Implement elem.drop (#7658)

Fixes #7209.

Author: osa1

scripts/gen-s-parser.py

@@ -582,6 +582,7 @@
     ("table.fill",           "makeTableFill()"),
     ("table.copy",           "makeTableCopy()"),
     ("table.init",           "makeTableInit()"),
+    ("elem.drop",            "makeElemDrop()"),
     # exception handling instructions
     ("try",                  "makeTry()"),
     ("try_table",            "makeTryTable()"),

scripts/test/shared.py

@@ -416,7 +416,6 @@ def get_tests(test_dir, extensions=[], recursive=False):
     'address.wast',  # 64-bit offset allowed by memory64
     'align.wast',    # Alignment bit 6 used by multi-memory
     'binary.wast',   # memory.grow reserved byte a LEB in multi-memory
-    'bulk.wast',     # Requires support for elem.drop
     'comments.wast',  # Issue with carriage returns being treated as newlines
     'const.wast',    # Hex float constant not recognized as out of range
     'conversions.wast',  # Promoted NaN should be canonical
@@ -450,7 +449,6 @@ def get_tests(test_dir, extensions=[], recursive=False):
     'type-equivalence.wast',  # Recursive types allowed by GC
     'unreached-invalid.wast',  # Requires more precise unreachable validation
     'array.wast',  # Requires support for table default elements
-    'array_init_elem.wast',  # Requires support for elem.drop
     'br_if.wast',  # Requires more precise branch validation
     'br_on_cast.wast',  # Requires host references to not be externalized i31refs
     'br_on_cast_fail.wast',  # Requires host references to not be externalized i31refs

src/gen-s-parser.inc

@@ -401,25 +401,36 @@ switch (buf[0]) {
     }
   }
   case 'e': {
-    switch (buf[7]) {
-      case 'c':
-        if (op == "extern.convert_any"sv) {
-          CHECK_ERR(makeRefAs(ctx, pos, annotations, ExternConvertAny));
-          return Ok{};
-        }
-        goto parse_error;
-      case 'e':
-        if (op == "extern.externalize"sv) {
-          CHECK_ERR(makeRefAs(ctx, pos, annotations, ExternConvertAny));
+    switch (buf[1]) {
+      case 'l':
+        if (op == "elem.drop"sv) {
+          CHECK_ERR(makeElemDrop(ctx, pos, annotations));
           return Ok{};
         }
         goto parse_error;
-      case 'i':
-        if (op == "extern.internalize"sv) {
-          CHECK_ERR(makeRefAs(ctx, pos, annotations, AnyConvertExtern));
-          return Ok{};
+      case 'x': {
+        switch (buf[7]) {
+          case 'c':
+            if (op == "extern.convert_any"sv) {
+              CHECK_ERR(makeRefAs(ctx, pos, annotations, ExternConvertAny));
+              return Ok{};
+            }
+            goto parse_error;
+          case 'e':
+            if (op == "extern.externalize"sv) {
+              CHECK_ERR(makeRefAs(ctx, pos, annotations, ExternConvertAny));
+              return Ok{};
+            }
+            goto parse_error;
+          case 'i':
+            if (op == "extern.internalize"sv) {
+              CHECK_ERR(makeRefAs(ctx, pos, annotations, AnyConvertExtern));
+              return Ok{};
+            }
+            goto parse_error;
+          default: goto parse_error;
         }
-        goto parse_error;
+      }
       default: goto parse_error;
     }
   }

src/interpreter/interpreter.cpp

@@ -233,6 +233,7 @@ struct ExpressionInterpreter : OverriddenVisitor<ExpressionInterpreter, Flow> {
   Flow visitTableFill(TableFill* curr) { WASM_UNREACHABLE("TODO"); }
   Flow visitTableCopy(TableCopy* curr) { WASM_UNREACHABLE("TODO"); }
   Flow visitTableInit(TableInit* curr) { WASM_UNREACHABLE("TODO"); }
+  Flow visitElemDrop(ElemDrop* curr) { WASM_UNREACHABLE("TODO"); }
   Flow visitTry(Try* curr) { WASM_UNREACHABLE("TODO"); }
   Flow visitTryTable(TryTable* curr) { WASM_UNREACHABLE("TODO"); }
   Flow visitThrow(Throw* curr) { WASM_UNREACHABLE("TODO"); }

src/ir/ReFinalize.cpp

@@ -127,6 +127,7 @@ void ReFinalize::visitTableGrow(TableGrow* curr) { curr->finalize(); }
 void ReFinalize::visitTableFill(TableFill* curr) { curr->finalize(); }
 void ReFinalize::visitTableCopy(TableCopy* curr) { curr->finalize(); }
 void ReFinalize::visitTableInit(TableInit* curr) { curr->finalize(); }
+void ReFinalize::visitElemDrop(ElemDrop* curr) { curr->finalize(); }
 void ReFinalize::visitTry(Try* curr) { curr->finalize(); }
 void ReFinalize::visitTryTable(TryTable* curr) {
   curr->finalize();

src/ir/child-typer.h

@@ -804,6 +804,8 @@ template<typename Subtype> struct ChildTyper : OverriddenVisitor<Subtype> {
     note(&curr->size, Type::i32);
   }
 
+  void visitElemDrop(ElemDrop* curr) {}
+
   void visitTry(Try* curr) {
     note(&curr->body, curr->type);
     for (auto& expr : curr->catchBodies) {

src/ir/cost.h

@@ -631,6 +631,7 @@ struct CostAnalyzer : public OverriddenVisitor<CostAnalyzer, CostType> {
   CostType visitTableInit(TableInit* curr) {
     return 6 + visit(curr->dest) + visit(curr->offset) + visit(curr->size);
   }
+  CostType visitElemDrop(ElemDrop* curr) { return 6; }
   CostType visitTry(Try* curr) {
     // We assume no exception will be thrown in most cases
     return visit(curr->body);

src/ir/effects.h

@@ -782,6 +782,7 @@ class EffectAnalyzer {
       parent.writesTable = true;
       parent.implicitTrap = true;
     }
+    void visitElemDrop(ElemDrop* curr) { parent.writesTable = true; }
     void visitTry(Try* curr) {
       if (curr->delegateTarget.is()) {
         parent.delegateTargets.insert(curr->delegateTarget);

src/ir/possible-contents.cpp

@@ -675,6 +675,7 @@ struct InfoCollector
   void visitTableFill(TableFill* curr) { addRoot(curr); }
   void visitTableCopy(TableCopy* curr) { addRoot(curr); }
   void visitTableInit(TableInit* curr) {}
+  void visitElemDrop(ElemDrop* curr) {}
 
   void visitNop(Nop* curr) {}
   void visitUnreachable(Unreachable* curr) {}

src/ir/subtype-exprs.h

@@ -243,6 +243,7 @@ struct SubtypingDiscoverer : public OverriddenVisitor<SubType> {
     self()->noteSubtype(seg->type,
                         self()->getModule()->getTable(curr->table)->type);
   }
+  void visitElemDrop(ElemDrop* curr) {}
   void visitTry(Try* curr) {
     self()->noteSubtype(curr->body, curr);
     for (auto* body : curr->catchBodies) {