[wasm] Initial implementation of catch-all decoding.

This adds basic support for decoding catch-all expressions as part of a
try block. Note that control flow and code generation support is still
missing.

R=clemensh@chromium.org
TEST=unittests/FunctionBodyDecoderTest.TryCatchAll
BUG=v8:8091

Change-Id: I10a1aa3e3e0418e0a04965e8318c94f449a00bb4
Reviewed-on: https://chromium-review.googlesource.com/c/1268059
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56444}

src/wasm/function-body-decoder-impl.h

@@ -487,7 +487,8 @@ enum ControlKind : uint8_t {
   kControlBlock,
   kControlLoop,
   kControlTry,
-  kControlTryCatch
+  kControlTryCatch,
+  kControlTryCatchAll
 };
 
 enum Reachability : uint8_t {
@@ -534,9 +535,12 @@ struct ControlBase {
   bool is_if_else() const { return kind == kControlIfElse; }
   bool is_block() const { return kind == kControlBlock; }
   bool is_loop() const { return kind == kControlLoop; }
-  bool is_try() const { return is_incomplete_try() || is_try_catch(); }
   bool is_incomplete_try() const { return kind == kControlTry; }
   bool is_try_catch() const { return kind == kControlTryCatch; }
+  bool is_try_catchall() const { return kind == kControlTryCatchAll; }
+  bool is_try() const {
+    return is_incomplete_try() || is_try_catch() || is_try_catchall();
+  }
 
   inline Merge<Value>* br_merge() {
     return is_loop() ? &this->start_merge : &this->end_merge;
@@ -1530,9 +1534,22 @@ class WasmFullDecoder : public WasmDecoder<validate> {
             break;
           }
           case kExprCatchAll: {
-            // TODO(kschimpf): Implement.
             CHECK_PROTOTYPE_OPCODE(eh);
-            OPCODE_ERROR(opcode, "not implemented yet");
+            if (!VALIDATE(!control_.empty())) {
+              this->error("catch-all does not match any try");
+              break;
+            }
+            Control* c = &control_.back();
+            if (!VALIDATE(c->is_try())) {
+              this->error("catch-all does not match any try");
+              break;
+            }
+            if (!VALIDATE(!c->is_try_catchall())) {
+              this->error("catch-all already present for try");
+              break;
+            }
+            c->kind = kControlTryCatchAll;
+            // TODO(mstarzinger): Implement control flow for catch-all.
             break;
           }
           case kExprLoop: {
@@ -1587,7 +1604,7 @@ class WasmFullDecoder : public WasmDecoder<validate> {
             }
             Control* c = &control_.back();
             if (!VALIDATE(!c->is_incomplete_try())) {
-              this->error(this->pc_, "missing catch in try");
+              this->error(this->pc_, "missing catch or catch-all in try");
               break;
             }
             if (c->is_onearmed_if()) {

test/unittests/wasm/function-body-decoder-unittest.cc

@@ -2433,24 +2433,30 @@ TEST_F(FunctionBodyDecoderTest, ThrowUnreachable) {
 
 TEST_F(FunctionBodyDecoderTest, TryCatch) {
   WASM_FEATURE_SCOPE(eh);
-
   TestModuleBuilder builder;
   module = builder.module();
-  builder.AddException(sigs.v_v());
-  builder.AddException(sigs.v_v());
-
-  // TODO(kschimpf): Need to fix catch to use declared exception.
-  EXPECT_VERIFIES(v_v, WASM_TRY_OP, WASM_CATCH(0), kExprEnd);
-
-  // Missing catch.
-  EXPECT_FAILURE(v_v, WASM_TRY_OP, kExprEnd);
+  byte ex1 = builder.AddException(sigs.v_v());
+  byte ex2 = builder.AddException(sigs.v_v());
+  EXPECT_VERIFIES(v_v, WASM_TRY_OP, WASM_CATCH(ex1), kExprEnd);
+  EXPECT_FAILURE(v_v, WASM_TRY_OP, kExprEnd);         // Missing catch.
+  EXPECT_FAILURE(v_v, WASM_TRY_OP, WASM_CATCH(ex1));  // Missing end.
+  EXPECT_FAILURE(v_v, WASM_CATCH(ex1), kExprEnd);     // Missing try.
 
-  // Missing end.
-  EXPECT_FAILURE(v_i, WASM_TRY_OP, WASM_CATCH(0));
+  // TODO(mstarzinger): Double catch. Fix this to verify.
+  EXPECT_FAILURE(v_v, WASM_TRY_OP, WASM_CATCH(ex1), WASM_CATCH(ex2), kExprEnd);
+}
 
-  // Double catch.
-  // TODO(kschimpf): Fix this to verify.
-  EXPECT_FAILURE(v_i, WASM_TRY_OP, WASM_CATCH(0), WASM_CATCH(1), kExprEnd);
+TEST_F(FunctionBodyDecoderTest, TryCatchAll) {
+  WASM_FEATURE_SCOPE(eh);
+  TestModuleBuilder builder;
+  module = builder.module();
+  byte ex1 = builder.AddException(sigs.v_v());
+  EXPECT_VERIFIES(v_v, WASM_TRY_OP, kExprCatchAll, kExprEnd);
+  EXPECT_VERIFIES(v_v, WASM_TRY_OP, WASM_CATCH(ex1), kExprCatchAll, kExprEnd);
+  EXPECT_FAILURE(v_v, WASM_TRY_OP, kExprCatchAll, kExprCatchAll, kExprEnd);
+  EXPECT_FAILURE(v_v, WASM_TRY_OP, kExprCatchAll, WASM_CATCH(ex1), kExprEnd);
+  EXPECT_FAILURE(v_v, WASM_TRY_OP, kExprCatchAll);  // Missing end.
+  EXPECT_FAILURE(v_v, kExprCatchAll, kExprEnd);     // Missing try.
 }
 
 #undef WASM_TRY_OP