Start to implement it for real.

(Logical change 1.162)

src/x86/Gresume-x86.c

@@ -1,5 +1,5 @@
 /* libunwind - a platform-independent unwind library
-   Copyright (c) 2002-2003 Hewlett-Packard Development Company, L.P.
+   Copyright (c) 2002-2004 Hewlett-Packard Development Company, L.P.
 	Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
 
 This file is part of libunwind.
@@ -32,101 +32,123 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
 HIDDEN inline int
 x86_local_resume (unw_addr_space_t as, unw_cursor_t *cursor, void *arg)
 {
-#if 1
+#if defined(__linux)
-  printf ("%s: implement me\n", __FUNCTION__);
-  return -UNW_EINVAL;
-#else
   struct cursor *c = (struct cursor *) cursor;
-  unw_fpreg_t fpval;
+  ucontext_t *uc = c->dwarf.as_arg;
-  ucontext_t *uc = arg;
-  unw_word_t val, sol;
-  int i, ret;
-# define SET_NAT(n)						\
-  do								\
-    {								\
-      ret = x86_access_reg (c, UNW_X86_NAT + (n), &val, 0);	\
-      if (ret < 0)						\
-	return ret;						\
-      if (val)							\
-	uc->uc_mcontext.sc_nat |= (unw_word_t) 1 << n;		\
-    }								\
-  while (0)
-# define SET_REG(f, r)				\
-  do						\
-    {						\
-      ret = x86_get (c, c->r, &val);		\
-      if (ret < 0)				\
-	return ret;				\
-      uc->uc_mcontext.f = val;			\
-    }						\
-  while (0)
-# define SET_FPREG(f, r)				\
-  do							\
-    {							\
-      ret = x86_getfp (c, c->r, &fpval);		\
-      if (ret < 0)					\
-	return ret;					\
-      uc->uc_mcontext.f.u.bits[0] = fpval.raw.bits[0];	\
-      uc->uc_mcontext.f.u.bits[1] = fpval.raw.bits[1];	\
-    }							\
-  while (0)
 
-  /* ensure c->pi is up-to-date: */
+  /* Ensure c->pi is up-to-date.  On x86, it's relatively common to be
-  if ((ret = x86_make_proc_info (c)) < 0)
+     missing DWARF unwind info.  We don't want to fail in that case,
+     because the frame-chain still would let us do a backtrace at
+     least.  */
+  dwarf_make_proc_info (&c->dwarf);
+
+  if (unlikely (c->sigcontext_format != X86_SCF_NONE))
+    {
+      struct sigcontext *sc = (struct sigcontext *) c->sigcontext_addr;
+
+#if 0
+      /* We're returning to a frame that was (either directly or
+	 indirectly) interrupted by a signal.  We have to restore
+	 _both_ "preserved" and "scratch" registers.  That doesn't
+	 leave us any registers to work with, and the only way we can
+	 achieve this is by doing a sigreturn().
+
+	 Note: it might be tempting to think that we don't have to
+	 restore the scratch registers when returning to a frame that
+	 was indirectly interrupted by a signal.  However, that is not
+	 safe because that frame and its descendants could have been
+	 using a special convention that stores "preserved" state in
+	 scratch registers.  For example, the Linux fsyscall
+	 convention does this with r11 (to save ar.pfs) and b6 (to
+	 save "rp"). */
+
+      sc->sc_gr[12] = c->psp;
+      c->psp = c->sigcontext_addr - c->sigcontext_off;
+
+      /* Clear the "in-syscall" flag, because in general we won't be
+	 returning to the interruption-point and we need all registers
+	 restored.  */
+      sc->sc_flags &= ~IA64_SC_FLAG_IN_SYSCALL;
+      sc->sc_ip = c->ip;
+      sc->sc_cfm = c->cfm & (((unw_word_t) 1 << 38) - 1);
+      sc->sc_pr = (c->pr & ~PR_SCRATCH) | (sc->sc_pr & ~PR_PRESERVED);
+      if ((ret = ia64_get (c, c->loc[IA64_REG_PFS], &sc->sc_ar_pfs)) < 0
+	  || (ret = ia64_get (c, c->loc[IA64_REG_FPSR], &sc->sc_ar_fpsr)) < 0
+	  || (ret = ia64_get (c, c->loc[IA64_REG_UNAT], &sc->sc_ar_unat)) < 0)
 	return ret;
 
