1//===-- FunctionCaller.cpp ------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9
10#include "lldb/Expression/FunctionCaller.h"
11#include "lldb/Core/Module.h"
12#include "lldb/Core/ValueObject.h"
13#include "lldb/Core/ValueObjectList.h"
14#include "lldb/Expression/DiagnosticManager.h"
15#include "lldb/Expression/IRExecutionUnit.h"
16#include "lldb/Interpreter/CommandReturnObject.h"
17#include "lldb/Symbol/Function.h"
18#include "lldb/Symbol/Type.h"
19#include "lldb/Target/ExecutionContext.h"
20#include "lldb/Target/Process.h"
21#include "lldb/Target/RegisterContext.h"
22#include "lldb/Target/Target.h"
23#include "lldb/Target/Thread.h"
24#include "lldb/Target/ThreadPlan.h"
25#include "lldb/Target/ThreadPlanCallFunction.h"
26#include "lldb/Utility/DataExtractor.h"
27#include "lldb/Utility/LLDBLog.h"
28#include "lldb/Utility/Log.h"
29#include "lldb/Utility/State.h"
30
31using namespace lldb_private;
32
33char FunctionCaller::ID;
34
35// FunctionCaller constructor
36FunctionCaller::FunctionCaller(ExecutionContextScope &exe_scope,
37                               const CompilerType &return_type,
38                               const Address &functionAddress,
39                               const ValueList &arg_value_list,
40                               const char *name)
41    : Expression(exe_scope), m_execution_unit_sp(), m_parser(),
42      m_jit_module_wp(), m_name(name ? name : "<unknown>"),
43      m_function_ptr(nullptr), m_function_addr(functionAddress),
44      m_function_return_type(return_type),
45      m_wrapper_function_name("__lldb_caller_function"),
46      m_wrapper_struct_name("__lldb_caller_struct"), m_wrapper_args_addrs(),
47      m_struct_valid(false), m_struct_size(0), m_return_size(0),
48      m_return_offset(0), m_arg_values(arg_value_list), m_compiled(false),
49      m_JITted(false) {
50  m_jit_process_wp = lldb::ProcessWP(exe_scope.CalculateProcess());
51  // Can't make a FunctionCaller without a process.
52  assert(m_jit_process_wp.lock());
53}
54
55// Destructor
56FunctionCaller::~FunctionCaller() {
57  lldb::ProcessSP process_sp(m_jit_process_wp.lock());
58  if (process_sp) {
59    lldb::ModuleSP jit_module_sp(m_jit_module_wp.lock());
60    if (jit_module_sp)
61      process_sp->GetTarget().GetImages().Remove(jit_module_sp);
62  }
63}
64
65bool FunctionCaller::WriteFunctionWrapper(
66    ExecutionContext &exe_ctx, DiagnosticManager &diagnostic_manager) {
67  Process *process = exe_ctx.GetProcessPtr();
68
69  if (!process) {
70    diagnostic_manager.Printf(eDiagnosticSeverityError, "no process.");
71    return false;
72  }
73
74  lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
75
76  if (process != jit_process_sp.get()) {
77    diagnostic_manager.Printf(eDiagnosticSeverityError,
78                             "process does not match the stored process.");
79    return false;
80  }
81
82  if (process->GetState() != lldb::eStateStopped) {
83    diagnostic_manager.Printf(eDiagnosticSeverityError,
84                              "process is not stopped");
85    return false;
86  }
87
88  if (!m_compiled) {
89    diagnostic_manager.Printf(eDiagnosticSeverityError,
90                              "function not compiled");
91    return false;
92  }
93
94  if (m_JITted)
95    return true;
96
97  bool can_interpret = false; // should stay that way
98
99  Status jit_error(m_parser->PrepareForExecution(
100      m_jit_start_addr, m_jit_end_addr, m_execution_unit_sp, exe_ctx,
101      can_interpret, eExecutionPolicyAlways));
102
103  if (!jit_error.Success()) {
104    diagnostic_manager.Printf(eDiagnosticSeverityError,
105                              "Error in PrepareForExecution: %s.",
106                              jit_error.AsCString());
107    return false;
108  }
109
110  if (m_parser->GetGenerateDebugInfo()) {
111    lldb::ModuleSP jit_module_sp(m_execution_unit_sp->GetJITModule());
112
113    if (jit_module_sp) {
114      ConstString const_func_name(FunctionName());
115      FileSpec jit_file;
116      jit_file.SetFilename(const_func_name);
117      jit_module_sp->SetFileSpecAndObjectName(jit_file, ConstString());
118      m_jit_module_wp = jit_module_sp;
119      process->GetTarget().GetImages().Append(jit_module_sp,
120                                              true /* notify */);
121    }
122  }
123  if (process && m_jit_start_addr)
124    m_jit_process_wp = process->shared_from_this();
125
126  m_JITted = true;
127
128  return true;
129}
130
131bool FunctionCaller::WriteFunctionArguments(
132    ExecutionContext &exe_ctx, lldb::addr_t &args_addr_ref,
133    DiagnosticManager &diagnostic_manager) {
134  return WriteFunctionArguments(exe_ctx, args_addr_ref, m_arg_values,
135                                diagnostic_manager);
136}
137
138// FIXME: Assure that the ValueList we were passed in is consistent with the one
139// that defined this function.
