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llvm-project/lldb/source/Expression/ClangExpressionParser.cpp
Sean Callanan e4ec90e990 Implemented a feature where the expression parser 
can avoid running the code in the target if the
expression's result is known and the expression
has no side effects.

Right now this feature is quite conservative in
its guess about side effects, and it only computes
integer results, but the machinery to make it more
sophisticated is there.

llvm-svn: 121952
2010-12-16 03:17:46 +00:00

724 lines
26 KiB
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//===-- ClangExpressionParser.cpp -------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "lldb/Expression/ClangExpressionParser.h"
#include "lldb/Core/ArchSpec.h"
#include "lldb/Core/DataBufferHeap.h"
#include "lldb/Core/Disassembler.h"
#include "lldb/Core/Stream.h"
#include "lldb/Core/StreamString.h"
#include "lldb/Expression/ClangASTSource.h"
#include "lldb/Expression/ClangExpression.h"
#include "lldb/Expression/IRDynamicChecks.h"
#include "lldb/Expression/IRForTarget.h"
#include "lldb/Expression/IRToDWARF.h"
#include "lldb/Expression/RecordingMemoryManager.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/Target.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/ExternalASTSource.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Basic/Version.h"
#include "clang/Checker/FrontendActions.h"
#include "clang/CodeGen/CodeGenAction.h"
#include "clang/CodeGen/ModuleBuilder.h"
#include "clang/Driver/CC1Options.h"
#include "clang/Driver/OptTable.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Frontend/CompilerInvocation.h"
#include "clang/Frontend/FrontendActions.h"
#include "clang/Frontend/FrontendDiagnostic.h"
#include "clang/Frontend/FrontendPluginRegistry.h"
#include "clang/Frontend/TextDiagnosticBuffer.h"
#include "clang/Frontend/TextDiagnosticPrinter.h"
#include "clang/Frontend/VerifyDiagnosticsClient.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Parse/ParseAST.h"
#include "clang/Rewrite/FrontendActions.h"
#include "clang/Sema/SemaConsumer.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ExecutionEngine/ExecutionEngine.h"
#include "llvm/ExecutionEngine/JIT.h"
#include "llvm/Module.h"
#include "llvm/LLVMContext.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/DynamicLibrary.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/Signals.h"
#include "llvm/Target/TargetRegistry.h"
#include "llvm/Target/TargetSelect.h"
using namespace clang;
using namespace llvm;
using namespace lldb_private;
//===----------------------------------------------------------------------===//
// Utility Methods for Clang
//===----------------------------------------------------------------------===//
std::string GetBuiltinIncludePath(const char *Argv0) {
llvm::sys::Path P =
llvm::sys::Path::GetMainExecutable(Argv0,
(void*)(intptr_t) GetBuiltinIncludePath);
if (!P.isEmpty()) {
P.eraseComponent(); // Remove /clang from foo/bin/clang
P.eraseComponent(); // Remove /bin from foo/bin
// Get foo/lib/clang/<version>/include
P.appendComponent("lib");
P.appendComponent("clang");
P.appendComponent(CLANG_VERSION_STRING);
P.appendComponent("include");
}
return P.str();
}
//===----------------------------------------------------------------------===//
// Main driver for Clang
//===----------------------------------------------------------------------===//
static void LLVMErrorHandler(void *UserData, const std::string &Message) {
Diagnostic &Diags = *static_cast<Diagnostic*>(UserData);
Diags.Report(diag::err_fe_error_backend) << Message;
// We cannot recover from llvm errors.
