webkitgtk-2.10.2webkitgtk-2.10.2

1 files changed, 133 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/bytecode/PreciseJumpTargets.cpp b/Source/JavaScriptCore/bytecode/PreciseJumpTargets.cpp
new file mode 100644
index 000000000..414dfd97d
--- /dev/null
+++ b/Source/JavaScriptCore/bytecode/PreciseJumpTargets.cpp
@@ -0,0 +1,133 @@
+/*
+ * Copyright (C) 2013 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#include "config.h"
+#include "PreciseJumpTargets.h"
+
+#include "JSCInlines.h"
+
+namespace JSC {
+
+template <size_t vectorSize>
+static void getJumpTargetsForBytecodeOffset(CodeBlock* codeBlock, Interpreter* interpreter, Instruction* instructionsBegin, unsigned bytecodeOffset, Vector<unsigned, vectorSize>& out)
+{
+    OpcodeID opcodeID = interpreter->getOpcodeID(instructionsBegin[bytecodeOffset].u.opcode);
+    Instruction* current = instructionsBegin + bytecodeOffset;
+    switch (opcodeID) {
+    case op_jmp:
+        out.append(bytecodeOffset + current[1].u.operand);
+        break;
+    case op_jtrue:
+    case op_jfalse:
+    case op_jeq_null:
+    case op_jneq_null:
+        out.append(bytecodeOffset + current[2].u.operand);
+        break;
+    case op_jneq_ptr:
+    case op_jless:
+    case op_jlesseq:
+    case op_jgreater:
+    case op_jgreatereq:
+    case op_jnless:
+    case op_jnlesseq:
+    case op_jngreater:
+    case op_jngreatereq:
+        out.append(bytecodeOffset + current[3].u.operand);
+        break;
+    case op_switch_imm:
+    case op_switch_char: {
+        SimpleJumpTable& table = codeBlock->switchJumpTable(current[1].u.operand);
+        for (unsigned i = table.branchOffsets.size(); i--;)
+            out.append(bytecodeOffset + table.branchOffsets[i]);
+        out.append(bytecodeOffset + current[2].u.operand);
+        break;
+    }
+    case op_switch_string: {
+        StringJumpTable& table = codeBlock->stringSwitchJumpTable(current[1].u.operand);
+        StringJumpTable::StringOffsetTable::iterator iter = table.offsetTable.begin();
+        StringJumpTable::StringOffsetTable::iterator end = table.offsetTable.end();
+        for (; iter != end; ++iter)
+            out.append(bytecodeOffset + iter->value.branchOffset);
+        out.append(bytecodeOffset + current[2].u.operand);
+        break;
+    }
+    case op_check_has_instance:
+        out.append(bytecodeOffset + current[4].u.operand);
+        break;
+    case op_loop_hint:
+        out.append(bytecodeOffset);
+        break;
+    default:
+        break;
+    }
+}
+
+void computePreciseJumpTargets(CodeBlock* codeBlock, Vector<unsigned, 32>& out)
+{
+    ASSERT(out.isEmpty());
+    
+    // We will derive a superset of the jump targets that the code block thinks it has.
+    // So, if the code block claims there are none, then we are done.
+    if (!codeBlock->numberOfJumpTargets())
+        return;
+    
+    for (unsigned i = codeBlock->numberOfExceptionHandlers(); i--;)
+        out.append(codeBlock->exceptionHandler(i).target);
+    
+    Interpreter* interpreter = codeBlock->vm()->interpreter;
+    Instruction* instructionsBegin = codeBlock->instructions().begin();
+    unsigned instructionCount = codeBlock->instructions().size();
+    for (unsigned bytecodeOffset = 0; bytecodeOffset < instructionCount;) {
+        OpcodeID opcodeID = interpreter->getOpcodeID(instructionsBegin[bytecodeOffset].u.opcode);
+        getJumpTargetsForBytecodeOffset(codeBlock, interpreter, instructionsBegin, bytecodeOffset, out);
+        bytecodeOffset += opcodeLengths[opcodeID];
+    }
+    
+    std::sort(out.begin(), out.end());
+    
+    // We will have duplicates, and we must remove them.
+    unsigned toIndex = 0;
+    unsigned fromIndex = 0;
+    unsigned lastValue = UINT_MAX;
+    while (fromIndex < out.size()) {
+        unsigned value = out[fromIndex++];
+        if (value == lastValue)
+            continue;
+        out[toIndex++] = value;
+        lastValue = value;
+    }
+    out.resize(toIndex);
+    out.shrinkToFit();
+}
+
+void findJumpTargetsForBytecodeOffset(CodeBlock* codeBlock, unsigned bytecodeOffset, Vector<unsigned, 1>& out)
+{
+    Interpreter* interpreter = codeBlock->vm()->interpreter;
+    Instruction* instructionsBegin = codeBlock->instructions().begin();
+    getJumpTargetsForBytecodeOffset(codeBlock, interpreter, instructionsBegin, bytecodeOffset, out);
+}
+
+} // namespace JSC
+