gdb/gdb-implptr-64bit-2of2.patch

http://sourceware.org/ml/gdb-patches/2011-09/msg00451.html
Subject: [patch 2/2] Fix DW_OP_GNU_implicit_pointer for DWARF32 v3+ on 64-bit arches

Hi,

on 64-bit targets DWARF-3+ is used DW_OP_GNU_implicit_pointer does not work.

DWARF-2 says:
	This type of reference (DW_FORM_ref_addr) is the size of an address on
	the target architecture; 
DWARF-3 says:
	1.5.1 Upward Compatibility
	References that use the attribute form DW_FORM_ref_addr are specified
	to be four bytes in the DWARF 32-bit format and eight bytes in the
	DWARF 64-bit format, while DWARF Version 2 specifies that such
	references have the same size as an address on the target system (see
	Sections 7.4 and 7.5.4).

	(DW_FORM_ref_addr)
	In the 32-bit DWARF format, this offset is a 4-byte unsigned value; in
	the 64-bit DWARF format, it is an 8-byte unsigned value (see Section
	7.4).

GDB currently parsed DW_OP_GNU_implicit_pointer the DWARF-2 way, being
incompatible with DWARF-3+.

I think DW_OP_GNU_implicit_pointer does not make sense to be used from
.debug_frame (DWARF-5 is not yet released to say more) so for .debug_frame its
use is just not permitted (the code would be more complicated otherwise).

No regressions on {x86_64,x86_64-m32,i686}-fedora16pre-linux-gnu.


Thanks,
Jan


gdb/
2011-09-26  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Fix DW_OP_GNU_implicit_pointer for DWARF32 v3+ on 64-bit arches.
	* dwarf2-frame.c (execute_stack_op): Initialize ctx->ref_addr_size.
	* dwarf2expr.c (execute_stack_op) <DW_OP_GNU_implicit_pointer>: Use
	ctx->ref_addr_size.  Handle its invalid value.
	* dwarf2expr.h (struct dwarf_expr_context): New field ref_addr_size.
	* dwarf2loc.c (dwarf2_evaluate_loc_desc_full)
	(dwarf2_loc_desc_needs_frame): Initialize ctx->ref_addr_size.
	* dwarf2loc.h (dwarf2_per_cu_ref_addr_size): New declaration.
	* dwarf2read.c (decode_locdesc): Initialize ctx->ref_addr_size.
	(dwarf2_per_cu_ref_addr_size): New function.

gdb/testsuite/
2011-09-26  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Fix DW_OP_GNU_implicit_pointer for DWARF32 v3+ on 64-bit arches.
	* gdb.dwarf2/implptr-64bit.S: New file.
	* gdb.dwarf2/implptr-64bit.exp: New file.

--- a/gdb/dwarf2-frame.c
+++ b/gdb/dwarf2-frame.c
@@ -371,6 +371,7 @@ execute_stack_op (const gdb_byte *exp, ULONGEST len, int addr_size,
 
   ctx->gdbarch = get_frame_arch (this_frame);
   ctx->addr_size = addr_size;
+  ctx->ref_addr_size = -1;
   ctx->offset = offset;
   ctx->baton = this_frame;
   ctx->funcs = &dwarf2_frame_ctx_funcs;
--- a/gdb/dwarf2expr.c
+++ b/gdb/dwarf2expr.c
@@ -709,10 +709,14 @@ execute_stack_op (struct dwarf_expr_context *ctx,
 	    ULONGEST die;
 	    LONGEST len;
 
+	    if (ctx->ref_addr_size == -1)
+	      error (_("DWARF-2 expression error: DW_OP_GNU_implicit_pointer "
+		       "is not allowed in frame context"));
+
 	    /* The referred-to DIE.  */
-	    ctx->len = extract_unsigned_integer (op_ptr, ctx->addr_size,
+	    ctx->len = extract_unsigned_integer (op_ptr, ctx->ref_addr_size,
 						 byte_order);
-	    op_ptr += ctx->addr_size;
+	    op_ptr += ctx->ref_addr_size;
 
 	    /* The byte offset into the data.  */
 	    op_ptr = read_sleb128 (op_ptr, op_end, &len);
--- a/gdb/dwarf2expr.h
+++ b/gdb/dwarf2expr.h
@@ -125,6 +125,10 @@ struct dwarf_expr_context
   /* Target address size in bytes.  */
   int addr_size;
 
