OSchip
/
llvm-project
mirror of https://github.com/THU-DSP-LAB/llvm-project.git
13
0
Fork 6
Code Issues Packages Projects Releases Wiki Activity
llvm-project/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp

2187 lines
70 KiB
C++
Raw Blame History

//===-- IRForTarget.cpp -----------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "IRForTarget.h"
#include "ClangExpressionDeclMap.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/ValueSymbolTable.h"
#include "clang/AST/ASTContext.h"
#include "lldb/Core/ConstString.h"
#include "lldb/Core/DataBufferHeap.h"
#include "lldb/Core/Log.h"
#include "lldb/Core/Scalar.h"
#include "lldb/Core/StreamString.h"
#include "lldb/Core/dwarf.h"
#include "lldb/Expression/IRExecutionUnit.h"
#include "lldb/Expression/IRInterpreter.h"
#include "lldb/Host/Endian.h"
#include "lldb/Symbol/ClangASTContext.h"
#include "lldb/Symbol/ClangUtil.h"
#include "lldb/Symbol/CompilerType.h"
#include <map>
using namespace llvm;
static char ID;
IRForTarget::FunctionValueCache::FunctionValueCache(Maker const &maker) :
m_maker(maker),
m_values()
{
}
IRForTarget::FunctionValueCache::~FunctionValueCache()
{
}
llvm::Value *
IRForTarget::FunctionValueCache::GetValue(llvm::Function *function)
{
if (!m_values.count(function))
{
llvm::Value *ret = m_maker(function);
m_values[function] = ret;
return ret;
}
return m_values[function];
}
static llvm::Value *
FindEntryInstruction (llvm::Function *function)
{
if (function->empty())
return NULL;
return function->getEntryBlock().getFirstNonPHIOrDbg();
}
IRForTarget::IRForTarget (lldb_private::ClangExpressionDeclMap *decl_map,
bool resolve_vars,
lldb_private::IRExecutionUnit &execution_unit,
lldb_private::Stream *error_stream,
const char *func_name) :
ModulePass(ID),
m_resolve_vars(resolve_vars),
m_func_name(func_name),
m_module(NULL),
m_decl_map(decl_map),
m_CFStringCreateWithBytes(NULL),
m_sel_registerName(NULL),
m_intptr_ty(NULL),
m_error_stream(error_stream),
m_execution_unit(execution_unit),
m_result_store(NULL),
m_result_is_pointer(false),
m_reloc_placeholder(NULL),
m_entry_instruction_finder (FindEntryInstruction)
{
}
/* Handy utility functions used at several places in the code */
static std::string
PrintValue(const Value *value, bool truncate = false)
{
std::string s;
if (value)
{
raw_string_ostream rso(s);
value->print(rso);
rso.flush();
if (truncate)
s.resize(s.length() - 1);
}
return s;
}
static std::string
PrintType(const llvm::Type *type, bool truncate = false)
{
std::string s;
raw_string_ostream rso(s);
type->print(rso);
rso.flush();
if (truncate)
s.resize(s.length() - 1);
return s;
}
IRForTarget::~IRForTarget()
{
}
bool
IRForTarget::FixFunctionLinkage(llvm::Function &llvm_function)
{
llvm_function.setLinkage(GlobalValue::ExternalLinkage);
return true;
}
clang::NamedDecl *
IRForTarget::DeclForGlobal (const GlobalValue *global_val, Module *module)
{
NamedMDNode *named_metadata = module->getNamedMetadata("clang.global.decl.ptrs");
if (!named_metadata)
return NULL;
unsigned num_nodes = named_metadata->getNumOperands();
unsigned node_index;
for (node_index = 0;
node_index < num_nodes;
++node_index)
{
llvm::MDNode *metadata_node = dyn_cast<llvm::MDNode>(named_metadata->getOperand(node_index));
if (!metadata_node)
return NULL;
if (metadata_node->getNumOperands() != 2)
continue;
if (mdconst::dyn_extract_or_null<GlobalValue>(metadata_node->getOperand(0)) != global_val)
continue;
ConstantInt *constant_int = mdconst::dyn_extract<ConstantInt>(metadata_node->getOperand(1));
if (!constant_int)
return NULL;
uintptr_t ptr = constant_int->getZExtValue();
return reinterpret_cast<clang::NamedDecl *>(ptr);
}
return NULL;
}
clang::NamedDecl *
IRForTarget::DeclForGlobal (GlobalValue *global_val)
{
return DeclForGlobal(global_val, m_module);
}
bool
IRForTarget::CreateResultVariable (llvm::Function &llvm_function)
{
lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
if (!m_resolve_vars)
return true;
// Find the result variable. If it doesn't exist, we can give up right here.
ValueSymbolTable& value_symbol_table = m_module->getValueSymbolTable();
std::string result_name_str;
const char *result_name = NULL;
for (ValueSymbolTable::iterator vi = value_symbol_table.begin(), ve = value_symbol_table.end();
vi != ve;
++vi)
{
result_name_str = vi->first().str();
const char *value_name = result_name_str.c_str();
if (strstr(value_name, "$__lldb_expr_result_ptr") &&
strncmp(value_name, "_ZGV", 4))
{
result_name = value_name;
m_result_is_pointer = true;
break;
}
if (strstr(value_name, "$__lldb_expr_result") &&
strncmp(value_name, "_ZGV", 4))
{
result_name = value_name;
m_result_is_pointer = false;
break;
}
}
if (!result_name)
{
if (log)
log->PutCString("Couldn't find result variable");
return true;
}
if (log)
log->Printf("Result name: \"%s\"", result_name);
Value *result_value = m_module->getNamedValue(result_name);
if (!result_value)
{
if (log)
log->PutCString("Result variable had no data");
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Result variable's name (%s) exists, but not its definition\n", result_name);
return false;
}
if (log)
log->Printf("Found result in the IR: \"%s\"", PrintValue(result_value, false).c_str());
GlobalVariable *result_global = dyn_cast<GlobalVariable>(result_value);
if (!result_global)
{
if (log)
log->PutCString("Result variable isn't a GlobalVariable");
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Result variable (%s) is defined, but is not a global variable\n", result_name);
return false;
}
clang::NamedDecl *result_decl = DeclForGlobal (result_global);
if (!result_decl)
{
if (log)
log->PutCString("Result variable doesn't have a corresponding Decl");
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Result variable (%s) does not have a corresponding Clang entity\n", result_name);
return false;
}
if (log)
{
std::string decl_desc_str;
raw_string_ostream decl_desc_stream(decl_desc_str);
result_decl->print(decl_desc_stream);
decl_desc_stream.flush();
log->Printf("Found result decl: \"%s\"", decl_desc_str.c_str());
}
clang::VarDecl *result_var = dyn_cast<clang::VarDecl>(result_decl);
if (!result_var)
{
if (log)
log->PutCString("Result variable Decl isn't a VarDecl");
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Result variable (%s)'s corresponding Clang entity isn't a variable\n", result_name);
return false;
}
// Get the next available result name from m_decl_map and create the persistent
// variable for it
// If the result is an Lvalue, it is emitted as a pointer; see
// ASTResultSynthesizer::SynthesizeBodyResult.
