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[commit] Signal unwinder for mips-irix N32


This change adds a signal unwinder for mips-irix N32.  As explained
in the code, this change has only been tested on N32, but should be
fairly easily adaptable for N64.  Perhaps the insn description of
the sigtramp routine might be different, but there should otherwise
be little difference besides a few offsets.
 
gdb/ChangeLog:

        Signal unwinder for mips-irix N32.
        * mips-irix-tdep.c: #include mips-tdep.h, trad-frame.h, and
        tramp-frame.h.
        (SIGTRAMP_FRAME_SIZE, SIGCONTEXT_PC_OFF, SIGCONTEXT_REGS_OFF)
        (SIGCONTEXT_FPREGS_OFF, SIGCONTEXT_FPCSR_OFF, SIGCONTEXT_HI_OFF)
        (SIGCONTEXT_LO_OFF): New macros.
        (mips_irix_n32_tramp_frame_init): New function.
        (mips_irix_n32_tramp_frame): New static constant.
        (mips_irix_init_abi): Prepend the mips_irix_n32_tramp_frame unwinder.

-- 
Joel
gdb/ChangeLog:

        Signal unwinder for mips-irix N32.
        * mips-irix-tdep.c: #include mips-tdep.h, trad-frame.h, and
        tramp-frame.h.
        (SIGTRAMP_FRAME_SIZE, SIGCONTEXT_PC_OFF, SIGCONTEXT_REGS_OFF)
        (SIGCONTEXT_FPREGS_OFF, SIGCONTEXT_FPCSR_OFF, SIGCONTEXT_HI_OFF)
        (SIGCONTEXT_LO_OFF): New macros.
        (mips_irix_n32_tramp_frame_init): New function.
        (mips_irix_n32_tramp_frame): New static constant.
        (mips_irix_init_abi): Prepend the mips_irix_n32_tramp_frame unwinder.
---
 gdb/mips-irix-tdep.c |  153 +++++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 152 insertions(+), 1 deletions(-)

diff --git a/gdb/mips-irix-tdep.c b/gdb/mips-irix-tdep.c
index 92d1489..1965964 100644
--- a/gdb/mips-irix-tdep.c
+++ b/gdb/mips-irix-tdep.c
@@ -23,8 +23,10 @@
 #include "gdb_string.h"
 #include "solib.h"
 #include "solib-irix.h"
-
 #include "elf-bfd.h"
+#include "mips-tdep.h"
+#include "trad-frame.h"
+#include "tramp-frame.h"
 
 static void
 mips_irix_elf_osabi_sniff_abi_tag_sections (bfd *abfd, asection *sect,
@@ -77,11 +79,160 @@ mips_irix_elf_osabi_sniffer (bfd *abfd)
   return osabi;
 }
 
