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
32using namespace lldb_private;
33
34char FunctionCaller::ID;
35
36// FunctionCaller constructor
37FunctionCaller::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
57FunctionCaller::~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(module_sp: jit_module_sp);
63 }
64}
65
66bool FunctionCaller::WriteFunctionWrapper(
67 ExecutionContext &exe_ctx, DiagnosticManager &diagnostic_manager) {
68 Process *process = exe_ctx.GetProcessPtr();
69
70 if (!process) {
71 diagnostic_manager.Printf(severity: lldb::eSeverityError, format: "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(severity: lldb::eSeverityError,
79 format: "process does not match the stored process.");
80 return false;
81 }
82
83 if (process->GetState() != lldb::eStateStopped) {
84 diagnostic_manager.Printf(severity: lldb::eSeverityError, format: "process is not stopped");
85 return false;
86 }
87
88 if (!m_compiled) {
89 diagnostic_manager.Printf(severity: lldb::eSeverityError, format: "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 func_addr&: m_jit_start_addr, func_end&: m_jit_end_addr, execution_unit_sp&: m_execution_unit_sp, exe_ctx,
100 can_interpret, execution_policy: eExecutionPolicyAlways));
101
102 if (!jit_error.Success()) {
103 diagnostic_manager.Printf(severity: lldb::eSeverityError,
104 format: "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(file: jit_file, object_name: ConstString());
117 m_jit_module_wp = jit_module_sp;
118 process->GetTarget().GetImages().Append(module_sp: jit_module_sp,
119 notify: 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
130bool FunctionCaller::WriteFunctionArguments(
131 ExecutionContext &exe_ctx, lldb::addr_t &args_addr_ref,
132 DiagnosticManager &diagnostic_manager) {
133 return WriteFunctionArguments(exe_ctx, args_addr_ref, arg_values&: 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
140bool 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(severity: lldb::eSeverityError,
147 str: "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 size: m_struct_size, permissions: lldb::ePermissionsReadable | lldb::ePermissionsWritable,
168 error);
169 if (args_addr_ref == LLDB_INVALID_ADDRESS)
170 return false;
171 m_wrapper_args_addrs.push_back(x: args_addr_ref);
172 } else {
173 // Make sure this is an address that we've already handed out.
174 if (!llvm::is_contained(Range&: m_wrapper_args_addrs, Element: 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(target: exe_ctx.GetTargetPtr()));
181 uint64_t first_offset = m_member_offsets[0];
182 process->WriteScalarToMemory(vm_addr: args_addr_ref + first_offset, scalar: fun_addr,
183 size: 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 severity: lldb::eSeverityError,
193 format: "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(idx: 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: &exe_ctx);
215
216 if (!process->WriteScalarToMemory(vm_addr: args_addr_ref + offset, scalar: arg_scalar,
217 size: arg_scalar.GetByteSize(), error))
218 return false;
219 }
220
221 return true;
222}
223
224bool 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(severity: lldb::eSeverityError, str: "no process");
232 return false;
233 }
234 if (process->GetState() != lldb::eStateStopped) {
235 diagnostic_manager.PutString(severity: lldb::eSeverityError, str: "process running");
236 return false;
237 }
238 if (CompileFunction(thread_to_use_sp: 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(mask: 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
252lldb::ThreadPlanSP FunctionCaller::GetThreadPlanToCallFunction(
253 ExecutionContext &exe_ctx, lldb::addr_t args_addr,
254 const EvaluateExpressionOptions &options,
255 DiagnosticManager &diagnostic_manager) {
256 Log *log(GetLog(mask: 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 severity: lldb::eSeverityError, str: "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
284bool 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(mask: 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 load_addr: args_addr + m_return_offset, byte_size: m_return_size, fail_value: 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
323void FunctionCaller::DeallocateFunctionResults(ExecutionContext &exe_ctx,
324 lldb::addr_t args_addr) {
325 std::list<lldb::addr_t>::iterator pos;
326 pos = llvm::find(Range&: m_wrapper_args_addrs, Val: args_addr);
327 if (pos != m_wrapper_args_addrs.end())
328 m_wrapper_args_addrs.erase(position: pos);
329
330 exe_ctx.GetProcessRef().DeallocateMemory(ptr: args_addr);
331}
332
333lldb::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(thread_to_use_sp: 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_ref&: args_addr, diagnostic_manager))
367 return lldb::eExpressionSetupError;
368 }
369
370 Log *log(GetLog(mask: 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, options: 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, thread_plan_sp&: call_plan_sp, options: 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, ret_value&: results);
414
415 if (args_addr_ptr == nullptr)
416 DeallocateFunctionResults(exe_ctx, args_addr);
417
418 return lldb::eExpressionCompleted;
419}
420

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