if (m_result_is_pointer)
{
clang::QualType pointer_qual_type = result_var->getType();
const clang::Type *pointer_type = pointer_qual_type.getTypePtr();
const clang::PointerType *pointer_pointertype = pointer_type->getAs<clang::PointerType>();
const clang::ObjCObjectPointerType *pointer_objcobjpointertype = pointer_type->getAs<clang::ObjCObjectPointerType>();
if (pointer_pointertype)
{
clang::QualType element_qual_type = pointer_pointertype->getPointeeType();
m_result_type = lldb_private::TypeFromParser(element_qual_type.getAsOpaquePtr(),
lldb_private::ClangASTContext::GetASTContext(&result_decl->getASTContext()));
}
else if (pointer_objcobjpointertype)
{
clang::QualType element_qual_type = clang::QualType(pointer_objcobjpointertype->getObjectType(), 0);
m_result_type = lldb_private::TypeFromParser(element_qual_type.getAsOpaquePtr(),
lldb_private::ClangASTContext::GetASTContext(&result_decl->getASTContext()));
}
else
{
if (log)
log->PutCString("Expected result to have pointer type, but it did not");
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Lvalue result (%s) is not a pointer variable\n", result_name);
return false;
}
}
else
{
m_result_type = lldb_private::TypeFromParser(result_var->getType().getAsOpaquePtr(),
lldb_private::ClangASTContext::GetASTContext(&result_decl->getASTContext()));
}
lldb::TargetSP target_sp (m_execution_unit.GetTarget());
lldb_private::ExecutionContext exe_ctx (target_sp, true);
if (m_result_type.GetBitSize(exe_ctx.GetBestExecutionContextScope()) == 0)
{
lldb_private::StreamString type_desc_stream;
m_result_type.DumpTypeDescription(&type_desc_stream);
if (log)
log->Printf("Result type has size 0");
if (m_error_stream)
m_error_stream->Printf("Error [IRForTarget]: Size of result type '%s' couldn't be determined\n",
type_desc_stream.GetData());
return false;
}
if (log)
{
lldb_private::StreamString type_desc_stream;
m_result_type.DumpTypeDescription(&type_desc_stream);
log->Printf("Result decl type: \"%s\"", type_desc_stream.GetData());
}
m_result_name = lldb_private::ConstString("$RESULT_NAME");
if (log)
log->Printf("Creating a new result global: \"%s\" with size 0x%" PRIx64,
m_result_name.GetCString(),
m_result_type.GetByteSize(nullptr));
// Construct a new result global and set up its metadata
GlobalVariable *new_result_global = new GlobalVariable((*m_module),
result_global->getType()->getElementType(),
false, /* not constant */
GlobalValue::ExternalLinkage,
NULL, /* no initializer */
m_result_name.GetCString ());
// It's too late in compilation to create a new VarDecl for this, but we don't
// need to. We point the metadata at the old VarDecl. This creates an odd
// anomaly: a variable with a Value whose name is something like $0 and a
// Decl whose name is $__lldb_expr_result. This condition is handled in
// ClangExpressionDeclMap::DoMaterialize, and the name of the variable is
// fixed up.
ConstantInt *new_constant_int = ConstantInt::get(llvm::Type::getInt64Ty(m_module->getContext()),
reinterpret_cast<uint64_t>(result_decl),
false);
llvm::Metadata *values[2];
values[0] = ConstantAsMetadata::get(new_result_global);
values[1] = ConstantAsMetadata::get(new_constant_int);
ArrayRef<Metadata *> value_ref(values, 2);
MDNode *persistent_global_md = MDNode::get(m_module->getContext(), value_ref);
NamedMDNode *named_metadata = m_module->getNamedMetadata("clang.global.decl.ptrs");
named_metadata->addOperand(persistent_global_md);
if (log)
log->Printf("Replacing \"%s\" with \"%s\"",
PrintValue(result_global).c_str(),
PrintValue(new_result_global).c_str());
if (result_global->use_empty())
{
// We need to synthesize a store for this variable, because otherwise
// there's nothing to put into its equivalent persistent variable.
BasicBlock &entry_block(llvm_function.getEntryBlock());
Instruction *first_entry_instruction(entry_block.getFirstNonPHIOrDbg());
if (!first_entry_instruction)
return false;
if (!result_global->hasInitializer())
{
if (log)
log->Printf("Couldn't find initializer for unused variable");
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Result variable (%s) has no writes and no initializer\n", result_name);
return false;
}
Constant *initializer = result_global->getInitializer();
StoreInst *synthesized_store = new StoreInst(initializer,
new_result_global,
first_entry_instruction);
if (log)
log->Printf("Synthesized result store \"%s\"\n", PrintValue(synthesized_store).c_str());
}
else
{
result_global->replaceAllUsesWith(new_result_global);
}
if (!m_decl_map->AddPersistentVariable(result_decl,
m_result_name,
m_result_type,
true,
m_result_is_pointer))
return false;
result_global->eraseFromParent();
return true;
}
bool
IRForTarget::RewriteObjCConstString (llvm::GlobalVariable *ns_str,
llvm::GlobalVariable *cstr)
{
lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
Type *ns_str_ty = ns_str->getType();
Type *i8_ptr_ty = Type::getInt8PtrTy(m_module->getContext());
Type *i32_ty = Type::getInt32Ty(m_module->getContext());
Type *i8_ty = Type::getInt8Ty(m_module->getContext());
if (!m_CFStringCreateWithBytes)
{
lldb::addr_t CFStringCreateWithBytes_addr;
static lldb_private::ConstString g_CFStringCreateWithBytes_str ("CFStringCreateWithBytes");
CFStringCreateWithBytes_addr = m_execution_unit.FindSymbol (g_CFStringCreateWithBytes_str);
if (CFStringCreateWithBytes_addr == LLDB_INVALID_ADDRESS)
{
if (log)
log->PutCString("Couldn't find CFStringCreateWithBytes in the target");
if (m_error_stream)
m_error_stream->Printf("Error [IRForTarget]: Rewriting an Objective-C constant string requires CFStringCreateWithBytes\n");
return false;
}
if (log)
log->Printf("Found CFStringCreateWithBytes at 0x%" PRIx64, CFStringCreateWithBytes_addr);
// Build the function type:
//
// CFStringRef CFStringCreateWithBytes (
// CFAllocatorRef alloc,
// const UInt8 *bytes,
// CFIndex numBytes,
// CFStringEncoding encoding,
// Boolean isExternalRepresentation
// );
//
// We make the following substitutions:
//
// CFStringRef -> i8*
// CFAllocatorRef -> i8*
// UInt8 * -> i8*
// CFIndex -> long (i32 or i64, as appropriate; we ask the module for its pointer size for now)
// CFStringEncoding -> i32
// Boolean -> i8
Type *arg_type_array[5];
arg_type_array[0] = i8_ptr_ty;
arg_type_array[1] = i8_ptr_ty;
arg_type_array[2] = m_intptr_ty;
arg_type_array[3] = i32_ty;
arg_type_array[4] = i8_ty;
ArrayRef<Type *> CFSCWB_arg_types(arg_type_array, 5);
llvm::Type *CFSCWB_ty = FunctionType::get(ns_str_ty, CFSCWB_arg_types, false);
// Build the constant containing the pointer to the function
PointerType *CFSCWB_ptr_ty = PointerType::getUnqual(CFSCWB_ty);
Constant *CFSCWB_addr_int = ConstantInt::get(m_intptr_ty, CFStringCreateWithBytes_addr, false);
m_CFStringCreateWithBytes = ConstantExpr::getIntToPtr(CFSCWB_addr_int, CFSCWB_ptr_ty);
}
ConstantDataSequential *string_array = NULL;
if (cstr)
string_array = dyn_cast<ConstantDataSequential>(cstr->getInitializer());
Constant *alloc_arg = Constant::getNullValue(i8_ptr_ty);
Constant *bytes_arg = cstr ? ConstantExpr::getBitCast(cstr, i8_ptr_ty) : Constant::getNullValue(i8_ptr_ty);
Constant *numBytes_arg = ConstantInt::get(m_intptr_ty, cstr ? string_array->getNumElements() - 1 : 0, false);
