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llvm-project/lldb/source/Expression/ClangFunction.cpp
Sean Callanan 1582ee6840 This commit changes the way LLDB executes user 
expressions.  

Previously, ClangUserExpression assumed that if
there was a constant result for an expression 
then it could be determined during parsing.  In
particular, the IRInterpreter ran while parser
state (in particular, ClangExpressionDeclMap) 
was present.  This approach is flawed, because
the IRInterpreter actually is capable of using
external variables, and hence the result might
be different each run.  Until now, we papered
over this flaw by re-parsing the expression each
time we ran it.

I have rewritten the IRInterpreter to be 
completely independent of the ClangExpressionDeclMap.
Instead of special-casing external variable lookup,
which ties the IRInterpreter closely to LLDB,
we now interpret the exact same IR that the JIT
would see.  This IR assumes that materialization
has occurred; hence the recent implementation of the
Materializer, which does not require parser state
(in the form of ClangExpressionDeclMap) to be 
present.

Materialization, interpretation, and dematerialization
are now all independent of parsing.  This means that
in theory we can parse expressions once and run them
many times.  I have three outstanding tasks before
shutting this down:

    - First, I will ensure that all of this works with
      core files.  Core files have a Process but do not
      allow allocating memory, which currently confuses
      materialization.

    - Second, I will make expression breakpoint 
      conditions remember their ClangUserExpression and
      re-use it.

    - Third, I will tear out all the redundant code
      (for example, materialization logic in
      ClangExpressionDeclMap) that is no longer used.

While implementing this fix, I also found a bug in
IRForTarget's handling of floating-point constants.  
This should be fixed.

