[wasm] Use inline field inits

R=clemensh@chromium.org

Change-Id: Ib1a0105e3347a5ccafdb72dadd9aa144ab77732c
Reviewed-on: https://chromium-review.googlesource.com/1046970Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53035}

src/wasm/baseline/liftoff-assembler.h

@@ -677,10 +677,10 @@ class LiftoffStackSlots {
          RegPairHalf half)
         : src_(src), src_index_(src_index), half_(half) {}
     explicit Slot(const LiftoffAssembler::VarState& src)
-        : src_(src), src_index_(0), half_(kLowWord) {}
+        : src_(src), half_(kLowWord) {}
 
     const LiftoffAssembler::VarState src_;
-    uint32_t src_index_;
+    uint32_t src_index_ = 0;
     RegPairHalf half_;
   };
 

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

@@ -370,14 +370,13 @@ class BranchTableIterator {
       : decoder_(decoder),
         start_(imm.start),
         pc_(imm.table),
-        index_(0),
         table_count_(imm.table_count) {}
 
  private:
   Decoder* decoder_;
   const byte* start_;
   const byte* pc_;
-  uint32_t index_;        // the current index.
+  uint32_t index_ = 0;    // the current index.
   uint32_t table_count_;  // the count of entries, not including default.
 };
 

src/wasm/function-body-decoder.cc

@@ -71,9 +71,9 @@ class WasmGraphBuildingInterface {
 
   struct TryInfo : public ZoneObject {
     SsaEnv* catch_env;
-    TFNode* exception;
+    TFNode* exception = nullptr;
 
-    explicit TryInfo(SsaEnv* c) : catch_env(c), exception(nullptr) {}
+    explicit TryInfo(SsaEnv* c) : catch_env(c) {}
   };
 
   struct Control : public ControlWithNamedConstructors<Control, Value> {

src/wasm/function-body-decoder.h

@@ -77,11 +77,11 @@ inline DecodeResult BuildTFGraph(AccountingAllocator* allocator,
 
 struct BodyLocalDecls {
   // The size of the encoded declarations.
-  uint32_t encoded_size;  // size of encoded declarations
+  uint32_t encoded_size = 0;  // size of encoded declarations
 
   ZoneVector<ValueType> type_list;
 
-  explicit BodyLocalDecls(Zone* zone) : encoded_size(0), type_list(zone) {}
+  explicit BodyLocalDecls(Zone* zone) : type_list(zone) {}
 };
 
 V8_EXPORT_PRIVATE bool DecodeLocalDecls(BodyLocalDecls* decls,

src/wasm/wasm-interpreter.cc

@@ -656,18 +656,17 @@ struct InterpreterCode {
 class SideTable : public ZoneObject {
  public:
   ControlTransferMap map_;
-  uint32_t max_stack_height_;
+  uint32_t max_stack_height_ = 0;
 
   SideTable(Zone* zone, const WasmModule* module, InterpreterCode* code)
-      : map_(zone), max_stack_height_(0) {
+      : map_(zone) {
     // Create a zone for all temporary objects.
     Zone control_transfer_zone(zone->allocator(), ZONE_NAME);
 
     // Represents a control flow label.
     class CLabel : public ZoneObject {
       explicit CLabel(Zone* zone, uint32_t target_stack_height, uint32_t arity)
-          : target(nullptr),
-            target_stack_height(target_stack_height),
+          : target_stack_height(target_stack_height),
             arity(arity),
             refs(zone) {}
 
@@ -676,7 +675,7 @@ class SideTable : public ZoneObject {
         const byte* from_pc;
         const uint32_t stack_height;
       };
-      const byte* target;
+      const byte* target = nullptr;
       uint32_t target_stack_height;
       // Arity when branching to this label.
       const uint32_t arity;