Constant *encoding_arg = ConstantInt::get(i32_ty, 0x0600, false); /* 0x0600 is kCFStringEncodingASCII */
Constant *isExternal_arg = ConstantInt::get(i8_ty, 0x0, false); /* 0x0 is false */
Value *argument_array[5];
argument_array[0] = alloc_arg;
argument_array[1] = bytes_arg;
argument_array[2] = numBytes_arg;
argument_array[3] = encoding_arg;
argument_array[4] = isExternal_arg;
ArrayRef <Value *> CFSCWB_arguments(argument_array, 5);
FunctionValueCache CFSCWB_Caller ([this, &CFSCWB_arguments] (llvm::Function *function)->llvm::Value * {
return CallInst::Create(m_CFStringCreateWithBytes,
CFSCWB_arguments,
"CFStringCreateWithBytes",
llvm::cast<Instruction>(m_entry_instruction_finder.GetValue(function)));
});
if (!UnfoldConstant(ns_str, CFSCWB_Caller, m_entry_instruction_finder))
{
if (log)
log->PutCString("Couldn't replace the NSString with the result of the call");
if (m_error_stream)
m_error_stream->Printf("Error [IRForTarget]: Couldn't replace an Objective-C constant string with a dynamic string\n");
return false;
}
ns_str->eraseFromParent();
return true;
}
bool
IRForTarget::RewriteObjCConstStrings()
{
lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
ValueSymbolTable& value_symbol_table = m_module->getValueSymbolTable();
for (ValueSymbolTable::iterator vi = value_symbol_table.begin(), ve = value_symbol_table.end();
vi != ve;
++vi)
{
std::string value_name = vi->first().str();
const char *value_name_cstr = value_name.c_str();
if (strstr(value_name_cstr, "_unnamed_cfstring_"))
{
Value *nsstring_value = vi->second;
GlobalVariable *nsstring_global = dyn_cast<GlobalVariable>(nsstring_value);
if (!nsstring_global)
{
if (log)
log->PutCString("NSString variable is not a GlobalVariable");
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: An Objective-C constant string is not a global variable\n");
return false;
}
if (!nsstring_global->hasInitializer())
{
if (log)
log->PutCString("NSString variable does not have an initializer");
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: An Objective-C constant string does not have an initializer\n");
return false;
}
ConstantStruct *nsstring_struct = dyn_cast<ConstantStruct>(nsstring_global->getInitializer());
if (!nsstring_struct)
{
if (log)
log->PutCString("NSString variable's initializer is not a ConstantStruct");
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: An Objective-C constant string is not a structure constant\n");
return false;
}
// We expect the following structure:
//
// struct {
// int *isa;
// int flags;
// char *str;
// long length;
// };
if (nsstring_struct->getNumOperands() != 4)
{
if (log)
log->Printf("NSString variable's initializer structure has an unexpected number of members. Should be 4, is %d", nsstring_struct->getNumOperands());
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: The struct for an Objective-C constant string is not as expected\n");
return false;
}
Constant *nsstring_member = nsstring_struct->getOperand(2);
if (!nsstring_member)
{
if (log)
log->PutCString("NSString initializer's str element was empty");
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: An Objective-C constant string does not have a string initializer\n");
return false;
}
ConstantExpr *nsstring_expr = dyn_cast<ConstantExpr>(nsstring_member);
if (!nsstring_expr)
{
if (log)
log->PutCString("NSString initializer's str element is not a ConstantExpr");
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: An Objective-C constant string's string initializer is not constant\n");
return false;
}
if (nsstring_expr->getOpcode() != Instruction::GetElementPtr)
{
if (log)
log->Printf("NSString initializer's str element is not a GetElementPtr expression, it's a %s", nsstring_expr->getOpcodeName());
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: An Objective-C constant string's string initializer is not an array\n");
return false;
}
Constant *nsstring_cstr = nsstring_expr->getOperand(0);
GlobalVariable *cstr_global = dyn_cast<GlobalVariable>(nsstring_cstr);
if (!cstr_global)
{
if (log)
log->PutCString("NSString initializer's str element is not a GlobalVariable");
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: An Objective-C constant string's string initializer doesn't point to a global\n");
return false;
}
if (!cstr_global->hasInitializer())
{
if (log)
log->PutCString("NSString initializer's str element does not have an initializer");
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: An Objective-C constant string's string initializer doesn't point to initialized data\n");
return false;
}
/*
if (!cstr_array)
{
if (log)
log->PutCString("NSString initializer's str element is not a ConstantArray");
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: An Objective-C constant string's string initializer doesn't point to an array\n");
return false;
}
if (!cstr_array->isCString())
{
if (log)
log->PutCString("NSString initializer's str element is not a C string array");
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: An Objective-C constant string's string initializer doesn't point to a C string\n");
return false;
}
*/
ConstantDataArray *cstr_array = dyn_cast<ConstantDataArray>(cstr_global->getInitializer());
if (log)
{
if (cstr_array)
log->Printf("Found NSString constant %s, which contains \"%s\"", value_name_cstr, cstr_array->getAsString().str().c_str());
else
log->Printf("Found NSString constant %s, which contains \"\"", value_name_cstr);
}
if (!cstr_array)
cstr_global = NULL;
if (!RewriteObjCConstString(nsstring_global, cstr_global))
{
if (log)
log->PutCString("Error rewriting the constant string");
// We don't print an error message here because RewriteObjCConstString has done so for us.
return false;
}
}
}
for (ValueSymbolTable::iterator vi = value_symbol_table.begin(), ve = value_symbol_table.end();
vi != ve;
++vi)
{
std::string value_name = vi->first().str();
const char *value_name_cstr = value_name.c_str();
if (!strcmp(value_name_cstr, "__CFConstantStringClassReference"))
{
GlobalVariable *gv = dyn_cast<GlobalVariable>(vi->second);
if (!gv)
{
if (log)
log->PutCString("__CFConstantStringClassReference is not a global variable");
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Found a CFConstantStringClassReference, but it is not a global object\n");
return false;
}
gv->eraseFromParent();
break;
}
}
return true;
}
static bool IsObjCSelectorRef (Value *value)
{
GlobalVariable *global_variable = dyn_cast<GlobalVariable>(value);
if (!global_variable || !global_variable->hasName() || !global_variable->getName().startswith("OBJC_SELECTOR_REFERENCES_"))
return false;
return true;
}
// This function does not report errors; its callers are responsible.
bool
IRForTarget::RewriteObjCSelector (Instruction* selector_load)
{
lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
LoadInst *load = dyn_cast<LoadInst>(selector_load);
if (!load)
return false;
// Unpack the message name from the selector. In LLVM IR, an objc_msgSend gets represented as
//
// %tmp = load i8** @"OBJC_SELECTOR_REFERENCES_" ; <i8*>
// %call = call i8* (i8*, i8*, ...)* @objc_msgSend(i8* %obj, i8* %tmp, ...) ; <i8*>
//
// where %obj is the object pointer and %tmp is the selector.
