[Parser] Match legacy parser block naming (#6504)

To reduce the size of the test output diff when switching to the new text
parser, update it to generate the same block names as the legacy parser.

3 files changed, 17 insertions, 7 deletions

diff --git a/src/ir/names.h b/src/ir/names.h
index e2a168940..c10b70b52 100644
--- a/src/ir/names.h
+++ b/src/ir/names.h
@@ -49,12 +49,14 @@ inline void ensureNames(Function* func) {
 // name will begin there. This can be used to avoid trying the same 0,1,2,..
 // etc. names each time (which could lead to quadratic behavior in certain
 // cases).
-inline Name
-getValidName(Name root, std::function<bool(Name)> check, Index hint = 0) {
+inline Name getValidName(Name root,
+                         std::function<bool(Name)> check,
+                         Index hint = 0,
+                         std::string separator = "_") {
   if (check(root)) {
     return root;
   }
-  auto prefixed = std::string(root.str) + '_';
+  auto prefixed = std::string(root.str) + separator;
   Index num = hint;
   while (1) {
     auto name = prefixed + std::to_string(num);
diff --git a/src/wasm-ir-builder.h b/src/wasm-ir-builder.h
index 3b6588e86..5803f0c61 100644
--- a/src/wasm-ir-builder.h
+++ b/src/wasm-ir-builder.h
@@ -461,9 +461,13 @@ private:
   std::unordered_map<Name, std::vector<Index>> labelDepths;
 
   Name makeFresh(Name label) {
-    return Names::getValidName(label, [&](Name candidate) {
-      return labelDepths.insert({candidate, {}}).second;
-    });
+    return Names::getValidName(
+      label,
+      [&](Name candidate) {
+        return labelDepths.insert({candidate, {}}).second;
+      },
+      0,
+      "");
   }
 
   void pushScope(ScopeCtx scope) {
diff --git a/src/wasm/wasm-ir-builder.cpp b/src/wasm/wasm-ir-builder.cpp
index bee858435..78ce07f8d 100644
--- a/src/wasm/wasm-ir-builder.cpp
+++ b/src/wasm/wasm-ir-builder.cpp
@@ -1035,7 +1035,11 @@ Result<Name> IRBuilder::getLabelName(Index label) {
   auto& scopeLabel = (*scope)->label;
   if (!scopeLabel) {
     // The scope does not already have a name, so we need to create one.
-    scopeLabel = makeFresh("label");
+    if ((*scope)->getBlock()) {
+      scopeLabel = makeFresh("block");
+    } else {
+      scopeLabel = makeFresh("label");
+    }
   }
   (*scope)->labelUsed = true;
   return scopeLabel;