This is an archive of the discontinued LLVM Phabricator instance.

Paths

Table of Contentst

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lldb/trunk/
-
trunk/
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include/lldb/Expression/
-
lldb/
-
Expression/
-
DynamicCheckerFunctions.h
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IRDynamicChecks.h
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source/
-
Expression/
-
CMakeLists.txt
-
IRDynamicChecks.cpp
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Plugins/ExpressionParser/Clang/
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ExpressionParser/
-
Clang/
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CMakeLists.txt
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ClangExpressionParser.cpp
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IRDynamicChecks.h
-
IRDynamicChecks.cpp
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Target/
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Process.cpp
-
ThreadPlanCallUserExpression.cpp

Differential D64591

[Expression] Move IRDynamicChecks to ClangExpressionParser
ClosedPublic

Authored by xiaobai on Jul 11 2019, 1:47 PM.

Download Raw Diff

Details

Reviewers

compnerd
clayborg
jingham
JDevlieghere

Commits

rGbab7e3d78b01: [Expression] Move IRDynamicChecks to ClangExpressionParser
rL365853: [Expression] Move IRDynamicChecks to ClangExpressionParser
rLLDB365853: [Expression] Move IRDynamicChecks to ClangExpressionParser

Summary

IRDynamicChecks in its current form is specific to Clang since it deals
with the C language family. It is possible that we may want to
instrument code generated for other languages, but we can factor in a
more general mechanism to do so at a later time.

This decouples ObCLanguageRuntime from Expression!

Diff Detail

Repository: rL LLVM

Event Timeline

xiaobai created this revision.Jul 11 2019, 1:47 PM

Herald added a subscriber: mgorny. · View Herald TranscriptJul 11 2019, 1:47 PM

Harbormaster completed remote builds in B34805: Diff 209321.Jul 11 2019, 1:51 PM

JDevlieghere added inline comments.Jul 11 2019, 2:00 PM

include/lldb/Expression/DynamicCheckerFunctions.h
19 ↗	(On Diff #209321)	Can we skip this boilerplate?
27 ↗	(On Diff #209321)	Reflow comment.
source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp
1307 ↗	(On Diff #209321)	Spurious newline?

Reflow comment
Remove newline

Harbormaster completed remote builds in B34811: Diff 209335.Jul 11 2019, 2:23 PM

xiaobai added inline comments.Jul 11 2019, 2:23 PM

include/lldb/Expression/DynamicCheckerFunctions.h
19 ↗	(On Diff #209321)	Do you mean the whole thing? Or just the `\class` line?

JDevlieghere added inline comments.Jul 11 2019, 2:28 PM

include/lldb/Expression/DynamicCheckerFunctions.h
19 ↗	(On Diff #209321)	Everything up to "Encapsulates dynamic check...", Doxygen is smart enough to associate the comment with the class.

Remove documentation boilerplate

Harbormaster completed remote builds in B34812: Diff 209351.Jul 11 2019, 3:04 PM

This is a little unclear to me. LLVMUserExpression is the class that represents "anything that uses LLVM at its back end." Both the Swift & Clang user expressions are instances of this. Running through IR and inserting little callouts is an LLVMUserExpression type thing. So it seems like this move is in the right direction, but to be really clean needs to represent LLVMUserExpression in the Plugin Hierarchy.

xiaobai mentioned this in D64599: [LanguageRuntime] Move CPPLanguageRuntime into a plugin.Jul 11 2019, 3:49 PM

In D64591#1581775, @jingham wrote:

This is a little unclear to me. LLVMUserExpression is the class that represents "anything that uses LLVM at its back end." Both the Swift & Clang user expressions are instances of this. Running through IR and inserting little callouts is an LLVMUserExpression type thing. So it seems like this move is in the right direction, but to be really clean needs to represent LLVMUserExpression in the Plugin Hierarchy.

Right, this makes sense to me. My understanding was that LLVMUserExpression would eventually invoke ClangExpressionParser, which actually handles dealing with IR instrumentation. With swift in the picture, things get a little more complicated because you could want to deal with both ObjC code and Swift code. I think that in that case, LLDB would want to use both Clang and Swift to instrument a user expression. I don't think that the abstractions are set up to account for this use case right now, so it would require some planning and refactoring.

Then the IRDynamicCheck part would go with LLVMUserExpression, and the C-specific checks in Clang...

In D64591#1581820, @jingham wrote:

Then the IRDynamicCheck part would go with LLVMUserExpression, and the C-specific checks in Clang...

Except IRDynamicChecks has special knowledge of the clang-specific instrumenters. I can think of another way in which DynamicCheckerFunctions and IRDynamicChecks are more generic classes that will work with any language. I can try to explore that option to see what I come up with, maybe the end result will be better?

That would be cleaner.

OTOH, the original reason for these checkers was to help people understand crashes in their expressions more clearly. Supposedly, modern languages "don't have pointers" and can't have bad objects, so the kind of crashes this instrumentation was supposed to help with "can't happen" and checkers for such languages wouldn't be all that helpful...

So while cleaner, maybe generalizing this more fully isn't a high priority change? In which case, just getting them out of generic code seems fine as a stopping point. Your choice.

This revision is now accepted and ready to land.Jul 11 2019, 4:17 PM

In D64591#1581878, @jingham wrote:

That would be cleaner.

OTOH, the original reason for these checkers was to help people understand crashes in their expressions more clearly. Supposedly, modern languages "don't have pointers" and can't have bad objects, so the kind of crashes this instrumentation was supposed to help with "can't happen" and checkers for such languages wouldn't be all that helpful...

So while cleaner, maybe generalizing this more fully isn't a high priority change? In which case, just getting them out of generic code seems fine as a stopping point. Your choice.

I don't think of it as high priority. That might change at some in the future, but for the time being I think that there are bigger fish to fry.

Closed by commit rL365853: [Expression] Move IRDynamicChecks to ClangExpressionParser (authored by xiaobai). · Explain WhyJul 11 2019, 5:58 PM

This revision was automatically updated to reflect the committed changes.

Herald added a project: Restricted Project. · View Herald TranscriptJul 11 2019, 5:58 PM

Herald added a subscriber: llvm-commits. · View Herald Transcript

Revision Contents

Path

Size

lldb/

trunk/

include/

lldb/

Expression/

DynamicCheckerFunctions.h

62 lines

IRDynamicChecks.h

145 lines

source/

Expression/

CMakeLists.txt

1 line

IRDynamicChecks.cpp

593 lines

Plugins/

ExpressionParser/

Clang/

CMakeLists.txt

1 line

ClangExpressionParser.cpp

39 lines

IRDynamicChecks.h

131 lines

IRDynamicChecks.cpp

594 lines

Target/

Process.cpp

2 lines

ThreadPlanCallUserExpression.cpp

2 lines

Diff 209388

lldb/trunk/include/lldb/Expression/DynamicCheckerFunctions.h

				//===-- DynamicCheckerFunctions.h -------------------------------- C++ --===//
				//
				// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
				// See https://llvm.org/LICENSE.txt for license information.
				// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
				//
				//===----------------------------------------------------------------------===//

				#ifndef liblldb_DynamicCheckerFunctions_h_
				#define liblldb_DynamicCheckerFunctions_h_

				#include "lldb/lldb-types.h"

				namespace lldb_private {

				class DiagnosticManager;
				class ExecutionContext;

				/// Encapsulates dynamic check functions used by expressions.
				///
				/// Each of the utility functions encapsulated in this class is responsible
				/// for validating some data that an expression is about to use. Examples
				/// are:
				///
				/// a = *b; // check that b is a valid pointer
				/// [b init]; // check that b is a valid object to send "init" to
				///
				/// The class installs each checker function into the target process and makes
				/// it available to IRDynamicChecks to use.
				class DynamicCheckerFunctions {
				public:
				enum DynamicCheckerFunctionsKind {
				DCF_Clang,
				};

				DynamicCheckerFunctions(DynamicCheckerFunctionsKind kind) : m_kind(kind) {}
				virtual ~DynamicCheckerFunctions() = default;

				/// Install the utility functions into a process. This binds the instance
				/// of DynamicCheckerFunctions to that process.
				///
				/// \param[in] diagnostic_manager
				/// A diagnostic manager to report errors to.
				///
				/// \param[in] exe_ctx
				/// The execution context to install the functions into.
				///
				/// \return
				/// True on success; false on failure, or if the functions have
				/// already been installed.
				virtual bool Install(DiagnosticManager &diagnostic_manager,
				ExecutionContext &exe_ctx) = 0;
				virtual bool DoCheckersExplainStop(lldb::addr_t addr, Stream &message) = 0;

