SSA pass (#1049)

 * Add SSA pass which ensures a single assign for each local, except for merged locals where we ensure exactly a single assign from one of the paths leading to that use

 * Also add InstrumentLocals pass, useful for debugging locals (similar to InstrumentMemory but for locals)

 * Fix a PickLoadSigns bug with tees not being ignored, which was not noticed until now because we ran it on flatter output by default, but the ssa pass uncovered the bug

1 files changed, 55 insertions, 0 deletions

diff --git a/src/support/permutations.h b/src/support/permutations.h
new file mode 100644
index 000000000..214063058
--- /dev/null
+++ b/src/support/permutations.h
@@ -0,0 +1,55 @@
+/*
+ * Copyright 2016 WebAssembly Community Group participants
+ *
+ * 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.
+ */
+
+// Utilities for operating on permutation vectors
+
+#ifndef wasm_support_permutations_h
+#define wasm_support_permutations_h
+
+#include "wasm.h"
+
+namespace wasm {
+
+inline std::vector<Index> makeIdentity(Index num) {
+  std::vector<Index> ret;
+  ret.resize(num);
+  for (Index i = 0; i < num; i++) {
+    ret[i] = i;
+  }
+  return ret;
+}
+
+inline void setIdentity(std::vector<Index>& ret) {
+  auto num = ret.size();
+  assert(num > 0); // must already be of the right size
+  for (Index i = 0; i < num; i++) {
+    ret[i] = i;
+  }
+}
+
+inline std::vector<Index> makeReversed(std::vector<Index>& original) {
+  std::vector<Index> ret;
+  auto num = original.size();
+  ret.resize(num);
+  for (Index i = 0; i < num; i++) {
+    ret[original[i]] = i;
+  }
+  return ret;
+}
+
+} // namespace wasm
+
+#endif // permutations