Based on a patch from Daniel Berlin (dberlin@dberlin.org).

	* symtab.h: Add opaque declarations of struct axs_value and
	struct agent_expr.
	(enum address_class): Add LOC_COMPUTED and LOC_COMPUTED_ARG.
	(struct location_funcs): New type.
	(struct symbol): Add "loc" to aux_value.
	(SYMBOL_LOCATION_BATON, SYMBOL_LOCATION_FUNCS): New macros.
	* dwarf2read.c: Include "dwarf2expr.h".
	(dwarf2_symbol_mark_computed): New function.
	(read_func_scope): Use it.
	(var_decode_location): New function.
	(new_symbol): Use it.
	* dwarf2expr.c, dwarf2expr.h, dwarf2loc.c, dwarf2loc.h: New files.

	* Makefile.in (SFILES): Add dwarf2loc.c and dwarf2expr.c.
	(dwarf2expr_h, dwarf2loc_h): New variables.
	(COMMON_OBS): Add dwarf2expr.o and dwarf2loc.o.
	(dwarf2expr.o, dwarf2loc.o): New rules.
	(dwarf2read.o): Add $(dwarf2expr_h) and $(dwarf2loc_h).
	* buildsym.c (finish_block): Handle LOC_COMPUTED and
	LOC_COMPUTED_ARG.
	* findvar.c (symbol_read_needs_frame, read_var_value): Likewise.
	* m2-exp.y (yylex): Likewise.
	* printcmd.c (address_info, print_frame_args): Likewise.
	* stack.c (print_block_frame_locals, print_frame_arg_vars): Likewise.
	* symmisc.c (print_symbol, print_partial_symbols): Likewise.
	* ada-lang.c (ada_resolve_subexp, symtab_for_sym)
	(ada_add_block_symbols, fill_in_ada_prototype): Likewise.
	* symtab.c (lookup_block_symbol): Likewise.

1 files changed, 687 insertions, 0 deletions

diff --git a/gdb/dwarf2expr.c b/gdb/dwarf2expr.c
new file mode 100644
index 0000000..02e246f
--- /dev/null
+++ b/gdb/dwarf2expr.c
@@ -0,0 +1,687 @@
+/* Dwarf2 Expression Evaluator
+   Copyright 2001, 2002, 2003 Free Software Foundation, Inc.
+   Contributed by Daniel Berlin (dan@dberlin.org)
+
+   This file is part of GDB.
+
+   This program 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 2 of the License, or
+   (at your option) any later version.
+
+   This program 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 this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include "defs.h"
+#include "symtab.h"
+#include "gdbtypes.h"
+#include "value.h"
+#include "gdbcore.h"
+#include "elf/dwarf2.h"
+#include "dwarf2expr.h"
+
+/* Local prototypes.  */
+
+static void execute_stack_op (struct dwarf_expr_context *,
+			      unsigned char *, unsigned char *);
+
+/* Create a new context for the expression evaluator.  */
+
+struct dwarf_expr_context *
+new_dwarf_expr_context ()
+{
+  struct dwarf_expr_context *retval;
+  retval = xcalloc (1, sizeof (struct dwarf_expr_context));
+  retval->stack_len = 10;
+  retval->stack = xmalloc (10 * sizeof (CORE_ADDR));
+  return retval;
+}
+
+/* Release the memory allocated to CTX.  */
+
+void
+free_dwarf_expr_context (struct dwarf_expr_context *ctx)
+{
+  xfree (ctx->stack);
+  xfree (ctx);
+}
+
+/* Expand the memory allocated to CTX's stack to contain at least
+   NEED more elements than are currently used.  */
+
+static void
+dwarf_expr_grow_stack (struct dwarf_expr_context *ctx, size_t need)
+{
