[LLDB] Optimize identifier lookup in DIL #146094
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@llvm/pr-subscribers-lldb Author: Ilia Kuklin (kuilpd) ChangesRemove unused code and unnecessary function calls, optimize global variable search. Full diff: https://github.com/llvm/llvm-project/pull/146094.diff 6 Files Affected:
diff --git a/lldb/include/lldb/ValueObject/DILEval.h b/lldb/include/lldb/ValueObject/DILEval.h
index 2a0cb548a810f..45e29b3ddcd7b 100644
--- a/lldb/include/lldb/ValueObject/DILEval.h
+++ b/lldb/include/lldb/ValueObject/DILEval.h
@@ -25,8 +25,7 @@ namespace lldb_private::dil {
/// evaluating).
lldb::ValueObjectSP LookupIdentifier(llvm::StringRef name_ref,
std::shared_ptr<StackFrame> frame_sp,
- lldb::DynamicValueType use_dynamic,
- CompilerType *scope_ptr = nullptr);
+ lldb::DynamicValueType use_dynamic);
/// Given the name of an identifier, check to see if it matches the name of a
/// global variable. If so, find the ValueObject for that global variable, and
@@ -35,8 +34,7 @@ lldb::ValueObjectSP LookupIdentifier(llvm::StringRef name_ref,
lldb::ValueObjectSP LookupGlobalIdentifier(llvm::StringRef name_ref,
std::shared_ptr<StackFrame> frame_sp,
lldb::TargetSP target_sp,
- lldb::DynamicValueType use_dynamic,
- CompilerType *scope_ptr = nullptr);
+ lldb::DynamicValueType use_dynamic);
class Interpreter : Visitor {
public:
diff --git a/lldb/source/ValueObject/DILEval.cpp b/lldb/source/ValueObject/DILEval.cpp
index b2bb4e20ddc24..f75f104ba2bc5 100644
--- a/lldb/source/ValueObject/DILEval.cpp
+++ b/lldb/source/ValueObject/DILEval.cpp
@@ -7,6 +7,7 @@
//===----------------------------------------------------------------------===//
#include "lldb/ValueObject/DILEval.h"
+#include "lldb/Symbol/CompileUnit.h"
#include "lldb/Symbol/VariableList.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/ValueObject/DILAST.h"
@@ -18,70 +19,26 @@
namespace lldb_private::dil {
-static lldb::ValueObjectSP LookupStaticIdentifier(
- VariableList &variable_list, std::shared_ptr<StackFrame> exe_scope,
- llvm::StringRef name_ref, llvm::StringRef unqualified_name) {
- // First look for an exact match to the (possibly) qualified name.
- for (const lldb::VariableSP &var_sp : variable_list) {
- lldb::ValueObjectSP valobj_sp(
- ValueObjectVariable::Create(exe_scope.get(), var_sp));
- if (valobj_sp && valobj_sp->GetVariable() &&
- (valobj_sp->GetVariable()->NameMatches(ConstString(name_ref))))
- return valobj_sp;
- }
-
- // If the qualified name is the same as the unqualfied name, there's nothing
- // more to be done.
- if (name_ref == unqualified_name)
- return nullptr;
-
- // We didn't match the qualified name; try to match the unqualified name.
- for (const lldb::VariableSP &var_sp : variable_list) {
- lldb::ValueObjectSP valobj_sp(
- ValueObjectVariable::Create(exe_scope.get(), var_sp));
- if (valobj_sp && valobj_sp->GetVariable() &&
- (valobj_sp->GetVariable()->NameMatches(ConstString(unqualified_name))))
- return valobj_sp;
- }
-
- return nullptr;
-}
-
static lldb::VariableSP DILFindVariable(ConstString name,
- lldb::VariableListSP variable_list) {
+ VariableList &variable_list) {
lldb::VariableSP exact_match;
std::vector<lldb::VariableSP> possible_matches;
- for (lldb::VariableSP var_sp : *variable_list) {
+ for (lldb::VariableSP var_sp : variable_list) {
llvm::StringRef str_ref_name = var_sp->GetName().GetStringRef();
- // Check for global vars, which might start with '::'.
