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
31 using namespace lldb_private;
32
33 char FunctionCaller::ID;
34
35 // FunctionCaller constructor
FunctionCaller(ExecutionContextScope & exe_scope,const CompilerType & return_type,const Address & functionAddress,const ValueList & arg_value_list,const char * name)36 FunctionCaller::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_arg_values(arg_value_list), m_compiled(false),
48 m_JITted(false) {
49 m_jit_process_wp = lldb::ProcessWP(exe_scope.CalculateProcess());
50 // Can't make a FunctionCaller without a process.
51 assert(m_jit_process_wp.lock());
52 }
53
54 // Destructor
~FunctionCaller()55 FunctionCaller::~FunctionCaller() {
56 lldb::ProcessSP process_sp(m_jit_process_wp.lock());
57 if (process_sp) {
58 lldb::ModuleSP jit_module_sp(m_jit_module_wp.lock());
59 if (jit_module_sp)
60 process_sp->GetTarget().GetImages().Remove(jit_module_sp);
61 }
62 }
63
WriteFunctionWrapper(ExecutionContext & exe_ctx,DiagnosticManager & diagnostic_manager)64 bool FunctionCaller::WriteFunctionWrapper(
65 ExecutionContext &exe_ctx, DiagnosticManager &diagnostic_manager) {
66 Process *process = exe_ctx.GetProcessPtr();
67
68 if (!process)
69 return false;
70
71 lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
72
73 if (process != jit_process_sp.get())
74 return false;
75
76 if (!m_compiled)
77 return false;
78
79 if (m_JITted)
80 return true;
81
82 bool can_interpret = false; // should stay that way
83
84 Status jit_error(m_parser->PrepareForExecution(
85 m_jit_start_addr, m_jit_end_addr, m_execution_unit_sp, exe_ctx,
86 can_interpret, eExecutionPolicyAlways));
87
88 if (!jit_error.Success()) {
89 diagnostic_manager.Printf(eDiagnosticSeverityError,
90 "Error in PrepareForExecution: %s.",
91 jit_error.AsCString());
92 return false;
93 }
94
95 if (m_parser->GetGenerateDebugInfo()) {
96 lldb::ModuleSP jit_module_sp(m_execution_unit_sp->GetJITModule());
97
98 if (jit_module_sp) {
99 ConstString const_func_name(FunctionName());
100 FileSpec jit_file;
101 jit_file.GetFilename() = const_func_name;
102 jit_module_sp->SetFileSpecAndObjectName(jit_file, ConstString());
103 m_jit_module_wp = jit_module_sp;
104 process->GetTarget().GetImages().Append(jit_module_sp,
105 true /* notify */);
106 }
107 }
108 if (process && m_jit_start_addr)
109 m_jit_process_wp = process->shared_from_this();
110
111 m_JITted = true;
112
113 return true;
114 }
115
WriteFunctionArguments(ExecutionContext & exe_ctx,lldb::addr_t & args_addr_ref,DiagnosticManager & diagnostic_manager)116 bool FunctionCaller::WriteFunctionArguments(
117 ExecutionContext &exe_ctx, lldb::addr_t &args_addr_ref,
118 DiagnosticManager &diagnostic_manager) {
119 return WriteFunctionArguments(exe_ctx, args_addr_ref, m_arg_values,
120 diagnostic_manager);
121 }
122
123 // FIXME: Assure that the ValueList we were passed in is consistent with the one
124 // that defined this function.
125
WriteFunctionArguments(ExecutionContext & exe_ctx,lldb::addr_t & args_addr_ref,ValueList & arg_values,DiagnosticManager & diagnostic_manager)126 bool FunctionCaller::WriteFunctionArguments(
127 ExecutionContext &exe_ctx, lldb::addr_t &args_addr_ref,
128 ValueList &arg_values, DiagnosticManager &diagnostic_manager) {
129 // All the information to reconstruct the struct is provided by the
130 // StructExtractor.
131 if (!m_struct_valid) {
132 diagnostic_manager.PutString(eDiagnosticSeverityError,
133 "Argument information was not correctly "
134 "parsed, so the function cannot be called.");
135 return false;
136 }
137
138 Status error;
139 lldb::ExpressionResults return_value = lldb::eExpressionSetupError;
140
141 Process *process = exe_ctx.GetProcessPtr();
142
143 if (process == nullptr)
144 return return_value;
145
146 lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
147
148 if (process != jit_process_sp.get())
149 return false;
150
151 if (args_addr_ref == LLDB_INVALID_ADDRESS) {
152 args_addr_ref = process->AllocateMemory(
153 m_struct_size, lldb::ePermissionsReadable | lldb::ePermissionsWritable,
154 error);
155 if (args_addr_ref == LLDB_INVALID_ADDRESS)
156 return false;
157 m_wrapper_args_addrs.push_back(args_addr_ref);
158 } else {
159 // Make sure this is an address that we've already handed out.