//
// @"OBJC_SELECTOR_REFERENCES_" is a pointer to a character array called @"\01L_OBJC_llvm_moduleETH_VAR_NAllvm_moduleE_".
// @"\01L_OBJC_llvm_moduleETH_VAR_NAllvm_moduleE_" contains the string.
// Find the pointer's initializer (a ConstantExpr with opcode GetElementPtr) and get the string from its target
GlobalVariable *_objc_selector_references_ = dyn_cast<GlobalVariable>(load->getPointerOperand());
if (!_objc_selector_references_ || !_objc_selector_references_->hasInitializer())
return false;
Constant *osr_initializer = _objc_selector_references_->getInitializer();
ConstantExpr *osr_initializer_expr = dyn_cast<ConstantExpr>(osr_initializer);
if (!osr_initializer_expr || osr_initializer_expr->getOpcode() != Instruction::GetElementPtr)
return false;
Value *osr_initializer_base = osr_initializer_expr->getOperand(0);
if (!osr_initializer_base)
return false;
// Find the string's initializer (a ConstantArray) and get the string from it
GlobalVariable *_objc_meth_var_name_ = dyn_cast<GlobalVariable>(osr_initializer_base);
if (!_objc_meth_var_name_ || !_objc_meth_var_name_->hasInitializer())
return false;
Constant *omvn_initializer = _objc_meth_var_name_->getInitializer();
ConstantDataArray *omvn_initializer_array = dyn_cast<ConstantDataArray>(omvn_initializer);
if (!omvn_initializer_array->isString())
return false;
std::string omvn_initializer_string = omvn_initializer_array->getAsString();
if (log)
log->Printf("Found Objective-C selector reference \"%s\"", omvn_initializer_string.c_str());
// Construct a call to sel_registerName
if (!m_sel_registerName)
{
lldb::addr_t sel_registerName_addr;
static lldb_private::ConstString g_sel_registerName_str ("sel_registerName");
sel_registerName_addr = m_execution_unit.FindSymbol (g_sel_registerName_str);
if (sel_registerName_addr == LLDB_INVALID_ADDRESS)
return false;
if (log)
log->Printf("Found sel_registerName at 0x%" PRIx64, sel_registerName_addr);
// Build the function type: struct objc_selector *sel_registerName(uint8_t*)
// The below code would be "more correct," but in actuality what's required is uint8_t*
//Type *sel_type = StructType::get(m_module->getContext());
//Type *sel_ptr_type = PointerType::getUnqual(sel_type);
Type *sel_ptr_type = Type::getInt8PtrTy(m_module->getContext());
Type *type_array[1];
type_array[0] = llvm::Type::getInt8PtrTy(m_module->getContext());
ArrayRef<Type *> srN_arg_types(type_array, 1);
llvm::Type *srN_type = FunctionType::get(sel_ptr_type, srN_arg_types, false);
// Build the constant containing the pointer to the function
PointerType *srN_ptr_ty = PointerType::getUnqual(srN_type);
Constant *srN_addr_int = ConstantInt::get(m_intptr_ty, sel_registerName_addr, false);
m_sel_registerName = ConstantExpr::getIntToPtr(srN_addr_int, srN_ptr_ty);
}
Value *argument_array[1];
Constant *omvn_pointer = ConstantExpr::getBitCast(_objc_meth_var_name_, Type::getInt8PtrTy(m_module->getContext()));
argument_array[0] = omvn_pointer;
ArrayRef<Value *> srN_arguments(argument_array, 1);
CallInst *srN_call = CallInst::Create(m_sel_registerName,
srN_arguments,
"sel_registerName",
selector_load);
// Replace the load with the call in all users
selector_load->replaceAllUsesWith(srN_call);
selector_load->eraseFromParent();
return true;
}
bool
IRForTarget::RewriteObjCSelectors (BasicBlock &basic_block)
{
lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
BasicBlock::iterator ii;
typedef SmallVector <Instruction*, 2> InstrList;
typedef InstrList::iterator InstrIterator;
InstrList selector_loads;
for (ii = basic_block.begin();
ii != basic_block.end();
++ii)
{
Instruction &inst = *ii;
if (LoadInst *load = dyn_cast<LoadInst>(&inst))
if (IsObjCSelectorRef(load->getPointerOperand()))
selector_loads.push_back(&inst);
}
InstrIterator iter;
for (iter = selector_loads.begin();
iter != selector_loads.end();
++iter)
{
if (!RewriteObjCSelector(*iter))
{
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Couldn't change a static reference to an Objective-C selector to a dynamic reference\n");
if (log)
log->PutCString("Couldn't rewrite a reference to an Objective-C selector");
return false;
}
}
return true;
}
// This function does not report errors; its callers are responsible.
bool
IRForTarget::RewritePersistentAlloc (llvm::Instruction *persistent_alloc)
{
lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
AllocaInst *alloc = dyn_cast<AllocaInst>(persistent_alloc);
MDNode *alloc_md = alloc->getMetadata("clang.decl.ptr");
if (!alloc_md || !alloc_md->getNumOperands())
return false;
ConstantInt *constant_int = mdconst::dyn_extract<ConstantInt>(alloc_md->getOperand(0));
if (!constant_int)
return false;
// We attempt to register this as a new persistent variable with the DeclMap.
uintptr_t ptr = constant_int->getZExtValue();
clang::VarDecl *decl = reinterpret_cast<clang::VarDecl *>(ptr);
lldb_private::TypeFromParser result_decl_type (decl->getType().getAsOpaquePtr(),
lldb_private::ClangASTContext::GetASTContext(&decl->getASTContext()));
StringRef decl_name (decl->getName());
lldb_private::ConstString persistent_variable_name (decl_name.data(), decl_name.size());
if (!m_decl_map->AddPersistentVariable(decl, persistent_variable_name, result_decl_type, false, false))
return false;
GlobalVariable *persistent_global = new GlobalVariable((*m_module),
alloc->getType(),
false, /* not constant */
GlobalValue::ExternalLinkage,
NULL, /* no initializer */
alloc->getName().str().c_str());
// What we're going to do here is make believe this was a regular old external
// variable. That means we need to make the metadata valid.
NamedMDNode *named_metadata = m_module->getOrInsertNamedMetadata("clang.global.decl.ptrs");
llvm::Metadata *values[2];
values[0] = ConstantAsMetadata::get(persistent_global);
values[1] = ConstantAsMetadata::get(constant_int);
ArrayRef<llvm::Metadata *> value_ref(values, 2);
MDNode *persistent_global_md = MDNode::get(m_module->getContext(), value_ref);
named_metadata->addOperand(persistent_global_md);
// Now, since the variable is a pointer variable, we will drop in a load of that
// pointer variable.