				DynamicCheckerFunctionsKind GetKind() const { return m_kind; }

				private:
				const DynamicCheckerFunctionsKind m_kind;
				};
				} // namespace lldb_private

				#endif // liblldb_DynamicCheckerFunctions_h_

lldb/trunk/include/lldb/Expression/IRDynamicChecks.h

	//===-- IRDynamicChecks.h ---------------------------------------- C++ --===//
	//
	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
	// See https://llvm.org/LICENSE.txt for license information.
	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
	//
	//===----------------------------------------------------------------------===//

	#ifndef liblldb_IRDynamicChecks_h_
	#define liblldb_IRDynamicChecks_h_

	#include "lldb/lldb-types.h"
	#include "llvm/Pass.h"

	namespace llvm {
	class BasicBlock;
	class CallInst;
	class Constant;
	class Function;
	class Instruction;
	class Module;
	class DataLayout;
	class Value;
	}

	namespace lldb_private {

	class ClangExpressionDeclMap;
	class ExecutionContext;
	class Stream;

	/// \class DynamicCheckerFunctions IRDynamicChecks.h
	/// "lldb/Expression/IRDynamicChecks.h" Encapsulates dynamic check functions
	/// used by expressions.
	///
	/// Each of the utility functions encapsulated in this class is responsible
	/// for validating some data that an expression is about to use. Examples
	/// are:
	///
	/// a = *b; // check that b is a valid pointer [b init]; // check that b
	/// is a valid object to send "init" to
	///
	/// The class installs each checker function into the target process and makes
	/// it available to IRDynamicChecks to use.
	class DynamicCheckerFunctions {
	public:
	/// Constructor
	DynamicCheckerFunctions();

	/// Destructor
	~DynamicCheckerFunctions();

	/// Install the utility functions into a process. This binds the instance
	/// of DynamicCheckerFunctions to that process.
	///
	/// \param[in] diagnostic_manager
	/// A diagnostic manager to report errors to.
	///
	/// \param[in] exe_ctx
	/// The execution context to install the functions into.
	///
	/// \return
	/// True on success; false on failure, or if the functions have
	/// already been installed.
	bool Install(DiagnosticManager &diagnostic_manager,
	ExecutionContext &exe_ctx);

	bool DoCheckersExplainStop(lldb::addr_t addr, Stream &message);

	std::shared_ptr<UtilityFunction> m_valid_pointer_check;
	std::shared_ptr<UtilityFunction> m_objc_object_check;
	};

	/// \class IRDynamicChecks IRDynamicChecks.h
	/// "lldb/Expression/IRDynamicChecks.h" Adds dynamic checks to a user-entered
	/// expression to reduce its likelihood of crashing
	///
	/// When an IR function is executed in the target process, it may cause
	/// crashes or hangs by dereferencing NULL pointers, trying to call
	/// Objective-C methods on objects that do not respond to them, and so forth.
	///
	/// IRDynamicChecks adds calls to the functions in DynamicCheckerFunctions to
	/// appropriate locations in an expression's IR.
	class IRDynamicChecks : public llvm::ModulePass {
	public:
	/// Constructor
	///
	/// \param[in] checker_functions
	/// The checker functions for the target process.
	///
	/// \param[in] func_name
	/// The name of the function to prepare for execution in the target.
	///
	/// \param[in] decl_map
	/// The mapping used to look up entities in the target process. In
	/// this case, used to find objc_msgSend
	IRDynamicChecks(DynamicCheckerFunctions &checker_functions,
	const char *func_name = "$__lldb_expr");

	/// Destructor
	~IRDynamicChecks() override;

	/// Run this IR transformer on a single module
	///
	/// \param[in] M
	/// The module to run on. This module is searched for the function
	/// $__lldb_expr, and that function is passed to the passes one by
	/// one.
	///
	/// \return
	/// True on success; false otherwise
	bool runOnModule(llvm::Module &M) override;

	/// Interface stub
	void assignPassManager(
	llvm::PMStack &PMS,
	llvm::PassManagerType T = llvm::PMT_ModulePassManager) override;

	/// Returns PMT_ModulePassManager
	llvm::PassManagerType getPotentialPassManagerType() const override;

	private:
	/// A basic block-level pass to find all pointer dereferences and
	/// validate them before use.

	/// The top-level pass implementation
	///
	/// \param[in] M
	/// The module currently being processed.
	///
	/// \param[in] BB
	/// The basic block currently being processed.
	///
	/// \return
	/// True on success; false otherwise
	bool FindDataLoads(llvm::Module &M, llvm::BasicBlock &BB);

	std::string m_func_name; ///< The name of the function to add checks to
	DynamicCheckerFunctions
	&m_checker_functions; ///< The checker functions for the process
	};

	} // namespace lldb_private

	#endif // liblldb_IRDynamicChecks_h_

lldb/trunk/source/Expression/CMakeLists.txt

	if(NOT LLDB_BUILT_STANDALONE)			if(NOT LLDB_BUILT_STANDALONE)
	set(tablegen_deps intrinsics_gen)			set(tablegen_deps intrinsics_gen)
	endif()			endif()

	add_lldb_library(lldbExpression			add_lldb_library(lldbExpression
	DiagnosticManager.cpp			DiagnosticManager.cpp
	DWARFExpression.cpp			DWARFExpression.cpp
	Expression.cpp			Expression.cpp
	ExpressionVariable.cpp			ExpressionVariable.cpp
	FunctionCaller.cpp			FunctionCaller.cpp
	IRDynamicChecks.cpp
	IRExecutionUnit.cpp			IRExecutionUnit.cpp
	IRInterpreter.cpp			IRInterpreter.cpp
	IRMemoryMap.cpp			IRMemoryMap.cpp
	LLVMUserExpression.cpp			LLVMUserExpression.cpp
	Materializer.cpp			Materializer.cpp
	REPL.cpp			REPL.cpp
	UserExpression.cpp			UserExpression.cpp
	UtilityFunction.cpp			UtilityFunction.cpp
	Show All 19 Lines

lldb/trunk/source/Expression/IRDynamicChecks.cpp

	//===-- IRDynamicChecks.cpp -------------------------------------- C++ --===//
	//
	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
	// See https://llvm.org/LICENSE.txt for license information.
	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
	//
	//===----------------------------------------------------------------------===//

	#include "llvm/IR/Constants.h"
	#include "llvm/IR/DataLayout.h"
	#include "llvm/IR/Function.h"
	#include "llvm/IR/Instructions.h"
	#include "llvm/IR/Module.h"
	#include "llvm/IR/Value.h"
	#include "llvm/Support/raw_ostream.h"

	#include "lldb/Expression/IRDynamicChecks.h"

	#include "lldb/Expression/UtilityFunction.h"
	#include "lldb/Target/ExecutionContext.h"
	#include "lldb/Target/ObjCLanguageRuntime.h"
	#include "lldb/Target/Process.h"
	#include "lldb/Target/StackFrame.h"
	#include "lldb/Target/Target.h"
	#include "lldb/Utility/ConstString.h"
	#include "lldb/Utility/Log.h"

	using namespace llvm;
	using namespace lldb_private;

	static char ID;

	#define VALID_POINTER_CHECK_NAME "_$__lldb_valid_pointer_check"
	#define VALID_OBJC_OBJECT_CHECK_NAME "$__lldb_objc_object_check"

	static const char g_valid_pointer_check_text[] =
	"extern \"C\" void\n"
	"_$__lldb_valid_pointer_check (unsigned char *$__lldb_arg_ptr)\n"
	"{\n"
	" unsigned char $__lldb_local_val = *$__lldb_arg_ptr;\n"
	"}";

	DynamicCheckerFunctions::DynamicCheckerFunctions() = default;

	DynamicCheckerFunctions::~DynamicCheckerFunctions() = default;

	bool DynamicCheckerFunctions::Install(DiagnosticManager &diagnostic_manager,
	ExecutionContext &exe_ctx) {
	Status error;
	m_valid_pointer_check.reset(
	exe_ctx.GetTargetRef().GetUtilityFunctionForLanguage(
	g_valid_pointer_check_text, lldb::eLanguageTypeC,
	VALID_POINTER_CHECK_NAME, error));
	if (error.Fail())
	return false;

	if (!m_valid_pointer_check->Install(diagnostic_manager, exe_ctx))
	return false;