160 if (find(m_wrapper_args_addrs.begin(), m_wrapper_args_addrs.end(),
161 args_addr_ref) == m_wrapper_args_addrs.end()) {
162 return false;
163 }
164 }
165
166 // TODO: verify fun_addr needs to be a callable address
167 Scalar fun_addr(
168 m_function_addr.GetCallableLoadAddress(exe_ctx.GetTargetPtr()));
169 uint64_t first_offset = m_member_offsets[0];
170 process->WriteScalarToMemory(args_addr_ref + first_offset, fun_addr,
171 process->GetAddressByteSize(), error);
172
173 // FIXME: We will need to extend this for Variadic functions.
174
175 Status value_error;
176
177 size_t num_args = arg_values.GetSize();
178 if (num_args != m_arg_values.GetSize()) {
179 diagnostic_manager.Printf(
180 eDiagnosticSeverityError,
181 "Wrong number of arguments - was: %" PRIu64 " should be: %" PRIu64 "",
182 (uint64_t)num_args, (uint64_t)m_arg_values.GetSize());
183 return false;
184 }
185
186 for (size_t i = 0; i < num_args; i++) {
187 // FIXME: We should sanity check sizes.
188
189 uint64_t offset = m_member_offsets[i + 1]; // Clang sizes are in bytes.
190 Value *arg_value = arg_values.GetValueAtIndex(i);
191
192 // FIXME: For now just do scalars:
193
194 // Special case: if it's a pointer, don't do anything (the ABI supports
195 // passing cstrings)
196
197 if (arg_value->GetValueType() == Value::ValueType::HostAddress &&
198 arg_value->GetContextType() == Value::ContextType::Invalid &&
199 arg_value->GetCompilerType().IsPointerType())
200 continue;
201
202 const Scalar &arg_scalar = arg_value->ResolveValue(&exe_ctx);
203
204 if (!process->WriteScalarToMemory(args_addr_ref + offset, arg_scalar,
205 arg_scalar.GetByteSize(), error))
206 return false;
207 }
208
209 return true;
210 }
211
InsertFunction(ExecutionContext & exe_ctx,lldb::addr_t & args_addr_ref,DiagnosticManager & diagnostic_manager)212 bool FunctionCaller::InsertFunction(ExecutionContext &exe_ctx,
213 lldb::addr_t &args_addr_ref,
214 DiagnosticManager &diagnostic_manager) {
215 if (CompileFunction(exe_ctx.GetThreadSP(), diagnostic_manager) != 0)
216 return false;
217 if (!WriteFunctionWrapper(exe_ctx, diagnostic_manager))
218 return false;
219 if (!WriteFunctionArguments(exe_ctx, args_addr_ref, diagnostic_manager))
220 return false;
221
222 Log *log = GetLog(LLDBLog::Step);
223 LLDB_LOGF(log, "Call Address: 0x%" PRIx64 " Struct Address: 0x%" PRIx64 ".\n",
224 m_jit_start_addr, args_addr_ref);
225
226 return true;
227 }
228
GetThreadPlanToCallFunction(ExecutionContext & exe_ctx,lldb::addr_t args_addr,const EvaluateExpressionOptions & options,DiagnosticManager & diagnostic_manager)229 lldb::ThreadPlanSP FunctionCaller::GetThreadPlanToCallFunction(
230 ExecutionContext &exe_ctx, lldb::addr_t args_addr,
231 const EvaluateExpressionOptions &options,
232 DiagnosticManager &diagnostic_manager) {
233 Log *log(GetLog(LLDBLog::Expressions | LLDBLog::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->SetIsControllingPlan(true);
258 new_plan_sp->SetOkayToDiscard(false);
259 return new_plan_sp;
260 }
261
FetchFunctionResults(ExecutionContext & exe_ctx,lldb::addr_t args_addr,Value & ret_value)262 bool 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(GetLog(LLDBLog::Expressions | LLDBLog::Step));
273
274 LLDB_LOGF(log,
275 "-- [FunctionCaller::FetchFunctionResults] Fetching function "
276 "results for \"%s\"--",
277 m_name.c_str());
278
279 Process *process = exe_ctx.GetProcessPtr();
280
281 if (process == nullptr)
282 return false;
283
284 lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
285
286 if (process != jit_process_sp.get())
287 return false;
288
289 Status error;
290 ret_value.GetScalar() = process->ReadUnsignedIntegerFromMemory(
291 args_addr + m_return_offset, m_return_size, 0, error);
292
293 if (error.Fail())
294 return false;
