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-rw-r--r--gdb/dwarf2expr.c687
1 files changed, 687 insertions, 0 deletions
diff --git a/gdb/dwarf2expr.c b/gdb/dwarf2expr.c
new file mode 100644
index 00000000000..df6fc73ceb7
--- /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. */
+
+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. */
+
+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:;
+ }
+}
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