Initial revision

1 files changed, 684 insertions, 0 deletions

diff --git a/gdb/findvar.c b/gdb/findvar.c
new file mode 100644
index 0000000..c674a54
--- /dev/null
+++ b/gdb/findvar.c
@@ -0,0 +1,684 @@
+/* Find a variable's value in memory, for GDB, the GNU debugger.
+   Copyright (C) 1986, 1987, 1989 Free Software Foundation, Inc.
+
+This file is part of GDB.
+
+GDB is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 1, or (at your option)
+any later version.
+
+GDB is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GDB; see the file COPYING.  If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#include <stdio.h>
+#include "defs.h"
+#include "param.h"
+#include "symtab.h"
+#include "frame.h"
+#include "value.h"
+#include "gdbcore.h"
+#include "inferior.h"
+#include "target.h"
+
+#if !defined (GET_SAVED_REGISTER)
+
+/* Return the address in which frame FRAME's value of register REGNUM
+   has been saved in memory.  Or return zero if it has not been saved.
+   If REGNUM specifies the SP, the value we return is actually
+   the SP value, not an address where it was saved.  */
+
+CORE_ADDR
+find_saved_register (frame, regnum)
+     FRAME frame;
+     int regnum;
+{
+  struct frame_info *fi;
+  struct frame_saved_regs saved_regs;
+
+  register FRAME frame1 = 0;
+  register CORE_ADDR addr = 0;
+
+  if (frame == 0)		/* No regs saved if want current frame */
+    return 0;
+
+#ifdef HAVE_REGISTER_WINDOWS
+  /* We assume that a register in a register window will only be saved
+     in one place (since the name changes and/or disappears as you go
+     towards inner frames), so we only call get_frame_saved_regs on
+     the current frame.  This is directly in contradiction to the
+     usage below, which assumes that registers used in a frame must be
+     saved in a lower (more interior) frame.  This change is a result
+     of working on a register window machine; get_frame_saved_regs
+     always returns the registers saved within a frame, within the
+     context (register namespace) of that frame. */
+
+  /* However, note that we don't want this to return anything if
+     nothing is saved (if there's a frame inside of this one).  Also,
+     callers to this routine asking for the stack pointer want the
+     stack pointer saved for *this* frame; this is returned from the
+     next frame.  */
+     
+
+  if (REGISTER_IN_WINDOW_P(regnum))
+    {
+      frame1 = get_next_frame (frame);
+      if (!frame1) return 0;	/* Registers of this frame are
+				   active.  */
+      
+      /* Get the SP from the next frame in; it will be this
+	 current frame.  */
+      if (regnum != SP_REGNUM)
+	frame1 = frame;	
+	  
+      fi = get_frame_info (frame1);
+      get_frame_saved_regs (fi, &saved_regs);
+      return saved_regs.regs[regnum];	/* ... which might be zero */
+    }
+#endif /* HAVE_REGISTER_WINDOWS */
+
+  /* Note that this next routine assumes that registers used in
+     frame x will be saved only in the frame that x calls and
+     frames interior to it.  This is not true on the sparc, but the
+     above macro takes care of it, so we should be all right. */
+  while (1)
+    {
+      QUIT;
+      frame1 = get_prev_frame (frame1);
+      if (frame1 == 0 || frame1 == frame)
+	break;
+      fi = get_frame_info (frame1);
+      get_frame_saved_regs (fi, &saved_regs);
+      if (saved_regs.regs[regnum])
+	addr = saved_regs.regs[regnum];
+    }
+
+  return addr;
+}
+
+/* Find register number REGNUM relative to FRAME and put its
+   (raw) contents in *RAW_BUFFER.  Set *OPTIMIZED if the variable
+   was optimized out (and thus can't be fetched).  Set *LVAL to
+   lval_memory, lval_register, or not_lval, depending on whether the
+   value was fetched from memory, from a register, or in a strange
+   and non-modifiable way (e.g. a frame pointer which was calculated
+   rather than fetched).  Set *ADDRP to the address, either in memory
+   on as a REGISTER_BYTE offset into the registers array.
