cpp: Use #pragma once instead of #ifndef guards
[ghc.git] / rts / sm / Evac.h
1 /* -----------------------------------------------------------------------------
2 *
3 * (c) The GHC Team 1998-2008
4 *
5 * Generational garbage collector: evacuation functions
6 *
7 * Documentation on the architecture of the Garbage Collector can be
8 * found in the online commentary:
9 *
10 * http://ghc.haskell.org/trac/ghc/wiki/Commentary/Rts/Storage/GC
11 *
12 * ---------------------------------------------------------------------------*/
13
14 #pragma once
15
16 #include "BeginPrivate.h"
17
18 // Use a register argument for evacuate, if available.
19 // Earlier, the regparm attribute was used whenever __GNUC__ >= 2, but this
20 // generated warnings on PPC. So the use is restricted further.
21 // See http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html that says
22 // regparm (number)
23 // On the Intel 386, the regparm attribute causes the compiler to pass
24 // arguments number one to number if they are of integral type in
25 // registers EAX, EDX, and ECX instead of on the stack. Functions that
26 // take a variable number of arguments will continue to be passed all of
27 // their arguments on the stack.
28 #if __GNUC__ >= 2 && (defined(x86_64_HOST_ARCH) || defined(i386_HOST_ARCH))
29 #define REGPARM1 __attribute__((regparm(1)))
30 #else
31 #define REGPARM1
32 #endif
33
34 REGPARM1 void evacuate (StgClosure **p);
35 REGPARM1 void evacuate1 (StgClosure **p);
36
37 extern W_ thunk_selector_depth;
38
39 #include "EndPrivate.h"