140
141bool FunctionCaller::WriteFunctionArguments(
142    ExecutionContext &exe_ctx, lldb::addr_t &args_addr_ref,
143    ValueList &arg_values, DiagnosticManager &diagnostic_manager) {
144  // All the information to reconstruct the struct is provided by the
145  // StructExtractor.
146  if (!m_struct_valid) {
147    diagnostic_manager.PutString(eDiagnosticSeverityError,
148                                 "Argument information was not correctly "
149                                 "parsed, so the function cannot be called.");
150    return false;
151  }
152
153  Status error;
154  lldb::ExpressionResults return_value = lldb::eExpressionSetupError;
155
156  Process *process = exe_ctx.GetProcessPtr();
157
158  if (process == nullptr)
159    return return_value;
160
161  lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
162
163  if (process != jit_process_sp.get())
164    return false;
165
166  if (args_addr_ref == LLDB_INVALID_ADDRESS) {
167    args_addr_ref = process->AllocateMemory(
168        m_struct_size, lldb::ePermissionsReadable | lldb::ePermissionsWritable,
169        error);
170    if (args_addr_ref == LLDB_INVALID_ADDRESS)
171      return false;
172    m_wrapper_args_addrs.push_back(args_addr_ref);
173  } else {
174    // Make sure this is an address that we've already handed out.
175    if (find(m_wrapper_args_addrs.begin(), m_wrapper_args_addrs.end(),
176             args_addr_ref) == m_wrapper_args_addrs.end()) {
177      return false;
178    }
179  }
180
181  // TODO: verify fun_addr needs to be a callable address
182  Scalar fun_addr(
183      m_function_addr.GetCallableLoadAddress(exe_ctx.GetTargetPtr()));
184  uint64_t first_offset = m_member_offsets[0];
185  process->WriteScalarToMemory(args_addr_ref + first_offset, fun_addr,
186                               process->GetAddressByteSize(), error);
187
188  // FIXME: We will need to extend this for Variadic functions.
189
190  Status value_error;
191
192  size_t num_args = arg_values.GetSize();
193  if (num_args != m_arg_values.GetSize()) {
194    diagnostic_manager.Printf(
195        eDiagnosticSeverityError,
196        "Wrong number of arguments - was: %" PRIu64 " should be: %" PRIu64 "",
197        (uint64_t)num_args, (uint64_t)m_arg_values.GetSize());
198    return false;
199  }
200
201  for (size_t i = 0; i < num_args; i++) {
202    // FIXME: We should sanity check sizes.
203
204    uint64_t offset = m_member_offsets[i + 1]; // Clang sizes are in bytes.