	Process *process = exe_ctx.GetProcessPtr();

	if (process) {
	ObjCLanguageRuntime *objc_language_runtime =
	ObjCLanguageRuntime::Get(*process);

	if (objc_language_runtime) {
	m_objc_object_check.reset(objc_language_runtime->CreateObjectChecker(
	VALID_OBJC_OBJECT_CHECK_NAME));

	if (!m_objc_object_check->Install(diagnostic_manager, exe_ctx))
	return false;
	}
	}

	return true;
	}

	bool DynamicCheckerFunctions::DoCheckersExplainStop(lldb::addr_t addr,
	Stream &message) {
	// FIXME: We have to get the checkers to know why they scotched the call in
	// more detail,
	// so we can print a better message here.
	if (m_valid_pointer_check && m_valid_pointer_check->ContainsAddress(addr)) {
	message.Printf("Attempted to dereference an invalid pointer.");
	return true;
	} else if (m_objc_object_check &&
	m_objc_object_check->ContainsAddress(addr)) {
	message.Printf("Attempted to dereference an invalid ObjC Object or send it "
	"an unrecognized selector");
	return true;
	}
	return false;
	}

	static std::string PrintValue(llvm::Value *V, bool truncate = false) {
	std::string s;
	raw_string_ostream rso(s);
	V->print(rso);
	rso.flush();
	if (truncate)
	s.resize(s.length() - 1);
	return s;
	}

	/// \class Instrumenter IRDynamicChecks.cpp
	/// Finds and instruments individual LLVM IR instructions
	///
	/// When instrumenting LLVM IR, it is frequently desirable to first search for
	/// instructions, and then later modify them. This way iterators remain
	/// intact, and multiple passes can look at the same code base without
	/// treading on each other's toes.
	///
	/// The Instrumenter class implements this functionality. A client first
	/// calls Inspect on a function, which populates a list of instructions to be
	/// instrumented. Then, later, when all passes' Inspect functions have been
	/// called, the client calls Instrument, which adds the desired
	/// instrumentation.
	///
	/// A subclass of Instrumenter must override InstrumentInstruction, which
	/// is responsible for adding whatever instrumentation is necessary.
	///
	/// A subclass of Instrumenter may override:
	///
	/// - InspectInstruction [default: does nothing]
	///
	/// - InspectBasicBlock [default: iterates through the instructions in a
	/// basic block calling InspectInstruction]
	///
	/// - InspectFunction [default: iterates through the basic blocks in a
	/// function calling InspectBasicBlock]
	class Instrumenter {
	public:
	/// Constructor
	///
	/// \param[in] module
	/// The module being instrumented.
	Instrumenter(llvm::Module &module,
	std::shared_ptr<UtilityFunction> checker_function)
	: m_module(module), m_checker_function(checker_function),
	m_i8ptr_ty(nullptr), m_intptr_ty(nullptr) {}

	virtual ~Instrumenter() = default;

	/// Inspect a function to find instructions to instrument
	///
	/// \param[in] function
	/// The function to inspect.
	///
	/// \return
	/// True on success; false on error.
	bool Inspect(llvm::Function &function) { return InspectFunction(function); }

	/// Instrument all the instructions found by Inspect()
	///
	/// \return
	/// True on success; false on error.
	bool Instrument() {
	for (InstIterator ii = m_to_instrument.begin(),
	last_ii = m_to_instrument.end();
	ii != last_ii; ++ii) {
	if (!InstrumentInstruction(*ii))
	return false;
	}

	return true;
	}

	protected:
	/// Add instrumentation to a single instruction
	///
	/// \param[in] inst
	/// The instruction to be instrumented.
	///
	/// \return
	/// True on success; false otherwise.
	virtual bool InstrumentInstruction(llvm::Instruction *inst) = 0;

	/// Register a single instruction to be instrumented
	///
	/// \param[in] inst
	/// The instruction to be instrumented.
	void RegisterInstruction(llvm::Instruction &i) {
	m_to_instrument.push_back(&i);
	}

	/// Determine whether a single instruction is interesting to instrument,
	/// and, if so, call RegisterInstruction
	///
	/// \param[in] i
	/// The instruction to be inspected.
	///
	/// \return
	/// False if there was an error scanning; true otherwise.
	virtual bool InspectInstruction(llvm::Instruction &i) { return true; }

	/// Scan a basic block to see if any instructions are interesting
	///
	/// \param[in] bb
	/// The basic block to be inspected.
	///
	/// \return
	/// False if there was an error scanning; true otherwise.
	virtual bool InspectBasicBlock(llvm::BasicBlock &bb) {
	for (llvm::BasicBlock::iterator ii = bb.begin(), last_ii = bb.end();
	ii != last_ii; ++ii) {
	if (!InspectInstruction(*ii))
	return false;
	}

	return true;
	}

	/// Scan a function to see if any instructions are interesting
	///
	/// \param[in] f
	/// The function to be inspected.
	///
	/// \return
	/// False if there was an error scanning; true otherwise.
	virtual bool InspectFunction(llvm::Function &f) {
	for (llvm::Function::iterator bbi = f.begin(), last_bbi = f.end();
	bbi != last_bbi; ++bbi) {
	if (!InspectBasicBlock(*bbi))
	return false;
	}

	return true;
	}

	/// Build a function pointer for a function with signature void
	/// ()(uint8_t) with a given address
	///
	/// \param[in] start_address
	/// The address of the function.
	///
	/// \return
	/// The function pointer, for use in a CallInst.
	llvm::FunctionCallee BuildPointerValidatorFunc(lldb::addr_t start_address) {
	llvm::Type *param_array[1];

	param_array[0] = const_cast<llvm::PointerType *>(GetI8PtrTy());

	ArrayRef<llvm::Type *> params(param_array, 1);

	FunctionType *fun_ty = FunctionType::get(
	llvm::Type::getVoidTy(m_module.getContext()), params, true);
	PointerType *fun_ptr_ty = PointerType::getUnqual(fun_ty);
	Constant *fun_addr_int =
	ConstantInt::get(GetIntptrTy(), start_address, false);
	return {fun_ty, ConstantExpr::getIntToPtr(fun_addr_int, fun_ptr_ty)};
	}

	/// Build a function pointer for a function with signature void
	/// ()(uint8_t, uint8_t*) with a given address
	///
	/// \param[in] start_address
	/// The address of the function.
	///
	/// \return
	/// The function pointer, for use in a CallInst.
	llvm::FunctionCallee BuildObjectCheckerFunc(lldb::addr_t start_address) {
	llvm::Type *param_array[2];

	param_array[0] = const_cast<llvm::PointerType *>(GetI8PtrTy());
	param_array[1] = const_cast<llvm::PointerType *>(GetI8PtrTy());

	ArrayRef<llvm::Type *> params(param_array, 2);

	FunctionType *fun_ty = FunctionType::get(
	llvm::Type::getVoidTy(m_module.getContext()), params, true);
	PointerType *fun_ptr_ty = PointerType::getUnqual(fun_ty);
	Constant *fun_addr_int =
	ConstantInt::get(GetIntptrTy(), start_address, false);
	return {fun_ty, ConstantExpr::getIntToPtr(fun_addr_int, fun_ptr_ty)};
	}

	PointerType *GetI8PtrTy() {
	if (!m_i8ptr_ty)
	m_i8ptr_ty = llvm::Type::getInt8PtrTy(m_module.getContext());

	return m_i8ptr_ty;
	}

	IntegerType *GetIntptrTy() {
	if (!m_intptr_ty) {
	llvm::DataLayout data_layout(&m_module);

	m_intptr_ty = llvm::Type::getIntNTy(m_module.getContext(),
	data_layout.getPointerSizeInBits());
	}

	return m_intptr_ty;
	}

	typedef std::vector<llvm::Instruction *> InstVector;
	typedef InstVector::iterator InstIterator;

	InstVector m_to_instrument; ///< List of instructions the inspector found
	llvm::Module &m_module; ///< The module which is being instrumented
	std::shared_ptr<UtilityFunction>
	m_checker_function; ///< The dynamic checker function for the process

	private:
	PointerType *m_i8ptr_ty;
	IntegerType *m_intptr_ty;
	};

	class ValidPointerChecker : public Instrumenter {
	public:
	ValidPointerChecker(llvm::Module &module,
	std::shared_ptr<UtilityFunction> checker_function)
	: Instrumenter(module, checker_function),
	m_valid_pointer_check_func(nullptr) {}

