1 # This testcase is part of GDB, the GNU debugger.
3 # Copyright 2004-2023 Free Software Foundation, Inc.
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12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 # GNU General Public License for more details.
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18 # Test "return", "finish", and "call" of functions that a scalar (int,
19 # float, enum) and/or take a single scalar parameter.
22 # Some targets can't call functions, so don't even bother with this
25 require {!target_info exists gdb,cannot_call_functions}
29 set allow_float_test [allow_float_test]
31 # Compile a variant of scalars.c using TYPE to specify the type of the
32 # parameter and return-type. Run the compiled program up to "main".
33 # Also updates the global "testfile" to reflect the most recent build.
35 proc start_scalars_test { type } {
44 # Create the additional flags
45 set flags "debug additional_flags=-DT=${type}"
46 set testfile "call-sc-${type}"
48 set binfile [standard_output_file ${testfile}]
49 if { [prepare_for_testing "failed to prepare" $binfile $srcfile $flags] } {
53 # Make certain that the output is consistent
54 with_test_prefix "testfile=$testfile" {
55 gdb_test_no_output "set print sevenbit-strings"
56 gdb_test_no_output "set print address off"
57 gdb_test_no_output "set width 0"
65 # Get the debug format
68 # check that type matches what was passed in
69 set test "ptype; ${testfile}"
71 gdb_test_multiple "ptype/r ${type}" "${test}" {
72 -re "type = (\[^\r\n\]*)\r\n$gdb_prompt $" {
73 set foo_t "$expect_out(1,string)"
74 pass "$test (${foo_t})"
77 gdb_test "ptype/r foo" "type = ${foo_t}" "ptype foo; ${testfile} $expect_out(1,string)"
81 # Given N (0..25), return the corresponding alphabetic letter in lower
82 # or upper case. This is ment to be i18n proof.
85 return [string range "abcdefghijklmnopqrstuvwxyz" $n $n]
89 return [string toupper [i2a $n]]
93 # Test GDB's ability to make inferior function calls to functions
94 # returning (or passing) in a single scalar.
96 # start_scalars_test() will have previously built a program with a
97 # specified scalar type. To ensure robustness of the output, "p/c" is
100 # This tests the code paths "which return-value convention?" and
101 # "extract return-value from registers" called by "infcall.c".
103 proc test_scalar_calls { } {
107 # Check that GDB can always extract a scalar-return value from an
108 # inferior function call. Since GDB always knows the location of
109 # an inferior function call's return value these should never fail
111 # Implemented by calling the parameterless function "fun" and then
112 # examining the return value printed by GDB.
114 set tests "call ${testfile}"
116 # Call fun, checking the printed return-value.
117 gdb_test "p/c fun()" "= 49 '1'" "p/c fun(); ${tests}"
119 # Check that GDB can always pass a structure to an inferior function.
120 # This test can never fail.
122 # Implemented by calling the one parameter function "Fun" which
123 # stores its parameter in the global variable "L". GDB then
124 # examining that global to confirm that the value is as expected.
126 gdb_test_no_output "call Fun(foo)" "call Fun(foo); ${tests}"
127 gdb_test "p/c L" " = 49 '1'" "p/c L; ${tests}"
130 # Test GDB's ability to both return a function (with "return" or
131 # "finish") and correctly extract/store any corresponding
134 # Check that GDB can consistently extract/store structure return
135 # values. There are two cases - returned in registers and returned in
136 # memory. For the latter case, the return value can't be found and a
137 # failure is "expected". However GDB must still both return the
138 # function and display the final source and line information.
140 # N identifies the number of elements in the struct that will be used
141 # for the test case. FAILS is a list of target tuples that will fail
144 # This tests the code paths "which return-value convention?", "extract
145 # return-value from registers", and "store return-value in registers".
146 # Unlike "test struct calls", this test is expected to "fail" when the
147 # return-value is in memory (GDB can't find the location). The test
148 # is in three parts: test "return"; test "finish"; check that the two
149 # are consistent. GDB can sometimes work for one command and not the
152 proc test_scalar_returns { } {
156 set tests "return ${testfile}"
159 # Check that "return" works.
