FunctionCaller.cpp revision 360784 
1//===-- FunctionCaller.cpp ---------------------------------------*- C++-*-===//
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/Log.h"
28#include "lldb/Utility/State.h"
29
30using namespace lldb_private;
31
32char FunctionCaller::ID;
33
34// FunctionCaller constructor
35FunctionCaller::FunctionCaller(ExecutionContextScope &exe_scope,
36                               const CompilerType &return_type,
37                               const Address &functionAddress,
38                               const ValueList &arg_value_list,
39                               const char *name)
40    : Expression(exe_scope), m_execution_unit_sp(), m_parser(),
41      m_jit_module_wp(), m_name(name ? name : "<unknown>"),
42      m_function_ptr(nullptr), m_function_addr(functionAddress),
43      m_function_return_type(return_type),
44      m_wrapper_function_name("__lldb_caller_function"),
45      m_wrapper_struct_name("__lldb_caller_struct"), m_wrapper_args_addrs(),
46      m_struct_valid(false), m_arg_values(arg_value_list), m_compiled(false),
47      m_JITted(false) {
48  m_jit_process_wp = lldb::ProcessWP(exe_scope.CalculateProcess());
49  // Can't make a FunctionCaller without a process.
50  assert(m_jit_process_wp.lock());
51}
52
53// Destructor
54FunctionCaller::~FunctionCaller() {
55  lldb::ProcessSP process_sp(m_jit_process_wp.lock());
56  if (process_sp) {
57    lldb::ModuleSP jit_module_sp(m_jit_module_wp.lock());
58    if (jit_module_sp)
59      process_sp->GetTarget().GetImages().Remove(jit_module_sp);
60  }
61}
62
63bool FunctionCaller::WriteFunctionWrapper(
64    ExecutionContext &exe_ctx, DiagnosticManager &diagnostic_manager) {
65  Process *process = exe_ctx.GetProcessPtr();
66
67  if (!process)
68    return false;
69
70  lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
71
72  if (process != jit_process_sp.get())
73    return false;
74
75  if (!m_compiled)
76    return false;
77
78  if (m_JITted)
79    return true;
80
81  bool can_interpret = false; // should stay that way
82
83  Status jit_error(m_parser->PrepareForExecution(
84      m_jit_start_addr, m_jit_end_addr, m_execution_unit_sp, exe_ctx,
85      can_interpret, eExecutionPolicyAlways));
86
87  if (!jit_error.Success()) {
88    diagnostic_manager.Printf(eDiagnosticSeverityError,
89                              "Error in PrepareForExecution: %s.",
90                              jit_error.AsCString());
91    return false;
92  }
93
94  if (m_parser->GetGenerateDebugInfo()) {
95    lldb::ModuleSP jit_module_sp(m_execution_unit_sp->GetJITModule());
96
97    if (jit_module_sp) {
98      ConstString const_func_name(FunctionName());
99      FileSpec jit_file;
100      jit_file.GetFilename() = const_func_name;
101      jit_module_sp->SetFileSpecAndObjectName(jit_file, ConstString());
102      m_jit_module_wp = jit_module_sp;
103      process->GetTarget().GetImages().Append(jit_module_sp,
104                                              true /* notify */);
105    }
106  }
107  if (process && m_jit_start_addr)
108    m_jit_process_wp = process->shared_from_this();
109
110  m_JITted = true;
111
112  return true;
113}
114
115bool FunctionCaller::WriteFunctionArguments(
116    ExecutionContext &exe_ctx, lldb::addr_t &args_addr_ref,
117    DiagnosticManager &diagnostic_manager) {
118  return WriteFunctionArguments(exe_ctx, args_addr_ref, m_arg_values,
119                                diagnostic_manager);
120}
121
122// FIXME: Assure that the ValueList we were passed in is consistent with the one
123// that defined this function.
124
125bool FunctionCaller::WriteFunctionArguments(
126    ExecutionContext &exe_ctx, lldb::addr_t &args_addr_ref,
127    ValueList &arg_values, DiagnosticManager &diagnostic_manager) {
128  // All the information to reconstruct the struct is provided by the
129  // StructExtractor.
130  if (!m_struct_valid) {
131    diagnostic_manager.PutString(eDiagnosticSeverityError,
132                                 "Argument information was not correctly "
133                                 "parsed, so the function cannot be called.");
134    return false;
135  }
136
137  Status error;
138  lldb::ExpressionResults return_value = lldb::eExpressionSetupError;
139
140  Process *process = exe_ctx.GetProcessPtr();
141
142  if (process == nullptr)
143    return return_value;
144
145  lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
146
147  if (process != jit_process_sp.get())
148    return false;
149
150  if (args_addr_ref == LLDB_INVALID_ADDRESS) {
151    args_addr_ref = process->AllocateMemory(
152        m_struct_size, lldb::ePermissionsReadable | lldb::ePermissionsWritable,
153        error);
154    if (args_addr_ref == LLDB_INVALID_ADDRESS)
155      return false;
156    m_wrapper_args_addrs.push_back(args_addr_ref);
157  } else {
158    // Make sure this is an address that we've already handed out.