+/* Unwinding past the signal handler on mips-irix.
+
+   Note: The following has only been tested with N32, but can probably
+         be made to work with a small number of adjustments.
+
+   On mips-irix, the sigcontext_t structure is stored at the base
+   of the frame established by the _sigtramp function.  The definition
+   of this structure can be found in <sys/signal.h> (comments have been
+   C++'ified to avoid a collision with the C-style comment delimiters
+   used by this comment):
+
+      typedef struct sigcontext {
+        __uint32_t      sc_regmask;     // regs to restore in sigcleanup
+        __uint32_t      sc_status;      // cp0 status register
+        __uint64_t      sc_pc;          // pc at time of signal
+        // General purpose registers
+        __uint64_t      sc_regs[32];    // processor regs 0 to 31
+        // Floating point coprocessor state
+        __uint64_t      sc_fpregs[32];  // fp regs 0 to 31
+        __uint32_t      sc_ownedfp;     // fp has been used
+        __uint32_t      sc_fpc_csr;     // fpu control and status reg
+        __uint32_t      sc_fpc_eir;     // fpu exception instruction reg
+                                        // implementation/revision
+        __uint32_t      sc_ssflags;     // signal stack state to restore
+        __uint64_t      sc_mdhi;        // Multiplier hi and low regs
+        __uint64_t      sc_mdlo;
+        // System coprocessor registers at time of signal
+        __uint64_t      sc_cause;       // cp0 cause register
+        __uint64_t      sc_badvaddr;    // cp0 bad virtual address
+        __uint64_t      sc_triggersave; // state of graphics trigger (SGI)
+        sigset_t        sc_sigset;      // signal mask to restore
+        __uint64_t      sc_fp_rounded_result;   // for Ieee 754 support
+        __uint64_t      sc_pad[31];
+      } sigcontext_t;
+
+   The following macros provide the offset of some of the fields
+   used to retrieve the value of the registers before the signal
+   was raised.  */
+
+/* The size of the sigtramp frame.  The sigtramp frame base can then
+   be computed by adding this size to the SP.  */
+#define SIGTRAMP_FRAME_SIZE 48
+/* The offset in sigcontext_t where the PC is saved.  */
+#define SIGCONTEXT_PC_OFF 8
+/* The offset in sigcontext_t where the GP registers are saved.  */
+#define SIGCONTEXT_REGS_OFF (SIGCONTEXT_PC_OFF + 8)
+/* The offset in sigcontext_t where the FP regsiters are saved.  */
+#define SIGCONTEXT_FPREGS_OFF (SIGCONTEXT_REGS_OFF + 32 * 8)
+/* The offset in sigcontext_t where the FP CSR register is saved.  */
+#define SIGCONTEXT_FPCSR_OFF (SIGCONTEXT_FPREGS_OFF + 32 * 8 + 4)
+/* The offset in sigcontext_t where the multiplier hi register is saved.  */
+#define SIGCONTEXT_HI_OFF (SIGCONTEXT_FPCSR_OFF + 2 * 4)
+/* The offset in sigcontext_t where the multiplier lo register is saved.  */
+#define SIGCONTEXT_LO_OFF (SIGCONTEXT_HI_OFF + 4)
+
+/* Implement the "init" routine in struct tramp_frame for the N32 ABI
+   on mips-irix.  */
+static void
+mips_irix_n32_tramp_frame_init (const struct tramp_frame *self,
+				struct frame_info *this_frame,
+				struct trad_frame_cache *this_cache,
+				CORE_ADDR func)
+{
+  struct gdbarch *gdbarch = get_frame_arch (this_frame);
+  const int num_regs = gdbarch_num_regs (gdbarch);
+  int sp_cooked_regno = num_regs + MIPS_SP_REGNUM;
+  const CORE_ADDR sp = get_frame_register_signed (this_frame, sp_cooked_regno);
+  const CORE_ADDR sigcontext_base = sp + 48;
+  const struct mips_regnum *regs = mips_regnum (gdbarch);
+  int ireg;
+
+  trad_frame_set_reg_addr (this_cache, regs->pc + gdbarch_num_regs (gdbarch),
+                           sigcontext_base + SIGCONTEXT_PC_OFF);
