Make result variables obey their dynamic values in subsequent expressions #168611
+387
−51
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
…ions. At this stage, result variables work, but persistent expression variables do not. I have a test that which should work but does not.
Member
|
@llvm/pr-subscribers-lldb Author: None (jimingham) ChangesWhen you run an expression and the result has a dynamic type that is different from the expression's static result type, we print the result variable using the dynamic type, but at present when you use the result variable in an expression later on, we only give you access to the static type. For instance: The static return type of that function is This patch makes lldb retain the dynamic type of the result variable (and ditto for persistent result variables). It also adds more testing of expression result variables with various types of dynamic values, to ensure we can access both the ivars and methods of the type we print the result as. Patch is 26.88 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/168611.diff 10 Files Affected:
diff --git a/lldb/include/lldb/Expression/ExpressionVariable.h b/lldb/include/lldb/Expression/ExpressionVariable.h
index 68fa1c878a0e3..8b7eee63f0f92 100644
--- a/lldb/include/lldb/Expression/ExpressionVariable.h
+++ b/lldb/include/lldb/Expression/ExpressionVariable.h
@@ -33,11 +33,21 @@ class ExpressionVariable
virtual ~ExpressionVariable() = default;
- llvm::Expected<uint64_t> GetByteSize() { return m_frozen_sp->GetByteSize(); }
+ llvm::Expected<uint64_t> GetByteSize() {
+ return GetValueObject()->GetByteSize();
+
+ }
ConstString GetName() { return m_frozen_sp->GetName(); }
- lldb::ValueObjectSP GetValueObject() { return m_frozen_sp; }
+ lldb::ValueObjectSP GetValueObject() {
+ lldb::ValueObjectSP dyn_sp =
+ m_frozen_sp->GetDynamicValue(lldb::eDynamicDontRunTarget);
+ if (dyn_sp && dyn_sp->UpdateValueIfNeeded())
+ return dyn_sp;
+ else
+ return m_frozen_sp;
+ }
uint8_t *GetValueBytes();
@@ -52,7 +62,7 @@ class ExpressionVariable
Value::ContextType::RegisterInfo, const_cast<RegisterInfo *>(reg_info));
}
- CompilerType GetCompilerType() { return m_frozen_sp->GetCompilerType(); }
+ CompilerType GetCompilerType() { return GetValueObject()->GetCompilerType(); }
void SetCompilerType(const CompilerType &compiler_type) {
m_frozen_sp->GetValue().SetCompilerType(compiler_type);
@@ -60,22 +70,32 @@ class ExpressionVariable
void SetName(ConstString name) { m_frozen_sp->SetName(name); }
- // this function is used to copy the address-of m_live_sp into m_frozen_sp
- // this is necessary because the results of certain cast and pointer-
+ // This function is used to copy the address-of m_live_sp into m_frozen_sp.
+ // This is necessary because the results of certain cast and pointer-
// arithmetic operations (such as those described in bugzilla issues 11588
// and 11618) generate frozen objects that do not have a valid address-of,
// which can be troublesome when using synthetic children providers.
// Transferring the address-of the live object solves these issues and
- // provides the expected user-level behavior
- void TransferAddress(bool force = false) {
- if (m_live_sp.get() == nullptr)
- return;
-
- if (m_frozen_sp.get() == nullptr)
- return;
-
- if (force || (m_frozen_sp->GetLiveAddress() == LLDB_INVALID_ADDRESS))
- m_frozen_sp->SetLiveAddress(m_live_sp->GetLiveAddress());
+ // provides the expected user-level behavior.
+ // The other job we do in TransferAddress is adjust the value in the live
+ // address slot in the target for the "offset to top" in multiply inherited
+ // class hierarchies.
+ void TransferAddress(bool force = false);
+
+ // When we build an expression variable we know whether we're going to use the
+ // static or dynamic result. If we present the dynamic value once, we should
+ // use the dynamic value in future references to the variable, so we record
+ // that fact here.