	~ValidPointerChecker() override = default;

	protected:
	bool InstrumentInstruction(llvm::Instruction *inst) override {
	Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));

	if (log)
	log->Printf("Instrumenting load/store instruction: %s\n",
	PrintValue(inst).c_str());

	if (!m_valid_pointer_check_func)
	m_valid_pointer_check_func =
	BuildPointerValidatorFunc(m_checker_function->StartAddress());

	llvm::Value *dereferenced_ptr = nullptr;

	if (llvm::LoadInst *li = dyn_cast<llvm::LoadInst>(inst))
	dereferenced_ptr = li->getPointerOperand();
	else if (llvm::StoreInst *si = dyn_cast<llvm::StoreInst>(inst))
	dereferenced_ptr = si->getPointerOperand();
	else
	return false;

	// Insert an instruction to cast the loaded value to int8_t*

	BitCastInst *bit_cast =
	new BitCastInst(dereferenced_ptr, GetI8PtrTy(), "", inst);

	// Insert an instruction to call the helper with the result

	llvm::Value *arg_array[1];

	arg_array[0] = bit_cast;

	llvm::ArrayRef<llvm::Value *> args(arg_array, 1);

	CallInst::Create(m_valid_pointer_check_func, args, "", inst);

	return true;
	}

	bool InspectInstruction(llvm::Instruction &i) override {
	if (dyn_cast<llvm::LoadInst>(&i) \|\| dyn_cast<llvm::StoreInst>(&i))
	RegisterInstruction(i);

	return true;
	}

	private:
	llvm::FunctionCallee m_valid_pointer_check_func;
	};

	class ObjcObjectChecker : public Instrumenter {
	public:
	ObjcObjectChecker(llvm::Module &module,
	std::shared_ptr<UtilityFunction> checker_function)
	: Instrumenter(module, checker_function),
	m_objc_object_check_func(nullptr) {}

	~ObjcObjectChecker() override = default;

	enum msgSend_type {
	eMsgSend = 0,
	eMsgSendSuper,
	eMsgSendSuper_stret,
	eMsgSend_fpret,
	eMsgSend_stret
	};

	std::map<llvm::Instruction *, msgSend_type> msgSend_types;

	protected:
	bool InstrumentInstruction(llvm::Instruction *inst) override {
	CallInst *call_inst = dyn_cast<CallInst>(inst);

	if (!call_inst)
	return false; // call_inst really shouldn't be nullptr, because otherwise
	// InspectInstruction wouldn't have registered it

	if (!m_objc_object_check_func)
	m_objc_object_check_func =
	BuildObjectCheckerFunc(m_checker_function->StartAddress());

	// id objc_msgSend(id theReceiver, SEL theSelector, ...)

	llvm::Value *target_object;
	llvm::Value *selector;

	switch (msgSend_types[inst]) {
	case eMsgSend:
	case eMsgSend_fpret:
	// On arm64, clang uses objc_msgSend for scalar and struct return
	// calls. The call instruction will record which was used.
	if (call_inst->hasStructRetAttr()) {
	target_object = call_inst->getArgOperand(1);
	selector = call_inst->getArgOperand(2);
	} else {
	target_object = call_inst->getArgOperand(0);
	selector = call_inst->getArgOperand(1);
	}
	break;
	case eMsgSend_stret:
	target_object = call_inst->getArgOperand(1);
	selector = call_inst->getArgOperand(2);
	break;
	case eMsgSendSuper:
	case eMsgSendSuper_stret:
	return true;
	}

	// These objects should always be valid according to Sean Calannan
	assert(target_object);
	assert(selector);

	// Insert an instruction to cast the receiver id to int8_t*

	BitCastInst *bit_cast =
	new BitCastInst(target_object, GetI8PtrTy(), "", inst);

	// Insert an instruction to call the helper with the result

	llvm::Value *arg_array[2];

	arg_array[0] = bit_cast;
	arg_array[1] = selector;

	ArrayRef<llvm::Value *> args(arg_array, 2);

	CallInst::Create(m_objc_object_check_func, args, "", inst);

	return true;
	}

	static llvm::Function GetFunction(llvm::Value value) {
	if (llvm::Function *function = llvm::dyn_cast<llvm::Function>(value)) {
	return function;
	}

	if (llvm::ConstantExpr *const_expr =
	llvm::dyn_cast<llvm::ConstantExpr>(value)) {
	switch (const_expr->getOpcode()) {
	default:
	return nullptr;
	case llvm::Instruction::BitCast:
	return GetFunction(const_expr->getOperand(0));
	}
	}

	return nullptr;
	}

	static llvm::Function GetCalledFunction(llvm::CallInst inst) {
	return GetFunction(inst->getCalledValue());
	}

	bool InspectInstruction(llvm::Instruction &i) override {
	Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));

	CallInst *call_inst = dyn_cast<CallInst>(&i);

	if (call_inst) {
	const llvm::Function *called_function = GetCalledFunction(call_inst);

	if (!called_function)
	return true;

	std::string name_str = called_function->getName().str();
	const char *name_cstr = name_str.c_str();

	if (log)
	log->Printf("Found call to %s: %s\n", name_cstr,
	PrintValue(call_inst).c_str());

	if (name_str.find("objc_msgSend") == std::string::npos)
	return true;

	if (!strcmp(name_cstr, "objc_msgSend")) {
	RegisterInstruction(i);
	msgSend_types[&i] = eMsgSend;
	return true;
	}

	if (!strcmp(name_cstr, "objc_msgSend_stret")) {
	RegisterInstruction(i);
	msgSend_types[&i] = eMsgSend_stret;
	return true;
	}

	if (!strcmp(name_cstr, "objc_msgSend_fpret")) {
	RegisterInstruction(i);
	msgSend_types[&i] = eMsgSend_fpret;
	return true;
	}

	if (!strcmp(name_cstr, "objc_msgSendSuper")) {
	RegisterInstruction(i);
	msgSend_types[&i] = eMsgSendSuper;
	return true;
	}

	if (!strcmp(name_cstr, "objc_msgSendSuper_stret")) {
	RegisterInstruction(i);
	msgSend_types[&i] = eMsgSendSuper_stret;
	return true;
	}

	if (log)
	log->Printf(
	"Function name '%s' contains 'objc_msgSend' but is not handled",
	name_str.c_str());

	return true;
	}

	return true;
	}

	private:
	llvm::FunctionCallee m_objc_object_check_func;
	};

	IRDynamicChecks::IRDynamicChecks(DynamicCheckerFunctions &checker_functions,
	const char *func_name)
	: ModulePass(ID), m_func_name(func_name),
	m_checker_functions(checker_functions) {}

	IRDynamicChecks::~IRDynamicChecks() = default;

	bool IRDynamicChecks::runOnModule(llvm::Module &M) {
	Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));

	llvm::Function *function = M.getFunction(StringRef(m_func_name));

	if (!function) {
	if (log)
	log->Printf("Couldn't find %s() in the module", m_func_name.c_str());

	return false;
	}

	if (m_checker_functions.m_valid_pointer_check) {
	ValidPointerChecker vpc(M, m_checker_functions.m_valid_pointer_check);

	if (!vpc.Inspect(*function))
	return false;

	if (!vpc.Instrument())
	return false;
	}

	if (m_checker_functions.m_objc_object_check) {
	ObjcObjectChecker ooc(M, m_checker_functions.m_objc_object_check);

	if (!ooc.Inspect(*function))
	return false;

	if (!ooc.Instrument())
	return false;
	}

	if (log && log->GetVerbose()) {
	std::string s;
	raw_string_ostream oss(s);

	M.print(oss, nullptr);

	oss.flush();

	log->Printf("Module after dynamic checks: \n%s", s.c_str());
	}

	return true;
	}

	void IRDynamicChecks::assignPassManager(PMStack &PMS, PassManagerType T) {}

	PassManagerType IRDynamicChecks::getPotentialPassManagerType() const {
	return PMT_ModulePassManager;
	}

lldb/trunk/source/Plugins/ExpressionParser/Clang/CMakeLists.txt

Show All 13 Lines	add_lldb_library(lldbPluginExpressionParserClang PLUGIN
ClangExpressionVariable.cpp		ClangExpressionVariable.cpp
ClangFunctionCaller.cpp		ClangFunctionCaller.cpp
ClangHost.cpp		ClangHost.cpp
ClangModulesDeclVendor.cpp		ClangModulesDeclVendor.cpp
ClangPersistentVariables.cpp		ClangPersistentVariables.cpp
ClangUserExpression.cpp		ClangUserExpression.cpp
ClangUtilityFunction.cpp		ClangUtilityFunction.cpp
IRForTarget.cpp		IRForTarget.cpp
		IRDynamicChecks.cpp

