forked from Imagelibrary/binutils-gdb
2a8339b71f
PPC64 multiple entry points, a normal entry point and an alternate entry point. The alternate entry point is to setup the Table of Contents (TOC) register before continuing at the normal entry point. When the TOC is already valid, the normal entry point is used, this is typically the case. The alternate entry point is typically referred to as the global entry point (GEP) in IBM. The normal entry point is typically referred to as the local entry point (LEP). When GDB is executing the finish command in reverse, the function finish_backward currently sets the break point at the alternate entry point. This issue is if the function, when executing in the forward direction, entered the function via the normal entry point, execution in the reverse direction will never sees the break point at the alternate entry point. In this case, the reverse execution continues until the next break point is encountered thus stopping at the wrong place. This patch adds a new address to struct execution_control_state to hold the address of the alternate entry point (GEP). The finish_backwards function is updated, if the stopping point is between the normal entry point (LEP) and the end of the function, a breakpoint is set at the normal entry point. If the stopping point is between the entry points, a breakpoint is set at the alternate entry point. This ensures that GDB will always stop at the normal entry point. If the function did enter via the alternate entry point, GDB will detect that and continue to execute backwards in the function until the alternate entry point is reached. The patch fixes the behavior of the reverse-finish command on PowerPC to match the behavior of the command on other platforms, specifically X86. The patch does not change the behavior of the command on X86. A new test is added to verify the reverse-finish command on PowerPC correctly stops at the instruction where the function call is made. The patch fixes 11 regression errors in test gdb.reverse/finish-precsave.exp and 11 regression errors in test gdb.reverse/finish-reverse.exp. The patch has been tested on Power 10 and X86 processor with no new regression failures.
225 lines
9.2 KiB
Plaintext
225 lines
9.2 KiB
Plaintext
# Copyright 2008-2023 Free Software Foundation, Inc.
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>. */
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# This file is part of the GDB testsuite. It tests reverse stepping.
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# Lots of code borrowed from "step-test.exp".
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# The reverse finish command should return from a function and stop on
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# the first instruction of the source line where the function call is made.
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# Specifically, the behavior should match doing a reverse next from the
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# first instruction in the function. GDB should only take one reverse step
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# or next statement to reach the previous source code line.
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# This testcase verifies the reverse-finish command stops at the first
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# instruction in the source code line where the function was called. There
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# are two scenarios that must be checked:
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# 1) gdb is at the entry point instruction for the function
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# 2) gdb is in the body of the function.
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# This test verifies the fix for gdb bugzilla:
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# https://sourceware.org/bugzilla/show_bug.cgi?id=29927
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# PowerPC supports two entry points to a function. The normal entry point
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# is called the local entry point (LEP). The alternate entry point is called
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# the global entry point (GEP). A function call via a function pointer
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# will entry via the GEP. A normal function call will enter via the LEP.
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#
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# This test has been expanded to include tests to verify the reverse-finish
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# command works properly if the function is called via the GEP. The original
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# test only verified the reverse-finish command for a normal call that used
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# the LEP.
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if ![supports_reverse] {
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return
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}
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standard_testfile
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if { [prepare_for_testing "failed to prepare" $testfile $srcfile] } {
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return -1
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}
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runto_main
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set target_remote [gdb_is_target_remote]
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if [supports_process_record] {
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# Activate process record/replay.
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gdb_test_no_output "record" "turn on process record for test1"
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}
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### TEST 1: reverse finish from the entry point instruction (LEP) in
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### function1 when called using the normal entry point (LEP).
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# Set breakpoint at call to function1 in main.
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set bp_LEP_test [gdb_get_line_number "CALL VIA LEP" $srcfile]
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gdb_breakpoint $srcfile:$bp_LEP_test temporary
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# Continue to break point at function1 call in main.
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gdb_continue_to_breakpoint \
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"stopped at function1 entry point instruction to stepi into function" \
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".*$srcfile:$bp_LEP_test\r\n.*"
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# stepi until we see "{" indicating we entered function1
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repeat_cmd_until "stepi" "CALL VIA LEP" "{" "stepi into function1 call" "100"
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# The reverse-finish command should stop on the function call instruction
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# which is the last instruction in the source code line. A reverse-next
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# instruction should then stop at the first instruction in the same source
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# code line. Another revers-next instruction stops at the previous source
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# code line.
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gdb_test "reverse-finish" ".*function1 \\(a, b\\); // CALL VIA LEP.*" \
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"reverse-finish function1 LEP call from LEP "
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gdb_test "reverse-next" ".*function1 \\(a, b\\); // CALL VIA LEP" \
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"reverse next 1 LEP entry point function call from LEP"
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gdb_test "reverse-next" ".*b = 5;.*" "reverse next 2, at b = 5, call from LEP"
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gdb_test "reverse-continue" ".*" "setup for test 2"
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# Turn off record to clear logs and turn on again
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gdb_test "record stop" "Process record is stopped.*" \
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"turn off process record for test1"
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gdb_test_no_output "record" "turn on process record for test2"
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### TEST 2: reverse finish from the body of function1.
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# Set breakpoint at call to function1 in main.
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gdb_breakpoint $srcfile:$bp_LEP_test temporary
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# Continue to break point at function1 call in main.
