This revision was automatically updated to reflect the committed changes.
Closed by commit rG0a840ef80059: [lldb] Copy m_behaves_like_zeroth_frame on
stack frame update (authored by tatyana-krasnukha).
Changed prior to commit:
https://reviews.llvm.org/D75975?vs=249561&id=250549#toc
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D75975/new/
https://reviews.llvm.org/D75975
Files:
lldb/source/Target/StackFrame.cpp
lldb/test/API/functionalities/unwind/zeroth_frame/Makefile
lldb/test/API/functionalities/unwind/zeroth_frame/TestZerothFrame.py
lldb/test/API/functionalities/unwind/zeroth_frame/main.c
Index: lldb/test/API/functionalities/unwind/zeroth_frame/main.c
===================================================================
--- /dev/null
+++ lldb/test/API/functionalities/unwind/zeroth_frame/main.c
@@ -0,0 +1,8 @@
+void func_inner() {
+ int a = 1; // Set breakpoint 1 here
+}
+
+int main() {
+ func_inner();
+ return 0; // Set breakpoint 2 here
+}
Index: lldb/test/API/functionalities/unwind/zeroth_frame/TestZerothFrame.py
===================================================================
--- /dev/null
+++ lldb/test/API/functionalities/unwind/zeroth_frame/TestZerothFrame.py
@@ -0,0 +1,96 @@
+"""
+Test that line information is recalculated properly for a frame when it moves
+from the middle of the backtrace to a zero index.
+
+This is a regression test for a StackFrame bug, where whether frame is zero or
+not depends on an internal field. When LLDB was updating its frame list value
+of the field wasn't copied into existing StackFrame instances, so those
+StackFrame instances, would use an incorrect line entry evaluation logic in
+situations if it was in the middle of the stack frame list (not zeroth), and
+then moved to the top position. The difference in logic is that for zeroth
+frames line entry is returned for program counter, while for other frame
+(except for those that "behave like zeroth") it is for the instruction
+preceding PC, as PC points to the next instruction after function call. When
+the bug is present, when execution stops at the second breakpoint
+SBFrame.GetLineEntry() returns line entry for the previous line, rather than
+the one with a breakpoint. Note that this is specific to
+SBFrame.GetLineEntry(), SBFrame.GetPCAddress().GetLineEntry() would return
+correct entry.
+
+This bug doesn't reproduce through an LLDB interpretator, however it happens
+when using API directly, for example in LLDB-MI.
+"""
+
+from __future__ import print_function
+
+
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class ZerothFrame(TestBase):
+ mydir = TestBase.compute_mydir(__file__)
+
+ def test(self):
+ """
+ Test that line information is recalculated properly for a frame when it moves
+ from the middle of the backtrace to a zero index.
+ """
+ self.build()
+ self.setTearDownCleanup()
+
+ exe = self.getBuildArtifact("a.out")
+ target = self.dbg.CreateTarget(exe)
+ self.assertTrue(target, VALID_TARGET)
+
+ bp1_line = line_number('main.c', '// Set breakpoint 1 here')
+ bp2_line = line_number('main.c', '// Set breakpoint 2 here')
+
+ lldbutil.run_break_set_by_file_and_line(
+ self,
+ 'main.c',
+ bp1_line,
+ num_expected_locations=1)
+ lldbutil.run_break_set_by_file_and_line(
+ self,
+ 'main.c',
+ bp2_line,
+ num_expected_locations=1)
+
+ process = target.LaunchSimple(
+ None, None, self.get_process_working_directory())
+ self.assertTrue(process, VALID_PROCESS)
+
+ thread = process.GetThreadAtIndex(0)
+ if self.TraceOn():
+ print("Backtrace at the first breakpoint:")
+ for f in thread.frames:
+ print(f)
+ # Check that we have stopped at correct breakpoint.
+ self.assertEqual(
+ process.GetThreadAtIndex(0).frame[0].GetLineEntry().GetLine(),
+ bp1_line,
+ "LLDB reported incorrect line number.")
+
+ # Important to use SBProcess::Continue() instead of
+ # self.runCmd('continue'), because the problem doesn't reproduce with
+ # 'continue' command.
+ process.Continue()
+
+ thread = process.GetThreadAtIndex(0)
+ if self.TraceOn():
+ print("Backtrace at the second breakpoint:")
+ for f in thread.frames:
+ print(f)
+ # Check that we have stopped at the breakpoint
+ self.assertEqual(
+ thread.frame[0].GetLineEntry().GetLine(),
+ bp2_line,
+ "LLDB reported incorrect line number.")
+ # Double-check with GetPCAddress()
+ self.assertEqual(
+ thread.frame[0].GetLineEntry().GetLine(),
+ thread.frame[0].GetPCAddress().GetLineEntry().GetLine(),
+ "LLDB reported incorrect line number.")
Index: lldb/test/API/functionalities/unwind/zeroth_frame/Makefile
===================================================================
--- /dev/null
+++ lldb/test/API/functionalities/unwind/zeroth_frame/Makefile
@@ -0,0 +1,3 @@
+C_SOURCES := main.c
+
+include Makefile.rules
Index: lldb/source/Target/StackFrame.cpp
===================================================================
--- lldb/source/Target/StackFrame.cpp
+++ lldb/source/Target/StackFrame.cpp
@@ -1861,6 +1861,7 @@
m_concrete_frame_index = curr_frame.m_concrete_frame_index;
m_reg_context_sp = curr_frame.m_reg_context_sp;
m_frame_code_addr = curr_frame.m_frame_code_addr;
+ m_behaves_like_zeroth_frame = curr_frame.m_behaves_like_zeroth_frame;
assert(!m_sc.target_sp || !curr_frame.m_sc.target_sp ||
m_sc.target_sp.get() == curr_frame.m_sc.target_sp.get());
assert(!m_sc.module_sp || !curr_frame.m_sc.module_sp ||
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