205    Value *arg_value = arg_values.GetValueAtIndex(i);
206
207    // FIXME: For now just do scalars:
208
209    // Special case: if it's a pointer, don't do anything (the ABI supports
210    // passing cstrings)
211
212    if (arg_value->GetValueType() == Value::ValueType::HostAddress &&
213        arg_value->GetContextType() == Value::ContextType::Invalid &&
214        arg_value->GetCompilerType().IsPointerType())
215      continue;
216
217    const Scalar &arg_scalar = arg_value->ResolveValue(&exe_ctx);
218
219    if (!process->WriteScalarToMemory(args_addr_ref + offset, arg_scalar,
220                                      arg_scalar.GetByteSize(), error))
221      return false;
222  }
223
224  return true;
225}
226
227bool FunctionCaller::InsertFunction(ExecutionContext &exe_ctx,
228                                    lldb::addr_t &args_addr_ref,
229                                    DiagnosticManager &diagnostic_manager) {
230  // Since we might need to call allocate memory and maybe call code to make
231  // the caller, we need to be stopped.
232  Process *process = exe_ctx.GetProcessPtr();
233  if (!process) {
234    diagnostic_manager.PutString(eDiagnosticSeverityError, "no process");
235    return false;
236  }
237  if (process->GetState() != lldb::eStateStopped) {
238    diagnostic_manager.PutString(eDiagnosticSeverityError, "process running");
239    return false;
240  }
241  if (CompileFunction(exe_ctx.GetThreadSP(), diagnostic_manager) != 0)
242    return false;
243  if (!WriteFunctionWrapper(exe_ctx, diagnostic_manager))
244    return false;
245  if (!WriteFunctionArguments(exe_ctx, args_addr_ref, diagnostic_manager))
246    return false;
247
248  Log *log = GetLog(LLDBLog::Step);
249  LLDB_LOGF(log, "Call Address: 0x%" PRIx64 " Struct Address: 0x%" PRIx64 ".\n",
250            m_jit_start_addr, args_addr_ref);
251
252  return true;
253}
254
255lldb::ThreadPlanSP FunctionCaller::GetThreadPlanToCallFunction(
256    ExecutionContext &exe_ctx, lldb::addr_t args_addr,
257    const EvaluateExpressionOptions &options,
258    DiagnosticManager &diagnostic_manager) {
259  Log *log(GetLog(LLDBLog::Expressions | LLDBLog::Step));
260
261  LLDB_LOGF(log,
262            "-- [FunctionCaller::GetThreadPlanToCallFunction] Creating "
263            "thread plan to call function \"%s\" --",
264            m_name.c_str());
265
266  // FIXME: Use the errors Stream for better error reporting.
267  Thread *thread = exe_ctx.GetThreadPtr();
268  if (thread == nullptr) {
269    diagnostic_manager.PutString(
270        eDiagnosticSeverityError,
271        "Can't call a function without a valid thread.");
272    return nullptr;
273  }
274
275  // Okay, now run the function:
276
277  Address wrapper_address(m_jit_start_addr);
278
279  lldb::addr_t args = {args_addr};
280
281  lldb::ThreadPlanSP new_plan_sp(new ThreadPlanCallFunction(
282      *thread, wrapper_address, CompilerType(), args, options));
283  new_plan_sp->SetIsControllingPlan(true);
284  new_plan_sp->SetOkayToDiscard(false);
285  return new_plan_sp;
286}
287
288bool FunctionCaller::FetchFunctionResults(ExecutionContext &exe_ctx,
289                                          lldb::addr_t args_addr,
290                                          Value &ret_value) {
291  // Read the return value - it is the last field in the struct:
292  // FIXME: How does clang tell us there's no return value?  We need to handle
293  // that case.
294  // FIXME: Create our ThreadPlanCallFunction with the return CompilerType, and
295  // then use GetReturnValueObject
296  // to fetch the value.  That way we can fetch any values we need.
