JDevlieghere created this revision.
JDevlieghere added a reviewer: jingham.
Herald added a subscriber: pengfei.
JDevlieghere requested review of this revision.
LLDB uses utility functions to run code in the inferior for its own internal
purposes, such as reading classes from the Objective-C runtime for example.
Because these expressions should be transparent to the user, we ignore
breakpoints and unwind the stack on errors, which makes them hard to debug.
This patch adds a new setting `target.debug-utility-expression` that, when
enabled, changes these options to facilitate debugging. It enables breakpoints,
disables unwinding and writes out the utility function source code to disk.
Here's what this looks like in action. I added a nullptr dereference to
`__lldb_apple_objc_v2_get_shared_cache_class_info` and used
`TestDataFormatterObjCNSContainer` as an example:
$ lldb a.out
(lldb) target create "a.out"
Current executable set to 'a.out' (x86_64).
(lldb) b main.m:782
Breakpoint 1: where = a.out`main + 11752 at main.m:783:4, address =
0x0000000100006838
(lldb) setting set target.debug-utility-expression true
(lldb) r
Process 77039 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
frame #0: 0x0000000100006838 a.out`main(argc=1, argv=0x00007ffeefbff500)
at main.m:783:4
780 forKeyPath:@"atoms"
781 options:0
782 context:NULL]; // Set break point at this line.
-> 783 [newMutableDictionary addObserver:[My_KVO_Observer new]
784 forKeyPath:@"weirdKeyToKVO"
785 options:NSKeyValueObservingOptionNew
786 context:NULL];
Process 77039 launched: 'a.out' (x86_64)
(lldb) frame variable newArray nsDictionary newDictionary nscfDictionary
cfDictionaryRef newMutableDictionary newMutableDictionaryRef cfarray_ref
mutable_array_ref
warning: could not execute support code to read Objective-C class data in the
process. This may reduce the quality of type information available.
Process 77039 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS
(code=1, address=0x0)
frame #0: 0x00000001001df2de
__lldb_apple_objc_v2_get_shared_cache_class_info`__lldb_apple_objc_v2_get_shared_cache_class_info(objc_opt_ro_ptr=0x00007fff2031bc08,
class_infos_ptr=0x000000010063b000, class_infos_byte_size=1572864,
should_log=0) at lldb-9f30fe.expr:68
65 uint32_t
class_infos_byte_size,
66 uint32_t should_log)
67 {
-> 68 int *i = 0;
69 *i = 10;
70 uint32_t idx = 0;
71 DEBUG_PRINTF ("objc_opt_ro_ptr = %p\n", objc_opt_ro_ptr);
https://reviews.llvm.org/D97249
Files:
lldb/include/lldb/Expression/UtilityFunction.h
lldb/include/lldb/Symbol/TypeSystem.h
lldb/include/lldb/Target/Target.h
lldb/source/Expression/FunctionCaller.cpp
lldb/source/Expression/UtilityFunction.cpp
lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionSourceCode.cpp
lldb/source/Plugins/ExpressionParser/Clang/ClangUtilityFunction.cpp
lldb/source/Plugins/ExpressionParser/Clang/ClangUtilityFunction.h
lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp
lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.h
lldb/source/Symbol/TypeSystem.cpp
lldb/source/Target/Target.cpp
lldb/source/Target/TargetProperties.td
Index: lldb/source/Target/TargetProperties.td
===================================================================
--- lldb/source/Target/TargetProperties.td
+++ lldb/source/Target/TargetProperties.td
@@ -172,6 +172,9 @@
def AutoInstallMainExecutable: Property<"auto-install-main-executable", "Boolean">,
DefaultTrue,
Desc<"Always install the main executable when connected to a remote platform.">;
+ def DebugUtilityExpression: Property<"debug-utility-expression", "Boolean">,
+ DefaultFalse,
+ Desc<"Enable debugging of LLDB-internal utility expressions.">;
}
let Definition = "process_experimental" in {
Index: lldb/source/Target/Target.cpp
===================================================================
--- lldb/source/Target/Target.cpp
+++ lldb/source/Target/Target.cpp
@@ -2303,8 +2303,8 @@
return type_system_or_err.takeError();
std::unique_ptr<UtilityFunction> utility_fn =
- type_system_or_err->CreateUtilityFunction(std::move(expression),
- std::move(name));
+ type_system_or_err->CreateUtilityFunction(
+ std::move(expression), std::move(name), GetDebugUtilityExpression());
if (!utility_fn)
return llvm::make_error<llvm::StringError>(
llvm::StringRef("Could not create an expression for language") +
@@ -4307,6 +4307,17 @@
m_launch_info.GetFlags().Clear(lldb::eLaunchFlagDisableSTDIO);
}
+bool TargetProperties::GetDebugUtilityExpression() const {
+ const uint32_t idx = ePropertyDebugUtilityExpression;
+ return m_collection_sp->GetPropertyAtIndexAsBoolean(
+ nullptr, idx, g_target_properties[idx].default_uint_value != 0);
+}
+
+void TargetProperties::SetDebugUtilityExpression(bool debug) {
+ const uint32_t idx = ePropertyDebugUtilityExpression;