+
+   Note that this implementation never sets *LVAL to not_lval.  But
+   it can be replaced by defining GET_SAVED_REGISTER and supplying
+   your own.
+
+   The argument RAW_BUFFER must point to aligned memory.  */
+void
+get_saved_register (raw_buffer, optimized, addrp, frame, regnum, lval)
+     char *raw_buffer;
+     int *optimized;
+     CORE_ADDR *addrp;
+     FRAME frame;
+     int regnum;
+     enum lval_type *lval;
+{
+  CORE_ADDR addr;
+  /* Normal systems don't optimize out things with register numbers.  */
+  if (optimized != NULL)
+    *optimized = 0;
+  addr = find_saved_register (frame, regnum);
+  if (addr != NULL)
+    {
+      if (lval != NULL)
+	*lval = lval_memory;
+      if (regnum == SP_REGNUM)
+	{
+	  if (raw_buffer != NULL)
+	    *(CORE_ADDR *)raw_buffer = addr;
+	  if (addrp != NULL)
+	    *addrp = 0;
+	  return;
+	}
+      if (raw_buffer != NULL)
+	read_memory (addr, raw_buffer, REGISTER_RAW_SIZE (regnum));
+    }
+  else
+    {
+      if (lval != NULL)
+	*lval = lval_register;
+      addr = REGISTER_BYTE (regnum);
+      if (raw_buffer != NULL)
+	read_register_gen (regnum, raw_buffer);
+    }
+  if (addrp != NULL)
+    *addrp = addr;
+}
+#endif /* GET_SAVED_REGISTER.  */
+
+/* Copy the bytes of register REGNUM, relative to the current stack frame,
+   into our memory at MYADDR, in target byte order.
+   The number of bytes copied is REGISTER_RAW_SIZE (REGNUM).
+
+   Returns 1 if could not be read, 0 if could.  */
+
+int
+read_relative_register_raw_bytes (regnum, myaddr)
+     int regnum;
+     char *myaddr;
+{
+  int optim;
+  if (regnum == FP_REGNUM && selected_frame)
+    {
+      bcopy (&FRAME_FP(selected_frame), myaddr, sizeof (CORE_ADDR));
+      SWAP_TARGET_AND_HOST (myaddr, sizeof (CORE_ADDR)); /* in target order */
+      return 0;
+    }
+
+  get_saved_register (myaddr, &optim, (CORE_ADDR) NULL, selected_frame,
+                      regnum, (enum lval_type *)NULL);
+  return optim;
+}
+
+/* Return a `value' with the contents of register REGNUM
+   in its virtual format, with the type specified by
+   REGISTER_VIRTUAL_TYPE.  */
+
+value
+value_of_register (regnum)
+     int regnum;
+{
+  CORE_ADDR addr;
+  int optim;
+  register value val;
+  char raw_buffer[MAX_REGISTER_RAW_SIZE];
+  char virtual_buffer[MAX_REGISTER_VIRTUAL_SIZE];
+  enum lval_type lval;
+
+  get_saved_register (raw_buffer, &optim, &addr,
+		      selected_frame, regnum, &lval);
+
+  target_convert_to_virtual (regnum, raw_buffer, virtual_buffer);
+  val = allocate_value (REGISTER_VIRTUAL_TYPE (regnum));
+  bcopy (virtual_buffer, VALUE_CONTENTS_RAW (val),
+	 REGISTER_VIRTUAL_SIZE (regnum));
+  VALUE_LVAL (val) = lval;
+  VALUE_ADDRESS (val) = addr;
+  VALUE_REGNO (val) = regnum;
+  VALUE_OPTIMIZED_OUT (val) = optim;
+  return val;
+}
+
+/* Low level examining and depositing of registers.
+
+   The caller is responsible for making
+   sure that the inferior is stopped before calling the fetching routines,
+   or it will get garbage.  (a change from GDB version 3, in which
+   the caller got the value from the last stop).  */
+
+/* Contents of the registers in target byte order.