DEPENDS		DEPENDS
${tablegen_deps}		${tablegen_deps}

LINK_LIBS		LINK_LIBS
clangAST		clangAST
clangCodeGen		clangCodeGen
clangDriver		clangDriver
Show All 23 Lines

lldb/trunk/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp

Show First 20 Lines • Show All 56 Lines • ▼ Show 20 Lines
#include "ClangASTSource.h"		#include "ClangASTSource.h"
#include "ClangDiagnostic.h"		#include "ClangDiagnostic.h"
#include "ClangExpressionDeclMap.h"		#include "ClangExpressionDeclMap.h"
#include "ClangExpressionHelper.h"		#include "ClangExpressionHelper.h"
#include "ClangExpressionParser.h"		#include "ClangExpressionParser.h"
#include "ClangHost.h"		#include "ClangHost.h"
#include "ClangModulesDeclVendor.h"		#include "ClangModulesDeclVendor.h"
#include "ClangPersistentVariables.h"		#include "ClangPersistentVariables.h"
		#include "IRDynamicChecks.h"
#include "IRForTarget.h"		#include "IRForTarget.h"
#include "ModuleDependencyCollector.h"		#include "ModuleDependencyCollector.h"

#include "lldb/Core/Debugger.h"		#include "lldb/Core/Debugger.h"
#include "lldb/Core/Disassembler.h"		#include "lldb/Core/Disassembler.h"
#include "lldb/Core/Module.h"		#include "lldb/Core/Module.h"
#include "lldb/Core/StreamFile.h"		#include "lldb/Core/StreamFile.h"
#include "lldb/Expression/IRDynamicChecks.h"
#include "lldb/Expression/IRExecutionUnit.h"		#include "lldb/Expression/IRExecutionUnit.h"
#include "lldb/Expression/IRInterpreter.h"		#include "lldb/Expression/IRInterpreter.h"
#include "lldb/Host/File.h"		#include "lldb/Host/File.h"
#include "lldb/Host/HostInfo.h"		#include "lldb/Host/HostInfo.h"
#include "lldb/Symbol/ClangASTContext.h"		#include "lldb/Symbol/ClangASTContext.h"
#include "lldb/Symbol/SymbolVendor.h"		#include "lldb/Symbol/SymbolVendor.h"
#include "lldb/Target/ExecutionContext.h"		#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Language.h"		#include "lldb/Target/Language.h"
▲ Show 20 Lines • Show All 1,195 Lines • ▼ Show 20 Lines	if (!process && execution_policy == eExecutionPolicyTopLevel) {
"target, but the target can't be run");		"target, but the target can't be run");
return err;		return err;
}		}

if (execution_policy == eExecutionPolicyAlways \|\|		if (execution_policy == eExecutionPolicyAlways \|\|
(execution_policy != eExecutionPolicyTopLevel && !can_interpret)) {		(execution_policy != eExecutionPolicyTopLevel && !can_interpret)) {
if (m_expr.NeedsValidation() && process) {		if (m_expr.NeedsValidation() && process) {
if (!process->GetDynamicCheckers()) {		if (!process->GetDynamicCheckers()) {
DynamicCheckerFunctions *dynamic_checkers =		ClangDynamicCheckerFunctions *dynamic_checkers =
new DynamicCheckerFunctions();		new ClangDynamicCheckerFunctions();

DiagnosticManager install_diagnostics;		DiagnosticManager install_diagnostics;

if (!dynamic_checkers->Install(install_diagnostics, exe_ctx)) {		if (!dynamic_checkers->Install(install_diagnostics, exe_ctx)) {
if (install_diagnostics.Diagnostics().size())		if (install_diagnostics.Diagnostics().size())
err.SetErrorString(install_diagnostics.GetString().c_str());		err.SetErrorString(install_diagnostics.GetString().c_str());
else		else
err.SetErrorString("couldn't install checkers, unknown error");		err.SetErrorString("couldn't install checkers, unknown error");

return err;		return err;
}		}

process->SetDynamicCheckers(dynamic_checkers);		process->SetDynamicCheckers(dynamic_checkers);

if (log)		if (log)
log->Printf("== [ClangExpressionParser::PrepareForExecution] "		log->Printf("== [ClangExpressionParser::PrepareForExecution] "
"Finished installing dynamic checkers ==");		"Finished installing dynamic checkers ==");
}		}

IRDynamicChecks ir_dynamic_checks(*process->GetDynamicCheckers(),		if (auto *checker_funcs = llvm::dyn_cast<ClangDynamicCheckerFunctions>(
		process->GetDynamicCheckers())) {
		IRDynamicChecks ir_dynamic_checks(*checker_funcs,
function_name.AsCString());		function_name.AsCString());

llvm::Module *module = execution_unit_sp->GetModule();		llvm::Module *module = execution_unit_sp->GetModule();
if (!module \|\| !ir_dynamic_checks.runOnModule(*module)) {		if (!module \|\| !ir_dynamic_checks.runOnModule(*module)) {
err.SetErrorToGenericError();		err.SetErrorToGenericError();
err.SetErrorString("Couldn't add dynamic checks to the expression");		err.SetErrorString("Couldn't add dynamic checks to the expression");
return err;		return err;
}		}

if (custom_passes.LatePasses) {		if (custom_passes.LatePasses) {
if (log)		if (log)
log->Printf("%s - Running Late IR Passes from LanguageRuntime on "		log->Printf("%s - Running Late IR Passes from LanguageRuntime on "
"expression module '%s'",		"expression module '%s'",
__FUNCTION__, m_expr.FunctionName());		__FUNCTION__, m_expr.FunctionName());

custom_passes.LatePasses->run(*module);		custom_passes.LatePasses->run(*module);
}		}
}		}
}		}
		}

if (execution_policy == eExecutionPolicyAlways \|\|		if (execution_policy == eExecutionPolicyAlways \|\|
execution_policy == eExecutionPolicyTopLevel \|\| !can_interpret) {		execution_policy == eExecutionPolicyTopLevel \|\| !can_interpret) {
execution_unit_sp->GetRunnableInfo(err, func_addr, func_end);		execution_unit_sp->GetRunnableInfo(err, func_addr, func_end);
}		}
} else {		} else {
execution_unit_sp->GetRunnableInfo(err, func_addr, func_end);		execution_unit_sp->GetRunnableInfo(err, func_addr, func_end);
}		}
▲ Show 20 Lines • Show All 47 Lines • Show Last 20 Lines

lldb/trunk/source/Plugins/ExpressionParser/Clang/IRDynamicChecks.h

				//===-- IRDynamicChecks.h ---------------------------------------- C++ --===//
				//
				// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
				// See https://llvm.org/LICENSE.txt for license information.
				// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
				//
				//===----------------------------------------------------------------------===//

				#ifndef liblldb_IRDynamicChecks_h_
				#define liblldb_IRDynamicChecks_h_

				#include "lldb/Expression/DynamicCheckerFunctions.h"
				#include "lldb/lldb-types.h"
				#include "llvm/Pass.h"

				namespace llvm {
				class BasicBlock;
				class Module;
				}

				namespace lldb_private {

				class ExecutionContext;
				class Stream;

				class ClangDynamicCheckerFunctions
				: public lldb_private::DynamicCheckerFunctions {
				public:
				/// Constructor
				ClangDynamicCheckerFunctions();

				/// Destructor
				virtual ~ClangDynamicCheckerFunctions();

				static bool classof(const DynamicCheckerFunctions *checker_funcs) {
				return checker_funcs->GetKind() == DCF_Clang;
				}

				/// Install the utility functions into a process. This binds the instance
				/// of DynamicCheckerFunctions to that process.
				///
				/// \param[in] diagnostic_manager
				/// A diagnostic manager to report errors to.
				///
				/// \param[in] exe_ctx
				/// The execution context to install the functions into.
				///
				/// \return
				/// True on success; false on failure, or if the functions have
				/// already been installed.
				bool Install(DiagnosticManager &diagnostic_manager,
				ExecutionContext &exe_ctx) override;

				bool DoCheckersExplainStop(lldb::addr_t addr, Stream &message) override;

				std::shared_ptr<UtilityFunction> m_valid_pointer_check;
				std::shared_ptr<UtilityFunction> m_objc_object_check;
				};

