forked from OSchip/llvm-project
674 lines
21 KiB
C++
674 lines
21 KiB
C++
//===-- IRDynamicChecks.cpp -------------------------------------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "lldb/Expression/IRDynamicChecks.h"
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#include "lldb/Core/ConstString.h"
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#include "lldb/Core/Log.h"
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#include "lldb/Expression/ClangUtilityFunction.h"
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#include "lldb/Target/ExecutionContext.h"
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#include "lldb/Target/ObjCLanguageRuntime.h"
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#include "lldb/Target/Process.h"
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#include "lldb/Target/StackFrame.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/IR/Constants.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/Instructions.h"
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#include "llvm/IR/Module.h"
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#include "llvm/IR/Value.h"
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using namespace llvm;
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using namespace lldb_private;
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static char ID;
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#define VALID_POINTER_CHECK_NAME "$__lldb_valid_pointer_check"
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#define VALID_OBJC_OBJECT_CHECK_NAME "$__lldb_objc_object_check"
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static const char g_valid_pointer_check_text[] =
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"extern \"C\" void\n"
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"$__lldb_valid_pointer_check (unsigned char *$__lldb_arg_ptr)\n"
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"{\n"
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" unsigned char $__lldb_local_val = *$__lldb_arg_ptr;\n"
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"}";
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DynamicCheckerFunctions::DynamicCheckerFunctions ()
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{
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}
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DynamicCheckerFunctions::~DynamicCheckerFunctions ()
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{
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}
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bool
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DynamicCheckerFunctions::Install(Stream &error_stream,
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ExecutionContext &exe_ctx)
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{
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m_valid_pointer_check.reset(new ClangUtilityFunction(g_valid_pointer_check_text,
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VALID_POINTER_CHECK_NAME));
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if (!m_valid_pointer_check->Install(error_stream, exe_ctx))
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return false;
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Process *process = exe_ctx.GetProcessPtr();
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if (process)
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{
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ObjCLanguageRuntime *objc_language_runtime = process->GetObjCLanguageRuntime();
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if (objc_language_runtime)
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{
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m_objc_object_check.reset(objc_language_runtime->CreateObjectChecker(VALID_OBJC_OBJECT_CHECK_NAME));
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if (!m_objc_object_check->Install(error_stream, exe_ctx))
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return false;
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}
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}
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return true;
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}
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bool
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DynamicCheckerFunctions::DoCheckersExplainStop (lldb::addr_t addr, Stream &message)
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{
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// FIXME: We have to get the checkers to know why they scotched the call in more detail,
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// so we can print a better message here.
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if (m_valid_pointer_check.get() != NULL && m_valid_pointer_check->ContainsAddress(addr))
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{
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message.Printf ("Attempted to dereference an invalid pointer.");
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return true;
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}
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else if (m_objc_object_check.get() != NULL && m_objc_object_check->ContainsAddress(addr))
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{
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message.Printf ("Attempted to dereference an invalid ObjC Object or send it an unrecognized selector");
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return true;
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}
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return false;
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}
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static std::string
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PrintValue(llvm::Value *V, bool truncate = false)
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{
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std::string s;
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raw_string_ostream rso(s);
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V->print(rso);
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rso.flush();
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if (truncate)
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s.resize(s.length() - 1);
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return s;
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}
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//----------------------------------------------------------------------
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/// @class Instrumenter IRDynamicChecks.cpp
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/// @brief Finds and instruments individual LLVM IR instructions
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///
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/// When instrumenting LLVM IR, it is frequently desirable to first search
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/// for instructions, and then later modify them. This way iterators
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/// remain intact, and multiple passes can look at the same code base without
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/// treading on each other's toes.
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///
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/// The Instrumenter class implements this functionality. A client first
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/// calls Inspect on a function, which populates a list of instructions to
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/// be instrumented. Then, later, when all passes' Inspect functions have
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/// been called, the client calls Instrument, which adds the desired
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/// instrumentation.
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///
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/// A subclass of Instrumenter must override InstrumentInstruction, which
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/// is responsible for adding whatever instrumentation is necessary.
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///
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/// A subclass of Instrumenter may override:
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///
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/// - InspectInstruction [default: does nothing]
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///
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/// - InspectBasicBlock [default: iterates through the instructions in a
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/// basic block calling InspectInstruction]
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///
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/// - InspectFunction [default: iterates through the basic blocks in a
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/// function calling InspectBasicBlock]
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//----------------------------------------------------------------------
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class Instrumenter {
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public:
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//------------------------------------------------------------------
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/// Constructor
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///
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/// @param[in] module
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/// The module being instrumented.
