This patch implements the new gdbarch method gdbarch_gdb_signal_to_target.

It will be used when one wants to convert between the internal GDB signal
representation (enum gdb_signal) and the target's representation.

The idea of this patch came from a chat between Pedro and I on IRC, plus
the discussion of my patches to add the new $_exitsignal convenience
variable:

	<http://sourceware.org/ml/gdb-patches/2013-06/msg00452.html>
	<http://sourceware.org/ml/gdb-patches/2013-06/msg00352.html>

What I did was to investigate, on the Linux kernel, which targets shared
the signal numbers definition with the generic definition, present at
<include/uapi/asm-generic/signal.h>.  For the record, I used linux-3.10-rc7
as the main source of information, always looking at
<arch/<ARCH_NAME>/include/uapi/asm/signal.h>.  For SIGRTMAX (which defaults
to _NSIG in most cases), I had to look at different signal-related
files, but most of them (except MIPS) were defined to 64 anyway.

Then, with all the differences in hand, I implemented the bits on each
target.

2013-08-09  Sergio Durigan Junior  <sergiodj@redhat.com>

	* linux-tdep.c: Define enum with generic signal numbers.
	(linux_gdb_signal_from_target): New function.
	(linux_gdb_signal_to_target): Likewise.
	(linux_init_abi): Set gdbarch_gdb_signal_{to,from}_target
	methods to the functions above.
	* linux-tdep.h (linux_gdb_signal_from_target): New prototype.
	(linux_gdb_signal_to_target): Likewise.
	* alpha-linux-tdep.c: Define new enum with signals different
	from generic Linux kernel.
	(alpha_linux_gdb_signal_from_target): New function.
	(alpha_linux_gdb_signal_to_target): Likewise.
	(alpha_linux_init_abi): Set gdbarch_gdb_signal_{to,from}_target
	with the functions mentioned above.
	* avr-tdep.c: Define enum with differences between Linux kernel
	and AVR signals.
	(avr_linux_gdb_signal_from_target): New function.
	(avr_linux_gdb_signal_to_target): Likewise.
	(avr_gdbarch_init): Set gdbarch_gdb_signal_{to,from}_target to
	the functions mentioned above.
	* sparc-linux-tdep.c: Define enum with differences between SPARC
	and generic Linux kernel signal numbers.
	(sparc32_linux_gdb_signal_from_target): New function.
	(sparc32_linux_gdb_signal_to_target): Likewise.
	(sparc32_linux_init_abi): Set gdbarch_gdb_signal_{to,from}_target
	to the functions defined above.
	* xtensa-linux-tdep.c: Define enum with differences between
	Xtensa and Linux kernel generic signals.
	(xtensa_linux_gdb_signal_from_target): New function.
	(xtensa_linux_gdb_signal_to_target): Likewise.
	(xtensa_linux_init_abi): Set gdbarch_gdb_signal_to_target
	to the functions defined above.
	* mips-linux-tdep.c: Define enum with differences between
	signals in MIPS and Linux kernel generic ones.
	(mips_gdb_signal_to_target): New function.
	(mips_gdb_signal_from_target): Redefine to use new enum, handle
	only different signals from the Linux kernel generic.
	(mips_linux_init_abi): Set gdbarch_gdb_signal_{to,from}_target
	the functions defined above.
	* mips-linux-tdep.h (enum mips_signals): Remove.

