Check that module imports match their corresponding exports

stevenfontanella · stevenfontanella · commit cb635ed218f8 · 2025-12-11T18:45:25.000Z
diff --git a/scripts/test/shared.py b/scripts/test/shared.py
@@ -440,15 +440,14 @@ def get_tests(test_dir, extensions=[], recursive=False):
     'func.wast',    # Duplicate parameter names not properly rejected
     'global.wast',  # Fail to parse table
     'if.wast',      # Requires more precise unreachable validation
-    'imports.wast',  # Missing validation of missing function on instantiation
+    'imports.wast',  # Requires fixing handling of mutation to imported globals
     'proposals/threads/imports.wast',  # Missing memory type validation on instantiation
     'linking.wast',  # Missing function type validation on instantiation
     'proposals/threads/memory.wast',  # Missing memory type validation on instantiation
-    'memory64-imports.wast',  # Missing validation on instantiation
     'annotations.wast',  # String annotations IDs should be allowed
     'id.wast',       # Empty IDs should be disallowed
-    # Requires correct handling of tag imports from different instances of the same module,
-    # ref.null wast constants, and splitting for module instances
+    # Requires correct handling of tag imports from different instances of the same module
+    # and splitting for module instances
     'instance.wast',
     'table64.wast',   # Requires validations for table size
     'table_grow.wast',  # Incorrect table linking semantics in interpreter
@@ -473,12 +472,8 @@ def get_tests(test_dir, extensions=[], recursive=False):
     'type-rec.wast',  # Missing function type validation on instantiation
     'type-subtyping.wast',  # ShellExternalInterface::callTable does not handle subtyping
     'call_indirect.wast',   # Bug with 64-bit inline element segment parsing
-    'memory64.wast',        # Requires validations for memory size
-    'imports0.wast',        # Missing memory type validation on instantiation
-    'imports2.wast',        # Missing memory type validation on instantiation
-    'imports3.wast',        # Missing memory type validation on instantiation
-    'linking0.wast',        # Missing memory type validation on instantiation
-    'linking3.wast',        # Fatal error on missing table.
+    'memory64.wast',        # Requires validations on the max memory size
+    'imports3.wast',  # Requires better checking of exports from the special "spectest" module
     'i16x8_relaxed_q15mulr_s.wast',  # Requires wast `either` support
     'i32x4_relaxed_trunc.wast',      # Requires wast `either` support
     'i8x16_relaxed_swizzle.wast',    # Requires wast `either` support
diff --git a/src/shell-interface.h b/src/shell-interface.h
@@ -134,8 +134,10 @@ struct ShellExternalInterface : ModuleRunner::ExternalInterface {
       auto inst = getImportInstance(import);
       auto* exportedGlobal = inst->wasm.getExportOrNull(import->base);
       if (!exportedGlobal || exportedGlobal->kind != ExternalKind::Global) {
-        Fatal() << "importGlobals: unknown import: " << import->module.str
-                << "." << import->name.str;
+        trap((std::stringstream()
+              << "importGlobals: unknown import: " << import->module.str << "."
+              << import->name.str)
+               .str());
       }
       globals[import->name] = inst->globals[*exportedGlobal->getInternalName()];
     });
@@ -325,7 +327,9 @@ struct ShellExternalInterface : ModuleRunner::ExternalInterface {
     return true;
   }
 
-  void trap(const char* why) override {
+  void trap(const char* why) override { trap(std::string_view(why)); }
+
+  void trap(std::string_view why) override {
     std::cout << "[trap " << why << "]\n";
     throw TrapException();
   }
diff --git a/src/tools/wasm-shell.cpp b/src/tools/wasm-shell.cpp
@@ -176,6 +176,8 @@ struct Shell {
       // SIMD instructions.
       instance->setRelaxedBehavior(ModuleRunner::RelaxedBehavior::Execute);
       instance->instantiate();
+    } catch (const std::exception& e) {
+      return Err{std::string("failed to instantiate module: ") + e.what()};
     } catch (...) {
       return Err{"failed to instantiate module"};
     }
diff --git a/src/wasm-interpreter.h b/src/wasm-interpreter.h
@@ -29,6 +29,7 @@
 #define wasm_wasm_interpreter_h
 
 #include <cmath>
+#include <iomanip>
 #include <limits.h>
 #include <sstream>
 #include <variant>
@@ -86,7 +87,7 @@ class Flow {
   }
 
