Added likeliness annotations to some nullptr checks

Fortune for cpprng's current commit: Great blessing − 大吉

Makefile

@@ -9,7 +9,7 @@ SRC_CXX = $(wildcard src/*.cpp) $(wildcard src/rng/*.cpp)
 
 INCLUDE=include
 
-COMMON_FLAGS= -W -Wall -pedantic -fno-strict-aliasing $(addprefix -I,$(INCLUDE))
+COMMON_FLAGS+= -W -Wall -pedantic -fno-strict-aliasing $(addprefix -I,$(INCLUDE))
 
 OPT_FLAGS?= -march=native -fgraphite -fopenmp -floop-parallelize-all -ftree-parallelize-loops=4 \
 	    -floop-interchange -ftree-loop-distribution -floop-strip-mine -floop-block \
@@ -32,7 +32,7 @@ ifneq ($(TARGET_SPEC_FLAGS),no)
 	RELEASE_LDFLAGS?=  -Wl,-O3 -Wl,-flto
 
 	DEBUG_CFLAGS?=	-Og -g
-	DEBUG_CXXFLAGS?=-O0 -g
+	DEBUG_CXXFLAGS?=-Og -g
 	DEBUG_LDFLAGS?=
 endif
 

include/common.h

@@ -15,6 +15,9 @@ extern "C" {
 #define IFUNC_RESOLVER(name)  IFUNC_RESOLVER_A((copy(name)), name)
 #define IFUNC_DEF(name, params) name params __attribute__((__ifunc__("_ifun__" #name)))
 
+#define LIKELY(expr)   __builtin_expect(!!(expr), 1)
+#define UNLIKELY(expr) __builtin_expect(!!(expr), 0)
+
 #define _export(kind) __attribute__((visibility(#kind)))
 #define v_internal	_export(internal)
 #define v_protected	_export(protected)

src/aligned_ptr.cpp

@@ -2,12 +2,13 @@
 
 #include <cstdlib>
 
+#include <common.h>
 #include <mem.h>
 
 template<typename T>
 static inline T* not_null(T* ptr)
 {
-	if(!ptr) throw "TODO: Nullptr except";
+	if(UNLIKELY(!ptr)) throw "TODO: Nullptr except";
 	return ptr;
 }
 

src/rng/crand.c

@@ -32,20 +32,25 @@ typedef __typeof(((struct jr_state*)NULL)->st) jr_xsub_t;
 _Static_assert( sizeof(uint48_t) == (sizeof(uint16_t) * 3), "bad uint48 (ushort[3])");
 _Static_assert( sizeof(((struct jr_state*)NULL)->st) == sizeof(uint64_t), "bad uint64 (union st)");
 
-static unsigned short* IFUNC_DEF(_jr_st_resolv, (jr_xsub_t* restrict state)
+inline static unsigned short* IFUNC_DEF(_jr_st_resolv, (jr_xsub_t* restrict state)
 	__attribute__((const, nonnull, returns_nonnull)));
 
-static unsigned short* IFUNC_IMPL(_jr_st_resolv, low) (jr_xsub_t* restrict state)
+inline static unsigned short* IFUNC_IMPL(_jr_st_resolv, low) (jr_xsub_t* restrict state)
 {
 	return state->xsubi;
 }
-static unsigned short* IFUNC_IMPL(_jr_st_resolv, high) (jr_xsub_t* restrict state)
+inline static unsigned short* IFUNC_IMPL(_jr_st_resolv, high) (jr_xsub_t* restrict state)
 {
 	return state->xsubi+1;
 }
 __attribute__((const))
-static unsigned short* IFUNC_RESOLVER(_jr_st_resolv) (jr_xsub_t* restrict state)
+inline static unsigned short* IFUNC_RESOLVER(_jr_st_resolv) (jr_xsub_t* restrict state)
 {
+	// This ifunc is free.
+	// The optimiser recognises the return value of this function at compile time, and discards the unused function, removing the need for any runtime ifunc resolution.
+	// The ifunc `_jr_st_resolv()` is essentially (almost) the same as a symbol-aliased constexpr function.
+	// Ain't that neat?
+
 	struct jr_state chk = {0};
 	chk.st.xsubh = JR_MAX;
 	return chk.st._xsub 
@@ -75,6 +80,8 @@ __attribute__((malloc(_jr_free)))
 internal struct jr_state* _jr_alloc()
 {
 	struct jr_state* bx = aligned_alloc(_Alignof(struct jr_state), sizeof(struct jr_state));
+	if(UNLIKELY(!bx)) return NULL;
+
 	memset(bx, 0, sizeof(struct jr_state));
 
 	return bx;
@@ -83,12 +90,15 @@ __attribute__((malloc(_jr_free)))
 internal struct jr_state* _jr_new(unsigned long with)
 {
 	struct jr_state* state = _jr_alloc();
+	if(UNLIKELY(!state)) return NULL;
+
 	_jr_seed(state, with);
 	return state;
 }
 
 internal void _jr_free(struct jr_state* restrict state)
 {
+	if(LIKELY(state))
 		free(state);
 }