+ m_collection_sp->SetPropertyAtIndexAsBoolean(nullptr, idx, debug);
+}
+
// Target::TargetEventData
Target::TargetEventData::TargetEventData(const lldb::TargetSP &target_sp)
Index: lldb/source/Symbol/TypeSystem.cpp
===================================================================
--- lldb/source/Symbol/TypeSystem.cpp
+++ lldb/source/Symbol/TypeSystem.cpp
@@ -172,7 +172,8 @@
}
std::unique_ptr<UtilityFunction>
-TypeSystem::CreateUtilityFunction(std::string text, std::string name) {
+TypeSystem::CreateUtilityFunction(std::string text, std::string name,
+ bool debug) {
return {};
}
Index: lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.h
===================================================================
--- lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.h
+++ lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.h
@@ -1186,8 +1186,9 @@
const ValueList &arg_value_list,
const char *name) override;
- std::unique_ptr<UtilityFunction>
- CreateUtilityFunction(std::string text, std::string name) override;
+ std::unique_ptr<UtilityFunction> CreateUtilityFunction(std::string text,
+ std::string name,
+ bool debug) override;
PersistentExpressionState *GetPersistentExpressionState() override;
Index: lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
===================================================================
--- lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
+++ lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
@@ -9712,13 +9712,13 @@
std::unique_ptr<UtilityFunction>
ScratchTypeSystemClang::CreateUtilityFunction(std::string text,
- std::string name) {
+ std::string name, bool debug) {
TargetSP target_sp = m_target_wp.lock();
if (!target_sp)
return {};
return std::make_unique<ClangUtilityFunction>(
- *target_sp.get(), std::move(text), std::move(name));
+ *target_sp.get(), std::move(text), std::move(name), debug);
}
PersistentExpressionState *
Index: lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp
===================================================================
--- lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp
+++ lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp
@@ -172,7 +172,6 @@
// Testing using the new C++11 raw string literals. If this breaks GCC then we
// will need to revert to the code above...
static const char *g_get_shared_cache_class_info_body = R"(
-
extern "C"
{
size_t strlen(const char *);
@@ -1592,9 +1591,8 @@
if (objc_runtime) {
for (lldb::ModuleSP mod_sp : process->GetTarget().GetImages().Modules()) {
if (objc_runtime->IsModuleObjCLibrary(mod_sp)) {
- const Symbol *symbol =
- mod_sp->FindFirstSymbolWithNameAndType(g_class_getNameRaw_symbol_name,
- lldb::eSymbolTypeCode);
+ const Symbol *symbol = mod_sp->FindFirstSymbolWithNameAndType(
+ g_class_getNameRaw_symbol_name, lldb::eSymbolTypeCode);
if (symbol &&
(symbol->ValueIsAddress() || symbol->GetAddressRef().IsValid())) {
class_name_getter_function_name = g_class_getNameRaw_symbol_name;
Index: lldb/source/Plugins/ExpressionParser/Clang/ClangUtilityFunction.h
===================================================================
--- lldb/source/Plugins/ExpressionParser/Clang/ClangUtilityFunction.h
+++ lldb/source/Plugins/ExpressionParser/Clang/ClangUtilityFunction.h
@@ -49,7 +49,7 @@
/// \param[in] name
/// The name of the function, as used in the text.
ClangUtilityFunction(ExecutionContextScope &exe_scope, std::string text,
- std::string name);
+ std::string name, bool debug = false);
~ClangUtilityFunction() override;
Index: lldb/source/Plugins/ExpressionParser/Clang/ClangUtilityFunction.cpp
===================================================================
--- lldb/source/Plugins/ExpressionParser/Clang/ClangUtilityFunction.cpp
+++ lldb/source/Plugins/ExpressionParser/Clang/ClangUtilityFunction.cpp
@@ -42,11 +42,31 @@
/// \param[in] name
/// The name of the function, as used in the text.
ClangUtilityFunction::ClangUtilityFunction(ExecutionContextScope &exe_scope,
- std::string text, std::string name)
+ std::string text, std::string name,
+ bool debug)
: UtilityFunction(
exe_scope,
std::string(ClangExpressionSourceCode::g_expression_prefix) + text,
- std::move(name)) {}
+ std::move(name), debug) {
+ if (debug) {
+ int temp_fd = -1;
+ llvm::SmallString<128> result_path;
+ llvm::sys::fs::createTemporaryFile("lldb", "expr", temp_fd, result_path);
+ if (temp_fd != -1) {
+ lldb_private::NativeFile file(temp_fd, File::eOpenOptionWrite, true);
+ text = "#line 1 \"" + std::string(result_path) + "\"\n" + text;
+ size_t bytes_written = text.size();
+ file.Write(text.c_str(), bytes_written);
+ if (bytes_written == text.size()) {
+ // If we successfully wrote the source to a temporary file, replace the
+ // function text with the next text containing the line directive.
