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[PATCH] Expose register state from dwarf2-frame.c


This moves some defenitions into dwarf2-frame.h that will be needed
when we let the architecture pre-initialize the register state for the
DWARF2 CFI unwinder.  I made sure all exposed definitions are prefixed
with dwarf2_frame_/DWARF2_FRAME_.

Committed,

Mark


Index: ChangeLog
from  Mark Kettenis  <kettenis@gnu.org>

	* dwarf2-frame.h: Update copyright.
	(enum dwarf2_frame_reg_rule): New.
	(struct dwarf2_frame_state_reg): New.
	(dwarf2_frame_sniffer, dwarf2_frame_base_sniffer): Make extern.
	* dwarf2-frame.c: Update copyright.
	(enum dwarf2_reg_rule): Remove.
	(struct dwarf2_frame_state): Remove defenition of `struct
	dwarf2_frame_state_reg'.
	(read_reg): Call get_frame_arch to get the architecture instead of
	using CURRENT_GDBARCH.
	(execute_cfa_program): Prefix old `enum dwarf2_reg_rule' tags with
	DWARF2_FRAME_.
	(dwarf2_frame_init_reg): New function.
	(dwarf2_frame_cache): Call get_frame_arch to get the architecture
	instead of using CURRENT_GDBARCH.  Call dwarf2_frame_init_reg to
	initialize the register state.  Prefix old `enum dwarf2_reg_rule'
	tags with DWARF2_FRAME_.
	(dwarf2_frame_prev_register): Call get_frame_arch to get the
	architecture instead of using CURRENT_GDBARCH.  Prefix old `enum
	dwarf2_reg_rule' tags with DWARF2_FRAME_.

Index: dwarf2-frame.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2-frame.c,v
retrieving revision 1.27
diff -u -p -r1.27 dwarf2-frame.c
--- dwarf2-frame.c 2 Feb 2004 22:00:14 -0000 1.27
+++ dwarf2-frame.c 7 Feb 2004 14:40:14 -0000
@@ -1,6 +1,6 @@
 /* Frame unwinder for frames with DWARF Call Frame Information.
 
-   Copyright 2003 Free Software Foundation, Inc.
+   Copyright 2003, 2004 Free Software Foundation, Inc.
 
    Contributed by Mark Kettenis.
 
@@ -97,49 +97,13 @@ static struct dwarf2_fde *dwarf2_frame_f
 
 /* Structure describing a frame state.  */
 
-enum dwarf2_reg_rule
-{
-  /* Make certain that 0 maps onto the correct enum value; the
-     corresponding structure is being initialized using memset zero.
-     This indicates that CFI didn't provide any information at all
-     about a register, leaving how to obtain its value totally
-     unspecified.  */
-  REG_UNSPECIFIED = 0,
-
-  /* The term "undefined" comes from the DWARF2 CFI spec which this
-     code is moddeling; it indicates that the register's value is
-     "undefined".  GCC uses the less formal term "unsaved".  Its
-     definition is a combination of REG_UNDEFINED and REG_UNSPECIFIED.
-     The failure to differentiate the two helps explain a few problems
-     with the CFI generated by GCC.  */
-  REG_UNDEFINED,
-  REG_SAVED_OFFSET,
-  REG_SAVED_REG,
-  REG_SAVED_EXP,
-  REG_SAME_VALUE,
-
-  /* These aren't defined by the DWARF2 CFI specification, but are
-     used internally by GDB.  */
-  REG_RA,			/* Return Address.  */
-  REG_CFA			/* Call Frame Address.  */
-};
-
 struct dwarf2_frame_state
 {
   /* Each register save state can be described in terms of a CFA slot,
      another register, or a location expression.  */
   struct dwarf2_frame_state_reg_info
   {
-    struct dwarf2_frame_state_reg
-    {
-      union {
-	LONGEST offset;
-	ULONGEST reg;
-	unsigned char *exp;
-      } loc;
-      ULONGEST exp_len;
-      enum dwarf2_reg_rule how;
-    } *reg;
+    struct dwarf2_frame_state_reg *reg;
     int num_regs;
 