+  /* DW_FORM_ref_addr size in bytes.  If -1 DWARF is executed from a frame
+     context and operations depending on DW_FORM_ref_addr are not allowed.  */
+  int ref_addr_size;
+
   /* Offset used to relocate DW_OP_addr argument.  */
   CORE_ADDR offset;
 
--- a/gdb/dwarf2loc.c
+++ b/gdb/dwarf2loc.c
@@ -1118,6 +1118,7 @@ dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame,
 
   ctx->gdbarch = get_objfile_arch (objfile);
   ctx->addr_size = dwarf2_per_cu_addr_size (per_cu);
+  ctx->ref_addr_size = dwarf2_per_cu_ref_addr_size (per_cu);
   ctx->offset = dwarf2_per_cu_text_offset (per_cu);
   ctx->baton = &baton;
   ctx->funcs = &dwarf_expr_ctx_funcs;
@@ -1398,6 +1399,7 @@ dwarf2_loc_desc_needs_frame (const gdb_byte *data, unsigned short size,
 
   ctx->gdbarch = get_objfile_arch (objfile);
   ctx->addr_size = dwarf2_per_cu_addr_size (per_cu);
+  ctx->ref_addr_size = dwarf2_per_cu_ref_addr_size (per_cu);
   ctx->offset = dwarf2_per_cu_text_offset (per_cu);
   ctx->baton = &baton;
   ctx->funcs = &needs_frame_ctx_funcs;
--- a/gdb/dwarf2loc.h
+++ b/gdb/dwarf2loc.h
@@ -39,6 +39,10 @@ struct objfile *dwarf2_per_cu_objfile (struct dwarf2_per_cu_data *cu);
 /* Return the address size given in the compilation unit header for CU.  */
 CORE_ADDR dwarf2_per_cu_addr_size (struct dwarf2_per_cu_data *cu);
 
+/* Return the DW_FORM_ref_addr size given in the compilation unit header for
+   CU.  */
+int dwarf2_per_cu_ref_addr_size (struct dwarf2_per_cu_data *cu);
+
 /* Return the offset size given in the compilation unit header for CU.  */
 int dwarf2_per_cu_offset_size (struct dwarf2_per_cu_data *cu);
 
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -15238,6 +15239,22 @@ dwarf2_per_cu_offset_size (struct dwarf2_per_cu_data *per_cu)
   return cu_headerp->offset_size;
 }
 
