elog_ereport_attribute_cold.patch

diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index e976201030..8076e8af24 100644
--- a/src/backend/utils/error/elog.c
+++ b/src/backend/utils/error/elog.c
@@ -219,6 +219,19 @@ err_gettext(const char *str)
 #endif
 }
 
+#if defined(HAVE_PG_ATTRIBUTE_HOT_AND_COLD) && defined(HAVE__BUILTIN_CONSTANT_P)
+/*
+ * errstart_cold
+ *		A simple wrapper around errstart, but hinted to be cold so that the
+ *		compiler is more likely to put error code in a cold area away from the
+ *		main function body.
+ */
+bool
+pg_attribute_cold errstart_cold(int elevel, const char *domain)
+{
+	return errstart(elevel, domain);
+}
+#endif
 
 /*
  * errstart --- begin an error-reporting cycle
diff --git a/src/include/c.h b/src/include/c.h
index d72b23afe4..087b8af6cb 100644
--- a/src/include/c.h
+++ b/src/include/c.h
@@ -178,6 +178,21 @@
 #define pg_noinline
 #endif
 
+/*
+ * Marking certain functions as "hot" or "cold" can be useful to assist the
+ * compiler in arranging the assembly code in a more efficient way.
+ * These are supported from GCC >= 4.3 and clang >= 3.2
+ */
+#if (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3))) || \
+	(defined(__clang__) && (__clang_major__ > 3 || (__clang_major__ == 3 && __clang_minor__ >= 2)))
+#define HAVE_PG_ATTRIBUTE_HOT_AND_COLD 1
+#define pg_attribute_hot __attribute__((hot))
+#define pg_attribute_cold __attribute__((cold))
+#else
+#define pg_attribute_hot
+#define pg_attribute_cold
+#endif
+
 /*
  * Mark a point as unreachable in a portable fashion.  This should preferably
  * be something that the compiler understands, to aid code generation.
diff --git a/src/include/utils/elog.h b/src/include/utils/elog.h
index 1e09ee0541..97fb4d74d2 100644
--- a/src/include/utils/elog.h
+++ b/src/include/utils/elog.h
@@ -121,6 +121,18 @@
  *----------
  */
 #ifdef HAVE__BUILTIN_CONSTANT_P
+#ifdef HAVE_PG_ATTRIBUTE_HOT_AND_COLD
+#define ereport_domain(elevel, domain, ...)	\
+	do { \
+		pg_prevent_errno_in_scope(); \
+		if (__builtin_constant_p(elevel) && (elevel) >= ERROR ? \
+			 errstart_cold(elevel, domain) : \
+			 errstart(elevel, domain)) \
+			__VA_ARGS__, errfinish(__FILE__, __LINE__, PG_FUNCNAME_MACRO); \
+		if (__builtin_constant_p(elevel) && (elevel) >= ERROR) \
+			pg_unreachable(); \
+	} while(0)
+#else							/* !HAVE_PG_ATTRIBUTE_HOT_AND_COLD */
 #define ereport_domain(elevel, domain, ...)	\
 	do { \
 		pg_prevent_errno_in_scope(); \
@@ -129,6 +141,7 @@
 		if (__builtin_constant_p(elevel) && (elevel) >= ERROR) \
 			pg_unreachable(); \
 	} while(0)
+#endif							/* HAVE_PG_ATTRIBUTE_HOT_AND_COLD */
 #else							/* !HAVE__BUILTIN_CONSTANT_P */
 #define ereport_domain(elevel, domain, ...)	\
 	do { \
@@ -146,6 +159,9 @@
 
 #define TEXTDOMAIN NULL
 
+#ifdef HAVE_PG_ATTRIBUTE_HOT_AND_COLD
+extern bool pg_attribute_cold errstart_cold(int elevel, const char *domain);
+#endif
 extern bool errstart(int elevel, const char *domain);
 extern void errfinish(const char *filename, int lineno, const char *funcname);