- str_ref_name.consume_front("::");
- if (str_ref_name == name.GetStringRef())
- possible_matches.push_back(var_sp);
- else if (var_sp->NameMatches(name))
- possible_matches.push_back(var_sp);
- }
-
- // Look for exact matches (favors local vars over global vars)
- auto exact_match_it =
- llvm::find_if(possible_matches, [&](lldb::VariableSP var_sp) {
- return var_sp->GetName() == name;
- });
-
- if (exact_match_it != possible_matches.end())
- return *exact_match_it;
-
- // Look for a global var exact match.
- for (auto var_sp : possible_matches) {
- llvm::StringRef str_ref_name = var_sp->GetName().GetStringRef();
str_ref_name.consume_front("::");
+ // Check for the exact same match
if (str_ref_name == name.GetStringRef())
return var_sp;
+
+ // Check for possible matches by base name
+ if (var_sp->NameMatches(name))
+ possible_matches.push_back(var_sp);
}
- // If there's a single non-exact match, take it.
- if (possible_matches.size() == 1)
+ // If there's a non-exact match, take it.
+ if (possible_matches.size() > 0)
return possible_matches[0];
return nullptr;
@@ -89,38 +46,23 @@ static lldb::VariableSP DILFindVariable(ConstString name,
lldb::ValueObjectSP LookupGlobalIdentifier(
llvm::StringRef name_ref, std::shared_ptr<StackFrame> stack_frame,
- lldb::TargetSP target_sp, lldb::DynamicValueType use_dynamic,
- CompilerType *scope_ptr) {
- // First look for match in "local" global variables.
- lldb::VariableListSP variable_list(stack_frame->GetInScopeVariableList(true));
- name_ref.consume_front("::");
+ lldb::TargetSP target_sp, lldb::DynamicValueType use_dynamic) {
+ // Get a global variables list without the locals from the current frame
+ SymbolContext symbol_context =
+ stack_frame->GetSymbolContext(lldb::eSymbolContextCompUnit);
+ lldb::VariableListSP variable_list =
+ symbol_context.comp_unit->GetVariableList(true);
+ name_ref.consume_front("::");
lldb::ValueObjectSP value_sp;
if (variable_list) {
lldb::VariableSP var_sp =
- DILFindVariable(ConstString(name_ref), variable_list);
+ DILFindVariable(ConstString(name_ref), *variable_list);
if (var_sp)
value_sp =
stack_frame->GetValueObjectForFrameVariable(var_sp, use_dynamic);
}
- if (value_sp)
- return value_sp;
-
- // Also check for static global vars.
- if (variable_list) {
- const char *type_name = "";
- if (scope_ptr)
- type_name = scope_ptr->GetCanonicalType().GetTypeName().AsCString();
- std::string name_with_type_prefix =
- llvm::formatv("{0}::{1}", type_name, name_ref).str();
- value_sp = LookupStaticIdentifier(*variable_list, stack_frame,
- name_with_type_prefix, name_ref);
- if (!value_sp)
- value_sp = LookupStaticIdentifier(*variable_list, stack_frame, name_ref,
- name_ref);
- }
-
if (value_sp)
return value_sp;
@@ -129,28 +71,22 @@ lldb::ValueObjectSP LookupGlobalIdentifier(
target_sp->GetImages().FindGlobalVariables(
ConstString(name_ref), std::numeric_limits<uint32_t>::max(),
modules_var_list);
- if (modules_var_list.Empty())
- return nullptr;
- for (const lldb::VariableSP &var_sp : modules_var_list) {
- std::string qualified_name = llvm::formatv("::{0}", name_ref).str();
- if (var_sp->NameMatches(ConstString(name_ref)) ||
- var_sp->NameMatches(ConstString(qualified_name))) {
+ if (!modules_var_list.Empty()) {
+ lldb::VariableSP var_sp =
+ DILFindVariable(ConstString(name_ref), modules_var_list);
+ if (var_sp)
value_sp = ValueObjectVariable::Create(stack_frame.get(), var_sp);
- break;
- }
- }
-
- if (value_sp)
- return value_sp;
+ if (value_sp)
+ return value_sp;
+ }
return nullptr;
}
lldb::ValueObjectSP LookupIdentifier(llvm::StringRef name_ref,
std::shared_ptr<StackFrame> stack_frame,
- lldb::DynamicValueType use_dynamic,
- CompilerType *scope_ptr) {
+ lldb::DynamicValueType use_dynamic) {
// Support $rax as a special syntax for accessing registers.