exit(1);
}
static FrontendAction *CreateFrontendBaseAction(CompilerInstance &CI) {
using namespace clang::frontend;
switch (CI.getFrontendOpts().ProgramAction) {
default:
llvm_unreachable("Invalid program action!");
case ASTDump: return new ASTDumpAction();
case ASTPrint: return new ASTPrintAction();
case ASTPrintXML: return new ASTPrintXMLAction();
case ASTView: return new ASTViewAction();
case BoostCon: return new BoostConAction();
case DumpRawTokens: return new DumpRawTokensAction();
case DumpTokens: return new DumpTokensAction();
case EmitAssembly: return new EmitAssemblyAction();
case EmitBC: return new EmitBCAction();
case EmitHTML: return new HTMLPrintAction();
case EmitLLVM: return new EmitLLVMAction();
case EmitLLVMOnly: return new EmitLLVMOnlyAction();
case EmitCodeGenOnly: return new EmitCodeGenOnlyAction();
case EmitObj: return new EmitObjAction();
case FixIt: return new FixItAction();
case GeneratePCH: return new GeneratePCHAction();
case GeneratePTH: return new GeneratePTHAction();
case InheritanceView: return new InheritanceViewAction();
case InitOnly: return new InitOnlyAction();
case ParseSyntaxOnly: return new SyntaxOnlyAction();
case PluginAction: {
for (FrontendPluginRegistry::iterator it =
FrontendPluginRegistry::begin(), ie = FrontendPluginRegistry::end();
it != ie; ++it) {
if (it->getName() == CI.getFrontendOpts().ActionName) {
llvm::OwningPtr<PluginASTAction> P(it->instantiate());
if (!P->ParseArgs(CI, CI.getFrontendOpts().PluginArgs))
return 0;
return P.take();
}
}
CI.getDiagnostics().Report(diag::err_fe_invalid_plugin_name)
<< CI.getFrontendOpts().ActionName;
return 0;
}
case PrintDeclContext: return new DeclContextPrintAction();
case PrintPreamble: return new PrintPreambleAction();
case PrintPreprocessedInput: return new PrintPreprocessedAction();
case RewriteMacros: return new RewriteMacrosAction();
case RewriteObjC: return new RewriteObjCAction();
case RewriteTest: return new RewriteTestAction();
case RunAnalysis: return new AnalysisAction();
case RunPreprocessorOnly: return new PreprocessOnlyAction();
}
}
static FrontendAction *CreateFrontendAction(CompilerInstance &CI) {
// Create the underlying action.
FrontendAction *Act = CreateFrontendBaseAction(CI);
if (!Act)
return 0;
// If there are any AST files to merge, create a frontend action
// adaptor to perform the merge.
if (!CI.getFrontendOpts().ASTMergeFiles.empty())
Act = new ASTMergeAction(Act, &CI.getFrontendOpts().ASTMergeFiles[0],
CI.getFrontendOpts().ASTMergeFiles.size());
return Act;
}
//===----------------------------------------------------------------------===//
// Implementation of ClangExpressionParser
//===----------------------------------------------------------------------===//
ClangExpressionParser::ClangExpressionParser(const char *target_triple,
ClangExpression &expr) :
m_expr(expr),
m_target_triple (),
m_compiler (),
m_code_generator (NULL),
m_execution_engine (),
m_jitted_functions ()
{
// Initialize targets first, so that --version shows registered targets.
static struct InitializeLLVM {
InitializeLLVM() {
llvm::InitializeAllTargets();
llvm::InitializeAllAsmPrinters();
}
} InitializeLLVM;
if (target_triple && target_triple[0])
m_target_triple = target_triple;
else
m_target_triple = llvm::sys::getHostTriple();
// 1. Create a new compiler instance.
m_compiler.reset(new CompilerInstance());
m_compiler->setLLVMContext(new LLVMContext());
// 2. Set options.
// Parse expressions as Objective C++ regardless of context.