297
298  Log *log(GetLog(LLDBLog::Expressions | LLDBLog::Step));
299
300  LLDB_LOGF(log,
301            "-- [FunctionCaller::FetchFunctionResults] Fetching function "
302            "results for \"%s\"--",
303            m_name.c_str());
304
305  Process *process = exe_ctx.GetProcessPtr();
306
307  if (process == nullptr)
308    return false;
309
310  lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
311
312  if (process != jit_process_sp.get())
313    return false;
314
315  Status error;
316  ret_value.GetScalar() = process->ReadUnsignedIntegerFromMemory(
317      args_addr + m_return_offset, m_return_size, 0, error);
318
319  if (error.Fail())
320    return false;
321
322  ret_value.SetCompilerType(m_function_return_type);
323  ret_value.SetValueType(Value::ValueType::Scalar);
324  return true;
325}
326
327void FunctionCaller::DeallocateFunctionResults(ExecutionContext &exe_ctx,
328                                               lldb::addr_t args_addr) {
329  std::list<lldb::addr_t>::iterator pos;
330  pos = std::find(m_wrapper_args_addrs.begin(), m_wrapper_args_addrs.end(),
331                  args_addr);
332  if (pos != m_wrapper_args_addrs.end())
333    m_wrapper_args_addrs.erase(pos);
334
335  exe_ctx.GetProcessRef().DeallocateMemory(args_addr);
336}
337
338lldb::ExpressionResults FunctionCaller::ExecuteFunction(
339    ExecutionContext &exe_ctx, lldb::addr_t *args_addr_ptr,
340    const EvaluateExpressionOptions &options,
341    DiagnosticManager &diagnostic_manager, Value &results) {
342  lldb::ExpressionResults return_value = lldb::eExpressionSetupError;
343
344  // FunctionCaller::ExecuteFunction execution is always just to get the
345  // result. Unless explicitly asked for, ignore breakpoints and unwind on
346  // error.
347  const bool enable_debugging =
348      exe_ctx.GetTargetPtr() &&
349      exe_ctx.GetTargetPtr()->GetDebugUtilityExpression();
350  EvaluateExpressionOptions real_options = options;
351  real_options.SetDebug(false); // This halts the expression for debugging.
352  real_options.SetGenerateDebugInfo(enable_debugging);
353  real_options.SetUnwindOnError(!enable_debugging);
354  real_options.SetIgnoreBreakpoints(!enable_debugging);
355
356  lldb::addr_t args_addr;
357
358  if (args_addr_ptr != nullptr)
359    args_addr = *args_addr_ptr;
360  else
361    args_addr = LLDB_INVALID_ADDRESS;
362
363  if (CompileFunction(exe_ctx.GetThreadSP(), diagnostic_manager) != 0)
364    return lldb::eExpressionSetupError;
365
366  if (args_addr == LLDB_INVALID_ADDRESS) {
367    if (!InsertFunction(exe_ctx, args_addr, diagnostic_manager))
368      return lldb::eExpressionSetupError;
369  }
370
371  Log *log(GetLog(LLDBLog::Expressions | LLDBLog::Step));
372
373  LLDB_LOGF(log,
374            "== [FunctionCaller::ExecuteFunction] Executing function \"%s\" ==",
375            m_name.c_str());
376
377  lldb::ThreadPlanSP call_plan_sp = GetThreadPlanToCallFunction(
378      exe_ctx, args_addr, real_options, diagnostic_manager);
379  if (!call_plan_sp)
380    return lldb::eExpressionSetupError;
381
382  // We need to make sure we record the fact that we are running an expression
383  // here otherwise this fact will fail to be recorded when fetching an
384  // Objective-C object description
385  if (exe_ctx.GetProcessPtr())
386    exe_ctx.GetProcessPtr()->SetRunningUserExpression(true);
387
388  return_value = exe_ctx.GetProcessRef().RunThreadPlan(
389      exe_ctx, call_plan_sp, real_options, diagnostic_manager);
390
391  if (log) {
392    if (return_value != lldb::eExpressionCompleted) {
393      LLDB_LOGF(log,
394                "== [FunctionCaller::ExecuteFunction] Execution of \"%s\" "
395                "completed abnormally: %s ==",
396                m_name.c_str(),
397                Process::ExecutionResultAsCString(return_value));
398    } else {
399      LLDB_LOGF(log,
400                "== [FunctionCaller::ExecuteFunction] Execution of \"%s\" "
401                "completed normally ==",
402                m_name.c_str());
403    }
404  }
405
406  if (exe_ctx.GetProcessPtr())
407    exe_ctx.GetProcessPtr()->SetRunningUserExpression(false);
408
409  if (args_addr_ptr != nullptr)
410    *args_addr_ptr = args_addr;
411
412  if (return_value != lldb::eExpressionCompleted)
413    return return_value;
414
415  FetchFunctionResults(exe_ctx, args_addr, results);
416
417  if (args_addr_ptr == nullptr)
418    DeallocateFunctionResults(exe_ctx, args_addr);
419
420  return lldb::eExpressionCompleted;
421}
422