6 files changed, 68 insertions, 1 deletions
diff --git a/src/tools/wasm-merge.cpp b/src/tools/wasm-merge.cpp
index ff2ab6d46..47dd1e111 100644
--- a/src/tools/wasm-merge.cpp
+++ b/src/tools/wasm-merge.cpp
@@ -235,6 +235,21 @@ void updateNames(Module& wasm, KindNameUpdates& kindNameUpdates) {
     }
 
   private:
+    Name resolveName(NameUpdates& updates, const Name newName) {
+      // Iteratively lookup the updated name
+      // We detect loops to ensure termination
+      std::set<Name> visited;
+      Name name = newName;
+      while (1) {
+        auto iter = updates.find(name);
+        if (iter == updates.end() || visited.find(name) != visited.end()) {
+          return name;
+        }
+        visited.insert(name);
+        name = iter->second;
+      }
+    }
+
     void mapName(ModuleItemKind kind, Name& name) {
       auto iter = kindNameUpdates.find(kind);
       if (iter == kindNameUpdates.end()) {
@@ -243,7 +258,7 @@ void updateNames(Module& wasm, KindNameUpdates& kindNameUpdates) {
       auto& nameUpdates = iter->second;
       auto iter2 = nameUpdates.find(name);
       if (iter2 != nameUpdates.end()) {
-        name = iter2->second;
+        name = resolveName(nameUpdates, iter2->second);
       }
     }
   } nameMapper(kindNameUpdates);
diff --git a/test/lit/merge/chain.wat b/test/lit/merge/chain.wat
new file mode 100644
index 000000000..f87914931
--- /dev/null
+++ b/test/lit/merge/chain.wat
@@ -0,0 +1,24 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.
+;; RUN: wasm-merge %s first %s.second second %s.third third --rename-export-conflicts -all -S -o - | filecheck %s
+
+;; Test chains of imports / exports: the first module export a function,
+;; which is reexported by the second and imported by the third.
+
+(module
+  (func (export "f"))
+)
+;; CHECK:      (type $none_=>_none (func))
+
+;; CHECK:      (export "f" (func $0))
+
+;; CHECK:      (export "g" (func $0))
+
+;; CHECK:      (export "h" (func $0_2))
+
+;; CHECK:      (func $0 (type $none_=>_none)
+;; CHECK-NEXT:  (nop)
+;; CHECK-NEXT: )
+
+;; CHECK:      (func $0_2 (type $none_=>_none)
+;; CHECK-NEXT:  (call $0)
+;; CHECK-NEXT: )
diff --git a/test/lit/merge/chain.wat.second b/test/lit/merge/chain.wat.second
new file mode 100644
index 000000000..dae1ace36
--- /dev/null
+++ b/test/lit/merge/chain.wat.second
@@ -0,0 +1,4 @@
+(module
+  (import "first" "f" (func $f))
+  (export "g" (func $f))
+)
diff --git a/test/lit/merge/chain.wat.third b/test/lit/merge/chain.wat.third
new file mode 100644
index 000000000..cffbe5ba6
--- /dev/null
+++ b/test/lit/merge/chain.wat.third
@@ -0,0 +1,4 @@
+(module
+  (import "second" "g" (func $g))
+  (func (export "h") (call $g))
+)
diff --git a/test/lit/merge/import_cycle.wat b/test/lit/merge/import_cycle.wat
new file mode 100644
index 000000000..0261eabc5
--- /dev/null
+++ b/test/lit/merge/import_cycle.wat
@@ -0,0 +1,16 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.
+;; RUN: wasm-merge %s first %s.second second -S -o - | filecheck %s
+
+;; Test that wasm-merge terminates when there are importation cycles
+
+(module
+  ;; CHECK:      (type $none_=>_none (func))
+
+  ;; CHECK:      (import "second" "g" (func $f))
+  (import "second" "g" (func $f))
+  ;; CHECK:      (import "first" "f" (func $f_1))
+
+  ;; CHECK:      (export "f" (func $f_1))
+  (export "f" (func $f))
+)
+;; CHECK:      (export "g" (func $f))
diff --git a/test/lit/merge/import_cycle.wat.second b/test/lit/merge/import_cycle.wat.second
new file mode 100644
index 000000000..dae1ace36
--- /dev/null
+++ b/test/lit/merge/import_cycle.wat.second
@@ -0,0 +1,4 @@
+(module
+  (import "first" "f" (func $f))
+  (export "g" (func $f))
+)