				/// \class IRDynamicChecks IRDynamicChecks.h
				/// "lldb/Expression/IRDynamicChecks.h" Adds dynamic checks to a user-entered
				/// expression to reduce its likelihood of crashing
				///
				/// When an IR function is executed in the target process, it may cause
				/// crashes or hangs by dereferencing NULL pointers, trying to call
				/// Objective-C methods on objects that do not respond to them, and so forth.
				///
				/// IRDynamicChecks adds calls to the functions in DynamicCheckerFunctions to
				/// appropriate locations in an expression's IR.
				class IRDynamicChecks : public llvm::ModulePass {
				public:
				/// Constructor
				///
				/// \param[in] checker_functions
				/// The checker functions for the target process.
				///
				/// \param[in] func_name
				/// The name of the function to prepare for execution in the target.
				///
				/// \param[in] decl_map
				/// The mapping used to look up entities in the target process. In
				/// this case, used to find objc_msgSend
				IRDynamicChecks(ClangDynamicCheckerFunctions &checker_functions,
				const char *func_name = "$__lldb_expr");

				/// Destructor
				~IRDynamicChecks() override;

				/// Run this IR transformer on a single module
				///
				/// \param[in] M
				/// The module to run on. This module is searched for the function
				/// $__lldb_expr, and that function is passed to the passes one by
				/// one.
				///
				/// \return
				/// True on success; false otherwise
				bool runOnModule(llvm::Module &M) override;

				/// Interface stub
				void assignPassManager(
				llvm::PMStack &PMS,
				llvm::PassManagerType T = llvm::PMT_ModulePassManager) override;

				/// Returns PMT_ModulePassManager
				llvm::PassManagerType getPotentialPassManagerType() const override;

				private:
				/// A basic block-level pass to find all pointer dereferences and
				/// validate them before use.

				/// The top-level pass implementation
				///
				/// \param[in] M
				/// The module currently being processed.
				///
				/// \param[in] BB
				/// The basic block currently being processed.
				///
				/// \return
				/// True on success; false otherwise
				bool FindDataLoads(llvm::Module &M, llvm::BasicBlock &BB);

				std::string m_func_name; ///< The name of the function to add checks to
				ClangDynamicCheckerFunctions
				&m_checker_functions; ///< The checker functions for the process
				};

				} // namespace lldb_private

				#endif // liblldb_IRDynamicChecks_h_

lldb/trunk/source/Plugins/ExpressionParser/Clang/IRDynamicChecks.cpp

				//===-- IRDynamicChecks.cpp -------------------------------------- C++ --===//
				//
				// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
				// See https://llvm.org/LICENSE.txt for license information.
				// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
				//
				//===----------------------------------------------------------------------===//

				#include "llvm/IR/Constants.h"
				#include "llvm/IR/DataLayout.h"
				#include "llvm/IR/Function.h"
				#include "llvm/IR/Instructions.h"
				#include "llvm/IR/Module.h"
				#include "llvm/IR/Value.h"
				#include "llvm/Support/raw_ostream.h"

				#include "IRDynamicChecks.h"

				#include "lldb/Expression/UtilityFunction.h"
				#include "lldb/Target/ExecutionContext.h"
				#include "lldb/Target/ObjCLanguageRuntime.h"
				#include "lldb/Target/Process.h"
				#include "lldb/Target/StackFrame.h"
				#include "lldb/Target/Target.h"
				#include "lldb/Utility/ConstString.h"
				#include "lldb/Utility/Log.h"

				using namespace llvm;
				using namespace lldb_private;

				static char ID;

				#define VALID_POINTER_CHECK_NAME "_$__lldb_valid_pointer_check"
				#define VALID_OBJC_OBJECT_CHECK_NAME "$__lldb_objc_object_check"

				static const char g_valid_pointer_check_text[] =
				"extern \"C\" void\n"
				"_$__lldb_valid_pointer_check (unsigned char *$__lldb_arg_ptr)\n"
				"{\n"
				" unsigned char $__lldb_local_val = *$__lldb_arg_ptr;\n"
				"}";

				ClangDynamicCheckerFunctions::ClangDynamicCheckerFunctions()
				: DynamicCheckerFunctions(DCF_Clang) {}

				ClangDynamicCheckerFunctions::~ClangDynamicCheckerFunctions() = default;

				bool ClangDynamicCheckerFunctions::Install(
				DiagnosticManager &diagnostic_manager, ExecutionContext &exe_ctx) {
				Status error;
				m_valid_pointer_check.reset(
				exe_ctx.GetTargetRef().GetUtilityFunctionForLanguage(
				g_valid_pointer_check_text, lldb::eLanguageTypeC,
				VALID_POINTER_CHECK_NAME, error));
				if (error.Fail())
				return false;

				if (!m_valid_pointer_check->Install(diagnostic_manager, exe_ctx))
				return false;

				Process *process = exe_ctx.GetProcessPtr();

				if (process) {
				ObjCLanguageRuntime *objc_language_runtime =
				ObjCLanguageRuntime::Get(*process);

				if (objc_language_runtime) {
				m_objc_object_check.reset(objc_language_runtime->CreateObjectChecker(
				VALID_OBJC_OBJECT_CHECK_NAME));

				if (!m_objc_object_check->Install(diagnostic_manager, exe_ctx))
				return false;
				}
				}

				return true;
				}

				bool ClangDynamicCheckerFunctions::DoCheckersExplainStop(lldb::addr_t addr,
				Stream &message) {
				// FIXME: We have to get the checkers to know why they scotched the call in
				// more detail,
				// so we can print a better message here.
				if (m_valid_pointer_check && m_valid_pointer_check->ContainsAddress(addr)) {
				message.Printf("Attempted to dereference an invalid pointer.");
				return true;
				} else if (m_objc_object_check &&
				m_objc_object_check->ContainsAddress(addr)) {
				message.Printf("Attempted to dereference an invalid ObjC Object or send it "
				"an unrecognized selector");
				return true;
				}
				return false;
				}

				static std::string PrintValue(llvm::Value *V, bool truncate = false) {
				std::string s;
				raw_string_ostream rso(s);
				V->print(rso);
				rso.flush();
				if (truncate)
				s.resize(s.length() - 1);
				return s;
				}

				/// \class Instrumenter IRDynamicChecks.cpp
				/// Finds and instruments individual LLVM IR instructions
				///
				/// When instrumenting LLVM IR, it is frequently desirable to first search for
				/// instructions, and then later modify them. This way iterators remain
				/// intact, and multiple passes can look at the same code base without
				/// treading on each other's toes.
				///
				/// The Instrumenter class implements this functionality. A client first
				/// calls Inspect on a function, which populates a list of instructions to be
				/// instrumented. Then, later, when all passes' Inspect functions have been
				/// called, the client calls Instrument, which adds the desired
				/// instrumentation.
				///
				/// A subclass of Instrumenter must override InstrumentInstruction, which
				/// is responsible for adding whatever instrumentation is necessary.
				///
				/// A subclass of Instrumenter may override:
				///
				/// - InspectInstruction [default: does nothing]
				///
				/// - InspectBasicBlock [default: iterates through the instructions in a
				/// basic block calling InspectInstruction]
				///
				/// - InspectFunction [default: iterates through the basic blocks in a
				/// function calling InspectBasicBlock]
				class Instrumenter {
				public:
				/// Constructor
				///
				/// \param[in] module
				/// The module being instrumented.
				Instrumenter(llvm::Module &module,
				std::shared_ptr<UtilityFunction> checker_function)
				: m_module(module), m_checker_function(checker_function),
				m_i8ptr_ty(nullptr), m_intptr_ty(nullptr) {}

				virtual ~Instrumenter() = default;

				/// Inspect a function to find instructions to instrument
				///
				/// \param[in] function
				/// The function to inspect.
				///
				/// \return
				/// True on success; false on error.
				bool Inspect(llvm::Function &function) { return InspectFunction(function); }

				/// Instrument all the instructions found by Inspect()
				///
				/// \return
				/// True on success; false on error.
				bool Instrument() {
				for (InstIterator ii = m_to_instrument.begin(),
				last_ii = m_to_instrument.end();
				ii != last_ii; ++ii) {
				if (!InstrumentInstruction(*ii))
				return false;
				}

				return true;
				}

				protected:
				/// Add instrumentation to a single instruction
				///
				/// \param[in] inst
				/// The instruction to be instrumented.
				///
				/// \return
				/// True on success; false otherwise.
				virtual bool InstrumentInstruction(llvm::Instruction *inst) = 0;