+  if (ctx->stack_len + need > ctx->stack_allocated)
+    {
+      size_t templen = ctx->stack_len * 2;
+      while (templen < (ctx->stack_len + need))
+	   templen *= 2;
+      ctx->stack = xrealloc (ctx->stack,
+			     templen * sizeof (CORE_ADDR));
+      ctx->stack_allocated = templen;
+    }
+}
+
+/* Push VALUE onto CTX's stack.  */
+
+void
+dwarf_expr_push (struct dwarf_expr_context *ctx, CORE_ADDR value)
+{
+  dwarf_expr_grow_stack (ctx, 1);
+  ctx->stack[ctx->stack_len++] = value;
+}
+
+/* Pop the top item off of CTX's stack.  */
+
+void
+dwarf_expr_pop (struct dwarf_expr_context *ctx)
+{
+  if (ctx->stack_len <= 0)
+    error ("dwarf expression stack underflow");
+  ctx->stack_len--;
+}
+
+/* Retrieve the N'th item on CTX's stack.  */
+
+CORE_ADDR
+dwarf_expr_fetch (struct dwarf_expr_context *ctx, int n)
+{
+  if (ctx->stack_len < n)
+     error ("Asked for position %d of stack, stack only has %d elements on it\n",
+	    n, ctx->stack_len);
+  return ctx->stack[ctx->stack_len - (1 + n)];
+
+}
+
+/* Evaluate the expression at ADDR (LEN bytes long) using the context
+   CTX.  */
+
+void
+dwarf_expr_eval (struct dwarf_expr_context *ctx, unsigned char *addr,
+		 size_t len)
+{
+  execute_stack_op (ctx, addr, addr + len);
+}
+
+/* Decode the unsigned LEB128 constant at BUF into the variable pointed to
+   by R, and return the new value of BUF.  Verify that it doesn't extend
+   past BUF_END.  */
+
+static unsigned char *
+read_uleb128 (unsigned char *buf, unsigned char *buf_end, ULONGEST * r)
+{
+  unsigned shift = 0;
+  ULONGEST result = 0;
+  unsigned char byte;
+
+  while (1)
+    {
+      if (buf >= buf_end)
+	error ("read_uleb128: Corrupted DWARF expression.");
+
+      byte = *buf++;
+      result |= (byte & 0x7f) << shift;
+      if ((byte & 0x80) == 0)
+	break;
+      shift += 7;
+    }
+  *r = result;
+  return buf;
+}
+
+/* Decode the signed LEB128 constant at BUF into the variable pointed to
+   by R, and return the new value of BUF.  Verify that it doesn't extend
+   past BUF_END.  */
+
+static unsigned char *
+read_sleb128 (unsigned char *buf, unsigned char *buf_end, LONGEST * r)
+{
+  unsigned shift = 0;
+  LONGEST result = 0;
+  unsigned char byte;
+
+  while (1)
+    {
+      if (buf >= buf_end)
+	error ("read_sleb128: Corrupted DWARF expression.");
+
+      byte = *buf++;
+      result |= (byte & 0x7f) << shift;
+      shift += 7;
+      if ((byte & 0x80) == 0)
+	break;
+    }
+  if (shift < (sizeof (*r) * 8) && (byte & 0x40) != 0)
+    result |= -(1 << shift);
+
+  *r = result;
+  return buf;
+}
+
+/* Read an address from BUF, and verify that it doesn't extend past
+   BUF_END.  The address is returned, and *BYTES_READ is set to the
+   number of bytes read from BUF.  */
+
+static CORE_ADDR
+read_address (unsigned char *buf, unsigned char *buf_end, int *bytes_read)
+{
+  CORE_ADDR result;
+
+  if (buf_end - buf < TARGET_ADDR_BIT / TARGET_CHAR_BIT)
+    error ("read_address: Corrupted DWARF expression.");
+
+  *bytes_read = TARGET_ADDR_BIT / TARGET_CHAR_BIT;
