Refactor Features code (#1848)

Add features.h which centralizes all the feature detection code. (I'll need this in another place than the validator which is where it was til now.)

3 files changed, 183 insertions, 4 deletions

diff --git a/src/ir/features.h b/src/ir/features.h
new file mode 100644
index 000000000..ed7fb6ff5
--- /dev/null
+++ b/src/ir/features.h
@@ -0,0 +1,175 @@
+/*
+ * Copyright 2018 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.
+ */
+
+#ifndef wasm_ir_features_h
+#define wasm_ir_features_h
+
+#include <wasm.h>
+#include <wasm-binary.h>
+#include <wasm-traversal.h>
+#include <ir/iteration.h>
+
+namespace wasm {
+
+namespace Features {
+
+inline FeatureSet get(UnaryOp op) {
+  FeatureSet ret;
+  switch (op) {
+    case TruncSatSFloat32ToInt32:
+    case TruncSatUFloat32ToInt32:
+    case TruncSatSFloat64ToInt32:
+    case TruncSatUFloat64ToInt32:
+    case TruncSatSFloat32ToInt64:
+    case TruncSatUFloat32ToInt64:
+    case TruncSatSFloat64ToInt64:
+    case TruncSatUFloat64ToInt64: {
+      ret.setTruncSat();
+      break;
+    }
+    case SplatVecI8x16:
+    case SplatVecI16x8:
+    case SplatVecI32x4:
+    case SplatVecI64x2:
+    case SplatVecF32x4:
+    case SplatVecF64x2:
+    case NotVec128:
+    case NegVecI8x16:
+    case AnyTrueVecI8x16:
+    case AllTrueVecI8x16:
+    case NegVecI16x8:
+    case AnyTrueVecI16x8:
+    case AllTrueVecI16x8:
+    case NegVecI32x4:
+    case AnyTrueVecI32x4:
+    case AllTrueVecI32x4:
+    case NegVecI64x2:
+    case AnyTrueVecI64x2:
+    case AllTrueVecI64x2:
+    case AbsVecF32x4:
+    case NegVecF32x4:
+    case SqrtVecF32x4:
+    case AbsVecF64x2:
+    case NegVecF64x2:
+    case SqrtVecF64x2:
+    case TruncSatSVecF32x4ToVecI32x4:
+    case TruncSatUVecF32x4ToVecI32x4:
+    case TruncSatSVecF64x2ToVecI64x2:
+    case TruncSatUVecF64x2ToVecI64x2:
+    case ConvertSVecI32x4ToVecF32x4:
+    case ConvertUVecI32x4ToVecF32x4:
+    case ConvertSVecI64x2ToVecF64x2:
+    case ConvertUVecI64x2ToVecF64x2: {
+      ret.setSIMD();
+      break;
+    }
+    default: {}
+  }
+  return ret;
+}
+
+inline FeatureSet get(BinaryOp op) {
+  FeatureSet ret;
+  switch (op) {
+    case EqVecI8x16:
+    case NeVecI8x16:
+    case LtSVecI8x16:
+    case LtUVecI8x16:
+    case GtSVecI8x16:
+    case GtUVecI8x16:
+    case LeSVecI8x16:
+    case LeUVecI8x16:
+    case GeSVecI8x16:
+    case GeUVecI8x16:
+    case EqVecI16x8:
+    case NeVecI16x8:
+    case LtSVecI16x8:
+    case LtUVecI16x8:
+    case GtSVecI16x8:
+    case GtUVecI16x8:
+    case LeSVecI16x8:
+    case LeUVecI16x8:
+    case GeSVecI16x8:
+    case GeUVecI16x8:
+    case EqVecI32x4:
+    case NeVecI32x4:
+    case LtSVecI32x4:
+    case LtUVecI32x4:
+    case GtSVecI32x4:
+    case GtUVecI32x4:
+    case LeSVecI32x4:
+    case LeUVecI32x4:
+    case GeSVecI32x4:
+    case GeUVecI32x4:
+    case EqVecF32x4:
+    case NeVecF32x4:
+    case LtVecF32x4:
+    case GtVecF32x4:
+    case LeVecF32x4:
+    case GeVecF32x4:
+    case EqVecF64x2:
+    case NeVecF64x2:
+    case LtVecF64x2:
+    case GtVecF64x2:
+    case LeVecF64x2:
+    case GeVecF64x2:
+    case AndVec128:
+    case OrVec128:
+    case XorVec128:
+    case AddVecI8x16:
+    case AddSatSVecI8x16:
+    case AddSatUVecI8x16:
+    case SubVecI8x16:
+    case SubSatSVecI8x16:
+    case SubSatUVecI8x16:
+    case MulVecI8x16:
+    case AddVecI16x8:
+    case AddSatSVecI16x8:
+    case AddSatUVecI16x8:
+    case SubVecI16x8:
+    case SubSatSVecI16x8:
+    case SubSatUVecI16x8:
+    case MulVecI16x8:
+    case AddVecI32x4:
+    case SubVecI32x4:
+    case MulVecI32x4:
+    case AddVecI64x2:
+    case SubVecI64x2:
+    case AddVecF32x4:
+    case SubVecF32x4:
+    case MulVecF32x4:
+    case DivVecF32x4:
+    case MinVecF32x4:
+    case MaxVecF32x4:
+    case AddVecF64x2:
+    case SubVecF64x2:
+    case MulVecF64x2:
+    case DivVecF64x2:
+    case MinVecF64x2:
+    case MaxVecF64x2: {
+      ret.setSIMD();
+      break;
+    }
+    default: {}
+  }
+  return ret;
+}
+
+} // namespace Features
+
+} // namespace wasm
+
+#endif // wasm_ir_features_h
diff --git a/src/wasm.h b/src/wasm.h
index bcdc30dab..27a302d3c 100644
--- a/src/wasm.h
+++ b/src/wasm.h
@@ -67,7 +67,11 @@ struct FeatureSet {
   void setSIMD(bool v = true) { set(SIMD, v); }
   void setAll(bool v = true) { features = v ? All : MVP; }
 
