[wasm] Base {CallIndirectImmediate} on {TableIndexImmediate}.

This makes sure that all encodings of a table index are based upon a
single implementation in the {TableIndexImmediate} class. It also fixes
one encoding that wasn't extended to support u32v yet.

R=ahaas@chromium.org
TEST=unittests/WasmOpcodeLengthTest.VariableLength

Change-Id: If24b6dc5e303d2d9e1e91cb2640c7c13eac40198
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1768375Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63408}

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

@@ -338,35 +338,6 @@ struct BranchOnExceptionImmediate {
   }
 };
 
-template <Decoder::ValidateFlag validate>
-struct CallIndirectImmediate {
-  uint32_t table_index;
-  uint32_t sig_index;
-  FunctionSig* sig = nullptr;
-  uint32_t length = 0;
-  inline CallIndirectImmediate(const WasmFeatures enabled, Decoder* decoder,
-                               const byte* pc) {
-    uint32_t len = 0;
-    sig_index = decoder->read_u32v<validate>(pc + 1, &len, "signature index");
-    table_index = decoder->read_u8<validate>(pc + 1 + len, "table index");
-    if (!VALIDATE(table_index == 0 || enabled.anyref)) {
-      decoder->errorf(pc + 1 + len, "expected table index 0, found %u",
-                      table_index);
-    }
-    length = 1 + len;
-  }
-};
-
-template <Decoder::ValidateFlag validate>
-struct CallFunctionImmediate {
-  uint32_t index;
-  FunctionSig* sig = nullptr;
-  uint32_t length;
-  inline CallFunctionImmediate(Decoder* decoder, const byte* pc) {
-    index = decoder->read_u32v<validate>(pc + 1, &length, "function index");
-  }
-};
-
 template <Decoder::ValidateFlag validate>
 struct FunctionIndexImmediate {
   uint32_t index = 0;
@@ -399,6 +370,36 @@ struct TableIndexImmediate {
   }
 };
 
+template <Decoder::ValidateFlag validate>
+struct CallIndirectImmediate {
+  uint32_t table_index;
+  uint32_t sig_index;
+  FunctionSig* sig = nullptr;
+  uint32_t length = 0;
+  inline CallIndirectImmediate(const WasmFeatures enabled, Decoder* decoder,
+                               const byte* pc) {
+    uint32_t len = 0;
+    sig_index = decoder->read_u32v<validate>(pc + 1, &len, "signature index");
+    TableIndexImmediate<validate> table(decoder, pc + len);
+    if (!VALIDATE((table.index == 0 && table.length == 1) || enabled.anyref)) {
+      decoder->errorf(pc + 1 + len, "expected table index 0, found %u",
+                      table.index);
+    }
+    table_index = table.index;
+    length = len + table.length;
+  }
+};
+
+template <Decoder::ValidateFlag validate>
+struct CallFunctionImmediate {
+  uint32_t index;
+  FunctionSig* sig = nullptr;
+  uint32_t length;
+  inline CallFunctionImmediate(Decoder* decoder, const byte* pc) {
+    index = decoder->read_u32v<validate>(pc + 1, &length, "function index");
+  }
+};
+
 template <Decoder::ValidateFlag validate>
 struct BranchTableImmediate {
   uint32_t table_count;

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

@@ -3525,6 +3525,24 @@ TEST_F(WasmOpcodeLengthTest, VariableLength) {
   ExpectLength(4, kExprRefFunc, U32V_3(44));
   ExpectLength(5, kExprRefFunc, U32V_4(66));
   ExpectLength(6, kExprRefFunc, U32V_5(77));
+
+  ExpectLength(2, kExprTableGet, U32V_1(1));
+  ExpectLength(3, kExprTableGet, U32V_2(33));
+  ExpectLength(4, kExprTableGet, U32V_3(44));
+  ExpectLength(5, kExprTableGet, U32V_4(66));
+  ExpectLength(6, kExprTableGet, U32V_5(77));
+
+  ExpectLength(2, kExprTableSet, U32V_1(1));
+  ExpectLength(3, kExprTableSet, U32V_2(33));
+  ExpectLength(4, kExprTableSet, U32V_3(44));
+  ExpectLength(5, kExprTableSet, U32V_4(66));
+  ExpectLength(6, kExprTableSet, U32V_5(77));
+
+  ExpectLength(3, kExprCallIndirect, U32V_1(1), U32V_1(1));
+  ExpectLength(4, kExprCallIndirect, U32V_1(1), U32V_2(33));
+  ExpectLength(5, kExprCallIndirect, U32V_1(1), U32V_3(44));
+  ExpectLength(6, kExprCallIndirect, U32V_1(1), U32V_4(66));
+  ExpectLength(7, kExprCallIndirect, U32V_1(1), U32V_5(77));
 }
 
 TEST_F(WasmOpcodeLengthTest, LoadsAndStores) {