Author: Igor Kudrin Date: 2025-10-21T20:01:08-07:00 New Revision: 64df8f83fe293b6c08477975cbb4451c76b51c54
URL: https://github.com/llvm/llvm-project/commit/64df8f83fe293b6c08477975cbb4451c76b51c54 DIFF: https://github.com/llvm/llvm-project/commit/64df8f83fe293b6c08477975cbb4451c76b51c54.diff LOG: [lldb][test] Fix TestEmptyFuncThreadStepOut.py (#161788) The test did not work as intended when the empty function `done()` contained prologue/epilogue code, because a breakpoint was set before the last instruction of the function, which caused the test to pass even with the fix from #126838 having been reverted. The test is intended to check a case when a breakpoint is set on a return instruction, which is the very last instruction of a function. When stepping out from this breakpoint, there is interaction between `ThreadPlanStepOut` and `ThreadPlanStepOverBreakpoint` that could lead to missing the stop location in the outer frame; the detailed explanation can be found in #126838. On `Linux/AArch64`, the source is compiled into: ``` > objdump -d main.o 0000000000000000 <done>: 0: d65f03c0 ret ``` So, when the command `bt set -n done` from the original test sets a breakpoint to the first instruction of `done()`, this instruction luckily also happens to be the last one. On `Linux/x86_64`, it compiles into: ``` > objdump -d main.o 0000000000000000 <done>: 0: 55 push %rbp 1: 48 89 e5 mov %rsp,%rbp 4: 5d pop %rbp 5: c3 ret ``` In this case, setting a breakpoint by function name means setting it several instructions before `ret`, which does not provoke the interaction between `ThreadPlanStepOut` and `ThreadPlanStepOverBreakpoint`. Added: Modified: lldb/test/API/functionalities/thread/finish-from-empty-func/TestEmptyFuncThreadStepOut.py lldb/test/API/functionalities/thread/finish-from-empty-func/main.c Removed: ################################################################################ diff --git a/lldb/test/API/functionalities/thread/finish-from-empty-func/TestEmptyFuncThreadStepOut.py b/lldb/test/API/functionalities/thread/finish-from-empty-func/TestEmptyFuncThreadStepOut.py index f5d3da530f4f5..c95a57ff55815 100644 --- a/lldb/test/API/functionalities/thread/finish-from-empty-func/TestEmptyFuncThreadStepOut.py +++ b/lldb/test/API/functionalities/thread/finish-from-empty-func/TestEmptyFuncThreadStepOut.py @@ -13,12 +13,31 @@ class FinishFromEmptyFunctionTestCase(TestBase): @skipIf(compiler="clang", compiler_version=['<', '17.0']) def test_finish_from_empty_function(self): - """Test that when stopped at a breakpoint in an empty function, finish leaves it correctly.""" + """Test that when stopped at a breakpoint located at the last instruction + of a function, finish leaves it correctly.""" self.build() - exe = self.getBuildArtifact("a.out") - target, process, thread, _ = lldbutil.run_to_name_breakpoint( - self, "done", exe_name=exe + target, _, thread, _ = lldbutil.run_to_source_breakpoint( + self, "// Set breakpoint here", lldb.SBFileSpec("main.c") ) + # Find the address of the last instruction of 'done()' and set a breakpoint there. + # Even though 'done()' is empty, it may contain prologue and epilogue code, so + # simply setting a breakpoint at the function can place it before 'ret'. + error = lldb.SBError() + ret_bp_addr = lldb.SBAddress() + while True: + thread.StepInstruction(False, error) + self.assertTrue(error.Success()) + frame = thread.GetSelectedFrame() + if "done" in frame.GetFunctionName(): + ret_bp_addr = frame.GetPCAddress() + elif ret_bp_addr.IsValid(): + # The entire function 'done()' has been stepped through, so 'ret_bp_addr' + # now contains the address of its last instruction, i.e. 'ret'. + break + ret_bp = target.BreakpointCreateByAddress(ret_bp_addr.GetLoadAddress(target)) + self.assertTrue(ret_bp.IsValid()) + # Resume the execution and hit the new breakpoint. + self.runCmd("cont") if self.TraceOn(): self.runCmd("bt") @@ -29,7 +48,6 @@ def test_finish_from_empty_function(self): ) self.assertTrue(safety_bp.IsValid()) - error = lldb.SBError() thread.StepOut(error) self.assertTrue(error.Success()) diff --git a/lldb/test/API/functionalities/thread/finish-from-empty-func/main.c b/lldb/test/API/functionalities/thread/finish-from-empty-func/main.c index bc66a548a89df..b3f90db5e2562 100644 --- a/lldb/test/API/functionalities/thread/finish-from-empty-func/main.c +++ b/lldb/test/API/functionalities/thread/finish-from-empty-func/main.c @@ -2,6 +2,7 @@ void done() {} int main() { puts("in main"); + done(); // Set breakpoint here done(); puts("leaving main"); return 0; _______________________________________________ lldb-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
