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

src/code-stub-assembler.h

Index: src/code-stub-assembler.h
diff --git a/src/code-stub-assembler.h b/src/code-stub-assembler.h
index 36e7801bdd188c082a16e0a29e594835e56a8741..0ec3ce41ce9b06f461ebbf4fc7e181d650d632b4 100644
--- a/src/code-stub-assembler.h
+++ b/src/code-stub-assembler.h
@@ -161,8 +161,13 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
                                 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);
@@ -1257,14 +1262,17 @@ class CodeStubArguments {
   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);