From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 11688 invoked by alias); 14 May 2013 13:50:20 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 11677 invoked by uid 89); 14 May 2013 13:50:20 -0000 X-Spam-SWARE-Status: No, score=-6.6 required=5.0 tests=AWL,BAYES_00,RCVD_IN_HOSTKARMA_W,RCVD_IN_HOSTKARMA_WL,RP_MATCHES_RCVD,SPF_HELO_PASS,SPF_PASS autolearn=ham version=3.3.1 Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.84/v0.84-167-ge50287c) with ESMTP; Tue, 14 May 2013 13:50:18 +0000 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r4EDoFof027202 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 14 May 2013 09:50:16 -0400 Received: from barimba (ovpn-113-133.phx2.redhat.com [10.3.113.133]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r4EDoBNI032289 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Tue, 14 May 2013 09:50:14 -0400 From: Tom Tromey To: gdb-patches@sourceware.org Subject: [RFC, v2] Fix PR symtab/15391 Date: Tue, 14 May 2013 13:50:00 -0000 Message-ID: <87hai57jsc.fsf@fleche.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-SW-Source: 2013-05/txt/msg00466.txt.bz2 Jan's note about -m32 testing for implptrconst.exp made me revisit this patch. The new version fixes some more bugs. PR symtab/15391 is a failure with the DW_OP_GNU_implicit_pointer feature. I tracked it down to a logic error in read_pieced_value. The code truncates this_size_bits according to the type size and offset too early -- it should do it after taking bits_to_skip into account. This patch fixes the bug. While testing this, I also tripped across a latent bug because indirect_pieced_value does not sign-extend where needed. This patch fixes this bug as well. Built and regtested on x86-64 Fedora 18. New test cases included; this required a minor addition to the DWARF assembler. Note that the DWARF CU made by implptrpiece.exp uses a funny pointer size in order to show the sign-extension bug on all platforms. * dwarf2loc.c (read_pieced_value): Truncate this_size_bits after taking bits_to_skip into account. Sign extend byte_offset. * gdb.dwarf2/implptrpiece.exp: New file. * gdb.dwarf2/implptrconst.exp (d): New variable. Print d. * lib/dwarf2.exp (Dwarf::_location): Handle DW_OP_piece. --- gdb/dwarf2loc.c | 20 ++++- gdb/testsuite/gdb.dwarf2/implptrconst.exp | 9 ++ gdb/testsuite/gdb.dwarf2/implptrpiece.exp | 131 ++++++++++++++++++++++++++++++ gdb/testsuite/lib/dwarf.exp | 4 + 4 files changed, 160 insertions(+), 4 deletions(-) create mode 100644 gdb/testsuite/gdb.dwarf2/implptrpiece.exp diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c index 9e44096..7beb927 100644 --- a/gdb/dwarf2loc.c +++ b/gdb/dwarf2loc.c @@ -1641,8 +1641,6 @@ read_pieced_value (struct value *v) bits_to_skip -= this_size_bits; continue; } - if (this_size_bits > type_len - offset) - this_size_bits = type_len - offset; if (bits_to_skip > 0) { dest_offset_bits = 0; @@ -1655,6 +1653,8 @@ read_pieced_value (struct value *v) dest_offset_bits = offset; source_offset_bits = 0; } + if (this_size_bits > type_len - offset) + this_size_bits = type_len - offset; this_size = (this_size_bits + source_offset_bits % 8 + 7) / 8; source_offset = source_offset_bits / 8; @@ -2087,8 +2087,20 @@ indirect_pieced_value (struct value *value) frame = get_selected_frame (_("No frame selected.")); - /* This is an offset requested by GDB, such as value subcripts. */ + /* This is an offset requested by GDB, such as value subscripts. + However, due to how synthetic pointers are implemented, this is + always presented to us as a pointer type. This means we have to + sign-extend it manually as appropriate. */ byte_offset = value_as_address (value); + if (TYPE_LENGTH (value_type (value)) < sizeof (LONGEST)) + { + LONGEST nbits = 8 * TYPE_LENGTH (value_type (value)); + LONGEST m1 = -1; + + if (((byte_offset >> (nbits - 1)) & 1) != 0) + byte_offset |= m1 << nbits; + } + byte_offset += piece->v.ptr.offset; gdb_assert (piece); baton @@ -2099,7 +2111,7 @@ indirect_pieced_value (struct value *value) if (baton.data != NULL) return dwarf2_evaluate_loc_desc_full (TYPE_TARGET_TYPE (type), frame, baton.data, baton.size, baton.per_cu, - piece->v.ptr.offset + byte_offset); + byte_offset); { struct obstack temp_obstack; diff --git a/gdb/testsuite/gdb.dwarf2/implptrconst.exp b/gdb/testsuite/gdb.dwarf2/implptrconst.exp index 7eca600..566ac01 100644 --- a/gdb/testsuite/gdb.dwarf2/implptrconst.exp +++ b/gdb/testsuite/gdb.dwarf2/implptrconst.exp @@ -73,6 +73,14 @@ Dwarf::assemble $asm_file { GNU_implicit_pointer $var_label 0 } SPECIAL_expr} } + + DW_TAG_variable { + {name d} + {type :$ptr_label} + {location { + GNU_implicit_pointer $var_label 2 + } SPECIAL_expr} + } } } } @@ -103,3 +111,4 @@ if ![runto_main] { } gdb_test "print *c" " = 114 'r'" +gdb_test "print d\[-2\]" " = 114 'r'" diff --git a/gdb/testsuite/gdb.dwarf2/implptrpiece.exp b/gdb/testsuite/gdb.dwarf2/implptrpiece.exp new file mode 100644 index 0000000..a8d4e8e --- /dev/null +++ b/gdb/testsuite/gdb.dwarf2/implptrpiece.exp @@ -0,0 +1,131 @@ +# Copyright 2013 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 . + +load_lib dwarf.exp + +# This test can only be run on targets which support DWARF-2 and use gas. +if {![dwarf2_support]} { + return 0 +} + +if { [skip_cplus_tests] } { continue } + +standard_testfile main.c implptrpiece-dw.S + +# Make some DWARF for the test. +set asm_file [standard_output_file $srcfile2] + +Dwarf::assemble $asm_file { + # Using a funny address size here and in the pointer type lets us + # also check for a sign-extension bug in the + # DW_OP_GNU_implicit_pointer code. + cu 0 2 2 { + compile_unit {} { + declare_labels struct_label short_type_label + declare_labels char_type_label ptr_label + declare_labels var_label + + struct_label: structure_type { + {name S} + {byte_size 4 DW_FORM_sdata} + } { + member { + {name a} + {type :$short_type_label} + {data_member_location 0 DW_FORM_sdata} + } + member { + {name b} + {type :$char_type_label} + {data_member_location 2 DW_FORM_sdata} + } + member { + {name c} + {type :$char_type_label} + {data_member_location 3 DW_FORM_sdata} + } + } + + short_type_label: base_type { + {name "short int"} + {encoding @DW_ATE_signed} + {byte_size 2 DW_FORM_sdata} + } + + char_type_label: base_type { + {name "signed char"} + {encoding @DW_ATE_signed} + {byte_size 1 DW_FORM_sdata} + } + + # See comment above to understand the pointer size. + ptr_label: pointer_type { + {byte_size 2 DW_FORM_sdata} + {type :$char_type_label} + } + + var_label: DW_TAG_variable { + {name s} + {type :$struct_label} + {location { + const1u 1 + stack_value + piece 2 + const1u 2 + stack_value + piece 1 + const1u 3 + stack_value + piece 1 + } SPECIAL_expr} + } + + DW_TAG_variable { + {name p} + {type :$ptr_label} + {location { + GNU_implicit_pointer $var_label 2 + } SPECIAL_expr} + } + } + } +} + +if {[gdb_compile ${srcdir}/${subdir}/${srcfile} ${binfile}1.o \ + object {nodebug}] != ""} { + return -1 +} + +if {[gdb_compile $asm_file ${binfile}2.o object {nodebug}] != ""} { + return -1 +} + +if {[gdb_compile [list ${binfile}1.o ${binfile}2.o] \ + "${binfile}" executable {}] != ""} { + return -1 +} + +# We need --readnow because otherwise we never read in the CU we +# created above. +set saved_gdbflags $GDBFLAGS +set GDBFLAGS "$GDBFLAGS -readnow" +clean_restart ${testfile} +set GDBFLAGS $saved_gdbflags + +if ![runto_main] { + return -1 +} + +gdb_test "print/d p\[-1\]" " = 0" diff --git a/gdb/testsuite/lib/dwarf.exp b/gdb/testsuite/lib/dwarf.exp index 2e5a3f7..b73784f 100644 --- a/gdb/testsuite/lib/dwarf.exp +++ b/gdb/testsuite/lib/dwarf.exp @@ -646,6 +646,10 @@ namespace eval Dwarf { _op .sleb128 [lindex $line 1] } + DW_OP_piece { + _op .uleb128 [lindex $line 1] + } + DW_OP_GNU_implicit_pointer { if {[llength $line] != 3} { error "usage: DW_OP_GNU_implicit_pointer LABEL OFFSET" -- 1.8.1.4