     /* Used to implement DW_CFA_remember_state.  */
@@ -242,12 +206,13 @@ static CORE_ADDR
 read_reg (void *baton, int reg)
 {
   struct frame_info *next_frame = (struct frame_info *) baton;
+  struct gdbarch *gdbarch = get_frame_arch (next_frame);
   int regnum;
   char *buf;
 
   regnum = DWARF2_REG_TO_REGNUM (reg);
 
-  buf = (char *) alloca (register_size (current_gdbarch, regnum));
+  buf = (char *) alloca (register_size (gdbarch, regnum));
   frame_unwind_register (next_frame, regnum, buf);
   return extract_typed_address (buf, builtin_type_void_data_ptr);
 }
@@ -321,7 +286,7 @@ execute_cfa_program (unsigned char *insn
 	  insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
 	  offset = utmp * fs->data_align;
 	  dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
-	  fs->regs.reg[reg].how = REG_SAVED_OFFSET;
+	  fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
 	  fs->regs.reg[reg].loc.offset = offset;
 	}
       else if ((insn & 0xc0) == DW_CFA_restore)
@@ -361,7 +326,7 @@ execute_cfa_program (unsigned char *insn
 	      insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
 	      offset = utmp * fs->data_align;
 	      dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
-	      fs->regs.reg[reg].how = REG_SAVED_OFFSET;
+	      fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
 	      fs->regs.reg[reg].loc.offset = offset;
 	      break;
 
@@ -375,20 +340,20 @@ execute_cfa_program (unsigned char *insn
 	    case DW_CFA_undefined:
 	      insn_ptr = read_uleb128 (insn_ptr, insn_end, &reg);
 	      dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
-	      fs->regs.reg[reg].how = REG_UNDEFINED;
+	      fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNDEFINED;
 	      break;
 
 	    case DW_CFA_same_value:
 	      insn_ptr = read_uleb128 (insn_ptr, insn_end, &reg);
 	      dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
-	      fs->regs.reg[reg].how = REG_SAME_VALUE;
+	      fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAME_VALUE;
 	      break;
 
 	    case DW_CFA_register:
 	      insn_ptr = read_uleb128 (insn_ptr, insn_end, &reg);
 	      insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
 	      dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
-	      fs->regs.reg[reg].how = REG_SAVED_REG;
+	      fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
 	      fs->regs.reg[reg].loc.reg = utmp;
 	      break;
 
@@ -448,7 +413,7 @@ execute_cfa_program (unsigned char *insn
 	      insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
 	      fs->regs.reg[reg].loc.exp = insn_ptr;
 	      fs->regs.reg[reg].exp_len = utmp;
-	      fs->regs.reg[reg].how = REG_SAVED_EXP;
+	      fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_EXP;
 	      insn_ptr += utmp;
 	      break;
 
@@ -457,7 +422,7 @@ execute_cfa_program (unsigned char *insn
 	      insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
 	      offset += fs->data_align;
 	      dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
-	      fs->regs.reg[reg].how = REG_SAVED_OFFSET;
+	      fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
 	      fs->regs.reg[reg].loc.offset = offset;
 	      break;
 
@@ -500,10 +465,47 @@ struct dwarf2_frame_cache
   struct dwarf2_frame_state_reg *reg;
 };
 
