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