+ m_function_text =
+ std::string(ClangExpressionSourceCode::g_expression_prefix) + text;
+ }
+ file.Close();
+ }
+ }
+}
ClangUtilityFunction::~ClangUtilityFunction() {}
Index: lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionSourceCode.cpp
===================================================================
--- lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionSourceCode.cpp
+++ lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionSourceCode.cpp
@@ -35,7 +35,7 @@
const llvm::StringRef ClangExpressionSourceCode::g_prefix_file_name = PREFIX_NAME;
const char *ClangExpressionSourceCode::g_expression_prefix =
-"#line 1 \"" PREFIX_NAME R"("
+ "#line 1 \"" PREFIX_NAME R"("#line 1
#ifndef offsetof
#define offsetof(t, d) __builtin_offsetof(t, d)
#endif
Index: lldb/source/Expression/UtilityFunction.cpp
===================================================================
--- lldb/source/Expression/UtilityFunction.cpp
+++ lldb/source/Expression/UtilityFunction.cpp
@@ -41,7 +41,7 @@
/// \param[in] name
/// The name of the function, as used in the text.
UtilityFunction::UtilityFunction(ExecutionContextScope &exe_scope,
- std::string text, std::string name)
+ std::string text, std::string name, bool debug)
: Expression(exe_scope), m_execution_unit_sp(), m_jit_module_wp(),
m_function_text(std::move(text)), m_function_name(std::move(name)) {}
Index: lldb/source/Expression/FunctionCaller.cpp
===================================================================
--- lldb/source/Expression/FunctionCaller.cpp
+++ lldb/source/Expression/FunctionCaller.cpp
@@ -100,8 +100,7 @@
jit_file.GetFilename() = const_func_name;
jit_module_sp->SetFileSpecAndObjectName(jit_file, ConstString());
m_jit_module_wp = jit_module_sp;
- process->GetTarget().GetImages().Append(jit_module_sp,
- true /* notify */);
+ process->GetTarget().GetImages().Append(jit_module_sp, true /* notify */);
}
}
if (process && m_jit_start_addr)
@@ -317,12 +316,15 @@
lldb::ExpressionResults return_value = lldb::eExpressionSetupError;
// FunctionCaller::ExecuteFunction execution is always just to get the
- // result. Do make sure we ignore breakpoints, unwind on error, and don't try
- // to debug it.
+ // result. Unless explicitly asked for, ignore breakpoints and unwind on
+ // error.
+ const bool debug = exe_ctx.GetTargetPtr() &&
+ exe_ctx.GetTargetPtr()->GetDebugUtilityExpression();
EvaluateExpressionOptions real_options = options;
real_options.SetDebug(false);
- real_options.SetUnwindOnError(true);
- real_options.SetIgnoreBreakpoints(true);
+ real_options.SetGenerateDebugInfo(debug);
+ real_options.SetUnwindOnError(!debug);
+ real_options.SetIgnoreBreakpoints(!debug);
lldb::addr_t args_addr;
Index: lldb/include/lldb/Target/Target.h
===================================================================
--- lldb/include/lldb/Target/Target.h
+++ lldb/include/lldb/Target/Target.h
@@ -227,6 +227,10 @@
void UpdateLaunchInfoFromProperties();
+ void SetDebugUtilityExpression(bool debug);
+
+ bool GetDebugUtilityExpression() const;
+
private:
// Callbacks for m_launch_info.
void Arg0ValueChangedCallback();
Index: lldb/include/lldb/Symbol/TypeSystem.h
===================================================================
--- lldb/include/lldb/Symbol/TypeSystem.h
+++ lldb/include/lldb/Symbol/TypeSystem.h
@@ -470,7 +470,7 @@
}
virtual std::unique_ptr<UtilityFunction>
- CreateUtilityFunction(std::string text, std::string name);
+ CreateUtilityFunction(std::string text, std::string name, bool debug = false);
virtual PersistentExpressionState *GetPersistentExpressionState() {
return nullptr;
Index: lldb/include/lldb/Expression/UtilityFunction.h
===================================================================
--- lldb/include/lldb/Expression/UtilityFunction.h
+++ lldb/include/lldb/Expression/UtilityFunction.h
@@ -43,7 +43,7 @@
/// \param[in] name
/// The name of the function, as used in the text.
UtilityFunction(ExecutionContextScope &exe_scope, std::string text,
- std::string name);
+ std::string name, bool debug);
~UtilityFunction() override;
_______________________________________________
lldb-commits mailing list
lldb-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
