Refactor Host expression to MemorySize and MemoryGrow (#3137)

Aligns the internal representations of `memory.size` and `memory.grow` with other more recent memory instructions by removing the legacy `Host` expression class and adding separate expression classes for `MemorySize` and `MemoryGrow`. Simplifies related APIs, but is also a breaking API change.

1 files changed, 14 insertions, 23 deletions

diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index 15ab97098..916615e07 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -1430,16 +1430,8 @@ struct PrintExpressionContents
   }
   void visitDrop(Drop* curr) { printMedium(o, "drop"); }
   void visitReturn(Return* curr) { printMedium(o, "return"); }
-  void visitHost(Host* curr) {
-    switch (curr->op) {
-      case MemorySize:
-        printMedium(o, "memory.size");
-        break;
-      case MemoryGrow:
-        printMedium(o, "memory.grow");
-        break;
-    }
-  }
+  void visitMemorySize(MemorySize* curr) { printMedium(o, "memory.size"); }
+  void visitMemoryGrow(MemoryGrow* curr) { printMedium(o, "memory.grow"); }
   void visitRefNull(RefNull* curr) {
     printMedium(o, "ref.null ");
     o << curr->type.getHeapType();
@@ -1577,7 +1569,9 @@ struct PrintSExpression : public OverriddenVisitor<PrintSExpression> {
     o << ')';
   }
   void printFullLine(Expression* expression) {
-    !minify && doIndent(o, indent);
+    if (!minify) {
+      doIndent(o, indent);
+    }
     if (full) {
       o << "[" << expression->type << "] ";
     }
@@ -1945,20 +1939,17 @@ struct PrintSExpression : public OverriddenVisitor<PrintSExpression> {
     printFullLine(curr->value);
     decIndent();
   }
-  void visitHost(Host* curr) {
+  void visitMemorySize(MemorySize* curr) {
     o << '(';
     PrintExpressionContents(currFunction, o).visit(curr);
-    switch (curr->op) {
-      case MemoryGrow: {
-        incIndent();
-        printFullLine(curr->operands[0]);
-        decIndent();
-        break;
-      }
-      case MemorySize: {
-        o << ')';
-      }
-    }
+    o << ')';
+  }
+  void visitMemoryGrow(MemoryGrow* curr) {
+    o << '(';
+    PrintExpressionContents(currFunction, o).visit(curr);
+    incIndent();
+    printFullLine(curr->delta);
+    decIndent();
   }
   void visitRefNull(RefNull* curr) {
     o << '(';