Skip imports in table during RemoveImports (#2181)

This prevents RemoveImports from producing an invalid module that
references functions that no longer exist.

Author: tlively

src/passes/RemoveImports.cpp

@@ -48,8 +48,19 @@ struct RemoveImports : public WalkerPass<PostWalker<RemoveImports>> {
     std::vector<Name> names;
     ModuleUtils::iterImportedFunctions(
       *curr, [&](Function* func) { names.push_back(func->name); });
+    // Do not remove names referenced in a table
+    std::set<Name> indirectNames;
+    if (curr->table.exists) {
+      for (auto& segment : curr->table.segments) {
+        for (auto& name : segment.data) {
+          indirectNames.insert(name);
+        }
+      }
+    }
     for (auto& name : names) {
-      curr->removeFunction(name);
+      if (indirectNames.find(name) == indirectNames.end()) {
+        curr->removeFunction(name);
+      }
     }
   }
 };

test/passes/remove-imports.txt

@@ -2,15 +2,21 @@
  (type $FUNCSIG$v (func))
  (type $FUNCSIG$i (func (result i32)))
  (type $FUNCSIG$d (func (result f64)))
+ (import "env" "table" (table $0 1 1 funcref))
+ (elem (i32.const 0) $waka-sneaky)
  (import "env" "memBase" (global $import$global0 i32))
+ (import "somewhere" "waka-sneaky" (func $waka-sneaky))
  (memory $0 1024 1024)
- (func $nada (; 0 ;) (type $FUNCSIG$v)
+ (func $nada (; 1 ;) (type $FUNCSIG$v)
   (nop)
   (drop
    (i32.const 0)
   )
   (drop
    (f64.const 0)
   )
+  (call_indirect (type $FUNCSIG$v)
+   (i32.const 0)
+  )
  )
 )

test/passes/remove-imports.wast

@@ -6,7 +6,10 @@
   (import $waka "somewhere" "waka")
   (import $waka-ret "somewhere" "waka-ret" (result i32))
   (import $waka-ret-d "somewhere" "waka-ret-d" (result f64))
+  (import $waka-sneaky "somewhere" "waka-sneaky")
   (import "env" "memBase" (global i32))
+  (import "env" "table" (table $table 1 1 funcref))
+  (elem (i32.const 0) $waka-sneaky)
   (func $nada (type $FUNCSIG$v)
     (call $waka)
     (drop
@@ -15,5 +18,6 @@
     (drop
       (call $waka-ret-d)
     )
+    (call_indirect (i32.const 0))
   )
 )