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//------------------------------------------------------------------
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Instrumenter (llvm::Module &module,
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DynamicCheckerFunctions &checker_functions) :
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m_module(module),
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m_checker_functions(checker_functions),
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m_i8ptr_ty(NULL),
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m_intptr_ty(NULL)
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{
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}
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virtual~Instrumenter ()
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{
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}
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//------------------------------------------------------------------
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/// Inspect a function to find instructions to instrument
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///
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/// @param[in] function
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/// The function to inspect.
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///
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/// @return
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/// True on success; false on error.
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//------------------------------------------------------------------
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bool Inspect (llvm::Function &function)
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{
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return InspectFunction(function);
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}
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//------------------------------------------------------------------
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/// Instrument all the instructions found by Inspect()
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///
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/// @return
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/// True on success; false on error.
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//------------------------------------------------------------------
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bool Instrument ()
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{
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for (InstIterator ii = m_to_instrument.begin(), last_ii = m_to_instrument.end();
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ii != last_ii;
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++ii)
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{
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if (!InstrumentInstruction(*ii))
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return false;
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}
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return true;
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}
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protected:
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//------------------------------------------------------------------
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/// Add instrumentation to a single instruction
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///
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/// @param[in] inst
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/// The instruction to be instrumented.
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///
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/// @return
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/// True on success; false otherwise.
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//------------------------------------------------------------------
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virtual bool InstrumentInstruction(llvm::Instruction *inst) = 0;
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//------------------------------------------------------------------
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/// Register a single instruction to be instrumented
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///
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/// @param[in] inst
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/// The instruction to be instrumented.
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//------------------------------------------------------------------
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void RegisterInstruction(llvm::Instruction &i)
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{
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m_to_instrument.push_back(&i);
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}
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//------------------------------------------------------------------
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/// Determine whether a single instruction is interesting to
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/// instrument, and, if so, call RegisterInstruction
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///
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/// @param[in] i
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/// The instruction to be inspected.
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///
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/// @return
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/// False if there was an error scanning; true otherwise.
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//------------------------------------------------------------------
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virtual bool InspectInstruction(llvm::Instruction &i)
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{
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return true;
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}
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//------------------------------------------------------------------
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/// Scan a basic block to see if any instructions are interesting
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///
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/// @param[in] bb
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/// The basic block to be inspected.
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///
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/// @return
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/// False if there was an error scanning; true otherwise.
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//------------------------------------------------------------------
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virtual bool InspectBasicBlock(llvm::BasicBlock &bb)
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{
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for (llvm::BasicBlock::iterator ii = bb.begin(), last_ii = bb.end();
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ii != last_ii;
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++ii)
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{
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if (!InspectInstruction(*ii))
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return false;
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}
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return true;
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}
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//------------------------------------------------------------------
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/// Scan a function to see if any instructions are interesting
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///
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/// @param[in] f
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/// The function to be inspected.
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///
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/// @return
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/// False if there was an error scanning; true otherwise.
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//------------------------------------------------------------------
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virtual bool InspectFunction(llvm::Function &f)
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{
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for (llvm::Function::iterator bbi = f.begin(), last_bbi = f.end();
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bbi != last_bbi;
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++bbi)
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{
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if (!InspectBasicBlock(*bbi))
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return false;
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}
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return true;
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}
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//------------------------------------------------------------------
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/// Build a function pointer for a function with signature
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/// void (*)(uint8_t*) with a given address
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///
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/// @param[in] start_address
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/// The address of the function.
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///
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/// @return
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/// The function pointer, for use in a CallInst.
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//------------------------------------------------------------------
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llvm::Value *BuildPointerValidatorFunc(lldb::addr_t start_address)
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{
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llvm::Type *param_array[1];
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param_array[0] = const_cast<llvm::PointerType*>(GetI8PtrTy());
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ArrayRef<llvm::Type*> params(param_array, 1);
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FunctionType *fun_ty = FunctionType::get(llvm::Type::getVoidTy(m_module.getContext()), params, true);
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PointerType *fun_ptr_ty = PointerType::getUnqual(fun_ty);
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Constant *fun_addr_int = ConstantInt::get(GetIntptrTy(), start_address, false);
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return ConstantExpr::getIntToPtr(fun_addr_int, fun_ptr_ty);
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}
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//------------------------------------------------------------------
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/// Build a function pointer for a function with signature
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/// void (*)(uint8_t*, uint8_t*) with a given address
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///
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/// @param[in] start_address
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/// The address of the function.
