cpp: Use #pragma once instead of #ifndef guards

This both says what we mean and silences a bunch of spurious CPP linting
warnings. This pragma is supported by all CPP implementations which we
support.

Reviewers: austin, erikd, simonmar, hvr

Reviewed By: simonmar

Subscribers: rwbarton, thomie

Differential Revision: https://phabricator.haskell.org/D3482

7 files changed, 7 insertions, 27 deletions

diff --git a/rts/linker/CacheFlush.h b/rts/linker/CacheFlush.h
index f4d939d21e..aa081cca29 100644
--- a/rts/linker/CacheFlush.h
+++ b/rts/linker/CacheFlush.h
@@ -1,5 +1,4 @@
-#ifndef CACHE_FLUSH_H
-#define CACHE_FLUSH_H
+#pragma once
 
 #include "LinkerInternals.h"
 
@@ -8,5 +7,3 @@
 void ocFlushInstructionCache( ObjectCode *oc );
 
 #include "EndPrivate.h"
-
-#endif /* CACHE_FLUSH_H */
diff --git a/rts/linker/Elf.h b/rts/linker/Elf.h
index 0c33130122..57ec46e146 100644
--- a/rts/linker/Elf.h
+++ b/rts/linker/Elf.h
@@ -1,5 +1,4 @@
-#ifndef LINKER_ELF_H
-#define LINKER_ELF_H
+#pragma once
 
 #include "Rts.h"
 #include "LinkerInternals.h"
@@ -13,5 +12,3 @@ int ocRunInit_ELF        ( ObjectCode* oc );
 int ocAllocateSymbolExtras_ELF( ObjectCode *oc );
 
 #include "EndPrivate.h"
-
-#endif /* LINKER_ELF_H */
diff --git a/rts/linker/M32Alloc.h b/rts/linker/M32Alloc.h
index 8ec49cae21..e71f500e08 100644
--- a/rts/linker/M32Alloc.h
+++ b/rts/linker/M32Alloc.h
@@ -6,8 +6,7 @@
  *
  * ---------------------------------------------------------------------------*/
 
-#ifndef RTS_LINKER_M32ALLOC
-#define RTS_LINKER_M32ALLOC
+#pragma once
 
 #if RTS_LINKER_USE_MMAP
 #include <fcntl.h>
@@ -36,5 +35,3 @@ void m32_free(void *addr, size_t size) M32_NO_RETURN;
 void * m32_alloc(size_t size, size_t alignment) M32_NO_RETURN;
 
 #include "EndPrivate.h"
-
-#endif
diff --git a/rts/linker/MachO.h b/rts/linker/MachO.h
index 9362eb7238..c07e2944a1 100644
--- a/rts/linker/MachO.h
+++ b/rts/linker/MachO.h
@@ -1,5 +1,4 @@
-#ifndef LINKER_MACHO_H
-#define LINKER_MACHO_H
+#pragma once
 
 #include "Rts.h"
 
@@ -21,5 +20,3 @@ void machoInitSymbolsWithoutUnderscore( void );
 #endif
 
 #include "EndPrivate.h"
-
-#endif /* LINKER_MACHO_H */
diff --git a/rts/linker/MachOTypes.h b/rts/linker/MachOTypes.h
index 5b2dced81b..b7ee7e2ed7 100644
--- a/rts/linker/MachOTypes.h
+++ b/rts/linker/MachOTypes.h
@@ -1,5 +1,4 @@
-#ifndef MachOTypes_h
-#define MachOTypes_h
+#pragma once
 
 #if defined(OBJFORMAT_MACHO)
 
@@ -130,4 +129,3 @@ typedef struct _SectionFormatInfo {
 } SectionFormatInfo;
 
 #endif /* OBJECTFORMAT_MACHO */
-#endif /* MachOTypes_h */
diff --git a/rts/linker/PEi386.h b/rts/linker/PEi386.h
index 09b8c91c94..b034d6c7c9 100644
--- a/rts/linker/PEi386.h
+++ b/rts/linker/PEi386.h
@@ -1,5 +1,4 @@
-#ifndef LINKER_PE_I386_H
-#define LINKER_PE_I386_H
+#pragma once
 
 #include "Rts.h"
 #include "LinkerInternals.h"
@@ -107,5 +106,3 @@ See #9218
 
 
 #include "EndPrivate.h"
-
-#endif /* LINKER_PE_I386_H */
diff --git a/rts/linker/SymbolExtras.h b/rts/linker/SymbolExtras.h
index 25cb022ab0..d28baf49df 100644
--- a/rts/linker/SymbolExtras.h
+++ b/rts/linker/SymbolExtras.h
@@ -1,5 +1,4 @@
-#ifndef LINKER_SYMBOL_EXTRAS_H
-#define LINKER_SYMBOL_EXTRAS_H
+#pragma once
 
 #include "Rts.h"
 #include "LinkerInternals.h"
@@ -26,5 +25,3 @@ SymbolExtra* makeSymbolExtra( ObjectCode const* oc,
 #endif /* NEED_SYMBOL_EXTRAS */
 
 #include "EndPrivate.h"
-
-#endif /* LINKER_SYMBOL_EXTRAS_H */