   Literals values;
-  Name breakTo; // if non-null, a break is going on
+  Name breakTo;              // if non-null, a break is going on
   Tag* suspendTag = nullptr; // if non-null, breakTo must be SUSPEND_FLOW, and
                              // this is the tag being suspended
 
@@ -2658,6 +2659,8 @@ class ExpressionRunner : public OverriddenVisitor<SubType, Flow> {
 
   virtual void trap(const char* why) { WASM_UNREACHABLE("unimp"); }
 
+  virtual void trap(std::string_view why) { WASM_UNREACHABLE("unimp"); }
+
   virtual void hostLimit(const char* why) { WASM_UNREACHABLE("unimp"); }
 
   virtual void throwException(const WasmException& exn) {
@@ -2937,6 +2940,7 @@ class ModuleRunnerBase : public ExpressionRunner<SubType> {
                            Index oldSize,
                            Index newSize) = 0;
     virtual void trap(const char* why) = 0;
+    virtual void trap(std::string_view why) { trap(std::string(why).c_str()); }
     virtual void hostLimit(const char* why) = 0;
     virtual void throwException(const WasmException& exn) = 0;
     // Get the Tag instance for a tag implemented in the host, that is, not
@@ -3178,6 +3182,8 @@ class ModuleRunnerBase : public ExpressionRunner<SubType> {
     // initialize the rest of the external interface
     externalInterface->init(wasm, *self());
 
+    validateImports();
+
     initializeTableContents();
     initializeMemoryContents();
 
@@ -3269,6 +3275,77 @@ class ModuleRunnerBase : public ExpressionRunner<SubType> {
     Name name;
   };
 
+  // Trap if the importable's export's kind doesn't match `kind`.
+  void validateImportKindMatches(ExternalKind kind,
+                                 const Importable& importable) {
+    auto it = linkedInstances.find(importable.module);
+    if (it == linkedInstances.end()) {
+      trap((std::stringstream()
+            << "Import module " << std::quoted(importable.module.toString())
+            << " doesn't exist.")
+             .str());
+    }
+    SubType* importedInstance = it->second.get();
+
+    Export* export_ = importedInstance->wasm.getExportOrNull(importable.base);
+
+    if (!export_) {
+      trap((std::stringstream()
+            << "Export " << importable.base << " doesn't exist.")
+             .str());
+    }
+    if (export_->kind != kind) {
+      trap("Exported kind doesn't match");
+    }
+  }
+
+  // Trap if types don't match between all imports and their corresponding
+  // exports. Imported memories and tables must also be a subtype of their
+  // export.
+  void validateImports() {
+    ModuleUtils::iterImportable(
+      wasm,
+      [this](ExternalKind kind,
+             std::variant<Function*, Memory*, Tag*, Global*, Table*> import) {
+        Importable* importable = std::visit(
+          [](const auto& import) -> Importable* { return import; }, import);
+
+        // These two modules are injected implicitly to tests. We won't find any
+        // import information for them.
+        if ((importable->module == "spectest" &&
+             importable->base.startsWith("print")) ||
+            importable->module == "fuzzing-support") {
+          return;
+        }
+
+        validateImportKindMatches(kind, *importable);
+
+        SubType* importedInstance =
+          linkedInstances.at(importable->module).get();
+        Export* export_ =
+          importedInstance->wasm.getExportOrNull(importable->base);
+
+        if (auto** memory = std::get_if<Memory*>(&import)) {
+          Memory exportedMemory =
+            *importedInstance->wasm.getMemory(*export_->getInternalName());
+          exportedMemory.initial =
+            importedInstance->getMemorySize(*export_->getInternalName());
+
+          if (!exportedMemory.isSubType(**memory)) {
+            trap("Imported memory isn't compatible.");
+          }
+        }
+
+        if (auto** table = std::get_if<Table*>(&import)) {
+          Table* exportedTable =
+            importedInstance->wasm.getTable(*export_->getInternalName());
+          if (!(*table)->isSubType(*exportedTable)) {
+            trap("Imported table isn't compatible");
+          }
+        }
+      });
+  }
+
   TableInstanceInfo getTableInstanceInfo(Name name) {
     auto* table = wasm.getTable(name);
     if (table->imported()) {
@@ -3326,12 +3403,16 @@ class ModuleRunnerBase : public ExpressionRunner<SubType> {
   };
 
