1 files changed, 114 insertions, 0 deletions
diff --git a/Source/JavaScriptCore/b3/air/AirLowerEntrySwitch.cpp b/Source/JavaScriptCore/b3/air/AirLowerEntrySwitch.cpp
new file mode 100644
index 000000000..e14641da6
--- /dev/null
+++ b/Source/JavaScriptCore/b3/air/AirLowerEntrySwitch.cpp
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2016 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 "AirLowerEntrySwitch.h"
+
+#if ENABLE(B3_JIT)
+
+#include "AirBlockWorklist.h"
+#include "AirCode.h"
+#include "AirInstInlines.h"
+#include "AirPhaseScope.h"
+#include "B3Procedure.h"
+
+namespace JSC { namespace B3 { namespace Air {
+
+void lowerEntrySwitch(Code& code)
+{
+    PhaseScope phaseScope(code, "lowerEntrySwitch");
+    
+    // Figure out the set of blocks that should be duplicated.
+    BlockWorklist worklist;
+    for (BasicBlock* block : code) {
+        if (block->last().kind.opcode == EntrySwitch)
+            worklist.push(block);
+    }
+    
+    // It's possible that we don't have any EntrySwitches. That's fine.
+    if (worklist.seen().isEmpty()) {
+        Vector<FrequentedBlock> entrypoints(code.proc().numEntrypoints(), FrequentedBlock(code[0]));
+        code.setEntrypoints(WTFMove(entrypoints));
+        return;
+    }
+    
+    while (BasicBlock* block = worklist.pop())
+        worklist.pushAll(block->predecessors());
+    
+    RELEASE_ASSERT(worklist.saw(code[0]));
+    
+    Vector<FrequencyClass> entrypointFrequencies(code.proc().numEntrypoints(), FrequencyClass::Rare);
+    for (BasicBlock* block : code) {
+        if (block->last().kind.opcode != EntrySwitch)
+            continue;
+        for (unsigned entrypointIndex = code.proc().numEntrypoints(); entrypointIndex--;) {
+            entrypointFrequencies[entrypointIndex] = maxFrequency(
+                entrypointFrequencies[entrypointIndex],
+                block->successor(entrypointIndex).frequency());
+        }
+    }
+    
+    auto fixEntrySwitch = [&] (BasicBlock* block, unsigned entrypointIndex) {
+        if (block->last().kind.opcode != EntrySwitch)
+            return;
+        FrequentedBlock target = block->successor(entrypointIndex);
+        block->last().kind.opcode = Jump;
+        block->successors().resize(1);
+        block->successor(0) = target;
+    };
+    
+    // Now duplicate them.
+    Vector<FrequentedBlock> entrypoints;
+    entrypoints.append(FrequentedBlock(code[0], entrypointFrequencies[0]));
+    IndexMap<BasicBlock, BasicBlock*> map(code.size());
+    for (unsigned entrypointIndex = 1; entrypointIndex < code.proc().numEntrypoints(); ++entrypointIndex) {
+        map.clear();
+        for (BasicBlock* block : worklist.seen().values(code))
+            map[block] = code.addBlock(block->frequency());
+        entrypoints.append(FrequentedBlock(map[code[0]], entrypointFrequencies[entrypointIndex]));
+        for (BasicBlock* block : worklist.seen().values(code)) {
+            BasicBlock* newBlock = map[block];
+            for (const Inst& inst : *block)
+                newBlock->appendInst(inst);
+            newBlock->successors() = block->successors();
+            for (BasicBlock*& successor : newBlock->successorBlocks()) {
+                if (BasicBlock* replacement = map[successor])
+                    successor = replacement;
+            }
+            fixEntrySwitch(newBlock, entrypointIndex);
+        }
+    }
+    for (BasicBlock* block : worklist.seen().values(code))
+        fixEntrySwitch(block, 0);
+    
+    code.setEntrypoints(WTFMove(entrypoints));
+    code.resetReachability();
+}
+
+} } } // namespace JSC::B3::Air
+
+#endif // ENABLE(B3_JIT)
+
+