Move type utility classes to type-utils.h (NFC)

This renames type-updating.h to type-utils.h and moves TypeSeeker class,
which is currently only used in wasm.cpp, to that file too. I plan to
use this elsewhere in WebAssembly#2451 and I think making this a separate PR makes
things easier to review.

src/ir/type-updating.h → src/ir/type-utils.h

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef wasm_ir_type_updating_h
-#define wasm_ir_type_updating_h
+#ifndef wasm_ir_type_utils_h
+#define wasm_ir_type_utils_h
 
 #include "wasm-traversal.h"
 
@@ -316,6 +316,66 @@ struct TypeUpdater
   }
 };
 
+// core AST type checking
+struct TypeSeeker : public PostWalker<TypeSeeker> {
+  Expression* target; // look for this one
+  Name targetName;
+  std::vector<Type> types;
+
+  TypeSeeker(Expression* target, Name targetName)
+    : target(target), targetName(targetName) {
+    Expression* temp = target;
+    walk(temp);
+  }
+
+  void visitBreak(Break* curr) {
+    if (curr->name == targetName) {
+      types.push_back(curr->value ? curr->value->type : none);
+    }
+  }
+
+  void visitSwitch(Switch* curr) {
+    for (auto name : curr->targets) {
+      if (name == targetName) {
+        types.push_back(curr->value ? curr->value->type : none);
+      }
+    }
+    if (curr->default_ == targetName) {
+      types.push_back(curr->value ? curr->value->type : none);
+    }
+  }
+
+  void visitBrOnExn(BrOnExn* curr) {
+    if (curr->name == targetName) {
+      types.push_back(curr->sent);
+    }
+  }
+
+  void visitBlock(Block* curr) {
+    if (curr == target) {
+      if (curr->list.size() > 0) {
+        types.push_back(curr->list.back()->type);
+      } else {
+        types.push_back(none);
+      }
+    } else if (curr->name == targetName) {
+      // ignore all breaks til now, they were captured by someone with the same
+      // name
+      types.clear();
+    }
+  }
+
+  void visitLoop(Loop* curr) {
+    if (curr == target) {
+      types.push_back(curr->body->type);
+    } else if (curr->name == targetName) {
+      // ignore all breaks til now, they were captured by someone with the same
+      // name
+      types.clear();
+    }
+  }
+};
+
 } // namespace wasm
 
-#endif // wasm_ir_type_updating_h
+#endif // wasm_ir_type_utils_h

src/passes/DeadCodeElimination.cpp

@@ -30,7 +30,7 @@
 
 #include <ir/block-utils.h>
 #include <ir/branch-utils.h>
-#include <ir/type-updating.h>
+#include <ir/type-utils.h>
 #include <pass.h>
 #include <vector>
 #include <wasm-builder.h>

src/passes/Vacuum.cpp

@@ -21,7 +21,7 @@
 #include <ir/block-utils.h>
 #include <ir/effects.h>
 #include <ir/literal-utils.h>
-#include <ir/type-updating.h>
+#include <ir/type-utils.h>
 #include <ir/utils.h>
 #include <pass.h>
 #include <wasm-builder.h>

src/wasm/wasm.cpp

@@ -16,6 +16,7 @@
 
 #include "wasm.h"
 #include "ir/branch-utils.h"
+#include "ir/type-utils.h"
 #include "wasm-traversal.h"
 
 namespace wasm {
@@ -187,67 +188,6 @@ const char* getExpressionName(Expression* curr) {
   WASM_UNREACHABLE();
 }
 
-// core AST type checking
-
-struct TypeSeeker : public PostWalker<TypeSeeker> {
-  Expression* target; // look for this one
-  Name targetName;
-  std::vector<Type> types;
-
-  TypeSeeker(Expression* target, Name targetName)
-    : target(target), targetName(targetName) {
-    Expression* temp = target;
-    walk(temp);
-  }
-
-  void visitBreak(Break* curr) {
-    if (curr->name == targetName) {
-      types.push_back(curr->value ? curr->value->type : none);
-    }
-  }
-
-  void visitSwitch(Switch* curr) {
-    for (auto name : curr->targets) {
-      if (name == targetName) {
-        types.push_back(curr->value ? curr->value->type : none);
-      }
-    }
-    if (curr->default_ == targetName) {
-      types.push_back(curr->value ? curr->value->type : none);
-    }
-  }
-
-  void visitBrOnExn(BrOnExn* curr) {
-    if (curr->name == targetName) {
-      types.push_back(curr->sent);
-    }
-  }
-
-  void visitBlock(Block* curr) {
-    if (curr == target) {
-      if (curr->list.size() > 0) {
-        types.push_back(curr->list.back()->type);
-      } else {
-        types.push_back(none);
-      }
-    } else if (curr->name == targetName) {
-      // ignore all breaks til now, they were captured by someone with the same
-      // name
-      types.clear();
-    }
-  }
-
-  void visitLoop(Loop* curr) {
-    if (curr == target) {
-      types.push_back(curr->body->type);
-    } else if (curr->name == targetName) {
-      // ignore all breaks til now, they were captured by someone with the same
-      // name
-      types.clear();
-    }
-  }
-};
-
 static Type mergeTypes(std::vector<Type>& types) {
   Type type = unreachable;
   for (auto other : types) {