RemoveExports pass

src/passes/CMakeLists.txt

@@ -105,6 +105,7 @@ set(passes_SOURCES
   TraceCalls.cpp
   RandomizeBranchHints.cpp
   RedundantSetElimination.cpp
+  RemoveExports.cpp
   RemoveImports.cpp
   RemoveMemoryInit.cpp
   RemoveNonJSOps.cpp

src/passes/RemoveExports.cpp

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2026 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.
+ */
+
+//
+// Remove exports using a wildcard. For example:
+//
+//  --remove-exports=__*
+//
+// That will remove all exports with names like "__foo" and "__bar".
+//
+
+#include "pass.h"
+#include "support/string.h"
+#include "wasm.h"
+
+namespace wasm {
+
+namespace {
+
+struct RemoveExports : public Pass {
+  void run(Module* module) override {
+    std::string pattern =
+      getArgument(name, "Usage usage:  wasm-opt --" + name + "=WILDCARD");
+
+    std::vector<Name> toRemove;
+    for (auto& exp : module->exports) {
+      if (String::wildcardMatch(pattern, exp->name.toString())) {
+        toRemove.push_back(exp->name);
+      }
+    }
+
+    for (auto& name : toRemove) {
+      module->removeExport(name);
+    }
+  }
+};
+
+} // anonymous namespace
+
+Pass* createRemoveExportsPass() { return new RemoveExports(); }
+
+} // namespace wasm

src/passes/pass.cpp

@@ -412,6 +412,9 @@ void PassRegistry::registerPasses() {
   registerPass("remove-relaxed-simd",
                "replaces relaxed SIMD instructions with unreachable",
                createRemoveRelaxedSIMDPass);
+  registerPass("remove-exports",
+               "removes exports using a wildcard",
+               createRemoveExportsPass);
   registerPass("remove-imports",
                "removes imports and replaces them with nops",
                createRemoveImportsPass);

src/passes/passes.h

@@ -135,6 +135,7 @@ Pass* createPropagateGlobalsGloballyPass();
 Pass* createRandomizeBranchHintsPass();
 Pass* createRemoveNonJSOpsPass();
 Pass* createRemoveRelaxedSIMDPass();
+Pass* createRemoveExportsPass();
 Pass* createRemoveImportsPass();
 Pass* createRemoveMemoryInitPass();
 Pass* createRemoveUnusedBrsPass();

test/lit/help/wasm-metadce.test

@@ -383,6 +383,8 @@
 ;; CHECK-NEXT:   --propagate-globals-globally                  propagate global values to other
 ;; CHECK-NEXT:                                                 globals (useful for tests)
 ;; CHECK-NEXT:
+;; CHECK-NEXT:   --remove-exports                              removes exports using a wildcard
+;; CHECK-NEXT:
 ;; CHECK-NEXT:   --remove-imports                              removes imports and replaces
 ;; CHECK-NEXT:                                                 them with nops
 ;; CHECK-NEXT:

test/lit/help/wasm-opt.test

@@ -415,6 +415,8 @@
 ;; CHECK-NEXT:   --propagate-globals-globally                  propagate global values to other
 ;; CHECK-NEXT:                                                 globals (useful for tests)
 ;; CHECK-NEXT:
+;; CHECK-NEXT:   --remove-exports                              removes exports using a wildcard
+;; CHECK-NEXT:
 ;; CHECK-NEXT:   --remove-imports                              removes imports and replaces
 ;; CHECK-NEXT:                                                 them with nops
 ;; CHECK-NEXT:

test/lit/help/wasm2js.test

@@ -347,6 +347,8 @@
 ;; CHECK-NEXT:   --propagate-globals-globally                  propagate global values to other
 ;; CHECK-NEXT:                                                 globals (useful for tests)
 ;; CHECK-NEXT:
+;; CHECK-NEXT:   --remove-exports                              removes exports using a wildcard
+;; CHECK-NEXT:
 ;; CHECK-NEXT:   --remove-imports                              removes imports and replaces
 ;; CHECK-NEXT:                                                 them with nops
 ;; CHECK-NEXT:

test/lit/passes/remove-exports.wast

@@ -0,0 +1,77 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.
+;; NOTE: This test was ported using port_passes_tests_to_lit.py and could be cleaned up.
+
+;; RUN: foreach %s %t wasm-opt "--remove-exports=__*" -all -S -o - | filecheck %s
+
+;; foo and bar will be kept as exports, but __foo, __bar, and __ will not.
+(module
+  ;; CHECK:      (type $0 (func))
+
+  ;; CHECK:      (export "foo" (func $foo))
+
+  ;; CHECK:      (export "bar" (func $bar))
+
+  ;; CHECK:      (func $foo (type $0)
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (i32.const 1)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $foo (export "foo")
+    (drop (i32.const 1))
+  )
+
+  ;; CHECK:      (func $__foo (type $0)
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (i32.const 2)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $__foo (export "__foo")
+    (drop (i32.const 2))
+  )
+
+  ;; CHECK:      (func $bar (type $0)
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (i32.const 3)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $bar (export "bar")
+    (drop (i32.const 3))
+  )
+
+  ;; CHECK:      (func $__bar (type $0)
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (i32.const 4)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $__bar (export "__bar")
+    (drop (i32.const 4))
+  )
+
+  ;; CHECK:      (func $__ (type $0)
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (i32.const 4)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $__ (export "__")
+    (drop (i32.const 4))
+  )
+)
+
+;; Test non-function exports. The prefixed __mem and __table exports vanish.
+(module
+  ;; CHECK:      (memory $memory 10 20)
+  (memory $memory 10 20)
+
+  ;; CHECK:      (table $table 10 20 funcref)
+  (table $table 10 20 funcref)
+
+  ;; CHECK:      (export "mem" (memory $memory))
+  (export "mem" (memory $memory))
+
+  (export "__mem" (memory $memory))
+
+  ;; CHECK:      (export "tab" (table $table))
+  (export "tab" (table $table))
+
+  (export "__tab" (table $table))
+)