// Our hook into Clang's lookup mechanism only works in C++.
m_compiler->getLangOpts().CPlusPlus = true;
m_compiler->getLangOpts().ObjC1 = true;
m_compiler->getLangOpts().ThreadsafeStatics = false;
m_compiler->getLangOpts().AccessControl = false; // Debuggers get universal access
m_compiler->getLangOpts().DollarIdents = true; // $ indicates a persistent variable name
// Set CodeGen options
m_compiler->getCodeGenOpts().EmitDeclMetadata = true;
m_compiler->getCodeGenOpts().InstrumentFunctions = false;
// Disable some warnings.
m_compiler->getDiagnosticOpts().Warnings.push_back("no-unused-value");
// Set the target triple.
m_compiler->getTargetOpts().Triple = m_target_triple;
// 3. Set up various important bits of infrastructure.
m_compiler->createDiagnostics(0, 0);
// Create the target instance.
m_compiler->setTarget(TargetInfo::CreateTargetInfo(m_compiler->getDiagnostics(),
m_compiler->getTargetOpts()));
assert (m_compiler->hasTarget());
// Inform the target of the language options
//
// FIXME: We shouldn't need to do this, the target should be immutable once
// created. This complexity should be lifted elsewhere.
m_compiler->getTarget().setForcedLangOptions(m_compiler->getLangOpts());
// 4. Set up the diagnostic buffer for reporting errors
m_compiler->getDiagnostics().setClient(new clang::TextDiagnosticBuffer);
// 5. Set up the source management objects inside the compiler
clang::FileSystemOptions file_system_options;
m_file_manager.reset(new clang::FileManager(file_system_options));
if (!m_compiler->hasSourceManager())
m_compiler->createSourceManager(*m_file_manager.get());
m_compiler->createFileManager();
m_compiler->createPreprocessor();
// 6. Most of this we get from the CompilerInstance, but we
// also want to give the context an ExternalASTSource.
m_selector_table.reset(new SelectorTable());
m_builtin_context.reset(new Builtin::Context(m_compiler->getTarget()));
std::auto_ptr<clang::ASTContext> ast_context(new ASTContext(m_compiler->getLangOpts(),
m_compiler->getSourceManager(),
m_compiler->getTarget(),
m_compiler->getPreprocessor().getIdentifierTable(),
*m_selector_table.get(),
*m_builtin_context.get(),
0));
ClangExpressionDeclMap *decl_map = m_expr.DeclMap();
if (decl_map)
{
OwningPtr<clang::ExternalASTSource> ast_source(new ClangASTSource(*ast_context, *decl_map));
ast_context->setExternalSource(ast_source);
}
m_compiler->setASTContext(ast_context.release());
std::string module_name("$__lldb_module");
m_code_generator.reset(CreateLLVMCodeGen(m_compiler->getDiagnostics(),
module_name,
m_compiler->getCodeGenOpts(),
m_compiler->getLLVMContext()));
}
ClangExpressionParser::~ClangExpressionParser()
{
}
unsigned
ClangExpressionParser::Parse (Stream &stream)
{
TextDiagnosticBuffer *diag_buf = static_cast<TextDiagnosticBuffer*>(m_compiler->getDiagnostics().getClient());
diag_buf->FlushDiagnostics (m_compiler->getDiagnostics());
MemoryBuffer *memory_buffer = MemoryBuffer::getMemBufferCopy(m_expr.Text(), __FUNCTION__);
FileID memory_buffer_file_id = m_compiler->getSourceManager().createMainFileIDForMemBuffer (memory_buffer);
diag_buf->BeginSourceFile(m_compiler->getLangOpts(), &m_compiler->getPreprocessor());
ASTConsumer *ast_transformer = m_expr.ASTTransformer(m_code_generator.get());
if (ast_transformer)
ParseAST(m_compiler->getPreprocessor(), ast_transformer, m_compiler->getASTContext());
else
ParseAST(m_compiler->getPreprocessor(), m_code_generator.get(), m_compiler->getASTContext());
diag_buf->EndSourceFile();
TextDiagnosticBuffer::const_iterator diag_iterator;
int num_errors = 0;
for (diag_iterator = diag_buf->warn_begin();
diag_iterator != diag_buf->warn_end();
++diag_iterator)
stream.Printf("warning: %s\n", (*diag_iterator).second.c_str());
num_errors = 0;
for (diag_iterator = diag_buf->err_begin();
diag_iterator != diag_buf->err_end();
++diag_iterator)
{
num_errors++;