+   We allocate some extra slop since we do a lot of bcopy's around `registers',
+   and failing-soft is better than failing hard.  */
+char registers[REGISTER_BYTES + /* SLOP */ 256];
+
+/* Nonzero if that register has been fetched.  */
+char register_valid[NUM_REGS];
+
+/* Indicate that registers may have changed, so invalidate the cache.  */
+void
+registers_changed ()
+{
+  int i;
+  for (i = 0; i < NUM_REGS; i++)
+    register_valid[i] = 0;
+}
+
+/* Indicate that all registers have been fetched, so mark them all valid.  */
+void
+registers_fetched ()
+{
+  int i;
+  for (i = 0; i < NUM_REGS; i++)
+    register_valid[i] = 1;
+}
+
+/* Copy LEN bytes of consecutive data from registers
+   starting with the REGBYTE'th byte of register data
+   into memory at MYADDR.  */
+
+void
+read_register_bytes (regbyte, myaddr, len)
+     int regbyte;
+     char *myaddr;
+     int len;
+{
+  /* Fetch all registers.  */
+  int i;
+  for (i = 0; i < NUM_REGS; i++)
+    if (!register_valid[i])
+      {
+	target_fetch_registers (-1);
+	break;
+      }
+  if (myaddr != NULL)
+    bcopy (&registers[regbyte], myaddr, len);
+}
+
+/* Read register REGNO into memory at MYADDR, which must be large enough
+   for REGISTER_RAW_BYTES (REGNO).  If the register is known to be the
+   size of a CORE_ADDR or smaller, read_register can be used instead.  */
+void
+read_register_gen (regno, myaddr)
+     int regno;
+     char *myaddr;
+{
+  if (!register_valid[regno])
+    target_fetch_registers (regno);
+  bcopy (&registers[REGISTER_BYTE (regno)], myaddr, REGISTER_RAW_SIZE (regno));
+}
+
+/* Copy LEN bytes of consecutive data from memory at MYADDR
+   into registers starting with the REGBYTE'th byte of register data.  */
+
+void
+write_register_bytes (regbyte, myaddr, len)
+     int regbyte;
+     char *myaddr;
+     int len;
+{
+  /* Make sure the entire registers array is valid.  */
+  read_register_bytes (0, (char *)NULL, REGISTER_BYTES);
+  bcopy (myaddr, &registers[regbyte], len);
+  target_store_registers (-1);
+}
+
+/* Return the contents of register REGNO, regarding it as an integer.  */
+
+CORE_ADDR
+read_register (regno)
+     int regno;
+{
+  int reg;
+  if (!register_valid[regno])
+    target_fetch_registers (regno);
+  /* FIXME, this loses when REGISTER_RAW_SIZE (regno) != sizeof (int) */
+  reg = *(int *) &registers[REGISTER_BYTE (regno)];
+  SWAP_TARGET_AND_HOST (&reg, sizeof (int));
+  return reg;
+}
+
+/* Registers we shouldn't try to store.  */
+#if !defined (CANNOT_STORE_REGISTER)
+#define CANNOT_STORE_REGISTER(regno) 0
+#endif
+
+/* Store VALUE in the register number REGNO, regarded as an integer.  */
+
+void
+write_register (regno, val)
+     int regno, val;
+{
+  /* On the sparc, writing %g0 is a no-op, so we don't even want to change
+     the registers array if something writes to this register.  */
+  if (CANNOT_STORE_REGISTER (regno))
+    return;
+
+  SWAP_TARGET_AND_HOST (&val, sizeof (int));
+
+  target_prepare_to_store ();
+
+  register_valid [regno] = 1;
+  /* FIXME, this loses when REGISTER_RAW_SIZE (regno) != sizeof (int) */
+  /* FIXME, this depends on REGISTER_BYTE (regno) being aligned for host */
+  *(int *) &registers[REGISTER_BYTE (regno)] = val;
+
+  target_store_registers (regno);
+}
+
+/* Record that register REGNO contains VAL.
