From 433730c97306608f78fc8de0a319c9a5c6758db2 Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Fri, 19 Apr 2013 14:13:30 +0000 Subject: =?UTF-8?q?Fix=20the=20x87=20FP=20register=20printout=20when=20iss?= =?UTF-8?q?uing=20the=20=E2=80=9Cinfo=20float=E2=80=9D=20command.?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Consider the following simple program: .globl _start .text _start: fldt val .data val: .byte 0x00,0x00,0x45,0x07,0x11,0x19,0x22,0xe9,0xfe,0xbf With current GDB on x86-64 GNU/Linux hosts, after the moment the fldt command has been executed the register st(0) looks like this, according to the “info regs” output (TOP=7): R7: Valid 0xffffffbffffffffeffffffe922191107450000 -0.910676542908976927 which is clearly wrong (just count its length). The problem is due to the printf statement (see patch) printing a promoted integer value of a char argument "raw[i]", and, since char is signed on x86-64 GNU/Linux, the erroneous “ffffff” are printed for the first three bytes which turn out to be "negative". The fix is to use gdb_byte instead which is unsigned (and is the type of value_contents(), the type to be used for raw target bytes anyway). After the fix the value will be printed correctly: R7: Valid 0xbffee922191107450000 -0.910676542908976927 gdb/ 2013-04-19 Vladimir Kargov Pedro Alves * i387-tdep.c (i387_print_float_info): Use gdb_byte for pointer to value contents. gdb/testsuite/ 2013-04-19 Vladimir Kargov Pedro Alves * gdb.arch/i386-float.S: New file. * gdb.arch/i386-float.exp: New file. --- gdb/ChangeLog | 6 +++++ gdb/i387-tdep.c | 2 +- gdb/testsuite/ChangeLog | 6 +++++ gdb/testsuite/gdb.arch/i386-float.S | 34 +++++++++++++++++++++++++++ gdb/testsuite/gdb.arch/i386-float.exp | 43 +++++++++++++++++++++++++++++++++++ 5 files changed, 90 insertions(+), 1 deletion(-) create mode 100644 gdb/testsuite/gdb.arch/i386-float.S create mode 100644 gdb/testsuite/gdb.arch/i386-float.exp diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 85c3245..80fb6de 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2013-04-19 Vladimir Kargov + Pedro Alves + + * i387-tdep.c (i387_print_float_info): Use gdb_byte for pointer to + value contents. + 2013-04-17 Doug Evans * dwarf2read.c (struct signatured_type): New member type. diff --git a/gdb/i387-tdep.c b/gdb/i387-tdep.c index 65bb103..48a00c3 100644 --- a/gdb/i387-tdep.c +++ b/gdb/i387-tdep.c @@ -298,7 +298,7 @@ i387_print_float_info (struct gdbarch *gdbarch, struct ui_file *file, if (value_entirely_available (regval)) { - const char *raw = value_contents (regval); + const gdb_byte *raw = value_contents (regval); fputs_filtered ("0x", file); for (i = 9; i >= 0; i--) diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 4d69f41..d262b81 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2013-04-19 Vladimir Kargov + Pedro Alves + + * gdb.arch/i386-float.S: New file. + * gdb.arch/i386-float.exp: New file. + 2013-04-18 Luis Machado * gdb.mi/mi-var-create-rtti.exp: Create a variable of diff --git a/gdb/testsuite/gdb.arch/i386-float.S b/gdb/testsuite/gdb.arch/i386-float.S new file mode 100644 index 0000000..c4f6391 --- /dev/null +++ b/gdb/testsuite/gdb.arch/i386-float.S @@ -0,0 +1,34 @@ +/* Copyright 2009-2013 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 . + + This file is part of the gdb testsuite. */ + +#define CONCAT1(a, b) CONCAT2(a, b) +#define CONCAT2(a, b) a ## b + +#ifdef SYMBOL_PREFIX +# define SYMBOL(str) CONCAT1(SYMBOL_PREFIX, str) +#else +# define SYMBOL(str) str +#endif + + .text + .globl SYMBOL(main) +SYMBOL(main): + fninit + fldt val + ret +.data + val: .byte 0x00,0x00,0x45,0x07,0x11,0x19,0x22,0xe9,0xfe,0xbf diff --git a/gdb/testsuite/gdb.arch/i386-float.exp b/gdb/testsuite/gdb.arch/i386-float.exp new file mode 100644 index 0000000..c417532 --- /dev/null +++ b/gdb/testsuite/gdb.arch/i386-float.exp @@ -0,0 +1,43 @@ +# Copyright (C) 2009-2013 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 . + + +# This file is part of the gdb testsuite. + +# Test the x87 floating point information printout. + +if { ![istarget "i?86-*-*"] && ![istarget "x86_64-*-*"] } then { + verbose "Skipping i386 tests for x87 floating point support." + return +} + +standard_testfile .S + +# some targets have leading underscores on assembly symbols. +set additional_flags [gdb_target_symbol_prefix_flags] + +if { [prepare_for_testing break.exp $testfile $srcfile [list debug $additional_flags]] } { + return -1 +} + +if ![runto_main] then { + fail "Can't run to main" + return 0 +} + +gdb_test "stepi" ".*fldt.*" "first stepi" +gdb_test "info float" ".*R7: Empty 0x00000000000000000000\r\n.*" +gdb_test "stepi" ".*ret.*" "second stepi" +gdb_test "info float" ".*=>R7: Valid 0xbffee922191107450000 .*" -- cgit v1.1