LoadInst *persistent_load = new LoadInst (persistent_global, "", alloc);
if (log)
log->Printf("Replacing \"%s\" with \"%s\"",
PrintValue(alloc).c_str(),
PrintValue(persistent_load).c_str());
alloc->replaceAllUsesWith(persistent_load);
alloc->eraseFromParent();
return true;
}
bool
IRForTarget::RewritePersistentAllocs(llvm::BasicBlock &basic_block)
{
if (!m_resolve_vars)
return true;
lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
BasicBlock::iterator ii;
typedef SmallVector <Instruction*, 2> InstrList;
typedef InstrList::iterator InstrIterator;
InstrList pvar_allocs;
for (ii = basic_block.begin();
ii != basic_block.end();
++ii)
{
Instruction &inst = *ii;
if (AllocaInst *alloc = dyn_cast<AllocaInst>(&inst))
{
llvm::StringRef alloc_name = alloc->getName();
if (alloc_name.startswith("$") &&
!alloc_name.startswith("$__lldb"))
{
if (alloc_name.find_first_of("0123456789") == 1)
{
if (log)
log->Printf("Rejecting a numeric persistent variable.");
if (m_error_stream)
m_error_stream->Printf("Error [IRForTarget]: Names starting with $0, $1, ... are reserved for use as result names\n");
return false;
}
pvar_allocs.push_back(alloc);
}
}
}
InstrIterator iter;
for (iter = pvar_allocs.begin();
iter != pvar_allocs.end();
++iter)
{
if (!RewritePersistentAlloc(*iter))
{
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Couldn't rewrite the creation of a persistent variable\n");
if (log)
log->PutCString("Couldn't rewrite the creation of a persistent variable");
return false;
}
}
return true;
}
bool
IRForTarget::MaterializeInitializer (uint8_t *data, Constant *initializer)
{
if (!initializer)
return true;
lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
if (log && log->GetVerbose())
log->Printf(" MaterializeInitializer(%p, %s)", (void *)data, PrintValue(initializer).c_str());
Type *initializer_type = initializer->getType();
if (ConstantInt *int_initializer = dyn_cast<ConstantInt>(initializer))
{
size_t constant_size = m_target_data->getTypeStoreSize(initializer_type);
lldb_private::Scalar scalar = int_initializer->getValue().zextOrTrunc(llvm::NextPowerOf2(constant_size) * 8);
lldb_private::Error get_data_error;
if (!scalar.GetAsMemoryData(data, constant_size, lldb_private::endian::InlHostByteOrder(), get_data_error))
return false;
return true;
}
else if (ConstantDataArray *array_initializer = dyn_cast<ConstantDataArray>(initializer))
{
if (array_initializer->isString())
{
std::string array_initializer_string = array_initializer->getAsString();
memcpy (data, array_initializer_string.c_str(), m_target_data->getTypeStoreSize(initializer_type));
}
else
{
ArrayType *array_initializer_type = array_initializer->getType();
Type *array_element_type = array_initializer_type->getElementType();
size_t element_size = m_target_data->getTypeAllocSize(array_element_type);
for (unsigned i = 0; i < array_initializer->getNumOperands(); ++i)
{
Value *operand_value = array_initializer->getOperand(i);
Constant *operand_constant = dyn_cast<Constant>(operand_value);
if (!operand_constant)
return false;
if (!MaterializeInitializer(data + (i * element_size), operand_constant))
return false;
}
}
return true;
}
else if (ConstantStruct *struct_initializer = dyn_cast<ConstantStruct>(initializer))
{
StructType *struct_initializer_type = struct_initializer->getType();
const StructLayout *struct_layout = m_target_data->getStructLayout(struct_initializer_type);
for (unsigned i = 0;
i < struct_initializer->getNumOperands();
++i)
{
if (!MaterializeInitializer(data + struct_layout->getElementOffset(i), struct_initializer->getOperand(i)))
return false;
}
return true;
}
else if (isa<ConstantAggregateZero>(initializer))
{
memset(data, 0, m_target_data->getTypeStoreSize(initializer_type));
return true;
}
return false;
}
// This function does not report errors; its callers are responsible.
bool
IRForTarget::MaybeHandleVariable (Value *llvm_value_ptr)
{
lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
if (log)
log->Printf("MaybeHandleVariable (%s)", PrintValue(llvm_value_ptr).c_str());
if (ConstantExpr *constant_expr = dyn_cast<ConstantExpr>(llvm_value_ptr))
{
switch (constant_expr->getOpcode())
{
default:
break;
case Instruction::GetElementPtr:
case Instruction::BitCast:
Value *s = constant_expr->getOperand(0);
if (!MaybeHandleVariable(s))
return false;
}
}
else if (GlobalVariable *global_variable = dyn_cast<GlobalVariable>(llvm_value_ptr))
{
if (!GlobalValue::isExternalLinkage(global_variable->getLinkage()))
return true;
clang::NamedDecl *named_decl = DeclForGlobal(global_variable);
if (!named_decl)
{
if (IsObjCSelectorRef(llvm_value_ptr))
return true;
if (!global_variable->hasExternalLinkage())
return true;
if (log)
log->Printf("Found global variable \"%s\" without metadata", global_variable->getName().str().c_str());
return false;
}
std::string name (named_decl->getName().str());
clang::ValueDecl *value_decl = dyn_cast<clang::ValueDecl>(named_decl);
if (value_decl == NULL)
return false;
lldb_private::CompilerType compiler_type(&value_decl->getASTContext(), value_decl->getType());
const Type *value_type = NULL;
if (name[0] == '$')
{
// The $__lldb_expr_result name indicates the return value has allocated as
// a static variable. Per the comment at ASTResultSynthesizer::SynthesizeBodyResult,
// accesses to this static variable need to be redirected to the result of dereferencing
// a pointer that is passed in as one of the arguments.
//
// Consequently, when reporting the size of the type, we report a pointer type pointing
// to the type of $__lldb_expr_result, not the type itself.
//
// We also do this for any user-declared persistent variables.
compiler_type = compiler_type.GetPointerType();
value_type = PointerType::get(global_variable->getType(), 0);
}
else
{
value_type = global_variable->getType();
}
const uint64_t value_size = compiler_type.GetByteSize(nullptr);
lldb::offset_t value_alignment = (compiler_type.GetTypeBitAlign() + 7ull) / 8ull;
if (log)
{
log->Printf("Type of \"%s\" is [clang \"%s\", llvm \"%s\"] [size %" PRIu64 ", align %" PRIu64 "]",
name.c_str(), lldb_private::ClangUtil::GetQualType(compiler_type).getAsString().c_str(),
PrintType(value_type).c_str(), value_size, value_alignment);
}
if (named_decl && !m_decl_map->AddValueToStruct(named_decl,
lldb_private::ConstString (name.c_str()),
llvm_value_ptr,
value_size,
value_alignment))
{
if (!global_variable->hasExternalLinkage())
return true;
else
return true;
}
}
else if (dyn_cast<llvm::Function>(llvm_value_ptr))
{
if (log)
log->Printf("Function pointers aren't handled right now");
return false;
}
return true;
}
// This function does not report errors; its callers are responsible.
