Support --symbolmap and --symbolmap=FOO in wasm-opt (#3885)

wasm-as supports --symbolmap=FOO as an argument. We got a request to
support the same in wasm-opt. wasm-opt does have --print-function-map which
does the same, but as a pass. To unify them, use the new pass arg sugar from
#3882 which allows us to add a --symbolmap pass whose argument can be
set as --symbolmap=FOO. That perfectly matches the wasm-as notation.

For now, keep the old --print-function-map notation as well, to not break
emscripten. After we remove it there we can remove it here.

1 files changed, 7 insertions, 1 deletions

diff --git a/src/passes/PrintFunctionMap.cpp b/src/passes/PrintFunctionMap.cpp
index 75db495fa..c2be0f3a2 100644
--- a/src/passes/PrintFunctionMap.cpp
+++ b/src/passes/PrintFunctionMap.cpp
@@ -25,6 +25,7 @@
 //
 
 #include "pass.h"
+#include "support/file.h"
 #include "wasm.h"
 
 namespace wasm {
@@ -33,9 +34,14 @@ struct PrintFunctionMap : public Pass {
   bool modifiesBinaryenIR() override { return false; }
 
   void run(PassRunner* runner, Module* module) override {
+    // If an argument is provided, write to that file; otherwise write to
+    // stdout.
+    auto outFile = runner->options.getArgumentOrDefault("symbolmap", "");
+    Output output(outFile, Flags::Text);
+    auto& o = output.getStream();
     Index i = 0;
     for (auto& func : module->functions) {
-      std::cout << i++ << ':' << func->name.str << '\n';
+      o << i++ << ':' << func->name.str << '\n';
     }
   }
 };