[ros-diffs] [sir_richard] 45223: [PERF]: Make all trap handlers, trap exit code, fatal exit code, and exception dispatch code "no return" since it always leads to an iret or other kind of non-directly-returning mechanism. This allows the compiler to optimize better and also remove useless code at the bottom of the functions. Since __builtin_unreachable is only for GCC 4.5, we use exit(0) for now (it will never be reached) to trick GCC.

Author: sir_richard
Date: Sun Jan 24 00:59:59 2010
New Revision: 45223

URL: http://svn.reactos.org/svn/reactos?rev=45223&view=rev
Log:
[PERF]: Make all trap handlers, trap exit code, fatal exit code, and exception dispatch
code "no return" since it always leads to an iret or other kind of
non-directly-returning mechanism. This allows the compiler to optimize better and also
remove useless code at the bottom of the functions. Since __builtin_unreachable is only
for GCC 4.5, we use exit(0) for now (it will never be reached) to trick GCC.

Modified:
    trunk/reactos/ntoskrnl/include/internal/trap_x.h
    trunk/reactos/ntoskrnl/ke/i386/traphdlr.c

Modified: trunk/reactos/ntoskrnl/include/internal/trap_x.h
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/include/internal/…
==============================================================================
--- trunk/reactos/ntoskrnl/include/internal/trap_x.h [iso-8859-1] (original)
+++ trunk/reactos/ntoskrnl/include/internal/trap_x.h [iso-8859-1] Sun Jan 24 00:59:59
2010
@@ -214,6 +214,7 @@
 
 VOID
 FORCEINLINE
+DECLSPEC_NORETURN
 KiDispatchException0Args(IN NTSTATUS Code,
                          IN ULONG_PTR Address,
                          IN PKTRAP_FRAME TrapFrame)
@@ -224,6 +225,7 @@
 
 VOID
 FORCEINLINE
+DECLSPEC_NORETURN
 KiDispatchException1Args(IN NTSTATUS Code,
                          IN ULONG_PTR Address,
                          IN ULONG P1,
@@ -235,6 +237,7 @@
 
 VOID
 FORCEINLINE
+DECLSPEC_NORETURN
 KiDispatchException2Args(IN NTSTATUS Code,
                          IN ULONG_PTR Address,
                          IN ULONG P1,
@@ -247,6 +250,7 @@
 
 FORCEINLINE
 VOID
+DECLSPEC_NORETURN
 KiSystemCallReturn(IN PKTRAP_FRAME TrapFrame)
 {
     /* Restore nonvolatiles, EAX, and do a "jump" back to the kernel caller */
@@ -272,10 +276,12 @@
           [v] "i"(KTRAP_FRAME_ESP)
         : "%esp"
     );
-}
-
-FORCEINLINE
-VOID
+    exit(0);
+}
+
+FORCEINLINE
+VOID
+DECLSPEC_NORETURN
 KiSystemCallTrapReturn(IN PKTRAP_FRAME TrapFrame)
 {
     /* Regular interrupt exit, but we only restore EAX as a volatile */
@@ -299,10 +305,12 @@
           [e] "i"(KTRAP_FRAME_EIP)
         : "%esp"
     );
-}
-
-FORCEINLINE
-VOID
+    exit(0);
+}
+
+FORCEINLINE
+VOID
+DECLSPEC_NORETURN
 KiSystemCallSysExitReturn(IN PKTRAP_FRAME TrapFrame)
 {
     /* Restore nonvolatiles, EAX, and do a SYSEXIT back to the user caller */
@@ -330,10 +338,12 @@
           [v] "i"(KTRAP_FRAME_V86_ES)
         : "%esp"
     );
-}
-
-FORCEINLINE
-VOID
+    exit(0);
+}
+
+FORCEINLINE
+VOID
+DECLSPEC_NORETURN
 KiTrapReturn(IN PKTRAP_FRAME TrapFrame)
 {
     /* Regular interrupt exit */
@@ -361,10 +371,12 @@
           [e] "i"(KTRAP_FRAME_EIP)
         : "%esp"
     );
-}
-
-FORCEINLINE
-VOID
+    exit(0);
+}
+
+FORCEINLINE
+VOID
+DECLSPEC_NORETURN
 KiEditedTrapReturn(IN PKTRAP_FRAME TrapFrame)
 {
     /* Regular interrupt exit */
@@ -393,6 +405,7 @@
           [e] "i"(KTRAP_FRAME_ERROR_CODE) /* We *WANT* the error code since ESP
is there! */
         : "%esp"
     );
+    exit(0);
 }
 
 NTSTATUS

Modified: trunk/reactos/ntoskrnl/ke/i386/traphdlr.c
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/ke/i386/traphdlr.…
==============================================================================
--- trunk/reactos/ntoskrnl/ke/i386/traphdlr.c [iso-8859-1] (original)
+++ trunk/reactos/ntoskrnl/ke/i386/traphdlr.c [iso-8859-1] Sun Jan 24 00:59:59 2010
@@ -50,6 +50,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiExitTrap(IN PKTRAP_FRAME TrapFrame,
            IN UCHAR Skip)
 {
@@ -235,6 +236,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiEoiHelper(IN PKTRAP_FRAME TrapFrame)
 {
     /* Disable interrupts until we return */
@@ -249,6 +251,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiServiceExit(IN PKTRAP_FRAME TrapFrame,
               IN NTSTATUS Status)
 {
@@ -267,6 +270,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiServiceExit2(IN PKTRAP_FRAME TrapFrame)
 {
     /* Disable interrupts until we return */
@@ -423,6 +427,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiSystemFatalException(IN ULONG ExceptionCode,
                        IN PKTRAP_FRAME TrapFrame)
 {
@@ -437,6 +442,7 @@
 