+   This is used when the value is obtained from the inferior or core dump,
+   so there is no need to store the value there.  */
+
+void
+supply_register (regno, val)
+     int regno;
+     char *val;
+{
+  register_valid[regno] = 1;
+  bcopy (val, &registers[REGISTER_BYTE (regno)], REGISTER_RAW_SIZE (regno));
+}
+
+/* Given a struct symbol for a variable,
+   and a stack frame id, read the value of the variable
+   and return a (pointer to a) struct value containing the value. 
+   If the variable cannot be found, return a zero pointer.  */
+
+value
+read_var_value (var, frame)
+     register struct symbol *var;
+     FRAME frame;
+{
+  register value v;
+  struct frame_info *fi;
+  struct type *type = SYMBOL_TYPE (var);
+  CORE_ADDR addr;
+  int val;
+  register int len;
+
+  v = allocate_value (type);
+  VALUE_LVAL (v) = lval_memory;	/* The most likely possibility.  */
+  len = TYPE_LENGTH (type);
+
+  if (frame == 0) frame = selected_frame;
+
+  switch (SYMBOL_CLASS (var))
+    {
+    case LOC_CONST:
+      val = SYMBOL_VALUE (var);
+      bcopy (&val, VALUE_CONTENTS_RAW (v), len);
+      SWAP_TARGET_AND_HOST (VALUE_CONTENTS_RAW (v), len);
+      VALUE_LVAL (v) = not_lval;
+      return v;
+
+    case LOC_LABEL:
+      addr = SYMBOL_VALUE_ADDRESS (var);
+      bcopy (&addr, VALUE_CONTENTS_RAW (v), len);
+      SWAP_TARGET_AND_HOST (VALUE_CONTENTS_RAW (v), len);
+      VALUE_LVAL (v) = not_lval;
+      return v;
+
+    case LOC_CONST_BYTES:
+      addr = SYMBOL_VALUE_ADDRESS (var);
+      bcopy (addr, VALUE_CONTENTS_RAW (v), len);
+      VALUE_LVAL (v) = not_lval;
+      return v;
+
+    case LOC_STATIC:
+    case LOC_EXTERNAL:
+      addr = SYMBOL_VALUE_ADDRESS (var);
+      break;
+
+/* Nonzero if a struct which is located in a register or a LOC_ARG
+   really contains
+   the address of the struct, not the struct itself.  GCC_P is nonzero
+   if the function was compiled with GCC.  */
+#if !defined (REG_STRUCT_HAS_ADDR)
+#define REG_STRUCT_HAS_ADDR(gcc_p) 0
+#endif
+
+    case LOC_ARG:
+      fi = get_frame_info (frame);
+      addr = FRAME_ARGS_ADDRESS (fi);
+      if (!addr) {
+	return 0;
+      }
+      addr += SYMBOL_VALUE (var);
+      break;
+      
+    case LOC_REF_ARG:
+      fi = get_frame_info (frame);
+      addr = FRAME_ARGS_ADDRESS (fi);
+      if (!addr) {
+	return 0;
+      }
+      addr += SYMBOL_VALUE (var);
+      addr = read_memory_integer (addr, sizeof (CORE_ADDR));
+      break;
+      
+    case LOC_LOCAL:
+    case LOC_LOCAL_ARG:
+      fi = get_frame_info (frame);
+      addr = SYMBOL_VALUE (var) + FRAME_LOCALS_ADDRESS (fi);
+      break;
+
+    case LOC_TYPEDEF:
+      error ("Cannot look up value of a typedef");
+      break;
+
+    case LOC_BLOCK:
+      VALUE_ADDRESS (v) = BLOCK_START (SYMBOL_BLOCK_VALUE (var));
+      return v;
+
+    case LOC_REGISTER:
+    case LOC_REGPARM:
+      {
+	struct block *b = get_frame_block (frame);
+
+	v = value_from_register (type, SYMBOL_VALUE (var), frame);
+
+	if (REG_STRUCT_HAS_ADDR(b->gcc_compile_flag)
+	    && TYPE_CODE (type) == TYPE_CODE_STRUCT)
+	  addr = *(CORE_ADDR *)VALUE_CONTENTS (v);
+	else
+	  return v;
+      }
+      break;
+
+    default:
+      error ("Cannot look up value of a botched symbol.");
+      break;
+    }
+
+  VALUE_ADDRESS (v) = addr;
+  VALUE_LAZY (v) = 1;
+  return v;
+}
+
+/* Return a value of type TYPE, stored in register REGNUM, in frame
+   FRAME. */
+
+value
+value_from_register (type, regnum, frame)
+     struct type *type;
+     int regnum;
+     FRAME frame;
+{
+  char raw_buffer [MAX_REGISTER_RAW_SIZE];
+  char virtual_buffer[MAX_REGISTER_VIRTUAL_SIZE];
+  CORE_ADDR addr;
+  int optim;
+  value v = allocate_value (type);
+  int len = TYPE_LENGTH (type);
+  char *value_bytes = 0;
+  int value_bytes_copied = 0;
+  int num_storage_locs;
+  enum lval_type lval;
+
+  VALUE_REGNO (v) = regnum;
+
+  num_storage_locs = (len > REGISTER_VIRTUAL_SIZE (regnum) ?
+		      ((len - 1) / REGISTER_RAW_SIZE (regnum)) + 1 :
+		      1);
+
+  if (num_storage_locs > 1)
+    {
+      /* Value spread across multiple storage locations.  */
+      
+      int local_regnum;
+      int mem_stor = 0, reg_stor = 0;
+      int mem_tracking = 1;
+      CORE_ADDR last_addr = 0;
+      CORE_ADDR first_addr;
+
+      value_bytes = (char *) alloca (len + MAX_REGISTER_RAW_SIZE);
+
+      /* Copy all of the data out, whereever it may be.  */
+
+      for (local_regnum = regnum;
+	   value_bytes_copied < len;
+	   (value_bytes_copied += REGISTER_RAW_SIZE (local_regnum),
+	    ++local_regnum))
+	{
+	  get_saved_register (value_bytes + value_bytes_copied,
+			      &optim,
+			      &addr,
+			      frame,
+			      local_regnum,
+			      &lval);
+	  if (lval == lval_register)
+	    reg_stor++;
+	  else
+	    {
+	      mem_stor++;
+
+	      if (regnum == local_regnum)
+		first_addr = addr;
+	      
+	      mem_tracking =
+		(mem_tracking
+		 && (regnum == local_regnum
+		     || addr == last_addr));
+	    }
+	  last_addr = addr;
+	}
+
+      if ((reg_stor && mem_stor)
+	  || (mem_stor && !mem_tracking))
+	/* Mixed storage; all of the hassle we just went through was
+	   for some good purpose.  */
+	{
+	  VALUE_LVAL (v) = lval_reg_frame_relative;
+	  VALUE_FRAME (v) = FRAME_FP (frame);
+	  VALUE_FRAME_REGNUM (v) = regnum;
+	}
+      else if (mem_stor)
+	{
+	  VALUE_LVAL (v) = lval_memory;
+	  VALUE_ADDRESS (v) = first_addr;
+	}
+      else if (reg_stor)
+	{
+	  VALUE_LVAL (v) = lval_register;
+	  VALUE_ADDRESS (v) = first_addr;
+	}
+      else
+	fatal ("value_from_register: Value not stored anywhere!");
+
+      VALUE_OPTIMIZED_OUT (v) = optim;
+
+      /* Any structure stored in more than one register will always be
+	 an integral number of registers.  Otherwise, you'd need to do
+	 some fiddling with the last register copied here for little
+	 endian machines.  */
+
+      /* Copy into the contents section of the value.  */
+      bcopy (value_bytes, VALUE_CONTENTS_RAW (v), len);
+
+      return v;
+    }
+
+  /* Data is completely contained within a single register.  Locate the
+     register's contents in a real register or in core;
+     read the data in raw format.  */
+
+  get_saved_register (raw_buffer, &optim, &addr, frame, regnum, &lval);
+  VALUE_OPTIMIZED_OUT (v) = optim;
+  VALUE_LVAL (v) = lval;
+  VALUE_ADDRESS (v) = addr;
+  
+  /* Convert the raw contents to virtual contents.
