Re: [V4 00/21] Fortran dynamic array support

[Jan Kratochvil <jan.kratochvil@redhat.com>]

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On Fri, 02 Sep 2016 15:44:15 +0200, Bernhard Heckel wrote:
> dynamic properties in GDB is done via CORE_ADDR which is unsigned.
> This causes the issue that the type length seems to be way to big.

Maybe that explains also a regression visible only on i686 (32-bit host).
It still PASSes on x86_64 (64-bit host) with either native od 32-bit inferior
(-m32):

The length is bogus (it is %rax or %eax) but it should be some number.

i686:
ptype reg_string^M
type = char [variable length]^M
             ^^^^^^^^^^^^^^^
(gdb) FAIL: gdb.dwarf2/dw2-bound-loclist.exp: ptype reg_string
p reg_string^M
Insufficient memory in host GDB for object of size 4160138653 bytes, maximum allowed 536870911 bytes.^M

x86_64 or x86_64 -m32:
ptype reg_string^M
type = char [4160048541]^M
(gdb) PASS: gdb.dwarf2/dw2-bound-loclist.exp: ptype reg_string

Attaching the Fedora testcase.


Thanks,
Jan

[-- Attachment #2: dw2-bound-loclist.patch --]
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--- /dev/null	2016-08-23 22:46:08.455975850 +0200
+++ gdb-7.11.90.20160904/gdb/testsuite/gdb.dwarf2/dw2-bound-loclist.exp	2016-09-04 19:09:23.719880045 +0200
@@ -0,0 +1,66 @@
+# Copyright 2010 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/>.
+
+# Test printing variable with dynamic bounds which reference a different
+# (artificial in the GCC case) variable containing loclist as its location.
+# This testcase uses value (not address) of the referenced variable:
+# http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43762
+
+# This test can only be run on targets which support DWARF-2 and use gas.
+# For now pick a sampling of likely targets.
+if {![istarget *-*-linux*]
+    && ![istarget *-*-gnu*]
+    && ![istarget *-*-elf*]
+    && ![istarget *-*-openbsd*]
+    && ![istarget arm-*-eabi*]
+    && ![istarget powerpc-*-eabi*]} {
+    return 0
+}
+
+set testfile dw2-bound-loclist
+if { [prepare_for_testing ${testfile}.exp ${testfile} [list ${testfile}.S main.c] {}] } {
+    return -1
+}
+
+# Verify it behaves at least as an unbound array without inferior.
+
+# FIXME: FSF GDB crashes due to !has_stack_frames ().
+# But in practice that should not happen.
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43762
+#set test "p a_string"
+#gdb_test_multiple $test $test {
+#    -re " = 0x\[0-9a-f\]+ \"seennotseen\"\r\n$gdb_prompt $" {
+#	pass $test
+#    }
+#    -re "No registers\\.\r\n$gdb_prompt $" {
+#	kfail "vlaregression" $test
+#    }
+#}
+#
+#gdb_test "ptype a_string" {type = char \[variable length\]}
+
+# Not runto_main as dw2-bound-loclist.S handles only the first byte of main.
+if ![runto "*main"] {
+    return -1
+}
+
+gdb_test "p a_string" { = "seen"}
+gdb_test "ptype a_string" {type = char \[4\]}
+
+gdb_test "p b_string" { = (0x[0-9a-f]+ )?"seennotseen"}
+gdb_test "ptype b_string" {type = char \[\]}
+
+# The register contains unpredictable value - the array size.
+gdb_test "ptype reg_string" {type = char \[-?[0-9]+\]}
--- /dev/null	2016-08-23 22:46:08.455975850 +0200
+++ gdb-7.11.90.20160904/gdb/testsuite/gdb.dwarf2/dw2-bound-loclist.S	2016-09-04 19:09:23.719880045 +0200
@@ -0,0 +1,246 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2010 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/>.  */
+
+/* Debug information */
+
+/* We will `break *main' at the very first instruction.  */
+#define main_length 1
+
+	.section	.data
+vardata:
