runtime/CommonSlowPaths.h

   1 /*
   2  * Copyright (C) 2011, 2012 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. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #ifndef CommonSlowPaths_h
  27 #define CommonSlowPaths_h
  28
  29 #include "CodeBlock.h"
  30 #include "CodeSpecializationKind.h"
  31 #include "ExceptionHelpers.h"
  32 #include "JSArray.h"
  33
  34 namespace JSC {
  35
  36 // The purpose of this namespace is to include slow paths that are shared
  37 // between the interpreter and baseline JIT. They are written to be agnostic
  38 // with respect to the slow-path calling convention, but they do rely on the
  39 // JS code being executed more-or-less directly from bytecode (so the call
  40 // frame layout is unmodified, making it potentially awkward to use these
  41 // from any optimizing JIT, like the DFG).
  42
  43 namespace CommonSlowPaths {
  44
  45 ALWAYS_INLINE ExecState* arityCheckFor(ExecState* exec, RegisterFile* registerFile, CodeSpecializationKind kind)
  46 {
  47     JSFunction* callee = jsCast<JSFunction*>(exec->callee());
  48     ASSERT(!callee->isHostFunction());
  49     CodeBlock* newCodeBlock = &callee->jsExecutable()->generatedBytecodeFor(kind);
  50     int argumentCountIncludingThis = exec->argumentCountIncludingThis();
  51
  52     // This ensures enough space for the worst case scenario of zero arguments passed by the caller.
  53     if (!registerFile->grow(exec->registers() + newCodeBlock->numParameters() + newCodeBlock->m_numCalleeRegisters))
  54         return 0;
  55
  56     ASSERT(argumentCountIncludingThis < newCodeBlock->numParameters());
  57
  58     // Too few arguments -- copy call frame and arguments, then fill in missing arguments with undefined.
  59     size_t delta = newCodeBlock->numParameters() - argumentCountIncludingThis;
  60     Register* src = exec->registers();
  61     Register* dst = exec->registers() + delta;
  62
  63     int i;
  64     int end = -ExecState::offsetFor(argumentCountIncludingThis);
  65     for (i = -1; i >= end; --i)
  66         dst[i] = src[i];
  67
  68     end -= delta;
  69     for ( ; i >= end; --i)
  70         dst[i] = jsUndefined();
  71
  72     ExecState* newExec = ExecState::create(dst);
  73     ASSERT((void*)newExec <= registerFile->end());
  74     return newExec;
  75 }
  76
  77 ALWAYS_INLINE bool opInstanceOfSlow(ExecState* exec, JSValue value, JSValue baseVal, JSValue proto)
  78 {
  79     ASSERT(!value.isCell() || !baseVal.isCell() || !proto.isCell()
  80            || !value.isObject() || !baseVal.isObject() || !proto.isObject()
  81            || !asObject(baseVal)->structure()->typeInfo().implementsDefaultHasInstance());
  82
  83
  84     // ECMA-262 15.3.5.3:
  85     // Throw an exception either if baseVal is not an object, or if it does not implement 'HasInstance' (i.e. is a function).
  86     TypeInfo typeInfo(UnspecifiedType);
  87     if (!baseVal.isObject() || !(typeInfo = asObject(baseVal)->structure()->typeInfo()).implementsHasInstance()) {
  88         exec->globalData().exception = createInvalidParamError(exec, "instanceof", baseVal);
  89         return false;
  90     }
  91     ASSERT(typeInfo.type() != UnspecifiedType);
  92
  93     if (!typeInfo.overridesHasInstance() && !value.isObject())
  94         return false;
  95
  96     return asObject(baseVal)->methodTable()->hasInstance(asObject(baseVal), exec, value, proto);
  97 }
  98
  99 inline bool opIn(ExecState* exec, JSValue propName, JSValue baseVal)
 100 {
 101     if (!baseVal.isObject()) {
 102         exec->globalData().exception = createInvalidParamError(exec, "in", baseVal);
 103         return false;
 104     }
 105
 106     JSObject* baseObj = asObject(baseVal);
 107
 108     uint32_t i;
 109     if (propName.getUInt32(i))
 110         return baseObj->hasProperty(exec, i);
 111
 112     Identifier property(exec, propName.toString(exec)->value(exec));
 113     if (exec->globalData().exception)
 114         return false;
 115     return baseObj->hasProperty(exec, property);
 116 }
 117
 118 ALWAYS_INLINE JSValue opResolve(ExecState* exec, Identifier& ident)
 119 {
 120     ScopeChainNode* scopeChain = exec->scopeChain();
 121
 122     ScopeChainIterator iter = scopeChain->begin();