bool
IRForTarget::HandleSymbol (Value *symbol)
{
lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
lldb_private::ConstString name(symbol->getName().str().c_str());
lldb::addr_t symbol_addr = m_decl_map->GetSymbolAddress (name, lldb::eSymbolTypeAny);
if (symbol_addr == LLDB_INVALID_ADDRESS)
{
if (log)
log->Printf ("Symbol \"%s\" had no address", name.GetCString());
return false;
}
if (log)
log->Printf("Found \"%s\" at 0x%" PRIx64, name.GetCString(), symbol_addr);
Type *symbol_type = symbol->getType();
Constant *symbol_addr_int = ConstantInt::get(m_intptr_ty, symbol_addr, false);
Value *symbol_addr_ptr = ConstantExpr::getIntToPtr(symbol_addr_int, symbol_type);
if (log)
log->Printf("Replacing %s with %s", PrintValue(symbol).c_str(), PrintValue(symbol_addr_ptr).c_str());
symbol->replaceAllUsesWith(symbol_addr_ptr);
return true;
}
bool
IRForTarget::MaybeHandleCallArguments (CallInst *Old)
{
lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
if (log)
log->Printf("MaybeHandleCallArguments(%s)", PrintValue(Old).c_str());
for (unsigned op_index = 0, num_ops = Old->getNumArgOperands();
op_index < num_ops;
++op_index)
if (!MaybeHandleVariable(Old->getArgOperand(op_index))) // conservatively believe that this is a store
{
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Couldn't rewrite one of the arguments of a function call.\n");
return false;
}
return true;
}
bool
IRForTarget::HandleObjCClass(Value *classlist_reference)
{
lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
GlobalVariable *global_variable = dyn_cast<GlobalVariable>(classlist_reference);
if (!global_variable)
return false;
Constant *initializer = global_variable->getInitializer();
if (!initializer)
return false;
if (!initializer->hasName())
return false;
StringRef name(initializer->getName());
lldb_private::ConstString name_cstr(name.str().c_str());
lldb::addr_t class_ptr = m_decl_map->GetSymbolAddress(name_cstr, lldb::eSymbolTypeObjCClass);
if (log)
log->Printf("Found reference to Objective-C class %s (0x%llx)", name_cstr.AsCString(), (unsigned long long)class_ptr);
if (class_ptr == LLDB_INVALID_ADDRESS)
return false;
if (global_variable->use_empty())
return false;
SmallVector<LoadInst *, 2> load_instructions;
for (llvm::User *u : global_variable->users())
{
if (LoadInst *load_instruction = dyn_cast<LoadInst>(u))
load_instructions.push_back(load_instruction);
}
if (load_instructions.empty())
return false;
Constant *class_addr = ConstantInt::get(m_intptr_ty, (uint64_t)class_ptr);
for (LoadInst *load_instruction : load_instructions)
{
Constant *class_bitcast = ConstantExpr::getIntToPtr(class_addr, load_instruction->getType());
load_instruction->replaceAllUsesWith(class_bitcast);
load_instruction->eraseFromParent();
}
return true;
}
bool
IRForTarget::RemoveCXAAtExit (BasicBlock &basic_block)
{
BasicBlock::iterator ii;
std::vector<CallInst *> calls_to_remove;
for (ii = basic_block.begin();
ii != basic_block.end();
++ii)
{
Instruction &inst = *ii;
CallInst *call = dyn_cast<CallInst>(&inst);
// MaybeHandleCallArguments handles error reporting; we are silent here
if (!call)
continue;
bool remove = false;
llvm::Function *func = call->getCalledFunction();
if (func && func->getName() == "__cxa_atexit")
remove = true;
llvm::Value *val = call->getCalledValue();
if (val && val->getName() == "__cxa_atexit")
remove = true;
if (remove)
calls_to_remove.push_back(call);
}
for (std::vector<CallInst *>::iterator ci = calls_to_remove.begin(), ce = calls_to_remove.end();
ci != ce;
++ci)
{
(*ci)->eraseFromParent();
}
return true;
}
bool
IRForTarget::ResolveCalls(BasicBlock &basic_block)
{
/////////////////////////////////////////////////////////////////////////
// Prepare the current basic block for execution in the remote process
//
BasicBlock::iterator ii;
for (ii = basic_block.begin();
ii != basic_block.end();
++ii)
{
Instruction &inst = *ii;
CallInst *call = dyn_cast<CallInst>(&inst);
// MaybeHandleCallArguments handles error reporting; we are silent here
if (call && !MaybeHandleCallArguments(call))
return false;
}
return true;
}
bool
IRForTarget::ResolveExternals (Function &llvm_function)
{
lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
for (GlobalVariable &global_var : m_module->globals())
{
std::string global_name = global_var.getName().str();
if (log)
log->Printf("Examining %s, DeclForGlobalValue returns %p",
global_name.c_str(),
static_cast<void*>(DeclForGlobal(&global_var)));
if (global_name.find("OBJC_IVAR") == 0)
{
if (!HandleSymbol(&global_var))
{
if (m_error_stream)
m_error_stream->Printf("Error [IRForTarget]: Couldn't find Objective-C indirect ivar symbol %s\n", global_name.c_str());
return false;
}
}
else if (global_name.find("OBJC_CLASSLIST_REFERENCES_$") != global_name.npos)
{
if (!HandleObjCClass(&global_var))
{
if (m_error_stream)
m_error_stream->Printf("Error [IRForTarget]: Couldn't resolve the class for an Objective-C static method call\n");
return false;
}
}
else if (global_name.find("OBJC_CLASSLIST_SUP_REFS_$") != global_name.npos)
{
if (!HandleObjCClass(&global_var))
{
if (m_error_stream)
m_error_stream->Printf("Error [IRForTarget]: Couldn't resolve the class for an Objective-C static method call\n");
return false;
}
}
else if (DeclForGlobal(&global_var))
{
if (!MaybeHandleVariable (&global_var))
{
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Couldn't rewrite external variable %s\n", global_name.c_str());
return false;
}
}
}
return true;
}
static bool isGuardVariableRef(Value *V)
{
Constant *Old = NULL;
if (!(Old = dyn_cast<Constant>(V)))
return false;
ConstantExpr *CE = NULL;
if ((CE = dyn_cast<ConstantExpr>(V)))
{
if (CE->getOpcode() != Instruction::BitCast)
return false;
Old = CE->getOperand(0);
}
GlobalVariable *GV = dyn_cast<GlobalVariable>(Old);
if (!GV || !GV->hasName() ||
(!GV->getName().startswith("_ZGV") && // Itanium ABI guard variable
!GV->getName().endswith("@4IA"))) // Microsoft ABI guard variable
{
return false;
}
return true;
}
void
IRForTarget::TurnGuardLoadIntoZero(llvm::Instruction* guard_load)
{
Constant *zero(Constant::getNullValue(guard_load->getType()));
guard_load->replaceAllUsesWith(zero);
guard_load->eraseFromParent();
}
static void ExciseGuardStore(Instruction* guard_store)
{
guard_store->eraseFromParent();
}
bool
IRForTarget::RemoveGuards(BasicBlock &basic_block)
{
///////////////////////////////////////////////////////
// Eliminate any reference to guard variables found.