+	/* See DW_OP_lit3 + 1 (0-based).  */
+	.string		"seennotseen"
+
+	.section	.debug_info
+.Lcu1_begin:
+	.4byte		.Lcu1_end - .Lcu1_start	/* Length of Compilation Unit */
+.Lcu1_start:
+	.2byte		2			/* DWARF version number */
+	.4byte		.Ldebug_abbrev0		/* Offset Into Abbrev. Section */
+	.byte		4			/* Pointer Size (in bytes) */
+
+	/* CU die */
+	.uleb128	1			/* Abbrev: DW_TAG_compile_unit */
+	.4byte		.Lproducer		/* DW_AT_producer */
+	/* Use C++ to exploit a bug in parsing DW_AT_name "".  */
+	.byte		4			/* DW_AT_language (C++) -  */
+	.4byte		main			/* DW_AT_low_pc */
+	.byte		main_length		/* DW_AT_high_pc */
+
+.Larray_type:
+	.uleb128	2			/* Abbrev: DW_TAG_array_type */
+	.4byte		.Lchar_type-.Lcu1_begin	/* DW_AT_type */
+
+	.uleb128	3			/* Abbrev: DW_TAG_subrange_type */
+	.4byte		.Luint_type-.Lcu1_begin	/* DW_AT_type */
+	.byte		0			/* DW_AT_lower_bound */
+	.4byte		.Llen_var-.Lcu1_begin	/* DW_AT_upper_bound */
+	.byte		0			/* End of children of die */
+
+	/* DW_AT_upper_bound is referencing an optimized-out variable.  */
+.Larrayb_type:
+	.uleb128	2			/* Abbrev: DW_TAG_array_type */
+	.4byte		.Lchar_type-.Lcu1_begin	/* DW_AT_type */
+
+	.uleb128	3			/* Abbrev: DW_TAG_subrange_type */
+	.4byte		.Luint_type-.Lcu1_begin	/* DW_AT_type */
+	.byte		0			/* DW_AT_lower_bound */
+	.4byte		.Llenb_var-.Lcu1_begin	/* DW_AT_upper_bound */
+	.byte		0			/* End of children of die */
+
+	/* DW_AT_upper_bound is referencing register.  */
+.Larrayreg_type:
+	.uleb128	2			/* Abbrev: DW_TAG_array_type */
+	.4byte		.Lchar_type-.Lcu1_begin	/* DW_AT_type */
+
+	.uleb128	8			/* Abbrev: DW_TAG_subrange_type with block */
+	.4byte		.Luint_type-.Lcu1_begin	/* DW_AT_type */
+	.byte		0			/* DW_AT_lower_bound */
+	.byte		2f - 1f			/* DW_AT_upper_bound */
+1:	.byte		0x50			/* DW_OP_reg0 */
+2:
+	.byte		0			/* End of children of die */
+
+.Luint_type:
+	.uleb128	4			/* Abbrev: DW_TAG_base_type */
+	.4byte		.Luint_str		/* DW_AT_name */
+	.byte		4			/* DW_AT_byte_size */
+	.byte		7			/* DW_AT_encoding */
+
+.Lchar_type:
+	.uleb128	4			/* Abbrev: DW_TAG_base_type */
+	.4byte		.Lchar_str		/* DW_AT_name */
+	.byte		1			/* DW_AT_byte_size */
+	.byte		6			/* DW_AT_encoding */
+
+.Llen_var:
+	.uleb128	5			/* Abbrev: DW_TAG_variable artificial */
+	.byte		1			/* DW_AT_artificial */
+	.4byte		.Luint_type-.Lcu1_begin	/* DW_AT_type */
+	.4byte		.Llen_loclist-.Lloclist	/* DW_AT_location */
+
+	/* optimized-out variable for b_string.  */
+.Llenb_var:
+	.uleb128	7			/* Abbrev: DW_TAG_variable artificial no DW_AT_location */
+	.byte		1			/* DW_AT_artificial */
+	.4byte		.Luint_type-.Lcu1_begin	/* DW_AT_type */
+
+	.uleb128	6			/* Abbrev: DW_TAG_variable DW_FORM_string */
+	.string		"a_string"		/* DW_AT_name */
+	.4byte		.Larray_type-.Lcu1_begin /* DW_AT_type */
+	.byte		2f - 1f			/* DW_AT_location */
+1:	.byte		3			/*   DW_OP_addr */
+	.4byte		vardata			/*   <addr> */
+2:
+
+	/* DW_AT_upper_bound is referencing an optimized-out variable.  */
+	.uleb128	6			/* Abbrev: DW_TAG_variable DW_FORM_string */
+	.string		"b_string"		/* DW_AT_name */
+	.4byte		.Larrayb_type-.Lcu1_begin /* DW_AT_type */
+	.byte		2f - 1f			/* DW_AT_location */
+1:	.byte		3			/*   DW_OP_addr */
+	.4byte		vardata			/*   <addr> */
+2:
+
+	/* DW_AT_upper_bound is referencing register.  */
+	.uleb128	6			/* Abbrev: DW_TAG_variable DW_FORM_string */
+	.string		"reg_string"		/* DW_AT_name */
+	.4byte		.Larrayreg_type-.Lcu1_begin /* DW_AT_type */
+	.byte		2f - 1f			/* DW_AT_location */
+1:	.byte		3			/*   DW_OP_addr */
+	.4byte		vardata			/*   <addr> */
