1 files changed, 65 insertions, 0 deletions
diff --git a/vm/compiler/codegen/arm/GlobalOptimizations.cpp b/vm/compiler/codegen/arm/GlobalOptimizations.cpp
new file mode 100644
index 000000000..e52bd8a49
--- /dev/null
+++ b/vm/compiler/codegen/arm/GlobalOptimizations.cpp
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2009 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.
+ */
+
+#include "Dalvik.h"
+#include "vm/compiler/CompilerInternals.h"
+#include "ArmLIR.h"
+
+/*
+ * Identify unconditional branches that jump to the immediate successor of the
+ * branch itself.
+ */
+static void applyRedundantBranchElimination(CompilationUnit *cUnit)
+{
+    ArmLIR *thisLIR;
+
+    for (thisLIR = (ArmLIR *) cUnit->firstLIRInsn;
+         thisLIR != (ArmLIR *) cUnit->lastLIRInsn;
+         thisLIR = NEXT_LIR(thisLIR)) {
+
+        /* Branch to the next instruction */
+        if (thisLIR->opcode == kThumbBUncond) {
+            ArmLIR *nextLIR = thisLIR;
+
+            while (true) {
+                nextLIR = NEXT_LIR(nextLIR);
+
+                /*
+                 * Is the branch target the next instruction?
+                 */
+                if (nextLIR == (ArmLIR *) thisLIR->generic.target) {
+                    thisLIR->flags.isNop = true;
+                    break;
+                }
+
+                /*
+                 * Found real useful stuff between the branch and the target.
+                 * Need to explicitly check the lastLIRInsn here since with
+                 * method-based JIT the branch might be the last real
+                 * instruction.
+                 */
+                if (!isPseudoOpcode(nextLIR->opcode) ||
+                    (nextLIR = (ArmLIR *) cUnit->lastLIRInsn))
+                    break;
+            }
+        }
+    }
+}
+
+void dvmCompilerApplyGlobalOptimizations(CompilationUnit *cUnit)
+{
+    applyRedundantBranchElimination(cUnit);
+}