add makeEpilog and close is called only once at most.

test/Makefile

@@ -1,7 +1,7 @@
 # To compile with -m32
 # apt install g++-multilib
 TARGET = make_nm normalize_prefix bad_address misc cvt_test cvt_test32 noexception misc32 detect_x32 avx10_test
-XBYAK_INC=../xbyak/xbyak.h ../xbyak/xbyak_mnemonic.h
+XBYAK_INC=../xbyak/xbyak.h ../xbyak/xbyak_mnemonic.h ../xbyak/xbyak_util.h
 UNAME_S=$(shell uname -s)
 ifeq ($(shell ./detect_x32),x32)
 X32?=1

test/sf_test.cpp

@@ -389,3 +389,61 @@ CYBOZU_TEST_AUTO(pack)
 	}
 }
 
+struct CloseCode : Xbyak::CodeGenerator {
+	CloseCode(size_t mode)
+	{
+		switch (mode) {
+		case 0:
+			{
+				StackFrame sf(this, 0);
+				// close() is automatically called.
+			}
+			break;
+
+		case 1:
+			{
+				StackFrame sf(this, 0);
+				sf.close(); // Explicitly call close().
+			}
+			break;
+
+		case 2:
+			{
+				StackFrame sf(this, 0);
+				sf.close();
+				sf.close(); // The second call is ignored.
+			}
+			break;
+
+		case 3:
+			{
+				StackFrame sf(this, 0);
+				sf.makeEpilog(); // Explicitly call makeEpilog.
+				// close() is automatically called.
+			}
+			break;
+
+		case 4:
+			{
+				StackFrame sf(this, 0);
+				sf.makeEpilog(); // Explicitly call makeEpilog.
+				sf.makeEpilog(); // The second call is also valid.
+				// close() is automatically called.
+			}
+			break;
+		default:
+			CYBOZU_TEST_ASSERT(false);
+		}
+	}
+};
+
+CYBOZU_TEST_AUTO(close)
+{
+	const size_t expectedTbl[] = {
+		1, 1, 1, 2, 3,
+	};
+	for (size_t i = 0; i < sizeof(expectedTbl)/sizeof(expectedTbl[0]); i++) {
+		CloseCode c(i);
+		CYBOZU_TEST_EQUAL(c.getSize(), expectedTbl[i]);
+	}
+}

xbyak/xbyak_util.h

@@ -892,17 +892,18 @@ class StackFrame {
 #endif
 	static const int maxRegNum = 14; // maxRegNum = 16 - rsp - rax
 	Xbyak::CodeGenerator *code_;
+	Xbyak::Reg64 pTbl_[4];
+	Xbyak::Reg64 tTbl_[maxRegNum];
+	Pack p_;
+	Pack t_;
 	int pNum_;
 	int tNum_;
-	bool useRcx_;
-	bool useRdx_;
 	int saveNum_;
 	int P_;
+	bool useRcx_;
+	bool useRdx_;
 	bool makeEpilog_;
-	Xbyak::Reg64 pTbl_[4];
-	Xbyak::Reg64 tTbl_[maxRegNum];
-	Pack p_;
-	Pack t_;
+	bool closed_;
 	StackFrame(const StackFrame&);
 	void operator=(const StackFrame&);
 public:
@@ -928,11 +929,12 @@ class StackFrame {
 		: code_(code)
 		, pNum_(pNum)
 		, tNum_(tNum & ~(UseRCX | UseRDX))
-		, useRcx_((tNum & UseRCX) != 0)
-		, useRdx_((tNum & UseRDX) != 0)
 		, saveNum_(0)
 		, P_(0)
+		, useRcx_((tNum & UseRCX) != 0)
+		, useRdx_((tNum & UseRDX) != 0)
 		, makeEpilog_(makeEpilog)
+		, closed_(false)
 		, p(p_)
 		, t(t_)
 	{
@@ -966,7 +968,7 @@ class StackFrame {
 		make epilog manually
 		@param callRet [in] call ret() if true
 	*/
-	void close(bool callRet = true)
+	void makeEpilog(bool callRet = true)
 	{
 		using namespace Xbyak;
 		const Reg64& _rsp = code_->rsp;
@@ -978,6 +980,14 @@ class StackFrame {
 
 		if (callRet) code_->ret();
 	}
+	// close() is automatically called in a destructor.
+	// It is not called if close() is explicitly called before.
+	void close(bool callRet = true)
+	{
+		if (closed_) return;
+		makeEpilog(callRet);
+		closed_ = true;
+	}
 	~StackFrame()
 	{
 		if (!makeEpilog_) return;