3 files changed, 82 insertions, 9 deletions

diff --git a/src/passes/Bysyncify.cpp b/src/passes/Bysyncify.cpp
index 5e2f73e5c..cb85f0b0a 100644
--- a/src/passes/Bysyncify.cpp
+++ b/src/passes/Bysyncify.cpp
@@ -185,6 +185,7 @@
 //      Each module.base in that comma-separated list will be considered to
 //      be an import that can unwind/rewind, and all others are assumed not to
 //      (aside from the bysyncify.* imports, which are always assumed to).
+//      Each entry can end in a '*' in which case it is matched as a prefix.
 //
 //   --pass-arg=bysyncify-ignore-imports
 //
@@ -206,6 +207,7 @@
 #include "ir/module-utils.h"
 #include "ir/utils.h"
 #include "pass.h"
+#include "support/string.h"
 #include "support/unique_deferring_queue.h"
 #include "wasm-builder.h"
 #include "wasm.h"
@@ -960,14 +962,11 @@ struct Bysyncify : public Pass {
     // Find which things can change the state.
     auto stateChangingImports =
       runner->options.getArgumentOrDefault("bysyncify-imports", "");
-    std::string separator = ",";
     auto ignoreImports =
       runner->options.getArgumentOrDefault("bysyncify-ignore-imports", "");
     bool allImportsCanChangeState =
       stateChangingImports == "" && ignoreImports == "";
-    if (!allImportsCanChangeState) {
-      stateChangingImports = separator + stateChangingImports + separator;
-    }
+    String::Split listedImports(stateChangingImports, ",");
     auto ignoreIndirect =
       runner->options.getArgumentOrDefault("bysyncify-ignore-indirect", "");
 
@@ -978,8 +977,13 @@ struct Bysyncify : public Pass {
         if (allImportsCanChangeState) {
           return true;
         }
-        std::string full = separator + module.str + '.' + base.str + separator;
-        return stateChangingImports.find(full) != std::string::npos;
+        std::string full = std::string(module.str) + '.' + base.str;
+        for (auto& listedImport : listedImports) {
+          if (String::wildcardMatch(listedImport, full)) {
+            return true;
+          }
+        }
+        return false;
       },
       ignoreIndirect == "");
 
diff --git a/src/support/name.h b/src/support/name.h
index 6f17c3ebf..b6242aabc 100644
--- a/src/support/name.h
+++ b/src/support/name.h
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef wasm_support_string_h
-#define wasm_support_string_h
+#ifndef wasm_support_name_h
+#define wasm_support_name_h
 
 #include <cstring>
 
@@ -65,4 +65,4 @@ template<> struct hash<wasm::Name> : hash<cashew::IString> {};
 
 } // namespace std
 
-#endif // wasm_support_string_h
+#endif // wasm_support_name_h
diff --git a/src/support/string.h b/src/support/string.h
new file mode 100644
index 000000000..c8a8cb445
--- /dev/null
+++ b/src/support/string.h
@@ -0,0 +1,69 @@
+/*
+ * Copyright 2019 WebAssembly Community Group participants
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+//
+// String helpers.
+//
+
+#ifndef wasm_support_string_h
+#define wasm_support_string_h
+
+#include <string>
+#include <vector>
+
+namespace wasm {
+
+namespace String {
+
+// Creates a vector of the split parts of a string, by a delimiter.
+class Split : public std::vector<std::string> {
+public:
+  Split(const std::string& input, const std::string& delim) {
+    size_t lastEnd = 0;
+    while (lastEnd < input.size()) {
+      auto nextDelim = input.find(delim, lastEnd);
+      if (nextDelim == std::string::npos) {
+        nextDelim = input.size();
+      }
+      (*this).push_back(input.substr(lastEnd, nextDelim - lastEnd));
+      lastEnd = nextDelim + delim.size();
+    }
+  }
+};
+
+// Does a simple wildcard match between a pattern and a value. Currently
+// supports a '*' at the end of the pattern.
+inline bool wildcardMatch(const std::string& pattern,
+                          const std::string& value) {
+  for (size_t i = 0; i < pattern.size(); i++) {
+    if (i >= value.size()) {
+      return false;
+    }
+    if (pattern[i] == '*') {
+      return true;
+    }
+    if (pattern[i] != value[i]) {
+      return false;
+    }
+  }
+  return value.size() == pattern.size();
+}
+
+} // namespace String
+
+} // namespace wasm
+
+#endif // wasm_support_string_h