1 files changed, 24 insertions, 11 deletions

diff --git a/src/passes/StringLowering.cpp b/src/passes/StringLowering.cpp
index df2d66860..dd7428546 100644
--- a/src/passes/StringLowering.cpp
+++ b/src/passes/StringLowering.cpp
@@ -189,6 +189,13 @@ struct StringGathering : public Pass {
 };
 
 struct StringLowering : public StringGathering {
+  // If true, then encode well-formed strings as (import "'" "string...")
+  // instead of emitting them into the JSON custom section.
+  bool useMagicImports;
+
+  StringLowering(bool useMagicImports = false)
+    : useMagicImports(useMagicImports) {}
+
   void run(Module* module) override {
     if (!module->features.has(FeatureSet::Strings)) {
       return;
@@ -217,25 +224,30 @@ struct StringLowering : public StringGathering {
   }
 
   void makeImports(Module* module) {
-    Index importIndex = 0;
+    Index jsonImportIndex = 0;
     std::stringstream json;
     json << '[';
     bool first = true;
-    std::vector<Name> importedStrings;
     for (auto& global : module->globals) {
       if (global->init) {
         if (auto* c = global->init->dynCast<StringConst>()) {
-          global->module = "string.const";
-          global->base = std::to_string(importIndex);
-          importIndex++;
-          global->init = nullptr;
-
-          if (first) {
-            first = false;
+          std::stringstream utf8;
+          if (useMagicImports &&
+              String::convertUTF16ToUTF8(utf8, c->string.str)) {
+            global->module = "'";
+            global->base = Name(utf8.str());
           } else {
-            json << ',';
+            global->module = "string.const";
+            global->base = std::to_string(jsonImportIndex);
+            if (first) {
+              first = false;
+            } else {
+              json << ',';
+            }
+            String::printEscapedJSON(json, c->string.str);
+            jsonImportIndex++;
           }
-          String::printEscapedJSON(json, c->string.str);
+          global->init = nullptr;
         }
       }
     }
@@ -516,5 +528,6 @@ struct StringLowering : public StringGathering {
 
 Pass* createStringGatheringPass() { return new StringGathering(); }
 Pass* createStringLoweringPass() { return new StringLowering(); }
+Pass* createStringLoweringMagicImportPass() { return new StringLowering(true); }
 
 } // namespace wasm