//
BasicBlock::iterator ii;
typedef SmallVector <Instruction*, 2> InstrList;
typedef InstrList::iterator InstrIterator;
InstrList guard_loads;
InstrList guard_stores;
for (ii = basic_block.begin();
ii != basic_block.end();
++ii)
{
Instruction &inst = *ii;
if (LoadInst *load = dyn_cast<LoadInst>(&inst))
if (isGuardVariableRef(load->getPointerOperand()))
guard_loads.push_back(&inst);
if (StoreInst *store = dyn_cast<StoreInst>(&inst))
if (isGuardVariableRef(store->getPointerOperand()))
guard_stores.push_back(&inst);
}
InstrIterator iter;
for (iter = guard_loads.begin();
iter != guard_loads.end();
++iter)
TurnGuardLoadIntoZero(*iter);
for (iter = guard_stores.begin();
iter != guard_stores.end();
++iter)
ExciseGuardStore(*iter);
return true;
}
// This function does not report errors; its callers are responsible.
bool
IRForTarget::UnfoldConstant(Constant *old_constant,
FunctionValueCache &value_maker,
FunctionValueCache &entry_instruction_finder)
{
lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
SmallVector<User*, 16> users;
// We do this because the use list might change, invalidating our iterator.
// Much better to keep a work list ourselves.
for (llvm::User *u : old_constant->users())
users.push_back(u);
for (size_t i = 0;
i < users.size();
++i)
{
User *user = users[i];
if (Constant *constant = dyn_cast<Constant>(user))
{
// synthesize a new non-constant equivalent of the constant
if (ConstantExpr *constant_expr = dyn_cast<ConstantExpr>(constant))
{
switch (constant_expr->getOpcode())
{
default:
if (log)
log->Printf("Unhandled constant expression type: \"%s\"", PrintValue(constant_expr).c_str());
return false;
case Instruction::BitCast:
{
FunctionValueCache bit_cast_maker ([&value_maker, &entry_instruction_finder, old_constant, constant_expr] (llvm::Function *function)->llvm::Value* {
// UnaryExpr
// OperandList[0] is value
if (constant_expr->getOperand(0) != old_constant)
return constant_expr;
return new BitCastInst(value_maker.GetValue(function),
constant_expr->getType(),
"",
llvm::cast<Instruction>(entry_instruction_finder.GetValue(function)));
});
if (!UnfoldConstant(constant_expr, bit_cast_maker, entry_instruction_finder))
return false;
}
break;
case Instruction::GetElementPtr:
{
// GetElementPtrConstantExpr
// OperandList[0] is base
// OperandList[1]... are indices
FunctionValueCache get_element_pointer_maker ([&value_maker, &entry_instruction_finder, old_constant, constant_expr] (llvm::Function *function)->llvm::Value* {
Value *ptr = constant_expr->getOperand(0);
if (ptr == old_constant)
ptr = value_maker.GetValue(function);
std::vector<Value*> index_vector;
unsigned operand_index;
unsigned num_operands = constant_expr->getNumOperands();
for (operand_index = 1;
operand_index < num_operands;
++operand_index)
{
Value *operand = constant_expr->getOperand(operand_index);
if (operand == old_constant)
operand = value_maker.GetValue(function);
index_vector.push_back(operand);
}
ArrayRef <Value*> indices(index_vector);
return GetElementPtrInst::Create(nullptr, ptr, indices, "", llvm::cast<Instruction>(entry_instruction_finder.GetValue(function)));
});
if (!UnfoldConstant(constant_expr, get_element_pointer_maker, entry_instruction_finder))
return false;
}
break;
}
}
else
{
if (log)
log->Printf("Unhandled constant type: \"%s\"", PrintValue(constant).c_str());
return false;
}
}
else
{
if (Instruction *inst = llvm::dyn_cast<Instruction>(user))
{
inst->replaceUsesOfWith(old_constant, value_maker.GetValue(inst->getParent()->getParent()));
}
else
{
if (log)
log->Printf("Unhandled non-constant type: \"%s\"", PrintValue(user).c_str());
return false;
}
}
}
if (!isa<GlobalValue>(old_constant))
{
old_constant->destroyConstant();
}
return true;
}
bool
IRForTarget::ReplaceVariables (Function &llvm_function)
{
if (!m_resolve_vars)
return true;
lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
m_decl_map->DoStructLayout();
if (log)
log->Printf("Element arrangement:");
uint32_t num_elements;
uint32_t element_index;
size_t size;
lldb::offset_t alignment;
if (!m_decl_map->GetStructInfo (num_elements, size, alignment))
return false;
Function::arg_iterator iter(llvm_function.getArgumentList().begin());
if (iter == llvm_function.getArgumentList().end())
{
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Wrapper takes no arguments (should take at least a struct pointer)");
return false;
}
Argument *argument = &*iter;
if (argument->getName().equals("this"))
{
++iter;
if (iter == llvm_function.getArgumentList().end())
{
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Wrapper takes only 'this' argument (should take a struct pointer too)");
return false;
}
argument = &*iter;
}
else if (argument->getName().equals("self"))
{
++iter;
if (iter == llvm_function.getArgumentList().end())
{
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Wrapper takes only 'self' argument (should take '_cmd' and a struct pointer too)");
return false;
}
if (!iter->getName().equals("_cmd"))
{
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Wrapper takes '%s' after 'self' argument (should take '_cmd')", iter->getName().str().c_str());
return false;
}
++iter;
if (iter == llvm_function.getArgumentList().end())
{
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Wrapper takes only 'self' and '_cmd' arguments (should take a struct pointer too)");
return false;
}
argument = &*iter;
}
if (!argument->getName().equals("$__lldb_arg"))
{
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Wrapper takes an argument named '%s' instead of the struct pointer", argument->getName().str().c_str());
return false;
}
if (log)
log->Printf("Arg: \"%s\"", PrintValue(argument).c_str());
BasicBlock &entry_block(llvm_function.getEntryBlock());
Instruction *FirstEntryInstruction(entry_block.getFirstNonPHIOrDbg());
if (!FirstEntryInstruction)
{
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Couldn't find the first instruction in the wrapper for use in rewriting");
return false;
}
LLVMContext &context(m_module->getContext());
IntegerType *offset_type(Type::getInt32Ty(context));
if (!offset_type)
{
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Couldn't produce an offset type");
return false;
}
for (element_index = 0; element_index < num_elements; ++element_index)
{
const clang::NamedDecl *decl = NULL;
Value *value = NULL;
lldb::offset_t offset;
lldb_private::ConstString name;
if (!m_decl_map->GetStructElement (decl, value, offset, name, element_index))
{
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Structure information is incomplete");
return false;
}
if (log)
log->Printf(" \"%s\" (\"%s\") placed at %" PRIu64,
name.GetCString(),
decl->getNameAsString().c_str(),
offset);
if (value)
{
if (log)
log->Printf(" Replacing [%s]", PrintValue(value).c_str());
FunctionValueCache body_result_maker ([this, name, offset_type, offset, argument, value] (llvm::Function *function)->llvm::Value * {
// Per the comment at ASTResultSynthesizer::SynthesizeBodyResult, in cases where the result
// variable is an rvalue, we have to synthesize a dereference of the appropriate structure
// entry in order to produce the static variable that the AST thinks it is accessing.
