From 78b86327b5301231005b08a7c589b2b58e6b4322 Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Thu, 6 Oct 2016 16:51:18 +0100 Subject: [PATCH] mips-tdep: Make FCRs always 32-bit Fix a regression from commit f8b73d13b7ca ("Target-described register support for MIPS"), , , which caused Floating Point Control Registers (FCRs) to be shown as 64-bit with 64-bit targets. This came from the legacy register format where all raw registers matched the width of the architecture regardless of their actual size. The correct size was then set in `mips_register_type' for cooked registers presented to the user, which in the case of FCRs meant the cooked size was always forced to 32 bits, reflecting their actual hardware size, even though the raw format carried them in 64-bit quantities on 64-bit targets. The upper 32 bits carried in the raw FCR format have always been don't-cares, not actually retrieved from hardware and never written back. With the introduction of XML register descriptions the layout of previously defined raw registers has been preserved, so as to keep existing register handling code unchanged and make it easier for GDB and `gdbserver' to interact with each other whether neither, either or both parties talking over RSP support XML register descriptions. For the XML-described case however `mips_register_type' is not used in raw to cooked register conversion, so any special cases coded there are not taken into account. Instead a new function, `mips_pseudo_register_type', has been introduced to handle size conversion, however lacking the special case for FCRs for the Linux and the now defunct IRIX target. The correct size has been maintained for embedded targets however, due to the bundling of FCRs with the embedded registers under the `rawnum >= MIPS_EMBED_FP0_REGNUM + 32' condition. Add the missing case to `mips_pseudo_register_type' then, referring to the FCR indices explicitly, and observing that between `MIPS_EMBED_FP0_REGNUM + 32' and `MIPS_FIRST_EMBED_REGNUM' there is an unused register slot whose contents are ignored so with the removal of embedded FCRs from under that condition we don't have to care about it and we can refer to the embedded registers starting from MIPS_FIRST_EMBED_REGNUM instead. Add a test case too so that we have means to check automatically that the correct user-visible size of FCRs is maintained. gdb/ * mips-tdep.c (mips_pseudo_register_type): Make FCRs always 32-bit. gdb/testsuite/ * gdb.arch/mips-fcr.exp: New test. * gdb.arch/mips-fcr.c: Source for the new test. --- gdb/ChangeLog | 5 +++ gdb/mips-tdep.c | 9 ++++- gdb/testsuite/ChangeLog | 5 +++ gdb/testsuite/gdb.arch/mips-fcr.c | 22 ++++++++++++ gdb/testsuite/gdb.arch/mips-fcr.exp | 54 +++++++++++++++++++++++++++++ 5 files changed, 94 insertions(+), 1 deletion(-) create mode 100644 gdb/testsuite/gdb.arch/mips-fcr.c create mode 100644 gdb/testsuite/gdb.arch/mips-fcr.exp diff --git a/gdb/ChangeLog b/gdb/ChangeLog index f13888b7095..1590c1b0623 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2016-10-06 Maciej W. Rozycki + + * mips-tdep.c (mips_pseudo_register_type): Make FCRs always + 32-bit. + 2016-10-06 Maciej W. Rozycki * mips-tdep.c (mips_pseudo_register_type): Rearrange comments diff --git a/gdb/mips-tdep.c b/gdb/mips-tdep.c index 615c9df00c9..b91dbfaa38e 100644 --- a/gdb/mips-tdep.c +++ b/gdb/mips-tdep.c @@ -1079,6 +1079,13 @@ mips_pseudo_register_type (struct gdbarch *gdbarch, int regnum) if (mips_float_register_p (gdbarch, rawnum)) return rawtype; + /* Floating-point control registers are always 32-bit even though for + backwards compatibility reasons 64-bit targets will transfer them + as 64-bit quantities even if using XML descriptions. */ + if (rawnum == mips_regnum (gdbarch)->fp_control_status + || rawnum == mips_regnum (gdbarch)->fp_implementation_revision) + return builtin_type (gdbarch)->builtin_int32; + /* Use pointer types for registers if we can. For n32 we can not, since we do not have a 64-bit pointer type. */ if (mips_abi_regsize (gdbarch) @@ -1111,7 +1118,7 @@ mips_pseudo_register_type (struct gdbarch *gdbarch, int regnum) with the displayed type. */ if (gdbarch_osabi (gdbarch) != GDB_OSABI_IRIX && gdbarch_osabi (gdbarch) != GDB_OSABI_LINUX - && rawnum >= MIPS_EMBED_FP0_REGNUM + 32 + && rawnum >= MIPS_FIRST_EMBED_REGNUM && rawnum <= MIPS_LAST_EMBED_REGNUM) return builtin_type (gdbarch)->builtin_int32; diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 223964e0d01..56d28acaf99 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2016-10-06 Maciej W. Rozycki + + * gdb.arch/mips-fcr.exp: New test. + * gdb.arch/mips-fcr.c: Source for the new test. + 2016-10-06 Maciej W. Rozycki * gdb.base/solib-disc.exp: Use `standard_output_file' diff --git a/gdb/testsuite/gdb.arch/mips-fcr.c b/gdb/testsuite/gdb.arch/mips-fcr.c new file mode 100644 index 00000000000..1545b21709f --- /dev/null +++ b/gdb/testsuite/gdb.arch/mips-fcr.c @@ -0,0 +1,22 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 2016 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 . */ + +int +main (void) +{ + return 0; +} diff --git a/gdb/testsuite/gdb.arch/mips-fcr.exp b/gdb/testsuite/gdb.arch/mips-fcr.exp new file mode 100644 index 00000000000..0e779a53e3b --- /dev/null +++ b/gdb/testsuite/gdb.arch/mips-fcr.exp @@ -0,0 +1,54 @@ +# Copyright (C) 2016 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 . + +# Contributed by Imagination Technologies, written by Maciej W. Rozycki. + +# Test MIPS Floating Point Control Register handling. + +if { ![istarget "mips*-*-*"] } then { + verbose "Skipping MIPS Floating Point Control Register tests." + return +} + +standard_testfile + +if { [prepare_for_testing ${testfile}.exp ${testfile}] } { + return +} + +if ![runto_main] { + return +} + +# First check if we have an FPU available in the first place. +gdb_test_multiple "show mipsfpu" "check for MIPS floating-point coprocessor" { + -re "The MIPS floating-point coprocessor .*\(absent\|unknown\).*$gdb_prompt $" { + unsupported "no MIPS floating-point coprocessor in the processor" + return + } + -re "The MIPS floating-point coprocessor .*$gdb_prompt $" { + verbose "MIPS floating-point coprocessor check successful." + } + default { + fail + return + } +} + +# Now check that FCRs are accessible and 32-bit wide. +gdb_test "info registers \$fcsr" "fcsr: $hex" +gdb_test "print sizeof \$fcsr" "\\\$$decimal = 4" +gdb_test "info registers \$fir" "fir: $hex" +gdb_test "print sizeof \$fir" "\\\$$decimal = 4" -- 2.30.2