binutils-gdb/gdb/testsuite/gdb.base/step-test.exp

# This testcase is part of GDB, the GNU debugger.

# Copyright 1997-2025 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/>.  */
# step-test.exp -- Expect script to test stepping in gdb

standard_testfile .c

remote_exec build "rm -f ${binfile}"

if { [prepare_for_testing "prepare" $testfile $srcfile] != 0 } {
    return
}

if {![runto_main]} {
   return 0
}

# Set a breakpoint at line 45, if stepi then finish fails, we would
# run to the end of the program, which would mess up the rest of the tests.

# Vanilla step/next
#
gdb_test "next" ".*${decimal}.*x = 1;.*" "next 1"
gdb_test "step" ".*${decimal}.*y = 2;.*" "step 1"

# With count
#
gdb_test "next 2" ".*${decimal}.*w = w.*2;.*"
gdb_test "step 3" ".*${decimal}.*z = z.*5;.*"
gdb_test "next" ".*${decimal}.*callee.*OVER.*" "next 3"

# Step over call
#
gdb_test "next" ".*${decimal}.*callee.*INTO.*" "next over"

# Step into call
#
gdb_test "step" ".*${decimal}.*myglob.*"   "step into"

# Step out of call
#
# I wonder if this is really portable.  Are there any caller-saves
# platforms, on which `finish' will return you to some kind of pop
# instruction, which is attributed to the line containing the function
# call?

# On PA64, we end up at a different instruction than PA32.
# On IA-64, we also end up on callee instead of on the next line due
# to the restoration of the global pointer (which is a caller-save).
# Similarly on MIPS PIC targets.
set test "step out"
if { [istarget "ia64-*-*"] || [istarget "mips*-*-*"]} {
    gdb_test_multiple "finish" "$test" {
	-re ".*${decimal}.*a.*5.*= a.*3.*$gdb_prompt $" {
	    pass "$test"
	}
	-re ".*${decimal}.*callee.*INTO.*$gdb_prompt $" {
	    pass "$test"
	}
    }
} else {
    gdb_test "finish" ".*${decimal}.*a.*5.*= a.*3.*" "step out"
}

### Testing nexti and stepi.
###
### test_i NAME COMMAND HERE THERE
###
### Send COMMAND to gdb over and over, while the output matches the
### regexp HERE, followed by the gdb prompt.  Pass if the output
### eventually matches the regexp THERE, followed by the gdb prompt;
### fail if we have to iterate more than a hundred times, we time out
### talking to gdb, or we get output which is neither HERE nor THERE.  :)
###
### Use NAME as the name of the test.
###
### The exact regexps used are "$HERE.*$gdb_prompt $"
###                        and "$THERE.*$gdb_prompt $"
###
proc test_i {name command here there} {
    global gdb_prompt

    set i 0
    gdb_test_multiple "$command" "$name" {
	-re "$here.*$gdb_prompt $" {
	    # Have we gone for too many steps without seeing any progress?
	    if {[incr i] >= 100} {
		fail "$name (no progress after 100 steps)"
		return
	    }
	    send_gdb "$command\n"
	    exp_continue
	}
	-re "$there.*$gdb_prompt $" {
	    # We've reached the next line.  Rah.
	    pass "$name"
	    return
	}
    }
}

test_i "stepi to next line" "stepi" \
       ".*${decimal}.*a.*5.* = a.*3" \
       ".*${decimal}.*callee.*STEPI"

# Continue to step until we enter the function.  Also keep stepping
# if this passes through a (useless) PLT entry.
test_i "stepi into function" "stepi" \
       "(.*${decimal}.*callee.*STEPI|.* in callee@plt)" \
       ".*callee \\(\\) at .*step-test\\.c"

# Continue to step until we reach the function's body.  This makes it
# more likely that we've actually completed the prologue, so "finish"
# will work.
set alphanum_re "\[a-zA-Z0-9\]"
set pic_thunk_re  "__$alphanum_re*\\.get_pc_thunk\\.$alphanum_re* \\(\\)"
test_i "stepi into function's first source line" "stepi" \
	"(${decimal}.*int callee|$pic_thunk_re)" \
	".*${decimal}.*myglob.*; return 0;"

# Have to be careful here, if the finish does not work,
# then we may run to the end of the program, which
# will cause erroneous failures in the rest of the tests
set test "stepi: finish call"
gdb_test_multiple "finish" "$test" {
    -re ".*${decimal}.*callee.*NEXTI.*$gdb_prompt $" {
	pass "$test"
    }
    -re ".*(Program received|$inferior_exited_re).*$gdb_prompt $" {
	# Oops... We ran to the end of the program...  Better reset
	if {![runto_main]} {
	    return 0
	}
	if {![runto step-test.c:45]} {
	    return 0
	}
	fail "$test"
    }
    -re ".*${decimal}.*callee.*STEPI.*$gdb_prompt $" {
	# On PA64, we end up at a different instruction than PA32.
	# On IA-64, we end up on callee instead of on the following line due
	# to the restoration of the global pointer.
	# Similarly on MIPS PIC targets.
	if { [istarget "ia64-*-*"] || [istarget "mips*-*-*"] } {
	    test_i "$test" "stepi" \
		".*${decimal}.*callee.*STEPI"  ".*${decimal}.*callee.*NEXTI"
	} else {
	    fail "$test"
	}
    }
}

test_i "nexti over function" "nexti" \
       ".*${decimal}.*callee.*NEXTI" \
       ".*${decimal}.*y = w \\+ z;"

# On some platforms, if we try to step into a function call that
# passes a large structure by value, then we actually end up stepping
# into memcpy, bcopy, or some such --- GCC emits the call to pass the
# argument.  Opinion is bitterly divided about whether this is the
# right behavior for GDB or not, but we'll catch it here, so folks
# won't forget about it.
# Update 4/4/2002 - Regardless of which opinion you have, you would
# probably have to agree that gdb is currently behaving as designed,
# in the absence of additional code to not stop in functions used
# internally by the compiler.  Since the testsuite should be checking
# for conformance to the design, the correct behavior is to accept the
# cases where gdb stops in memcpy/bcopy.

gdb_test \
  "break [gdb_get_line_number "step-test.exp: large struct by value"]" \
  ".*Breakpoint.* at .*" \
  "set breakpoint at call to large_struct_by_value"
gdb_test "continue" \
	 ".*Breakpoint ${decimal},.*large_struct_by_value.*" \
	 "run to pass large struct"
set test "large struct by value"
gdb_test_multiple "step" "$test" {
    -re ".*step-test.exp: arrive here 1.*$gdb_prompt $" {
	pass "$test"
    }
    -re ".*(memcpy|bcopy).*$gdb_prompt $" {
	send_gdb "finish\n" ; gdb_expect -re "$gdb_prompt $"
	send_gdb "step\n"
	exp_continue
    }
}

gdb_continue_to_end