Author: Ilya Nozhkin
Date: 2022-02-28T14:29:29+08:00
New Revision: fd37d489cfef3bf7d06b2b43dac2ad1381cdc56b
URL:
https://github.com/llvm/llvm-project/commit/fd37d489cfef3bf7d06b2b43dac2ad1381cdc56b
DIFF:
https://github.com/llvm/llvm-project/commit/fd37d489cfef3bf7d06b2b43dac2ad1381cdc56b.diff
LOG: Set error message if ValueObjectRegister fails to write back to register
SetValueFromCString and SetData methods return false if register can't
be written but they don't set a error message. It sometimes confuses
callers of these methods because they try to get the error message in case of
failure but Status::AsCString returns nullptr.
For example, lldb-vscode crashes due to this bug if some register can't
be written. It invokes SBError::GetCString in case of error and doesn't
check whether the result is nullptr (see request_setVariable implementation in
lldb-vscode.cpp for more info).
Reviewed By: labath, clayborg
Differential Revision: https://reviews.llvm.org/D120319
Added:
Modified:
lldb/source/Core/ValueObjectRegister.cpp
lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py
Removed:
diff --git a/lldb/source/Core/ValueObjectRegister.cpp
b/lldb/source/Core/ValueObjectRegister.cpp
index fc436385e2455..e342f7265dfb1 100644
--- a/lldb/source/Core/ValueObjectRegister.cpp
+++ b/lldb/source/Core/ValueObjectRegister.cpp
@@ -269,26 +269,30 @@ bool ValueObjectRegister::SetValueFromCString(const char
*value_str,
// The new value will be in the m_data. Copy that into our register value.
error =
m_reg_value.SetValueFromString(_reg_info, llvm::StringRef(value_str));
- if (error.Success()) {
-if (m_reg_ctx_sp->WriteRegister(_reg_info, m_reg_value)) {
- SetNeedsUpdate();
- return true;
-} else
- return false;
- } else
+ if (!error.Success())
return false;
+
+ if (!m_reg_ctx_sp->WriteRegister(_reg_info, m_reg_value)) {
+error.SetErrorString("unable to write back to register");
+return false;
+ }
+
+ SetNeedsUpdate();
+ return true;
}
bool ValueObjectRegister::SetData(DataExtractor , Status ) {
error = m_reg_value.SetValueFromData(_reg_info, data, 0, false);
- if (error.Success()) {
-if (m_reg_ctx_sp->WriteRegister(_reg_info, m_reg_value)) {
- SetNeedsUpdate();
- return true;
-} else
- return false;
- } else
+ if (!error.Success())
return false;
+
+ if (!m_reg_ctx_sp->WriteRegister(_reg_info, m_reg_value)) {
+error.SetErrorString("unable to write back to register");
+return false;
+ }
+
+ SetNeedsUpdate();
+ return true;
}
bool ValueObjectRegister::ResolveValue(Scalar ) {
diff --git
a/lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py
b/lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py
index 46ecf2e5faeb8..d1948b6752753 100644
--- a/lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py
+++ b/lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py
@@ -133,6 +133,29 @@ def test_read_memory(self):
self.assertEqual(len(bytesread), 16)
self.dbg.DeleteTarget(target)
+@skipIfLLVMTargetMissing("X86")
+def test_write_register(self):
+"""Test that writing to register results in an error and that error
+ message is set."""
+target = self.dbg.CreateTarget("linux-x86_64.out")
+process = target.LoadCore("linux-x86_64.core")
+self.assertTrue(process, PROCESS_IS_VALID)
+
+thread = process.GetSelectedThread()
+self.assertTrue(thread)
+
+frame = thread.GetSelectedFrame()
+self.assertTrue(frame)
+
+reg_value = frame.FindRegister('eax')
+self.assertTrue(reg_value)
+
+error = lldb.SBError()
+success = reg_value.SetValueFromCString('10', error)
+self.assertFalse(success)
+self.assertTrue(error.Fail())
+self.assertIsNotNone(error.GetCString())
+
@skipIfLLVMTargetMissing("X86")
def test_FPR_SSE(self):
# check x86_64 core file
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