X86: Use memory to do array range checks
Currently, an HBoundsCheck is fed by an HArrayLength, causing a load of
the array length, followed by a register compare.
Avoid the load when we can by comparing directly with the array length
in memory. Implement this by marking the HArrayLength as 'emitted at
use site', and then generating the code in the HBoundsCheck.
Only do this replacement when we are the only user of the ArrayLength
and it isn't visible to the environment.
Handle the special case where the array is 'null' and where an implicit
null check can't be eliminated.
This code moves the load of the length to the slow code for the failed
check, which is what we want.
Test: 609-checker-x86-bounds-check
Change-Id: I9cdb183301e048234bb0ffeda940eedcf4a655bd
Signed-off-by: Mark Mendell <mark.p.mendell@intel.com>
diff --git a/compiler/optimizing/x86_memory_gen.h b/compiler/optimizing/x86_memory_gen.h
new file mode 100644
index 0000000..7e88681
--- /dev/null
+++ b/compiler/optimizing/x86_memory_gen.h
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_COMPILER_OPTIMIZING_X86_MEMORY_GEN_H_
+#define ART_COMPILER_OPTIMIZING_X86_MEMORY_GEN_H_
+
+#include "nodes.h"
+#include "optimization.h"
+
+namespace art {
+class CodeGenerator;
+
+namespace x86 {
+
+class X86MemoryOperandGeneration : public HOptimization {
+ public:
+ X86MemoryOperandGeneration(HGraph* graph,
+ OptimizingCompilerStats* stats,
+ CodeGenerator* codegen);
+
+ void Run() OVERRIDE;
+
+ static constexpr const char* kX86MemoryOperandGenerationPassName =
+ "x86_memory_operand_generation";
+
+ private:
+ bool do_implicit_null_checks_;
+};
+
+} // namespace x86
+} // namespace art
+
+#endif // ART_COMPILER_OPTIMIZING_X86_MEMORY_GEN_H_