+ void PreserveDynamicOption(lldb::DynamicValueType dyn_type) {
+ m_dyn_option = dyn_type;
+ }
+ // We don't try to get the dynamic value of the live object when we fetch
+ // it here. The live object describes the container of the value in the
+ // target, but it's type is of the object for convenience. So it can't
+ // produce the dynamic value. Instead, we use TransferAddress to adjust the
+ // value held by the LiveObject.
+ lldb::ValueObjectSP GetLiveObject() {
+ return m_live_sp;
}
enum Flags {
@@ -110,6 +130,14 @@ class ExpressionVariable
/// These members should be private.
/// @{
/// A value object whose value's data lives in host (lldb's) memory.
+ /// The m_frozen_sp holds the data & type of the expression variable or result
+ /// in the host. The m_frozen_sp also can present a dynamic value if one is
+ /// available.
+ /// The m_frozen_sp manages the copy of this value in m_frozen_sp that we
+ /// insert in the target so that it can be referred to in future expressions.
+ /// We don't actually use the contents of the live_sp to create the value in
+ /// the target, that comes from the frozen sp. The live_sp is mostly to track
+ /// the target-side of the value.
lldb::ValueObjectSP m_frozen_sp;
/// The ValueObject counterpart to m_frozen_sp that tracks the value in
/// inferior memory. This object may not always exist; its presence depends on
@@ -119,6 +147,9 @@ class ExpressionVariable
/// track.
lldb::ValueObjectSP m_live_sp;
/// @}
+
+ //LLVMCastKind m_kind;
+ lldb::DynamicValueType m_dyn_option = lldb::eNoDynamicValues;
};
/// \class ExpressionVariableList ExpressionVariable.h
diff --git a/lldb/packages/Python/lldbsuite/test/lldbtest.py b/lldb/packages/Python/lldbsuite/test/lldbtest.py
index 8c1eea97620e2..927fa7679bbb5 100644
--- a/lldb/packages/Python/lldbsuite/test/lldbtest.py
+++ b/lldb/packages/Python/lldbsuite/test/lldbtest.py
@@ -2540,6 +2540,7 @@ def expect_expr(
result_value=None,
result_type=None,
result_children=None,
+ options=None
):
"""
Evaluates the given expression and verifies the result.
@@ -2556,7 +2557,8 @@ def expect_expr(
)
frame = self.frame()
- options = lldb.SBExpressionOptions()
+ if not options:
+ options = lldb.SBExpressionOptions()
# Disable fix-its that tests don't pass by accident.
options.SetAutoApplyFixIts(False)
diff --git a/lldb/source/Expression/ExpressionVariable.cpp b/lldb/source/Expression/ExpressionVariable.cpp
index 9e8ea60f8e052..9d361bc853620 100644
--- a/lldb/source/Expression/ExpressionVariable.cpp
+++ b/lldb/source/Expression/ExpressionVariable.cpp
@@ -20,15 +20,16 @@ char ExpressionVariable::ID;
ExpressionVariable::ExpressionVariable() : m_flags(0) {}
uint8_t *ExpressionVariable::GetValueBytes() {
+ lldb::ValueObjectSP valobj_sp = GetValueObject();
std::optional<uint64_t> byte_size =
- llvm::expectedToOptional(m_frozen_sp->GetByteSize());
+ llvm::expectedToOptional(valobj_sp->GetByteSize());
if (byte_size && *byte_size) {
- if (m_frozen_sp->GetDataExtractor().GetByteSize() < *byte_size) {
- m_frozen_sp->GetValue().ResizeData(*byte_size);
- m_frozen_sp->GetValue().GetData(m_frozen_sp->GetDataExtractor());
+ if (valobj_sp->GetDataExtractor().GetByteSize() < *byte_size) {
+ valobj_sp->GetValue().ResizeData(*byte_size);
+ valobj_sp->GetValue().GetData(valobj_sp->GetDataExtractor());
}
return const_cast<uint8_t *>(
