Store protected instructions as unique_ptr

When generating code, store the vector of protected instruction data
as unique_ptr. It only becomes a shared_ptr once ownership has been
transferred to the NativeModule, because it can be shared between
different instances of the same function.

Drive-by: Remove dead accessor in PipelineData.

R=ahaas@chromium.org

Change-Id: I7571b32bf89f3c816683c5a77ac08fe8c22eb968
Reviewed-on: https://chromium-review.googlesource.com/853496Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50404}

src/compiler/pipeline.cc

@@ -253,11 +253,6 @@ class PipelineData {
     source_position_output_ = source_position_output;
   }
 
-  std::vector<trap_handler::ProtectedInstructionData>* protected_instructions()
-      const {
-    return protected_instructions_;
-  }
-
   JumpOptimizationInfo* jump_optimization_info() const {
     return jump_optimization_info_;
   }

src/compiler/wasm-compiler.cc

@@ -5139,7 +5139,7 @@ WasmCodeWrapper WasmCompilationUnit::FinishTurbofanCompilation(
         desc, tf_.job_->compilation_info()->wasm_code_desc()->frame_slot_count,
         func_index_,
         tf_.job_->compilation_info()->wasm_code_desc()->safepoint_table_offset,
-        protected_instructions_);
+        std::move(protected_instructions_));
     if (!code) {
       return WasmCodeWrapper(code);
     }
@@ -5243,9 +5243,10 @@ WasmCodeWrapper WasmCompilationUnit::FinishLiftoffCompilation(
     // Consider lifting them both to FinishCompilation.
     native_module_->compiled_module()->source_positions()->set(
         func_index_, *source_positions);
-    return WasmCodeWrapper(native_module_->AddCode(
-        desc, liftoff_.asm_.GetTotalFrameSlotCount(), func_index_,
-        liftoff_.safepoint_table_offset_, protected_instructions_, true));
+    return WasmCodeWrapper(
+        native_module_->AddCode(desc, liftoff_.asm_.GetTotalFrameSlotCount(),
+                                func_index_, liftoff_.safepoint_table_offset_,
+                                std::move(protected_instructions_), true));
   }
 }
 

src/compiler/wasm-compiler.h

@@ -156,7 +156,7 @@ class WasmCompilationUnit final {
   size_t memory_cost_ = 0;
   wasm::NativeModule* native_module_;
   bool lower_simd_;
-  std::shared_ptr<std::vector<trap_handler::ProtectedInstructionData>>
+  std::unique_ptr<std::vector<trap_handler::ProtectedInstructionData>>
       protected_instructions_;
   CompilationMode mode_;
   // {liftoff_} is valid if mode_ == kLiftoff, tf_ if mode_ == kTurbofan.

src/wasm/wasm-code-manager.cc

@@ -387,7 +387,7 @@ WasmCode* NativeModule::AddAnonymousCode(Handle<Code> code,
 WasmCode* NativeModule::AddCode(
     const CodeDesc& desc, uint32_t frame_slots, uint32_t index,
     size_t safepoint_table_offset,
-    std::shared_ptr<ProtectedInstructions> protected_instructions,
+    std::unique_ptr<ProtectedInstructions> protected_instructions,
     bool is_liftoff) {
   std::unique_ptr<byte[]> reloc_info;
   if (desc.reloc_size) {

src/wasm/wasm-code-manager.h

@@ -151,7 +151,7 @@ class V8_EXPORT_PRIVATE WasmCode final {
         constant_pool_offset_(constant_pool_offset),
         stack_slots_(stack_slots),
         safepoint_table_offset_(safepoint_table_offset),
-        protected_instructions_(protected_instructions),
+        protected_instructions_(std::move(protected_instructions)),
         is_liftoff_(is_liftoff) {}
 
   WasmCode(const WasmCode&) = delete;
@@ -190,7 +190,7 @@ class V8_EXPORT_PRIVATE NativeModule final {
 
   WasmCode* AddCode(const CodeDesc& desc, uint32_t frame_count, uint32_t index,
                     size_t safepoint_table_offset,
-                    std::shared_ptr<ProtectedInstructions>,
+                    std::unique_ptr<ProtectedInstructions>,
                     bool is_liftoff = false);
 
   // A way to copy over JS-allocated code. This is because we compile