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///
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/// @return
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/// The function pointer, for use in a CallInst.
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//------------------------------------------------------------------
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llvm::Value *BuildObjectCheckerFunc(lldb::addr_t start_address)
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{
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llvm::Type *param_array[2];
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param_array[0] = const_cast<llvm::PointerType*>(GetI8PtrTy());
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param_array[1] = const_cast<llvm::PointerType*>(GetI8PtrTy());
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ArrayRef<llvm::Type*> params(param_array, 2);
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FunctionType *fun_ty = FunctionType::get(llvm::Type::getVoidTy(m_module.getContext()), params, true);
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PointerType *fun_ptr_ty = PointerType::getUnqual(fun_ty);
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Constant *fun_addr_int = ConstantInt::get(GetIntptrTy(), start_address, false);
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return ConstantExpr::getIntToPtr(fun_addr_int, fun_ptr_ty);
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}
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PointerType *GetI8PtrTy()
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{
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if (!m_i8ptr_ty)
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m_i8ptr_ty = llvm::Type::getInt8PtrTy(m_module.getContext());
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return m_i8ptr_ty;
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}
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IntegerType *GetIntptrTy()
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{
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if (!m_intptr_ty)
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{
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llvm::DataLayout data_layout(&m_module);
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m_intptr_ty = llvm::Type::getIntNTy(m_module.getContext(), data_layout.getPointerSizeInBits());
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}
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return m_intptr_ty;
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}
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typedef std::vector <llvm::Instruction *> InstVector;
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typedef InstVector::iterator InstIterator;
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InstVector m_to_instrument; ///< List of instructions the inspector found
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llvm::Module &m_module; ///< The module which is being instrumented
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DynamicCheckerFunctions &m_checker_functions; ///< The dynamic checker functions for the process
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private:
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PointerType *m_i8ptr_ty;
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IntegerType *m_intptr_ty;
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};
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class ValidPointerChecker : public Instrumenter
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{
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public:
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ValidPointerChecker (llvm::Module &module,
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DynamicCheckerFunctions &checker_functions) :
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Instrumenter(module, checker_functions),
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m_valid_pointer_check_func(NULL)
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{
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}
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virtual ~ValidPointerChecker ()
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{
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}
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private:
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bool InstrumentInstruction(llvm::Instruction *inst)
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{
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Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
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if (log)
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log->Printf("Instrumenting load/store instruction: %s\n",
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PrintValue(inst).c_str());
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if (!m_valid_pointer_check_func)
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m_valid_pointer_check_func = BuildPointerValidatorFunc(m_checker_functions.m_valid_pointer_check->StartAddress());
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llvm::Value *dereferenced_ptr = NULL;
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if (llvm::LoadInst *li = dyn_cast<llvm::LoadInst> (inst))
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dereferenced_ptr = li->getPointerOperand();
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else if (llvm::StoreInst *si = dyn_cast<llvm::StoreInst> (inst))
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dereferenced_ptr = si->getPointerOperand();
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else
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return false;
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// Insert an instruction to cast the loaded value to int8_t*
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BitCastInst *bit_cast = new BitCastInst(dereferenced_ptr,
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GetI8PtrTy(),
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"",
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inst);
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// Insert an instruction to call the helper with the result
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llvm::Value *arg_array[1];
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arg_array[0] = bit_cast;
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llvm::ArrayRef<llvm::Value *> args(arg_array, 1);
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CallInst::Create(m_valid_pointer_check_func,
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args,
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"",
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inst);
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return true;
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}
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bool InspectInstruction(llvm::Instruction &i)
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{
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if (dyn_cast<llvm::LoadInst> (&i) ||
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dyn_cast<llvm::StoreInst> (&i))
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RegisterInstruction(i);
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return true;
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}
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llvm::Value *m_valid_pointer_check_func;
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};
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class ObjcObjectChecker : public Instrumenter
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{
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public:
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ObjcObjectChecker(llvm::Module &module,
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DynamicCheckerFunctions &checker_functions) :
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Instrumenter(module, checker_functions),
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m_objc_object_check_func(NULL)
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{
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}
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virtual
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~ObjcObjectChecker ()
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{
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}
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enum msgSend_type
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{
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eMsgSend = 0,
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eMsgSendSuper,
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eMsgSendSuper_stret,
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eMsgSend_fpret,
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eMsgSend_stret
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};
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std::map <llvm::Instruction *, msgSend_type> msgSend_types;
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private:
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bool InstrumentInstruction(llvm::Instruction *inst)
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{
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CallInst *call_inst = dyn_cast<CallInst>(inst);
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if (!call_inst)
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return false; // call_inst really shouldn't be NULL, because otherwise InspectInstruction wouldn't have registered it
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if (!m_objc_object_check_func)
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m_objc_object_check_func = BuildObjectCheckerFunc(m_checker_functions.m_objc_object_check->StartAddress());
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// id objc_msgSend(id theReceiver, SEL theSelector, ...)