+  result = extract_address (buf, TARGET_ADDR_BIT / TARGET_CHAR_BIT);
+  return result;
+}
+
+/* Return the type of an address, for unsigned arithmetic.  */
+
+static struct type *
+unsigned_address_type (void)
+{
+  switch (TARGET_ADDR_BIT / TARGET_CHAR_BIT)
+    {
+    case 2:
+      return builtin_type_uint16;
+    case 4:
+      return builtin_type_uint32;
+    case 8:
+      return builtin_type_uint64;
+    default:
+      internal_error (__FILE__, __LINE__,
+		      "Unsupported address size.\n");
+    }
+}
+
+/* Return the type of an address, for signed arithmetic.  */
+
+static struct type *
+signed_address_type (void)
+{
+  switch (TARGET_ADDR_BIT / TARGET_CHAR_BIT)
+    {
+    case 2:
+      return builtin_type_int16;
+    case 4:
+      return builtin_type_int32;
+    case 8:
+      return builtin_type_int64;
+    default:
+      internal_error (__FILE__, __LINE__,
+		      "Unsupported address size.\n");
+    }
+}
+
+/* The engine for the expression evaluator.  Using the context in CTX,
+   evaluate the expression between OP_PTR and OP_END.  */
+
+static void
+execute_stack_op (struct dwarf_expr_context *ctx, unsigned char *op_ptr,
+		  unsigned char *op_end)
+{
+  while (op_ptr < op_end)
+    {
+      enum dwarf_location_atom op = *op_ptr++;
+      CORE_ADDR result, memaddr;
+      ULONGEST uoffset, reg;
+      LONGEST offset;
+      int bytes_read;
+      enum lval_type expr_lval;
+
+      ctx->in_reg = 0;
+
+      switch (op)
+	{
+	case DW_OP_lit0:
+	case DW_OP_lit1:
+	case DW_OP_lit2:
+	case DW_OP_lit3:
+	case DW_OP_lit4:
+	case DW_OP_lit5:
+	case DW_OP_lit6:
+	case DW_OP_lit7:
+	case DW_OP_lit8:
+	case DW_OP_lit9:
+	case DW_OP_lit10:
+	case DW_OP_lit11:
+	case DW_OP_lit12:
+	case DW_OP_lit13:
+	case DW_OP_lit14:
+	case DW_OP_lit15:
+	case DW_OP_lit16:
+	case DW_OP_lit17:
+	case DW_OP_lit18:
+	case DW_OP_lit19:
+	case DW_OP_lit20:
+	case DW_OP_lit21:
+	case DW_OP_lit22:
+	case DW_OP_lit23:
+	case DW_OP_lit24:
+	case DW_OP_lit25:
+	case DW_OP_lit26:
+	case DW_OP_lit27:
+	case DW_OP_lit28:
+	case DW_OP_lit29:
+	case DW_OP_lit30:
+	case DW_OP_lit31:
+	  result = op - DW_OP_lit0;
+	  break;
+
+	case DW_OP_addr:
+	  result = read_address (op_ptr, op_end, &bytes_read);
+	  op_ptr += bytes_read;
+	  break;
+
+	case DW_OP_const1u:
+	  result = extract_unsigned_integer (op_ptr, 1);
+	  op_ptr += 1;
+	  break;
+	case DW_OP_const1s:
+	  result = extract_signed_integer (op_ptr, 1);
+	  op_ptr += 1;
+	  break;
+	case DW_OP_const2u:
+	  result = extract_unsigned_integer (op_ptr, 2);
+	  op_ptr += 2;
+	  break;
+	case DW_OP_const2s:
+	  result = extract_signed_integer (op_ptr, 2);
+	  op_ptr += 2;
+	  break;
+	case DW_OP_const4u:
+	  result = extract_unsigned_integer (op_ptr, 4);
+	  op_ptr += 4;
+	  break;
+	case DW_OP_const4s:
+	  result = extract_signed_integer (op_ptr, 4);
+	  op_ptr += 4;
+	  break;
+	case DW_OP_const8u:
+	  result = extract_unsigned_integer (op_ptr, 8);
+	  op_ptr += 8;
+	  break;
+	case DW_OP_const8s:
+	  result = extract_signed_integer (op_ptr, 8);
+	  op_ptr += 8;
+	  break;
+	case DW_OP_constu:
+	  op_ptr = read_uleb128 (op_ptr, op_end, &uoffset);
+	  result = uoffset;
+	  break;
+	case DW_OP_consts:
+	  op_ptr = read_sleb128 (op_ptr, op_end, &offset);
+	  result = offset;
+	  break;
+
+	/* The DW_OP_reg operations are required to occur alone in
+	   location expressions.  */
+	case DW_OP_reg0:
+	case DW_OP_reg1:
+	case DW_OP_reg2:
+	case DW_OP_reg3:
+	case DW_OP_reg4:
+	case DW_OP_reg5:
+	case DW_OP_reg6:
+	case DW_OP_reg7:
+	case DW_OP_reg8:
+	case DW_OP_reg9:
+	case DW_OP_reg10:
+	case DW_OP_reg11:
+	case DW_OP_reg12:
+	case DW_OP_reg13:
+	case DW_OP_reg14:
+	case DW_OP_reg15:
+	case DW_OP_reg16:
+	case DW_OP_reg17:
+	case DW_OP_reg18:
+	case DW_OP_reg19:
+	case DW_OP_reg20:
+	case DW_OP_reg21:
+	case DW_OP_reg22:
+	case DW_OP_reg23:
+	case DW_OP_reg24:
+	case DW_OP_reg25:
+	case DW_OP_reg26:
+	case DW_OP_reg27:
+	case DW_OP_reg28:
+	case DW_OP_reg29:
+	case DW_OP_reg30:
+	case DW_OP_reg31:
+	  /* NOTE: in the presence of DW_OP_piece this check is incorrect.  */
+	  if (op_ptr != op_end)
+	    error ("DWARF-2 expression error: DW_OP_reg operations must be "
+		   "used alone.");
+
+	  /* FIXME drow/2003-02-21: This call to read_reg could be pushed
+	     into the evaluator's caller by changing the semantics for in_reg.
+	     Then we wouldn't need to return an lval_type and a memaddr.  */
+	  result = (ctx->read_reg) (ctx->baton, op - DW_OP_reg0, &expr_lval,
+				    &memaddr);
+
+	  if (expr_lval == lval_register)
+	    {
+	      ctx->regnum = op - DW_OP_reg0;
+	      ctx->in_reg = 1;
+	    }
+	  else
+	    result = memaddr;
+
+	  break;
+
+	case DW_OP_regx:
+	  op_ptr = read_uleb128 (op_ptr, op_end, &reg);
+	  if (op_ptr != op_end)
+	    error ("DWARF-2 expression error: DW_OP_reg operations must be "
+		   "used alone.");
+
+	  result = (ctx->read_reg) (ctx->baton, reg, &expr_lval, &memaddr);
+
+	  if (expr_lval == lval_register)
+	    {
+	      ctx->regnum = reg;
+	      ctx->in_reg = 1;
+	    }
+	  else
+	    result = memaddr;
+
+	  break;
+
+	case DW_OP_breg0:
+	case DW_OP_breg1:
+	case DW_OP_breg2:
+	case DW_OP_breg3:
+	case DW_OP_breg4:
+	case DW_OP_breg5:
+	case DW_OP_breg6:
+	case DW_OP_breg7:
+	case DW_OP_breg8:
+	case DW_OP_breg9:
+	case DW_OP_breg10:
+	case DW_OP_breg11:
+	case DW_OP_breg12:
+	case DW_OP_breg13:
+	case DW_OP_breg14:
+	case DW_OP_breg15:
+	case DW_OP_breg16:
+	case DW_OP_breg17:
+	case DW_OP_breg18:
+	case DW_OP_breg19:
+	case DW_OP_breg20:
+	case DW_OP_breg21:
+	case DW_OP_breg22:
+	case DW_OP_breg23:
+	case DW_OP_breg24:
+	case DW_OP_breg25:
+	case DW_OP_breg26:
+	case DW_OP_breg27:
+	case DW_OP_breg28:
+	case DW_OP_breg29:
+	case DW_OP_breg30:
+	case DW_OP_breg31:
+	  {
+	    op_ptr = read_sleb128 (op_ptr, op_end, &offset);
+	    result = (ctx->read_reg) (ctx->baton, op - DW_OP_breg0,
+				      &expr_lval, &memaddr);
+	    result += offset;
+	  }
+	  break;
+	case DW_OP_bregx:
+	  {