161 # GDB must always force the return of a function that has
162 # a struct result. Dependant on the ABI, it may, or may not be
163 # possible to store the return value in a register.
165 # The relevant code looks like "L{n} = fun{n}()". The test forces
166 # "fun{n}" to "return" with an explicit value. Since that code
167 # snippet will store the returned value in "L{n}" the return
168 # is tested by examining "L{n}". This assumes that the
169 # compiler implemented this as fun{n}(&L{n}) and hence that when
170 # the value isn't stored "L{n}" remains unchanged. Also check for
171 # consistency between this and the "finish" case.
173 # Get into a call of fun
174 gdb_test "advance fun" \
175 "fun .*\[\r\n\]+\[0-9\].*return foo.*" \
176 "advance to fun for return; ${tests}"
178 # Check that the program invalidated the relevant global.
179 gdb_test "p/c L" " = 90 'Z'" "zed L for return; ${tests}"
181 # Force the "return". This checks that the return is always
182 # performed, and that GDB correctly reported this to the user.
183 # GDB 6.0 and earlier, when the return-value's location wasn't
184 # known, both failed to print a final "source and line" and misplaced
185 # the frame ("No frame").
187 # The test is writen so that it only reports one FAIL/PASS for the
188 # entire operation. The value returned is checked further down.
189 # "return_value_unknown", if non-empty, records why GDB realised
190 # that it didn't know where the return value was.
192 set test "return foo; ${tests}"
193 set return_value_unknown 0
194 set return_value_unimplemented 0
195 gdb_test_multiple "return foo" "${test}" {
197 # Ulgh, a struct return, remember this (still need prompt).
198 set return_value_unknown 1
201 -re "A structure or union" {
202 # Ulgh, a struct return, remember this (still need prompt).
203 set return_value_unknown 1
204 # Double ulgh. Architecture doesn't use return_value and
205 # hence hasn't implemented small structure return.
206 set return_value_unimplemented 1
209 -re "Make fun return now.*y or n. $" {
210 gdb_test_multiple "y" "${test}" {
211 -re "L *= fun.*${gdb_prompt} $" {
212 # Need to step off the function call
213 gdb_test "next" "zed.*" "${test}"
215 -re "zed \\(\\);.*$gdb_prompt $" {
222 # If the previous test did not work, the program counter might
223 # still be inside foo() rather than main(). Make sure the program
224 # counter is is main().
226 # This happens on ppc64 GNU/Linux with gcc 3.4.1 and a buggy GDB
228 set test "return foo; synchronize pc to main() for '${testfile}'"
229 for {set loop_count 0} {$loop_count < 2} {incr loop_count} {
230 gdb_test_multiple "backtrace 1" $test {
231 -re "#0.*main \\(\\).*${gdb_prompt} $" {
235 -re "#0.*fun \\(\\).*${gdb_prompt} $" {
236 if {$loop_count < 1} {
237 gdb_test "finish" ".*" ""
246 # Check that the return-value is as expected. At this stage we're
247 # just checking that GDB has returned a value consistent with
248 # "return_value_unknown" set above.
250 set test "value foo returned; ${tests}"
251 gdb_test_multiple "p/c L" "${test}" {
252 -re " = 49 '1'.*${gdb_prompt} $" {
253 if $return_value_unknown {
254 # This contradicts the above claim that GDB didn't
255 # know the location of the return-value.
261 -re " = 90 .*${gdb_prompt} $" {
262 if $return_value_unknown {
263 # The struct return case. Since any modification
264 # would be by reference, and that can't happen, the
265 # value should be unmodified and hence Z is expected.
266 # Is this a reasonable assumption?
269 # This contradicts the above claim that GDB knew
270 # the location of the return-value.
274 -re " = 57 .*${gdb_prompt} $" {
275 if $return_value_unknown {
276 # The struct return case.
277 # The return value is stored on the stack, and since GDB
278 # didn't override it, it still has value that was stored
279 # there in the earlier Foo(init) call.
282 # This contradicts the above claim that GDB knew
283 # the location of the return-value.
