Emit imported functions first in symbol maps (#3900)

Imported functions come first when modules are emitted, so to ensure the
function indices are correct, they need to come first in the symbol maps. We
never noticed this bug before because imported functions are always the first
functions when a module is parsed, so the bug never mattered in practice.
However, wasm-split adds new imported functions after parsing and these were
causing the symbol map indices to be incorrect.

2 files changed, 10 insertions, 3 deletions

diff --git a/src/passes/PrintFunctionMap.cpp b/src/passes/PrintFunctionMap.cpp
index c2be0f3a2..325f4e48d 100644
--- a/src/passes/PrintFunctionMap.cpp
+++ b/src/passes/PrintFunctionMap.cpp
@@ -24,6 +24,7 @@
 // 2:baz
 //
 
+#include "ir/module-utils.h"
 #include "pass.h"
 #include "support/file.h"
 #include "wasm.h"
@@ -40,9 +41,11 @@ struct PrintFunctionMap : public Pass {
     Output output(outFile, Flags::Text);
     auto& o = output.getStream();
     Index i = 0;
-    for (auto& func : module->functions) {
+    auto write = [&](Function* func) {
       o << i++ << ':' << func->name.str << '\n';
-    }
+    };
+    ModuleUtils::iterImportedFunctions(*module, write);
+    ModuleUtils::iterDefinedFunctions(*module, write);
   }
 };
 
diff --git a/test/lit/wasm-split/symbolmap.wast b/test/lit/wasm-split/symbolmap.wast
index 4fe0f5291..b1be9531b 100644
--- a/test/lit/wasm-split/symbolmap.wast
+++ b/test/lit/wasm-split/symbolmap.wast
@@ -3,7 +3,9 @@
 ;; RUN: filecheck %s --check-prefix SECONDARY-MAP < %t.2.wasm.symbols
 ;; RUN: wasm-dis %t.1.wasm | filecheck %s --check-prefix PRIMARY
 
-;; PRIMARY-MAP: 0:bar
+;; PRIMARY-MAP: 0:placeholder_0
+;; PRIMARY-MAP: 1:placeholder_2
+;; PRIMARY-MAP: 2:bar
 
 ;; SECONDARY-MAP: 0:baz
 ;; SECONDARY-MAP: 1:foo
@@ -12,6 +14,8 @@
 ;; PRIMARY: (func $0
 
 (module
+  (table $table 3 3 funcref)
+  (elem $table (i32.const 0) $foo $bar $baz)
   (func $foo
     (nop)
   )