- m_frozen_sp->GetDataExtractor().GetDataStart());
+ valobj_sp->GetDataExtractor().GetDataStart());
}
return nullptr;
}
@@ -37,6 +38,69 @@ char PersistentExpressionState::ID;
PersistentExpressionState::PersistentExpressionState() = default;
+void ExpressionVariable::TransferAddress(bool force) {
+ if (m_live_sp.get() == nullptr)
+ return;
+
+ if (m_frozen_sp.get() == nullptr)
+ return;
+
+ if (force || (m_frozen_sp->GetLiveAddress() == LLDB_INVALID_ADDRESS)) {
+ lldb::addr_t live_addr = m_live_sp->GetLiveAddress();
+ m_frozen_sp->SetLiveAddress(live_addr);
+ // One more detail, if there's an offset_to_top in the frozen_sp, then we
+ // need to appy that offset by hand. The live_sp can't compute this
+ // itself as its type is the type of the contained object which confuses
+ // the dynamic type calculation. So we have to update the contents of the
+ // m_live_sp with the dynamic value.
+ // Note: We could get this right when we originally write the address, but
+ // that happens in different ways for the various flavors of
+ // Entity*::Materialize, but everything comes through here, and it's just
+ // one extra memory write.
+
+ // You can only have an "offset_to_top" with pointers or references:
+ if (!m_frozen_sp->GetCompilerType().IsPointerOrReferenceType())
+ return;
+
+ lldb::ProcessSP process_sp = m_frozen_sp->GetProcessSP();
+ // If there's no dynamic value, then there can't be an offset_to_top:
+ if (!process_sp
+ || !process_sp->IsPossibleDynamicValue(*(m_frozen_sp.get())))
+ return;
+
+ lldb::ValueObjectSP dyn_sp = m_frozen_sp->GetDynamicValue(m_dyn_option);
+ if (!dyn_sp)
+ return;
+ ValueObject::AddrAndType static_addr = m_frozen_sp->GetPointerValue();
+ if (static_addr.type != eAddressTypeLoad)
+ return;
+
+ ValueObject::AddrAndType dynamic_addr= dyn_sp->GetPointerValue();
+ if (dynamic_addr.type != eAddressTypeLoad || static_addr.address == dynamic_addr.address)
+ return;
+
+ Status error;
+ Log *log = GetLog(LLDBLog::Expressions);
+ lldb::addr_t cur_value
+ = process_sp->ReadPointerFromMemory(live_addr, error);
+ if (error.Fail())
+ return;
+
+ if (cur_value != static_addr.address) {
+ LLDB_LOG(log, "Stored value: {0} read from {1} doesn't "
+ "match static addr: {2}",
+ cur_value, live_addr, static_addr.address);
+ return;
+ }
+
+ if (!process_sp->WritePointerToMemory(live_addr, dynamic_addr.address, error)) {
+ LLDB_LOG(log, "Got error: {0} writing dynamic value: {1} to {2}",
+ error, dynamic_addr.address, live_addr);
+ return;
+ }
+ }
+}
+
PersistentExpressionState::~PersistentExpressionState() = default;
lldb::addr_t PersistentExpressionState::LookupSymbol(ConstString name) {
diff --git a/lldb/source/Expression/LLVMUserExpression.cpp b/lldb/source/Expression/LLVMUserExpression.cpp
index 2d59194027b57..dac572e815fac 100644
--- a/lldb/source/Expression/LLVMUserExpression.cpp
+++ b/lldb/source/Expression/LLVMUserExpression.cpp
@@ -65,7 +65,7 @@ LLVMUserExpression::DoExecute(DiagnosticManager &diagnostic_manager,
ExecutionContext &exe_ctx,
const EvaluateExpressionOptions &options,
lldb::UserExpressionSP &shared_ptr_to_me,
- lldb::ExpressionVariableSP &result) {
+ lldb::ExpressionVariableSP &result_sp) {
// The expression log is quite verbose, and if you're just tracking the
// execution of the expression, it's quite convenient to have these logs come
// out with the STEP log as well.