+	    op_ptr = read_uleb128 (op_ptr, op_end, &reg);
+	    op_ptr = read_sleb128 (op_ptr, op_end, &offset);
+	    result = (ctx->read_reg) (ctx->baton, reg, &expr_lval, &memaddr);
+	    result += offset;
+	  }
+	  break;
+	case DW_OP_fbreg:
+	  {
+	    unsigned char *datastart;
+	    size_t datalen;
+	    unsigned int before_stack_len;
+
+	    op_ptr = read_sleb128 (op_ptr, op_end, &offset);
+	    /* Rather than create a whole new context, we simply
+	       record the stack length before execution, then reset it
+	       afterwards, effectively erasing whatever the recursive
+	       call put there.  */
+	    before_stack_len = ctx->stack_len;
+	    (ctx->get_frame_base) (ctx->baton, &datastart, &datalen);
+	    dwarf_expr_eval (ctx, datastart, datalen);
+	    result = dwarf_expr_fetch (ctx, 0);
+	    if (! ctx->in_reg)
+	      {
+		char *buf = alloca (TARGET_ADDR_BIT / TARGET_CHAR_BIT);
+		int bytes_read;
+
+		(ctx->read_mem) (ctx->baton, buf, result,
+				 TARGET_ADDR_BIT / TARGET_CHAR_BIT);
+		result = read_address (buf,
+				       buf + TARGET_ADDR_BIT / TARGET_CHAR_BIT,
+				       &bytes_read);
+	      }
+	    result = result + offset;
+	    ctx->stack_len = before_stack_len;
+	    ctx->in_reg = 0;
+	  }
+	  break;
+	case DW_OP_dup:
+	  result = dwarf_expr_fetch (ctx, 0);
+	  break;
+
+	case DW_OP_drop:
+	  dwarf_expr_pop (ctx);
+	  goto no_push;
+
+	case DW_OP_pick:
+	  offset = *op_ptr++;
+	  result = dwarf_expr_fetch (ctx, offset);
+	  break;
+
+	case DW_OP_over:
+	  result = dwarf_expr_fetch (ctx, 1);
+	  break;
+
+	case DW_OP_rot:
+	  {
+	    CORE_ADDR t1, t2, t3;
+
+	    if (ctx->stack_len < 3)
+	       error ("Not enough elements for DW_OP_rot. Need 3, have %d\n",
+		      ctx->stack_len);
+	    t1 = ctx->stack[ctx->stack_len - 1];
+	    t2 = ctx->stack[ctx->stack_len - 2];
+	    t3 = ctx->stack[ctx->stack_len - 3];
+	    ctx->stack[ctx->stack_len - 1] = t2;
+	    ctx->stack[ctx->stack_len - 2] = t3;
+	    ctx->stack[ctx->stack_len - 3] = t1;
+	    goto no_push;
+	  }
+
+	case DW_OP_deref:
+	case DW_OP_deref_size:
+	case DW_OP_abs:
+	case DW_OP_neg:
+	case DW_OP_not:
+	case DW_OP_plus_uconst:
+	  /* Unary operations.  */
+	  result = dwarf_expr_fetch (ctx, 0);
+	  dwarf_expr_pop (ctx);
+
+	  switch (op)
+	    {
+	    case DW_OP_deref:
+	      {
+		char *buf = alloca (TARGET_ADDR_BIT / TARGET_CHAR_BIT);
+		int bytes_read;
+
+		(ctx->read_mem) (ctx->baton, buf, result,
+				 TARGET_ADDR_BIT / TARGET_CHAR_BIT);
+		result = read_address (buf,
+				       buf + TARGET_ADDR_BIT / TARGET_CHAR_BIT,
+				       &bytes_read);
+	      }
+	      break;
+
+	    case DW_OP_deref_size:
+	      {
+		char *buf = alloca (TARGET_ADDR_BIT / TARGET_CHAR_BIT);
+		int bytes_read;
+
+		(ctx->read_mem) (ctx->baton, buf, result, *op_ptr++);
+		result = read_address (buf,
+				       buf + TARGET_ADDR_BIT / TARGET_CHAR_BIT,
+				       &bytes_read);
+	      }
+	      break;
+
+	    case DW_OP_abs:
+	      if ((signed int) result < 0)
+		result = -result;
+	      break;
