[StackIR] Allow StackIR to be disabled from the commandline (#6725)

Normally we use it when optimizing (above a certain level). This lets the user
prevent it from being used even then.

Also add optimization options to wasm-metadce so that this is possible
there as well and not just in wasm-opt (this also opens the door to running
more passes in metadce, which may be useful later).

2 files changed, 18 insertions, 3 deletions

diff --git a/src/tools/optimization-options.h b/src/tools/optimization-options.h
index 8772edd29..af468769d 100644
--- a/src/tools/optimization-options.h
+++ b/src/tools/optimization-options.h
@@ -26,12 +26,17 @@
 namespace wasm {
 
 struct OptimizationOptions : public ToolOptions {
+  // By default we allow StackIR and enable it by default in higher optimization
+  // levels, but users can disallow it as well.
+  bool allowStackIR = true;
+
   void parse(int argc, const char* argv[]) {
     ToolOptions::parse(argc, argv);
 
     // After parsing the arguments, update defaults based on the optimize/shrink
     // levels.
-    if (passOptions.optimizeLevel >= 2 || passOptions.shrinkLevel >= 1) {
+    if (allowStackIR &&
+        (passOptions.optimizeLevel >= 2 || passOptions.shrinkLevel >= 1)) {
       passOptions.generateStackIR = true;
       passOptions.optimizeStackIR = true;
     }
@@ -191,6 +196,16 @@ struct OptimizationOptions : public ToolOptions {
            [&](Options* o, const std::string& arguments) {
              passOptions.debugInfo = true;
            })
+      .add("--no-stack-ir",
+           "",
+           "do not use StackIR (even when it is the default)",
+           ToolOptionsCategory,
+           Options::Arguments::Zero,
+           [&](Options* o, const std::string& arguments) {
+             allowStackIR = false;
+             passOptions.generateStackIR = false;
+             passOptions.optimizeStackIR = false;
+           })
       .add("--always-inline-max-function-size",
            "-aimfs",
            "Max size of functions that are always inlined (default " +
diff --git a/src/tools/wasm-metadce.cpp b/src/tools/wasm-metadce.cpp
index 301470206..9cc06375e 100644
--- a/src/tools/wasm-metadce.cpp
+++ b/src/tools/wasm-metadce.cpp
@@ -29,11 +29,11 @@
 #include "asmjs/shared-constants.h"
 #include "ir/element-utils.h"
 #include "ir/module-utils.h"
+#include "optimization-options.h"
 #include "pass.h"
 #include "support/colors.h"
 #include "support/file.h"
 #include "support/json.h"
-#include "tool-options.h"
 #include "wasm-builder.h"
 #include "wasm-io.h"
 #include "wasm-validator.h"
@@ -371,7 +371,7 @@ int main(int argc, const char* argv[]) {
 
   const std::string WasmMetaDCEOption = "wasm-opt options";
 
-  ToolOptions options(
+  OptimizationOptions options(
     "wasm-metadce",
     "This tool performs dead code elimination (DCE) on a larger space "
     "that the wasm module is just a part of. For example, if you have "