-  SET_REG (sc_ar_pfs, pfs_loc);
+      sc->sc_gr[1] = c->pi.gp;
-  SET_REG (sc_br[0], ip_loc);
+      if (c->eh_valid_mask & 0x1) sc->sc_gr[15] = c->eh_args[0];
-  SET_REG (sc_pr, pr_loc);
+      if (c->eh_valid_mask & 0x2) sc->sc_gr[16] = c->eh_args[1];
-  SET_REG (sc_ar_rnat, rnat_loc);
+      if (c->eh_valid_mask & 0x4) sc->sc_gr[17] = c->eh_args[2];
-  SET_REG (sc_ar_lc, lc_loc);
+      if (c->eh_valid_mask & 0x8) sc->sc_gr[18] = c->eh_args[3];
-  SET_REG (sc_ar_fpsr, fpsr_loc);
-
-  SET_REG (sc_gr[4], r4_loc); SET_REG(sc_gr[5], r5_loc);
-  SET_REG (sc_gr[6], r6_loc); SET_REG(sc_gr[7], r7_loc);
-  uc->uc_mcontext.sc_nat = 0;
-  SET_NAT (4); SET_NAT(5);
-  SET_NAT (6); SET_NAT(7);
-
-  SET_REG (sc_br[1], b1_loc);
-  SET_REG (sc_br[2], b2_loc);
-  SET_REG (sc_br[3], b3_loc);
-  SET_REG (sc_br[4], b4_loc);
-  SET_REG (sc_br[5], b5_loc);
-  SET_FPREG (sc_fr[2], f2_loc);
-  SET_FPREG (sc_fr[3], f3_loc);
-  SET_FPREG (sc_fr[4], f4_loc);
-  SET_FPREG (sc_fr[5], f5_loc);
-  for (i = 16; i < 32; ++i)
-    SET_FPREG (sc_fr[i], fr_loc[i - 16]);
-
-  if (c->is_signal_frame)
-    abort ();	/* XXX this needs to be fixed... */
-
-  /* Account for the fact that __x86_install_context() returns via
-     br.ret, which will decrement bsp by size-of-locals.  */
-  sol = (uc->uc_mcontext.sc_ar_pfs >> 7) & 0x7f;
-  uc->uc_mcontext.sc_ar_bsp = x86_rse_skip_regs (c->bsp, sol);
-
-  uc->uc_mcontext.sc_flags = 0;
-  uc->uc_mcontext.sc_gr[1] = c->pi.gp;
-  uc->uc_mcontext.sc_gr[12] = c->psp;
-
-  __x86_install_context (uc, c->eh_args[0], c->eh_args[1], c->eh_args[2],
-			 c->eh_args[3]);
 #endif
+
+      Debug (9, "resuming at ip=%x via sigreturn(%p)\n", c->dwarf.ip, sc);
+      sigreturn (sc);
+    }
+  else
+    {
+      Debug (9, "resuming at ip=%x via setcontext()\n", c->dwarf.ip);
+      setcontext (uc);
+    }
+#else
+# warning Implement me!
+#endif
+  return -UNW_EINVAL;
 }
 
 #endif /* !UNW_REMOTE_ONLY */
 
+/* This routine is responsible for copying the register values in
+   cursor C and establishing them as the current machine state. */
+
+static inline int
+establish_machine_state (struct cursor *c)
+{
+  int (*access_reg) (unw_addr_space_t, unw_regnum_t, unw_word_t *,
+		     int write, void *);
+  int (*access_fpreg) (unw_addr_space_t, unw_regnum_t, unw_fpreg_t *,
+		       int write, void *);
+  unw_addr_space_t as = c->dwarf.as;
+  void *arg = c->dwarf.as_arg;
+  unw_fpreg_t fpval;
+  unw_word_t val;
+  int reg;
+
+  access_reg = as->acc.access_reg;
+  access_fpreg = as->acc.access_fpreg;
+
+  Debug (8, "copying out cursor state\n");
+
+  for (reg = 0; reg < UNW_REG_LAST; ++reg)
+    {
+Debug (16, "copying %s\n", unw_regname (reg));
+      if (unw_is_fpreg (reg))
+	{
+	  if (tdep_access_fpreg (c, reg, &fpval, 0) >= 0)
+	    (*access_fpreg) (as, reg, &fpval, 1, arg);
+	}
+      else
+	{
+	  if (tdep_access_reg (c, reg, &val, 0) >= 0)
+	    (*access_reg) (as, reg, &val, 1, arg);
+	}
+    }
+  return 0;
+}
+
 PROTECTED int
 unw_resume (unw_cursor_t *cursor)
 {
   struct cursor *c = (struct cursor *) cursor;
+  int ret;
 
