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

src/compiler/x64/code-generator-x64.cc

 // Copyright 2013 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/code-generator.h"
 
 #include <limits>
 
 #include "src/compilation-info.h"
 #include "src/compiler/code-generator-impl.h"
@@ skipping 252 matching lines @@
   Register const object_;
   Operand const operand_;
   Register const value_;
   Register const scratch0_;
   Register const scratch1_;
   RecordWriteMode const mode_;
 };
 
 class WasmOutOfLineTrap final : public OutOfLineCode {
  public:
-  WasmOutOfLineTrap(CodeGenerator* gen, Address pc, bool frame_elided,
+  WasmOutOfLineTrap(CodeGenerator* gen, int pc, bool frame_elided,
                     Register context, int32_t position)
       : OutOfLineCode(gen),
+        gen_(gen),
         pc_(pc),
         frame_elided_(frame_elided),
         context_(context),
         position_(position) {}
 
   void Generate() final {

[titzer, 2016/11/30 17:31:12]

We should probably refactor this method to take the code generator as a
parameter. Can you leave a TODO here?

[Eric Holk, 2016/11/30 20:16:19]

Done.

-    // TODO(eholk): record pc_ and the current pc in a table so that
-    // the signal handler can find it.
-    USE(pc_);
+    int current_pc = __ pc_offset();
+
+    gen_->AddProtectedInstruction(pc_, current_pc);
 
     if (frame_elided_) {
       __ EnterFrame(StackFrame::WASM);
     }
 
     wasm::TrapReason trap_id = wasm::kTrapMemOutOfBounds;
     int trap_reason = wasm::WasmOpcodes::TrapReasonToMessageId(trap_id);
     __ Push(Smi::FromInt(trap_reason));
     __ Push(Smi::FromInt(position_));
     __ Move(rsi, context_);
     __ CallRuntime(Runtime::kThrowWasmError);
   }
 
  private:
-  Address pc_;
+  CodeGenerator* gen_;
+  int pc_;
   bool frame_elided_;
   Register context_;
   int32_t position_;
 };
 
 }  // namespace
 
 
 #define ASSEMBLE_UNOP(asm_instr)         \
   do {                                   \
@@ skipping 1580 matching lines @@
     case kX64Movl:
     case kX64TrapMovl:
       if (instr->HasOutput()) {
         if (instr->addressing_mode() == kMode_None) {
           if (instr->InputAt(0)->IsRegister()) {
             __ movl(i.OutputRegister(), i.InputRegister(0));
           } else {
             __ movl(i.OutputRegister(), i.InputOperand(0));
           }
         } else {
-          Address pc = __ pc();
+          int pc = __ pc_offset();
           __ movl(i.OutputRegister(), i.MemoryOperand());
 
           if (arch_opcode == kX64TrapMovl) {
             bool frame_elided = !frame_access_state()->has_frame();
             new (zone()) WasmOutOfLineTrap(this, pc, frame_elided,
                                            i.InputRegister(2), i.InputInt32(3));
           }
         }
         __ AssertZeroExtended(i.OutputRegister());
       } else {
@@ skipping 866 matching lines @@
     int padding_size = last_lazy_deopt_pc_ + space_needed - current_pc;
     __ Nop(padding_size);
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8