Unify imported and non-imported things (#1678)

Fixes #1649

This moves us to a single object for functions, which can be imported or nor, and likewise for globals (as a result, GetGlobals do not need to check if the global is imported or not, etc.). All imported things now inherit from Importable, which has the module and base of the import, and if they are set then it is an import.

For convenient iteration, there are a few helpers like

ModuleUtils::iterDefinedGlobals(wasm, [&](Global* global) {
  .. use global ..
});

as often iteration only cares about imported or defined (non-imported) things.

1 files changed, 55 insertions, 6 deletions

diff --git a/src/ir/import-utils.h b/src/ir/import-utils.h
index f3f01c266..5f7bbc9ed 100644
--- a/src/ir/import-utils.h
+++ b/src/ir/import-utils.h
@@ -22,17 +22,66 @@
 
 namespace wasm {
 
-namespace ImportUtils {
-  // find an import by the module.base that is being imported.
-  // return the internal name
-  inline Import* getImport(Module& wasm, Name module, Name base) {
-    for (auto& import : wasm.imports) {
+// Collects info on imports, into a form convenient for summarizing
+// and searching.
+struct ImportInfo {
+  Module& wasm;
+
+  std::vector<Global*> importedGlobals;
+  std::vector<Function*> importedFunctions;
+
+  ImportInfo(Module& wasm) : wasm(wasm) {
+    for (auto& import : wasm.globals) {
+      if (import->imported()) {
+        importedGlobals.push_back(import.get());
+      }
+    }
+    for (auto& import : wasm.functions) {
+      if (import->imported()) {
+        importedFunctions.push_back(import.get());
+      }
+    }
+  }
+
+  Global* getImportedGlobal(Name module, Name base) {
+    for (auto* import : importedGlobals) {
+      if (import->module == module && import->base == base) {
+        return import;
+      }
+    }
+    return nullptr;
+  }
+
+  Function* getImportedFunction(Name module, Name base) {
+    for (auto* import : importedFunctions) {
       if (import->module == module && import->base == base) {
-        return import.get();
+        return import;
       }
     }
     return nullptr;
   }
+
+  Index getNumImportedGlobals() {
+    return importedGlobals.size();
+  }
+
+  Index getNumImportedFunctions() {
+    return importedFunctions.size();
+  }
+
+  Index getNumImports() {
+    return getNumImportedGlobals() + getNumImportedFunctions() +
+           (wasm.memory.imported() ? 1 : 0) +
+           (wasm.table.imported() ? 1 : 0);
+  }
+
+  Index getNumDefinedGlobals() {
+    return wasm.globals.size() - getNumImportedGlobals();
+  }
+
+  Index getNumDefinedFunctions() {
+    return wasm.functions.size() - getNumImportedFunctions();
+  }
 };
 
 } // namespace wasm