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(module_sp: 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(severity: eDiagnosticSeverityError, format: "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(severity: eDiagnosticSeverityError,
78 format: "process does not match the stored process.");
79 return false;
80 }
81
82 if (process->GetState() != lldb::eStateStopped) {
83 diagnostic_manager.Printf(severity: eDiagnosticSeverityError,
84 format: "process is not stopped");
85 return false;
86 }
87
88 if (!m_compiled) {
89 diagnostic_manager.Printf(severity: eDiagnosticSeverityError,
90 format: "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 func_addr&: m_jit_start_addr, func_end&: m_jit_end_addr, execution_unit_sp&: m_execution_unit_sp, exe_ctx,
101 can_interpret, execution_policy: eExecutionPolicyAlways));
102
103 if (!jit_error.Success()) {
104 diagnostic_manager.Printf(severity: eDiagnosticSeverityError,
105 format: "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(file: jit_file, object_name: ConstString());
118 m_jit_module_wp = jit_module_sp;
119 process->GetTarget().GetImages().Append(module_sp: jit_module_sp,
120 notify: 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, arg_values&: 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(severity: eDiagnosticSeverityError,
148 str: "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 size: m_struct_size, permissions: lldb::ePermissionsReadable | lldb::ePermissionsWritable,
169 error);
170 if (args_addr_ref == LLDB_INVALID_ADDRESS)
171 return false;
172 m_wrapper_args_addrs.push_back(x: args_addr_ref);
173 } else {
174 // Make sure this is an address that we've already handed out.
175 if (find(first: m_wrapper_args_addrs.begin(), last: m_wrapper_args_addrs.end(),
176 val: 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(target: exe_ctx.GetTargetPtr()));
184 uint64_t first_offset = m_member_offsets[0];
185 process->WriteScalarToMemory(vm_addr: args_addr_ref + first_offset, scalar: fun_addr,
186 size: 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 severity: eDiagnosticSeverityError,
196 format: "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(idx: 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: &exe_ctx);
218
219 if (!process->WriteScalarToMemory(vm_addr: args_addr_ref + offset, scalar: arg_scalar,
220 size: 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(severity: eDiagnosticSeverityError, str: "no process");
235 return false;
236 }
237 if (process->GetState() != lldb::eStateStopped) {
238 diagnostic_manager.PutString(severity: eDiagnosticSeverityError, str: "process running");
239 return false;
240 }
241 if (CompileFunction(thread_to_use_sp: 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(mask: 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(mask: 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 severity: eDiagnosticSeverityError,
271 str: "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(mask: 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 load_addr: args_addr + m_return_offset, byte_size: m_return_size, fail_value: 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(first: m_wrapper_args_addrs.begin(), last: m_wrapper_args_addrs.end(),
331 val: args_addr);
332 if (pos != m_wrapper_args_addrs.end())
333 m_wrapper_args_addrs.erase(position: pos);
334
335 exe_ctx.GetProcessRef().DeallocateMemory(ptr: 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(thread_to_use_sp: 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_ref&: args_addr, diagnostic_manager))
368 return lldb::eExpressionSetupError;
369 }
370
371 Log *log(GetLog(mask: 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, options: 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, thread_plan_sp&: call_plan_sp, options: 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, ret_value&: results);
416
417 if (args_addr_ptr == nullptr)
418 DeallocateFunctionResults(exe_ctx, args_addr);
419
420 return lldb::eExpressionCompleted;
421}
422

source code of lldb/source/Expression/FunctionCaller.cpp