+	    case DW_OP_neg:
+	      result = -result;
+	      break;
+	    case DW_OP_not:
+	      result = ~result;
+	      break;
+	    case DW_OP_plus_uconst:
+	      op_ptr = read_uleb128 (op_ptr, op_end, &reg);
+	      result += reg;
+	      break;
+	    }
+	  break;
+
+	case DW_OP_and:
+	case DW_OP_div:
+	case DW_OP_minus:
+	case DW_OP_mod:
+	case DW_OP_mul:
+	case DW_OP_or:
+	case DW_OP_plus:
+	case DW_OP_shl:
+	case DW_OP_shr:
+	case DW_OP_shra:
+	case DW_OP_xor:
+	case DW_OP_le:
+	case DW_OP_ge:
+	case DW_OP_eq:
+	case DW_OP_lt:
+	case DW_OP_gt:
+	case DW_OP_ne:
+	  {
+	    /* Binary operations.  Use the value engine to do computations in
+	       the right width.  */
+	    CORE_ADDR first, second;
+	    enum exp_opcode binop;
+	    struct value *val1, *val2;
+
+	    second = dwarf_expr_fetch (ctx, 0);
+	    dwarf_expr_pop (ctx);
+
+	    first = dwarf_expr_fetch (ctx, 1);
+	    dwarf_expr_pop (ctx);
+
+	    val1 = value_from_longest (unsigned_address_type (), first);
+	    val2 = value_from_longest (unsigned_address_type (), second);
+
+	    switch (op)
+	      {
+	      case DW_OP_and:
+		binop = BINOP_BITWISE_AND;
+		break;
+	      case DW_OP_div:
+		binop = BINOP_DIV;
+	      case DW_OP_minus:
+		binop = BINOP_SUB;
+		break;
+	      case DW_OP_mod:
+		binop = BINOP_MOD;
+		break;
+	      case DW_OP_mul:
+		binop = BINOP_MUL;
+		break;
+	      case DW_OP_or:
+		binop = BINOP_BITWISE_IOR;
+		break;
+	      case DW_OP_plus:
+		binop = BINOP_ADD;
+		break;
+	      case DW_OP_shl:
+		binop = BINOP_LSH;
+		break;
+	      case DW_OP_shr:
+		binop = BINOP_RSH;
+	      case DW_OP_shra:
+		binop = BINOP_RSH;
+		val1 = value_from_longest (signed_address_type (), first);
+		break;
+	      case DW_OP_xor:
+		binop = BINOP_BITWISE_XOR;
+		break;
+	      case DW_OP_le:
+		binop = BINOP_LEQ;
+		break;
+	      case DW_OP_ge:
+		binop = BINOP_GEQ;
+		break;
+	      case DW_OP_eq:
+		binop = BINOP_EQUAL;
+		break;
+	      case DW_OP_lt:
+		binop = BINOP_LESS;
+		break;
+	      case DW_OP_gt:
+		binop = BINOP_GTR;
+		break;
+	      case DW_OP_ne:
+		binop = BINOP_NOTEQUAL;
+		break;
+	      default:
+		internal_error (__FILE__, __LINE__,
+				"Can't be reached.");
+	      }
+	    result = value_as_long (value_binop (val1, val2, binop));
+	  }
+	  break;
+
+	case DW_OP_GNU_push_tls_address:
+	  result = dwarf_expr_fetch (ctx, 0);
+	  dwarf_expr_pop (ctx);
+	  result = (ctx->get_tls_address) (ctx->baton, result);
+	  break;
+
+	case DW_OP_skip:
+	  offset = extract_signed_integer (op_ptr, 2);
+	  op_ptr += 2;
+	  op_ptr += offset;
+	  goto no_push;
+
+	case DW_OP_bra:
+	  offset = extract_signed_integer (op_ptr, 2);
+	  op_ptr += 2;
+	  if (dwarf_expr_fetch (ctx, 0) != 0)
+	    op_ptr += offset;
+	  dwarf_expr_pop (ctx);
+	  goto no_push;
+
+	case DW_OP_nop:
+	  goto no_push;
+
+	default:
+	  error ("Unhandled dwarf expression opcode");
+	}
+
+      /* Most things push a result value.  */
+      dwarf_expr_push (ctx, result);
+    no_push:;
+    }
+}