@@ -250,8 +250,13 @@ LLVMUserExpression::DoExecute(DiagnosticManager &diagnostic_manager,
}
}
- if (FinalizeJITExecution(diagnostic_manager, exe_ctx, result,
+ if (FinalizeJITExecution(diagnostic_manager, exe_ctx, result_sp,
function_stack_bottom, function_stack_top)) {
+// if (result_sp) {
+// // This is a bit of a hack, replace with a real API. Trying to force
+// // fetching all the dynamic info at this point.
+// result_sp->GetValueObject();
+// }
return lldb::eExpressionCompleted;
}
@@ -289,8 +294,14 @@ bool LLVMUserExpression::FinalizeJITExecution(
result =
GetResultAfterDematerialization(exe_ctx.GetBestExecutionContextScope());
- if (result)
+ if (result) {
+ EvaluateExpressionOptions *options = GetOptions();
+ // TransferAddress also does the offset_to_top calculation, so record the
+ // dynamic option before we do that.
+ if (options)
+ result->PreserveDynamicOption(options->GetUseDynamic());
result->TransferAddress();
+ }
m_dematerializer_sp.reset();
diff --git a/lldb/source/Expression/Materializer.cpp b/lldb/source/Expression/Materializer.cpp
index 771a9ab84a20c..6561aff39217a 100644
--- a/lldb/source/Expression/Materializer.cpp
+++ b/lldb/source/Expression/Materializer.cpp
@@ -76,9 +76,9 @@ class EntityPersistentVariable : public Materializer::Entity {
const bool zero_memory = false;
IRMemoryMap::AllocationPolicy used_policy;
- auto address_or_error = map.Malloc(
- llvm::expectedToOptional(m_persistent_variable_sp->GetByteSize())
- .value_or(0),
+ uint64_t malloc_size = llvm::expectedToOptional(
+ m_persistent_variable_sp->GetByteSize()).value_or(0);
+ auto address_or_error = map.Malloc(malloc_size,
8, lldb::ePermissionsReadable | lldb::ePermissionsWritable,
IRMemoryMap::eAllocationPolicyMirror, zero_memory, &used_policy);
if (!address_or_error) {
@@ -90,7 +90,8 @@ class EntityPersistentVariable : public Materializer::Entity {
}
lldb::addr_t mem = *address_or_error;
- LLDB_LOGF(log, "Allocated %s (0x%" PRIx64 ") successfully",
+ LLDB_LOGF(log, "Allocated 0x%" PRIx64 "bytes for %s (0x%" PRIx64
+ ") successfully", malloc_size,
m_persistent_variable_sp->GetName().GetCString(), mem);
// Put the location of the spare memory into the live data of the
@@ -143,12 +144,14 @@ class EntityPersistentVariable : public Materializer::Entity {
void DestroyAllocation(IRMemoryMap &map, Status &err) {
Status deallocate_error;
- map.Free((lldb::addr_t)m_persistent_variable_sp->m_live_sp->GetValue()
+ lldb::ValueObjectSP live_valobj_sp
+ = m_persistent_variable_sp->GetLiveObject();
+ map.Free((lldb::addr_t)live_valobj_sp->GetValue()
.GetScalar()
.ULongLong(),
deallocate_error);
- m_persistent_variable_sp->m_live_sp.reset();
+ live_valobj_sp.reset();
if (!deallocate_error.Success()) {
err = Status::FromErrorStringWithFormat(
@@ -183,16 +186,17 @@ class EntityPersistentVariable : public Materializer::Entity {
return;
}
+ lldb::ValueObjectSP live_valobj_sp
+ = m_persistent_variable_sp->GetLiveObject();
if ((m_persistent_variable_sp->m_flags &
- ExpressionVariable::EVIsProgramReference &&
- m_persistent_variable_sp->m_live_sp) ||
+ ExpressionVariable::EVIsProgramReference && live_valobj_sp) ||
m_persistent_variable_sp->m_flags &
ExpressionVariable::EVIsLLDBAllocated) {
Status write_error;
map.WriteScalarToMemory(
load_addr,