159    if (find(m_wrapper_args_addrs.begin(), m_wrapper_args_addrs.end(),
160             args_addr_ref) == m_wrapper_args_addrs.end()) {
161      return false;
162    }
163  }
164
165  // TODO: verify fun_addr needs to be a callable address
166  Scalar fun_addr(
167      m_function_addr.GetCallableLoadAddress(exe_ctx.GetTargetPtr()));
168  uint64_t first_offset = m_member_offsets[0];
169  process->WriteScalarToMemory(args_addr_ref + first_offset, fun_addr,
170                               process->GetAddressByteSize(), error);
171
172  // FIXME: We will need to extend this for Variadic functions.
173
174  Status value_error;
175
176  size_t num_args = arg_values.GetSize();
177  if (num_args != m_arg_values.GetSize()) {
178    diagnostic_manager.Printf(
179        eDiagnosticSeverityError,
180        "Wrong number of arguments - was: %" PRIu64 " should be: %" PRIu64 "",
181        (uint64_t)num_args, (uint64_t)m_arg_values.GetSize());
182    return false;
183  }
184
185  for (size_t i = 0; i < num_args; i++) {
186    // FIXME: We should sanity check sizes.
187
188    uint64_t offset = m_member_offsets[i + 1]; // Clang sizes are in bytes.
189    Value *arg_value = arg_values.GetValueAtIndex(i);
190
191    // FIXME: For now just do scalars:
192
193    // Special case: if it's a pointer, don't do anything (the ABI supports
194    // passing cstrings)
195
196    if (arg_value->GetValueType() == Value::eValueTypeHostAddress &&
197        arg_value->GetContextType() == Value::eContextTypeInvalid &&
198        arg_value->GetCompilerType().IsPointerType())
199      continue;
200
201    const Scalar &arg_scalar = arg_value->ResolveValue(&exe_ctx);
202
203    if (!process->WriteScalarToMemory(args_addr_ref + offset, arg_scalar,
204                                      arg_scalar.GetByteSize(), error))
205      return false;
206  }
207
208  return true;
209}
210
211bool FunctionCaller::InsertFunction(ExecutionContext &exe_ctx,
212                                    lldb::addr_t &args_addr_ref,
213                                    DiagnosticManager &diagnostic_manager) {
214  if (CompileFunction(exe_ctx.GetThreadSP(), diagnostic_manager) != 0)
215    return false;
216  if (!WriteFunctionWrapper(exe_ctx, diagnostic_manager))
217    return false;
218  if (!WriteFunctionArguments(exe_ctx, args_addr_ref, diagnostic_manager))
219    return false;
220
221  Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
222  LLDB_LOGF(log, "Call Address: 0x%" PRIx64 " Struct Address: 0x%" PRIx64 ".\n",
223            m_jit_start_addr, args_addr_ref);
224
225  return true;
226}
227
228lldb::ThreadPlanSP FunctionCaller::GetThreadPlanToCallFunction(
229    ExecutionContext &exe_ctx, lldb::addr_t args_addr,
230    const EvaluateExpressionOptions &options,
231    DiagnosticManager &diagnostic_manager) {
232  Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_EXPRESSIONS |
233                                                  LIBLLDB_LOG_STEP));
234
235  LLDB_LOGF(log,
236            "-- [FunctionCaller::GetThreadPlanToCallFunction] Creating "
237            "thread plan to call function \"%s\" --",
238            m_name.c_str());
239
240  // FIXME: Use the errors Stream for better error reporting.
241  Thread *thread = exe_ctx.GetThreadPtr();
242  if (thread == nullptr) {
243    diagnostic_manager.PutString(
244        eDiagnosticSeverityError,
245        "Can't call a function without a valid thread.");
246    return nullptr;
247  }
248
249  // Okay, now run the function:
250
251  Address wrapper_address(m_jit_start_addr);
252
253  lldb::addr_t args = {args_addr};
254
255  lldb::ThreadPlanSP new_plan_sp(new ThreadPlanCallFunction(
256      *thread, wrapper_address, CompilerType(), args, options));
257  new_plan_sp->SetIsMasterPlan(true);
258  new_plan_sp->SetOkayToDiscard(false);
259  return new_plan_sp;
260}
261
262bool FunctionCaller::FetchFunctionResults(ExecutionContext &exe_ctx,
263                                          lldb::addr_t args_addr,
264                                          Value &ret_value) {
265  // Read the return value - it is the last field in the struct:
266  // FIXME: How does clang tell us there's no return value?  We need to handle
267  // that case.