 123     ScopeChainIterator end = scopeChain->end();
 124     ASSERT(iter != end);
 125
 126     do {
 127         JSObject* o = iter->get();
 128         PropertySlot slot(o);
 129         if (o->getPropertySlot(exec, ident, slot))
 130             return slot.getValue(exec, ident);
 131     } while (++iter != end);
 132
 133     exec->globalData().exception = createUndefinedVariableError(exec, ident);
 134     return JSValue();
 135 }
 136
 137 ALWAYS_INLINE JSValue opResolveSkip(ExecState* exec, Identifier& ident, int skip)
 138 {
 139     ScopeChainNode* scopeChain = exec->scopeChain();
 140
 141     ScopeChainIterator iter = scopeChain->begin();
 142     ScopeChainIterator end = scopeChain->end();
 143     ASSERT(iter != end);
 144     CodeBlock* codeBlock = exec->codeBlock();
 145     bool checkTopLevel = codeBlock->codeType() == FunctionCode && codeBlock->needsFullScopeChain();
 146     ASSERT(skip || !checkTopLevel);
 147     if (checkTopLevel && skip--) {
 148         if (exec->uncheckedR(codeBlock->activationRegister()).jsValue())
 149             ++iter;
 150     }
 151     while (skip--) {
 152         ++iter;
 153         ASSERT(iter != end);
 154     }
 155     do {
 156         JSObject* o = iter->get();
 157         PropertySlot slot(o);
 158         if (o->getPropertySlot(exec, ident, slot))
 159             return slot.getValue(exec, ident);
 160     } while (++iter != end);
 161
 162     exec->globalData().exception = createUndefinedVariableError(exec, ident);
 163     return JSValue();
 164 }
 165
 166 ALWAYS_INLINE JSValue opResolveWithBase(ExecState* exec, Identifier& ident, Register& baseSlot)
 167 {
 168     ScopeChainNode* scopeChain = exec->scopeChain();
 169
 170     ScopeChainIterator iter = scopeChain->begin();
 171     ScopeChainIterator end = scopeChain->end();
 172
 173     // FIXME: add scopeDepthIsZero optimization
 174
 175     ASSERT(iter != end);
 176
 177     JSObject* base;
 178     do {
 179         base = iter->get();
 180         PropertySlot slot(base);
 181         if (base->getPropertySlot(exec, ident, slot)) {
 182             JSValue result = slot.getValue(exec, ident);
 183             if (exec->globalData().exception)
 184                 return JSValue();
 185
 186             baseSlot = JSValue(base);
 187             return result;
 188         }
 189         ++iter;
 190     } while (iter != end);
 191
 192     exec->globalData().exception = createUndefinedVariableError(exec, ident);
 193     return JSValue();
 194 }
 195
 196 ALWAYS_INLINE JSValue opResolveWithThis(ExecState* exec, Identifier& ident, Register& baseSlot)
 197 {
 198     ScopeChainNode* scopeChain = exec->scopeChain();
 199
 200     ScopeChainIterator iter = scopeChain->begin();
 201     ScopeChainIterator end = scopeChain->end();
 202
 203     // FIXME: add scopeDepthIsZero optimization
 204
 205     ASSERT(iter != end);
 206
 207     JSObject* base;
 208     do {
 209         base = iter->get();
 210         ++iter;
 211         PropertySlot slot(base);
 212         if (base->getPropertySlot(exec, ident, slot)) {
 213             JSValue result = slot.getValue(exec, ident);
 214             if (exec->globalData().exception)
 215                 return JSValue();
 216
 217             // All entries on the scope chain should be EnvironmentRecords (activations etc),
 218             // other then 'with' object, which are directly referenced from the scope chain,
 219             // and the global object. If we hit either an EnvironmentRecord or a global
 220             // object at the end of the scope chain, this is undefined. If we hit a non-
 221             // EnvironmentRecord within the scope chain, pass the base as the this value.
 222             if (iter == end || base->structure()->typeInfo().isEnvironmentRecord())
 223                 baseSlot = jsUndefined();
 224             else
 225                 baseSlot = JSValue(base);
 226             return result;
 227         }
 228     } while (iter != end);
 229
 230     exec->globalData().exception = createUndefinedVariableError(exec, ident);
 231     return JSValue();
 232 }
 233
 234 } } // namespace JSC::CommonSlowPaths
 235
 236 #endif // CommonSlowPaths_h
 237