- m_persistent_variable_sp->m_live_sp->GetValue().GetScalar(),
+ live_valobj_sp->GetValue().GetScalar(),
map.GetAddressByteSize(), write_error);
if (!write_error.Success()) {
@@ -229,18 +233,20 @@ class EntityPersistentVariable : public Materializer::Entity {
m_delegate->DidDematerialize(m_persistent_variable_sp);
}
+ lldb::ValueObjectSP live_valobj_sp
+ = m_persistent_variable_sp->GetLiveObject();
if ((m_persistent_variable_sp->m_flags &
ExpressionVariable::EVIsLLDBAllocated) ||
(m_persistent_variable_sp->m_flags &
ExpressionVariable::EVIsProgramReference)) {
if (m_persistent_variable_sp->m_flags &
ExpressionVariable::EVIsProgramReference &&
- !m_persistent_variable_sp->m_live_sp) {
+ !live_valobj_sp) {
// If the reference comes from the program, then the
// ClangExpressionVariable's live variable data hasn't been set up yet.
// Do this now.
- lldb::addr_t location;
+ lldb::addr_t location;
Status read_error;
map.ReadPointerFromMemory(&location, load_addr, read_error);
@@ -255,7 +261,7 @@ class EntityPersistentVariable : public Materializer::Entity {
m_persistent_variable_sp->m_live_sp = ValueObjectConstResult::Create(
map.GetBestExecutionContextScope(),
- m_persistent_variable_sp.get()->GetCompilerType(),
+ m_persistent_variable_sp->GetCompilerType(),
m_persistent_variable_sp->GetName(), location, eAddressTypeLoad,
llvm::expectedToOptional(m_persistent_variable_sp->GetByteSize())
.value_or(0));
@@ -277,19 +283,19 @@ class EntityPersistentVariable : public Materializer::Entity {
}
}
- lldb::addr_t mem = m_persistent_variable_sp->m_live_sp->GetValue()
- .GetScalar()
- .ULongLong();
-
- if (!m_persistent_variable_sp->m_live_sp) {
+ if (!live_valobj_sp) {
err = Status::FromErrorStringWithFormat(
"couldn't find the memory area used to store %s",
m_persistent_variable_sp->GetName().GetCString());
return;
}
- if (m_persistent_variable_sp->m_live_sp->GetValue()
- .GetValueAddressType() != eAddressTypeLoad) {
+ lldb::addr_t mem = live_valobj_sp->GetValue()
+ .GetScalar()
+ .ULongLong();
+
+ if (live_valobj_sp->GetValue().GetValueAddressType()
+ != eAddressTypeLoad) {
err = Status::FromErrorStringWithFormat(
"the address of the memory area for %s is in an incorrect format",
m_persistent_variable_sp->GetName().GetCString());
@@ -326,7 +332,6 @@ class EntityPersistentVariable : public Materializer::Entity {
read_error.AsCString());
return;
}
-
m_persistent_variable_sp->m_flags &=
~ExpressionVariable::EVNeedsFreezeDry;
}
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionVariable.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionVariable.cpp
index e2fb4a054daf3..d7b3fe0167299 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionVariable.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionVariable.cpp
@@ -59,6 +59,6 @@ ClangExpressionVariable::ClangExpressionVariable(
}
TypeFromUser ClangExpressionVariable::GetTypeFromUser() {
- TypeFromUser tfu(m_frozen_sp->GetCompilerType());
+ TypeFromUser tfu(GetValueObject()->GetCompilerType());
return tfu;
}
diff --git a/lldb/source/Target/ABI.cpp b/lldb/source/Target/ABI.cpp
index 3c51074340149..33bfa6b66fd06 100644
--- a/lldb/source/Target/ABI.cpp
+++ b/lldb/source/Target/ABI.cpp
@@ -136,7 +136,7 @@ ValueObjectSP ABI::GetReturnValueObject(Thread &thread, CompilerType &ast_type,