+/* Initialize the register state REG.  If we have a register that acts
+   as a program counter, mark it as a destination for the return
+   address.  If we have a register that serves as the stack pointer,
+   arrange for it to be filled with the call frame address (CFA).  The
+   other registers are marked as unspecified.
+
+   We copy the return address to the program counter, since many parts
+   in GDB assume that it is possible to get the return address by
+   unwind the program counter register.  However, on ISA's with a
+   dedicated return address register, the CFI usually only contains
+   information to unwind that return address register.
+
+   The reason we're treating the stack pointer special here is because
+   in many cases GCC doesn't emit CFI for the stack pointer and
+   implicitly assumes that it is equal to the CFA.  This makes some
+   sense since the DWARF specification (version 3, draft 8, p. 102)
+   says that:
+
+   "Typically, the CFA is defined to be the value of the stack pointer
+   at the call site in the previous frame (which may be different from
+   its value on entry to the current frame)."
+
+   However, this isn't true for all platforms supported by GCC
+   (e.g. IBM S/390 and zSeries).  For those targets we should override
+   the defaults given here.  */
+
+static void
+dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
+		       struct dwarf2_frame_state_reg *reg)
+{
+  if (regnum == PC_REGNUM)
+    reg->how = DWARF2_FRAME_REG_RA;
+  else if (regnum == SP_REGNUM)
+    reg->how = DWARF2_FRAME_REG_CFA;
+}
+
 static struct dwarf2_frame_cache *
 dwarf2_frame_cache (struct frame_info *next_frame, void **this_cache)
 {
   struct cleanup *old_chain;
+  struct gdbarch *gdbarch = get_frame_arch (next_frame);
   const int num_regs = NUM_REGS + NUM_PSEUDO_REGS;
   struct dwarf2_frame_cache *cache;
   struct dwarf2_frame_state *fs;
@@ -575,43 +577,12 @@ dwarf2_frame_cache (struct frame_info *n
       internal_error (__FILE__, __LINE__, "Unknown CFA rule.");
     }
 
-  /* Initialize the register rules.  If we have a register that acts
-     as a program counter, mark it as a destination for the return
-     address.  If we have a register that serves as the stack pointer,
-     arrange for it to be filled with the call frame address (CFA).
-     The other registers are marked as unspecified.
-
-     We copy the return address to the program counter, since many
-     parts in GDB assume that it is possible to get the return address
-     by unwind the program counter register.  However, on ISA's with a
-     dedicated return address register, the CFI usually only contains
-     information to unwind that return address register.
-
-     The reason we're treating the stack pointer special here is
-     because in many cases GCC doesn't emit CFI for the stack pointer
-     and implicitly assumes that it is equal to the CFA.  This makes
-     some sense since the DWARF specification (version 3, draft 8,
-     p. 102) says that:
-
-     "Typically, the CFA is defined to be the value of the stack
-     pointer at the call site in the previous frame (which may be
-     different from its value on entry to the current frame)."
-
-     However, this isn't true for all platforms supported by GCC
-     (e.g. IBM S/390 and zSeries).  For those targets we should
-     override the defaults given here.  */
+  /* Initialize the register state.  */
   {
     int regnum;
 
     for (regnum = 0; regnum < num_regs; regnum++)
-      {
-	if (regnum == PC_REGNUM)
-	  cache->reg[regnum].how = REG_RA;
-	else if (regnum == SP_REGNUM)
-	  cache->reg[regnum].how = REG_CFA;
-	else
-	  cache->reg[regnum].how = REG_UNSPECIFIED;
-      }
+      dwarf2_frame_init_reg (gdbarch, regnum, &cache->reg[regnum]);
   }
 
   /* Go through the DWARF2 CFI generated table and save its register
@@ -644,7 +615,7 @@ dwarf2_frame_cache (struct frame_info *n
 	   problems when a debug info register falls outside of the
 	   table.  We need a way of iterating through all the valid
 	   DWARF2 register numbers.  */
-	if (fs->regs.reg[column].how == REG_UNSPECIFIED)
+	if (fs->regs.reg[column].how == DWARF2_FRAME_REG_UNSPECIFIED)
 	  complaint (&symfile_complaints,
 		     "Incomplete CFI data; unspecified registers at 0x%s",
 		     paddr (fs->pc));
@@ -653,14 +624,17 @@ dwarf2_frame_cache (struct frame_info *n
       }
   }
 
