From 3256027470cc5339e32600cd0d5900f3ce3344e7 Mon Sep 17 00:00:00 2001 From: Joel Brobecker Date: Wed, 24 Oct 2012 18:11:21 +0000 Subject: [PATCH] off-by-one max exponent computation in convert_doublest_to_floatformat Assuming the following variable definition: long double inp = 2.0; On platforms where "long double" is a double precision IEEE flaoting point, GDB currently behaves as follow: (gdb) set variable inp = 1.6e+308l (gdb) p inp $2 = inf <<<<---- !!!! Instead, the value of "inp" should be printed as: (gdb) p inp $1 = 1.6e+308 The problem is due to a small error in the comparison of the exponent versus the maximum value this exponent can take, causing us to think that the value was too big to fit. But it isn't. gdb/ChangeLog: * doublest.c (convert_doublest_to_floatformat): Fix comparison against maximum exponent value. gdb/testsuite/ChangeLog: * gdb.base/ldbl_e308.c, gdb.base/ldbl_e308.exp: New files. --- gdb/ChangeLog | 5 +++++ gdb/doublest.c | 2 +- gdb/testsuite/ChangeLog | 4 ++++ gdb/testsuite/gdb.base/ldbl_e308.c | 26 +++++++++++++++++++++++ gdb/testsuite/gdb.base/ldbl_e308.exp | 31 ++++++++++++++++++++++++++++ 5 files changed, 67 insertions(+), 1 deletion(-) create mode 100644 gdb/testsuite/gdb.base/ldbl_e308.c create mode 100644 gdb/testsuite/gdb.base/ldbl_e308.exp diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 4d3c3ecb19..20ab7a96eb 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2012-10-24 Joel Brobecker + + * doublest.c (convert_doublest_to_floatformat): Fix comparison + against maximum exponent value. + 2012-10-24 Joel Brobecker * ada-lang.h (ADA_KNOWN_RUNTIME_FILE_NAME_PATTERNS): Add entry for diff --git a/gdb/doublest.c b/gdb/doublest.c index f683002020..0308dac619 100644 --- a/gdb/doublest.c +++ b/gdb/doublest.c @@ -483,7 +483,7 @@ convert_doublest_to_floatformat (CONST struct floatformat *fmt, goto finalize_byteorder; } - if (exponent + fmt->exp_bias >= (1 << fmt->exp_len) - 1) + if (exponent + fmt->exp_bias >= (1 << fmt->exp_len)) { /* The value is too large to fit into the destination. Treat as infinity. */ diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index a7a1180365..633c0abb20 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2012-10-24 Joel Brobecker + + * gdb.base/ldbl_e308.c, gdb.base/ldbl_e308.exp: New files. + 2012-10-24 Joel Brobecker * gdb.ada/unc_arr_ptr_in_var_rec: New testcase. diff --git a/gdb/testsuite/gdb.base/ldbl_e308.c b/gdb/testsuite/gdb.base/ldbl_e308.c new file mode 100644 index 0000000000..8bbe01b49a --- /dev/null +++ b/gdb/testsuite/gdb.base/ldbl_e308.c @@ -0,0 +1,26 @@ +/* Copyright (C) 2012 Free Software Foundation, Inc. + + 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 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 . */ + +long double ldbl_308 = 2.0; + +int +main (void) +{ + ldbl_308 = ldbl_308 / 2; + + return 0; +} diff --git a/gdb/testsuite/gdb.base/ldbl_e308.exp b/gdb/testsuite/gdb.base/ldbl_e308.exp new file mode 100644 index 0000000000..89c54b5b57 --- /dev/null +++ b/gdb/testsuite/gdb.base/ldbl_e308.exp @@ -0,0 +1,31 @@ +# Copyright (C) 2012 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 . + +set testfile ldbl_e308 +set srcfile ${testfile}.c +if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile}] } { + return -1 +} + +if ![runto_main] { + untested ${testfile}.exp + return -1 +} + +gdb_test_no_output "set variable ldbl_308 = 1.6e+308l" + +gdb_test "print ldbl_308" \ + "= (1\..*e\\+308|inf)" +