+2:
+
+	.byte		0			/* End of children of CU */
+.Lcu1_end:
+
+	.section	.debug_loc
+.Lloclist:
+.Llen_loclist:
+	.4byte	0			# Location list begin address
+	.4byte	main_length		# Location list end address
+	.value	2f-1f	# Location expression size
+1:	.byte	0x33	# DW_OP_lit3
+	.byte	0x9f	# DW_OP_stack_value
+2:
+	.quad	0x0	# Location list terminator begin (*.LLST2)
+	.quad	0x0	# Location list terminator end (*.LLST2)
+
+	.section .debug_abbrev
+.Ldebug_abbrev0:
+	.uleb128	1			/* Abbrev code */
+	.uleb128	0x11			/* DW_TAG_compile_unit */
+	.byte		0x1			/* has_children */
+	.uleb128	0x25			/* DW_AT_producer */
+	.uleb128	0xe			/* DW_FORM_strp */
+	.uleb128	0x13			/* DW_AT_language */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x11			/* DW_AT_low_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x12			/* DW_AT_high_pc */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.uleb128	2			/* Abbrev code */
+	.uleb128	0x1			/* TAG: DW_TAG_array_type */
+	.byte		0x1			/* DW_children_yes */
+	.uleb128	0x49			/* DW_AT_type */
+	.uleb128	0x13			/* DW_FORM_ref4 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.uleb128	3			/* Abbrev code */
+	.uleb128	0x21			/* DW_TAG_subrange_type */
+	.byte		0x0			/* no children */
+	.uleb128	0x49			/* DW_AT_type */
+	.uleb128	0x13			/* DW_FORM_ref4 */
+	.uleb128	0x22			/* DW_AT_lower_bound */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x2f			/* DW_AT_upper_bound */
+	.uleb128	0x13			/* DW_FORM_ref4 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.uleb128	4			/* Abbrev code */
+	.uleb128	0x24			/* DW_TAG_base_type */
+	.byte		0x0			/* no_children */
+	.uleb128	0x3			/* DW_AT_name */
+	.uleb128	0xe			/* DW_FORM_strp */
+	.uleb128	0xb			/* DW_AT_byte_size */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x3e			/* DW_AT_encoding */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.uleb128	5			/* Abbrev code */
+	.uleb128	0x34			/* DW_TAG_variable */
+	.byte		0x0			/* no_children */
+	.uleb128	0x34			/* DW_AT_artificial */
+	.uleb128	0x0c			/* DW_FORM_flag */
+	.uleb128	0x49			/* DW_AT_type */
+	.uleb128	0x13			/* DW_FORM_ref4 */
+	.uleb128	0x02			/* DW_AT_location */
+	.uleb128	0x06			/* DW_FORM_data4 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.uleb128	6			/* Abbrev code */
+	.uleb128	0x34			/* DW_TAG_variable */
+	.byte		0x0			/* no_children */
+	.uleb128	0x3			/* DW_AT_name */
+	.uleb128	0x8			/* DW_FORM_string */
+	.uleb128	0x49			/* DW_AT_type */
+	.uleb128	0x13			/* DW_FORM_ref4 */
+	.uleb128	0x2			/* DW_AT_location */
+	.uleb128	0xa			/* DW_FORM_block1 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.uleb128	7			/* Abbrev code */
+	.uleb128	0x34			/* DW_TAG_variable */
+	.byte		0x0			/* no_children */
+	.uleb128	0x34			/* DW_AT_artificial */
+	.uleb128	0x0c			/* DW_FORM_flag */
+	.uleb128	0x49			/* DW_AT_type */
+	.uleb128	0x13			/* DW_FORM_ref4 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.uleb128	8			/* Abbrev code */
+	.uleb128	0x21			/* DW_TAG_subrange_type with block */
+	.byte		0x0			/* no children */
+	.uleb128	0x49			/* DW_AT_type */
+	.uleb128	0x13			/* DW_FORM_ref4 */
+	.uleb128	0x22			/* DW_AT_lower_bound */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x2f			/* DW_AT_upper_bound */
+	.uleb128	0xa			/* DW_FORM_block1 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.byte		0x0			/* Terminator */
+
+/* String table */
+	.section .debug_str
+.Lproducer:
+	.string		"GNU C 3.3.3"
+.Lchar_str:
+	.string		"char"
+.Luint_str:
+	.string		"unsigned int"