appendFailure(jit.branch32(MacroAssembler::LessThan, SpecializedThunkJIT::regT0, MacroAssembler::TrustedImm32(0)));
    119 
    120     MacroAssembler::Jump exponentIsZero = jit.branchTest32(MacroAssembler::Zero, SpecializedThunkJIT::regT0);
    121     MacroAssembler::Label startLoop(jit.label());
    122 
    123     MacroAssembler::Jump exponentIsEven = jit.branchTest32(MacroAssembler::Zero, SpecializedThunkJIT::regT0, MacroAssembler::TrustedImm32(1));
    124     jit.mulDouble(SpecializedThunkJIT::fpRegT0, SpecializedThunkJIT::fpRegT1);
    125     exponentIsEven.link(&jit);
    126     jit.mulDouble(SpecializedThunkJIT::fpRegT0, SpecializedThunkJIT::fpRegT0);
    127     jit.rshift32(MacroAssembler::TrustedImm32(1), SpecializedThunkJIT::regT0);
    128     jit.branchTest32(MacroAssembler::NonZero, SpecializedThunkJIT::regT0).linkTo(startLoop, &jit);
    129 
    130     exponentIsZero.link(&jit);
    131 
    132     {
    133         SpecializedThunkJIT::JumpList doubleResult;
    134         jit.branchConvertDoubleToInt32(SpecializedThunkJIT::fpRegT1, SpecializedThunkJIT::regT0, doubleResult, SpecializedThunkJIT::fpRegT0);
    135         jit.returnInt32(SpecializedThunkJIT::regT0);
    136         doubleResult.link(&jit);
    137         jit.returnDouble(SpecializedThunkJIT::fpRegT1);
    138     }
    139 
    140     if (jit.supportsFloatingPointSqrt()) {
    141         nonIntExponent.link(&jit);
    142         jit.loadDouble(&negativeHalfConstant, SpecializedThunkJIT::fpRegT3);
    143         jit.loadDoubleArgument(1, SpecializedThunkJIT::fpRegT2, SpecializedThunkJIT::regT0);
    144         jit.appendFailure(jit.branchDouble(MacroAssembler::DoubleLessThanOrEqual, SpecializedThunkJIT::fpRegT0, SpecializedThunkJIT::fpRegT1));
    145         jit.appendFailure(jit.branchDouble(MacroAssembler::DoubleNotEqualOrUnordered, SpecializedThunkJIT::fpRegT2, SpecializedThunkJIT::fpRegT3));
    146         jit.sqrtDouble(SpecializedThunkJIT::fpRegT0, SpecializedThunkJIT::fpRegT0);
    147         jit.divDouble(SpecializedThunkJIT::fpRegT0, SpecializedThunkJIT::fpRegT1);
    148 
    149         SpecializedThunkJIT::JumpList doubleResult;
    150         jit.branchConvertDoubleToInt32(SpecializedThunkJIT::fpRegT1, SpecializedThunkJIT::regT0, doubleResult, SpecializedThunkJIT::fpRegT0);
    151         jit.returnInt32(SpecializedThunkJIT::regT0);
    152         doubleResult.link(&jit);
    153         jit.returnDouble(SpecializedThunkJIT::fpRegT1);
    154     } else
    155         jit.appendFailure(nonIntExponent);
    156 
    157     return jit.finalize(globalData->jitStubs->ctiNativeCall());
    158 }
    159 
    160 }
    161 
    162 #endif // ENABLE(JIT)
    163