// Will return an invalid value in case the requested register doesn't exist.
if (name_ref.consume_front("$")) {
@@ -164,38 +100,34 @@ lldb::ValueObjectSP LookupIdentifier(llvm::StringRef name_ref,
return nullptr;
}
- lldb::VariableListSP variable_list(
- stack_frame->GetInScopeVariableList(false));
-
if (!name_ref.contains("::")) {
- if (!scope_ptr || !scope_ptr->IsValid()) {
- // Lookup in the current frame.
- // Try looking for a local variable in current scope.
- lldb::ValueObjectSP value_sp;
- if (variable_list) {
- lldb::VariableSP var_sp =
- DILFindVariable(ConstString(name_ref), variable_list);
- if (var_sp)
- value_sp =
- stack_frame->GetValueObjectForFrameVariable(var_sp, use_dynamic);
- }
- if (!value_sp)
- value_sp = stack_frame->FindVariable(ConstString(name_ref));
-
- if (value_sp)
- return value_sp;
-
- // Try looking for an instance variable (class member).
- SymbolContext sc = stack_frame->GetSymbolContext(
- lldb::eSymbolContextFunction | lldb::eSymbolContextBlock);
- llvm::StringRef ivar_name = sc.GetInstanceVariableName();
- value_sp = stack_frame->FindVariable(ConstString(ivar_name));
- if (value_sp)
- value_sp = value_sp->GetChildMemberWithName(name_ref);
-
- if (value_sp)
- return value_sp;
+ // Lookup in the current frame.
+ // Try looking for a local variable in current scope.
+ lldb::VariableListSP variable_list(
+ stack_frame->GetInScopeVariableList(false));
+
+ lldb::ValueObjectSP value_sp;
+ if (variable_list) {
+ lldb::VariableSP var_sp =
+ variable_list->FindVariable(ConstString(name_ref));
+ if (var_sp)
+ value_sp =
+ stack_frame->GetValueObjectForFrameVariable(var_sp, use_dynamic);
}
+
+ if (value_sp)
+ return value_sp;
+
+ // Try looking for an instance variable (class member).