llvm::Instruction *entry_instruction = llvm::cast<Instruction>(m_entry_instruction_finder.GetValue(function));
ConstantInt *offset_int(ConstantInt::get(offset_type, offset, true));
GetElementPtrInst *get_element_ptr = GetElementPtrInst::Create(nullptr,
argument,
offset_int,
"",
entry_instruction);
if (name == m_result_name && !m_result_is_pointer)
{
BitCastInst *bit_cast = new BitCastInst(get_element_ptr,
value->getType()->getPointerTo(),
"",
entry_instruction);
LoadInst *load = new LoadInst(bit_cast, "", entry_instruction);
return load;
}
else
{
BitCastInst *bit_cast = new BitCastInst(get_element_ptr, value->getType(), "", entry_instruction);
return bit_cast;
}
});
if (Constant *constant = dyn_cast<Constant>(value))
{
UnfoldConstant(constant, body_result_maker, m_entry_instruction_finder);
}
else if (Instruction *instruction = dyn_cast<Instruction>(value))
{
value->replaceAllUsesWith(body_result_maker.GetValue(instruction->getParent()->getParent()));
}
else
{
if (log)
log->Printf("Unhandled non-constant type: \"%s\"", PrintValue(value).c_str());
return false;
}
if (GlobalVariable *var = dyn_cast<GlobalVariable>(value))
var->eraseFromParent();
}
}
if (log)
log->Printf("Total structure [align %" PRId64 ", size %" PRIu64 "]", (int64_t)alignment, (uint64_t)size);
return true;
}
llvm::Constant *
IRForTarget::BuildRelocation(llvm::Type *type, uint64_t offset)
{
llvm::Constant *offset_int = ConstantInt::get(m_intptr_ty, offset);
llvm::Constant *offset_array[1];
offset_array[0] = offset_int;
llvm::ArrayRef<llvm::Constant *> offsets(offset_array, 1);
llvm::Type *char_type = llvm::Type::getInt8Ty(m_module->getContext());
llvm::Type *char_pointer_type = char_type->getPointerTo();
llvm::Constant *reloc_placeholder_bitcast = ConstantExpr::getBitCast(m_reloc_placeholder, char_pointer_type);
llvm::Constant *reloc_getelementptr = ConstantExpr::getGetElementPtr(char_type, reloc_placeholder_bitcast, offsets);
llvm::Constant *reloc_bitcast = ConstantExpr::getBitCast(reloc_getelementptr, type);
return reloc_bitcast;
}
bool
IRForTarget::runOnModule (Module &llvm_module)
{
lldb_private::Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
m_module = &llvm_module;
m_target_data.reset(new DataLayout(m_module));
m_intptr_ty = llvm::Type::getIntNTy(m_module->getContext(), m_target_data->getPointerSizeInBits());
if (log)
{
std::string s;
raw_string_ostream oss(s);
m_module->print(oss, NULL);
oss.flush();
log->Printf("Module as passed in to IRForTarget: \n\"%s\"", s.c_str());
}
Function *const main_function = m_func_name.IsEmpty() ? nullptr : m_module->getFunction(m_func_name.GetStringRef());
if (!m_func_name.IsEmpty() && !main_function)
{
if (log)
log->Printf("Couldn't find \"%s()\" in the module", m_func_name.AsCString());
if (m_error_stream)
m_error_stream->Printf("Internal error [IRForTarget]: Couldn't find wrapper '%s' in the module",
m_func_name.AsCString());
return false;
}
if (main_function)
{
if (!FixFunctionLinkage(*main_function))
{
if (log)
log->Printf("Couldn't fix the linkage for the function");
return false;
}
}
llvm::Type *int8_ty = Type::getInt8Ty(m_module->getContext());
m_reloc_placeholder = new llvm::GlobalVariable((*m_module),
int8_ty,
false /* IsConstant */,
GlobalVariable::InternalLinkage,
Constant::getNullValue(int8_ty),
"reloc_placeholder",
NULL /* InsertBefore */,
GlobalVariable::NotThreadLocal /* ThreadLocal */,
0 /* AddressSpace */);
////////////////////////////////////////////////////////////
// Replace $__lldb_expr_result with a persistent variable
//
if (main_function)
{
if (!CreateResultVariable(*main_function))
{
if (log)
log->Printf("CreateResultVariable() failed");
// CreateResultVariable() reports its own errors, so we don't do so here
return false;
}
}
if (log && log->GetVerbose())
{
std::string s;
raw_string_ostream oss(s);
m_module->print(oss, NULL);
oss.flush();
log->Printf("Module after creating the result variable: \n\"%s\"", s.c_str());
}
for (Module::iterator fi = m_module->begin(), fe = m_module->end();
fi != fe;
++fi)
{
llvm::Function *function = &*fi;
if (function->begin() == function->end())
continue;
Function::iterator bbi;
for (bbi = function->begin();
bbi != function->end();
++bbi)
{
if (!RemoveGuards(*bbi))
{
if (log)
log->Printf("RemoveGuards() failed");
// RemoveGuards() reports its own errors, so we don't do so here
return false;
}
if (!RewritePersistentAllocs(*bbi))
{
if (log)
log->Printf("RewritePersistentAllocs() failed");
// RewritePersistentAllocs() reports its own errors, so we don't do so here
return false;
}
if (!RemoveCXAAtExit(*bbi))
{
if (log)
log->Printf("RemoveCXAAtExit() failed");
// RemoveCXAAtExit() reports its own errors, so we don't do so here
return false;
}
}
}
///////////////////////////////////////////////////////////////////////////////
// Fix all Objective-C constant strings to use NSStringWithCString:encoding:
//
if (!RewriteObjCConstStrings())
{
if (log)
log->Printf("RewriteObjCConstStrings() failed");
// RewriteObjCConstStrings() reports its own errors, so we don't do so here
return false;
}
for (Module::iterator fi = m_module->begin(), fe = m_module->end();
fi != fe;
++fi)
{
llvm::Function *function = &*fi;
for (llvm::Function::iterator bbi = function->begin(), bbe = function->end();
bbi != bbe;
++bbi)
{
if (!RewriteObjCSelectors(*bbi))
{
if (log)
log->Printf("RewriteObjCSelectors() failed");
// RewriteObjCSelectors() reports its own errors, so we don't do so here
return false;
}
}
}
for (Module::iterator fi = m_module->begin(), fe = m_module->end();
fi != fe;
++fi)
{
llvm::Function *function = &*fi;
for (llvm::Function::iterator bbi = function->begin(), bbe = function->end();
bbi != bbe;
++bbi)
{
if (!ResolveCalls(*bbi))
{
if (log)
log->Printf("ResolveCalls() failed");
// ResolveCalls() reports its own errors, so we don't do so here
return false;
}
}
}
////////////////////////////////////////////////////////////////////////
// Run function-level passes that only make sense on the main function
//
if (main_function)
{
if (!ResolveExternals(*main_function))
{
if (log)
log->Printf("ResolveExternals() failed");
// ResolveExternals() reports its own errors, so we don't do so here
return false;
}
if (!ReplaceVariables(*main_function))
{
if (log)
log->Printf("ReplaceVariables() failed");
// ReplaceVariables() reports its own errors, so we don't do so here
return false;
}
}
if (log && log->GetVerbose())
{
std::string s;
raw_string_ostream oss(s);
m_module->print(oss, NULL);
oss.flush();
log->Printf("Module after preparing for execution: \n\"%s\"", s.c_str());
}
return true;
}
void
IRForTarget::assignPassManager (PMStack &pass_mgr_stack, PassManagerType pass_mgr_type)
{
}
PassManagerType
IRForTarget::getPotentialPassManagerType() const
{
return PMT_ModulePassManager;
}
Reference in New Issue View Git Blame Copy Permalink