llvm-svn: 179801
2013-04-18 22:06:33 +00:00

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//===-- ClangFunction.cpp ---------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// C Includes
// C++ Includes
// Other libraries and framework includes
#include "clang/AST/ASTContext.h"
#include "clang/AST/RecordLayout.h"
#include "clang/CodeGen/CodeGenAction.h"
#include "clang/CodeGen/ModuleBuilder.h"
#include "clang/Frontend/CompilerInstance.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Triple.h"
#include "llvm/ExecutionEngine/ExecutionEngine.h"
#include "llvm/IR/Module.h"
// Project includes
#include "lldb/Expression/ASTStructExtractor.h"
#include "lldb/Expression/ClangExpressionParser.h"
#include "lldb/Expression/ClangFunction.h"
#include "lldb/Expression/IRExecutionUnit.h"
#include "lldb/Symbol/Type.h"
#include "lldb/Core/DataExtractor.h"
#include "lldb/Core/State.h"
#include "lldb/Core/ValueObject.h"
#include "lldb/Core/ValueObjectList.h"
#include "lldb/Interpreter/CommandReturnObject.h"
#include "lldb/Symbol/ClangASTContext.h"
#include "lldb/Symbol/Function.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "lldb/Target/ThreadPlan.h"
#include "lldb/Target/ThreadPlanCallFunction.h"
#include "lldb/Core/Log.h"
using namespace lldb_private;
//----------------------------------------------------------------------
// ClangFunction constructor
//----------------------------------------------------------------------
ClangFunction::ClangFunction
(
ExecutionContextScope &exe_scope,
ClangASTContext *ast_context,
void *return_qualtype,
const Address& functionAddress,
const ValueList &arg_value_list
) :
m_function_ptr (NULL),
m_function_addr (functionAddress),
m_function_return_qual_type(return_qualtype),
m_clang_ast_context (ast_context),
m_wrapper_function_name ("__lldb_caller_function"),
m_wrapper_struct_name ("__lldb_caller_struct"),
m_wrapper_args_addrs (),
m_arg_values (arg_value_list),
m_compiled (false),
m_JITted (false)
{
m_jit_process_wp = lldb::ProcessWP(exe_scope.CalculateProcess());
// Can't make a ClangFunction without a process.
assert (m_jit_process_wp.lock());
}
ClangFunction::ClangFunction
(
ExecutionContextScope &exe_scope,
Function &function,
ClangASTContext *ast_context,
const ValueList &arg_value_list
) :
m_function_ptr (&function),
m_function_addr (),
m_function_return_qual_type (),
m_clang_ast_context (ast_context),
m_wrapper_function_name ("__lldb_function_caller"),
m_wrapper_struct_name ("__lldb_caller_struct"),
m_wrapper_args_addrs (),
m_arg_values (arg_value_list),
m_compiled (false),
m_JITted (false)
{
m_jit_process_wp = lldb::ProcessWP(exe_scope.CalculateProcess());
// Can't make a ClangFunction without a process.
assert (m_jit_process_wp.lock());
m_function_addr = m_function_ptr->GetAddressRange().GetBaseAddress();
m_function_return_qual_type = m_function_ptr->GetReturnClangType();
}
//----------------------------------------------------------------------
// Destructor
//----------------------------------------------------------------------
ClangFunction::~ClangFunction()
{
}
unsigned
ClangFunction::CompileFunction (Stream &errors)
{
if (m_compiled)
return 0;
// FIXME: How does clang tell us there's no return value? We need to handle that case.
unsigned num_errors = 0;
std::string return_type_str (ClangASTType::GetTypeNameForOpaqueQualType (m_clang_ast_context->getASTContext(),
m_function_return_qual_type));
// Cons up the function we're going to wrap our call in, then compile it...
// We declare the function "extern "C"" because the compiler might be in C++
// mode which would mangle the name and then we couldn't find it again...
m_wrapper_function_text.clear();
m_wrapper_function_text.append ("extern \"C\" void ");
m_wrapper_function_text.append (m_wrapper_function_name);
m_wrapper_function_text.append (" (void *input)\n{\n struct ");
m_wrapper_function_text.append (m_wrapper_struct_name);
m_wrapper_function_text.append (" \n {\n");
m_wrapper_function_text.append (" ");
m_wrapper_function_text.append (return_type_str);
m_wrapper_function_text.append (" (*fn_ptr) (");
// Get the number of arguments. If we have a function type and it is prototyped,
// trust that, otherwise use the values we were given.
// FIXME: This will need to be extended to handle Variadic functions. We'll need
// to pull the defined arguments out of the function, then add the types from the