1 files changed, 185 insertions, 56 deletions

diff --git a/gdb/mips-linux-tdep.c b/gdb/mips-linux-tdep.c
index 484b39f..8d17839 100644
--- a/gdb/mips-linux-tdep.c
+++ b/gdb/mips-linux-tdep.c
@@ -45,6 +45,42 @@
 
 static struct target_so_ops mips_svr4_so_ops;
 
+/* This enum represents the signals' numbers on the MIPS
+   architecture.  It just contains the signal definitions which are
+   different from the generic implementation.
+
+   It is derived from the file <arch/mips/include/uapi/asm/signal.h>,
+   from the Linux kernel tree.  */
+
+enum
+  {
+    MIPS_LINUX_SIGEMT = 7,
+    MIPS_LINUX_SIGBUS = 10,
+    MIPS_LINUX_SIGSYS = 12,
+    MIPS_LINUX_SIGUSR1 = 16,
+    MIPS_LINUX_SIGUSR2 = 17,
+    MIPS_LINUX_SIGCHLD = 18,
+    MIPS_LINUX_SIGCLD = MIPS_LINUX_SIGCHLD,
+    MIPS_LINUX_SIGPWR = 19,
+    MIPS_LINUX_SIGWINCH = 20,
+    MIPS_LINUX_SIGURG = 21,
+    MIPS_LINUX_SIGIO = 22,
+    MIPS_LINUX_SIGPOLL = MIPS_LINUX_SIGIO,
+    MIPS_LINUX_SIGSTOP = 23,
+    MIPS_LINUX_SIGTSTP = 24,
+    MIPS_LINUX_SIGCONT = 25,
+    MIPS_LINUX_SIGTTIN = 26,
+    MIPS_LINUX_SIGTTOU = 27,
+    MIPS_LINUX_SIGVTALRM = 28,
+    MIPS_LINUX_SIGPROF = 29,
+    MIPS_LINUX_SIGXCPU = 30,
+    MIPS_LINUX_SIGXFSZ = 31,
+
+    MIPS_LINUX_SIGRTMIN = 32,
+    MIPS_LINUX_SIGRT64 = 64,
+    MIPS_LINUX_SIGRTMAX = 127,
+  };
+
 /* Figure out where the longjmp will land.
    We expect the first arg to be a pointer to the jmp_buf structure
    from which we extract the pc (MIPS_LINUX_JB_PC) that we will land
@@ -1339,94 +1375,184 @@ mips_linux_get_syscall_number (struct gdbarch *gdbarch,
   return ret;
 }
 
+/* Implementation of `gdbarch_gdb_signal_to_target', as defined in
+   gdbarch.h.  */
+
+static int
+mips_gdb_signal_to_target (struct gdbarch *gdbarch,
+			   enum gdb_signal signal)
+{
+  switch (signal)
+    {
+    case GDB_SIGNAL_EMT:
+      return MIPS_LINUX_SIGEMT;
+
+    case GDB_SIGNAL_BUS:
+      return MIPS_LINUX_SIGBUS;
+
+    case GDB_SIGNAL_SYS:
+      return MIPS_LINUX_SIGSYS;
+
+    case GDB_SIGNAL_USR1:
+      return MIPS_LINUX_SIGUSR1;
+
+    case GDB_SIGNAL_USR2:
+      return MIPS_LINUX_SIGUSR2;
+
+    case GDB_SIGNAL_CHLD:
+      return MIPS_LINUX_SIGCHLD;
+
+    case GDB_SIGNAL_PWR:
+      return MIPS_LINUX_SIGPWR;
+
+    case GDB_SIGNAL_WINCH:
+      return MIPS_LINUX_SIGWINCH;
+
+    case GDB_SIGNAL_URG:
+      return MIPS_LINUX_SIGURG;
+
+    case GDB_SIGNAL_IO:
+      return MIPS_LINUX_SIGIO;
+
+    case GDB_SIGNAL_POLL:
+      return MIPS_LINUX_SIGPOLL;
+
+    case GDB_SIGNAL_STOP:
+      return MIPS_LINUX_SIGSTOP;
+
+    case GDB_SIGNAL_TSTP:
+      return MIPS_LINUX_SIGTSTP;
+
+    case GDB_SIGNAL_CONT:
+      return MIPS_LINUX_SIGCONT;
+
+    case GDB_SIGNAL_TTIN:
+      return MIPS_LINUX_SIGTTIN;
+
+    case GDB_SIGNAL_TTOU:
+      return MIPS_LINUX_SIGTTOU;
+
+    case GDB_SIGNAL_VTALRM:
+      return MIPS_LINUX_SIGVTALRM;
+
+    case GDB_SIGNAL_PROF:
+      return MIPS_LINUX_SIGPROF;
+
+    case GDB_SIGNAL_XCPU:
+      return MIPS_LINUX_SIGXCPU;
+
+    case GDB_SIGNAL_XFSZ:
+      return MIPS_LINUX_SIGXFSZ;
+
+    /* GDB_SIGNAL_REALTIME_32 is not continuous in <gdb/signals.def>,
+       therefore we have to handle it here.  */
+    case GDB_SIGNAL_REALTIME_32:
+      return MIPS_LINUX_SIGRTMIN;
+    }
+
+  if (signal >= GDB_SIGNAL_REALTIME_33
+      && signal <= GDB_SIGNAL_REALTIME_63)
+    {
+      int offset = signal - GDB_SIGNAL_REALTIME_33;
+
+      return MIPS_LINUX_SIGRTMIN + 1 + offset;
+    }
+  else if (signal >= GDB_SIGNAL_REALTIME_64
+	   && signal <= GDB_SIGNAL_REALTIME_127)
+    {
+      int offset = signal - GDB_SIGNAL_REALTIME_64;
+
+      return MIPS_LINUX_SIGRT64 + offset;
+    }
+
+  return linux_gdb_signal_to_target (gdbarch, signal);
+}
+
 /* Translate signals based on MIPS signal values.
    Adapted from gdb/common/signals.c.  */
 