287 -re ".*${gdb_prompt} $" {
288 if $return_value_unimplemented {
289 # What a suprize. The architecture hasn't implemented
290 # return_value, and hence has to fail.
291 kfail "$test" gdb/1444
298 # Check that a "finish" works.
300 # This is almost but not quite the same as "call struct funcs".
301 # Architectures can have subtle differences in the two code paths.
303 # The relevant code snippet is "L{n} = fun{n}()". The program is
304 # advanced into a call to "fun{n}" and then that function is
305 # finished. The returned value that GDB prints, reformatted using
309 gdb_test "advance fun" \
310 "fun .*\[\r\n\]+\[0-9\].*return foo.*" \
311 "advance to fun for finish; ${tests}"
313 # Check that the program invalidated the relevant global.
314 gdb_test "p/c L" " = 90 'Z'" "zed L for finish; ${tests}"
316 # Finish the function, set 'finish_value_unknown" to non-empty if the
317 # return-value was not found.
318 set test "finish foo; ${tests}"
319 set finish_value_unknown 0
320 gdb_test_multiple "finish" "${test}" {
321 -re "Value returned is .*${gdb_prompt} $" {
324 -re "Cannot determine contents.*${gdb_prompt} $" {
325 # Expected bad value. For the moment this is ok.
326 set finish_value_unknown 1
331 # Re-print the last (return-value) using the more robust
332 # "p/c". If no return value was found, the 'Z' from the previous
333 # check that the variable was cleared, is printed.
334 set test "value foo finished; ${tests}"
335 gdb_test_multiple "p/c" "${test}" {
336 -re " = 49 '1'\[\r\n\]+${gdb_prompt} $" {
337 if $finish_value_unknown {
338 # This contradicts the above claim that GDB didn't
339 # know the location of the return-value.
345 -re " = 90 'Z'\[\r\n\]+${gdb_prompt} $" {
346 # The value didn't get found. This is "expected".
347 if $finish_value_unknown {
350 # This contradicts the above claim that GDB did
351 # know the location of the return-value.
357 # Finally, check that "return" and finish" have consistent
360 # Since both "return" and "finish" use equivalent "which
361 # return-value convention" logic, both commands should have
362 # identical can/can-not find return-value messages.
364 # Note that since "call" and "finish" use common code paths, a
365 # failure here is a strong indicator of problems with "store
366 # return-value" code paths. Suggest looking at "return_value"
367 # when investigating a fix.
369 set test "return and finish use same convention; ${tests}"
370 if {$finish_value_unknown == $return_value_unknown} {
373 kfail gdb/1444 "${test}"
377 # ABIs pass anything >8 or >16 bytes in memory but below that things
378 # randomly use register and/and structure conventions. Check all
379 # possible sized char scalars in that range. But only a restricted
380 # range of the other types.
382 # NetBSD/PPC returns "unnatural" (3, 5, 6, 7) sized scalars in memory.
384 # Test every single char struct from 1..17 in size. This is what the
385 # original "scalars" test was doing.
388 with_test_prefix $type {
389 if { [start_scalars_test $type] == -1 } {
401 # Assuming that any integer struct larger than 8 bytes goes in memory,
402 # come up with many and varied combinations of a return struct. For
403 # "struct calls" test just beyond that 8 byte boundary, for "struct
404 # returns" test up to that boundary.
406 # For floats, assumed that up to two struct elements can be stored in
407 # floating point registers, regardless of their size.
409 # The approx size of each structure it is computed assumed that tc=1,
410 # ts=2, ti=4, tl=4, tll=8, tf=4, td=8, tld=16, and that all fields are
411 # naturally aligned. Padding being added where needed.
413 # Approx size: 2, 4, ...
416 # Approx size: 4, 8, ...
419 # Approx size: 4, 8, ...
422 # Approx size: 8, 16, ...
425 if {$allow_float_test} {
426 # Approx size: 4, 8, ...
429 # Approx size: 8, 16, ...
432 # Approx size: 16, 32, ...
436 # Approx size: 4, 8, ...