- private:
+  bool operator<=(const FeatureSet& other) {
+    return !(features & ~other.features);
+  }
+
+private:
   uint32_t features;
 };
 
diff --git a/src/wasm/wasm-validator.cpp b/src/wasm/wasm-validator.cpp
index d11d02353..b018db2d0 100644
--- a/src/wasm/wasm-validator.cpp
+++ b/src/wasm/wasm-validator.cpp
@@ -24,10 +24,10 @@
 #include "wasm-validator.h"
 #include "ir/utils.h"
 #include "ir/branch-utils.h"
+#include "ir/features.h"
 #include "ir/module-utils.h"
 #include "support/colors.h"
 
-
 namespace wasm {
 
 // Print anything that can be streamed to an ostream
@@ -823,6 +823,7 @@ void FunctionValidator::visitBinary(Binary* curr) {
     }
     case InvalidBinary: WASM_UNREACHABLE();
   }
+  shouldBeTrue(Features::get(curr->op) <= info.features, curr, "all used features should be allowed");
 }
 
 void FunctionValidator::visitUnary(Unary* curr) {
@@ -897,7 +898,6 @@ void FunctionValidator::visitUnary(Unary* curr) {
     case TruncSatSFloat32ToInt64:
     case TruncSatUFloat32ToInt32:
     case TruncSatUFloat32ToInt64: {
-      shouldBeTrue(info.features.hasTruncSat(), curr, "nontrapping float-to-int conversions are disabled");
       shouldBeEqual(curr->value->type, f32, curr, "trunc type must be correct");
       break;
     }
@@ -912,7 +912,6 @@ void FunctionValidator::visitUnary(Unary* curr) {
     case TruncSatSFloat64ToInt64:
     case TruncSatUFloat64ToInt32:
     case TruncSatUFloat64ToInt64: {
-      shouldBeTrue(info.features.hasTruncSat(), curr, "nontrapping float-to-int conversions are disabled");
       shouldBeEqual(curr->value->type, f64, curr, "trunc type must be correct");
       break;
     }
@@ -1007,6 +1006,7 @@ void FunctionValidator::visitUnary(Unary* curr) {
       break;
     case InvalidUnary: WASM_UNREACHABLE();
   }
+  shouldBeTrue(Features::get(curr->op) <= info.features, curr, "all used features should be allowed");
 }
 
 void FunctionValidator::visitSelect(Select* curr) {