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, 74 insertions, 0 deletions

diff --git a/gdb/xtensa-linux-tdep.c b/gdb/xtensa-linux-tdep.c
index b7f11b97741..e7c62875710 100644
--- a/gdb/xtensa-linux-tdep.c
+++ b/gdb/xtensa-linux-tdep.c
@@ -23,6 +23,75 @@
 #include "solib-svr4.h"
 #include "symtab.h"
 
+/* This enum represents the signals' numbers on the Xtensa
+   architecture.  It just contains the signal definitions which are
+   different from the generic implementation.
+
+   It is derived from the file <arch/xtensa/include/uapi/asm/signal.h>,
+   from the Linux kernel tree.  */
+
+enum
+  {
+    XTENSA_LINUX_SIGRTMIN = 32,
+    XTENSA_LINUX_SIGRTMAX = 63,
+  };
+
+/* Implementation of `gdbarch_gdb_signal_from_target', as defined in
+   gdbarch.h.  */
+
+static enum gdb_signal
+xtensa_linux_gdb_signal_from_target (struct gdbarch *gdbarch,
+				   int signal)
+{
+  if (signal >= XTENSA_LINUX_SIGRTMIN && signal <= XTENSA_LINUX_SIGRTMAX)
+    {
+      int offset = signal - XTENSA_LINUX_SIGRTMIN;
+
+      if (offset == 0)
+	return GDB_SIGNAL_REALTIME_32;
+      else
+	return (enum gdb_signal) (offset - 1
+				  + (int) GDB_SIGNAL_REALTIME_33);
+    }
+  else if (signal > XTENSA_LINUX_SIGRTMAX)
+    return GDB_SIGNAL_UNKNOWN;
+
+  return linux_gdb_signal_from_target (gdbarch, signal);
+}
+
+/* Implementation of `gdbarch_gdb_signal_to_target', as defined in
+   gdbarch.h.  */
+
+static int
+xtensa_linux_gdb_signal_to_target (struct gdbarch *gdbarch,
+				   enum gdb_signal signal)
+{
+  switch (signal)
+    {
+    /* GDB_SIGNAL_REALTIME_32 is not continuous in <gdb/signals.def>,
+       therefore we have to handle it here.  */
+    case GDB_SIGNAL_REALTIME_32:
+      return XTENSA_LINUX_SIGRTMIN;
+
+    /* GDB_SIGNAL_REALTIME_64 is not valid on Xtensa.  */
+    case GDB_SIGNAL_REALTIME_64:
+      return -1;
+    }
+
+  /* GDB_SIGNAL_REALTIME_33 to _63 are continuous.
+
+     Xtensa does not have _64.  */
+  if (signal >= GDB_SIGNAL_REALTIME_33
+      && signal <= GDB_SIGNAL_REALTIME_63)
+    {
+      int offset = signal - GDB_SIGNAL_REALTIME_33;
+
+      return XTENSA_LINUX_SIGRTMIN + 1 + offset;
+    }
+
+  return linux_gdb_signal_to_target (gdbarch, signal);
+}
+
 /* OS specific initialization of gdbarch.  */
 
 static void
@@ -32,6 +101,11 @@ xtensa_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 
   set_solib_svr4_fetch_link_map_offsets
     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
+
+  set_gdbarch_gdb_signal_from_target (gdbarch,
+				      xtensa_linux_gdb_signal_from_target);
+  set_gdbarch_gdb_signal_to_target (gdbarch,
+				    xtensa_linux_gdb_signal_to_target);
 }
 
 /* Provide a prototype to silence -Wmissing-prototypes.  */