-#ifdef UNW_LOCAL_ONLY
+  Debug (2, "(cursor=%p)\n", c);
-  return x86_local_resume (c->dwarf.as, cursor, c->dwarf.as_arg);
+
-#else
+  if ((ret = establish_machine_state (c)) < 0)
-  return (*c->dwarf.as->acc.resume) (c->dwarf.as, cursor, c->dwarf.as_arg);
+    return ret;
-#endif
+
+  return (*c->dwarf.as->acc.resume) (c->dwarf.as, (unw_cursor_t *) c,
+				     c->dwarf.as_arg);
 }

src/x86/Gstep-x86.c

@@ -32,6 +32,8 @@ unw_step (unw_cursor_t *cursor)
   struct cursor *c = (struct cursor *) cursor;
   int ret, i;
 
+  Debug (2, "(cursor=%p)\n", c);
+
   /* Try DWARF-based unwinding... */
   ret = dwarf_step (&c->dwarf);
 
@@ -41,8 +43,7 @@ unw_step (unw_cursor_t *cursor)
 	 or skip over the signal trampoline.  */
       struct dwarf_loc ebp_loc, eip_loc;
 
-      Debug (14, "dwarf_step() failed (ret=%d), trying frame-chain\n",
+      Debug (13, "dwarf_step() failed (ret=%d), trying frame-chain\n", ret);
-	     ret);
 
       if (unw_is_signal_frame (cursor))
 	{
@@ -53,6 +54,7 @@ unw_step (unw_cursor_t *cursor)
 	     followed by a struct sigcontext.  With SA_SIGINFO, the
 	     arguments consist a signal number, a siginfo *, and a
 	     ucontext *. */
+	  unw_word_t sigcontext_addr;
 	  unw_word_t siginfo_ptr_addr = c->dwarf.cfa + 4;
 	  unw_word_t sigcontext_ptr_addr = c->dwarf.cfa + 8;
 	  unw_word_t siginfo_ptr, sigcontext_ptr;
@@ -70,10 +72,8 @@ unw_step (unw_cursor_t *cursor)
 	      || sigcontext_ptr > c->dwarf.cfa + 256)
 	    {
 	      /* Not plausible for SA_SIGINFO signal */
-	      unw_word_t sigcontext_addr = c->dwarf.cfa + 4;
+	      c->sigcontext_format = X86_SCF_LINUX_SIGFRAME;
-	      esp_loc = DWARF_LOC (sigcontext_addr + LINUX_SC_ESP_OFF, 0);
+	      c->sigcontext_addr = sigcontext_addr = c->dwarf.cfa + 4;
-	      ebp_loc = DWARF_LOC (sigcontext_addr + LINUX_SC_EBP_OFF, 0);
-	      eip_loc = DWARF_LOC (sigcontext_addr + LINUX_SC_EIP_OFF, 0);
 	    }
 	  else
 	    {
@@ -82,10 +82,13 @@ unw_step (unw_cursor_t *cursor)
 		 least fs and _fsh are always zero for linux, so it is
 		 not just unlikely, but impossible that we would end
 		 up here. */
-	      esp_loc = DWARF_LOC (sigcontext_ptr + LINUX_UC_ESP_OFF, 0);
+	      c->sigcontext_format = X86_SCF_LINUX_RT_SIGFRAME;
-	      ebp_loc = DWARF_LOC (sigcontext_ptr + LINUX_UC_EBP_OFF, 0);
+	      c->sigcontext_addr = sigcontext_ptr;
-	      eip_loc = DWARF_LOC (sigcontext_ptr + LINUX_UC_EIP_OFF, 0);
+	      sigcontext_addr = sigcontext_ptr + LINUX_UC_MCONTEXT_OFF;
 	    }
+	  esp_loc = DWARF_LOC (sigcontext_addr + LINUX_SC_ESP_OFF, 0);
+	  ebp_loc = DWARF_LOC (sigcontext_addr + LINUX_SC_EBP_OFF, 0);
+	  eip_loc = DWARF_LOC (sigcontext_addr + LINUX_SC_EIP_OFF, 0);
 	  ret = dwarf_get (&c->dwarf, esp_loc, &c->dwarf.cfa);
 	  if (ret < 0)
 	    return 0;
@@ -96,9 +99,8 @@ unw_step (unw_cursor_t *cursor)
 	  if (ret < 0)
 	    return ret;
 
-	  Debug (14, "[EBP=0x%lx] = 0x%lx\n",
+	  Debug (13, "[EBP=0x%x] = 0x%xx\n", DWARF_GET_LOC (c->dwarf.loc[EBP]),
-		 (long) DWARF_GET_LOC (c->dwarf.loc[EBP]),
+		 c->dwarf.cfa);
-		 (long) c->dwarf.cfa);
 
 	  ebp_loc = DWARF_LOC (c->dwarf.cfa, 0);
 	  eip_loc = DWARF_LOC (c->dwarf.cfa + 4, 0);