+
+  for (ireg = 1; ireg < 32; ireg++)
+    trad_frame_set_reg_addr (this_cache, ireg + MIPS_ZERO_REGNUM + num_regs,
+                             sigcontext_base + SIGCONTEXT_REGS_OFF + ireg * 8);
+
+  for (ireg = 0; ireg < 32; ireg++)
+    trad_frame_set_reg_addr (this_cache, ireg + regs->fp0 + num_regs,
+                             sigcontext_base + SIGCONTEXT_FPREGS_OFF
+                               + ireg * 8);
+
+  trad_frame_set_reg_addr (this_cache, regs->fp_control_status + num_regs,
+                           sigcontext_base + SIGCONTEXT_FPCSR_OFF);
+
+  trad_frame_set_reg_addr (this_cache, regs->hi + num_regs,
+                           sigcontext_base + SIGCONTEXT_HI_OFF);
+
+  trad_frame_set_reg_addr (this_cache, regs->lo + num_regs,
+                           sigcontext_base + SIGCONTEXT_LO_OFF);
+
+  trad_frame_set_id (this_cache, frame_id_build (sigcontext_base, func));
+}
+
+/* The tramp_frame structure describing sigtramp frames on mips-irix N32.
+
+   Note that the list of instructions below is pretty much a pure dump
+   of function _sigtramp on mips-irix.  A few instructions are actually
+   not tested (mask set to 0), because a portion of these instructions
+   contain an address which changes due to relocation.  We could use
+   a smarter mask that checks the instrutction code alone, but given
+   the number of instructions already being checked, this seemed
+   unnecessary.  */
+
+static const struct tramp_frame mips_irix_n32_tramp_frame =
+{
+  SIGTRAMP_FRAME,
+  4,
+  {
+   { 0x3c0c8000, -1 }, /*    lui     t0,0x8000 */
+   { 0x27bdffd0, -1 }, /*    addiu   sp,sp,-48 */
+   { 0x008c6024, -1 }, /*    and     t0,a0,t0 */
+   { 0xffa40018, -1 }, /*    sd      a0,24(sp) */
+   { 0x00000000,  0 }, /*    beqz    t0,0xfaefcb8 <_sigtramp+40> */
+   { 0xffa60028, -1 }, /*    sd      a2,40(sp) */
+   { 0x01806027, -1 }, /*    nor     t0,t0,zero */
+   { 0xffa00020, -1 }, /*    sd      zero,32(sp) */
+   { 0x00000000,  0 }, /*    b       0xfaefcbc <_sigtramp+44> */
+   { 0x008c2024, -1 }, /*    and     a0,a0,t0 */
+   { 0xffa60020, -1 }, /*    sd      a2,32(sp) */
+   { 0x03e0c025, -1 }, /*    move    t8,ra */
+   { 0x00000000,  0 }, /*    bal     0xfaefcc8 <_sigtramp+56> */
+   { 0x00000000, -1 }, /*    nop */
+   { 0x3c0c0007, -1 }, /*    lui     t0,0x7 */
+   { 0x00e0c825, -1 }, /*    move    t9,a3 */
+   { 0x658c80fc, -1 }, /*    daddiu  t0,t0,-32516 */
+   { 0x019f602d, -1 }, /*    daddu   t0,t0,ra */
+   { 0x0300f825, -1 }, /*    move    ra,t8 */
+   { 0x8d8c9880, -1 }, /*    lw      t0,-26496(t0) */
+   { 0x8d8c0000, -1 }, /*    lw      t0,0(t0) */
+   { 0x8d8d0000, -1 }, /*    lw      t1,0(t0) */
+   { 0xffac0008, -1 }, /*    sd      t0,8(sp) */
+   { 0x0320f809, -1 }, /*    jalr    t9 */
+   { 0xffad0010, -1 }, /*    sd      t1,16(sp) */
+   { 0xdfad0010, -1 }, /*    ld      t1,16(sp) */
+   { 0xdfac0008, -1 }, /*    ld      t0,8(sp) */
+   { 0xad8d0000, -1 }, /*    sw      t1,0(t0) */
+   { 0xdfa40020, -1 }, /*    ld      a0,32(sp) */
+   { 0xdfa50028, -1 }, /*    ld      a1,40(sp) */
+   { 0xdfa60018, -1 }, /*    ld      a2,24(sp) */
+   { 0x24020440, -1 }, /*    li      v0,1088 */
+   { 0x0000000c, -1 }, /*    syscall */
+   { TRAMP_SENTINEL_INSN, -1 }
+  },
+  mips_irix_n32_tramp_frame_init
+};
+
 static void
 mips_irix_init_abi (struct gdbarch_info info,
                     struct gdbarch *gdbarch)
 {
   set_solib_ops (gdbarch, &irix_so_ops);
+  tramp_frame_prepend_unwinder (gdbarch, &mips_irix_n32_tramp_frame);
 }
 
 /* Provide a prototype to silence -Wmissing-prototypes.  */
-- 
1.5.4.3


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