[stubs] Ensure CSA_ASSERT and CSA_SLOW_ASSERT do not produce unused instructions in release mode.

src/code-stub-assembler.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_CODE_STUB_ASSEMBLER_H_
 #define V8_CODE_STUB_ASSEMBLER_H_
 
 #include <functional>
 
 #include "src/compiler/code-assembler.h"
@@ skipping 143 matching lines @@
   compiler::Node* NumberInc(compiler::Node* value);
 
   // Allocate an object of the given size.
   compiler::Node* Allocate(compiler::Node* size, AllocationFlags flags = kNone);
   compiler::Node* Allocate(int size, AllocationFlags flags = kNone);
   compiler::Node* InnerAllocate(compiler::Node* previous, int offset);
   compiler::Node* InnerAllocate(compiler::Node* previous,
                                 compiler::Node* offset);
   compiler::Node* IsRegularHeapObjectSize(compiler::Node* size);
 
-  void Assert(compiler::Node* condition, const char* string = nullptr,
+  typedef std::function<compiler::Node*()> ConditionBody;
+  void Assert(ConditionBody condition_body, const char* string = nullptr,
               const char* file = nullptr, int line = 0);
+  void SlowAssert(ConditionBody condition_body, const char* string = nullptr,
+                  const char* file = nullptr, int line = 0);
+  // No-op. Used by CSA_ASSERT macro.
+  inline void Nop() {}
 
   // Check a value for smi-ness
   compiler::Node* TaggedIsSmi(compiler::Node* a);
   // Check that the value is a non-negative smi.
   compiler::Node* WordIsPositiveSmi(compiler::Node* a);
   // Check that a word has a word-aligned address.
   compiler::Node* WordIsWordAligned(compiler::Node* word);
   compiler::Node* WordIsPowerOfTwo(compiler::Node* value);
 
   void BranchIfSmiEqual(compiler::Node* a, compiler::Node* b, Label* if_true,
@@ skipping 1074 matching lines @@
 
  private:
   compiler::Node* GetArguments();
 
   CodeStubAssembler* assembler_;
   compiler::Node* argc_;
   compiler::Node* arguments_;
   compiler::Node* fp_;
 };
 
-#define CSA_ASSERT(x) Assert((x), #x, __FILE__, __LINE__)
+#ifdef DEBUG
+#define CSA_ASSERT(x) Assert([&] { return (x); }, #x, __FILE__, __LINE__)

[Benedikt Meurer, 2016/11/09 04:52:09]

Can we please, please find a less awkward syntax for this? How about not having
this terrible macro at all, and just using the higher-order Assert function, and
have that generate code only in debug mode?

[Igor Sheludko, 2016/11/09 12:10:34]

Ok, I can remove this lambda code.

+#else
+#define CSA_ASSERT(x) Nop()
+#endif
+
 #ifdef ENABLE_SLOW_DCHECKS
-#define CSA_SLOW_ASSERT(x)               \
-  if (FLAG_enable_slow_asserts) {        \
-    Assert((x), #x, __FILE__, __LINE__); \
-  }
+#define CSA_SLOW_ASSERT(x) \
+  SlowAssert([&] { return (x); }, #x, __FILE__, __LINE__)
 #else
-#define CSA_SLOW_ASSERT(x)
+#define CSA_SLOW_ASSERT(x) Nop()
 #endif
 
 DEFINE_OPERATORS_FOR_FLAGS(CodeStubAssembler::AllocationFlags);
 
 }  // namespace internal
 }  // namespace v8
 #endif  // V8_CODE_STUB_ASSEMBLER_H_