268  // FIXME: Create our ThreadPlanCallFunction with the return CompilerType, and
269  // then use GetReturnValueObject
270  // to fetch the value.  That way we can fetch any values we need.
271
272  Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_EXPRESSIONS |
273                                                  LIBLLDB_LOG_STEP));
274
275  LLDB_LOGF(log,
276            "-- [FunctionCaller::FetchFunctionResults] Fetching function "
277            "results for \"%s\"--",
278            m_name.c_str());
279
280  Process *process = exe_ctx.GetProcessPtr();
281
282  if (process == nullptr)
283    return false;
284
285  lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
286
287  if (process != jit_process_sp.get())
288    return false;
289
290  Status error;
291  ret_value.GetScalar() = process->ReadUnsignedIntegerFromMemory(
292      args_addr + m_return_offset, m_return_size, 0, error);
293
294  if (error.Fail())
295    return false;
296
297  ret_value.SetCompilerType(m_function_return_type);
298  ret_value.SetValueType(Value::eValueTypeScalar);
299  return true;
300}
301
302void FunctionCaller::DeallocateFunctionResults(ExecutionContext &exe_ctx,
303                                               lldb::addr_t args_addr) {
304  std::list<lldb::addr_t>::iterator pos;
305  pos = std::find(m_wrapper_args_addrs.begin(), m_wrapper_args_addrs.end(),
306                  args_addr);
307  if (pos != m_wrapper_args_addrs.end())
308    m_wrapper_args_addrs.erase(pos);
309
310  exe_ctx.GetProcessRef().DeallocateMemory(args_addr);
311}
312
313lldb::ExpressionResults FunctionCaller::ExecuteFunction(
314    ExecutionContext &exe_ctx, lldb::addr_t *args_addr_ptr,
315    const EvaluateExpressionOptions &options,
316    DiagnosticManager &diagnostic_manager, Value &results) {
317  lldb::ExpressionResults return_value = lldb::eExpressionSetupError;
318
319  // FunctionCaller::ExecuteFunction execution is always just to get the
320  // result. Do make sure we ignore breakpoints, unwind on error, and don't try
321  // to debug it.
322  EvaluateExpressionOptions real_options = options;
323  real_options.SetDebug(false);
324  real_options.SetUnwindOnError(true);
325  real_options.SetIgnoreBreakpoints(true);
326
327  lldb::addr_t args_addr;
328
329  if (args_addr_ptr != nullptr)
330    args_addr = *args_addr_ptr;
331  else
332    args_addr = LLDB_INVALID_ADDRESS;
333
334  if (CompileFunction(exe_ctx.GetThreadSP(), diagnostic_manager) != 0)
335    return lldb::eExpressionSetupError;
336
337  if (args_addr == LLDB_INVALID_ADDRESS) {
338    if (!InsertFunction(exe_ctx, args_addr, diagnostic_manager))
339      return lldb::eExpressionSetupError;
340  }
341
342  Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_EXPRESSIONS |
343                                                  LIBLLDB_LOG_STEP));
344
345  LLDB_LOGF(log,
346            "== [FunctionCaller::ExecuteFunction] Executing function \"%s\" ==",
347            m_name.c_str());
348
349  lldb::ThreadPlanSP call_plan_sp = GetThreadPlanToCallFunction(
350      exe_ctx, args_addr, real_options, diagnostic_manager);
351  if (!call_plan_sp)
352    return lldb::eExpressionSetupError;
353
354  // We need to make sure we record the fact that we are running an expression
355  // here otherwise this fact will fail to be recorded when fetching an
356  // Objective-C object description
357  if (exe_ctx.GetProcessPtr())
358    exe_ctx.GetProcessPtr()->SetRunningUserExpression(true);
359
360  return_value = exe_ctx.GetProcessRef().RunThreadPlan(
361      exe_ctx, call_plan_sp, real_options, diagnostic_manager);
362
363  if (log) {
364    if (return_value != lldb::eExpressionCompleted) {
365      LLDB_LOGF(log,
366                "== [FunctionCaller::ExecuteFunction] Execution of \"%s\" "
367                "completed abnormally ==",
368                m_name.c_str());
369    } else {
370      LLDB_LOGF(log,
371                "== [FunctionCaller::ExecuteFunction] Execution of \"%s\" "
372                "completed normally ==",
373                m_name.c_str());
374    }
375  }
376
377  if (exe_ctx.GetProcessPtr())
378    exe_ctx.GetProcessPtr()->SetRunningUserExpression(false);
379
380  if (args_addr_ptr != nullptr)
381    *args_addr_ptr = args_addr;
382
383  if (return_value != lldb::eExpressionCompleted)
384    return return_value;
385
386  FetchFunctionResults(exe_ctx, args_addr, results);
387
388  if (args_addr_ptr == nullptr)
389    DeallocateFunctionResults(exe_ctx, args_addr);
390
391  return lldb::eExpressionCompleted;
392}
393