 VOID
 NTAPI
+DECLSPEC_NORETURN
 KiDispatchExceptionFromTrapFrame(IN NTSTATUS Code,
                                  IN ULONG_PTR Address,
                                  IN ULONG ParameterCount,
@@ -477,6 +483,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiDebugHandler(IN PKTRAP_FRAME TrapFrame,
                IN ULONG Parameter1,
                IN ULONG Parameter2,
@@ -500,6 +507,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiNpxHandler(IN PKTRAP_FRAME TrapFrame,
              IN PKTHREAD Thread,
              IN PFX_SAVE_AREA SaveArea)
@@ -656,6 +664,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiTrap00Handler(IN PKTRAP_FRAME TrapFrame)
 {
     /* Save trap frame */
@@ -675,6 +684,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiTrap01Handler(IN PKTRAP_FRAME TrapFrame)
 {
     /* Save trap frame */
@@ -694,6 +704,7 @@
 }
 
 VOID
+DECLSPEC_NORETURN
 KiTrap02(VOID)
 {
     PKTSS Tss, NmiTss;
@@ -840,6 +851,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiTrap03Handler(IN PKTRAP_FRAME TrapFrame)
 {
     /* Save trap frame */
@@ -851,6 +863,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiTrap04Handler(IN PKTRAP_FRAME TrapFrame)
 {
     /* Save trap frame */
@@ -870,6 +883,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiTrap05Handler(IN PKTRAP_FRAME TrapFrame)
 {
     /* Save trap frame */
@@ -892,6 +906,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiTrap06Handler(IN PKTRAP_FRAME TrapFrame)
 {
     PUCHAR Instruction;
@@ -937,6 +952,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiTrap07Handler(IN PKTRAP_FRAME TrapFrame)
 {
     PKTHREAD Thread, NpxThread;
@@ -1046,6 +1062,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiTrap08Handler(IN PKTRAP_FRAME TrapFrame)
 {
     /* FIXME: Not handled */
@@ -1054,6 +1071,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiTrap09Handler(IN PKTRAP_FRAME TrapFrame)
 {
     /* Save trap frame */
@@ -1066,6 +1084,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiTrap0AHandler(IN PKTRAP_FRAME TrapFrame)
 {
     /* Save trap frame */
@@ -1080,6 +1099,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiTrap0BHandler(IN PKTRAP_FRAME TrapFrame)
 {
     /* Save trap frame */
@@ -1092,6 +1112,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiTrap0CHandler(IN PKTRAP_FRAME TrapFrame)
 {
     /* Save trap frame */
@@ -1104,6 +1125,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiTrap0DHandler(IN PKTRAP_FRAME TrapFrame,
                 IN ULONG EFlags)
 {
@@ -1388,6 +1410,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiTrap0EHandler(IN PKTRAP_FRAME TrapFrame)
 {
     PKTHREAD Thread;
@@ -1510,6 +1533,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiTrap0FHandler(IN PKTRAP_FRAME TrapFrame)
 {
     /* Save trap frame */
@@ -1520,9 +1544,9 @@
     KiSystemFatalException(EXCEPTION_RESERVED_TRAP, TrapFrame);
 }
 
-
-VOID
-FASTCALL
+VOID
+FASTCALL
+DECLSPEC_NORETURN
 KiTrap10Handler(IN PKTRAP_FRAME TrapFrame)
 {
     PKTHREAD Thread;
@@ -1550,6 +1574,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiTrap11Handler(IN PKTRAP_FRAME TrapFrame)
 {
     /* Save trap frame */
@@ -1562,6 +1587,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiTrap13Handler(IN PKTRAP_FRAME TrapFrame)
 {
     PKTHREAD Thread;
@@ -1664,6 +1690,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiRaiseAssertionHandler(IN PKTRAP_FRAME TrapFrame)
 {
     /* Save trap frame */
@@ -1680,6 +1707,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiDebugServiceHandler(IN PKTRAP_FRAME TrapFrame)
 {
     /* Save trap frame */
@@ -1694,6 +1722,7 @@
 
 VOID
 FASTCALL
+DECLSPEC_NORETURN
 KiSystemCall(IN ULONG SystemCallNumber,
              IN PVOID Arguments)
 {
@@ -1784,6 +1813,7 @@
 
 VOID
 FORCEINLINE
+DECLSPEC_NORETURN
 KiSystemCallHandler(IN PKTRAP_FRAME TrapFrame,
                     IN ULONG ServiceNumber,
                     IN PVOID Arguments,
@@ -1825,6 +1855,7 @@
 
 VOID
 __attribute__((regparm(3)))
+DECLSPEC_NORETURN
 KiFastCallEntryHandler(IN ULONG ServiceNumber,
                        IN PVOID Arguments,
                        IN PKTRAP_FRAME TrapFrame)
@@ -1858,6 +1889,7 @@
 
 VOID
 __attribute__((regparm(3)))
+DECLSPEC_NORETURN
 KiSystemServiceHandler(IN ULONG ServiceNumber,
                        IN PVOID Arguments,
                        IN PKTRAP_FRAME TrapFrame)