--- /dev/null
+/*
+ * 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. AND ITS CONTRIBUTORS ``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 ITS 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 "BytecodeBasicBlock.h"
+
+#include "CodeBlock.h"
+#include "JSCInlines.h"
+#include "PreciseJumpTargets.h"
+
+namespace JSC {
+
+static bool isBranch(OpcodeID opcodeID)
+{
+ switch (opcodeID) {
+ case op_jmp:
+ case op_jtrue:
+ case op_jfalse:
+ case op_jeq_null:
+ case op_jneq_null:
+ 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:
+ case op_switch_imm:
+ case op_switch_char:
+ case op_switch_string:
+ case op_get_pnames:
+ case op_next_pname:
+ case op_check_has_instance:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static bool isUnconditionalBranch(OpcodeID opcodeID)
+{
+ switch (opcodeID) {
+ case op_jmp:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static bool isTerminal(OpcodeID opcodeID)
+{
+ switch (opcodeID) {
+ case op_ret:
+ case op_ret_object_or_this:
+ case op_end:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static bool isThrow(OpcodeID opcodeID)
+{
+ switch (opcodeID) {
+ case op_throw:
+ case op_throw_static_error:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static bool isJumpTarget(OpcodeID opcodeID, Vector<unsigned, 32>& jumpTargets, unsigned bytecodeOffset)
+{
+ if (opcodeID == op_catch)
+ return true;
+
+ for (unsigned i = 0; i < jumpTargets.size(); i++) {
+ if (bytecodeOffset == jumpTargets[i])
+ return true;
+ }
+ return false;
+}
+
+static void linkBlocks(BytecodeBasicBlock* predecessor, BytecodeBasicBlock* successor)
+{
+ predecessor->addSuccessor(successor);
+ successor->addPredecessor(predecessor);
+}
+
+void computeBytecodeBasicBlocks(CodeBlock* codeBlock, Vector<RefPtr<BytecodeBasicBlock> >& basicBlocks)
+{
+ Vector<unsigned, 32> jumpTargets;
+ computePreciseJumpTargets(codeBlock, jumpTargets);
+
+ // Create the entry and exit basic blocks.
+ BytecodeBasicBlock* entry = new BytecodeBasicBlock(BytecodeBasicBlock::EntryBlock);
+ basicBlocks.append(adoptRef(entry));
+ BytecodeBasicBlock* exit = new BytecodeBasicBlock(BytecodeBasicBlock::ExitBlock);
+
+ // Find basic block boundaries.
+ BytecodeBasicBlock* current = new BytecodeBasicBlock(0, 0);
+ linkBlocks(entry, current);
+ basicBlocks.append(adoptRef(current));
+
+ bool nextInstructionIsLeader = false;
+
+ 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);
+ unsigned opcodeLength = opcodeLengths[opcodeID];
+
+ bool createdBlock = false;
+ // If the current bytecode is a jump target, then it's the leader of its own basic block.
+ if (isJumpTarget(opcodeID, jumpTargets, bytecodeOffset) || nextInstructionIsLeader) {
+ BytecodeBasicBlock* block = new BytecodeBasicBlock(bytecodeOffset, opcodeLength);
+ basicBlocks.append(adoptRef(block));
+ current = block;
+ createdBlock = true;
+ nextInstructionIsLeader = false;
+ bytecodeOffset += opcodeLength;
+ }
+
+ // If the current bytecode is a branch or a return, then the next instruction is the leader of its own basic block.
+ if (isBranch(opcodeID) || isTerminal(opcodeID) || isThrow(opcodeID))
+ nextInstructionIsLeader = true;
+
+ if (createdBlock)
+ continue;
+
+ // Otherwise, just add to the length of the current block.
+ current->addBytecodeLength(opcodeLength);
+ bytecodeOffset += opcodeLength;
+ }
+
+ // Link basic blocks together.
+ for (unsigned i = 0; i < basicBlocks.size(); i++) {
+ BytecodeBasicBlock* block = basicBlocks[i].get();
+
+ if (block->isEntryBlock() || block->isExitBlock())
+ continue;
+
+ bool fallsThrough = true;
+ for (unsigned bytecodeOffset = block->leaderBytecodeOffset(); bytecodeOffset < block->leaderBytecodeOffset() + block->totalBytecodeLength();) {
+ const Instruction& currentInstruction = instructionsBegin[bytecodeOffset];
+ OpcodeID opcodeID = interpreter->getOpcodeID(currentInstruction.u.opcode);
+ unsigned opcodeLength = opcodeLengths[opcodeID];
+ // If we found a terminal bytecode, link to the exit block.
+ if (isTerminal(opcodeID)) {
+ ASSERT(bytecodeOffset + opcodeLength == block->leaderBytecodeOffset() + block->totalBytecodeLength());
+ linkBlocks(block, exit);
+ fallsThrough = false;
+ break;
+ }
+
+ // If we found a throw, get the HandlerInfo for this instruction to see where we will jump.
+ // If there isn't one, treat this throw as a terminal. This is true even if we have a finally
+ // block because the finally block will create its own catch, which will generate a HandlerInfo.
+ if (isThrow(opcodeID)) {
+ ASSERT(bytecodeOffset + opcodeLength == block->leaderBytecodeOffset() + block->totalBytecodeLength());
+ HandlerInfo* handler = codeBlock->handlerForBytecodeOffset(bytecodeOffset);
+ fallsThrough = false;
+ if (!handler) {
+ linkBlocks(block, exit);
+ break;
+ }
+ for (unsigned i = 0; i < basicBlocks.size(); i++) {
+ BytecodeBasicBlock* otherBlock = basicBlocks[i].get();
+ if (handler->target == otherBlock->leaderBytecodeOffset()) {
+ linkBlocks(block, otherBlock);
+ break;
+ }
+ }
+ break;
+ }
+
+ // If we found a branch, link to the block(s) that we jump to.
+ if (isBranch(opcodeID)) {
+ ASSERT(bytecodeOffset + opcodeLength == block->leaderBytecodeOffset() + block->totalBytecodeLength());
+ Vector<unsigned, 1> bytecodeOffsetsJumpedTo;
+ findJumpTargetsForBytecodeOffset(codeBlock, bytecodeOffset, bytecodeOffsetsJumpedTo);
+
+ for (unsigned i = 0; i < basicBlocks.size(); i++) {
+ BytecodeBasicBlock* otherBlock = basicBlocks[i].get();
+ if (bytecodeOffsetsJumpedTo.contains(otherBlock->leaderBytecodeOffset()))
+ linkBlocks(block, otherBlock);
+ }
+
+ if (isUnconditionalBranch(opcodeID))
+ fallsThrough = false;
+
+ break;
+ }
+ bytecodeOffset += opcodeLength;
+ }
+
+ // If we fall through then link to the next block in program order.
+ if (fallsThrough) {
+ ASSERT(i + 1 < basicBlocks.size());
+ BytecodeBasicBlock* nextBlock = basicBlocks[i + 1].get();
+ linkBlocks(block, nextBlock);
+ }
+ }
+
+ basicBlocks.append(adoptRef(exit));
+}
+
+} // namespace JSC
projects / apple / javascriptcore.git / blobdiff