295
296 ret_value.SetCompilerType(m_function_return_type);
297 ret_value.SetValueType(Value::ValueType::Scalar);
298 return true;
299 }
300
DeallocateFunctionResults(ExecutionContext & exe_ctx,lldb::addr_t args_addr)301 void FunctionCaller::DeallocateFunctionResults(ExecutionContext &exe_ctx,
302 lldb::addr_t args_addr) {
303 std::list<lldb::addr_t>::iterator pos;
304 pos = std::find(m_wrapper_args_addrs.begin(), m_wrapper_args_addrs.end(),
305 args_addr);
306 if (pos != m_wrapper_args_addrs.end())
307 m_wrapper_args_addrs.erase(pos);
308
309 exe_ctx.GetProcessRef().DeallocateMemory(args_addr);
310 }
311
ExecuteFunction(ExecutionContext & exe_ctx,lldb::addr_t * args_addr_ptr,const EvaluateExpressionOptions & options,DiagnosticManager & diagnostic_manager,Value & results)312 lldb::ExpressionResults FunctionCaller::ExecuteFunction(
313 ExecutionContext &exe_ctx, lldb::addr_t *args_addr_ptr,
314 const EvaluateExpressionOptions &options,
315 DiagnosticManager &diagnostic_manager, Value &results) {
316 lldb::ExpressionResults return_value = lldb::eExpressionSetupError;
317
318 // FunctionCaller::ExecuteFunction execution is always just to get the
319 // result. Unless explicitly asked for, ignore breakpoints and unwind on
320 // error.
321 const bool enable_debugging =
322 exe_ctx.GetTargetPtr() &&
323 exe_ctx.GetTargetPtr()->GetDebugUtilityExpression();
324 EvaluateExpressionOptions real_options = options;
325 real_options.SetDebug(false); // This halts the expression for debugging.
326 real_options.SetGenerateDebugInfo(enable_debugging);
327 real_options.SetUnwindOnError(!enable_debugging);
328 real_options.SetIgnoreBreakpoints(!enable_debugging);
329
330 lldb::addr_t args_addr;
331
332 if (args_addr_ptr != nullptr)
333 args_addr = *args_addr_ptr;
334 else
335 args_addr = LLDB_INVALID_ADDRESS;
336
337 if (CompileFunction(exe_ctx.GetThreadSP(), diagnostic_manager) != 0)
338 return lldb::eExpressionSetupError;
339
340 if (args_addr == LLDB_INVALID_ADDRESS) {
341 if (!InsertFunction(exe_ctx, args_addr, diagnostic_manager))
342 return lldb::eExpressionSetupError;
343 }
344
345 Log *log(GetLog(LLDBLog::Expressions | LLDBLog::Step));
346
347 LLDB_LOGF(log,
348 "== [FunctionCaller::ExecuteFunction] Executing function \"%s\" ==",
349 m_name.c_str());
350
351 lldb::ThreadPlanSP call_plan_sp = GetThreadPlanToCallFunction(
352 exe_ctx, args_addr, real_options, diagnostic_manager);
353 if (!call_plan_sp)
354 return lldb::eExpressionSetupError;
355
356 // We need to make sure we record the fact that we are running an expression
357 // here otherwise this fact will fail to be recorded when fetching an
358 // Objective-C object description
359 if (exe_ctx.GetProcessPtr())
360 exe_ctx.GetProcessPtr()->SetRunningUserExpression(true);
361
362 return_value = exe_ctx.GetProcessRef().RunThreadPlan(
363 exe_ctx, call_plan_sp, real_options, diagnostic_manager);
364
365 if (log) {
366 if (return_value != lldb::eExpressionCompleted) {
367 LLDB_LOGF(log,
368 "== [FunctionCaller::ExecuteFunction] Execution of \"%s\" "
369 "completed abnormally: %s ==",
370 m_name.c_str(),
371 Process::ExecutionResultAsCString(return_value));
372 } else {
373 LLDB_LOGF(log,
374 "== [FunctionCaller::ExecuteFunction] Execution of \"%s\" "
375 "completed normally ==",
376 m_name.c_str());
377 }
378 }
379
380 if (exe_ctx.GetProcessPtr())
381 exe_ctx.GetProcessPtr()->SetRunningUserExpression(false);
382
383 if (args_addr_ptr != nullptr)
384 *args_addr_ptr = args_addr;
385
386 if (return_value != lldb::eExpressionCompleted)
387 return return_value;
388
389 FetchFunctionResults(exe_ctx, args_addr, results);
390
391 if (args_addr_ptr == nullptr)
392 DeallocateFunctionResults(exe_ctx, args_addr);
393
394 return lldb::eExpressionCompleted;
395 }
396