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gdb_continue_to_breakpoint \
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"at function1 entry point instruction to step to body of function" \
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".*$srcfile:$bp_LEP_test\r\n.*"
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# do a step instruction to get to the body of the function
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gdb_test "step" ".*int ret = 0;.*" "step test 1"
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# The reverse-finish command should stop on the function call instruction
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# which is the last instruction in the source code line. A reverse-next
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# instruction should then stop at the first instruction in the same source
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# code line. Another revers-next instruction stops at the previous source
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# code line.
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gdb_test "reverse-finish" ".*function1 \\(a, b\\); // CALL VIA LEP.*" \
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"reverse-finish function1 LEP call from function body"
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gdb_test "reverse-next" ".*function1 \\(a, b\\); // CALL VIA LEP.*" \
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"reverse next 1 LEP from function body"
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gdb_test "reverse-next" ".*b = 5;.*" \
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"reverse next 2 at b = 5, from function body"
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gdb_test "reverse-continue" ".*" "setup for test 3"
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# Turn off record to clear logs and turn on again
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gdb_test "record stop" "Process record is stopped.*" \
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"turn off process record for test2"
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gdb_test_no_output "record" "turn on process record for test3"
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### TEST 3: reverse finish from the alternate entry point instruction (GEP) in
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### function1 when called using the alternate entry point (GEP).
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# Set breakpoint at call to funp in main.
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set bp_GEP_test [gdb_get_line_number "CALL VIA GEP" $srcfile]
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gdb_breakpoint $srcfile:$bp_GEP_test temporary
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# Continue to break point at funp call in main.
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gdb_continue_to_breakpoint \
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"stopped at function1 entry point instruction to stepi into funp" \
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".*$srcfile:$bp_GEP_test\r\n.*"
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# stepi until we see "{" indicating we entered function.
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repeat_cmd_until "stepi" "CALL VIA GEP" "{" "stepi into funp call"
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# The reverse-finish command should stop on the function call instruction
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# which is the last instruction in the source code line. A reverse-next
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# instruction should then stop at the first instruction in the same source
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# code line. Another revers-next instruction stops at the previous source
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# code line.
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gdb_test "reverse-finish" ".*funp \\(a, b\\);.*" \
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"function1 GEP call call from GEP"
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gdb_test "reverse-next" ".*funp \\(a, b\\);.*" \
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"reverse next 1 GEP entry point function call from GEP"
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gdb_test "reverse-next" ".*b = 50;.*" "reverse next 2 at b = 50, call from GEP"
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gdb_test "reverse-continue" ".*" "setup for test 4"
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# Turn off record to clear logs and turn on again
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gdb_test "record stop" "Process record is stopped.*" \
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"turn off process record for test3"
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gdb_test_no_output "record" "turn on process record for test4"
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### TEST 4: reverse finish from between the GEP and LEP in
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### function1 when called using the alternate entry point (GEP).
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# Set breakpoint at call to funp in main.
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set bp_GEP_test [gdb_get_line_number "CALL VIA GEP" $srcfile]
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gdb_breakpoint $srcfile:$bp_GEP_test temporary
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# Continue to break point at funp call in main.
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gdb_continue_to_breakpoint \
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"stopped at function1 entry point instruction to stepi into funp again" \
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".*$srcfile:$bp_GEP_test\r\n.*"
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# stepi until we see "{" indicating we entered function.
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repeat_cmd_until "stepi" "CALL VIA GEP" "{" "stepi into funp call again"
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# do one more stepi so we are between the GEP and LEP.
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gdb_test "stepi" "{" "stepi to between GEP and LEP"
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# The reverse-finish command should stop on the function call instruction
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# which is the last instruction in the source code line. A reverse-next
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# instruction should then stop at the first instruction in the same source
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# code line. Another revers-next instruction stops at the previous source
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# code line.
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gdb_test "reverse-finish" ".*funp \\(a, b\\);.*" \
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"function1 GEP call call from GEP again"
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gdb_test "reverse-next" ".*funp \\(a, b\\);.*" \
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"reverse next 1 GEP entry point function call from GEP again"
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gdb_test "reverse-next" ".*b = 50;.*" \
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"reverse next 2 at b = 50, call from GEP again"
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gdb_test "reverse-continue" ".*" "setup for test 5"
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# Turn off record to clear logs and turn on again
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gdb_test "record stop" "Process record is stopped.*" \
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"turn off process record for test4"
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gdb_test_no_output "record" "turn on process record for test5"
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### TEST 5: reverse finish from the body of function 1 when calling using the
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### alternate entrypoint (GEP).
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gdb_breakpoint $srcfile:$bp_GEP_test temporary
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# Continue to break point at funp call.
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gdb_continue_to_breakpoint \
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"at function1 entry point instruction to step to body of funp call" \
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".*$srcfile:$bp_GEP_test\r\n.*"
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# Step into body of funp, called via GEP.
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gdb_test "step" ".*int ret = 0;.*" "step test 2"
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# The reverse-finish command should stop on the function call instruction
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# which is the last instruction in the source code line. A reverse-next
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# instruction should then stop at the first instruction in the same source
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# code line. Another revers-next instruction stops at the previous source
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# code line.
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gdb_test "reverse-finish" ".*funp \\(a, b\\);.*" \
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"reverse-finish function1 GEP call, from function body "
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gdb_test "reverse-next" ".*funp \\(a, b\\);.*" \
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"reverse next 1 GEP call from function body"
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gdb_test "reverse-next" ".*b = 50;.*" \
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"reverse next 2 at b = 50 from function body"
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