   MemoryInstanceInfo getMemoryInstanceInfo(Name name) {
-    auto* memory = wasm.getMemory(name);
-    if (memory->imported()) {
-      auto& importedInstance = linkedInstances.at(memory->module);
-      auto* memoryExport = importedInstance->wasm.getExport(memory->base);
-      return importedInstance->getMemoryInstanceInfo(
-        *memoryExport->getInternalName());
+    auto* instance = self();
+    Export* memoryExport = nullptr;
+    for (auto* memory = instance->wasm.getMemory(name); memory->imported();
+         memory = instance->wasm.getMemory(*memoryExport->getInternalName())) {
+      instance = instance->linkedInstances.at(memory->module).get();
+      memoryExport = instance->wasm.getExport(memory->base);
+    }
+
+    if (memoryExport) {
+      return instance->getMemoryInstanceInfo(*memoryExport->getInternalName());
     }
 
     return MemoryInstanceInfo{self(), name};
@@ -3385,6 +3466,11 @@ class ModuleRunnerBase : public ExpressionRunner<SubType> {
   }
 
   Address getMemorySize(Name memory) {
+    auto info = getMemoryInstanceInfo(memory);
+    if (info.instance != self()) {
+      return info.instance->getMemorySize(info.name);
+    }
+
     auto iter = memorySizes.find(memory);
     if (iter == memorySizes.end()) {
       externalInterface->trap("getMemorySize called on non-existing memory");
@@ -3397,7 +3483,7 @@ class ModuleRunnerBase : public ExpressionRunner<SubType> {
     if (iter == memorySizes.end()) {
       externalInterface->trap("setMemorySize called on non-existing memory");
     }
-    memorySizes[memory] = size;
+    iter->second = size;
   }
 
 public:
@@ -4682,12 +4768,14 @@ class ModuleRunnerBase : public ExpressionRunner<SubType> {
   }
   Flow visitStackSwitch(StackSwitch* curr) { return Flow(NONCONSTANT_FLOW); }
 
-  void trap(const char* why) override {
+  void trap(std::string_view why) override {
     // Traps break all current continuations - they will never be resumable.
     self()->clearContinuationStore();
     externalInterface->trap(why);
   }
 
+  void trap(const char* why) override { trap(std::string_view(why)); }
+
   void hostLimit(const char* why) override {
     self()->clearContinuationStore();
     externalInterface->hostLimit(why);
diff --git a/src/wasm.h b/src/wasm.h
@@ -2435,6 +2435,28 @@ class Table : public Importable {
     initial = 0;
     max = kMaxSize;
   }
+
+  static bool isSubType(const Table& a, const Table& b) {
+    if (a.addressType != b.addressType) {
+      return false;
+    }
+
+    if (!Type::isSubType(a.type, b.type)) {
+      return false;
+    }
+
+    if (a.initial > b.initial) {
+      return false;
+    }
+
+    if (a.max < b.max) {
+      return false;
+    }
+
+    return true;
+  }
+
+  bool isSubType(const Table& other) { return Table::isSubType(*this, other); }
 };
 
 class DataSegment : public Named {
@@ -2470,6 +2492,15 @@ class Memory : public Importable {
     shared = false;
     addressType = Type::i32;
   }
+
+  static bool isSubType(const Memory& a, const Memory& b) {
+    return a.shared == b.shared && a.addressType == b.addressType &&
+           a.initial >= b.initial && a.max <= b.max;
+  }
+
+  bool isSubType(const Memory& other) {
+    return Memory::isSubType(*this, other);
+  }
 };
 
 class Global : public Importable {
diff --git a/test/spec/exact-func-import.wast b/test/spec/exact-func-import.wast
@@ -1,29 +1,27 @@
 ;; TODO: Use the upstream version from the custom descriptors proposal.
 
