[Lldb-commits] [lldb] r343029 - Change the unwinder to not use a hard-coded limit on the
Jason Molenda via lldb-commits
lldb-commits at lists.llvm.org
Tue Sep 25 14:01:54 PDT 2018
Author: jmolenda
Date: Tue Sep 25 14:01:54 2018
New Revision: 343029
URL: http://llvm.org/viewvc/llvm-project?rev=343029&view=rev
Log:
Change the unwinder to not use a hard-coded limit on the
max number of stack frames to backtrace, make it a setting,
target.process.thread.max-backtrace-depth.
Add a test case for the setting.
<rdar://problem/28759559>
Added:
lldb/trunk/packages/Python/lldbsuite/test/functionalities/thread/backtrace_limit/
lldb/trunk/packages/Python/lldbsuite/test/functionalities/thread/backtrace_limit/Makefile
lldb/trunk/packages/Python/lldbsuite/test/functionalities/thread/backtrace_limit/TestBacktraceLimit.py
lldb/trunk/packages/Python/lldbsuite/test/functionalities/thread/backtrace_limit/main.cpp
Modified:
lldb/trunk/include/lldb/Target/Thread.h
lldb/trunk/source/Plugins/Process/Utility/UnwindLLDB.cpp
lldb/trunk/source/Target/Thread.cpp
Modified: lldb/trunk/include/lldb/Target/Thread.h
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/include/lldb/Target/Thread.h?rev=343029&r1=343028&r2=343029&view=diff
==============================================================================
--- lldb/trunk/include/lldb/Target/Thread.h (original)
+++ lldb/trunk/include/lldb/Target/Thread.h Tue Sep 25 14:01:54 2018
@@ -57,6 +57,8 @@ public:
bool GetStepInAvoidsNoDebug() const;
bool GetStepOutAvoidsNoDebug() const;
+
+ uint64_t GetMaxBacktraceDepth() const;
};
typedef std::shared_ptr<ThreadProperties> ThreadPropertiesSP;
Added: lldb/trunk/packages/Python/lldbsuite/test/functionalities/thread/backtrace_limit/Makefile
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/packages/Python/lldbsuite/test/functionalities/thread/backtrace_limit/Makefile?rev=343029&view=auto
==============================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/functionalities/thread/backtrace_limit/Makefile (added)
+++ lldb/trunk/packages/Python/lldbsuite/test/functionalities/thread/backtrace_limit/Makefile Tue Sep 25 14:01:54 2018
@@ -0,0 +1,6 @@
+LEVEL = ../../../make
+
+CXXFLAGS += -std=c++11
+CXX_SOURCES := main.cpp
+ENABLE_THREADS := YES
+include $(LEVEL)/Makefile.rules
Added: lldb/trunk/packages/Python/lldbsuite/test/functionalities/thread/backtrace_limit/TestBacktraceLimit.py
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/packages/Python/lldbsuite/test/functionalities/thread/backtrace_limit/TestBacktraceLimit.py?rev=343029&view=auto
==============================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/functionalities/thread/backtrace_limit/TestBacktraceLimit.py (added)
+++ lldb/trunk/packages/Python/lldbsuite/test/functionalities/thread/backtrace_limit/TestBacktraceLimit.py Tue Sep 25 14:01:54 2018
@@ -0,0 +1,31 @@
+"""
+Test that the target.process.thread.max-backtrace-depth setting works.
+"""
+
+import unittest2
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class BacktraceLimitSettingTest(TestBase):
+
+ mydir = TestBase.compute_mydir(__file__)
+ NO_DEBUG_INFO_TESTCASE = True
+
+ def setUp(self):
+ # Call super's setUp().
+ TestBase.setUp(self)
+
+ def test_backtrace_depth(self):
+ """Test that the max-backtrace-depth setting limits backtraces."""