-  /* Eliminate any REG_RA rules.  */
+  /* Eliminate any DWARF2_FRAME_REG_RA rules.  */
   {
     int regnum;
 
     for (regnum = 0; regnum < num_regs; regnum++)
       {
-	if (cache->reg[regnum].how == REG_RA)
+	if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
 	  {
+	    struct dwarf2_frame_state_reg *retaddr_reg =
+	      &fs->regs.reg[fs->retaddr_column];
+
 	    /* It seems rather bizarre to specify an "empty" column as
                the return adress column.  However, this is exactly
                what GCC does on some targets.  It turns out that GCC
@@ -669,13 +643,13 @@ dwarf2_frame_cache (struct frame_info *n
                Incidentally, that's how should treat a return address
                column specifying "same value" too.  */
 	    if (fs->retaddr_column < fs->regs.num_regs
-		&& fs->regs.reg[fs->retaddr_column].how != REG_UNSPECIFIED
-		&& fs->regs.reg[fs->retaddr_column].how != REG_SAME_VALUE)
-	      cache->reg[regnum] = fs->regs.reg[fs->retaddr_column];
+		&& retaddr_reg->how != DWARF2_FRAME_REG_UNSPECIFIED
+		&& retaddr_reg->how != DWARF2_FRAME_REG_SAME_VALUE)
+	      cache->reg[regnum] = *retaddr_reg;
 	    else
 	      {
 		cache->reg[regnum].loc.reg = fs->retaddr_column;
-		cache->reg[regnum].how = REG_SAVED_REG;
+		cache->reg[regnum].how = DWARF2_FRAME_REG_SAVED_REG;
 	      }
 	  }
       }
@@ -703,12 +677,13 @@ dwarf2_frame_prev_register (struct frame
 			    enum lval_type *lvalp, CORE_ADDR *addrp,
 			    int *realnump, void *valuep)
 {
+  struct gdbarch *gdbarch = get_frame_arch (next_frame);
   struct dwarf2_frame_cache *cache =
     dwarf2_frame_cache (next_frame, this_cache);
 
   switch (cache->reg[regnum].how)
     {
-    case REG_UNDEFINED:
+    case DWARF2_FRAME_REG_UNDEFINED:
       /* If CFI explicitly specified that the value isn't defined,
 	 mark it as optimized away; the value isn't available.  */
       *optimizedp = 1;
@@ -724,7 +699,7 @@ dwarf2_frame_prev_register (struct frame
 	}
       break;
 
-    case REG_SAVED_OFFSET:
+    case DWARF2_FRAME_REG_SAVED_OFFSET:
       *optimizedp = 0;
       *lvalp = lval_memory;
       *addrp = cache->cfa + cache->reg[regnum].loc.offset;
@@ -732,18 +707,17 @@ dwarf2_frame_prev_register (struct frame
       if (valuep)
 	{
 	  /* Read the value in from memory.  */
-	  read_memory (*addrp, valuep,
-		       register_size (current_gdbarch, regnum));
+	  read_memory (*addrp, valuep, register_size (gdbarch, regnum));
 	}
       break;
 
-    case REG_SAVED_REG:
+    case DWARF2_FRAME_REG_SAVED_REG:
       regnum = DWARF2_REG_TO_REGNUM (cache->reg[regnum].loc.reg);
       frame_register_unwind (next_frame, regnum,
 			     optimizedp, lvalp, addrp, realnump, valuep);
       break;
 
-    case REG_SAVED_EXP:
+    case DWARF2_FRAME_REG_SAVED_EXP:
       *optimizedp = 0;
       *lvalp = lval_memory;
       *addrp = execute_stack_op (cache->reg[regnum].loc.exp,
@@ -753,12 +727,11 @@ dwarf2_frame_prev_register (struct frame
       if (valuep)
 	{
 	  /* Read the value in from memory.  */
-	  read_memory (*addrp, valuep,
-		       register_size (current_gdbarch, regnum));
+	  read_memory (*addrp, valuep, register_size (gdbarch, regnum));
 	}
       break;
 
