gdb/testsuite/gdb.base/unwind-on-each-insn.exp

# Copyright 2022 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/>.  */

# Single step through a simple (empty) function that was compiled
# without DWARF debug information.
#
# At each instruction check that the frame-id, and frame base address,
# are calculated correctly.
#
# Additionally, check we can correctly unwind to the previous frame,
# and that the previous stack-pointer value, and frame base address
# value, can be calculated correctly.

standard_testfile .c -foo.c

if {[prepare_for_testing_full "failed to prepare" \
	 [list ${testfile} debug \
	      $srcfile {debug} $srcfile2 {nodebug}]]} {
    return -1
}

if ![runto_main] then {
    return 0
}

# Return a two element list, the first element is the stack-pointer
# value (from the $sp register), and the second element is the frame
# base address (from the 'info frame' output).
proc get_sp_and_fba { testname } {
    with_test_prefix "get \$sp and frame base $testname" {
	set sp [get_hexadecimal_valueof "\$sp" "*UNKNOWN*"]

	set fba ""
	gdb_test_multiple "info frame" "" {
	    -re -wrap ".*Stack level ${::decimal}, frame at ($::hex):.*" {
		set fba $expect_out(1,string)
	    }
	}

	return [list $sp $fba]
    }
}

# Return the frame-id of the current frame, collected using the 'maint
# print frame-id' command.
proc get_fid { } {
    set fid ""
    gdb_test_multiple "maint print frame-id" "" {
	-re -wrap ".*frame-id for frame #${::decimal}: (.*)" {
	    set fid $expect_out(1,string)
	}
    }
    return $fid
}

# Record the current stack-pointer, and the frame base address.
lassign [get_sp_and_fba "in main"] main_sp main_fba
set main_fid [get_fid]

# Now enter the foo function.
gdb_breakpoint "*foo"
gdb_continue_to_breakpoint "enter foo"

# Figure out the range of addresses covered by this function.
set last_addr_in_foo ""

# The disassembly of foo on PowerPC looks like:
#     Dump of assembler code for function foo:
#  => 0x00000000100006dc <+0>:     std     r31,-8(r1)
#     0x00000000100006e0 <+4>:     stdu    r1,-48(r1)
#     0x00000000100006e4 <+8>:     mr      r31,r1
#     0x00000000100006e8 <+12>:    nop
#     0x00000000100006ec <+16>:    addi    r1,r31,48
#     0x00000000100006f0 <+20>:    ld      r31,-8(r1)
#     0x00000000100006f4 <+24>:    blr
#     0x00000000100006f8 <+28>:    .long 0x0
#     0x00000000100006fc <+32>:    .long 0x0
#     0x0000000010000700 <+36>:    .long 0x1000180
#     End of assembler dump.
#
# The last instruction in function foo is blr.  Need to ignore the .long
# entries following the blr instruction.

gdb_test_multiple "disassemble foo" "" {
    -re "^disassemble foo\r\n" {
	exp_continue
    }

    -re "^Dump of assembler code for function foo:\r\n" {
	exp_continue
    }

    -re "^...($hex) \[<>+0-9:\s\t\]*\.long\[\s\t\]*\[^\r\n\]*\r\n" {
	exp_continue
    }

    -re "^...($hex) \[^\r\n\]+\r\n" {
	set last_addr_in_foo $expect_out(1,string)
	exp_continue
    }

    -wrap -re "^End of assembler dump\\." {
	gdb_assert { ![string equal $last_addr_in_foo ""] } \
	    "found some addresses in foo"
	pass $gdb_test_name
    }
}

# Record the current stack-pointer, and the frame base address.
lassign [get_sp_and_fba "in foo"] foo_sp foo_fba
set foo_fid [get_fid]

for { set i_count 1 } { true } { incr i_count } {
    with_test_prefix "instruction ${i_count}" {

	# The current stack-pointer value can legitimately change
	# throughout the lifetime of a function, so we don't check the
	# current stack-pointer value.  But the frame base address
	# should not change, so we do check for that.
	lassign [get_sp_and_fba "for foo"] sp_value fba_value
	gdb_assert { $fba_value == $foo_fba }

	# The frame-id should never change within a function, so check
	# that now.
	set fid [get_fid]
	gdb_assert { [string equal $fid $foo_fid] } \
	    "check frame-id matches"

	# Check that the previous frame is 'main'.
	gdb_test "bt 2" "\r\n#1\\s+\[^\r\n\]+ in main \\(\\) .*"

	# Move up the stack (to main).
	gdb_test "up" \
	    "\r\n#1\\s+\[^\r\n\]+ in main \\(\\) .*"

	# Check we can unwind the stack-pointer and the frame base
	# address correctly.
	lassign [get_sp_and_fba "for main"] sp_value fba_value
	gdb_assert { $sp_value == $main_sp }
	gdb_assert { $fba_value == $main_fba }

	# Check we have a consistent value for main's frame-id.
	set fid [get_fid]
	gdb_assert { [string equal $fid $main_fid] }

	# Move back to the inner most frame.
	gdb_test "frame 0" ".*"

	set pc [get_hexadecimal_valueof "\$pc" "*UNKNOWN*"]
	if { $pc == $last_addr_in_foo } {
	    break
	}

	if { $i_count > 100 } {
	    # We expect a handful of instructions, if we reach 100,
	    # something is going wrong.  Avoid an infinite loop.
	    fail "exceeded max number of instructions"
	    break
	}

	gdb_test "stepi" ".*"
    }
}