+ self.build()
+ self.main_source_file = lldb.SBFileSpec("main.cpp")
+ (target, process, thread, bkpt) = lldbutil.run_to_source_breakpoint(self,
+ "Set a breakpoint here", self.main_source_file)
+ interp = self.dbg.GetCommandInterpreter()
+ result = lldb.SBCommandReturnObject()
+ interp.HandleCommand("settings set target.process.thread.max-backtrace-depth 30", result)
+ self.assertEqual(True, result.Succeeded())
+ self.assertEqual(30, thread.GetNumFrames())
Added: lldb/trunk/packages/Python/lldbsuite/test/functionalities/thread/backtrace_limit/main.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/packages/Python/lldbsuite/test/functionalities/thread/backtrace_limit/main.cpp?rev=343029&view=auto
==============================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/functionalities/thread/backtrace_limit/main.cpp (added)
+++ lldb/trunk/packages/Python/lldbsuite/test/functionalities/thread/backtrace_limit/main.cpp Tue Sep 25 14:01:54 2018
@@ -0,0 +1,13 @@
+int bottom () {
+ return 1; // Set a breakpoint here
+}
+int foo(int in) {
+ if (in > 0)
+ return foo(--in) + 5;
+ else
+ return bottom();
+}
+int main()
+{
+ return foo(500);
+}
Modified: lldb/trunk/source/Plugins/Process/Utility/UnwindLLDB.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/Utility/UnwindLLDB.cpp?rev=343029&r1=343028&r2=343029&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/Process/Utility/UnwindLLDB.cpp (original)
+++ lldb/trunk/source/Plugins/Process/Utility/UnwindLLDB.cpp Tue Sep 25 14:01:54 2018
@@ -130,6 +130,8 @@ UnwindLLDB::CursorSP UnwindLLDB::GetOneM
RegisterContextLLDBSP reg_ctx_sp(new RegisterContextLLDB(
m_thread, prev_frame->reg_ctx_lldb_sp, cursor_sp->sctx, cur_idx, *this));
+ uint64_t max_stack_depth = m_thread.GetMaxBacktraceDepth();
+
// We want to detect an unwind that cycles erroneously and stop backtracing.
// Don't want this maximum unwind limit to be too low -- if you have a
// backtrace with an "infinitely recursing" bug, it will crash when the stack
@@ -138,7 +140,7 @@ UnwindLLDB::CursorSP UnwindLLDB::GetOneM
// unwind at 10,000 or something. Realistically anything over around 200,000
// is going to blow out the stack space. If we're still unwinding at that
// point, we're probably never going to finish.
- if (cur_idx > 300000) {
+ if (cur_idx >= max_stack_depth) {
if (log)
log->Printf("%*sFrame %d unwound too many frames, assuming unwind has "
"gone astray, stopping.",
Modified: lldb/trunk/source/Target/Thread.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Target/Thread.cpp?rev=343029&r1=343028&r2=343029&view=diff
==============================================================================
--- lldb/trunk/source/Target/Thread.cpp (original)
+++ lldb/trunk/source/Target/Thread.cpp Tue Sep 25 14:01:54 2018
@@ -80,6 +80,8 @@ static PropertyDefinition g_properties[]
nullptr, "A list of libraries that source stepping won't stop in."},
{"trace-thread", OptionValue::eTypeBoolean, false, false, nullptr, nullptr,
"If true, this thread will single-step and log execution."},
+ {"max-backtrace-depth", OptionValue::eTypeUInt64, false, 300000, nullptr,
+ nullptr, "Maximum number of frames to backtrace."},
{nullptr, OptionValue::eTypeInvalid, false, 0, nullptr, nullptr, nullptr}};
enum {
@@ -87,7 +89,8 @@ enum {
ePropertyStepOutAvoidsNoDebug,
ePropertyStepAvoidRegex,
ePropertyStepAvoidLibraries,
- ePropertyEnableThreadTrace
+ ePropertyEnableThreadTrace,
+ ePropertyMaxBacktraceDepth
};
class ThreadOptionValueProperties : public OptionValueProperties {
@@ -165,6 +168,12 @@ bool ThreadProperties::GetStepOutAvoidsN
nullptr, idx, g_properties[idx].default_uint_value != 0);
}
+uint64_t ThreadProperties::GetMaxBacktraceDepth() const {
+ const uint32_t idx = ePropertyMaxBacktraceDepth;
+ return m_collection_sp->GetPropertyAtIndexAsUInt64(
+ nullptr, idx, g_properties[idx].default_uint_value != 0);
+}
+
//------------------------------------------------------------------
// Thread Event Data
//------------------------------------------------------------------
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