stream.Printf("error: %s\n", (*diag_iterator).second.c_str());
}
for (diag_iterator = diag_buf->note_begin();
diag_iterator != diag_buf->note_end();
++diag_iterator)
stream.Printf("note: %s\n", (*diag_iterator).second.c_str());
return num_errors;
}
static bool FindFunctionInModule (std::string &mangled_name,
llvm::Module *module,
const char *orig_name)
{
for (llvm::Module::iterator fi = module->getFunctionList().begin(), fe = module->getFunctionList().end();
fi != fe;
++fi)
{
if (fi->getName().str().find(orig_name) != std::string::npos)
{
mangled_name = fi->getName().str();
return true;
}
}
return false;
}
Error
ClangExpressionParser::MakeDWARF ()
{
Error err;
llvm::Module *module = m_code_generator->GetModule();
if (!module)
{
err.SetErrorToGenericError();
err.SetErrorString("IR doesn't contain a module");
return err;
}
ClangExpressionVariableList *local_variables = m_expr.LocalVariables();
ClangExpressionDeclMap *decl_map = m_expr.DeclMap();
if (!local_variables)
{
err.SetErrorToGenericError();
err.SetErrorString("Can't convert an expression without a VariableList to DWARF");
return err;
}
if (!decl_map)
{
err.SetErrorToGenericError();
err.SetErrorString("Can't convert an expression without a DeclMap to DWARF");
return err;
}
std::string function_name;
if (!FindFunctionInModule(function_name, module, m_expr.FunctionName()))
{
err.SetErrorToGenericError();
err.SetErrorStringWithFormat("Couldn't find %s() in the module", m_expr.FunctionName());
return err;
}
IRToDWARF ir_to_dwarf(*local_variables, decl_map, m_expr.DwarfOpcodeStream(), function_name.c_str());
if (!ir_to_dwarf.runOnModule(*module))
{
err.SetErrorToGenericError();
err.SetErrorString("Couldn't convert the expression to DWARF");
return err;
}
err.Clear();
return err;
}
Error
ClangExpressionParser::MakeJIT (lldb::addr_t &func_addr,
lldb::addr_t &func_end,
ExecutionContext &exe_ctx,
lldb::ClangExpressionVariableSP *const_result)
{
lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
Error err;
llvm::Module *module = m_code_generator->ReleaseModule();
if (!module)
{
err.SetErrorToGenericError();
err.SetErrorString("IR doesn't contain a module");
return err;
}
// Find the actual name of the function (it's often mangled somehow)
std::string function_name;
if (!FindFunctionInModule(function_name, module, m_expr.FunctionName()))
{
err.SetErrorToGenericError();
err.SetErrorStringWithFormat("Couldn't find %s() in the module", m_expr.FunctionName());
return err;
}
else
{
if(log)
log->Printf("Found function %s for %s", function_name.c_str(), m_expr.FunctionName());
}
ClangExpressionDeclMap *decl_map = m_expr.DeclMap(); // result can be NULL
if (decl_map)
{
IRForTarget ir_for_target(decl_map,
m_expr.NeedsVariableResolution(),
const_result,
function_name.c_str());
if (!ir_for_target.runOnModule(*module))
{
err.SetErrorToGenericError();
err.SetErrorString("Couldn't convert the expression to DWARF");
return err;
}
if (m_expr.NeedsValidation() && exe_ctx.process->GetDynamicCheckers())
{
IRDynamicChecks ir_dynamic_checks(*exe_ctx.process->GetDynamicCheckers(), function_name.c_str());
if (!ir_dynamic_checks.runOnModule(*module))
{
err.SetErrorToGenericError();
err.SetErrorString("Couldn't add dynamic checks to the expression");
return err;
}
}
}
m_jit_mm = new RecordingMemoryManager();
std::string error_string;
llvm::TargetMachine::setRelocationModel(llvm::Reloc::PIC_);
m_execution_engine.reset(llvm::ExecutionEngine::createJIT (module,
&error_string,
m_jit_mm,
CodeGenOpt::Less,
true,
CodeModel::Small));
if (!m_execution_engine.get())
{
err.SetErrorToGenericError();
err.SetErrorStringWithFormat("Couldn't JIT the function: %s", error_string.c_str());
return err;
}
m_execution_engine->DisableLazyCompilation();
llvm::Function *function = module->getFunction (function_name.c_str());
// We don't actually need the function pointer here, this just forces it to get resolved.