				/// Register a single instruction to be instrumented
				///
				/// \param[in] inst
				/// The instruction to be instrumented.
				void RegisterInstruction(llvm::Instruction &i) {
				m_to_instrument.push_back(&i);
				}

				/// Determine whether a single instruction is interesting to instrument,
				/// and, if so, call RegisterInstruction
				///
				/// \param[in] i
				/// The instruction to be inspected.
				///
				/// \return
				/// False if there was an error scanning; true otherwise.
				virtual bool InspectInstruction(llvm::Instruction &i) { return true; }

				/// Scan a basic block to see if any instructions are interesting
				///
				/// \param[in] bb
				/// The basic block to be inspected.
				///
				/// \return
				/// False if there was an error scanning; true otherwise.
				virtual bool InspectBasicBlock(llvm::BasicBlock &bb) {
				for (llvm::BasicBlock::iterator ii = bb.begin(), last_ii = bb.end();
				ii != last_ii; ++ii) {
				if (!InspectInstruction(*ii))
				return false;
				}

				return true;
				}

				/// Scan a function to see if any instructions are interesting
				///
				/// \param[in] f
				/// The function to be inspected.
				///
				/// \return
				/// False if there was an error scanning; true otherwise.
				virtual bool InspectFunction(llvm::Function &f) {
				for (llvm::Function::iterator bbi = f.begin(), last_bbi = f.end();
				bbi != last_bbi; ++bbi) {
				if (!InspectBasicBlock(*bbi))
				return false;
				}

				return true;
				}

				/// Build a function pointer for a function with signature void
				/// ()(uint8_t) with a given address
				///
				/// \param[in] start_address
				/// The address of the function.
				///
				/// \return
				/// The function pointer, for use in a CallInst.
				llvm::FunctionCallee BuildPointerValidatorFunc(lldb::addr_t start_address) {
				llvm::Type *param_array[1];

				param_array[0] = const_cast<llvm::PointerType *>(GetI8PtrTy());

				ArrayRef<llvm::Type *> params(param_array, 1);

				FunctionType *fun_ty = FunctionType::get(
				llvm::Type::getVoidTy(m_module.getContext()), params, true);
				PointerType *fun_ptr_ty = PointerType::getUnqual(fun_ty);
				Constant *fun_addr_int =
				ConstantInt::get(GetIntptrTy(), start_address, false);
				return {fun_ty, ConstantExpr::getIntToPtr(fun_addr_int, fun_ptr_ty)};
				}

				/// Build a function pointer for a function with signature void
				/// ()(uint8_t, uint8_t*) with a given address
				///
				/// \param[in] start_address
				/// The address of the function.
				///
				/// \return
				/// The function pointer, for use in a CallInst.
				llvm::FunctionCallee BuildObjectCheckerFunc(lldb::addr_t start_address) {
				llvm::Type *param_array[2];

				param_array[0] = const_cast<llvm::PointerType *>(GetI8PtrTy());
				param_array[1] = const_cast<llvm::PointerType *>(GetI8PtrTy());

				ArrayRef<llvm::Type *> params(param_array, 2);

				FunctionType *fun_ty = FunctionType::get(
				llvm::Type::getVoidTy(m_module.getContext()), params, true);
				PointerType *fun_ptr_ty = PointerType::getUnqual(fun_ty);
				Constant *fun_addr_int =
				ConstantInt::get(GetIntptrTy(), start_address, false);
				return {fun_ty, ConstantExpr::getIntToPtr(fun_addr_int, fun_ptr_ty)};
				}

				PointerType *GetI8PtrTy() {
				if (!m_i8ptr_ty)
				m_i8ptr_ty = llvm::Type::getInt8PtrTy(m_module.getContext());

				return m_i8ptr_ty;
				}

				IntegerType *GetIntptrTy() {
				if (!m_intptr_ty) {
				llvm::DataLayout data_layout(&m_module);

				m_intptr_ty = llvm::Type::getIntNTy(m_module.getContext(),
				data_layout.getPointerSizeInBits());
				}

				return m_intptr_ty;
				}

				typedef std::vector<llvm::Instruction *> InstVector;
				typedef InstVector::iterator InstIterator;

				InstVector m_to_instrument; ///< List of instructions the inspector found
				llvm::Module &m_module; ///< The module which is being instrumented
				std::shared_ptr<UtilityFunction>
				m_checker_function; ///< The dynamic checker function for the process

				private:
				PointerType *m_i8ptr_ty;
				IntegerType *m_intptr_ty;
				};

				class ValidPointerChecker : public Instrumenter {
				public:
				ValidPointerChecker(llvm::Module &module,
				std::shared_ptr<UtilityFunction> checker_function)
				: Instrumenter(module, checker_function),
				m_valid_pointer_check_func(nullptr) {}

				~ValidPointerChecker() override = default;

				protected:
				bool InstrumentInstruction(llvm::Instruction *inst) override {
				Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));

				if (log)
				log->Printf("Instrumenting load/store instruction: %s\n",
				PrintValue(inst).c_str());

				if (!m_valid_pointer_check_func)
				m_valid_pointer_check_func =
				BuildPointerValidatorFunc(m_checker_function->StartAddress());

				llvm::Value *dereferenced_ptr = nullptr;

				if (llvm::LoadInst *li = dyn_cast<llvm::LoadInst>(inst))
				dereferenced_ptr = li->getPointerOperand();
				else if (llvm::StoreInst *si = dyn_cast<llvm::StoreInst>(inst))
				dereferenced_ptr = si->getPointerOperand();
				else
				return false;

				// Insert an instruction to cast the loaded value to int8_t*

				BitCastInst *bit_cast =
				new BitCastInst(dereferenced_ptr, GetI8PtrTy(), "", inst);

				// Insert an instruction to call the helper with the result

				llvm::Value *arg_array[1];

				arg_array[0] = bit_cast;

				llvm::ArrayRef<llvm::Value *> args(arg_array, 1);

				CallInst::Create(m_valid_pointer_check_func, args, "", inst);

				return true;
				}

				bool InspectInstruction(llvm::Instruction &i) override {
				if (dyn_cast<llvm::LoadInst>(&i) \|\| dyn_cast<llvm::StoreInst>(&i))
				RegisterInstruction(i);

				return true;
				}

				private:
				llvm::FunctionCallee m_valid_pointer_check_func;
				};

				class ObjcObjectChecker : public Instrumenter {
				public:
				ObjcObjectChecker(llvm::Module &module,
				std::shared_ptr<UtilityFunction> checker_function)
				: Instrumenter(module, checker_function),
				m_objc_object_check_func(nullptr) {}

				~ObjcObjectChecker() override = default;

				enum msgSend_type {
				eMsgSend = 0,
				eMsgSendSuper,
				eMsgSendSuper_stret,
				eMsgSend_fpret,
				eMsgSend_stret
				};

				std::map<llvm::Instruction *, msgSend_type> msgSend_types;

				protected:
				bool InstrumentInstruction(llvm::Instruction *inst) override {
				CallInst *call_inst = dyn_cast<CallInst>(inst);

				if (!call_inst)
				return false; // call_inst really shouldn't be nullptr, because otherwise
				// InspectInstruction wouldn't have registered it

				if (!m_objc_object_check_func)
				m_objc_object_check_func =
				BuildObjectCheckerFunc(m_checker_function->StartAddress());

				// id objc_msgSend(id theReceiver, SEL theSelector, ...)

				llvm::Value *target_object;
				llvm::Value *selector;

				switch (msgSend_types[inst]) {
				case eMsgSend:
				case eMsgSend_fpret:
				// On arm64, clang uses objc_msgSend for scalar and struct return
				// calls. The call instruction will record which was used.
				if (call_inst->hasStructRetAttr()) {
				target_object = call_inst->getArgOperand(1);
				selector = call_inst->getArgOperand(2);
				} else {
				target_object = call_inst->getArgOperand(0);
				selector = call_inst->getArgOperand(1);
				}
				break;
				case eMsgSend_stret:
				target_object = call_inst->getArgOperand(1);
				selector = call_inst->getArgOperand(2);
				break;
				case eMsgSendSuper:
				case eMsgSendSuper_stret:
				return true;
				}

				// These objects should always be valid according to Sean Calannan
				assert(target_object);
				assert(selector);