// arguments list for the variable arguments.
size_t num_args = UINT32_MAX;
bool trust_function = false;
// GetArgumentCount returns -1 for an unprototyped function.
if (m_function_ptr)
{
int num_func_args = m_function_ptr->GetArgumentCount();
if (num_func_args >= 0)
trust_function = true;
else
num_args = num_func_args;
}
if (num_args == UINT32_MAX)
num_args = m_arg_values.GetSize();
std::string args_buffer; // This one stores the definition of all the args in "struct caller".
std::string args_list_buffer; // This one stores the argument list called from the structure.
for (size_t i = 0; i < num_args; i++)
{
std::string type_name;
if (trust_function)
{
lldb::clang_type_t arg_clang_type = m_function_ptr->GetArgumentTypeAtIndex(i);
type_name = ClangASTType::GetTypeNameForOpaqueQualType (m_clang_ast_context->getASTContext(),
arg_clang_type);
}
else
{
Value *arg_value = m_arg_values.GetValueAtIndex(i);
lldb::clang_type_t clang_qual_type = arg_value->GetClangType ();
if (clang_qual_type != NULL)
{
type_name = ClangASTType::GetTypeNameForOpaqueQualType (m_clang_ast_context->getASTContext(),
clang_qual_type);
}
else
{
errors.Printf("Could not determine type of input value %lu.", i);
return 1;
}
}
m_wrapper_function_text.append (type_name);
if (i < num_args - 1)
m_wrapper_function_text.append (", ");
char arg_buf[32];
args_buffer.append (" ");
args_buffer.append (type_name);
snprintf(arg_buf, 31, "arg_%" PRIu64, (uint64_t)i);
args_buffer.push_back (' ');
args_buffer.append (arg_buf);
args_buffer.append (";\n");
args_list_buffer.append ("__lldb_fn_data->");
args_list_buffer.append (arg_buf);
if (i < num_args - 1)
args_list_buffer.append (", ");
}
m_wrapper_function_text.append (");\n"); // Close off the function calling prototype.
m_wrapper_function_text.append (args_buffer);
m_wrapper_function_text.append (" ");
m_wrapper_function_text.append (return_type_str);
m_wrapper_function_text.append (" return_value;");
m_wrapper_function_text.append ("\n };\n struct ");
m_wrapper_function_text.append (m_wrapper_struct_name);
m_wrapper_function_text.append ("* __lldb_fn_data = (struct ");
m_wrapper_function_text.append (m_wrapper_struct_name);
m_wrapper_function_text.append (" *) input;\n");
m_wrapper_function_text.append (" __lldb_fn_data->return_value = __lldb_fn_data->fn_ptr (");
m_wrapper_function_text.append (args_list_buffer);
m_wrapper_function_text.append (");\n}\n");
Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
if (log)
log->Printf ("Expression: \n\n%s\n\n", m_wrapper_function_text.c_str());
// Okay, now compile this expression
lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
if (jit_process_sp)
{
m_parser.reset(new ClangExpressionParser(jit_process_sp.get(), *this));
num_errors = m_parser->Parse (errors);
}
else
{
errors.Printf("no process - unable to inject function");
num_errors = 1;
}
m_compiled = (num_errors == 0);
if (!m_compiled)
return num_errors;
return num_errors;
}
bool
ClangFunction::WriteFunctionWrapper (ExecutionContext &exe_ctx, Stream &errors)
{
Process *process = exe_ctx.GetProcessPtr();
if (!process)
return false;
lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
if (process != jit_process_sp.get())
return false;
if (!m_compiled)
return false;
if (m_JITted)
return true;
bool can_interpret = false; // should stay that way
Error jit_error (m_parser->PrepareForExecution (m_jit_start_addr,
m_jit_end_addr,
m_execution_unit_ap,
exe_ctx,
can_interpret,
eExecutionPolicyAlways));
if (!jit_error.Success())
return false;
if (process && m_jit_start_addr)
m_jit_process_wp = lldb::ProcessWP(process->shared_from_this());
m_JITted = true;
return true;
}
bool
ClangFunction::WriteFunctionArguments (ExecutionContext &exe_ctx, lldb::addr_t &args_addr_ref, Stream &errors)
{
return WriteFunctionArguments(exe_ctx, args_addr_ref, m_function_addr, m_arg_values, errors);
}
// FIXME: Assure that the ValueList we were passed in is consistent with the one that defined this function.
bool
ClangFunction::WriteFunctionArguments (ExecutionContext &exe_ctx,
lldb::addr_t &args_addr_ref,
Address function_address,
ValueList &arg_values,
Stream &errors)
{
// All the information to reconstruct the struct is provided by the
// StructExtractor.
if (!m_struct_valid)
{
errors.Printf("Argument information was not correctly parsed, so the function cannot be called.");
return false;
}
Error error;
using namespace clang;