+/* See its dwarf2loc.h declaration.  */
+
+int
+dwarf2_per_cu_ref_addr_size (struct dwarf2_per_cu_data *per_cu)
+{
+  struct comp_unit_head cu_header_local;
+  const struct comp_unit_head *cu_headerp;
+
+  cu_headerp = per_cu_header_read_in (&cu_header_local, per_cu);
+
+  if (cu_headerp->version == 2)
+    return cu_headerp->addr_size;
+  else
+    return cu_headerp->offset_size;
+}
+
 /* Return the text offset of the CU.  The returned offset comes from
    this CU's objfile.  If this objfile came from a separate debuginfo
    file, then the offset may be different from the corresponding
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/implptr-64bit.S
@@ -0,0 +1,197 @@
+/* Copyright 2010, 2011 Free Software Foundation, Inc.
+
+   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 3 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, see <http://www.gnu.org/licenses/>.  */
+
+	.section	.debug_info
+d:
+	/* Length of Compilation Unit Info */
+#if OFFSET_SIZE == 4
+# define OFFSET .4byte
+	.4byte	debug_end - 1f
+#elif OFFSET_SIZE == 8
+# define OFFSET .8byte
+	.4byte	0xffffffff
+	.8byte	debug_end - 1f
+#else
+# error
+#endif
+#if ADDR_SIZE == 4
+# define ADDR .4byte
+#elif ADDR_SIZE == 8
+# define ADDR .8byte
+#else
+# error
+#endif
+#if REF_ADDR_SIZE == 4
+# define REF_ADDR .4byte
+#elif REF_ADDR_SIZE == 8
+# define REF_ADDR .8byte
+#else
+# error
+#endif
+1:
+	.2byte	DWARF_VERSION	/* DWARF version number */
+	OFFSET	.Ldebug_abbrev0	/* Offset Into Abbrev. Section */
+	.byte	ADDR_SIZE	/* Pointer Size (in bytes) */
+
+	.uleb128 0x1	/* (DIE (0xb) DW_TAG_compile_unit) */
+	.ascii "GNU C 4.4.3\0"	/* DW_AT_producer */
+	.byte	0x1	/* DW_AT_language */
+	.ascii "1.c\0"	/* DW_AT_name */
+
+.Ltype_int:
+	.uleb128 0x7	/* DW_TAG_base_type */
+	.byte	0x4	/* DW_AT_byte_size */
+	.byte	0x5	/* DW_AT_encoding */
+	.ascii "int\0"	/* DW_AT_name */
+
+.Ltype_struct:
+	.uleb128 0x2	/* DW_TAG_structure_type */
+	.ascii "s\0"	/* DW_AT_name */
+	.byte	4	/* DW_AT_byte_size */
+
+	.uleb128 0x3	/* DW_TAG_member */
+	.ascii "f\0"	/* DW_AT_name */
+	.4byte	.Ltype_int - d	/* DW_AT_type */
+	.byte	0	/* DW_AT_data_member_location */
+
+	.byte	0x0	/* end of children of DW_TAG_structure_type */
+
+	.uleb128	6			/* Abbrev: DW_TAG_subprogram */
+	.ascii		"main\0"		/* DW_AT_name */
+	ADDR		main			/* DW_AT_low_pc */
+	ADDR		main + 0x100		/* DW_AT_high_pc */
+	.4byte		.Ltype_int - d		/* DW_AT_type */
+	.byte		1			/* DW_AT_external */
+
+.Ltype_structptr:
+	.uleb128 0x5	/* DW_TAG_pointer_type */
+	.byte	ADDR_SIZE	/* DW_AT_byte_size */
+	.4byte	.Ltype_struct - d	/* DW_AT_type */
+
+.Lvar_out:
+	.uleb128 0x4	/* (DW_TAG_variable) */
+	.ascii "v\0"	/* DW_AT_name */
+	.byte	2f - 1f	/* DW_AT_location: DW_FORM_block1 */
+1:
+	.byte	0x9e	/* DW_OP_implicit_value */
+	.uleb128  2f - 3f
+3:
+	.byte	1, 1, 1, 1
+2:
+	.4byte	.Ltype_struct - d	/* DW_AT_type */
+
+	.uleb128 0x4	/* (DW_TAG_variable) */
+	.ascii "p\0"	/* DW_AT_name */
+	.byte	2f - 1f	/* DW_AT_location: DW_FORM_block1 */
+1:
+	.byte	0xf2	/* DW_OP_GNU_implicit_pointer */
+	REF_ADDR	.Lvar_out - d	/* referenced DIE */
+	.sleb128	0	/* offset */
+2:
+	.4byte	.Ltype_structptr - d	/* DW_AT_type */
+
+	.byte	0x0	/* end of children of main */
+
+	.byte	0x0	/* end of children of CU */
+debug_end:
+
+	.section	.debug_abbrev
+.Ldebug_abbrev0:
+
+	.uleb128 0x1	/* (abbrev code) */
+	.uleb128 0x11	/* (TAG: DW_TAG_compile_unit) */
+	.byte	0x1	/* DW_children_yes */
+	.uleb128 0x25	/* (DW_AT_producer) */
+	.uleb128 0x8	/* (DW_FORM_string) */
+	.uleb128 0x13	/* (DW_AT_language) */