 static enum gdb_signal
-mips_gdb_signal_from_target (struct gdbarch *gdbarch, int signo)
+mips_gdb_signal_from_target (struct gdbarch *gdbarch, int signal)
 {
-  switch (signo)
+  switch (signal)
     {
-    case 0:
-      return GDB_SIGNAL_0;
-    case MIPS_SIGHUP:
-      return GDB_SIGNAL_HUP;
-    case MIPS_SIGINT:
-      return GDB_SIGNAL_INT;
-    case MIPS_SIGQUIT:
-      return GDB_SIGNAL_QUIT;
-    case MIPS_SIGILL:
-      return GDB_SIGNAL_ILL;
-    case MIPS_SIGTRAP:
-      return GDB_SIGNAL_TRAP;
-    case MIPS_SIGABRT:
-      return GDB_SIGNAL_ABRT;
-    case MIPS_SIGEMT:
+    case MIPS_LINUX_SIGEMT:
       return GDB_SIGNAL_EMT;
-    case MIPS_SIGFPE:
-      return GDB_SIGNAL_FPE;
-    case MIPS_SIGKILL:
-      return GDB_SIGNAL_KILL;
-    case MIPS_SIGBUS:
+
+    case MIPS_LINUX_SIGBUS:
       return GDB_SIGNAL_BUS;
-    case MIPS_SIGSEGV:
-      return GDB_SIGNAL_SEGV;
-    case MIPS_SIGSYS:
+
+    case MIPS_LINUX_SIGSYS:
       return GDB_SIGNAL_SYS;
-    case MIPS_SIGPIPE:
-      return GDB_SIGNAL_PIPE;
-    case MIPS_SIGALRM:
-      return GDB_SIGNAL_ALRM;
-    case MIPS_SIGTERM:
-      return GDB_SIGNAL_TERM;
-    case MIPS_SIGUSR1:
+
+    case MIPS_LINUX_SIGUSR1:
       return GDB_SIGNAL_USR1;
-    case MIPS_SIGUSR2:
+
+    case MIPS_LINUX_SIGUSR2:
       return GDB_SIGNAL_USR2;
-    case MIPS_SIGCHLD:
+
+    case MIPS_LINUX_SIGCHLD:
       return GDB_SIGNAL_CHLD;
-    case MIPS_SIGPWR:
+
+    case MIPS_LINUX_SIGPWR:
       return GDB_SIGNAL_PWR;
-    case MIPS_SIGWINCH:
+
+    case MIPS_LINUX_SIGWINCH:
       return GDB_SIGNAL_WINCH;
-    case MIPS_SIGURG:
+
+    case MIPS_LINUX_SIGURG:
       return GDB_SIGNAL_URG;
-    case MIPS_SIGPOLL:
-      return GDB_SIGNAL_POLL;
-    case MIPS_SIGSTOP:
+
+    /* No way to differentiate between SIGIO and SIGPOLL.
+       Therefore, we just handle the first one.  */
+    case MIPS_LINUX_SIGIO:
+      return GDB_SIGNAL_IO;
+
+    case MIPS_LINUX_SIGSTOP:
       return GDB_SIGNAL_STOP;
-    case MIPS_SIGTSTP:
+
+    case MIPS_LINUX_SIGTSTP:
       return GDB_SIGNAL_TSTP;
-    case MIPS_SIGCONT:
+
+    case MIPS_LINUX_SIGCONT:
       return GDB_SIGNAL_CONT;
-    case MIPS_SIGTTIN:
+
+    case MIPS_LINUX_SIGTTIN:
       return GDB_SIGNAL_TTIN;
-    case MIPS_SIGTTOU:
+
+    case MIPS_LINUX_SIGTTOU:
       return GDB_SIGNAL_TTOU;
-    case MIPS_SIGVTALRM:
+
+    case MIPS_LINUX_SIGVTALRM:
       return GDB_SIGNAL_VTALRM;
-    case MIPS_SIGPROF:
+
+    case MIPS_LINUX_SIGPROF:
       return GDB_SIGNAL_PROF;
-    case MIPS_SIGXCPU:
+
+    case MIPS_LINUX_SIGXCPU:
       return GDB_SIGNAL_XCPU;
-    case MIPS_SIGXFSZ:
+
+    case MIPS_LINUX_SIGXFSZ:
       return GDB_SIGNAL_XFSZ;
-  }
+    }
 
