From c745df94a182b8a569cb833ecfbe8da33bf01f98 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Thu, 9 Nov 2023 14:34:21 -0500
Subject: config: New attr_noinline and attr_cold macros

---
 src/alloc.c  |  1 +
 src/config.h | 18 ++++++++++++++++++
 src/diag.h   | 15 +++++++++++++++
 src/ioq.c    |  2 ++
 4 files changed, 36 insertions(+)

diff --git a/src/alloc.c b/src/alloc.c
index 0b978ba..3b9972f 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -107,6 +107,7 @@ void arena_init(struct arena *arena, size_t align, size_t size) {
 }
 
 /** Allocate a new slab. */
+attr_cold
 static int slab_alloc(struct arena *arena) {
 	void **slabs = realloc(arena->slabs, sizeof_array(void *, arena->nslabs + 1));
 	if (!slabs) {
diff --git a/src/config.h b/src/config.h
index 3100cec..b95abaa 100644
--- a/src/config.h
+++ b/src/config.h
@@ -184,6 +184,24 @@
 #  define fallthru ((void)0)
 #endif
 
+/**
+ * Hint to avoid inlining a function.
+ */
+#if __has_attribute(noinline)
+#  define attr_noinline __attribute__((noinline))
+#else
+#  define attr_noinline
+#endif
+
+/**
+ * Hint that a function is unlikely to be called.
+ */
+#if __has_attribute(cold)
+#  define attr_cold attr_noinline __attribute__((cold))
+#else
+#  define attr_cold attr_noinline
+#endif
+
 /**
  * Adds compiler warnings for bad printf()-style function calls, if supported.
  */
diff --git a/src/diag.h b/src/diag.h
index 8c7ed57..870264e 100644
--- a/src/diag.h
+++ b/src/diag.h
@@ -44,6 +44,7 @@ struct bfs_loc {
 /**
  * Print a message to standard error and abort.
  */
+attr_cold
 attr_format(2, 3)
 noreturn void bfs_abortf(const struct bfs_loc *loc, const char *format, ...);
 
@@ -116,11 +117,13 @@ const char *debug_flag_name(enum debug_flags flag);
 /**
  * Like perror(), but decorated like bfs_error().
  */
+attr_cold
 void bfs_perror(const struct bfs_ctx *ctx, const char *str);
 
 /**
  * Shorthand for printing error messages.
  */
+attr_cold
 attr_format(2, 3)
 void bfs_error(const struct bfs_ctx *ctx, const char *format, ...);
 
@@ -129,6 +132,7 @@ void bfs_error(const struct bfs_ctx *ctx, const char *format, ...);
  *
  * @return Whether a warning was printed.
  */
+attr_cold
 attr_format(2, 3)
 bool bfs_warning(const struct bfs_ctx *ctx, const char *format, ...);
 
@@ -137,60 +141,71 @@ bool bfs_warning(const struct bfs_ctx *ctx, const char *format, ...);
  *
  * @return Whether a debug message was printed.
  */
+attr_cold
 attr_format(3, 4)
 bool bfs_debug(const struct bfs_ctx *ctx, enum debug_flags flag, const char *format, ...);
 
 /**
  * bfs_error() variant that takes a va_list.
  */
+attr_cold
 attr_format(2, 0)
 void bfs_verror(const struct bfs_ctx *ctx, const char *format, va_list args);
 
 /**
  * bfs_warning() variant that takes a va_list.
  */
+attr_cold
 attr_format(2, 0)
 bool bfs_vwarning(const struct bfs_ctx *ctx, const char *format, va_list args);
 
 /**
  * bfs_debug() variant that takes a va_list.
  */
+attr_cold
 attr_format(3, 0)
 bool bfs_vdebug(const struct bfs_ctx *ctx, enum debug_flags flag, const char *format, va_list args);
 
 /**
  * Print the error message prefix.
  */
+attr_cold
 void bfs_error_prefix(const struct bfs_ctx *ctx);
 
 /**
  * Print the warning message prefix.
  */
+attr_cold
 bool bfs_warning_prefix(const struct bfs_ctx *ctx);
 
 /**
  * Print the debug message prefix.
  */
+attr_cold
 bool bfs_debug_prefix(const struct bfs_ctx *ctx, enum debug_flags flag);
 
 /**
  * Highlight parts of the command line in an error message.
  */
+attr_cold
 void bfs_argv_error(const struct bfs_ctx *ctx, const bool args[]);
 
 /**
  * Highlight parts of an expression in an error message.
  */
+attr_cold
 void bfs_expr_error(const struct bfs_ctx *ctx, const struct bfs_expr *expr);
 
 /**
  * Highlight parts of the command line in a warning message.
  */
+attr_cold
 bool bfs_argv_warning(const struct bfs_ctx *ctx, const bool args[]);
 
 /**
  * Highlight parts of an expression in a warning message.
  */
+attr_cold
 bool bfs_expr_warning(const struct bfs_ctx *ctx, const struct bfs_expr *expr);
 
 #endif // BFS_DIAG_H
diff --git a/src/ioq.c b/src/ioq.c
index 244b2cc..ef89fa8 100644
--- a/src/ioq.c
+++ b/src/ioq.c
@@ -269,6 +269,7 @@ static struct ioq_monitor *ioq_slot_monitor(struct ioqq *ioqq, ioq_slot *slot) {
 }
 
 /** Atomically wait for a slot to change. */
+attr_noinline
 static uintptr_t ioq_slot_wait(struct ioqq *ioqq, ioq_slot *slot, uintptr_t value) {
 	struct ioq_monitor *monitor = ioq_slot_monitor(ioqq, slot);
 	mutex_lock(&monitor->mutex);
@@ -298,6 +299,7 @@ done:
 }
 
 /** Wake up any threads waiting on a slot. */
+attr_noinline
 static void ioq_slot_wake(struct ioqq *ioqq, ioq_slot *slot) {
 	struct ioq_monitor *monitor = ioq_slot_monitor(ioqq, slot);
 
-- 
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