Replace raw #pragma with portable macros

GIB_PRAGMA will emit build-time messages in the same manner as
before but safely across Clang and GCC.
I had Codex suggest this code, but I did my due diligence and
tested and looked into official docs to ensure the solution
works and actually makes sense.

Author: Noir01

gibbon-rts/rts-c/gibbon_rts.c

@@ -145,7 +145,7 @@ GibSym gib_read_gensym_counter(void)
 #ifdef _GIBBON_POINTER
 
 #ifdef _GIBBON_BUMPALLOC_HEAP
-#pragma message "Using bump allocator."
+GIB_PRAGMA_MESSAGE("Using bump allocator.")
 
 static __thread char *gib_global_ptr_bumpalloc_heap_ptr = (char *) NULL;
 static __thread char *gib_global_ptr_bumpalloc_heap_ptr_end = (char *) NULL;
@@ -512,7 +512,7 @@ GibCursor *gib_array_alloc(GibCursor *arr, size_t size)
         exit(1);
     }
 
-    #pragma GCC unroll 2
+    GIB_PRAGMA_UNROLL(2)
     for (size_t i = 0; i < size; i++){
         arr_on_heap[i] = arr[i];
     }
@@ -724,7 +724,7 @@ double gib_sum_timing_array(GibVector *times)
 
 #ifdef _GIBBON_BUMPALLOC_LISTS
 // #define _GIBBON_DEBUG
-#pragma message "Using bump allocator."
+GIB_PRAGMA_MESSAGE("Using bump allocator.")
 
 static __thread char *gib_global_list_bumpalloc_heap_ptr = (char *) NULL;
 static __thread char *gib_global_list_bumpalloc_heap_ptr_end = (char *) NULL;
@@ -1054,26 +1054,26 @@ void gib_print_gc_config(void) {
     printf("C config\n~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n");
 
 #if defined _GIBBON_GENGC && _GIBBON_GENGC == 0
-    #pragma message "Generational GC is disabled."
+    GIB_PRAGMA_MESSAGE("Generational GC is disabled.")
     printf("Generational GC is disabled.\n");
 #else
-    #pragma message "Generational GC is enabled."
+    GIB_PRAGMA_MESSAGE("Generational GC is enabled.")
     printf("Generational GC is enabled.\n");
 #endif
 
 #if defined _GIBBON_EAGER_PROMOTION && _GIBBON_EAGER_PROMOTION == 0
-    #pragma message "Eager promotion is disabled."
+    GIB_PRAGMA_MESSAGE("Eager promotion is disabled.")
     printf("Eager promotion is disabled.\n");
 #else
-    #pragma message "Eager promotion is enabled."
+    GIB_PRAGMA_MESSAGE("Eager promotion is enabled.")
     printf("Eager promotion is enabled.\n");
 #endif
 
 #if defined _GIBBON_SIMPLE_WRITE_BARRIER && _GIBBON_SIMPLE_WRITE_BARRIER == 0
-    #pragma message "Simple write barrier is disabled."
+    GIB_PRAGMA_MESSAGE("Simple write barrier is disabled.")
     printf("Simple write barrier is disabled.\n");
 #else
-    #pragma message "Simple write barrier is enabled."
+    GIB_PRAGMA_MESSAGE("Simple write barrier is enabled.")
     printf("Simple write barrier is enabled.\n");
 #endif
 

gibbon-rts/rts-c/gibbon_rts.h

@@ -15,6 +15,25 @@
 #include <cilk/cilk_api.h>
 #endif
 
+#define GIB_PRAGMA(x) _Pragma(#x)
+
+#if defined(__clang__)
+#define GIB_PRAGMA_MESSAGE(msg)        \
+    GIB_PRAGMA(clang diagnostic push)  \
+    GIB_PRAGMA(clang diagnostic ignored "-W#pragma-messages") \
+    GIB_PRAGMA(message msg)            \
+    GIB_PRAGMA(clang diagnostic pop)
+#else
+#define GIB_PRAGMA_MESSAGE(msg) GIB_PRAGMA(message msg)
+#endif
+
+#if defined(__clang__)
+#define GIB_PRAGMA_UNROLL(n) GIB_PRAGMA(unroll n)
+#elif defined(__GNUC__) && (__GNUC__ >= 8)
+#define GIB_PRAGMA_UNROLL(n) GIB_PRAGMA(GCC unroll n)
+#else
+#define GIB_PRAGMA_UNROLL(n)
+#endif
 /*
  * CPP macros used in the RTS:
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -358,7 +377,7 @@ extern bool gib_global_thread_requested_gc;
 
 extern uint64_t gib_global_num_threads;
 
-INLINE_HEADER GibThreadId gib_get_thread_id()
+INLINE_HEADER GibThreadId gib_get_thread_id(void)
 {
 #ifdef _GIBBON_PARALLEL
     return __cilkrts_get_worker_number();
@@ -1083,9 +1102,9 @@ INLINE_HEADER void gib_indirection_barrier(
 {
 
 #if defined _GIBBON_SIMPLE_WRITE_BARRIER && _GIBBON_SIMPLE_WRITE_BARRIER == 1
-    #pragma message "Simple write barrier is enabled."
+    GIB_PRAGMA_MESSAGE("Simple write barrier is enabled.")
 #else
-    #pragma message "Simple write barrier is disabled."
+    GIB_PRAGMA_MESSAGE("Simple write barrier is disabled.")
     {
         // Optimization: don't create long chains of indirection pointers.
         GibPackedTag pointed_to_tag = *(GibPackedTag *) to;
@@ -1219,12 +1238,12 @@ INLINE_HEADER uint8_t gib_log2(size_t x)
 
 // From Chandler Carruth's CppCon 2015 talk.
 INLINE_HEADER void escape(void *p) {
-    asm volatile("" : : "g"(p) : "memory");
+    __asm__ __volatile__("" : : "g"(p) : "memory");
 }
 
 // From Chandler Carruth's CppCon 2015 talk.
-INLINE_HEADER void clobber() {
-    asm volatile("" : : : "memory");
+INLINE_HEADER void clobber(void) {
+    __asm__ __volatile__("" : : : "memory");
 }