-    case REG_UNSPECIFIED:
+    case DWARF2_FRAME_REG_UNSPECIFIED:
       /* GCC, in its infinite wisdom decided to not provide unwind
 	 information for registers that are "same value".  Since
 	 DWARF2 (3 draft 7) doesn't define such behavior, said
@@ -770,12 +743,12 @@ dwarf2_frame_prev_register (struct frame
 			     optimizedp, lvalp, addrp, realnump, valuep);
       break;
 
-    case REG_SAME_VALUE:
+    case DWARF2_FRAME_REG_SAME_VALUE:
       frame_register_unwind (next_frame, regnum,
 			     optimizedp, lvalp, addrp, realnump, valuep);
       break;
 
-    case REG_CFA:
+    case DWARF2_FRAME_REG_CFA:
       *optimizedp = 0;
       *lvalp = not_lval;
       *addrp = 0;
Index: dwarf2-frame.h
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2-frame.h,v
retrieving revision 1.3
diff -u -p -r1.3 dwarf2-frame.h
--- dwarf2-frame.h 18 Jul 2003 19:01:14 -0000 1.3
+++ dwarf2-frame.h 7 Feb 2004 14:40:14 -0000
@@ -1,6 +1,6 @@
 /* Frame unwinder for frames with DWARF Call Frame Information.
 
-   Copyright 2003 Free Software Foundation, Inc.
+   Copyright 2003, 2004 Free Software Foundation, Inc.
 
    Contributed by Mark Kettenis.
 
@@ -27,15 +27,61 @@
 struct objfile;
 struct frame_info;
 
+/* Register rule.  */
+
+enum dwarf2_frame_reg_rule
+{
+  /* Make certain that 0 maps onto the correct enum value; the
+     corresponding structure is being initialized using memset zero.
+     This indicates that CFI didn't provide any information at all
+     about a register, leaving how to obtain its value totally
+     unspecified.  */
+  DWARF2_FRAME_REG_UNSPECIFIED = 0,
+
+  /* The term "undefined" comes from the DWARF2 CFI spec which this
+     code is moddeling; it indicates that the register's value is
+     "undefined".  GCC uses the less formal term "unsaved".  Its
+     definition is a combination of REG_UNDEFINED and REG_UNSPECIFIED.
+     The failure to differentiate the two helps explain a few problems
+     with the CFI generated by GCC.  */
+  DWARF2_FRAME_REG_UNDEFINED,
+  DWARF2_FRAME_REG_SAVED_OFFSET,
+  DWARF2_FRAME_REG_SAVED_REG,
+  DWARF2_FRAME_REG_SAVED_EXP,
+  DWARF2_FRAME_REG_SAME_VALUE,
+
+  /* These aren't defined by the DWARF2 CFI specification, but are
+     used internally by GDB.  */
+  DWARF2_FRAME_REG_RA,		/* Return Address.  */
+  DWARF2_FRAME_REG_CFA		/* Call Frame Address.  */
+};
+
+/* Register state.  */
+
+struct dwarf2_frame_state_reg
+{
+  /* Each register save state can be described in terms of a CFA slot,
+     another register, or a location expression.  */
+  union {
+    LONGEST offset;
+    ULONGEST reg;
+    unsigned char *exp;
+  } loc;
+  ULONGEST exp_len;
+  enum dwarf2_frame_reg_rule how;
+};
+
 /* Return the frame unwind methods for the function that contains PC,
    or NULL if it can't be handled by DWARF CFI frame unwinder.  */
 
-const struct frame_unwind *dwarf2_frame_sniffer (struct frame_info *next_frame);
+extern const struct frame_unwind *
+  dwarf2_frame_sniffer (struct frame_info *next_frame);
 
 /* Return the frame base methods for the function that contains PC, or
    NULL if it can't be handled by the DWARF CFI frame unwinder.  */
 
-const struct frame_base *dwarf2_frame_base_sniffer (struct frame_info *next_frame);
+extern const struct frame_base *
+  dwarf2_frame_base_sniffer (struct frame_info *next_frame);
 
 /* Register the DWARF CFI for OBJFILE.  */
 


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