[wasm] OOB traps: build protected instruction list during codegen

src/compiler/wasm-compiler.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/wasm-compiler.h"
 
 #include <memory>
 
 #include "src/isolate-inl.h"
 
@@ skipping 3372 matching lines @@
                        graph_zone(), MachineType::PointerRepresentation(),
                        InstructionSelector::SupportedMachineOperatorFlags(),
                        InstructionSelector::AlignmentRequirements()))),
       compilation_zone_(isolate->allocator(), ZONE_NAME),
       info_(function->name_length != 0 ? module_env->GetNameOrNull(function)
                                        : ArrayVector("wasm"),
             isolate, &compilation_zone_,
             Code::ComputeFlags(Code::WASM_FUNCTION)),
       job_(),
       index_(index),
-      ok_(true) {
+      ok_(true),
+      protected_instructions_(&compilation_zone_) {
   // Create and cache this node in the main thread.
   jsgraph_->CEntryStubConstant(1);
 }
 
 void WasmCompilationUnit::ExecuteCompilation() {
   // TODO(ahaas): The counters are not thread-safe at the moment.
   //    HistogramTimerScope wasm_compile_function_time_scope(
   //        isolate_->counters()->wasm_compile_function_time());
   if (FLAG_trace_wasm_compiler) {
     OFStream os(stdout);
@@ skipping 20 matching lines @@
   }
 
   // Run the compiler pipeline to generate machine code.
   CallDescriptor* descriptor = wasm::ModuleEnv::GetWasmCallDescriptor(
       &compilation_zone_, function_->sig);
   if (jsgraph_->machine()->Is32()) {
     descriptor =
         module_env_->GetI32WasmCallDescriptor(&compilation_zone_, descriptor);
   }
   job_.reset(Pipeline::NewWasmCompilationJob(&info_, jsgraph_, descriptor,
-                                             source_positions));
+                                             source_positions,
+                                             &protected_instructions_));
   ok_ = job_->ExecuteJob() == CompilationJob::SUCCEEDED;
   // TODO(bradnelson): Improve histogram handling of size_t.
   // TODO(ahaas): The counters are not thread-safe at the moment.
   //    isolate_->counters()->wasm_compile_function_peak_memory_bytes()
   // ->AddSample(
   //        static_cast<int>(jsgraph->graph()->zone()->allocation_size()));
 
   if (FLAG_trace_wasm_decode_time) {
     double pipeline_ms = pipeline_timer.Elapsed().InMillisecondsF();
     PrintF(
@@ skipping 37 matching lines @@
   }
 
   if (FLAG_trace_wasm_decode_time) {
     double compile_ms = compile_timer.Elapsed().InMillisecondsF();
     PrintF("wasm-code-generation ok: %d bytes, %0.3f ms code generation\n",
            static_cast<int>(function_->code_end_offset -
                             function_->code_start_offset),
            compile_ms);
   }
 
+  Handle<FixedArray> protected_instructions = PackProtectedInstructions();
+  code->set_protected_instructions(*protected_instructions);
+
   return code;
 }
 
+Handle<FixedArray> WasmCompilationUnit::PackProtectedInstructions() const {
+  const int num_instructions = static_cast<int>(protected_instructions_.size());
+  Handle<FixedArray> fn_protected = isolate_->factory()->NewFixedArray(
+      num_instructions * Code::kTrapDataSize, TENURED);
+  for (unsigned i = 0; i < protected_instructions_.size(); ++i) {
+    const trap_handler::ProtectedInstructionData& instruction =
+        protected_instructions_[i];
+    fn_protected->set(Code::kTrapDataSize * i + Code::kTrapCodeOffset,
+                      Smi::FromInt(instruction.instr_offset));
+    fn_protected->set(Code::kTrapDataSize * i + Code::kTrapLandingOffset,
+                      Smi::FromInt(instruction.landing_offset));
+  }
+  return fn_protected;
+}
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8