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/Log.h"
28 #include "lldb/Utility/State.h"
29
30 using namespace lldb_private;
31
32 char FunctionCaller::ID;
33
34 // FunctionCaller constructor
FunctionCaller(ExecutionContextScope & exe_scope,const CompilerType & return_type,const Address & functionAddress,const ValueList & arg_value_list,const char * name)35 FunctionCaller::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
~FunctionCaller()54 FunctionCaller::~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
WriteFunctionWrapper(ExecutionContext & exe_ctx,DiagnosticManager & diagnostic_manager)63 bool 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
WriteFunctionArguments(ExecutionContext & exe_ctx,lldb::addr_t & args_addr_ref,DiagnosticManager & diagnostic_manager)115 bool 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
WriteFunctionArguments(ExecutionContext & exe_ctx,lldb::addr_t & args_addr_ref,ValueList & arg_values,DiagnosticManager & diagnostic_manager)125 bool 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
InsertFunction(ExecutionContext & exe_ctx,lldb::addr_t & args_addr_ref,DiagnosticManager & diagnostic_manager)211 bool 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
GetThreadPlanToCallFunction(ExecutionContext & exe_ctx,lldb::addr_t args_addr,const EvaluateExpressionOptions & options,DiagnosticManager & diagnostic_manager)228 lldb::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
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(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
DeallocateFunctionResults(ExecutionContext & exe_ctx,lldb::addr_t args_addr)302 void 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
ExecuteFunction(ExecutionContext & exe_ctx,lldb::addr_t * args_addr_ptr,const EvaluateExpressionOptions & options,DiagnosticManager & diagnostic_manager,Value & results)313 lldb::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: %s ==",
368 m_name.c_str(),
369 Process::ExecutionResultAsCString(return_value));
370 } else {
371 LLDB_LOGF(log,
372 "== [FunctionCaller::ExecuteFunction] Execution of \"%s\" "
373 "completed normally ==",
374 m_name.c_str());
375 }
376 }
377
378 if (exe_ctx.GetProcessPtr())
379 exe_ctx.GetProcessPtr()->SetRunningUserExpression(false);
380
381 if (args_addr_ptr != nullptr)
382 *args_addr_ptr = args_addr;
383
384 if (return_value != lldb::eExpressionCompleted)
385 return return_value;
386
387 FetchFunctionResults(exe_ctx, args_addr, results);
388
389 if (args_addr_ptr == nullptr)
390 DeallocateFunctionResults(exe_ctx, args_addr);
391
392 return lldb::eExpressionCompleted;
393 }
394