-  if (signo >= MIPS_SIGRTMIN && signo <= MIPS_SIGRTMAX)
+  if (signal >= MIPS_LINUX_SIGRTMIN && signal <= MIPS_LINUX_SIGRTMAX)
     {
       /* GDB_SIGNAL_REALTIME values are not contiguous, map parts of
          the MIPS block to the respective GDB_SIGNAL_REALTIME blocks.  */
-      signo -= MIPS_SIGRTMIN;
-      if (signo == 0)
+      int offset = signal - MIPS_LINUX_SIGRTMIN;
+
+      if (offset == 0)
 	return GDB_SIGNAL_REALTIME_32;
-      else if (signo < 32)
-	return ((enum gdb_signal) (signo - 1 + (int) GDB_SIGNAL_REALTIME_33));
+      else if (offset < 32)
+	return (enum gdb_signal) (offset - 1
+				  + (int) GDB_SIGNAL_REALTIME_33);
       else
-	return ((enum gdb_signal) (signo - 32 + (int) GDB_SIGNAL_REALTIME_64));
+	return (enum gdb_signal) (offset - 32
+				  + (int) GDB_SIGNAL_REALTIME_64);
     }
 
-  return GDB_SIGNAL_UNKNOWN;
+  return linux_gdb_signal_from_target (gdbarch, signal);
 }
 
 /* Initialize one of the GNU/Linux OS ABIs.  */
@@ -1516,6 +1642,9 @@ mips_linux_init_abi (struct gdbarch_info info,
   set_gdbarch_gdb_signal_from_target (gdbarch,
 				      mips_gdb_signal_from_target);
 
+  set_gdbarch_gdb_signal_to_target (gdbarch,
+				    mips_gdb_signal_to_target);
+
   tdep->syscall_next_pc = mips_linux_syscall_next_pc;
 
   if (tdesc_data)