void *fun_ptr = m_execution_engine->getPointerToFunction(function);
// Errors usually cause failures in the JIT, but if we're lucky we get here.
if (!fun_ptr)
{
err.SetErrorToGenericError();
err.SetErrorString("Couldn't JIT the function");
return err;
}
m_jitted_functions.push_back (ClangExpressionParser::JittedFunction(function_name.c_str(), (lldb::addr_t)fun_ptr));
ExecutionContext &exc_context(exe_ctx);
if (exc_context.process == NULL)
{
err.SetErrorToGenericError();
err.SetErrorString("Couldn't write the JIT compiled code into the target because there is no target");
return err;
}
// Look over the regions allocated for the function compiled. The JIT
// tries to allocate the functions & stubs close together, so we should try to
// write them that way too...
// For now I only write functions with no stubs, globals, exception tables,
// etc. So I only need to write the functions.
size_t alloc_size = 0;
std::map<uint8_t *, uint8_t *>::iterator fun_pos = m_jit_mm->m_functions.begin();
std::map<uint8_t *, uint8_t *>::iterator fun_end = m_jit_mm->m_functions.end();
for (; fun_pos != fun_end; ++fun_pos)
alloc_size += (*fun_pos).second - (*fun_pos).first;
Error alloc_error;
lldb::addr_t target_addr = exc_context.process->AllocateMemory (alloc_size, lldb::ePermissionsReadable|lldb::ePermissionsExecutable, alloc_error);
if (target_addr == LLDB_INVALID_ADDRESS)
{
err.SetErrorToGenericError();
err.SetErrorStringWithFormat("Couldn't allocate memory for the JITted function: %s", alloc_error.AsCString("unknown error"));
return err;
}
lldb::addr_t cursor = target_addr;
for (fun_pos = m_jit_mm->m_functions.begin(); fun_pos != fun_end; fun_pos++)
{
lldb::addr_t lstart = (lldb::addr_t) (*fun_pos).first;
lldb::addr_t lend = (lldb::addr_t) (*fun_pos).second;
size_t size = lend - lstart;
Error write_error;
if (exc_context.process->WriteMemory(cursor, (void *) lstart, size, write_error) != size)
{
err.SetErrorToGenericError();
err.SetErrorStringWithFormat("Couldn't copy JITted function into the target: %s", write_error.AsCString("unknown error"));
return err;
}
m_jit_mm->AddToLocalToRemoteMap (lstart, size, cursor);
cursor += size;
}
std::vector<JittedFunction>::iterator pos, end = m_jitted_functions.end();
for (pos = m_jitted_functions.begin(); pos != end; pos++)
{
(*pos).m_remote_addr = m_jit_mm->GetRemoteAddressForLocal ((*pos).m_local_addr);
if (!(*pos).m_name.compare(function_name.c_str()))
{
func_end = m_jit_mm->GetRemoteRangeForLocal ((*pos).m_local_addr).second;
func_addr = (*pos).m_remote_addr;
}
}
if (log)
{
log->Printf("Code can be run in the target.");
StreamString disassembly_stream;
Error err = DisassembleFunction(disassembly_stream, exe_ctx);
if (!err.Success())
{
log->Printf("Couldn't disassemble function : %s", err.AsCString("unknown error"));
}
else
{
log->Printf("Function disassembly:\n%s", disassembly_stream.GetData());
}
}
err.Clear();
return err;
}
Error
ClangExpressionParser::DisassembleFunction (Stream &stream, ExecutionContext &exe_ctx)
{
lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
const char *name = m_expr.FunctionName();
Error ret;
ret.Clear();
lldb::addr_t func_local_addr = LLDB_INVALID_ADDRESS;
lldb::addr_t func_remote_addr = LLDB_INVALID_ADDRESS;
std::vector<JittedFunction>::iterator pos, end = m_jitted_functions.end();
for (pos = m_jitted_functions.begin(); pos < end; pos++)
{
if (strstr(pos->m_name.c_str(), name))
{
func_local_addr = pos->m_local_addr;
func_remote_addr = pos->m_remote_addr;
}
}
if (func_local_addr == LLDB_INVALID_ADDRESS)
{
ret.SetErrorToGenericError();
ret.SetErrorStringWithFormat("Couldn't find function %s for disassembly", name);
return ret;
}
if(log)
log->Printf("Found function, has local address 0x%llx and remote address 0x%llx", (uint64_t)func_local_addr, (uint64_t)func_remote_addr);
std::pair <lldb::addr_t, lldb::addr_t> func_range;
func_range = m_jit_mm->GetRemoteRangeForLocal(func_local_addr);
if (func_range.first == 0 && func_range.second == 0)
{
ret.SetErrorToGenericError();
ret.SetErrorStringWithFormat("Couldn't find code range for function %s", name);
return ret;
}
if(log)
log->Printf("Function's code range is [0x%llx-0x%llx]", func_range.first, func_range.second);
if (!exe_ctx.target)
{
ret.SetErrorToGenericError();
ret.SetErrorString("Couldn't find the target");
}
lldb::DataBufferSP buffer_sp(new DataBufferHeap(func_range.second - func_remote_addr, 0));
Error err;
exe_ctx.process->ReadMemory(func_remote_addr, buffer_sp->GetBytes(), buffer_sp->GetByteSize(), err);
if (!err.Success())
{
ret.SetErrorToGenericError();
ret.SetErrorStringWithFormat("Couldn't read from process: %s", err.AsCString("unknown error"));
return ret;
}
ArchSpec arch(exe_ctx.target->GetArchitecture());
Disassembler *disassembler = Disassembler::FindPlugin(arch);
if (disassembler == NULL)
{
ret.SetErrorToGenericError();
ret.SetErrorStringWithFormat("Unable to find disassembler plug-in for %s architecture.", arch.AsCString());
return ret;
}
if (!exe_ctx.process)
{
ret.SetErrorToGenericError();
ret.SetErrorString("Couldn't find the process");
return ret;
}
DataExtractor extractor(buffer_sp,
exe_ctx.process->GetByteOrder(),
exe_ctx.target->GetArchitecture().GetAddressByteSize());
if (log)
{
log->Printf("Function data has contents:");
extractor.PutToLog (log.get(),
0,
extractor.GetByteSize(),
func_remote_addr,
16,
DataExtractor::TypeUInt8);
}
disassembler->DecodeInstructions (Address (NULL, func_remote_addr), extractor, 0, UINT32_MAX);
InstructionList &instruction_list = disassembler->GetInstructionList();
uint32_t bytes_offset = 0;
for (uint32_t instruction_index = 0, num_instructions = instruction_list.GetSize();
instruction_index < num_instructions;
++instruction_index)
{
Instruction *instruction = instruction_list.GetInstructionAtIndex(instruction_index).get();
instruction->Dump (&stream,
true,
&extractor,
bytes_offset,
&exe_ctx,
true);
stream.PutChar('\n');
bytes_offset += instruction->GetByteSize();
}
return ret;
}
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