+	.uleb128 0xb	/* (DW_FORM_data1) */
+	.uleb128 0x3	/* (DW_AT_name) */
+	.uleb128 0x8	/* (DW_FORM_string) */
+	.byte	0x0
+	.byte	0x0
+
+	.uleb128 0x2	/* (abbrev code) */
+	.uleb128 0x13	/* (TAG: DW_TAG_structure_type) */
+	.byte	0x1	/* DW_children_yes */
+	.uleb128 0x3	/* (DW_AT_name) */
+	.uleb128 0x8	/* (DW_FORM_string) */
+	.uleb128 0xb	/* (DW_AT_byte_size) */
+	.uleb128 0xb	/* (DW_FORM_data1) */
+	.byte	0
+	.byte	0
+
+	.uleb128 0x3	/* (abbrev code) */
+	.uleb128 0xd	/* (TAG: DW_TAG_member) */
+	.byte	0	/* DW_children_no */
+	.uleb128 0x3	/* (DW_AT_name) */
+	.uleb128 0x8	/* (DW_FORM_string) */
+	.uleb128 0x49	/* (DW_AT_type) */
+	.uleb128 0x13	/* (DW_FORM_ref4) */
+	.uleb128 0x38	/* (DW_AT_data_member_location) */
+	.uleb128 0xb	/* (DW_FORM_data1) */
+	.byte	0
+	.byte	0
+
+	.uleb128 0x4	/* (abbrev code) */
+	.uleb128 0x34	/* (TAG: DW_TAG_variable) */
+	.byte	0x0	/* DW_children_yes */
+	.uleb128 0x3	/* (DW_AT_name) */
+	.uleb128 0x8	/* (DW_FORM_string) */
+	.uleb128 0x02	/* (DW_AT_location) */
+	.uleb128 0xa	/* (DW_FORM_block1) */
+	.uleb128 0x49	/* (DW_AT_type) */
+	.uleb128 0x13	/* (DW_FORM_ref4) */
+	.byte	0x0
+	.byte	0x0
+
+	.uleb128 0x5	/* (abbrev code) */
+	.uleb128 0xf	/* (TAG: DW_TAG_pointer_type) */
+	.byte	0x0	/* DW_children_no */
+	.uleb128 0xb	/* (DW_AT_byte_size) */
+	.uleb128 0xb	/* (DW_FORM_data1) */
+	.uleb128 0x49	/* (DW_AT_type) */
+	.uleb128 0x13	/* (DW_FORM_ref4) */
+	.byte	0x0
+	.byte	0x0
+
+	.uleb128	6			/* Abbrev code */
+	.uleb128	0x2e			/* DW_TAG_subprogram */
+	.byte		1			/* has_children */
+	.uleb128	0x3			/* DW_AT_name */
+	.uleb128	0x8			/* DW_FORM_string */
+	.uleb128	0x11			/* DW_AT_low_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x12			/* DW_AT_high_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x49			/* DW_AT_type */
+	.uleb128	0x13			/* DW_FORM_ref4 */
+	.uleb128	0x3f			/* DW_AT_external */
+	.uleb128	0xc			/* DW_FORM_flag */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.uleb128 0x7	/* (abbrev code) */
+	.uleb128 0x24	/* (TAG: DW_TAG_base_type) */
+	.byte	0	/* DW_children_no */
+	.uleb128 0xb	/* (DW_AT_byte_size) */
+	.uleb128 0xb	/* (DW_FORM_data1) */
+	.uleb128 0x3e	/* (DW_AT_encoding) */
+	.uleb128 0xb	/* (DW_FORM_data1) */
+	.uleb128 0x3	/* (DW_AT_name) */
+	.uleb128 0x8	/* (DW_FORM_string) */
+	.byte	0
+	.byte	0
+
+	.byte	0x0
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/implptr-64bit.exp
@@ -0,0 +1,51 @@
+# Copyright 2011 Free Software Foundation, Inc.
+
+# 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 3 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, see <http://www.gnu.org/licenses/>.
+load_lib dwarf.exp
+
+# This test can only be run on targets which support DWARF-2 and use gas.
+if {![dwarf2_support]} {
+    return 0  
+}
+
+set testfile "implptr-64bit"
+set srcfile ${testfile}.S
+set mainfile main.c
+
+proc test { dwarf_version offset_size addr_size ref_addr_size } {
+    global testfile srcfile mainfile
+
+    set opts {}
+    foreach n { dwarf_version offset_size addr_size ref_addr_size } {
+	lappend opts "additional_flags=-D[string toupper $n]=[expr "\$$n"]"
+    }
+
+    set name "d${dwarf_version}o${offset_size}a${addr_size}r${ref_addr_size}"
+    set executable ${testfile}-${name}
+    if [prepare_for_testing ${testfile}.exp $executable "${srcfile} ${mainfile}" $opts] {
+	return -1
+    }
+
+    if ![runto_main] {
+	return -1
+    }
+
+    gdb_test "p/x p->f" " = 0x1010101" $name
+}
+
+#    DWARF_VERSION OFFSET_SIZE ADDR_SIZE REF_ADDR_SIZE
+test 2 8 4 4
+test 2 4 8 8
+test 3 8 4 8
+test 3 4 8 4