+ SymbolContext sc = stack_frame->GetSymbolContext(
+ lldb::eSymbolContextFunction | lldb::eSymbolContextBlock);
+ llvm::StringRef ivar_name = sc.GetInstanceVariableName();
+ value_sp = stack_frame->FindVariable(ConstString(ivar_name));
+ if (value_sp)
+ value_sp = value_sp->GetChildMemberWithName(name_ref);
+
+ if (value_sp)
+ return value_sp;
}
return nullptr;
}
diff --git a/lldb/test/API/commands/frame/var-dil/basics/GlobalVariableLookup/Makefile b/lldb/test/API/commands/frame/var-dil/basics/GlobalVariableLookup/Makefile
index 99998b20bcb05..c39bce9a94dcf 100644
--- a/lldb/test/API/commands/frame/var-dil/basics/GlobalVariableLookup/Makefile
+++ b/lldb/test/API/commands/frame/var-dil/basics/GlobalVariableLookup/Makefile
@@ -1,3 +1,3 @@
-CXX_SOURCES := main.cpp
+CXX_SOURCES := main.cpp extern.cpp
include Makefile.rules
diff --git a/lldb/test/API/commands/frame/var-dil/basics/GlobalVariableLookup/TestFrameVarDILGlobalVariableLookup.py b/lldb/test/API/commands/frame/var-dil/basics/GlobalVariableLookup/TestFrameVarDILGlobalVariableLookup.py
index edb013c7b3526..8a8f068c19466 100644
--- a/lldb/test/API/commands/frame/var-dil/basics/GlobalVariableLookup/TestFrameVarDILGlobalVariableLookup.py
+++ b/lldb/test/API/commands/frame/var-dil/basics/GlobalVariableLookup/TestFrameVarDILGlobalVariableLookup.py
@@ -32,20 +32,20 @@ def test_frame_var(self):
self.expect_var_path("::globalPtr", type="int *")
self.expect_var_path("::globalRef", type="int &")
- self.expect(
- "frame variable 'externGlobalVar'",
- error=True,
- substrs=["use of undeclared identifier"],
- ) # 0x00C0FFEE
- self.expect(
- "frame variable '::externGlobalVar'",
- error=True,
- substrs=["use of undeclared identifier"],
- ) # ["12648430"])
-
self.expect_var_path("ns::globalVar", value="13")
self.expect_var_path("ns::globalPtr", type="int *")
self.expect_var_path("ns::globalRef", type="int &")
self.expect_var_path("::ns::globalVar", value="13")
self.expect_var_path("::ns::globalPtr", type="int *")
self.expect_var_path("::ns::globalRef", type="int &")
+
+ self.expect_var_path("externGlobalVar", value="2")
+ self.expect_var_path("::externGlobalVar", value="2")
+ self.expect_var_path("ext::externGlobalVar", value="4")
+ self.expect_var_path("::ext::externGlobalVar", value="4")
+
+ self.expect_var_path("ExtStruct::static_inline", value="16")
+
+ # Test local variable priority over global
+ self.expect_var_path("foo", value="1")
+ self.expect_var_path("::foo", value="2")
diff --git a/lldb/test/API/commands/frame/var-dil/basics/GlobalVariableLookup/extern.cpp b/lldb/test/API/commands/frame/var-dil/basics/GlobalVariableLookup/extern.cpp
new file mode 100644
index 0000000000000..c451191dafc57
--- /dev/null
+++ b/lldb/test/API/commands/frame/var-dil/basics/GlobalVariableLookup/extern.cpp
@@ -0,0 +1,10 @@
+int externGlobalVar = 2;
+
+namespace ext {
+int externGlobalVar = 4;
+} // namespace ext
+
+struct ExtStruct {
+private:
+ static constexpr inline int static_inline = 16;
+} es;
diff --git a/lldb/test/API/commands/frame/var-dil/basics/GlobalVariableLookup/main.cpp b/lldb/test/API/commands/frame/var-dil/basics/GlobalVariableLookup/main.cpp
index 5bae4fd423e32..a8ecbe2d8fc44 100644
--- a/lldb/test/API/commands/frame/var-dil/basics/GlobalVariableLookup/main.cpp
+++ b/lldb/test/API/commands/frame/var-dil/basics/GlobalVariableLookup/main.cpp
@@ -10,6 +10,9 @@ int *globalPtr = &globalVar;
int &globalRef = globalVar;
} // namespace ns
+int foo = 2;
+
int main(int argc, char **argv) {
+ int foo = 1;
return 0; // Set a breakpoint here
}
|
|
I did some benchmarks of DIL on Unreal Engine 5 (thousands of variables to search through) and noticed that our current variable lookup implementation is ~10 times slower than it was in
Because of the extra search in the current file globals, DIL is now somewhat faster in searching variables in the current file and somewhat slower in searching variables in other files compared to |
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Remove unused code and unnecessary function calls, optimize global variable search.
Add more test cases.