Revert of [wasm] Master CL for Binary 0xC changes.

src/wasm/wasm-interpreter.h

 // Copyright 2016 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.
 
 #ifndef V8_WASM_INTERPRETER_H_
 #define V8_WASM_INTERPRETER_H_
 
 #include "src/wasm/wasm-opcodes.h"
 #include "src/zone/zone-containers.h"
 
@@ skipping 10 matching lines @@
 struct WasmModuleInstance;
 class WasmInterpreterInternals;
 
 typedef size_t pc_t;
 typedef size_t sp_t;
 typedef int32_t pcdiff_t;
 typedef uint32_t spdiff_t;
 
 const pc_t kInvalidPc = 0x80000000;
 
-typedef ZoneMap<pc_t, pcdiff_t> ControlTransferMap;
+// Visible for testing. A {ControlTransfer} helps the interpreter figure out
+// the target program counter and stack manipulations for a branch.
+struct ControlTransfer {
+  enum StackAction { kNoAction, kPopAndRepush, kPushVoid };
+  pcdiff_t pcdiff;  // adjustment to the program counter (positive or negative).
+  spdiff_t spdiff;  // number of elements to pop off the stack.
+  StackAction action;  // action to perform on the stack.
+};
+typedef ZoneMap<pc_t, ControlTransfer> ControlTransferMap;
 
 // Macro for defining union members.
 #define FOREACH_UNION_MEMBER(V) \
   V(i32, kAstI32, int32_t)      \
   V(u32, kAstI32, uint32_t)     \
   V(i64, kAstI64, int64_t)      \
   V(u64, kAstI64, uint64_t)     \
   V(f32, kAstF32, float)        \
   V(f64, kAstF64, double)
 
@@ skipping 75 matching lines @@
     virtual State Step() = 0;
     virtual void Pause() = 0;
     virtual void Reset() = 0;
     virtual ~Thread() {}
 
     // Stack inspection and modification.
     virtual pc_t GetBreakpointPc() = 0;
     virtual int GetFrameCount() = 0;
     virtual const WasmFrame* GetFrame(int index) = 0;
     virtual WasmFrame* GetMutableFrame(int index) = 0;
-    virtual WasmVal GetReturnValue(int index = 0) = 0;
+    virtual WasmVal GetReturnValue() = 0;
 
     // Thread-specific breakpoints.
     bool SetBreakpoint(const WasmFunction* function, int pc, bool enabled);
     bool GetBreakpoint(const WasmFunction* function, int pc);
   };
 
   WasmInterpreter(WasmModuleInstance* instance, AccountingAllocator* allocator);
   ~WasmInterpreter();
 
   //==========================================================================
@@ skipping 36 matching lines @@
   //==========================================================================
   // Testing functionality.
   //==========================================================================
   // Manually adds a function to this interpreter, returning the index of the
   // function.
   int AddFunctionForTesting(const WasmFunction* function);
   // Manually adds code to the interpreter for the given function.
   bool SetFunctionCodeForTesting(const WasmFunction* function,
                                  const byte* start, const byte* end);
 
-  // Computes the control transfers for the given bytecode. Used internally in
-  // the interpreter, but exposed for testing.
+  // Computes the control targets for the given bytecode as {pc offset, sp
+  // offset}
+  // pairs. Used internally in the interpreter, but exposed for testing.
   static ControlTransferMap ComputeControlTransfersForTesting(Zone* zone,
                                                               const byte* start,
                                                               const byte* end);
 
  private:
   Zone zone_;
   WasmInterpreterInternals* internals_;
 };
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_WASM_INTERPRETER_H_