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

10 files changed, 10 insertions, 41 deletions

diff --git a/includes/stg/DLL.h b/includes/stg/DLL.h
index 8ab5d8c3d4..cf857a8682 100644
--- a/includes/stg/DLL.h
+++ b/includes/stg/DLL.h
@@ -11,8 +11,7 @@
  *
  * ---------------------------------------------------------------------------*/
 
-#ifndef __STGDLL_H__
-#define __STGDLL_H__ 1
+#pragma once
 
 #if defined(COMPILING_WINDOWS_DLL)
 #  if defined(x86_64_HOST_ARCH)
@@ -71,5 +70,3 @@
 #else
 #define DLL_IMPORT_STDLIB DLLIMPORT
 #endif
-
-#endif /* __STGDLL_H__ */
diff --git a/includes/stg/HaskellMachRegs.h b/includes/stg/HaskellMachRegs.h
index e95cefd822..37e687bc4e 100644
--- a/includes/stg/HaskellMachRegs.h
+++ b/includes/stg/HaskellMachRegs.h
@@ -12,8 +12,7 @@
  *
  * ---------------------------------------------------------------------------*/
 
-#ifndef HASKELLMACHREGS_H
-#define HASKELLMACHREGS_H
+#pragma once
 
 /*
  * Defining NO_REGS causes no global registers to be used.  NO_REGS is
@@ -45,5 +44,3 @@
 #endif
 
 #include "MachRegs.h"
-
-#endif /* HASKELLMACHREGS_H */
diff --git a/includes/stg/MachRegs.h b/includes/stg/MachRegs.h
index 232ce03810..a0cf595505 100644
--- a/includes/stg/MachRegs.h
+++ b/includes/stg/MachRegs.h
@@ -12,8 +12,7 @@
  *
  * ---------------------------------------------------------------------------*/
 
-#ifndef MACHREGS_H
-#define MACHREGS_H
+#pragma once
 
 /* This file is #included into Haskell code in the compiler: #defines
  * only in here please.
@@ -714,5 +713,3 @@ the stack. See Note [Overlapping global registers] for implications.
 #else
 #undef NO_ARG_REGS
 #endif
-
-#endif /* MACHREGS_H */
diff --git a/includes/stg/MiscClosures.h b/includes/stg/MiscClosures.h
index 9d907ab3ba..1181abcca4 100644
--- a/includes/stg/MiscClosures.h
+++ b/includes/stg/MiscClosures.h
@@ -17,8 +17,7 @@
  *
  * --------------------------------------------------------------------------*/
 
-#ifndef STGMISCCLOSURES_H
-#define STGMISCCLOSURES_H
+#pragma once
 
 #if IN_STG_CODE
 #  define RTS_RET_INFO(i)   extern W_(i)[]
@@ -532,5 +531,3 @@ void * pushCostCentre (void *ccs, void *cc);
 extern unsigned int n_capabilities;
 
 #endif
-
-#endif /* STGMISCCLOSURES_H */
diff --git a/includes/stg/Prim.h b/includes/stg/Prim.h
index 9872512701..fa3a3ec91f 100644
--- a/includes/stg/Prim.h
+++ b/includes/stg/Prim.h
@@ -11,8 +11,7 @@
  *
  * -------------------------------------------------------------------------- */
 
-#ifndef PRIM_H
-#define PRIM_H
+#pragma once
 
 /* libraries/ghc-prim/cbits/atomic.c */
 StgWord hs_atomic_add8(StgWord x, StgWord val);
@@ -81,5 +80,3 @@ StgWord hs_ctz8(StgWord x);
 StgWord hs_ctz16(StgWord x);
 StgWord hs_ctz32(StgWord x);
 StgWord hs_ctz64(StgWord64 x);
-
-#endif /* PRIM_H */
diff --git a/includes/stg/Regs.h b/includes/stg/Regs.h
index 36324632d2..cf9e306504 100644
--- a/includes/stg/Regs.h
+++ b/includes/stg/Regs.h
@@ -11,8 +11,7 @@
  *
  * ---------------------------------------------------------------------------*/
 
-#ifndef REGS_H
-#define REGS_H
+#pragma once
 
 /*
  * The STG machine has a collection of "registers", each one of which
@@ -527,5 +526,3 @@ GLOBAL_REG_DECL(bdescr *,HpAlloc,REG_HpAlloc)
 #define stg_gc_fun                (FunReg->stgGCFun)
 
 #endif /* IN_STG_CODE */
-
-#endif /* REGS_H */
diff --git a/includes/stg/RtsMachRegs.h b/includes/stg/RtsMachRegs.h
index 29262dc17a..5a0464b909 100644
--- a/includes/stg/RtsMachRegs.h
+++ b/includes/stg/RtsMachRegs.h
@@ -12,8 +12,7 @@
  *
  * ---------------------------------------------------------------------------*/
 
-#ifndef RTSMACHREGS_H
-#define RTSMACHREGS_H
+#pragma once
 
 #ifdef UnregisterisedCompiler
 #ifndef NO_REGS
@@ -51,5 +50,3 @@
 #endif
 
 #include "MachRegs.h"
-
-#endif /* RTSMACHREGS_H */
diff --git a/includes/stg/SMP.h b/includes/stg/SMP.h
index 0e806b6716..e4ae6121fa 100644
--- a/includes/stg/SMP.h
+++ b/includes/stg/SMP.h
@@ -11,8 +11,7 @@
  *
  * -------------------------------------------------------------------------- */
 
-#ifndef SMP_H
-#define SMP_H
+#pragma once
 
 #if arm_HOST_ARCH && defined(arm_HOST_ARCH_PRE_ARMv6)
 void arm_atomic_spin_lock(void);
@@ -299,5 +298,3 @@ atomic_dec(StgVolatilePtr p)
 #define VOLATILE_LOAD(p) ((StgWord)*((StgWord*)(p)))
 
 #endif /* !THREADED_RTS */
-
-#endif /* SMP_H */
diff --git a/includes/stg/Ticky.h b/includes/stg/Ticky.h
index 5143c2fd5c..1e16a1ae08 100644
--- a/includes/stg/Ticky.h
+++ b/includes/stg/Ticky.h
@@ -11,8 +11,7 @@
  *
  * -------------------------------------------------------------------------- */
 
-#ifndef TICKYCOUNTERS_H
-#define TICKYCOUNTERS_H
+#pragma once
 
 /* These should probably be automatically generated in order to
    keep them consistent with the macros that use them (which are
@@ -215,6 +214,3 @@ EXTERN StgInt RET_UNBOXED_TUP_hst[TICKY_BIN_COUNT] INIT({0});
 #define TICK_ALLOC_SE_THK(g,s)
 
 #endif
-
-
-#endif /* TICKYCOUNTERS_H */
diff --git a/includes/stg/Types.h b/includes/stg/Types.h
index 3a08eb2f85..af6a51791c 100644
--- a/includes/stg/Types.h
+++ b/includes/stg/Types.h
@@ -18,8 +18,7 @@
  *
  * ---------------------------------------------------------------------------*/
 
-#ifndef STGTYPES_H
-#define STGTYPES_H
+#pragma once
 
 #if defined(mingw32_HOST_OS)
 /* Inform mingw we want the ISO rather than Windows printf format specifiers. */
@@ -182,5 +181,3 @@ typedef StgWord8*          StgByteArray;
 
 typedef void  *(*(*StgFunPtr)(void))(void);
 typedef StgFunPtr StgFun(void);
-
-#endif /* STGTYPES_H */