+     (Just copy them if the formats are the same.)  */
+  
+  target_convert_to_virtual (regnum, raw_buffer, virtual_buffer);
+  
+  if (REGISTER_CONVERTIBLE (regnum))
+    {
+      /* When the raw and virtual formats differ, the virtual format
+	 corresponds to a specific data type.  If we want that type,
+	 copy the data into the value.
+	 Otherwise, do a type-conversion.  */
+      
+      if (type != REGISTER_VIRTUAL_TYPE (regnum))
+	{
+	  /* eg a variable of type `float' in a 68881 register
+	     with raw type `extended' and virtual type `double'.
+	     Fetch it as a `double' and then convert to `float'.  */
+	  v = allocate_value (REGISTER_VIRTUAL_TYPE (regnum));
+	  bcopy (virtual_buffer, VALUE_CONTENTS_RAW (v), len);
+	  v = value_cast (type, v);
+	}
+      else
+	bcopy (virtual_buffer, VALUE_CONTENTS_RAW (v), len);
+    }
+  else
+    {
+      /* Raw and virtual formats are the same for this register.  */
+
+#if TARGET_BYTE_ORDER == BIG_ENDIAN
+      if (len < REGISTER_RAW_SIZE (regnum))
+	{
+  	  /* Big-endian, and we want less than full size.  */
+	  VALUE_OFFSET (v) = REGISTER_RAW_SIZE (regnum) - len;
+	}
+#endif
+
+      bcopy (virtual_buffer + VALUE_OFFSET (v),
+	     VALUE_CONTENTS_RAW (v), len);
+    }
+  
+  return v;
+}
+
+/* Given a struct symbol for a variable,
+   and a stack frame id, 
+   return a (pointer to a) struct value containing the variable's address.  */
+
+value
+locate_var_value (var, frame)
+     register struct symbol *var;
+     FRAME frame;
+{
+  CORE_ADDR addr = 0;
+  struct type *type = SYMBOL_TYPE (var);
+  struct type *result_type;
+  value lazy_value;
+
+  /* Evaluate it first; if the result is a memory address, we're fine.
+     Lazy evaluation pays off here. */
+
+  lazy_value = read_var_value (var, frame);
+  if (lazy_value == 0)
+    error ("Address of \"%s\" is unknown.", SYMBOL_NAME (var));
+
+  if (VALUE_LAZY (lazy_value))
+    {
+      addr = VALUE_ADDRESS (lazy_value);
+
+      /* C++: The "address" of a reference should yield the address
+       * of the object pointed to. So force an extra de-reference. */
+
+      if (TYPE_CODE (type) == TYPE_CODE_REF)
+	{
+	  char *buf = alloca (TYPE_LENGTH (type));
+	  read_memory (addr, buf, TYPE_LENGTH (type));
+	  addr = unpack_long (type, buf);
+	  type = TYPE_TARGET_TYPE (type);
+	}
+
+      /* Address of an array is of the type of address of it's elements.  */
+      result_type =
+	lookup_pointer_type (TYPE_CODE (type) == TYPE_CODE_ARRAY ?
+			     TYPE_TARGET_TYPE (type) : type);
+
+      return value_cast (result_type,
+			 value_from_long (builtin_type_long, (LONGEST) addr));
+    }
+
+  /* Not a memory address; check what the problem was.  */
+  switch (VALUE_LVAL (lazy_value)) 
+    {
+    case lval_register:
+    case lval_reg_frame_relative:
+      error ("Address requested for identifier \"%s\" which is in a register.",
+	     SYMBOL_NAME (var));
+      break;
+
+    default:
+      error ("Can't take address of \"%s\" which isn't an lvalue.",
+	     SYMBOL_NAME (var));
+      break;
+    }
+  return 0;  /* For lint -- never reached */
+}