ExecutionResults return_value = eExecutionSetupError;
Process *process = exe_ctx.GetProcessPtr();
if (process == NULL)
return return_value;
lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
if (process != jit_process_sp.get())
return false;
if (args_addr_ref == LLDB_INVALID_ADDRESS)
{
args_addr_ref = process->AllocateMemory(m_struct_size, lldb::ePermissionsReadable|lldb::ePermissionsWritable, error);
if (args_addr_ref == LLDB_INVALID_ADDRESS)
return false;
m_wrapper_args_addrs.push_back (args_addr_ref);
}
else
{
// Make sure this is an address that we've already handed out.
if (find (m_wrapper_args_addrs.begin(), m_wrapper_args_addrs.end(), args_addr_ref) == m_wrapper_args_addrs.end())
{
return false;
}
}
// TODO: verify fun_addr needs to be a callable address
Scalar fun_addr (function_address.GetCallableLoadAddress(exe_ctx.GetTargetPtr()));
uint64_t first_offset = m_member_offsets[0];
process->WriteScalarToMemory(args_addr_ref + first_offset, fun_addr, process->GetAddressByteSize(), error);
// FIXME: We will need to extend this for Variadic functions.
Error value_error;
size_t num_args = arg_values.GetSize();
if (num_args != m_arg_values.GetSize())
{
errors.Printf ("Wrong number of arguments - was: %lu should be: %lu", num_args, m_arg_values.GetSize());
return false;
}
for (size_t i = 0; i < num_args; i++)
{
// FIXME: We should sanity check sizes.
uint64_t offset = m_member_offsets[i+1]; // Clang sizes are in bytes.
Value *arg_value = arg_values.GetValueAtIndex(i);
// FIXME: For now just do scalars:
// Special case: if it's a pointer, don't do anything (the ABI supports passing cstrings)
if (arg_value->GetValueType() == Value::eValueTypeHostAddress &&
arg_value->GetContextType() == Value::eContextTypeClangType &&
ClangASTContext::IsPointerType(arg_value->GetClangType()))
continue;
const Scalar &arg_scalar = arg_value->ResolveValue(&exe_ctx, m_clang_ast_context->getASTContext());
if (!process->WriteScalarToMemory(args_addr_ref + offset, arg_scalar, arg_scalar.GetByteSize(), error))
return false;
}
return true;
}
bool
ClangFunction::InsertFunction (ExecutionContext &exe_ctx, lldb::addr_t &args_addr_ref, Stream &errors)
{
using namespace clang;
if (CompileFunction(errors) != 0)
return false;
if (!WriteFunctionWrapper(exe_ctx, errors))
return false;
if (!WriteFunctionArguments(exe_ctx, args_addr_ref, errors))
return false;
Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
if (log)
log->Printf ("Call Address: 0x%" PRIx64 " Struct Address: 0x%" PRIx64 ".\n", m_jit_start_addr, args_addr_ref);
return true;
}
ThreadPlan *
ClangFunction::GetThreadPlanToCallFunction (ExecutionContext &exe_ctx,
lldb::addr_t func_addr,
lldb::addr_t &args_addr,
Stream &errors,
bool stop_others,
bool unwind_on_error,
bool ignore_breakpoints,
lldb::addr_t *this_arg,
lldb::addr_t *cmd_arg)
{
Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_EXPRESSIONS | LIBLLDB_LOG_STEP));
if (log)
log->Printf("-- [ClangFunction::GetThreadPlanToCallFunction] Creating thread plan to call function --");
// FIXME: Use the errors Stream for better error reporting.
Thread *thread = exe_ctx.GetThreadPtr();
if (thread == NULL)
{
errors.Printf("Can't call a function without a valid thread.");
return NULL;
}
// Okay, now run the function:
Address wrapper_address (func_addr);
ThreadPlan *new_plan = new ThreadPlanCallFunction (*thread,
wrapper_address,
ClangASTType(),
args_addr,
stop_others,
unwind_on_error,
ignore_breakpoints,
this_arg,
cmd_arg);
new_plan->SetIsMasterPlan(true);
new_plan->SetOkayToDiscard (false);
return new_plan;
}
bool
ClangFunction::FetchFunctionResults (ExecutionContext &exe_ctx, lldb::addr_t args_addr, Value &ret_value)
{
// Read the return value - it is the last field in the struct:
// FIXME: How does clang tell us there's no return value? We need to handle that case.
// FIXME: Create our ThreadPlanCallFunction with the return ClangASTType, and then use GetReturnValueObject
// to fetch the value. That way we can fetch any values we need.
Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_EXPRESSIONS | LIBLLDB_LOG_STEP));
if (log)
log->Printf("-- [ClangFunction::FetchFunctionResults] Fetching function results --");
Process *process = exe_ctx.GetProcessPtr();
if (process == NULL)
return false;
lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
if (process != jit_process_sp.get())
return false;
Error error;
