Use effects for indirect call expressions

Author: stevenfontanella

src/ir/effects.h

@@ -770,6 +770,12 @@ class EffectAnalyzer {
       }
     }
     void visitCallIndirect(CallIndirect* curr) {
+      if (auto it = parent.module.typeEffects.find(curr->heapType);
+          it != parent.module.typeEffects.end()) {
+        parent.mergeIn(*it->second);
+        return;
+      }
+
       parent.calls = true;
       if (curr->isReturn) {
         parent.branchesOut = true;
@@ -1040,6 +1046,14 @@ class EffectAnalyzer {
       if (trapOnNull(curr->target)) {
         return;
       }
+
+      if (auto it =
+            parent.module.typeEffects.find(curr->target->type.getHeapType());
+          it != parent.module.typeEffects.end()) {
+        parent.mergeIn(*it->second);
+        return;
+      }
+
       if (curr->isReturn) {
         parent.branchesOut = true;
         if (parent.features.hasExceptionHandling()) {

src/passes/GlobalEffects.cpp

@@ -26,6 +26,7 @@
 #include "pass.h"
 #include "support/graph_traversal.h"
 #include "support/strongly_connected_components.h"
+#include "support/utilities.h"
 #include "wasm.h"
 
 namespace wasm {
@@ -227,10 +228,13 @@ void mergeMaybeEffects(std::optional<EffectAnalyzer>& dest,
 // - Merge all of the effects of functions within the CC
 // - Also merge the (already computed) effects of each callee CC
 // - Add trap effects for potentially recursive call chains
-void propagateEffects(const Module& module,
-                      const PassOptions& passOptions,
-                      std::map<Function*, FuncInfo>& funcInfos,
-                      const CallGraph& callGraph) {
+void propagateEffects(
+  const Module& module,
+  const PassOptions& passOptions,
+  std::map<Function*, FuncInfo>& funcInfos,
+  std::unordered_map<HeapType, std::shared_ptr<const EffectAnalyzer>>&
+    typeEffects,
+  const CallGraph& callGraph) {
   // We only care about Functions that are roots, not types.
   // A type would be a root if a function exists with that type, but no-one
   // indirect calls the type.
@@ -319,12 +323,21 @@ void propagateEffects(const Module& module,
     }
 
     // Assign each function's effects to its CC effects.
-    for (Function* f : ccFuncs) {
-      if (!ccEffects) {
-        funcInfos.at(f).effects = UnknownEffects;
-      } else {
-        funcInfos.at(f).effects.emplace(*ccEffects);
-      }
+    for (auto node : cc) {
+      std::visit(overloaded{[&](HeapType type) {
+                              if (ccEffects != UnknownEffects) {
+                                typeEffects[type] =
+                                  std::make_shared<EffectAnalyzer>(*ccEffects);
+                              }
+                            },
+                            [&](Function* f) {
+                              if (!ccEffects) {
+                                funcInfos.at(f).effects = UnknownEffects;
+                              } else {
+                                funcInfos.at(f).effects.emplace(*ccEffects);
+                              }
+                            }},
+                 node);
     }
   }
 }
@@ -348,7 +361,8 @@ struct GenerateGlobalEffects : public Pass {
     auto callGraph =
       buildCallGraph(*module, funcInfos, getPassOptions().closedWorld);
 
-    propagateEffects(*module, getPassOptions(), funcInfos, callGraph);
+    propagateEffects(
+      *module, getPassOptions(), funcInfos, module->typeEffects, callGraph);
 
     copyEffectsToFunctions(funcInfos);
   }

src/support/utilities.h

@@ -94,6 +94,10 @@ class Fatal {
 #define WASM_UNREACHABLE(msg) wasm::handle_unreachable()
 #endif
 
+template<class... Ts> struct overloaded : Ts... {
+  using Ts::operator()...;
+};
+
 } // namespace wasm
 
 #endif // wasm_support_utilities_h

src/wasm.h

@@ -2684,6 +2684,11 @@ class Module {
   std::unordered_map<HeapType, TypeNames> typeNames;
   std::unordered_map<HeapType, Index> typeIndices;
 
+  // Potential effects for bodies of indirect calls to this type.
+  // TODO: make this into Type
+  std::unordered_map<HeapType, std::shared_ptr<const EffectAnalyzer>>
+    typeEffects;
+
   MixedArena allocator;
 
 private:

test/lit/passes/global-effects-closed-world-tnh.wast

@@ -16,22 +16,9 @@
   )
 
   ;; CHECK:      (func $calls-nop-via-nullable-ref (type $1) (param $ref (ref null $nopType))
-  ;; CHECK-NEXT:  (call_ref $nopType
-  ;; CHECK-NEXT:   (i32.const 1)
-  ;; CHECK-NEXT:   (local.get $ref)
-  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT:  (nop)
   ;; CHECK-NEXT: )
   (func $calls-nop-via-nullable-ref (param $ref (ref null $nopType))
     (call_ref $nopType (i32.const 1) (local.get $ref))
   )
-
-  ;; CHECK:      (func $f (type $1) (param $ref (ref null $nopType))
-  ;; CHECK-NEXT:  (nop)
-  ;; CHECK-NEXT: )
-  (func $f (param $ref (ref null $nopType))
-    ;; The only possible implementation of $nopType has no effects.
-    ;; $calls-nop-via-nullable-ref may trap from a null reference, but
-    ;; --traps-never-happen is enabled, so we're free to optimize this out.
-    (call $calls-nop-via-nullable-ref (local.get $ref))
-  )
 )