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llvm::Value *target_object;
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llvm::Value *selector;
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switch (msgSend_types[inst])
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{
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case eMsgSend:
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case eMsgSend_fpret:
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target_object = call_inst->getArgOperand(0);
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selector = call_inst->getArgOperand(1);
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break;
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case eMsgSend_stret:
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target_object = call_inst->getArgOperand(1);
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selector = call_inst->getArgOperand(2);
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break;
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case eMsgSendSuper:
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case eMsgSendSuper_stret:
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return true;
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}
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// These objects should always be valid according to Sean Calannan
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assert (target_object);
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assert (selector);
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// Insert an instruction to cast the receiver id to int8_t*
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BitCastInst *bit_cast = new BitCastInst(target_object,
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GetI8PtrTy(),
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"",
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inst);
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// Insert an instruction to call the helper with the result
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llvm::Value *arg_array[2];
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arg_array[0] = bit_cast;
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arg_array[1] = selector;
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ArrayRef<llvm::Value*> args(arg_array, 2);
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CallInst::Create(m_objc_object_check_func,
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args,
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"",
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inst);
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return true;
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}
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bool InspectInstruction(llvm::Instruction &i)
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{
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Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
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CallInst *call_inst = dyn_cast<CallInst>(&i);
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if (call_inst)
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{
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// This metadata is set by IRForTarget::MaybeHandleCall().
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MDNode *metadata = call_inst->getMetadata("lldb.call.realName");
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if (!metadata)
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return true;
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if (metadata->getNumOperands() != 1)
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{
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if (log)
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log->Printf("Function call metadata has %d operands for [%p] %s",
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metadata->getNumOperands(),
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static_cast<void*>(call_inst),
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PrintValue(call_inst).c_str());
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return false;
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}
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MDString *real_name = dyn_cast<MDString>(metadata->getOperand(0));
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if (!real_name)
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{
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if (log)
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log->Printf("Function call metadata is not an MDString for [%p] %s",
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static_cast<void*>(call_inst),
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PrintValue(call_inst).c_str());
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return false;
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}
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std::string name_str = real_name->getString();
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const char* name_cstr = name_str.c_str();
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if (log)
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log->Printf("Found call to %s: %s\n", name_cstr, PrintValue(call_inst).c_str());
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if (name_str.find("objc_msgSend") == std::string::npos)
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return true;
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if (!strcmp(name_cstr, "objc_msgSend"))
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{
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RegisterInstruction(i);
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msgSend_types[&i] = eMsgSend;
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return true;
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}
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if (!strcmp(name_cstr, "objc_msgSend_stret"))
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{
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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;
|
|
}
|
|
|
|
llvm::Value *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()
|
|
{
|
|
}
|
|
|
|
bool
|
|
IRDynamicChecks::runOnModule(llvm::Module &M)
|
|
{
|
|
Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
|
|
|
|
llvm::Function* function = M.getFunction(StringRef(m_func_name.c_str()));
|
|
|
|
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.get())
|
|
{
|
|
ValidPointerChecker vpc(M, m_checker_functions);
|
|
|
|
if (!vpc.Inspect(*function))
|
|
return false;
|
|
|
|
if (!vpc.Instrument())
|
|
return false;
|
|
}
|
|
|
|
if (m_checker_functions.m_objc_object_check.get())
|
|
{
|
|
ObjcObjectChecker ooc(M, m_checker_functions);
|
|
|
|
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, NULL);
|
|
|
|
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;
|
|
}
|