ret_value.GetScalar() = process->ReadUnsignedIntegerFromMemory (args_addr + m_return_offset, m_return_size, 0, error);
if (error.Fail())
return false;
ret_value.SetContext (Value::eContextTypeClangType, m_function_return_qual_type);
ret_value.SetValueType(Value::eValueTypeScalar);
return true;
}
void
ClangFunction::DeallocateFunctionResults (ExecutionContext &exe_ctx, lldb::addr_t args_addr)
{
std::list<lldb::addr_t>::iterator pos;
pos = std::find(m_wrapper_args_addrs.begin(), m_wrapper_args_addrs.end(), args_addr);
if (pos != m_wrapper_args_addrs.end())
m_wrapper_args_addrs.erase(pos);
exe_ctx.GetProcessRef().DeallocateMemory(args_addr);
}
ExecutionResults
ClangFunction::ExecuteFunction(ExecutionContext &exe_ctx, Stream &errors, Value &results)
{
return ExecuteFunction (exe_ctx, errors, 1000, true, results);
}
ExecutionResults
ClangFunction::ExecuteFunction(ExecutionContext &exe_ctx, Stream &errors, bool stop_others, Value &results)
{
const bool try_all_threads = false;
const bool unwind_on_error = true;
const bool ignore_breakpoints = true;
return ExecuteFunction (exe_ctx, NULL, errors, stop_others, 0UL, try_all_threads,
unwind_on_error, ignore_breakpoints, results);
}
ExecutionResults
ClangFunction::ExecuteFunction(
ExecutionContext &exe_ctx,
Stream &errors,
uint32_t timeout_usec,
bool try_all_threads,
Value &results)
{
const bool stop_others = true;
const bool unwind_on_error = true;
const bool ignore_breakpoints = true;
return ExecuteFunction (exe_ctx, NULL, errors, stop_others, timeout_usec,
try_all_threads, unwind_on_error, ignore_breakpoints, results);
}
// This is the static function
ExecutionResults
ClangFunction::ExecuteFunction (
ExecutionContext &exe_ctx,
lldb::addr_t function_address,
lldb::addr_t &void_arg,
bool stop_others,
bool try_all_threads,
bool unwind_on_error,
bool ignore_breakpoints,
uint32_t timeout_usec,
Stream &errors,
lldb::addr_t *this_arg)
{
Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_EXPRESSIONS | LIBLLDB_LOG_STEP));
if (log)
log->Printf("== [ClangFunction::ExecuteFunction] Executing function ==");
lldb::ThreadPlanSP call_plan_sp (ClangFunction::GetThreadPlanToCallFunction (exe_ctx,
function_address,
void_arg,
errors,
stop_others,
unwind_on_error,
ignore_breakpoints,
this_arg));
if (!call_plan_sp)
return eExecutionSetupError;
// <rdar://problem/12027563> we need to make sure we record the fact that we are running an expression here
// otherwise this fact will fail to be recorded when fetching an Objective-C object description
if (exe_ctx.GetProcessPtr())
exe_ctx.GetProcessPtr()->SetRunningUserExpression(true);
ExecutionResults results = exe_ctx.GetProcessRef().RunThreadPlan (exe_ctx, call_plan_sp,
stop_others,
try_all_threads,
unwind_on_error,
ignore_breakpoints,
timeout_usec,
errors);
if (log)
{
if (results != eExecutionCompleted)
{
log->Printf("== [ClangFunction::ExecuteFunction] Execution completed abnormally ==");
}
else
{
log->Printf("== [ClangFunction::ExecuteFunction] Execution completed normally ==");
}
}
if (exe_ctx.GetProcessPtr())
exe_ctx.GetProcessPtr()->SetRunningUserExpression(false);
return results;
}
ExecutionResults
ClangFunction::ExecuteFunction(
ExecutionContext &exe_ctx,
lldb::addr_t *args_addr_ptr,
Stream &errors,
bool stop_others,
uint32_t timeout_usec,
bool try_all_threads,
bool unwind_on_error,
bool ignore_breakpoints,
Value &results)
{
using namespace clang;
ExecutionResults return_value = eExecutionSetupError;
lldb::addr_t args_addr;
if (args_addr_ptr != NULL)
args_addr = *args_addr_ptr;
else
args_addr = LLDB_INVALID_ADDRESS;
if (CompileFunction(errors) != 0)
return eExecutionSetupError;
if (args_addr == LLDB_INVALID_ADDRESS)
{
if (!InsertFunction(exe_ctx, args_addr, errors))
return eExecutionSetupError;
}
return_value = ClangFunction::ExecuteFunction (exe_ctx,
m_jit_start_addr,
args_addr,
stop_others,
try_all_threads,
unwind_on_error,
ignore_breakpoints,
timeout_usec,
errors);
if (args_addr_ptr != NULL)
*args_addr_ptr = args_addr;
if (return_value != eExecutionCompleted)
return return_value;
FetchFunctionResults(exe_ctx, args_addr, results);
if (args_addr_ptr == NULL)
DeallocateFunctionResults(exe_ctx, args_addr);
return eExecutionCompleted;
}
clang::ASTConsumer *
ClangFunction::ASTTransformer (clang::ASTConsumer *passthrough)
{
return new ASTStructExtractor(passthrough, m_wrapper_struct_name.c_str(), *this);
}
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