Consolidate printing of function signatures (#7073)

There were previously two separate code paths for printing function
signatures, one for imported functions and one for declared functions.
The only intended difference was that parameter names were printed for
declared functions but not for imported functions.

Reduce duplication by consolidating the code paths, and add support for
printing names for imported function parameters that have them. Also fix
a bug where empty names were printed as `$` rather than the correct
`$""`.

2 files changed, 44 insertions, 57 deletions

diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index 854ea0b5b..5a5d01299 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -382,7 +382,7 @@ struct PrintSExpression : public UnifiedExpressionVisitor<PrintSExpression> {
   }
 
   // Module-level visitors
-  void handleSignature(HeapType curr, Name name = Name());
+  void handleSignature(Function* curr, bool printImplicitNames = false);
   void visitExport(Export* curr);
   void emitImportHeader(Importable* curr);
   void visitGlobal(Global* curr);
@@ -2883,41 +2883,51 @@ static bool requiresExplicitFuncType(HeapType type) {
   return type.isOpen() || type.isShared() || type.getRecGroup().size() > 1;
 }
 
-void PrintSExpression::handleSignature(HeapType curr, Name name) {
-  Signature sig = curr.getSignature();
-  o << "(func";
-  if (name.is()) {
-    o << ' ';
-    name.print(o);
-    if ((currModule && currModule->features.hasGC()) ||
-        requiresExplicitFuncType(curr)) {
-      o << " (type ";
-      printHeapType(curr) << ')';
-    }
+void PrintSExpression::handleSignature(Function* curr,
+                                       bool printImplicitNames) {
+  o << '(';
+  printMajor(o, "func ");
+  curr->name.print(o);
+  if ((currModule && currModule->features.hasGC()) ||
+      requiresExplicitFuncType(curr->type)) {
+    o << " (type ";
+    printHeapType(curr->type) << ')';
   }
-  if (sig.params.size() > 0) {
-    o << maybeSpace;
-    o << "(param ";
-    auto sep = "";
-    for (auto type : sig.params) {
-      o << sep;
-      printType(type);
-      sep = " ";
+  bool inParam = false;
+  Index i = 0;
+  for (const auto& param : curr->getParams()) {
+    auto hasName = printImplicitNames || curr->hasLocalName(i);
+    if (hasName && inParam) {
+      o << ')' << maybeSpace;
+      inParam = false;
+    } else if (inParam) {
+      o << ' ';
+    } else {
+      o << maybeSpace;
+    }
+    if (!inParam) {
+      o << '(';
+      printMinor(o, "param ");
+      inParam = true;
+    }
+    if (hasName) {
+      printLocal(i, currFunction, o);
+      o << ' ';
+    }
+    printType(param);
+    if (hasName) {
+      o << ')';
+      inParam = false;
     }
+    ++i;
+  }
+  if (inParam) {
     o << ')';
   }
-  if (sig.results.size() > 0) {
+  if (curr->getResults() != Type::none) {
     o << maybeSpace;
-    o << "(result ";
-    auto sep = "";
-    for (auto type : sig.results) {
-      o << sep;
-      printType(type);
-      sep = " ";
-    }
-    o << ')';
+    printResultType(curr->getResults());
   }
-  o << ")";
 }
 
 void PrintSExpression::visitExport(Export* curr) {
@@ -3014,8 +3024,8 @@ void PrintSExpression::visitImportedFunction(Function* curr) {
   lastPrintedLocation = std::nullopt;
   o << '(';
   emitImportHeader(curr);
-  handleSignature(curr->type, curr->name);
-  o << ')';
+  handleSignature(curr);
+  o << "))";
   o << maybeNewLine;
 }
 
@@ -3027,30 +3037,7 @@ void PrintSExpression::visitDefinedFunction(Function* curr) {
   if (currFunction->prologLocation.size()) {
     printDebugLocation(*currFunction->prologLocation.begin());
   }
-  o << '(';
-  printMajor(o, "func ");
-  curr->name.print(o);
-  if ((currModule && currModule->features.hasGC()) ||
-      requiresExplicitFuncType(curr->type)) {
-    o << " (type ";
-    printHeapType(curr->type) << ')';
-  }
-  if (curr->getParams().size() > 0) {
-    Index i = 0;
-    for (const auto& param : curr->getParams()) {
-      o << maybeSpace;
-      o << '(';
-      printMinor(o, "param ");
-      printLocal(i, currFunction, o);
-      o << ' ';
-      printType(param) << ')';
-      ++i;
-    }
-  }
-  if (curr->getResults() != Type::none) {
-    o << maybeSpace;
-    printResultType(curr->getResults());
-  }
+  handleSignature(curr, true);
   incIndent();
   for (size_t i = curr->getVarIndexBase(); i < curr->getNumLocals(); i++) {
     doIndent(o, indent);
diff --git a/src/support/name.cpp b/src/support/name.cpp
index 4e53e3f83..4c599defc 100644
--- a/src/support/name.cpp
+++ b/src/support/name.cpp
@@ -46,7 +46,7 @@ std::ostream& Name::print(std::ostream& o) const {
   // TODO: This is not spec-compliant since the spec does not yet support
   // quoted identifiers and has a limited set of valid idchars.
   o << '$';
-  if (std::all_of(str.begin(), str.end(), isIDChar)) {
+  if (size() >= 1 && std::all_of(str.begin(), str.end(), isIDChar)) {
     return o << str;
   } else {
     return String::printEscaped(o, str);