ExpressionVariable::EVNeedsAllocation;
break;
case Value::ValueType::LoadAddress:
- expr_variable_sp->m_live_sp = live_valobj_sp;
+ expr_variable_sp->GetLiveObject() = live_valobj_sp;
expr_variable_sp->m_flags |=
ExpressionVariable::EVIsProgramReference;
break;
diff --git a/lldb/test/API/functionalities/expr-result-var/Makefile b/lldb/test/API/functionalities/expr-result-var/Makefile
new file mode 100644
index 0000000000000..6c259307ef229
--- /dev/null
+++ b/lldb/test/API/functionalities/expr-result-var/Makefile
@@ -0,0 +1,3 @@
+CXX_SOURCES := two-bases.cpp
+
+include Makefile.rules
diff --git a/lldb/test/API/functionalities/expr-result-var/TestCPPExprResult.py b/lldb/test/API/functionalities/expr-result-var/TestCPPExprResult.py
new file mode 100644
index 0000000000000..020fdd341faaa
--- /dev/null
+++ b/lldb/test/API/functionalities/expr-result-var/TestCPPExprResult.py
@@ -0,0 +1,113 @@
+"""
+Test the reuse of C++ result variables, particularly making sure
+that the dynamic typing is preserved.
+"""
+
+
+
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class TestCPPResultVariables(TestBase):
+
+ NO_DEBUG_INFO_TESTCASE = True
+
+ def setUp(self):
+ TestBase.setUp(self)
+ self.main_source_file = lldb.SBFileSpec("two-bases.cpp")
+
+ def check_dereference(self, result_varname, frame, expr_options):
+ deref_expr = "*{0}".format(result_varname)
+ base_children = ValueCheck(name="Base", value="", children=[ValueCheck(name="base_int", value="100")])
+ base_1_arr_children= [ValueCheck(name="[0]", value="100"), ValueCheck(name="[1]", value="101"),
+ ValueCheck(name="[2]", value="102"), ValueCheck(name="[3]", value="103"),
+ ValueCheck(name="[4]", value="104"), ValueCheck(name="[5]", value="105"),
+ ValueCheck(name="[6]", value="106"), ValueCheck(name="[7]", value="107"),
+ ValueCheck(name="[8]", value="108"), ValueCheck(name="[9]", value="109")]
+ base_2_arr_children= [ValueCheck(name="[0]", value="200"), ValueCheck(name="[1]", value="201"),
+ ValueCheck(name="[2]", value="202"), ValueCheck(name="[3]", value="203"),
+ ValueCheck(name="...
[truncated]
|
|
✅ With the latest revision this PR passed the C/C++ code formatter. |
|
✅ With the latest revision this PR passed the Python code formatter. |
🐧 Linux x64 Test Results
|
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
When you run an expression and the result has a dynamic type that is different from the expression's static result type, we print the result variable using the dynamic type, but at present when you use the result variable in an expression later on, we only give you access to the static type. For instance:
The static return type of that function is
Base *, but we printed that the result was aDerived *and then only used theBase *part of it in subsequent expressions. That's not very helpful, and forces you to guess and then cast the result types to their dynamic type in order to be able to access the full type you were returned, which is inconvenient.This patch makes lldb retain the dynamic type of the result variable (and ditto for persistent result variables).
It also adds more testing of expression result variables with various types of dynamic values, to ensure we can access both the ivars and methods of the type we print the result as.