-(module
+(module definition
   (type $f (func))
   (import "" "" (func $1 (exact (type 0))))
-  (import "" "" (func $2 (exact (type $f) (param) (result))))
-  (import "" "" (func $3 (exact (type $f))))
-  (import "" "" (func $4 (exact (type 1)))) ;; Implicitly defined next
-  (import "" "" (func $5 (exact (param i32) (result i64))))
+  ;; (import "" "" (func $2 (exact (type $f) (param) (result)))) ;; TODO: parser support
+  (import "" "" (func $2 (exact (type $f))))
+  (import "" "" (func $3 (exact (type 1)))) ;; Implicitly defined next
+  (import "" "" (func $4 (exact (param i32) (result i64))))
 
-  (func $6 (import "" "") (exact (type 0)))
-  (func $7 (import "" "") (exact (type $f) (param) (result)))
-  (func $8 (import "" "") (exact (type $f)))
-  (func $9 (import "" "") (exact (type 2))) ;; Implicitly defined next
-  (func $10 (import "" "") (exact (param i64) (result i32)))
+  (func $5 (import "" "") (exact (type 0)))
+  ;; (func $6 (import "" "") (exact (type $f) (param) (result))) ;; TODO: parser support
+  (func $6 (import "" "") (exact (type $f)))
+  ;; (func $7 (import "" "") (exact (type 2))) ;; Implicitly defined next
+  ;; (func $8 (import "" "") (exact (param i64) (result i32))) ;; TODO: parser support
 
   (global (ref (exact $f)) (ref.func $1))
   (global (ref (exact $f)) (ref.func $2))
-  (global (ref (exact $f)) (ref.func $3))
+  (global (ref (exact 1)) (ref.func $3))
   (global (ref (exact 1)) (ref.func $4))
-  (global (ref (exact 1)) (ref.func $5))
+  (global (ref (exact $f)) (ref.func $5))
   (global (ref (exact $f)) (ref.func $6))
-  (global (ref (exact $f)) (ref.func $7))
-  (global (ref (exact $f)) (ref.func $8))
-  (global (ref (exact 2)) (ref.func $9))
-  (global (ref (exact 2)) (ref.func $10))
+  ;; (global (ref (exact 2)) (ref.func $7))
+  ;; (global (ref (exact 2)) (ref.func $8))
 )
 
 ;; References to inexact imports are not exact.
@@ -51,7 +49,7 @@
 
 ;; Inexact imports can still be referenced inexactly, though.
 
-(module
+(module definition
   (type $f (func))
   (import "" "" (func $1 (type $f)))
   (global (ref $f) (ref.func $1))
@@ -70,7 +68,9 @@
 ;; Import and re-export inexactly.
 (module $B
   (type $f (func))
-  (func (export "f") (import "A" "f") (type $f))
+  ;; (func (import "A" "f") (export "f") (type $f))
+  (func (import "A" "f") (type $f))
+  (export "f" (func 0))
 )
 (register "B")
 
@@ -220,7 +220,7 @@
 ;; Test the binary format
 
 ;; Exact function imports use 0x20.
-(module binary
+(module definition binary
   "\00asm" "\01\00\00\00"
   "\01"  ;; Type section id
   "\04"  ;; Type section length
@@ -265,4 +265,4 @@
     "\0b"  ;; End
   )
   "malformed export kind"
-)
+)
diff --git a/test/spec/ref_func.wast b/test/spec/ref_func.wast
@@ -1,6 +1,9 @@
+;; TODO: use test/spec/testsuite/ref_func.wast once it's fixed.
+
 (module
   (func (export "f") (param $x i32) (result i32) (local.get $x))
 )
+(register "M")
 (module
   (func $f (import "M" "f") (param i32) (result i32))
   (func $g (param $x i32) (result i32) (i32.add (local.get $x) (i32.const 1)))
diff --git a/test/spec/tags.wast b/test/spec/tags.wast
@@ -1,5 +1,11 @@
 ;; Test tags
 
+(module
+  (tag (export "im0") (param i32))
+  (tag (export "im1") (param i32 f32))
+)
+(register "env")
+
 (module
   (tag $e-import (import "env" "im0") (param i32))
   (import "env" "im1" (tag (param i32 f32)))

Original file line number	Diff line number	Diff line change
`@@ -176,6 +176,8 @@ struct Shell {`
`176`	`176`	`// SIMD instructions.`
`177`	`177`	`instance->setRelaxedBehavior(ModuleRunner::RelaxedBehavior::Execute);`
`178`	`178`	`instance->instantiate();`
	`179`	`+ } catch (const std::exception& e) {`
	`180`	`+ return Err{std::string("failed to instantiate module: ") + e.what()};`
`179`	`181`	`} catch (...) {`
`180`	`182`	`return Err{"failed to instantiate module"};`
`181`	`183`	`}`