				// Insert an instruction to cast the receiver id to int8_t*

				BitCastInst *bit_cast =
				new BitCastInst(target_object, GetI8PtrTy(), "", inst);

				// Insert an instruction to call the helper with the result

				llvm::Value *arg_array[2];

				arg_array[0] = bit_cast;
				arg_array[1] = selector;

				ArrayRef<llvm::Value *> args(arg_array, 2);

				CallInst::Create(m_objc_object_check_func, args, "", inst);

				return true;
				}

				static llvm::Function GetFunction(llvm::Value value) {
				if (llvm::Function *function = llvm::dyn_cast<llvm::Function>(value)) {
				return function;
				}

				if (llvm::ConstantExpr *const_expr =
				llvm::dyn_cast<llvm::ConstantExpr>(value)) {
				switch (const_expr->getOpcode()) {
				default:
				return nullptr;
				case llvm::Instruction::BitCast:
				return GetFunction(const_expr->getOperand(0));
				}
				}

				return nullptr;
				}

				static llvm::Function GetCalledFunction(llvm::CallInst inst) {
				return GetFunction(inst->getCalledValue());
				}

				bool InspectInstruction(llvm::Instruction &i) override {
				Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));

				CallInst *call_inst = dyn_cast<CallInst>(&i);

				if (call_inst) {
				const llvm::Function *called_function = GetCalledFunction(call_inst);

				if (!called_function)
				return true;

				std::string name_str = called_function->getName().str();
				const char *name_cstr = name_str.c_str();

				if (log)
				log->Printf("Found call to %s: %s\n", name_cstr,
				PrintValue(call_inst).c_str());

				if (name_str.find("objc_msgSend") == std::string::npos)
				return true;

				if (!strcmp(name_cstr, "objc_msgSend")) {
				RegisterInstruction(i);
				msgSend_types[&i] = eMsgSend;
				return true;
				}

				if (!strcmp(name_cstr, "objc_msgSend_stret")) {
				RegisterInstruction(i);
				msgSend_types[&i] = eMsgSend_stret;
				return true;
				}

				if (!strcmp(name_cstr, "objc_msgSend_fpret")) {
				RegisterInstruction(i);
				msgSend_types[&i] = eMsgSend_fpret;
				return true;
				}

				if (!strcmp(name_cstr, "objc_msgSendSuper")) {
				RegisterInstruction(i);
				msgSend_types[&i] = eMsgSendSuper;
				return true;
				}

				if (!strcmp(name_cstr, "objc_msgSendSuper_stret")) {
				RegisterInstruction(i);
				msgSend_types[&i] = eMsgSendSuper_stret;
				return true;
				}

				if (log)
				log->Printf(
				"Function name '%s' contains 'objc_msgSend' but is not handled",
				name_str.c_str());

				return true;
				}

				return true;
				}

				private:
				llvm::FunctionCallee m_objc_object_check_func;
				};

				IRDynamicChecks::IRDynamicChecks(
				ClangDynamicCheckerFunctions &checker_functions, const char *func_name)
				: ModulePass(ID), m_func_name(func_name),
				m_checker_functions(checker_functions) {}

				IRDynamicChecks::~IRDynamicChecks() = default;

				bool IRDynamicChecks::runOnModule(llvm::Module &M) {
				Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));

				llvm::Function *function = M.getFunction(StringRef(m_func_name));

				if (!function) {
				if (log)
				log->Printf("Couldn't find %s() in the module", m_func_name.c_str());

				return false;
				}

				if (m_checker_functions.m_valid_pointer_check) {
				ValidPointerChecker vpc(M, m_checker_functions.m_valid_pointer_check);

				if (!vpc.Inspect(*function))
				return false;

				if (!vpc.Instrument())
				return false;
				}

				if (m_checker_functions.m_objc_object_check) {
				ObjcObjectChecker ooc(M, m_checker_functions.m_objc_object_check);

				if (!ooc.Inspect(*function))
				return false;

				if (!ooc.Instrument())
				return false;
				}

				if (log && log->GetVerbose()) {
				std::string s;
				raw_string_ostream oss(s);

				M.print(oss, nullptr);

				oss.flush();

				log->Printf("Module after dynamic checks: \n%s", s.c_str());
				}

				return true;
				}

				void IRDynamicChecks::assignPassManager(PMStack &PMS, PassManagerType T) {}

				PassManagerType IRDynamicChecks::getPotentialPassManagerType() const {
				return PMT_ModulePassManager;
				}

lldb/trunk/source/Target/Process.cpp

	Show All 16 Lines
	#include "lldb/Breakpoint/BreakpointLocation.h"			#include "lldb/Breakpoint/BreakpointLocation.h"
	#include "lldb/Breakpoint/StoppointCallbackContext.h"			#include "lldb/Breakpoint/StoppointCallbackContext.h"
	#include "lldb/Core/Debugger.h"			#include "lldb/Core/Debugger.h"
	#include "lldb/Core/Module.h"			#include "lldb/Core/Module.h"
	#include "lldb/Core/ModuleSpec.h"			#include "lldb/Core/ModuleSpec.h"
	#include "lldb/Core/PluginManager.h"			#include "lldb/Core/PluginManager.h"
	#include "lldb/Core/StreamFile.h"			#include "lldb/Core/StreamFile.h"
	#include "lldb/Expression/DiagnosticManager.h"			#include "lldb/Expression/DiagnosticManager.h"
	#include "lldb/Expression/IRDynamicChecks.h"			#include "lldb/Expression/DynamicCheckerFunctions.h"
	#include "lldb/Expression/UserExpression.h"			#include "lldb/Expression/UserExpression.h"
	#include "lldb/Expression/UtilityFunction.h"			#include "lldb/Expression/UtilityFunction.h"
	#include "lldb/Host/ConnectionFileDescriptor.h"			#include "lldb/Host/ConnectionFileDescriptor.h"
	#include "lldb/Host/FileSystem.h"			#include "lldb/Host/FileSystem.h"
	#include "lldb/Host/Host.h"			#include "lldb/Host/Host.h"
	#include "lldb/Host/HostInfo.h"			#include "lldb/Host/HostInfo.h"
	#include "lldb/Host/OptionParser.h"			#include "lldb/Host/OptionParser.h"
	#include "lldb/Host/Pipe.h"			#include "lldb/Host/Pipe.h"
	▲ Show 20 Lines • Show All 6,015 Lines • Show Last 20 Lines

lldb/trunk/source/Target/ThreadPlanCallUserExpression.cpp

	//===-- ThreadPlanCallUserExpression.cpp -------------------------- C++--===//			//===-- ThreadPlanCallUserExpression.cpp -------------------------- C++--===//
	//			//
	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.			// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
	// See https://llvm.org/LICENSE.txt for license information.			// See https://llvm.org/LICENSE.txt for license information.
	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception			// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
	//			//
	//===----------------------------------------------------------------------===//			//===----------------------------------------------------------------------===//

	#include "lldb/Target/ThreadPlanCallUserExpression.h"			#include "lldb/Target/ThreadPlanCallUserExpression.h"


	#include "lldb/Breakpoint/Breakpoint.h"			#include "lldb/Breakpoint/Breakpoint.h"
	#include "lldb/Breakpoint/BreakpointLocation.h"			#include "lldb/Breakpoint/BreakpointLocation.h"
	#include "lldb/Core/Address.h"			#include "lldb/Core/Address.h"
	#include "lldb/Expression/DiagnosticManager.h"			#include "lldb/Expression/DiagnosticManager.h"
	#include "lldb/Expression/IRDynamicChecks.h"			#include "lldb/Expression/DynamicCheckerFunctions.h"
	#include "lldb/Expression/UserExpression.h"			#include "lldb/Expression/UserExpression.h"
	#include "lldb/Host/HostInfo.h"			#include "lldb/Host/HostInfo.h"
	#include "lldb/Target/LanguageRuntime.h"			#include "lldb/Target/LanguageRuntime.h"
	#include "lldb/Target/Process.h"			#include "lldb/Target/Process.h"
	#include "lldb/Target/RegisterContext.h"			#include "lldb/Target/RegisterContext.h"
	#include "lldb/Target/StopInfo.h"			#include "lldb/Target/StopInfo.h"
	#include "lldb/Target/Target.h"			#include "lldb/Target/Target.h"
	#include "lldb/Target/Thread.h"			#include "lldb/Target/Thread.h"
	▲ Show 20 Lines • Show All 95 Lines • Show Last 20 Lines